Journal articles on the topic 'Src homology 2 domain (SH2 domain)'

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1

Tian, M., and G. S. Martin. "The role of the Src homology domains in morphological transformation by v-src." Molecular Biology of the Cell 8, no. 7 (July 1997): 1183–93. http://dx.doi.org/10.1091/mbc.8.7.1183.

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The Src homology (SH2 and SH3) domains of v-Src are required for transformation of Rat-2 cells and for wild-type (morphr) transformation of chicken embryo fibroblasts (CEFs). We report herein that the N-terminal domains of v-Src, when expressed in trans, cannot complement the transformation defect of a deletion mutant lacking the "unique," SH3, and SH2 regions. However, the same regions of Src can promote transformation when translocated to the C terminus of v-Src, although the transformation of CEFs is somewhat slower. We conclude that the SH3 and SH2 domains must be present in cis to the catalytic domain to promote transformation but that transformation is not dependent on the precise intramolecular location of these domains. In CEFSs and in Rat-2 cells, the expression of wild-type v-Src results in tyrosine phosphorylation of proteins that bind to the v-Src SH3 and SH2 domains in vitro; mutations in the SH2 or SH3 and SH2 domains prevent the phosphorylation of these proteins. These findings are most consistent with models in which the SH3 and SH2 domains of v-Src directly or indirectly target the catalytic domain to substrates involved in transformation. However, the N-terminal domains of v-Src can promote tyrosine phosphorylation of certain proteins, in particular p130Cas, even when expressed in the absence of the catalytic domain, indicating that the N-terminal domains of v-Src have effects that are independent of the catalytic domain.
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2

Koch, C. A., M. F. Moran, D. Anderson, X. Q. Liu, G. Mbamalu, and T. Pawson. "Multiple SH2-mediated interactions in v-src-transformed cells." Molecular and Cellular Biology 12, no. 3 (March 1992): 1366–74. http://dx.doi.org/10.1128/mcb.12.3.1366-1374.1992.

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The Src homology 2 (SH2) domain is a noncatalytic region which is conserved among a number of signaling and transforming proteins, including cytoplasmic protein-tyrosine kinases and Ras GTPase-activating protein (GAP). Genetic and biochemical data indicate that the SH2 domain of the p60v-src (v-Src) protein-tyrosine kinase is required for full v-src transforming activity and may direct the association of v-Src with specific tyrosine-phosphorylated proteins. To test the ability of the v-Src SH2 domain to mediate protein-protein interactions, v-Src polypeptides were expressed as fusion proteins in Escherichia coli. The bacterial v-Src SH2 domain bound a series of tyrosine-phosphorylated proteins in a lysate of v-src-transformed Rat-2 cells, including prominent species of 130 and 62 kDa (p130 and p62). The p130 and p62 tyrosine-phosphorylated proteins that complexed v-Src SH2 in vitro also associated with v-Src in v-src-transformed Rat-2 cells; this in vivo binding was dependent on the v-Src SH2 domain. In addition to binding soluble p62 and p130, the SH2 domains of v-Src, GAP, and v-Crk directly recognized these phosphotyrosine-containing proteins which had been previously denatured and immobilized on a filter. In addition, the SH2 domains of GAP and v-Crk bound to the GAP-associated protein p190 immobilized on a nitrocellulose membrane. These results show that SH2 domains bind directly to tyrosine-phosphorylated proteins and that the Src SH2 domain can bind phosphorylated targets of the v-Src kinase domain.(ABSTRACT TRUNCATED AT 250 WORDS)
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3

Koch, C. A., M. F. Moran, D. Anderson, X. Q. Liu, G. Mbamalu, and T. Pawson. "Multiple SH2-mediated interactions in v-src-transformed cells." Molecular and Cellular Biology 12, no. 3 (March 1992): 1366–74. http://dx.doi.org/10.1128/mcb.12.3.1366.

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The Src homology 2 (SH2) domain is a noncatalytic region which is conserved among a number of signaling and transforming proteins, including cytoplasmic protein-tyrosine kinases and Ras GTPase-activating protein (GAP). Genetic and biochemical data indicate that the SH2 domain of the p60v-src (v-Src) protein-tyrosine kinase is required for full v-src transforming activity and may direct the association of v-Src with specific tyrosine-phosphorylated proteins. To test the ability of the v-Src SH2 domain to mediate protein-protein interactions, v-Src polypeptides were expressed as fusion proteins in Escherichia coli. The bacterial v-Src SH2 domain bound a series of tyrosine-phosphorylated proteins in a lysate of v-src-transformed Rat-2 cells, including prominent species of 130 and 62 kDa (p130 and p62). The p130 and p62 tyrosine-phosphorylated proteins that complexed v-Src SH2 in vitro also associated with v-Src in v-src-transformed Rat-2 cells; this in vivo binding was dependent on the v-Src SH2 domain. In addition to binding soluble p62 and p130, the SH2 domains of v-Src, GAP, and v-Crk directly recognized these phosphotyrosine-containing proteins which had been previously denatured and immobilized on a filter. In addition, the SH2 domains of GAP and v-Crk bound to the GAP-associated protein p190 immobilized on a nitrocellulose membrane. These results show that SH2 domains bind directly to tyrosine-phosphorylated proteins and that the Src SH2 domain can bind phosphorylated targets of the v-Src kinase domain.(ABSTRACT TRUNCATED AT 250 WORDS)
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4

Song, X., X. Shang, T. Ju, R. Cerny, W. Niu, and J. Guo. "A photoactivatable Src homology 2 (SH2) domain." RSC Advances 6, no. 56 (2016): 51120–24. http://dx.doi.org/10.1039/c6ra06211c.

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5

Klippel, A., J. A. Escobedo, W. J. Fantl, and L. T. Williams. "The C-terminal SH2 domain of p85 accounts for the high affinity and specificity of the binding of phosphatidylinositol 3-kinase to phosphorylated platelet-derived growth factor beta receptor." Molecular and Cellular Biology 12, no. 4 (April 1992): 1451–59. http://dx.doi.org/10.1128/mcb.12.4.1451-1459.1992.

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Upon stimulation by its ligand, the platelet-derived growth factor (PDGF) receptor associates with the 85-kDa subunit of phosphatidylinositol (PI) 3-kinase. The 85-kDa protein (p85) contains two Src homology 2 (SH2) domains and one SH3 domain. To define the part of p85 that interacts with the PDGF receptor, a series of truncated p85 mutants was analyzed for association with immobilized PDGF receptor in vitro. We found that a fragment of p85 that contains a single Src homology domain, the C-terminal SH2 domain (SH2-C), was sufficient for directing the high-affinity interaction with the receptor. Half-maximal binding of SH2-C to the receptor was observed at an SH2-C concentration of 0.06 nM. SH2-C, like full-length p85, was able to distinguish between wild-type PDGF receptor and a mutant receptor lacking the PI 3-kinase binding site. An excess of SH2-C blocked binding of full-length p85 and PI 3-kinase to the receptor but did not interfere with the binding of two other SH2-containing proteins, phospholipase C-gamma and GTPase-activating protein. These results demonstrate that a region of p85 containing a single SH2 domain accounts both for the high affinity and specificity of binding of PI 3-kinase to the PDGF receptor.
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6

Klippel, A., J. A. Escobedo, W. J. Fantl, and L. T. Williams. "The C-terminal SH2 domain of p85 accounts for the high affinity and specificity of the binding of phosphatidylinositol 3-kinase to phosphorylated platelet-derived growth factor beta receptor." Molecular and Cellular Biology 12, no. 4 (April 1992): 1451–59. http://dx.doi.org/10.1128/mcb.12.4.1451.

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Upon stimulation by its ligand, the platelet-derived growth factor (PDGF) receptor associates with the 85-kDa subunit of phosphatidylinositol (PI) 3-kinase. The 85-kDa protein (p85) contains two Src homology 2 (SH2) domains and one SH3 domain. To define the part of p85 that interacts with the PDGF receptor, a series of truncated p85 mutants was analyzed for association with immobilized PDGF receptor in vitro. We found that a fragment of p85 that contains a single Src homology domain, the C-terminal SH2 domain (SH2-C), was sufficient for directing the high-affinity interaction with the receptor. Half-maximal binding of SH2-C to the receptor was observed at an SH2-C concentration of 0.06 nM. SH2-C, like full-length p85, was able to distinguish between wild-type PDGF receptor and a mutant receptor lacking the PI 3-kinase binding site. An excess of SH2-C blocked binding of full-length p85 and PI 3-kinase to the receptor but did not interfere with the binding of two other SH2-containing proteins, phospholipase C-gamma and GTPase-activating protein. These results demonstrate that a region of p85 containing a single SH2 domain accounts both for the high affinity and specificity of binding of PI 3-kinase to the PDGF receptor.
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7

Xing, Z., H. C. Chen, J. K. Nowlen, S. J. Taylor, D. Shalloway, and J. L. Guan. "Direct interaction of v-Src with the focal adhesion kinase mediated by the Src SH2 domain." Molecular Biology of the Cell 5, no. 4 (April 1994): 413–21. http://dx.doi.org/10.1091/mbc.5.4.413.

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The recently described focal adhesion kinase (FAK) has been implicated in signal transduction pathways initiated by cell adhesion receptor integrins and by neuropeptide growth factors. To examine the mechanisms by which FAK relays signals from the membrane to the cell interior, we carried out a series of experiments to detect potential FAK interactions with proteins containing Src homology 2 (SH2) domains that are important intracellular signaling molecules. Using v-Src-transformed NIH3T3 cells, we showed that FAK was present in the immune-complex precipitated by anti-Src antibody, suggesting potential interaction of FAK with v-Src in vivo. We also showed potentially direct interaction of FAK with v-Src in vivo using the yeast two-hybrid system. Using recombinant FAK expressed in insect cells and bacterial fusion proteins containing Src SH2 domains, we showed direct binding of FAK to the Src SH2 domain but not to the SH3 domain in vitro. A kinase-defective mutant of FAK, which is not autophosphorylated, did not interact with the Src SH2 domain under the same conditions, suggesting the involvement of the FAK autophosphorylation sites. Treatment of FAK with a protein-tyrosine phosphatase decreased its binding to the Src SH2 domain, whereas autophosphorylation in vitro increased its binding. These results confirm the importance of FAK autophosphorylation sites in its interaction with SH2 domain-containing proteins. Taken together, these results suggest that FAK may mediate signal transduction events initiated on the cell surface by kinase activation and autophosphorylation that result in its binding to other key intracellular signaling molecules.
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8

Bibbins, K. B., H. Boeuf, and H. E. Varmus. "Binding of the Src SH2 domain to phosphopeptides is determined by residues in both the SH2 domain and the phosphopeptides." Molecular and Cellular Biology 13, no. 12 (December 1993): 7278–87. http://dx.doi.org/10.1128/mcb.13.12.7278-7287.1993.

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Src homology 2 (SH2) domains are found in a variety of signaling proteins and bind phosphotyrosine-containing peptide sequences. To explore the binding properties of the SH2 domain of the Src protein kinase, we used immobilized phosphopeptides to bind purified glutathione S-transferase-Src SH2 fusion proteins. With this assay, as well as a free-peptide competition assay, we have estimated the affinities of the Src SH2 domain for various phosphopeptides relative to a Src SH2-phosphopeptide interaction whose Kd has been determined previously (YEEI-P; Kd = 4 nM). Two Src-derived phosphopeptides, one containing the regulatory C-terminal Tyr-527 and another containing the autophosphorylation site Tyr-416, bind the Src SH2 domain in a specific though low-affinity manner (with about 10(4)-lower affinity than the YEEI-P peptide). A platelet-derived growth factor receptor (PDGF-R) phosphopeptide containing Tyr-857 does not bind appreciably to the Src SH2 domain, suggesting it is not the PDGF-R binding site for Src as previously reported. However, another PDGF-R-derived phosphopeptide containing Tyr-751 does bind the Src SH2 domain (with an affinity approximately 2 orders of magnitude lower than that of YEEI-P). All of the phosphopeptides which bind to the Src SH2 domain contain a glutamic acid at position -3 or -4 with respect to phosphotyrosine; changing this residue to alanine greatly diminishes binding. We have also tested Src SH2 mutants for their binding properties and have interpreted our results in light of the recent crystal structure solution for the Src SH2 domain. Mutations in various conserved and nonconserved residues (R155A, R155K, N198E, H201R, and H201L) cause slight reductions in binding, while two mutations cause severe reductions. The W148E mutant domain, which alters the invariant tryptophan that marks the N-terminal border of the SH2 domain, binds poorly to phosphopeptides. Inclusion of the SH3 domain in the fusion protein partially restores the binding by the W148E mutant. A change in the invariant arginine that coordinates twice with phosphotyrosine in the peptide (R175L) results in a nearly complete loss of binding. The R175L mutant does display high affinity for the PDGF-R peptide containing Tyr-751, via an interaction that is at least partly phosphotyrosine independent. We have used this interaction to show that the R175L mutation also disrupts the intramolecular interaction between the Src SH2 domain and the phosphorylated C terminus within the context of the entire Src protein; thus, the binding properties observed for mutant domains in an in vitro assay appear to mimic those that occur in vivo.
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9

Bibbins, K. B., H. Boeuf, and H. E. Varmus. "Binding of the Src SH2 domain to phosphopeptides is determined by residues in both the SH2 domain and the phosphopeptides." Molecular and Cellular Biology 13, no. 12 (December 1993): 7278–87. http://dx.doi.org/10.1128/mcb.13.12.7278.

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Src homology 2 (SH2) domains are found in a variety of signaling proteins and bind phosphotyrosine-containing peptide sequences. To explore the binding properties of the SH2 domain of the Src protein kinase, we used immobilized phosphopeptides to bind purified glutathione S-transferase-Src SH2 fusion proteins. With this assay, as well as a free-peptide competition assay, we have estimated the affinities of the Src SH2 domain for various phosphopeptides relative to a Src SH2-phosphopeptide interaction whose Kd has been determined previously (YEEI-P; Kd = 4 nM). Two Src-derived phosphopeptides, one containing the regulatory C-terminal Tyr-527 and another containing the autophosphorylation site Tyr-416, bind the Src SH2 domain in a specific though low-affinity manner (with about 10(4)-lower affinity than the YEEI-P peptide). A platelet-derived growth factor receptor (PDGF-R) phosphopeptide containing Tyr-857 does not bind appreciably to the Src SH2 domain, suggesting it is not the PDGF-R binding site for Src as previously reported. However, another PDGF-R-derived phosphopeptide containing Tyr-751 does bind the Src SH2 domain (with an affinity approximately 2 orders of magnitude lower than that of YEEI-P). All of the phosphopeptides which bind to the Src SH2 domain contain a glutamic acid at position -3 or -4 with respect to phosphotyrosine; changing this residue to alanine greatly diminishes binding. We have also tested Src SH2 mutants for their binding properties and have interpreted our results in light of the recent crystal structure solution for the Src SH2 domain. Mutations in various conserved and nonconserved residues (R155A, R155K, N198E, H201R, and H201L) cause slight reductions in binding, while two mutations cause severe reductions. The W148E mutant domain, which alters the invariant tryptophan that marks the N-terminal border of the SH2 domain, binds poorly to phosphopeptides. Inclusion of the SH3 domain in the fusion protein partially restores the binding by the W148E mutant. A change in the invariant arginine that coordinates twice with phosphotyrosine in the peptide (R175L) results in a nearly complete loss of binding. The R175L mutant does display high affinity for the PDGF-R peptide containing Tyr-751, via an interaction that is at least partly phosphotyrosine independent. We have used this interaction to show that the R175L mutation also disrupts the intramolecular interaction between the Src SH2 domain and the phosphorylated C terminus within the context of the entire Src protein; thus, the binding properties observed for mutant domains in an in vitro assay appear to mimic those that occur in vivo.
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10

Songyang, Z., S. E. Shoelson, J. McGlade, P. Olivier, T. Pawson, X. R. Bustelo, M. Barbacid, H. Sabe, H. Hanafusa, and T. Yi. "Specific motifs recognized by the SH2 domains of Csk, 3BP2, fps/fes, GRB-2, HCP, SHC, Syk, and Vav." Molecular and Cellular Biology 14, no. 4 (April 1994): 2777–85. http://dx.doi.org/10.1128/mcb.14.4.2777-2785.1994.

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Src homology 2 (SH2) domains provide specificity to intracellular signaling by binding to specific phosphotyrosine (phospho-Tyr)-containing sequences. We recently developed a technique using a degenerate phosphopeptide library to predict the specificity of individual SH2 domains (src family members, Abl, Nck, Sem5, phospholipase C-gamma, p85 subunit of phosphatidylinositol-3-kinase, and SHPTP2 (Z. Songyang, S. E. Shoelson, M. Chaudhuri, G. Gish, T. Pawson, W. G. Haser, F. King, T. Roberts, S. Ratnofsky, R. J. Lechleider, B. G. Neel, R. B. Birge, J. E. Fajardo, M. M. Chou, H. Hanafusa, B. Schaffhausen, and L. C. Cantley, Cell 72:767-778, 1993). We report here the optimal recognition motifs for SH2 domains from GRB-2, Drk, Csk, Vav, fps/fes, SHC, Syk (carboxy-terminal SH2), 3BP2, and HCP (amino-terminal SH2 domain, also called PTP1C and SHPTP1). As predicted, SH2 domains from proteins that fall into group I on the basis of a Phe or Tyr at the beta D5 position (GRB-2, 3BP2, Csk, fps/fes, Syk C-terminal SH2) select phosphopeptides with the general motif phospho-Tyr-hydrophilic (residue)-hydrophilic (residue)-hydrophobic (residue). The SH2 domains of SHC and HCP (group III proteins with Ile, Leu, of Cys at the beta D5 position) selected the general motif phospho-Tyr-hydrophobic-Xxx-hydrophobic, also as predicted. Vav, which has a Thr at the beta D5 position, selected phospho-Tyr-Met-Glu-Pro as the optimal motif. Each SH2 domain selected a unique optimal motif distinct from motifs previously determined for other SH2 domains. These motifs are used to predict potential sites in signaling proteins for interaction with specific SH2 domain-containing proteins. The Syk SH2 domain is predicted to bind to Tyr-hydrophilic-hydrophilic-Leu/Ile motifs like those repeated at 10-residue intervals in T- and B-cell receptor-associated proteins. SHC is predicted to bind to a subgroup og these same motifs. A structural basis for the association of Csk with Src family members is also suggested from these studies.
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11

Songyang, Z., S. E. Shoelson, J. McGlade, P. Olivier, T. Pawson, X. R. Bustelo, M. Barbacid, H. Sabe, H. Hanafusa, and T. Yi. "Specific motifs recognized by the SH2 domains of Csk, 3BP2, fps/fes, GRB-2, HCP, SHC, Syk, and Vav." Molecular and Cellular Biology 14, no. 4 (April 1994): 2777–85. http://dx.doi.org/10.1128/mcb.14.4.2777.

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Src homology 2 (SH2) domains provide specificity to intracellular signaling by binding to specific phosphotyrosine (phospho-Tyr)-containing sequences. We recently developed a technique using a degenerate phosphopeptide library to predict the specificity of individual SH2 domains (src family members, Abl, Nck, Sem5, phospholipase C-gamma, p85 subunit of phosphatidylinositol-3-kinase, and SHPTP2 (Z. Songyang, S. E. Shoelson, M. Chaudhuri, G. Gish, T. Pawson, W. G. Haser, F. King, T. Roberts, S. Ratnofsky, R. J. Lechleider, B. G. Neel, R. B. Birge, J. E. Fajardo, M. M. Chou, H. Hanafusa, B. Schaffhausen, and L. C. Cantley, Cell 72:767-778, 1993). We report here the optimal recognition motifs for SH2 domains from GRB-2, Drk, Csk, Vav, fps/fes, SHC, Syk (carboxy-terminal SH2), 3BP2, and HCP (amino-terminal SH2 domain, also called PTP1C and SHPTP1). As predicted, SH2 domains from proteins that fall into group I on the basis of a Phe or Tyr at the beta D5 position (GRB-2, 3BP2, Csk, fps/fes, Syk C-terminal SH2) select phosphopeptides with the general motif phospho-Tyr-hydrophilic (residue)-hydrophilic (residue)-hydrophobic (residue). The SH2 domains of SHC and HCP (group III proteins with Ile, Leu, of Cys at the beta D5 position) selected the general motif phospho-Tyr-hydrophobic-Xxx-hydrophobic, also as predicted. Vav, which has a Thr at the beta D5 position, selected phospho-Tyr-Met-Glu-Pro as the optimal motif. Each SH2 domain selected a unique optimal motif distinct from motifs previously determined for other SH2 domains. These motifs are used to predict potential sites in signaling proteins for interaction with specific SH2 domain-containing proteins. The Syk SH2 domain is predicted to bind to Tyr-hydrophilic-hydrophilic-Leu/Ile motifs like those repeated at 10-residue intervals in T- and B-cell receptor-associated proteins. SHC is predicted to bind to a subgroup og these same motifs. A structural basis for the association of Csk with Src family members is also suggested from these studies.
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12

Joseph, Raji E., Nathaniel D. Ginder, Julie A. Hoy, Jay C. Nix, D. Bruce Fulton, Richard B. Honzatko, and Amy H. Andreotti. "Structure of the interleukin-2 tyrosine kinase Src homology 2 domain; comparison between X-ray and NMR-derived structures." Acta Crystallographica Section F Structural Biology and Crystallization Communications 68, no. 2 (January 25, 2012): 145–53. http://dx.doi.org/10.1107/s1744309111049761.

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The crystal structure of the interleukin-2 tyrosine kinase Src homology domain (Itk SH2) is described and it is found that unlike in studies of this domain using NMR spectroscopy,cis–trans-prolyl isomerization is not readily detected in the crystal structure. Based on similarities between the Itk SH2 crystal form and thecisform of the Itk SH2 NMR structure, it is concluded that it is likely that the prolyl imide bond at least in part adopts thecisconformation in the crystal form. However, the lack of high-resolution data and the dynamic nature of the proline-containing loop mean that the precise imide-bond conformation cannot be determined and prolylcis–transisomerization in the crystal cannot be ruled out. Given the preponderance of structures that have been solved by X-ray crystallography in the Protein Data Bank, this result supports the notion that prolyl isomerization in folded proteins has been underestimated among known structures. Interestingly, while the precise status of the proline residue is ambiguous, Itk SH2 crystallizes as a domain-swapped dimer. The domain-swapped structure of Itk SH2 is similar to the domain-swapped SH2 domains of Grb2 and Nck, with domain swapping occurring at the β-meander region of all three SH2 domains. Thus, for Itk SH2 structural analysis by NMR spectroscopy and X-ray crystallography revealed very different structural features: proline isomerizationversusdomain-swapped dimerization, respectively.
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13

She, H. Y., S. Rockow, J. Tang, R. Nishimura, E. Y. Skolnik, M. Chen, B. Margolis, and W. Li. "Wiskott-Aldrich syndrome protein is associated with the adapter protein Grb2 and the epidermal growth factor receptor in living cells." Molecular Biology of the Cell 8, no. 9 (September 1997): 1709–21. http://dx.doi.org/10.1091/mbc.8.9.1709.

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Src homology domains [i.e., Src homology domain 2 (SH2) and Src homology domain 3 (SH3)] play a critical role in linking receptor tyrosine kinases to downstream signaling networks. A well-defined function of the SH3-SH2-SH3 adapter Grb2 is to link receptor tyrosine kinases, such as the epidermal growth factor receptor (EGFR), to the p21ras-signaling pathway. Grb2 has also been implicated to play a role in growth factor-regulated actin assembly and receptor endocytosis, although the underlying mechanisms remain unclear. In this study, we show that Grb2 interacts through its SH3 domains with the human Wiskott-Aldrich syndrome protein (WASp), which plays a role in regulation of the actin cytoskeleton. We find that WASp is expressed in a variety of cell types and is exclusively cytoplasmic. Although the N-terminal SH3 domain of Grb2 binds significantly stronger than the C-terminal SH3 domain to WASp, full-length Grb2 shows the strongest binding. Both phosphorylation of WASp and its interaction with Grb2, as well as with another adapter protein Nck, remain constitutive in serum-starved or epidermal growth factor-stimulated cells. WASp coimmunoprecipitates with the activated EGFR after epidermal growth factor stimulation. Purified glutathione S-transferase-full-length-Grb2 fusion protein, but not the individual domains of Grb2, enhances the association of WASp with the EGFR, suggesting that Grb2 mediates the association of WASp with EGFR. This study suggests that Grb2 translocates WASp from the cytoplasm to the plasma membrane and the Grb2-WASp complex may play a role in linking receptor tyrosine kinases to the actin cytoskeleton.
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14

Koch, C. A., M. Moran, I. Sadowski, and T. Pawson. "The common src homology region 2 domain of cytoplasmic signaling proteins is a positive effector of v-fps tyrosine kinase function." Molecular and Cellular Biology 9, no. 10 (October 1989): 4131–40. http://dx.doi.org/10.1128/mcb.9.10.4131-4140.1989.

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A conserved noncatalytic domain SH2 (for src homology region 2) is located immediately N terminal to the kinase domains of all cytoplasmic protein-tyrosine kinases. We found that the wild-type v-fps SH2 domain stimulated the enzymatic activity of the adjacent kinase domain 10-fold and functioned as a powerful positive effector of catalytic and transforming activities within the v-fps oncoprotein (P130gag-fps). Partial proteolysis of P130gag-fps and supporting genetic data indicated that the v-fps SH2 domain exerts its effect on catalytic activity through an intramolecular interaction with the kinase domain. Amino acid alterations in the SH2 domain that impaired kinase function interfered with association of the SH2 domain with the kinase domain. Deletion of a conserved octapeptide motif converted the v-fps SH2 domain from an activator to an inhibitor of tyrosine kinase activity. This latent inhibitory activity of v-fps SH2 has functional implications for phospholipase C-gamma and p21ras GTPase-activating protein, both of which have two distinct SH2 domains suggestive of complex regulation. In addition to regulating the specific activity of the kinase domain, the SH2 domain of P130gag-fps was also found to be required for the tyrosine phosphorylation of specific cellular proteins, notably polypeptides of 124 and 62 kilodaltons. The SH2 domain therefore appears to play a dual role in regulation of kinase activity and recognition of cellular substrates.
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15

Koch, C. A., M. Moran, I. Sadowski, and T. Pawson. "The common src homology region 2 domain of cytoplasmic signaling proteins is a positive effector of v-fps tyrosine kinase function." Molecular and Cellular Biology 9, no. 10 (October 1989): 4131–40. http://dx.doi.org/10.1128/mcb.9.10.4131.

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A conserved noncatalytic domain SH2 (for src homology region 2) is located immediately N terminal to the kinase domains of all cytoplasmic protein-tyrosine kinases. We found that the wild-type v-fps SH2 domain stimulated the enzymatic activity of the adjacent kinase domain 10-fold and functioned as a powerful positive effector of catalytic and transforming activities within the v-fps oncoprotein (P130gag-fps). Partial proteolysis of P130gag-fps and supporting genetic data indicated that the v-fps SH2 domain exerts its effect on catalytic activity through an intramolecular interaction with the kinase domain. Amino acid alterations in the SH2 domain that impaired kinase function interfered with association of the SH2 domain with the kinase domain. Deletion of a conserved octapeptide motif converted the v-fps SH2 domain from an activator to an inhibitor of tyrosine kinase activity. This latent inhibitory activity of v-fps SH2 has functional implications for phospholipase C-gamma and p21ras GTPase-activating protein, both of which have two distinct SH2 domains suggestive of complex regulation. In addition to regulating the specific activity of the kinase domain, the SH2 domain of P130gag-fps was also found to be required for the tyrosine phosphorylation of specific cellular proteins, notably polypeptides of 124 and 62 kilodaltons. The SH2 domain therefore appears to play a dual role in regulation of kinase activity and recognition of cellular substrates.
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16

Stoica, Bogdan, Karen E. DeBell, Laurie Graham, Barbara L. Rellahan, Maria A. Alava, Jorge Laborda, and Ezio Bonvini. "The Amino-Terminal Src Homology 2 Domain of Phospholipase Cγ1 Is Essential for TCR-Induced Tyrosine Phosphorylation of Phospholipase Cγ1." Journal of Immunology 160, no. 3 (February 1, 1998): 1059–66. http://dx.doi.org/10.4049/jimmunol.160.3.1059.

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Abstract TCR engagement activates phospholipase Cγ1 (PLCγ1) via a tyrosine phosphorylation-dependent mechanism. PLCγ1 contains a pair of Src homology 2 (SH2) domains whose function is that of promoting protein interactions by binding phosphorylated tyrosine and adjacent amino acids. The role of the PLCγ1 SH2 domains in PLCγ1 phosphorylation was explored by mutational analysis of an epitope-tagged protein transiently expressed in Jurkat T cells. Mutation of the amino-terminal SH2 domain (SH2(N) domain) resulted in defective tyrosine phosphorylation of PLCγ1 in response to TCR/CD3 perturbation. In addition, the PLCγ1 SH2(N) domain mutant failed to associate with Grb2 and a 36- to 38-kDa phosphoprotein (p36–38), which has previously been recognized to interact with PLCγ1, Grb2, and other molecules involved in TCR signal transduction. Conversely, mutation of the carboxyl-terminal SH2 domain (SH2(C) domain) did not affect TCR-induced tyrosine phosphorylation of PLCγ1. Furthermore, binding of p36–38 to PLCγ1 was not abrogated by mutations of the SH2(C) domain. In contrast to TCR/CD3 ligation, treatment of cells with pervanadate induced tyrosine phosphorylation of either PLCγ1 SH2(N) or SH2(C) domain mutants to a level comparable with that of the wild-type protein, indicating that pervanadate treatment induces an alternate mechanism of PLCγ1 phosphorylation. These data indicate that the SH2(N) domain is required for TCR-induced PLCγ1 phosphorylation, presumably by participating in the formation of a complex that promotes the association of PLCγ1 with a tyrosine kinase.
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17

Duplay, P., M. Thome, F. Hervé, and O. Acuto. "p56lck interacts via its src homology 2 domain with the ZAP-70 kinase." Journal of Experimental Medicine 179, no. 4 (April 1, 1994): 1163–72. http://dx.doi.org/10.1084/jem.179.4.1163.

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p56lck, a member of the src family of protein tyrosine kinases, is an essential component in T cell receptor (TCR) signal transduction. p56lck contains a src homology 2 (SH2) domain found in a number of proteins involved in intracellular signaling. SH2 domains have been implicated in protein-protein interactions by binding to sequences in target proteins containing phosphorylated tyrosine. Using an in vitro assay, we have studied specific binding of tyrosine-phosphorylated proteins to a recombinant p56lck SH2 domain. In nonactivated Jurkat cells, two tyrosine-phosphorylated proteins were detected. Stimulation with anti-CD3 monoclonal antibodies induced the binding of seven additional tyrosine-phosphorylated proteins to the SH2 domain of p56lck. We have identified the zeta-associated tyrosine kinase, ZAP-70, as one of these proteins. Evidence suggests that binding of ZAP-70 to p56lck SH2 is direct and not mediated by zeta. The significance of this interaction was further investigated in vivo. p56lck could be coprecipitated with the zeta/ZAP-70 complex and conversely, ZAP-70 was detected in p56lck immunoprecipitates of activated Jurkat cells. The physical association of p56lck and ZAP-70 during activation supports the recently proposed functional cooperation of these two tyrosine kinases in TCR signaling.
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18

Seidel-Dugan, C., B. E. Meyer, S. M. Thomas, and J. S. Brugge. "Effects of SH2 and SH3 deletions on the functional activities of wild-type and transforming variants of c-Src." Molecular and Cellular Biology 12, no. 4 (April 1992): 1835–45. http://dx.doi.org/10.1128/mcb.12.4.1835-1845.1992.

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The amino-termina, noncatalytic half of Src contains two domains, designated the Src homology 2 (SH2) and Src homology 3 (SH3) domains, that are highly conserved among members of the Src family of tyrosine kinases. The SH2 domain (which can be further divided into the B and C homology boxes) and the SH3 domain (also referred to as the A box) are also found in several proteins otherwise unrelated to protein tyrosine kinases. It is believed that these domains are important for directing specific protein-protein interactions necessary for the proper functioning of Src. To determine the importance of the SH2 and SH3 domains in regulating the functions of c-Src, we evaluated mutants of c-Src lacking the A box (residues 88 to 137), the B box (residues 148 to 187) or the C box (residues 220 to 231). Each of these deletions caused a 14- to 30-fold increase in the in vitro level of kinase activity of c-Src. Chicken embryo fibroblasts expressing the deletion mutants displayed a transformed cell morphology, formed colonies in soft agar, and contained elevated levels of cellular phosphotyrosine-containing proteins. Src substrates p36, p85, p120, p125, the GTPase-activating protein (GAP), and several GAP-associated proteins were phosphorylated on tyrosine in cells expressing the A, B, or C box deletion mutant. p110 was highly phosphorylated in cells expressing the C box mutant, was weakly phosphorylated in cells expressing the B box mutant, and was not phosphorylated in cells expressing the A box mutant. Expression of the mutant proteins caused a reorganization of the actin cytoskeleton similar to that seen in v-Src-transformed cells. In addition, deletion of the A, B, or C box did not diminish the transforming or enzymatic activity of an activated variant of c-Src, E378G. These data indicate that deletion of the A, B, or C homology box causes an activation of the catalytic and transforming potential of c-Src and that while these mutations caused subtle differences in substrate phosphorylation, the homology boxes are not required for many of the phenotypic changes associated with transformation by Src.
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19

Seidel-Dugan, C., B. E. Meyer, S. M. Thomas, and J. S. Brugge. "Effects of SH2 and SH3 deletions on the functional activities of wild-type and transforming variants of c-Src." Molecular and Cellular Biology 12, no. 4 (April 1992): 1835–45. http://dx.doi.org/10.1128/mcb.12.4.1835.

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The amino-termina, noncatalytic half of Src contains two domains, designated the Src homology 2 (SH2) and Src homology 3 (SH3) domains, that are highly conserved among members of the Src family of tyrosine kinases. The SH2 domain (which can be further divided into the B and C homology boxes) and the SH3 domain (also referred to as the A box) are also found in several proteins otherwise unrelated to protein tyrosine kinases. It is believed that these domains are important for directing specific protein-protein interactions necessary for the proper functioning of Src. To determine the importance of the SH2 and SH3 domains in regulating the functions of c-Src, we evaluated mutants of c-Src lacking the A box (residues 88 to 137), the B box (residues 148 to 187) or the C box (residues 220 to 231). Each of these deletions caused a 14- to 30-fold increase in the in vitro level of kinase activity of c-Src. Chicken embryo fibroblasts expressing the deletion mutants displayed a transformed cell morphology, formed colonies in soft agar, and contained elevated levels of cellular phosphotyrosine-containing proteins. Src substrates p36, p85, p120, p125, the GTPase-activating protein (GAP), and several GAP-associated proteins were phosphorylated on tyrosine in cells expressing the A, B, or C box deletion mutant. p110 was highly phosphorylated in cells expressing the C box mutant, was weakly phosphorylated in cells expressing the B box mutant, and was not phosphorylated in cells expressing the A box mutant. Expression of the mutant proteins caused a reorganization of the actin cytoskeleton similar to that seen in v-Src-transformed cells. In addition, deletion of the A, B, or C box did not diminish the transforming or enzymatic activity of an activated variant of c-Src, E378G. These data indicate that deletion of the A, B, or C homology box causes an activation of the catalytic and transforming potential of c-Src and that while these mutations caused subtle differences in substrate phosphorylation, the homology boxes are not required for many of the phenotypic changes associated with transformation by Src.
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20

Northrop, J. P., M. J. Pustelnik, A. T. Lu, and J. R. Grove. "Characterization of the roles of SH2 domain-containing proteins in T-lymphocyte activation by using dominant negative SH2 domains." Molecular and Cellular Biology 16, no. 5 (May 1996): 2255–63. http://dx.doi.org/10.1128/mcb.16.5.2255.

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Activation of the T-cell antigen receptor initiates a complex signaling cascade leading to changes in cytokine gene transcription. Several proteins containing Src homology 2 (SH2) domains, capable of interacting with phosphotyrosine-containing sequences within other proteins, are involved in the activation of signaling intermediates such as p2l(ras) and phospholipase Cgamma1. In this study, we used dominant negative SH2 domains to determine the importance of SH2 domain-containing proteins for T-cell activation. We show that tandem SH2 domains of either Zap70 or Syk tyrosine kinase are potent inhibitors of signaling initiated by the T-cell receptor zeta chain in vivo while individual SH2 domains are ineffective. Thus, while only the C-terminal SH2 domains appear to have significant affinity for immunoreceptor tyrosine-based activation motifs in vitro, the N-terminal SH2 domains are necessary in vivo. We find the spacing between the tandem SH2 domains of Zap70 to be critical for in vivo interactions. The SH2 domain of the adapter protein Grb2 is an effective inhibitor in our dominant negative assay, although it has little affinity for immunoreceptor tyrosine-based activation motifs. A single point mutation that abolishes phosphotyrosine binding renders the Grb2 SH2 domain incapable of this inhibition. In contrast, the SH2 domain of Shc does not inhibit this signaling cascade. We conclude that Grb2, but not Shc, is involved in T-cell receptor signaling.
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21

Schüller, Annika C., Zamal Ahmed, James A. Levitt, Kin M. Suen, Klaus Suhling, and John E. Ladbury. "Indirect recruitment of the signalling adaptor Shc to the fibroblast growth factor receptor 2 (FGFR2)." Biochemical Journal 416, no. 2 (November 12, 2008): 189–99. http://dx.doi.org/10.1042/bj20080887.

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The adaptor protein Shc (Src homology and collagen-containing protein) plays an important role in the activation of signalling pathways downstream of RTKs (receptor tyrosine kinases) regulating diverse cellular functions, such as differentiation, adhesion, migration and mitogenesis. Despite being phosphorylated downstream of members of the FGFR (fibroblast growth factor receptor) family, a direct interaction of Shc with this receptor family has not been described to date. Various studies have suggested potential binding sites for the Shc PTB domain (phosphotyrosine-binding domain) and/or the SH2 (Src homology 2) domain on FGFR1, but no interaction of full-length Shc with these sites has been reported in vivo. In the present study, we investigated the importance of the SH2 domain and the PTB domain in recruitment of Shc to FGFR2(IIIc) to characterize the interaction of these two proteins. Confocal microscopy revealed extensive co-localization of Shc with FGFR2. The PTB domain was identified as the critical component of Shc which mediates membrane localization. Results from FLIM (fluorescence lifetime imaging microscopy) revealed that the interaction between Shc and FGFR2 is indirect, suggesting that the adaptor protein forms part of a signalling complex containing the receptor. We identified the non-RTK Src as a protein which potentially mediates the formation of such a ternary complex. Although an interaction between Src and Shc has been described previously, in the present study we implicate the Shc SH2 domain as a novel mediator of this association. The recruitment of Shc to FGFR2 via an indirect mechanism provides new insight into the regulation of protein assembly and activation of various signalling pathways downstream of this RTK.
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22

Horstmann, Martin A., and Peter Nollau. "Src Homology 2 Domain Binding as a Phosphoproteomic Approach to Signaling in Acute Lymphoblastic Leukemia." Blood 104, no. 11 (November 16, 2004): 4442. http://dx.doi.org/10.1182/blood.v104.11.4442.4442.

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Abstract A general theme of orchestrated signal transduction is played by activated receptor phosphotyrosine kinases (PTK) and receptor PTK targets which propagate signals via recognition of sequence-specific phoshorylated tyrosines by so-called Src homology 2 (SH2) domains. SH2 domain interactions are used as a means of recruiting target proteins to activated PTKs and to translocate them to the plasma membrane where many effector proteins activated by receptor PTKs such as phospholipase C-γ or PI-3 kinase have their substrates. SH2 domains make up the most prevalent type of phosphotyrosine binding domains involved in signaling downstream of activated PTKs. SH2 domains are not only present in proteins with intrinsic enzymatic activity but also in adaptor proteins which shuttle effector enzymes to target signaling complexes. Increasing numbers of diseases are known to involve phosphotyrosine specific kinases and/or phosphatases going awry exemplified by the notorious ErbB2 receptor PTK in breast cancer or the Bcr-Abl PTK in CML. Currently, the tyrosine phosphorylation state in most acute lymphoblastic leukemias is undefined which is predicted to differ among the various subgroups and to be distinct from the signaling state of normal hematopoietic cells. To identify aberrant tyrosine kinase or phosphatase activity in the various types of acute lymphoblastic leukemia is of great interest since enzymes in general make good targets for drugs. A novel SH2 domain binding approach is presented which can detect distinctive profiles of tyrosine-phosphorylated proteins in complex mixtures of cellular proteins. A battery of SH2 domains is employed as probes in a competitive far-Western blot based assay to identify specific tyrosine-phosphorylated sites which reflect active signaling pathways in a cell. A further refinement of this technology is under way with DNA-tagged probes being developed which allow for multiplexing and high throughput quantitative assessment of SH2-domain binding by quantitative PCR or microarray technologies.
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23

Waksman, Gabriel, Sangaralingam Kumaran, and Olga Lubman. "SH2 domains: role, structure and implications for molecular medicine." Expert Reviews in Molecular Medicine 6, no. 3 (January 30, 2004): 1–18. http://dx.doi.org/10.1017/s1462399404007331.

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Src homology 2 (SH2) domains are protein modules (of ~100 amino acids) found in many proteins involved in tyrosine kinase signalling cascades. Their function is to bind tyrosine-phosphorylated sequences in specific protein targets. Binding of an SH2 domain to its cognate tyrosine-phosphorylated target links receptor activation to downstream signalling, both to the nucleus to regulate gene expression and throughout the cytoplasm of the cell. This review recapitulates the roles that SH2 domains play in normal and diseased states, describes the successes of SH2 domain research in deciphering their mechanism of action, and provides an overview of the use of SH2 domains as structural templates for the design of inhibitor drugs.
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24

Yogo, Keiichiro, Megumi Mizutamari, Kazuta Mishima, Hiromi Takenouchi, Norihiro Ishida-Kitagawa, Takehiko Sasaki, and Tatsuo Takeya. "Src Homology 2 (SH2)-Containing 5′-Inositol Phosphatase Localizes to Podosomes, and the SH2 Domain Is Implicated in the Attenuation of Bone Resorption in Osteoclasts." Endocrinology 147, no. 7 (July 1, 2006): 3307–17. http://dx.doi.org/10.1210/en.2005-1309.

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c-Src plays an important role in bone resorption by osteoclasts. Here, we show using wild-type and ship−/− osteoclasts that Src homology 2 (SH2)-containing 5′-inositol phosphatase (SHIP) appeared to negatively regulate bone resorption activated by c-Src. SHIP was found to localize to podosomes under the influence of c-Src, and the presence of either the amino-terminal region comprising the SH2 domain or the carboxyl-terminal region was sufficient for its localization. Although SHIP lacking a functional SH2 domain was still found in podosomes, it could not rescue the hyper-bone resorbing activity and hypersensitivity to receptor activator of nuclear factor-κB ligand in ship−/− osteoclasts, suggesting that the localization of SHIP to podosomes per se was not sufficient and the SH2 domain was indispensable for its function. Cas and c-Cbl, known to function in podosomes of osteoclasts, were identified as novel proteins binding to the SHIP SH2 domain by mass spectrometric analysis, and this interaction appeared to be dependent on the Src kinase activity. These results demonstrate that c-Src enhances the translocation of SHIP to podosomes and regulates its function there through the SH2 domain, leading to an attenuation of bone resorption.
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25

Tridandapani, Susheela, Madhura Pradhan, James R. LaDine, Stacey Garber, Clark L. Anderson, and K. Mark Coggeshall. "Protein Interactions of Src Homology 2 (SH2) Domain-Containing Inositol Phosphatase (SHIP): Association with Shc Displaces SHIP from FcγRIIb in B Cells." Journal of Immunology 162, no. 3 (February 1, 1999): 1408–14. http://dx.doi.org/10.4049/jimmunol.162.3.1408.

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Abstract Our recent studies revealed that the inositol phosphatase Src homology 2 (SH2) domain-containing inositol phosphatase (SHIP) is phosphorylated and associated with Shc exclusively under negative signaling conditions in B cells, which is due to recruitment of the SHIP SH2 domain to the FcγRIIb. In addition, we reported that SHIP-Shc interaction involves both SHIP SH2 and Shc phosphotyrosine binding domains. These findings reveal a paradox in which the single SH2 domain of SHIP is simultaneously engaged to two different proteins: Shc and FcγRIIb. To resolve this paradox, we examined the protein interactions of SHIP. Our results demonstrated that isolated FcγRIIb contains SHIP but not Shc; likewise, Shc isolates contain SHIP but not FcγRIIb. In contrast, SHIP isolates contain both proteins, revealing two separate pools of SHIP: one bound to FcγRIIb and one bound to Shc. Kinetic studies reveal rapid SHIP association with FcγRIIb but slower and more transient association with Shc. Affinity measurements using a recombinant SHIP SH2 domain and phosphopeptides derived from FcγRIIb (corresponding to Y273) and Shc (corresponding to Y317) revealed an approximately equal rate of binding but a 10-fold faster dissociation rate for FcγRIIb compared with Shc phosphopeptide and yielding in an affinity of 2.1 μM for FcγRIIb and 0.26 μM for Shc. These findings are consistent with a model in which SHIP transiently associates with FcγRIIb to promote SHIP phosphorylation, whereupon SHIP binds to Shc and dissociates from FcγRIIb.
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26

RIORDAN, Stephen M., Sukhwinderjit LIDDER, Roger WILLIAMS, and George G. SKOUTERIS. "The β-subunit of the hepatocyte growth factor/scatter factor (HGF/SF) receptor phosphorylates and associates with CrkII: expression of CrkII enhances HGF/SF-induced mitogenesis." Biochemical Journal 350, no. 3 (September 8, 2000): 925–32. http://dx.doi.org/10.1042/bj3500925.

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CrkII, a 40kDa adaptor possessing a Src homology (SH)2 domain followed by two SH3 domains, although not endowed with catalytic activity, participates in intracellular signalling, presumably by activating the Ras pathway. CrkII was found to be phosphorylated in response to hepatocyte growth factor/scatter factor (HGF/SF) and to associate with the beta-subunit of the HGF receptor (MET). CrkII associated with p145βMET via its SH2 domain. Growth-factor-receptor-bound protein 2 (Grb2) co-immunoprecipitated with CrkII species. By transient transfection of A431 human epidermoid carcinoma cells with wild-type and dominant-negative Grb2 expression constructs lacking either the SH2 or SH3 domains, we have concluded that Grb2 does not contribute to the ‘presentation’ of CrkII to p145βMET. Overexpression of wild-type CrkII in A431 cells enhanced HGF/SF-induced proliferation, while a CrkII dominant-negative mutant lacking the SH2 domain prevented a similar proliferating response to HGF/SF. The effect of CrkII on HGF/SF-induced proliferation was also abolished in cells co-expressing CrkII and Son-of-sevenless lacking the guanine exchange domain, suggesting that CrkII is likely to induce cell proliferation partly via the Ras/mitogen-activated protein kinase route.
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27

Meng, Li, JinPing Luo, Chunhua Li, and William H. Kinsey. "Role of Src homology 2 domain-mediated PTK signaling in mouse zygotic development." Reproduction 132, no. 3 (September 2006): 413–21. http://dx.doi.org/10.1530/rep.1.01151.

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Fyn and other Src-family kinases play an essential role at several steps during egg activation following fertilization of externally fertilizing species, such as marine invertebrates, fish, and frogs. Recent studies demonstrate that the requirement for Src-family kinases in activation of the mammalian egg is different from lower species, and the objective of this study was to test the role of the Fyn kinase in the mouse egg activated by intracytoplasmic sperm injection (ICSI). An Src homology 2 (SH2) domain containing fusion protein was used to suppress Fyn function in the mouse zygote following ICSI. Eggs injected with the Fyn SH2 domain at an intracellular concentration of 4–8 μM exhibited reduced developmental potential with 100% of the zygotes being arrested following the first or the second cleavage. At higher concentrations, the protein blocked pronuclear congression and the zygotes remained at the pronuclear stage. The SH2 domain had no effect on sperm-induced calcium oscillations in distinct contrast to its effect on the eggs of lower species. The results indicate that the SH2 domain of Fyn kinase plays an important role in pronuclear congression as well as early cleavage events and that this effect appears not to involve disruption of calcium oscillations.
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28

de Araujo, Elvin D., Anna Orlova, Heidi A. Neubauer, Dávid Bajusz, Hyuk-Soo Seo, Sirano Dhe-Paganon, György M. Keserű, Richard Moriggl, and Patrick T. Gunning. "Structural Implications of STAT3 and STAT5 SH2 Domain Mutations." Cancers 11, no. 11 (November 8, 2019): 1757. http://dx.doi.org/10.3390/cancers11111757.

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Src Homology 2 (SH2) domains arose within metazoan signaling pathways and are involved in protein regulation of multiple pleiotropic cascades. In signal transducer and activator of transcription (STAT) proteins, SH2 domain interactions are critical for molecular activation and nuclear accumulation of phosphorylated STAT dimers to drive transcription. Sequencing analysis of patient samples has revealed the SH2 domain as a hotspot in the mutational landscape of STAT proteins although the functional impact for the vast majority of these mutations remains poorly characterized. Despite several well resolved structures for SH2 domain-containing proteins, structural data regarding the distinctive STAT-type SH2 domain is limited. Here, we review the unique features of STAT-type SH2 domains in the context of all currently reported STAT3 and STAT5 SH2 domain clinical mutations. The genetic volatility of specific regions in the SH2 domain can result in either activating or deactivating mutations at the same site in the domain, underscoring the delicate evolutionary balance of wild type STAT structural motifs in maintaining precise levels of cellular activity. Understanding the molecular and biophysical impact of these disease-associated mutations can uncover convergent mechanisms of action for mutations localized within the STAT SH2 domain to facilitate the development of targeted therapeutic interventions.
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29

Dombrosky-Ferlan, Patrice, Anatoly Grishin, Roberto J. Botelho, Matthew Sampson, Lin Wang, William A. Rudert, Sergio Grinstein, and Seth J. Corey. "Felic (CIP4b), a novel binding partner with the Src kinase Lyn and Cdc42, localizes to the phagocytic cup." Blood 101, no. 7 (April 1, 2003): 2804–9. http://dx.doi.org/10.1182/blood-2002-03-0851.

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Through its Src homology 3 (SH3) and SH2 domains, the Src kinase Lyn interacts with a small number of phosphoproteins, such as Shc, Cbl, and Vav, which regulate cell cycle and the cytoskeleton. Using Lyn's Unique, SH3, and SH2 domains as bait in a yeast 2–hybrid screen, we isolated a novel gene product with features of a scaffolding protein. We named it Felic because it contains a domain homologous to the tyrosine kinase Fes and the cytoskeletal proteinezrin and forms a Lyn interaction with the GTPase Cdc42 (Felic). Felic was expressed in both hematopoietic and nonhematopoietic tissues. Because it represents an alternative splice product related to the Cdc42-interacting protein 4, CIP4, we also refer to Felic as CIP4b. Felic contains an SH3 recognition site RXPXXP and multiple tyrosine residues. In insulin or serum-stimulated HEK293 cells, Felic became tyrosine phosphorylated. Like CIP4, Felic associated with Cdc42 in its activated form only. Unlike CIP4, Felic does not possess a C-terminal SH3 domain. Coprecipitation studies show that Felic bound to Lyn or activated forms of Cdc42. Overexpression of Felic or CIP4 inhibited NIH 3T3 cell invasiveness in a Matrigel assay. Because Lyn and Cdc42 are involved in phagocytosis, we examined the distribution of Felic in RAW macrophages during particle ingestion. Felic was recruited more efficiently than CIP4 to the phagocytic cups. Altogether, these data suggest that CIP4/Felic constitute a novel family of cytoskeletal scaffolding proteins, integrating Src and Cdc42 pathways. The absence of an SH3 domain in Felic provides a structural basis for functional differences.
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30

KOTANI, Kei, Peter WILDEN, and Tahir S. PILLAY. "SH2-Bα is an insulin-receptor adapter protein and substrate that interacts with the activation loop of the insulin-receptor kinase." Biochemical Journal 335, no. 1 (October 1, 1998): 103–9. http://dx.doi.org/10.1042/bj3350103.

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We identified SH2-Bα as an insulin-receptor-binding protein based on interaction screening in yeast hybrid systems and co-precipitation in cells. SH2-Bα contains pleckstrin-homology (‘PH’) and Src homology 2 (SH2) domains and is closely related to APS (adapter protein with a PH domain and an SH2 domain) and lnk, adapter proteins first identified in lymphocytes. SH2-Bα is ubiquitously expressed and is present in rat epididymal adipose tissue, liver and skeletal muscle, physiological sites of insulin action. On SDS/PAGE, SH2-Bα migrates at a molecular mass of 98 kDa, although the predicted size of SH2-Bα is 79.6 kDa. Insulin causes an electrophoretic mobility shift. SH2-Bα can be immunoprecipitated using anti-(insulin receptor) antibody from insulin-stimulated cells. Anti-phosphotyrosine antibody or the growth factor receptor-binding protein 2 (Grb2) SH2 domain precipitate SH2-Bα after insulin stimulation, suggesting that SH2-Bα is tyrosine-phosphorylated and may be a substrate for the insulin receptor. The SH2-Bα SH2 domain did not interact with insulin-receptor substrate (IRS) proteins or epidermal-growth-factor receptor. Mutation of the juxtamembrane and C-terminus of the insulin receptor did not abolish the interaction with the SH2 domain. This was further confirmed using a panel of activation-loop single point mutants where mutation of Tyr1158, Tyr1162 and Tyr1163 abolished interaction. Thus SH2-Bα is a likely component in the insulin-signalling pathway and may function as an alternative signalling protein by interacting with the activation loop of the insulin-receptor cytoplasmic domain.
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31

Tu, Yizeng, Fugang Li, and Chuanyue Wu. "Nck-2, a Novel Src Homology2/3-containing Adaptor Protein That Interacts with the LIM-only Protein PINCH and Components of Growth Factor Receptor Kinase-signaling Pathways." Molecular Biology of the Cell 9, no. 12 (December 1998): 3367–82. http://dx.doi.org/10.1091/mbc.9.12.3367.

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Many of the protein–protein interactions that are essential for eukaryotic intracellular signal transduction are mediated by protein binding modules including SH2, SH3, and LIM domains. Nck is a SH3- and SH2-containing adaptor protein implicated in coordinating various signaling pathways, including those of growth factor receptors and cell adhesion receptors. We report here the identification, cloning, and characterization of a widely expressed, Nck-related adaptor protein termed Nck-2. Nck-2 comprises primarily three N-terminal SH3 domains and one C-terminal SH2 domain. We show that Nck-2 interacts with PINCH, a LIM-only protein implicated in integrin-linked kinase signaling. The PINCH-Nck-2 interaction is mediated by the fourth LIM domain of PINCH and the third SH3 domain of Nck-2. Furthermore, we show that Nck-2 is capable of recognizing several key components of growth factor receptor kinase-signaling pathways including EGF receptors, PDGF receptor-β, and IRS-1. The association of Nck-2 with EGF receptors was regulated by EGF stimulation and involved largely the SH2 domain of Nck-2, although the SH3 domains of Nck-2 also contributed to the complex formation. The association of Nck-2 with PDGF receptor-β was dependent on PDGF activation and was mediated solely by the SH2 domain of Nck-2. Additionally, we have detected a stable association between Nck-2 and IRS-1 that was mediated primarily via the second and third SH3 domain of Nck-2. Thus, Nck-2 associates with PINCH and components of different growth factor receptor-signaling pathways via distinct mechanisms. Finally, we provide evidence indicating that a fraction of the Nck-2 and/or Nck-1 proteins are associated with the cytoskeleton. These results identify a novel Nck-related SH2- and SH3-domain–containing protein and suggest that it may function as an adaptor protein connecting the growth factor receptor-signaling pathways with the integrin-signaling pathways.
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32

Muller, A. J., J. C. Young, A. M. Pendergast, M. Pondel, N. R. Landau, D. R. Littman, and O. N. Witte. "BCR first exon sequences specifically activate the BCR/ABL tyrosine kinase oncogene of Philadelphia chromosome-positive human leukemias." Molecular and Cellular Biology 11, no. 4 (April 1991): 1785–92. http://dx.doi.org/10.1128/mcb.11.4.1785-1792.1991.

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The c-abl proto-oncogene encodes a cytoplasmic tyrosine kinase which is homologous to the src gene product in its kinase domain and in the upstream kinase regulatory domains SH2 (src homology region 2) and SH3 (src homology region 3). The murine v-abl oncogene product has lost the SH3 domain as a consequence of N-terminal fusion of gag sequences. Deletion of the SH3 domain is sufficient to render the murine c-abl proto-oncogene product transforming when myristylated N-terminal membrane localization sequences are also present. In contrast, the human BCR/ABL oncogene of the Philadelphia chromosome translocation has an intact SH3 domain and its product is not myristylated at the N terminus. To analyze the contribution of BCR-encoded sequences to BCR/ABL-mediated transformation, the effects of a series of deletions and substitutions were assessed in fibroblast and hematopoietic-cell transformation assays. BCR first-exon sequences specifically potentiate transformation and tyrosine kinase activation when they are fused to the second exon of otherwise intact c-ABL. This suggests that BCR-encoded sequences specifically interfere with negative regulation of the ABL-encoded tyrosine kinase, which would represent a novel mechanism for the activation of nonreceptor tyrosine kinase-encoding proto-oncogenes.
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33

Muller, A. J., J. C. Young, A. M. Pendergast, M. Pondel, N. R. Landau, D. R. Littman, and O. N. Witte. "BCR first exon sequences specifically activate the BCR/ABL tyrosine kinase oncogene of Philadelphia chromosome-positive human leukemias." Molecular and Cellular Biology 11, no. 4 (April 1991): 1785–92. http://dx.doi.org/10.1128/mcb.11.4.1785.

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The c-abl proto-oncogene encodes a cytoplasmic tyrosine kinase which is homologous to the src gene product in its kinase domain and in the upstream kinase regulatory domains SH2 (src homology region 2) and SH3 (src homology region 3). The murine v-abl oncogene product has lost the SH3 domain as a consequence of N-terminal fusion of gag sequences. Deletion of the SH3 domain is sufficient to render the murine c-abl proto-oncogene product transforming when myristylated N-terminal membrane localization sequences are also present. In contrast, the human BCR/ABL oncogene of the Philadelphia chromosome translocation has an intact SH3 domain and its product is not myristylated at the N terminus. To analyze the contribution of BCR-encoded sequences to BCR/ABL-mediated transformation, the effects of a series of deletions and substitutions were assessed in fibroblast and hematopoietic-cell transformation assays. BCR first-exon sequences specifically potentiate transformation and tyrosine kinase activation when they are fused to the second exon of otherwise intact c-ABL. This suggests that BCR-encoded sequences specifically interfere with negative regulation of the ABL-encoded tyrosine kinase, which would represent a novel mechanism for the activation of nonreceptor tyrosine kinase-encoding proto-oncogenes.
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34

Schlaepfer, D. D., M. A. Broome, and T. Hunter. "Fibronectin-stimulated signaling from a focal adhesion kinase-c-Src complex: involvement of the Grb2, p130cas, and Nck adaptor proteins." Molecular and Cellular Biology 17, no. 3 (March 1997): 1702–13. http://dx.doi.org/10.1128/mcb.17.3.1702.

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The focal adhesion kinase (FAK), a protein-tyrosine kinase (PTK), associates with integrin receptors and is activated by cell binding to extracellular matrix proteins, such as fibronectin (FN). FAK autophosphorylation at Tyr-397 promotes Src homology 2 (SH2) domain binding of Src family PTKs, and c-Src phosphorylation of FAK at Tyr-925 creates an SH2 binding site for the Grb2 SH2-SH3 adaptor protein. FN-stimulated Grb2 binding to FAK may facilitate intracellular signaling to targets such as ERK2-mitogen-activated protein kinase. We examined FN-stimulated signaling to ERK2 and found that ERK2 activation was reduced 10-fold in Src- fibroblasts, compared to that of Src- fibroblasts stably reexpressing wild-type c-Src. FN-stimulated FAK phosphotyrosine (P.Tyr) and Grb2 binding to FAK were reduced, whereas the tyrosine phosphorylation of another signaling protein, p130cas, was not detected in the Src- cells. Stable expression of residues 1 to 298 of Src (Src 1-298, which encompass the SH3 and SH2 domains of c-Src) in the Src- cells blocked Grb2 binding to FAK; but surprisingly, Src 1-298 expression also resulted in elevated p130cas P.Tyr levels and a two- to threefold increase in FN-stimulated ERK2 activity compared to levels in Src- cells. Src 1-298 bound to both FAK and p130cas and promoted FAK association with p130cas in vivo. FAK was observed to phosphorylate p130cas in vitro and could thus phosphorylate p130cas upon FN stimulation of the Src 1-298-expressing cells. FAK-induced phosphorylation of p130cas in the Src 1-298 cells promoted the SH2 domain-dependent binding of the Nck adaptor protein to p130cas, which may facilitate signaling to ERK2. These results show that there are additional FN-stimulated pathways to ERK2 that do not involve Grb2 binding to FAK.
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35

Ju, Tong, Wei Niu, and Jiantao Guo. "Evolution of Src Homology 2 (SH2) Domain to Recognize Sulfotyrosine." ACS Chemical Biology 11, no. 9 (July 21, 2016): 2551–57. http://dx.doi.org/10.1021/acschembio.6b00555.

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36

Cooper, J. A., and A. Kashishian. "In vivo binding properties of SH2 domains from GTPase-activating protein and phosphatidylinositol 3-kinase." Molecular and Cellular Biology 13, no. 3 (March 1993): 1737–45. http://dx.doi.org/10.1128/mcb.13.3.1737-1745.1993.

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We have used a transient expression system and mutant platelet-derived growth factor (PDGF) receptors to study the binding specificities of the Src homology 2 (SH2) regions of the Ras GTPase-activator protein (GAP) and the p85 alpha subunit of phosphatidylinositol 3-kinase (PI3 kinase). A number of fusion proteins, each tagged with an epitope allowing recognition by a monoclonal antibody, were expressed at levels comparable to those of endogenous GAP. Fusion proteins containing the central SH2-SH3-SH2 region of GAP or the C-terminal region of p85 alpha, which includes two SH2 domains, bound to PDGF receptors in response to PDGF stimulation. Both fusion proteins showed the same requirements for tyrosine phosphorylation sites in the PDGF receptor as the full-length proteins from which they were derived, i.e., binding of the GAP fusion protein was reduced by mutation of Tyr-771, and binding of the p85 fusion protein was reduced by mutation of Tyr-740, Tyr-751, or both residues. Fusion proteins containing single SH2 domains from either GAP or p85 alpha did not bind detectably to PDGF receptors in this system, suggesting that two SH2 domains in a single polypeptide cooperate to raise the affinity of binding. The sequence specificities of individual SH2 domains were deduced from the binding properties of fusion proteins containing one SH2 domain from GAP and another from p85. The results suggest that the C-terminal GAP SH2 domain specifies binding to Tyr-771, the C-terminal p85 alpha SH2 domain binds to either Tyr-740 or Tyr-751, and each protein's N-terminal SH2 domain binds to unidentified phosphorylation sites.(ABSTRACT TRUNCATED AT 250 WORDS)
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37

Cooper, J. A., and A. Kashishian. "In vivo binding properties of SH2 domains from GTPase-activating protein and phosphatidylinositol 3-kinase." Molecular and Cellular Biology 13, no. 3 (March 1993): 1737–45. http://dx.doi.org/10.1128/mcb.13.3.1737.

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We have used a transient expression system and mutant platelet-derived growth factor (PDGF) receptors to study the binding specificities of the Src homology 2 (SH2) regions of the Ras GTPase-activator protein (GAP) and the p85 alpha subunit of phosphatidylinositol 3-kinase (PI3 kinase). A number of fusion proteins, each tagged with an epitope allowing recognition by a monoclonal antibody, were expressed at levels comparable to those of endogenous GAP. Fusion proteins containing the central SH2-SH3-SH2 region of GAP or the C-terminal region of p85 alpha, which includes two SH2 domains, bound to PDGF receptors in response to PDGF stimulation. Both fusion proteins showed the same requirements for tyrosine phosphorylation sites in the PDGF receptor as the full-length proteins from which they were derived, i.e., binding of the GAP fusion protein was reduced by mutation of Tyr-771, and binding of the p85 fusion protein was reduced by mutation of Tyr-740, Tyr-751, or both residues. Fusion proteins containing single SH2 domains from either GAP or p85 alpha did not bind detectably to PDGF receptors in this system, suggesting that two SH2 domains in a single polypeptide cooperate to raise the affinity of binding. The sequence specificities of individual SH2 domains were deduced from the binding properties of fusion proteins containing one SH2 domain from GAP and another from p85. The results suggest that the C-terminal GAP SH2 domain specifies binding to Tyr-771, the C-terminal p85 alpha SH2 domain binds to either Tyr-740 or Tyr-751, and each protein's N-terminal SH2 domain binds to unidentified phosphorylation sites.(ABSTRACT TRUNCATED AT 250 WORDS)
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38

Verderame, M. F. "pp60v-src transformation of rat cells but not chicken cells strongly correlates with low-affinity phosphopeptide binding by the SH2 domain." Molecular Biology of the Cell 8, no. 5 (May 1997): 843–54. http://dx.doi.org/10.1091/mbc.8.5.843.

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Substrates critical for transformation by pp60v-src remain unknown, as does the precise role of the src homology 2 (SH2) domain in this process. To continue exploring the role of the SH2 domain in pp60v-src-mediated transformation, site-directed mutagenesis was used to create mutant v-src alleles predicted to encode proteins with overall structural integrity intact but with reduced ability to bind phosphotyrosine-containing peptides. Arginine-175, which makes critical contacts in the phosphotyrosine-binding pocket, was mutated to lysine or alanine. Unexpectedly, both mutations created v-src alleles that transform chicken cells with wild-type (wt) efficiency and are reduced for transformation of rat cells; these alleles are host dependent for transformation. Additionally, these alleles resulted in a round morphological transformation of chicken cells, unlike 12 of the 13 known host-dependent src SH2 mutations that result in a fusiform morphology. Analysis of phosphopeptide binding by the mutant SH2 domains reveal that the in vitro ability to bind phosphopeptides known to have a high affinity for wt src SH2 correlates with wt (round) morphological transformation in chicken cells and in vitro ability to bind phosphopeptides known to have a low affinity for wt src SH2 correlates with rat cell transformation. These results suggest that the search for critical substrates in rat cells should be among proteins that interact with pp60v-src with low affinity.
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39

WARNER, Andrea J., Jennifer LOPEZ-DEE, Emma L. KNIGHT, James R. FERAMISCO, and Sally A. PRIGENT. "The Shc-related adaptor protein, Sck, forms a complex with the vascular-endothelial-growth-factor receptor KDR in transfected cells." Biochemical Journal 347, no. 2 (April 10, 2000): 501–9. http://dx.doi.org/10.1042/bj3470501.

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Despite much progress in recent years, the precise signalling events triggered by the vascular-endothelial-growth-factor (VEGF) receptors, fms-like tyrosine kinase (Flt1) and kinase insert domain-containing receptor (KDR), are incompletely defined. Results obtained when Flt1 and KDR are individually expressed in fibroblasts or porcine aortic endothelial cells have not been entirely consistent with those observed in other endothelial cells expressing both receptors endogenously. It has also been difficult to demonstrate VEGF-induced phosphorylation of Flt1, which has led to speculation that KDR may be the more important receptor for the mitogenic action of VEGF on endothelial cells. In an attempt to identify physiologically important effectors which bind to KDR, we have screened a yeast two-hybrid mouse embryo library with the cytoplasmic domain of KDR. Here we describe the identification of the adaptor protein, Shc-like protein (Sck), as a binding partner for KDR. We demonstrate that this interaction requires phosphorylation of KDR, and identify the binding site for the Src-homology 2 (SH2) domain as tyrosine-1175 of KDR. We have also shown that the SH2 domain of Sck, but not that of Src-homology collagen protein (Shc), can precipitate phosphorylated KDR from VEGF-stimulated porcine aortic endothelial cells expressing KDR, and that an N-terminally truncated Sck protein can associate with KDR, in a phosphorylation-dependent fashion, when co-expressed in human embryonic kidney 293 cells. Furthermore, we demonstrate that in the two-hybrid assay, both Shc and Sck SH2 domains can associate with the related receptor Flt1.
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40

SACI, Abdelhafid, Wang-Qing LIU, Michel VIDAL, Christiane GARBAY, Francine RENDU, and Christilla BACHELOT-LOZA. "Differential effect of the inhibition of Grb2–SH3 interactions in platelet activation induced by thrombin and by Fc receptor engagement." Biochemical Journal 363, no. 3 (April 24, 2002): 717–25. http://dx.doi.org/10.1042/bj3630717.

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The adaptor protein Grb2 (growth factor receptor-bound protein 2) is involved in cell proliferation via the Ras signalling pathway. In order to study the role of Grb2 in blood platelet responses, we used a peptide containing two proline-rich sequences derived from Sos (peptidimer), which binds to Grb2—Src homology 3 domain (SH3) with a high affinity, and hence inhibits Grb2—SH3-mediated protein interactions. Platelet aggregation and 5-hydroxytryptamine (serotonin) release measured in the presence of the peptidimer were: (i) significantly decreased when induced by thrombin; and (ii) potentiated when induced by the engagement of the Fc receptor. In thrombin-activated platelets, the Grb2—SH2 domain formed an association with the β3 subunit of the αIIb—β3 integrin (GPIIb—IIIa), Shc, Syk, Src and SHP1 (SH2-containing phosphotyrosine phosphatase 1), whereas these associations did not occur after the engagement of the receptor for the Fc domain of IgG (FcγRIIa) or in resting platelets. Grb2—SH3 domains formed an association with the proline-rich sequences of Sos and Cbl in both resting and activated platelets, since the peptidimer abolished these associations. Inhibition of both fibrinogen binding and platelet aggregation by the peptide RGDS (Arg-Gly-Asp-Ser) had no effect on thrombin-induced Grb2—SH2 domain association with the aforementioned signalling molecules, indicating that these associations occurred during thrombin-induced ‘inside-out’ signalling. Platelet aggregation induced by direct activation via αIIb—β3 ('outside-in’ signalling) was potentiated by the peptidimer. The results show that inhibition of Grb2—SH3 interactions with signal-transduction proteins down-regulates thrombin-induced platelet activation, but also potentiates Fc receptor- and αIIb—β3-mediated platelet activation.
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41

Takagi, Norio, Herman H. Cheung, Nankie Bissoon, Lucy Teves, M. Christopher Wallace, and James W. Gurd. "The Effect of Transient Global Ischemia on the Interaction of Src and Fyn with the N-Methyl-d-Aspartate Receptor and Postsynaptic Densities: Possible Involvement of Src Homology 2 Domains." Journal of Cerebral Blood Flow & Metabolism 19, no. 8 (August 1999): 880–88. http://dx.doi.org/10.1097/00004647-199908000-00007.

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Transient ischemia increases tyrosine phosphorylation of N-methyl-d-aspartate (NMDA) receptor subunits NR2A and NR2B in the rat hippocampus. The authors investigated the effects of this increase on the ability of the receptor subunits to bind to the Src homology 2 (SH2) domains of Src and Fyn expressed as glutathione-S-transferase–SH2 fusion proteins. The NR2A and NR2B bound to each of the SH2 domains and binding was increased approximately twofold after ischemia and reperfusion. Binding was prevented by prior incubation of hippocampal homogenates with a protein tyrosine phosphatase or by a competing peptide for the Src SH2 domain. Ischemia induced a marked increase in the tyrosine phosphorylation of several proteins in the postsynaptic density (PSD), including NR2A and NR2B, but had no effect on the amounts of individual NMDA receptor subunits in the PSD. The level of Src and Fyn in PSDs, but not in other subcellular fractions, was increased after ischemia. The ischemia-induced increase in the interaction of NR2A and NR2B with the SH2 domains of Src and Fyn suggests a possible mechanism for the recruitment of signaling proteins to the PSD and may contribute to altered signal transduction in the postischemic hippocampus.
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42

Fujioka, Y., T. Matozaki, T. Noguchi, A. Iwamatsu, T. Yamao, N. Takahashi, M. Tsuda, T. Takada, and M. Kasuga. "A novel membrane glycoprotein, SHPS-1, that binds the SH2-domain-containing protein tyrosine phosphatase SHP-2 in response to mitogens and cell adhesion." Molecular and Cellular Biology 16, no. 12 (December 1996): 6887–99. http://dx.doi.org/10.1128/mcb.16.12.6887.

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Protein tyrosine phosphatases (PTPases), such as SHP-1 and SHP-2, that contain Src homology 2 (SH2) domains play important roles in growth factor and cytokine signal transduction pathways. A protein of approximately 115 to 120 kDa that interacts with SHP-1 and SHP-2 was purified from v-src-transformed rat fibroblasts (SR-3Y1 cells), and the corresponding cDNA was cloned. The predicted amino acid sequence of the encoded protein, termed SHPS-1 (SHP substrate 1), suggests that it is a glycosylated receptor-like protein with three immunoglobulin-like domains in its extracellular region and four YXX(L/V/I) motifs, potential tyrosine phosphorylation and SH2-domain binding sites, in its cytoplasmic region. Various mitogens, including serum, insulin, and lysophosphatidic acid, or cell adhesion induced tyrosine phosphorylation of SHPS-1 and its subsequent association with SHP-2 in cultured cells. Thus, SHPS-1 may be a direct substrate for both tyrosine kinases, such as the insulin receptor kinase or Src, and a specific docking protein for SH2-domain-containing PTPases. In addition, we suggest that SHPS-1 may be a potential substrate for SHP-2 and may function in both growth factor- and cell adhesion-induced cell signaling.
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43

DeBell, Karen, Laurie Graham, Ilona Reischl, Carmen Serrano, Ezio Bonvini, and Barbara Rellahan. "Intramolecular Regulation of Phospholipase C-γ1 by Its C-Terminal Src Homology 2 Domain." Molecular and Cellular Biology 27, no. 3 (November 20, 2006): 854–63. http://dx.doi.org/10.1128/mcb.01400-06.

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ABSTRACT Phosphoinositide-specific phospholipase C-γ1 (PLC-γ1) is a key enzyme that governs cellular functions such as gene transcription, secretion, proliferation, motility, and development. Here, we show that PLC-γ1 is regulated via a novel autoinhibitory mechanism involving its carboxy-terminal Src homology (SH2C) domain. Mutation of the SH2C domain tyrosine binding site led to constitutive PLC-γ1 activation. The amino-terminal split pleckstrin homology (sPHN) domain was found to regulate the accessibility of the SH2C domain. PLC-γ1 constructs with mutations in tyrosine 509 and phenylalanine 510 in the sPHN domain no longer required an intact amino-terminal Src homology (SH2N) domain or phosphorylation of tyrosine 775 or 783 for activation. These data are consistent with a model in which the SH2C domain is blocked by an intramolecular interaction(s) that is released upon cellular activation by occupancy of the SH2N domain.
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44

Visperas, Patrick R., Jonathan A. Winger, Timothy M. Horton, Neel H. Shah, Diane J. Aum, Alyssa Tao, Tiago Barros, et al. "Modification by covalent reaction or oxidation of cysteine residues in the tandem-SH2 domains of ZAP-70 and Syk can block phosphopeptide binding." Biochemical Journal 465, no. 1 (December 12, 2014): 149–61. http://dx.doi.org/10.1042/bj20140793.

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H2O2 and thiol-reactive inhibitors can attenuate the binding of the tandem-SH2 (Src-homology domain 2) domains of ζ-chain associated protein of 70 kDa (ZAP-70) and spleen tyrosine kinase (Syk) to doubly phosphorylated ITAM. This suggests a novel mechanism whereby oxidation of cysteine residues in these kinases could regulate immune cell signalling.
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45

Velazquez, Laura, Gerald D. Gish, Peter van der Geer, Lorne Taylor, Johanna Shulman, and Tony Pawson. "The Shc adaptor protein forms interdependent phosphotyrosine-mediated protein complexes in mast cells stimulated with interleukin 3." Blood 96, no. 1 (July 1, 2000): 132–38. http://dx.doi.org/10.1182/blood.v96.1.132.

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Abstract The Shc adaptor protein possesses 2 distinct phosphotyrosine (pTyr) recognition modules—the pTyr binding (PTB) domain and the Src homology 2 (SH2) domain—and multiple potential sites for tyrosine (Tyr) phosphorylation (Tyr residues 239, 240, and 317). On stimulation of hematopoietic cells with interleukin 3 (IL-3), Shc becomes phosphorylated and may therefore contribute to IL-3 signaling. We investigated the interactions mediated by the Shc modular domains and pTyr sites in IL-3–dependent IC2 premast cells. The Shc PTB domain, rather than the SH2 domain, associated both in vitro and in vivo with the Tyr-phosphorylated β subunit of the IL-3 receptor and with the SH2-containing 5′ inositol phosphatase (SHIP), and it recognized specific NXXpY phosphopeptides from these binding partners. In IL-3–stimulated mast cells, Shc phosphorylation occurred primarily on Tyr239 and 317 and was dependent on a functional PTB domain. Phosphorylated Tyr317, and to a lesser extent, Tyr239, bound the Grb2 adaptor and SHIP. Furthermore, a pTyr317 Shc phosphopeptide selectively recognized Grb2, Sos1, SHIP, and the p85 subunit of phosphatidylinositol 3′ kinase from mast cells, as characterized by mass spectrometry. These results indicate that Shc undergoes an interdependent series of pTyr-mediated interactions in IL-3–stimulated mast cells, resulting in the recruitment of proteins that regulate the Ras pathway and phospholipid metabolism.
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46

Velazquez, Laura, Gerald D. Gish, Peter van der Geer, Lorne Taylor, Johanna Shulman, and Tony Pawson. "The Shc adaptor protein forms interdependent phosphotyrosine-mediated protein complexes in mast cells stimulated with interleukin 3." Blood 96, no. 1 (July 1, 2000): 132–38. http://dx.doi.org/10.1182/blood.v96.1.132.013k13_132_138.

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The Shc adaptor protein possesses 2 distinct phosphotyrosine (pTyr) recognition modules—the pTyr binding (PTB) domain and the Src homology 2 (SH2) domain—and multiple potential sites for tyrosine (Tyr) phosphorylation (Tyr residues 239, 240, and 317). On stimulation of hematopoietic cells with interleukin 3 (IL-3), Shc becomes phosphorylated and may therefore contribute to IL-3 signaling. We investigated the interactions mediated by the Shc modular domains and pTyr sites in IL-3–dependent IC2 premast cells. The Shc PTB domain, rather than the SH2 domain, associated both in vitro and in vivo with the Tyr-phosphorylated β subunit of the IL-3 receptor and with the SH2-containing 5′ inositol phosphatase (SHIP), and it recognized specific NXXpY phosphopeptides from these binding partners. In IL-3–stimulated mast cells, Shc phosphorylation occurred primarily on Tyr239 and 317 and was dependent on a functional PTB domain. Phosphorylated Tyr317, and to a lesser extent, Tyr239, bound the Grb2 adaptor and SHIP. Furthermore, a pTyr317 Shc phosphopeptide selectively recognized Grb2, Sos1, SHIP, and the p85 subunit of phosphatidylinositol 3′ kinase from mast cells, as characterized by mass spectrometry. These results indicate that Shc undergoes an interdependent series of pTyr-mediated interactions in IL-3–stimulated mast cells, resulting in the recruitment of proteins that regulate the Ras pathway and phospholipid metabolism.
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47

Hirai, H., and H. E. Varmus. "Site-directed mutagenesis of the SH2- and SH3-coding domains of c-src produces varied phenotypes, including oncogenic activation of p60c-src." Molecular and Cellular Biology 10, no. 4 (April 1990): 1307–18. http://dx.doi.org/10.1128/mcb.10.4.1307-1318.1990.

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The products of the viral and cellular src genes, p60v-src and p60c-src, appear to be composed of multiple functional domains. Highly conserved regions called src homology 2 and 3 (SH2 and SH3), comprising amino acid residues 88 to 250, are believed to modulate the protein-tyrosine kinase activity present in the carboxy-terminal halves of the src proteins. To explore the functions of these regions more fully, we have made 34 site-directed mutations in a transformation-competent c-src gene encoding phenylalanine in place of tyrosine 527 (Y527F c-src). Twenty of the new mutations change only one or two amino acids, and the remainder delete small or large portions of the SH2-SH3 region. These mutant alleles have been incorporated into a replication-competent Rous sarcoma virus vector to examine the biochemical and biological properties of the mutant proteins after infection of chicken embryo fibroblasts. Four classes of mutant proteins were observed: class 1, mutants with only slight differences from the parental gene products; class 2, mutant proteins with diminished transforming and specific kinase activities; class 3, mutant proteins with normal or enhanced specific kinase activity but impaired biological activity, often as a consequence of instability; and class 4, mutant proteins with augmented biological and catalytic activities. In general, there was a strong correlation between total kinase activity (or amounts of intracellular phosphotyrosine-containing proteins) and transforming activity. Deletion mutations and some point mutations affecting residues 109 to 156 inhibited kinase and transforming functions, whereas deletions affecting residues 187 to 226 generally had positive effects on one or both of those functions, confirming that SH2-SH3 has complex regulatory properties. Five mutations that augmented the transforming and kinase activities of Y527F c-src [F172P, R175L, delta(198-205), delta(206-226), and delta(176-226)] conferred transformation competence on an otherwise normal c-src gene, indicating that mutations in SH2 (like previously described lesions in SH3, the kinase domain, and a carboxy-terminal inhibitory domain) can activate c-src.
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48

Hirai, H., and H. E. Varmus. "Site-directed mutagenesis of the SH2- and SH3-coding domains of c-src produces varied phenotypes, including oncogenic activation of p60c-src." Molecular and Cellular Biology 10, no. 4 (April 1990): 1307–18. http://dx.doi.org/10.1128/mcb.10.4.1307.

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The products of the viral and cellular src genes, p60v-src and p60c-src, appear to be composed of multiple functional domains. Highly conserved regions called src homology 2 and 3 (SH2 and SH3), comprising amino acid residues 88 to 250, are believed to modulate the protein-tyrosine kinase activity present in the carboxy-terminal halves of the src proteins. To explore the functions of these regions more fully, we have made 34 site-directed mutations in a transformation-competent c-src gene encoding phenylalanine in place of tyrosine 527 (Y527F c-src). Twenty of the new mutations change only one or two amino acids, and the remainder delete small or large portions of the SH2-SH3 region. These mutant alleles have been incorporated into a replication-competent Rous sarcoma virus vector to examine the biochemical and biological properties of the mutant proteins after infection of chicken embryo fibroblasts. Four classes of mutant proteins were observed: class 1, mutants with only slight differences from the parental gene products; class 2, mutant proteins with diminished transforming and specific kinase activities; class 3, mutant proteins with normal or enhanced specific kinase activity but impaired biological activity, often as a consequence of instability; and class 4, mutant proteins with augmented biological and catalytic activities. In general, there was a strong correlation between total kinase activity (or amounts of intracellular phosphotyrosine-containing proteins) and transforming activity. Deletion mutations and some point mutations affecting residues 109 to 156 inhibited kinase and transforming functions, whereas deletions affecting residues 187 to 226 generally had positive effects on one or both of those functions, confirming that SH2-SH3 has complex regulatory properties. Five mutations that augmented the transforming and kinase activities of Y527F c-src [F172P, R175L, delta(198-205), delta(206-226), and delta(176-226)] conferred transformation competence on an otherwise normal c-src gene, indicating that mutations in SH2 (like previously described lesions in SH3, the kinase domain, and a carboxy-terminal inhibitory domain) can activate c-src.
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49

Muller, A. J., A. M. Pendergast, M. H. Havlik, L. Puil, T. Pawson, and O. N. Witte. "A limited set of SH2 domains binds BCR through a high-affinity phosphotyrosine-independent interaction." Molecular and Cellular Biology 12, no. 11 (November 1992): 5087–93. http://dx.doi.org/10.1128/mcb.12.11.5087-5093.1992.

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SH2 (src homology region 2) domains are implicated in protein-protein interactions involved in signal transduction pathways. Isolated SH2 domains bind proteins that are tyrosine phosphorylated. A novel, phosphotyrosine-independent binding interaction between BCR, the Philadelphia chromosome breakpoint cluster region gene product, and the SH2 domain of its translocation partner c-ABL has recently been reported. We have examined the ability of additional SH2 domains to bind phosphotyrosine-free BCR and compared this with their ability to bind tyrosine-phosphorylated c-ABL 1b. Of 11 individual SH2 domains examined, 8 exhibited relatively high affinity for c-ABL 1b, whereas only 4 exhibited relatively high affinity for BCR. Binding of tyrosine-phosphorylated c-ABL 1b by the relatively high-affinity ABL and ARG SH2 domains was quantitatively analyzed, and equilibrium dissociation constants for both interactions were estimated to be in the range of 5 x 10(-7) M. The ABL SH2 domain exhibited relatively high affinity for phosphotyrosine-free BCR as well; however, this interaction appears to be about two orders of magnitude weaker than binding of tyrosine-phosphorylated c-ABL 1b. The ARG SH2 domain exhibited relatively weak affinity for BCR and was determined to bind about 10-fold less strongly than the ABL SH2 domain. The ABL and ARG SH2 domains differ by only 10 of 91 amino acids, and the substitution of ABL-specific amino acids into either the amino- or carboxy-terminal half of the ARG SH2 domain was found to increase its affinity for BCR. We discuss these results in terms of a model which has been proposed for peptide binding by class I histocompatibility glycoproteins.
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50

Muller, A. J., A. M. Pendergast, M. H. Havlik, L. Puil, T. Pawson, and O. N. Witte. "A limited set of SH2 domains binds BCR through a high-affinity phosphotyrosine-independent interaction." Molecular and Cellular Biology 12, no. 11 (November 1992): 5087–93. http://dx.doi.org/10.1128/mcb.12.11.5087.

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SH2 (src homology region 2) domains are implicated in protein-protein interactions involved in signal transduction pathways. Isolated SH2 domains bind proteins that are tyrosine phosphorylated. A novel, phosphotyrosine-independent binding interaction between BCR, the Philadelphia chromosome breakpoint cluster region gene product, and the SH2 domain of its translocation partner c-ABL has recently been reported. We have examined the ability of additional SH2 domains to bind phosphotyrosine-free BCR and compared this with their ability to bind tyrosine-phosphorylated c-ABL 1b. Of 11 individual SH2 domains examined, 8 exhibited relatively high affinity for c-ABL 1b, whereas only 4 exhibited relatively high affinity for BCR. Binding of tyrosine-phosphorylated c-ABL 1b by the relatively high-affinity ABL and ARG SH2 domains was quantitatively analyzed, and equilibrium dissociation constants for both interactions were estimated to be in the range of 5 x 10(-7) M. The ABL SH2 domain exhibited relatively high affinity for phosphotyrosine-free BCR as well; however, this interaction appears to be about two orders of magnitude weaker than binding of tyrosine-phosphorylated c-ABL 1b. The ARG SH2 domain exhibited relatively weak affinity for BCR and was determined to bind about 10-fold less strongly than the ABL SH2 domain. The ABL and ARG SH2 domains differ by only 10 of 91 amino acids, and the substitution of ABL-specific amino acids into either the amino- or carboxy-terminal half of the ARG SH2 domain was found to increase its affinity for BCR. We discuss these results in terms of a model which has been proposed for peptide binding by class I histocompatibility glycoproteins.
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