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1
Masnikosa, Romana, Anna Nikolic e Olgica Nedic. "Lectin-induced alterations of the interaction of insulin and insulin-like growth factor 1 receptors with their ligands". Journal of the Serbian Chemical Society 73, n. 8-9 (2008): 793–804. http://dx.doi.org/10.2298/jsc0809793m.
Testo completoAbstract (sommario):
In order to study whether the carbohydrate moieties of the human placental IGF-I receptor (IGF1R), IGF-II receptor (IGF2R) and insulin receptors (IRs) play a role in ligand binding, solubilised cell membrane preparations were incubated with 125I-labelled IGF-I, IGF-II and insulin in the presence of lectins with different sugar specificities. Three incubation procedures were tested: ligand-first, co-incubation and lectin-first incubation. Wheat germ agglutinin (WGA), concanavalin A (Con A) and phytohaemagglutinin (PHA) altered the binding of IGF-I and insulin to their high-affinity receptors in a lectin specific and dose-dependent manner, whereas these lectins did not affect the interaction of IGF-II with its receptor(s). Moreover, the same lectins either inhibited or enhanced IGF-I and insulin binding, depending on the incubation scheme. These results also suggest that IR-A and IR-B from human placenta might be differently glycosylated.
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Jégouzo, Sabine A. F., Conor Nelson, Thomas Hardwick, S. T. Angel Wong, Noel Kuan Kiat Lau, Gaik Kin Emily Neoh, Rocío Castellanos-Rueda et al. "Mammalian lectin arrays for screening host–microbe interactions". Journal of Biological Chemistry 295, n. 14 (24 febbraio 2020): 4541–55. http://dx.doi.org/10.1074/jbc.ra120.012783.
Testo completoAbstract (sommario):
Many members of the C-type lectin family of glycan-binding receptors have been ascribed roles in the recognition of microorganisms and serve as key receptors in the innate immune response to pathogens. Other mammalian receptors have become targets through which pathogens enter target cells. These receptor roles have often been documented with binding studies involving individual pairs of receptors and microorganisms. To provide a systematic overview of interactions between microbes and the large complement of C-type lectins, here we developed a lectin array and suitable protocols for labeling of microbes that could be used to probe this array. The array contains C-type lectins from cow, chosen as a model organism of agricultural interest for which the relevant pathogen–receptor interactions have not been previously investigated in detail. Screening with yeast cells and various strains of both Gram-positive and -negative bacteria revealed distinct binding patterns, which in some cases could be explained by binding to lipopolysaccharides or capsular polysaccharides, but in other cases they suggested the presence of novel glycan targets on many of the microorganisms. These results are consistent with interactions previously ascribed to the receptors, but they also highlight binding to additional sugar targets that have not previously been recognized. Our findings indicate that mammalian lectin arrays represent unique discovery tools for identifying both novel ligands and new receptor functions.
3
Upham, Jacqueline P., Danielle Pickett, Tatsuro Irimura, E. Margot Anders e Patrick C. Reading. "Macrophage Receptors for Influenza A Virus: Role of the Macrophage Galactose-Type Lectin and Mannose Receptor in Viral Entry". Journal of Virology 84, n. 8 (27 gennaio 2010): 3730–37. http://dx.doi.org/10.1128/jvi.02148-09.
Testo completoAbstract (sommario):
ABSTRACT Although sialic acid has long been recognized as the primary receptor determinant for attachment of influenza virus to host cells, the specific receptor molecules that mediate viral entry are not known for any cell type. For the infection of murine macrophages by influenza virus, our earlier study indicated involvement of a C-type lectin, the macrophage mannose receptor (MMR), in this process. Here, we have used direct binding techniques to confirm and characterize the interaction of influenza virus with the MMR and to seek additional macrophage surface molecules that may have potential as receptors for viral entry. We identified the macrophage galactose-type lectin (MGL) as a second macrophage membrane C-type lectin that binds influenza virus and is known to be endocytic. Binding of influenza virus to MMR and MGL occurred independently of sialic acid through Ca2+-dependent recognition of viral glycans by the carbohydrate recognition domains of the two lectins; influenza virus also bound to the sialic acid on the MMR. Multivalent ligands of the MMR and MGL inhibited influenza virus infection of macrophages in a manner that correlated with expression of these receptors on different macrophage populations. Influenza virus strain A/PR/8/34, which is poorly glycosylated and infects macrophages poorly, was not recognized by the C-type lectin activity of either the MMR or the MGL. We conclude that lectin-mediated interactions of influenza virus with the MMR or the MGL are required for the endocytic uptake of the virus into macrophages, and these lectins can thus be considered secondary or coreceptors with sialic acid for infection of this cell type.
4
Baricevic, Ivona, Ljiljana Vicovac-Panic, Vesna Marinovic e Margita Cuperlovic. "Investigations of asialoglycoprotein receptor glycosylation by lectin affinity methods". Journal of the Serbian Chemical Society 67, n. 5 (2002): 331–38. http://dx.doi.org/10.2298/jsc0205331b.
Testo completoAbstract (sommario):
The asialoglycoprotein receptor belongs to the family of calcium-dependent (C-type) animal lectins. The purified receptor is a glycoprotein in which 10 % of the dry weight consists of sialic acid, galactose, N-acetylglucosamine and mannose. The carbohydrate content of the asialoglycoprotein receptor was investigated by lectin affinity methods. The usefulness of plant lectin affinity methods in the characterization of the saccharide content of the asialoglycoprotein receptor, as an animal lectin, is demonstrated. RCA I ConA, PHA, SNA I and WGA showed greater affinity toward the asialoglycoprotein receptor, while PSL, AAA and PNA showed negligible interactions with the asialoglycoprotein receptor. The obtained results correlated well with the carbohydrate content of the asialoglycoprotein receptor as determined by chemical methods.
5
Karpova, I. S., I. M. Shuba, V. V. Lylo e O. Y. Glavatskyi. "Characteristics of lectin receptors on erythrocyte membranes of patients with glioblastoma". Faktori eksperimental'noi evolucii organizmiv 34 (25 settembre 2024): 165–69. http://dx.doi.org/10.7124/feeo.v34.1634.
Testo completoAbstract (sommario):
Aim. This work is devoted to the search the abnormalities of the receptor-lectin reactions associated with glioblastoma for diagnostic purposes. Methods. Red blood cell (RBC) specimens were taken from 22 persons distributed into the two cohorts: donors without an oncological diagnosis; patients with glioblastoma (GB). Panel of 9 commercial lectins (LECTINOTEST, Lviv, Ukraine) was used: ConA, WGA, PHA-P; PHA-E; PHA-L, SNA, VAA, STA, and LABA. Also the original lectin from persimmon sepals (named PSL) was used. It was obtained by isoelectric focusing and ammonium sulfate fractionation. Intensity of lectin-receptor interactions was determined in reaction of hemagglutination. Results. Тwo lectins showed some directed divergence in patients from donors. For wheat germ agglutinin (WGA) сhanges in the intensity of lectin-receptor binding were downward. In the case of persimmon L (PSL) the alternative result was observed: the intensity of hemagglutination showed a trend to exceed the level of control. Conclusions. Some individual features in the reaction of erythrocytes with a set of lectins are observed in all examined persons. For two studied lectins, namely WGA and PSL, unidirectional deviations were observed in the reaction of erythrocytes of patients with GB compared to individuals without an oncological diagnosis.
6
Hébert, Eric. "Endogenous Lectins as Cell Surface Transducers". Bioscience Reports 20, n. 4 (1 agosto 2000): 213–37. http://dx.doi.org/10.1023/a:1026484722248.
Testo completoAbstract (sommario):
Interactions between cells or between cell and substratum involve specificreceptors and their ligands. Among the various cell surface receptorsidentified during the last decades, the carbohydrate-binding proteins, e.g., lectins are of peculiar interest because glycolipids, glycoproteinsand proteoglycans have been shown to interact with lectins on the surfaceof animal cells. Animal lectins are recognized as molecules playingimportant roles in a variety of biological processes through binding toglycoconjugates and lectin-like receptors such as selectins, sialoadhesins(CD22, CD33), natural killer receptors (NKR-P1, CD69 and CD94/NKG2), hyaluronate receptors (CD44, RHAMM, ICAM-1), B-cell associated antigen(CD23, CD72), γ2 leukocyte integrin (CD11b/CD18) or the well-knownreceptors for mannose, mannose-6-phosphate or asialoglycoprotein havebeen suggested to be able to mediate the transfer of information fromthe outside to the inside of the cell. This review focuses on the mostrecent advances in our understanding of the molecular basis of “outside-in” signaling mediated by lectins. Lectin-likereceptors are involved in signal transduction in a great variety of ways;at the molecular level, they mimic in most of the cases the function ofgrowth factor receptor either coupled to tyrosine kinase activity or toheterotrimeric G protein. They lead to a multiplicity of cellular eventsfollowing their activation depending on factors such as cellular type, species and/or tissue. Nevertheless the potential of surface lectins astransducers is emphasized by the observation that in a few cases lectin-likereceptors induce either novel signal transduction mechanism or newintracellular events with regards to what it has been observed as aconsequence of growth factor receptor activation. This observation bringsthe idea that lectins may offer, as cell surface transducers, an alternativeor additional signaling potential to cell.
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Karpova, I. S. "SPECIFIC INTERACTIONS BETWEEN LECTINS AND RED BLOOD CELLS OF CHORNOBYL CLEANUP WORKERS AS INDICATOR OF SOME LATE RADIATION EFFECTS". Experimental Oncology 38, n. 4 (22 dicembre 2016): 261–66. http://dx.doi.org/10.31768/2312-8852.2016.38(4):261-266.
Testo completoAbstract (sommario):
Aim: Growing interest in lectins is based on their diagnostic and pharmacological potential, especially the ability to inhibit proliferation and initiate apoptosis of cancer cells. In our research microplate lectinoassay able to detect carbohydrate containing structures (receptors) on erythrocyte surface have been proposed for Chornobyl cleanup workers (1986) monitoring. It was expected to reveal specific abnormalities associated with pathological condition arising as a result of late radiation effects. Materials and Methods: Red blood cell (RBC) specimens were taken from 171 persons distributed into the six cohorts: nonexposed donors (1); chronically exposed to the doses below (2) and over 50 cGy (3); exposed to acute radiation without (4) and with manifestation of acute radiation syndrome (5 and 6). Lectins from 24 species of medicinal plants were purified by ethanol fractionation and electrofocusing. Intensity of lectin-receptor interactions was determined in reaction of hemagglutination. Method of flow cytofluorometry was used to study B-cell counts. Hormone levels in blood serum were determined by radioimmunoassay. Results: An elevated ability of RBC to interact with the panel of lectins was found in all cohorts of exposed persons versus nonexposed donors, moreover, changes in the intensity of lectin-receptor binding depended on the dose of irradiation. Diagnostic value of specific RBC reactions with some individual lectins has been elucidated. Elevated intensity of RBC reaction with Zea mays lectin was accompanied by a decrease in serum content of thyroid hormones T4 and T3, as well as reduction of B-cell counts. In the case of Rubus caesius lectin the more intensive reaction with RBC, the higher level of hormone cortisol was observed. Conclusions: Deviations from donor’s norm in intensity of lectin — RBC interactions in radiation exposed men are supposed to carry information about negative changes in their health status following Chornobyl catastrophe and show the diagnostic potential. The most sensitive reactions have been associated primarily with shifts in endocrine and immune systems. This article is a part of a Special Issue entitled “The Chornobyl Nuclear Accident: Thirty Years After”.
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Lakhtin, V. M., M. V. Lakhtin, A. Yu Mironov, V. A. Aleshkin e S. S. Afanasiev. "LECTIN POPULATIONS OF NK CELLS AGAINST VIRUSES-ASSOCIATED TUMORS (REVIEW OF LITERATURE)". Russian Clinical Laboratory Diagnostics 64, n. 5 (7 ottobre 2019): 314–20. http://dx.doi.org/10.18821/0869-2084-2019-64-5-314-320.
Testo completoAbstract (sommario):
Analysis of the human NK (natural killers) cells and their functionally different populations in connection to tumor processes accompanied with viral infections is presented. Receptor lectins (non-immunoglobulin proteins and their complexes recognizing polysaccharides, glycoconjugates and glycopattern-containing molecules) play important role in regulation of innate immunity. Communicative diversity of NK-cell populations (in which lectins cofunction to other receptors) is directed against tumors and viruses. Effectiveness and selectivity of action of NK cell populations can be increased in cooperation together with adaptive immunity. Evaluations of occurrence, redistribution (also under influence of cytokines) and contribution of NK-populations (depending on lectin receptors recognition coupled to multifunctions of receptors) in respect of increasing antitumor and antiviral immune responces are given. The data indicate extended prospects of lectin receptors (coupled to other type receptors) containing NK populations of the network compartment of innate immunity upon realization of different variants of organism protection in cooperation with cellular and humoral immunity. Such NK populations are the basis for further intercellular interactions. Innate immunity Cross-Talk, involving the leader NK cell populations acting according to humoral immunity mechanisms, acts on duty regime (importance for therapy of chronic pathology) that results in providing optimal combined antitumor and antiviral cytokine and cytotoxic responses according to the principle of action as «network-in-network». The influence network of lectin, Ig-like, cytotoxic, other regulator NK populations (also throuph redistribution of production of cytokines by immunocompetent cells) is perspective for forming early prolongated antitumor and antiviral processes of different types in organism. It is of importance to consider CD diversity of receptor repertuar of lectin, Ig-like and other NK populations revealing different ontogenesis as well as to seach patient key NK-populations to select and construct personally (or for contingents in cases of epidemiological significance) optimal therapeutic/prophylactic NK populations (like variants of CAR-T). Aforementioned data indicate perspectiveness of NK cell populations in development of new antitumor/antiviral effective and selective vaccine strategies, preparations and regimes of their applications. Probiotic lectins reveal features of perspective ligands cofunctioning to network of NK cell populations.
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Landi, Alessia, Muriel Mari, Svenja Kleiser, Tobias Wolf, Christine Gretzmeier, Isabel Wilhelm, Dimitra Kiritsi et al. "Pseudomonas aeruginosa lectin LecB impairs keratinocyte fitness by abrogating growth factor signalling". Life Science Alliance 2, n. 6 (15 novembre 2019): e201900422. http://dx.doi.org/10.26508/lsa.201900422.
Testo completoAbstract (sommario):
Lectins are glycan-binding proteins with no catalytic activity and ubiquitously expressed in nature. Numerous bacteria use lectins to efficiently bind to epithelia, thus facilitating tissue colonisation. Wounded skin is one of the preferred niches for Pseudomonas aeruginosa, which has developed diverse strategies to impair tissue repair processes and promote infection. Here, we analyse the effect of the P. aeruginosa fucose-binding lectin LecB on human keratinocytes and demonstrate that it triggers events in the host, upon binding to fucosylated residues on cell membrane receptors, which extend beyond its role as an adhesion molecule. We found that LecB associates with insulin-like growth factor-1 receptor and dampens its signalling, leading to the arrest of cell cycle. In addition, we describe a novel LecB-triggered mechanism to down-regulate host cell receptors by showing that LecB leads to insulin-like growth factor-1 receptor internalisation and subsequent missorting towards intracellular endosomal compartments, without receptor activation. Overall, these data highlight that LecB is a multitask virulence factor that, through subversion of several host pathways, has a profound impact on keratinocyte proliferation and survival.
10
Barre, Annick, Els J. M. Van Damme, Mathias Simplicien, Sophie Le Poder, Bernard Klonjkowski, Hervé Benoist, David Peyrade e Pierre Rougé. "Man-Specific Lectins from Plants, Fungi, Algae and Cyanobacteria, as Potential Blockers for SARS-CoV, MERS-CoV and SARS-CoV-2 (COVID-19) Coronaviruses: Biomedical Perspectives". Cells 10, n. 7 (28 giugno 2021): 1619. http://dx.doi.org/10.3390/cells10071619.
Testo completoAbstract (sommario):
Betacoronaviruses, responsible for the “Severe Acute Respiratory Syndrome” (SARS) and the “Middle East Respiratory Syndrome” (MERS), use the spikes protruding from the virion envelope to attach and subsequently infect the host cells. The coronavirus spike (S) proteins contain receptor binding domains (RBD), allowing the specific recognition of either the dipeptidyl peptidase CD23 (MERS-CoV) or the angiotensin-converting enzyme ACE2 (SARS-Cov, SARS-CoV-2) host cell receptors. The heavily glycosylated S protein includes both complex and high-mannose type N-glycans that are well exposed at the surface of the spikes. A detailed analysis of the carbohydrate-binding specificity of mannose-binding lectins from plants, algae, fungi, and bacteria, revealed that, depending on their origin, they preferentially recognize either complex type N-glycans, or high-mannose type N-glycans. Since both complex and high-mannose glycans substantially decorate the S proteins, mannose-specific lectins are potentially useful glycan probes for targeting the SARS-CoV, MERS-CoV, and SARS-CoV-2 virions. Mannose-binding legume lectins, like pea lectin, and monocot mannose-binding lectins, like snowdrop lectin or the algal lectin griffithsin, which specifically recognize complex N-glycans and high-mannose glycans, respectively, are particularly adapted for targeting coronaviruses. The biomedical prospects of targeting coronaviruses with mannose-specific lectins are wide-ranging including detection, immobilization, prevention, and control of coronavirus infection.
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Salmon, J. E., S. Kapur e R. P. Kimberly. "Opsonin-independent ligation of Fc gamma receptors. The 3G8-bearing receptors on neutrophils mediate the phagocytosis of concanavalin A-treated erythrocytes and nonopsonized Escherichia coli." Journal of Experimental Medicine 166, n. 6 (1 dicembre 1987): 1798–813. http://dx.doi.org/10.1084/jem.166.6.1798.
Testo completoAbstract (sommario):
We report that phagocytosis by human neutrophils of Con A-treated erythrocytes (E-Con A) and nonopsonized Escherichia coli with mannose-binding adhesions is mediated by the Fc gamma receptor bearing the 3G8 epitope. Modulation of Fc receptors by pretreating with aggregated-IgG or with 3G8 anti-Fc gamma receptor mAb markedly inhibited internalization of E-Con A and E. coli without altering their cell surface attachment. Phagocytosis of these probes was specifically blocked by alpha-methylmannoside and D-mannose and not by other monosaccharides. Thus, recognition of E-Con A and E. coli by the Fc receptor is dependent upon the mannose-specific interaction with lectin or lectin-like adhesions. These data demonstrate that ligands other than the classical IgG opsonins can bind to classical immune receptors for IgG through lectin-carbohydrate interactions.
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Abbott, W. M., E. F. Hounsell e T. Feizi. "Further studies of oligosaccharide recognition by the soluble 13 kDa lectin of bovine heart muscle. Ability to accommodate the blood-group-H and -B-related sequences". Biochemical Journal 252, n. 1 (15 maggio 1988): 283–87. http://dx.doi.org/10.1042/bj2520283.
Testo completoAbstract (sommario):
Oligosaccharide recognition by the 13 kDa soluble lectin from bovine heart muscle has been investigated by inhibition of binding of the 125I-labelled lectin to trypsin-treated rabbit erythrocytes. The results indicate that the Type 1 (Gal beta 1-3GlcNAc) and the Type 2 (Gal beta 1-4GlcNAc) backbone structures are the basic recognition units, and that the blood-group-H structure, the blood-group-B structure, the ‘B-like’ structure [afucosyl-(blood group B)] and the alpha 2-3 sialylated analogues of the backbone structures can also be accommodated and hence are candidate receptor structures for the lectin. A comparison of available inhibition data on six other soluble beta-galactoside-binding lectins (three from human lung and three from rat lung) has shown some common features among these and the bovine lectin, e.g. in general a stronger reaction with N-acetyl-lactosamine than with lactose, and a lack of reaction with 3-fucosyl-lactose and 6-sialyl-lactose. However, there are distinctive features among the lectins, e.g. differences in relative reactions with the blood-group-A structure, and no two of the lectins appear to be identical in their fine specificities.
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Bardosi, A., T. Dimitri, B. Wosgien e H. J. Gabius. "Expression of endogenous receptors for neoglycoproteins, especially lectins, that allow fiber typing on formaldehyde-fixed, paraffin-embedded muscle biopsy specimens. A glycohistochemical, immunohistochemical, and glycobiochemical study." Journal of Histochemistry & Cytochemistry 37, n. 7 (luglio 1989): 989–98. http://dx.doi.org/10.1177/37.7.2732460.
Testo completoAbstract (sommario):
A panel of biotinylated (neo)glycoproteins was used for specific detection of endogenous sugar receptors, especially lectins, in formaldehyde-fixed, paraffin-embedded muscle biopsy specimens from human deltoid, quadriceps, and biceps muscles, tibial and quadriceps muscles of rat, and bovine masseter muscle. The glycohistochemical probes used consisted of conjugates of a labeled, histochemically inert carrier protein and various covalently linked, histochemically crucial sugar moieties. Specific binding of alpha-L-fucoside, beta-D-galactoside, beta-D-xyloside, and alpha-D-mannoside to muscle sections was detected, showing no species-specific differences. The presence of receptors for the N-acetylated sugars in natural glycoconjugates, and for sugars with a phosphate group, i.e., mannose-6-phosphate and galactose-6-phosphate, was demonstrated glycohistochemically. However, these binding specificities revealed species-specific differences, e.g., the absence of N-acetyl-D-galactosamine-specific receptors or galactose-6-phosphate-specific receptors in rat muscle. Other charged sugars included glucuronic acid and sialic acid, which bound only to ox and rat muscle or failed to reveal their respective receptors in all types of muscle investigated. This different extent of staining with anionic probes served as a further control to ascertain carbohydrate binding specificity. Positive glycohistochemical reaction developed within sarcomeres only at the level of A-bands. Granular staining was observed in the sarcoplasm among the myofibrils and also in the subsarcolemmal regions. Differences in expression of glycohistochemically detectable sugar receptors were noted between type 1, type 2A, and type 2B fibers. The molecular properties of one type of glycohistochemically detectable sugar receptor were inferred both immunohistochemically and biochemically. An antiserum against an endogenous beta-galactoside-specific lectin from muscle tissue localized this lectin within sections consistently similar to (neo)glycoproteins, detecting beta-galactoside-specific receptor(s). This similarity of binding patterns strongly supports the assumption that (neo)glycoproteins with beta-galactoside termini indeed bind to the respective endogenous lectin. The lectin-specific antiserum enabled us to ascertain that glycohistochemical fiber typing corresponds to enzyme histochemical typing. Moreover, biochemical purification using affinity chromatography and subsequent affinity elution revealed only the immunohistochemically detectable beta-galactoside-specific lectin. Consequently, use of a panel of neoglycoproteins, when frozen sections for histochemical analysis are not available, co
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Rushton, Emma, Danielle L. Kopke e Kendal Broadie. "Extracellular heparan sulfate proteoglycans and glycan-binding lectins orchestrate trans-synaptic signaling". Journal of Cell Science 133, n. 15 (1 agosto 2020): jcs244186. http://dx.doi.org/10.1242/jcs.244186.
Testo completoAbstract (sommario):
ABSTRACTThe exceedingly narrow synaptic cleft (<20 nm) and adjacent perisynaptic extracellular space contain an astonishing array of secreted and membrane-anchored glycoproteins. A number of these extracellular molecules regulate intercellular trans-synaptic signaling by binding to ligands, acting as co-receptors or modulating ligand–receptor interactions. Recent work has greatly expanded our understanding of extracellular proteoglycan and glycan-binding lectin families as key regulators of intercellular signaling at the synapse. These secreted proteins act to regulate the compartmentalization of glycoprotein ligands and receptors, crosslink dynamic extracellular and cell surface lattices, modulate both exocytosis and endocytosis vesicle cycling, and control postsynaptic receptor trafficking. Here, we focus closely on the Drosophila glutamatergic neuromuscular junction (NMJ) as a model synapse for understanding extracellular roles of the many heparan sulfate proteoglycan (HSPG) and lectin proteins that help determine synaptic architecture and neurotransmission strength. We particularly concentrate on the roles of extracellular HSPGs and lectins in controlling trans-synaptic signaling, especially that mediated by the Wnt and BMP pathways. These signaling mechanisms are causally linked to a wide spectrum of neurological disease states that impair coordinated movement and cognitive functions.
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Eble, Johannes. "Structurally Robust and Functionally Highly Versatile—C-Type Lectin (-Related) Proteins in Snake Venoms". Toxins 11, n. 3 (1 marzo 2019): 136. http://dx.doi.org/10.3390/toxins11030136.
Testo completoAbstract (sommario):
Snake venoms contain an astounding variety of different proteins. Among them are numerous C-type lectin family members, which are grouped into classical Ca2+- and sugar-binding lectins and the non-sugar-binding snake venom C-type lectin-related proteins (SV-CLRPs), also called snaclecs. Both groups share the robust C-type lectin domain (CTLD) fold but differ in a long loop, which either contributes to a sugar-binding site or is expanded into a loop-swapping heterodimerization domain between two CLRP subunits. Most C-type lectin (-related) proteins assemble in ordered supramolecular complexes with a high versatility of subunit numbers and geometric arrays. Similarly versatile is their ability to inhibit or block their target molecules as well as to agonistically stimulate or antagonistically blunt a cellular reaction triggered by their target receptor. By utilizing distinct interaction sites differentially, SV-CLRPs target a plethora of molecules, such as distinct coagulation factors and receptors of platelets and endothelial cells that are involved in hemostasis, thrombus formation, inflammation and hematogenous metastasis. Because of their robust structure and their high affinity towards their clinically relevant targets, SV-CLRPs are and will potentially be valuable prototypes to develop new diagnostic and therapeutic tools in medicine, provided that the molecular mechanisms underlying their versatility are disclosed.
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Hoober, J. Kenneth. "ASGR1 and Its Enigmatic Relative, CLEC10A". International Journal of Molecular Sciences 21, n. 14 (8 luglio 2020): 4818. http://dx.doi.org/10.3390/ijms21144818.
Testo completoAbstract (sommario):
The large family of C-type lectin (CLEC) receptors comprises carbohydrate-binding proteins that require Ca2+ to bind a ligand. The prototypic receptor is the asialoglycoprotein receptor-1 (ASGR1, CLEC4H1) that is expressed primarily by hepatocytes. The early work on ASGR1, which is highly specific for N-acetylgalactosamine (GalNAc), established the foundation for understanding the overall function of CLEC receptors. Cells of the immune system generally express more than one CLEC receptor that serve diverse functions such as pathogen-recognition, initiation of cellular signaling, cellular adhesion, glycoprotein turnover, inflammation and immune responses. The receptor CLEC10A (C-type lectin domain family 10 member A, CD301; also called the macrophage galactose-type lectin, MGL) contains a carbohydrate-recognition domain (CRD) that is homologous to the CRD of ASGR1, and thus, is also specific for GalNAc. CLEC10A is most highly expressed on immature DCs, monocyte-derived DCs, and alternatively activated macrophages (subtype M2a) as well as oocytes and progenitor cells at several stages of embryonic development. This receptor is involved in initiation of TH1, TH2, and TH17 immune responses and induction of tolerance in naïve T cells. Ligand-mediated endocytosis of CLEC receptors initiates a Ca2+ signal that interestingly has different outcomes depending on ligand properties, concentration, and frequency of administration. This review summarizes studies that have been carried out on these receptors.
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Hart, Derek N. J., Seema Khan, Elisabetta d’Aniello, Kylie J. McDonald e Masato Kato. "Role of Novel C-Type Lectin Receptor DCL-1 in Phagocytes and Dendritic Cells." Blood 110, n. 11 (16 novembre 2007): 2419. http://dx.doi.org/10.1182/blood.v110.11.2419.2419.
Testo completoAbstract (sommario):
Abstract Cell surface C-type lectins are implicated in many aspects of immunity. For example, professional phagocytes utilise cell surface C-type lectins in pathogen recognition/binding and phagocytosing the pathogens for destruction and/or antigen processing (e.g. mannose receptor, DC-SIGN, dectin-1). Some C-type lectins are involved in cell-cell adhesion and trafficking of leukocytes (e.g. selectins). DCL-1 is a small type I transmembrane C-type lectin receptor, discovered as a genetic fusion partner of DEC-205. DCL-1 protein was highly conserved amongst the human, mouse and rat orthologs. The human DCL-1 gene, composed of 6 exons, was located to a cluster of type I transmembrane C-type lectin genes on chromosomal band 2q24. Multiple expression array, RT-PCR and FACS analysis using new anti-hDCL-1 mAbs established that DCL-1 expression in leukocytes was restricted to monocytes, macrophages, granulocytes and DC, although DCL-1 mRNA was present in many tissues. Stable hDCL-1 CHO cell transfectants endocytosed FITC-conjugated anti-hDCL-1 mAb rapidly (t1/2 = 20 min) and phagocytosed anti-hDCL-1 mAb-coated microbeads, indicating that DCL-1 may act as an antigen uptake receptor. However, anti-DCL-1 mAb-coated microbead binding and subsequent phagocytic uptake by macrophages was ∼8-fold less efficient than that of anti-macrophage mannose receptor (MMR/CD206) or anti-DEC-205/CD205 mAb-coated microbeads. Confocal studies showed that DCL-1 colocalized with F-actin in filopodia, lamellipodia and podosomes in macrophages and the colocalization was not affected with cytochalasin D, whereas the MMR/CD206 and DEC-205/CD205 did not colocalize with F-actin. Furthermore, DCL-1-EGFP transiently expressed in COS-1 cells colocalized with F-actin at cellular cortex and microvilli. These data suggest that hDCL-1 is an unconventional lectin receptor that plays roles not only in endocytosis/phagocytosis, but also in myeloid cell adhesion and migration.
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van Kooyk, Yvette. "C-type lectins on dendritic cells: key modulators for the induction of immune responses". Biochemical Society Transactions 36, n. 6 (19 novembre 2008): 1478–81. http://dx.doi.org/10.1042/bst0361478.
Testo completoAbstract (sommario):
DCs (dendritic cells) are specialized in the recognition of pathogens and play a pivotal role in the control of immune responses. DCs are also important for homoeostatic control, recognizing self-antigens and tolerizing the tissue environment. The nature of the antigen recognized tilts the balance towards immunity or tolerance. CLRs (C-type lectin receptors) expressed by DC are involved in the recognition and capture of many glycosylated self-antigens and pathogens. It is now becoming clear that these CLRs may not only serve as antigen receptors allowing internalization and antigen presentation, but also function in the recognition of glycosylated self-antigens, and as adhesion and/or signalling molecules. The expression of C-type lectins is very sensitive to maturation stimuli, leading to down-regulation as DCs mature. CLRs such as DC-SIGN (DC-specific intracellular adhesion molecule-3 grabbing non-integrin) recognizes high-mannose-containing structures and Lewis antigens (Lex, Ley, Leb and Lea), whereas the CLR MGL (macrophage galactose/N-acetylgalactosamine-specific C-type lectin) recognizes GalNAc. Lex, Ley and GalNAc glycan structures are often expressed on tumours. We have demonstrated that glycan modification of antigen can strongly enhance MHC class I responses and the induction of antigen-specific cytotoxic T-lymphocytes, indicating that glycosylated antigen targets C-type lectin to enhance antigen-specific T-cell responses. Moreover, these CLRs induce signalling processes in DCs and specific cytokine responses in combination with TLR (Toll-like receptor) triggering. This implies that specific C-type lectin-targeted antigens can regulate T-cell polarization. Understanding the diversity of C-type lectins being expressed on DCs as well as their carbohydrate-specific recognition profiles should promote understanding of pathogen recognition in many diseases, as well as the regulation of cellular interactions of DCs that are essential in the control of immunity.
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Aucoin, Emilyn B., Elizabeth Skapinker, Abdulrahman M. Yaish, Yunfan Li, Haley L. Kombargi, Daniel Jeyaraj, Pankaj Garg, Nicole Mendonza, Cecile Malardier-Jugroot e Myron R. Szewczuk. "Glycosyl Mobile Radical Structures of Folic Acid Receptors Impact the Internalization of Functionalized Folate Amphiphilic Alternating Copolymer in Cancer Cells". Receptors 3, n. 4 (21 ottobre 2024): 457–73. http://dx.doi.org/10.3390/receptors3040023.
Testo completoAbstract (sommario):
Folate receptor alpha (FRα) is a glycosylphosphatidylinositol (GPI) membrane-anchored protein containing three N-glycosylated residues at the N47, N139, and N179 termini. These glycosylation sites have been reported to be crucial for the receptor’s structural integrity and its ability to bind and internalize FA. Here, we investigated the role of FRα glycosylation in the binding and internalization efficacy of FA–DABA–SMA in pancreatic PANC-1 cancer cells. There is a strong association of the FA copolymer with FRα with a Pearson coefficient R-value of 0.7179. PANC-1 cancer cells were pretreated with maackia amurensis lectin II (MAL-2), sambucus Nigra lectin (SNA-1), peanut agglutinin (PNA), and wheat germ agglutinin lectin (WGA) at different doses followed by 20 kDa and 350 kDa FA–DABA–SMA loaded with coumarin 153 (C153). Increasing the dosage of MAL2, SNA-1, PNA, and WGA concomitantly and significantly increased the internalization of C153-loaded FA–DABA–SMA in the cells. The half maximal effective lectin concentrations (EC50) to induce cellular internalization into the cytoplasm of the lectins for MAL-2 were 35.88 µg/mL, 3.051 µg/mL for SNA-1, 7.883 µg/mL for PNA, and 0.898 µg/mL for WGA. Live cell imaging of the internalization of 20 kDa and 350 kDa FA copolymers indicated an aggregation of 350 kDa copolymer with FRα in the cytoplasm. In contrast, the 20 kDa FA copolymer remained in the membrane. The data indicate for the first time that the mobile positions of the glycosyl radical groups and the receptor tilt in generating steric hindrance impacted the individual FRα receptors in the binding and internalization of 350 kDa FA–DABA–SMA in cancer cells.
20
Rohlenová, Anna, Miroslav Ledvina, David Šaman e Karel Bezouška. "Synthesis of Linear and Branched Regioisomeric Chitooligosaccharides as Potential Mimetics of Natural Oligosaccharide Ligands of Natural Killer Cells NKR-P1 and CD69 Lectin Receptors". Collection of Czechoslovak Chemical Communications 69, n. 9 (2004): 1781–804. http://dx.doi.org/10.1135/cccc20041781.
Testo completoAbstract (sommario):
Regioisomer of chitobiose 13 with β(1→3) glycosidic bond and branched analog of chitotriose 25 having β(1→4) and β(1→3) glycosidic bonds, were prepared and tested as potential mimetics of natural oligosaccharide ligands for activating lectin receptors NKR-P1A and CD69 of natural killer (NK) cells. The structural requirements of NKR-P1 lectin receptor on effective mimetics of its natural ligands has been discussed. A significant binding activity of the branched trisaccharide 25 to the receptor CD69 was observed.
21
Lakhtin, M. V., V. M. Lakhtin, V. A. Aleshkin, M. S. Afanasiev e S. S. Afanasiev. "LECTINS IN ANTI-CANCER STRATEGIES". Acta Biomedica Scientifica 3, n. 4 (28 luglio 2018): 69–77. http://dx.doi.org/10.29413/abs.2018-3.4.11.
Testo completoAbstract (sommario):
The published during last few years data concerning communicative role of lectins (proteins and their complexes which recognize carbohydrates, glycoconjugates and their patterns) in on-duty supporting and increasing anticancer status of human immunity are analyzed. Examples of lectin-(glycoconjugate pattern) strategies, approaches and tactic variants in study and development of anticancer treatments, principle variants of therapy, possible vaccines in 35 cases of blood connected tumors (leukemia, lymphomas, others), solid tumors (carcinomas, sarcoma, cancers of vaginal biotopes, prostate, bladder, colon, other intestinal compartments, pancreas, liver, kidneys, others) and cancer cell lines are described and systemized. The list of mostly used communicative lectins (pattern recognition receptors, their soluble forms, other soluble lectins possessing specificities of importance) involving in key intercellular cascades and pathway co-functioning is presented. The regulation of resulting expression of distinct active lectins (available and hetero/di/oligomeric forms) and their interaction to adequate glycoconjugate patterns as well as influence distribution of co-functioning lectins and antigens CD between populations and subpopulations of antigen-presented cells (dendritic cells cDC, mDC, moDC, pDC; macrophages M2 and M1), mucosal M-cells, NK-cells play key role for choice and development of anticancer complex procedures increasing innate and innate-coupled immune responses. Prospects of (receptor lectin)-dependent intercellular communications and targeting glycoconjugate constructions into innate immunity cells for therapy of cancer and development of anticancer vaccines are evaluated and discussed.
22
Gabius, H. J., B. Kohnke-Godt, M. Leichsenring e A. Bardosi. "Heparin binding lectin of human placenta as a tool for histochemical ligand localization and isolation." Journal of Histochemistry & Cytochemistry 39, n. 9 (settembre 1991): 1249–56. http://dx.doi.org/10.1177/39.9.1918943.
Testo completoAbstract (sommario):
Biotinylated heparin has been used to detect the presence of specific binding sites in sections of human placenta, which has prompted demonstration of expression of lectin activity for this proteoglycan. Purification of this lectin from full-term placenta facilitates the synthesis of its biotinylated derivative, using biotin-amidocaproyl hydrazide, without affecting its activity. It also enables immunization to obtain antibodies. The labeled lectin is shown to bind specifically to nuclear and cytoplasmic locations in various cell types of human placenta, nuclear expression of lectin binding sites being more pronounced at the full-term stage than after 8 weeks of development. The structurally related histone H2B exhibits obvious differences in its binding pattern. The presence of ligands accessible to the lectin whose binding activity can be inhibited by addition of an excess of heparin correlates in most instances with the level of lectin expression detected immunohistochemically. Biochemical information on the nature of the glycohistochemically inferred lectin-specific ligand(s) is obtained by affinity chromatography on resin-immobilized lectin. It leads to isolation of a proteoglycan with similar electrophoretic mobility in agarose-polyacrylamide gel electrophoresis relative to the independently purified heparan sulfate-containing fibronectin binding proteoglycan from human placenta. Both fractions inhibit binding of heparin to the lectin and contain immunologically detected co-purified lectin, emphasizing their ligand properties. Application of labeled tissue lectins in conjunction with lectin-specific antibodies is proposed to obtain valuable insights into the expression of the receptor as well as the ligand part of protein-carbohydrate recognition.
23
Aglyamova, Aliya, Natalia Petrova, Oleg Gorshkov, Liudmila Kozlova e Tatyana Gorshkova. "Growing Maize Root: Lectins Involved in Consecutive Stages of Cell Development". Plants 11, n. 14 (7 luglio 2022): 1799. http://dx.doi.org/10.3390/plants11141799.
Testo completoAbstract (sommario):
Proteins that carry specific carbohydrate-binding lectin domains have a great variety and are ubiquitous across the plant kingdom. In turn, the plant cell wall has a complex carbohydrate composition, which is subjected to constant changes in the course of plant development. In this regard, proteins with lectin domains are of great interest in the context of studying their contribution to the tuning and monitoring of the cell wall during its modifications in the course of plant organ development. We performed a genome-wide screening of lectin motifs in the Zea mays genome and analyzed the transcriptomic data from five zones of primary maize root with cells at different development stages. This allowed us to obtain 306 gene sequences encoding putative lectins and to relate their expressions to the stages of root cell development and peculiarities of cell wall metabolism. Among the lectins whose expression was high and differentially regulated in growing maize root were the members of the EUL, dirigent–jacalin, malectin, malectin-like, GNA and Nictaba families, many of which are predicted as cell wall proteins or lectin receptor-like kinases that have direct access to the cell wall. Thus, a set of molecular players was identified with high potential to play important roles in the early stages of root morphogenesis.
24
Barre, Annick, Christine Hervé, Bernard Lescure e Pierre Rougé. "Lectin Receptor Kinases in Plants". Critical Reviews in Plant Sciences 21, n. 4 (luglio 2002): 379–99. http://dx.doi.org/10.1080/0735-260291044287.
Testo completo
25
Hlaing, May Thinzar, Yoshiya Horimoto, Kaori Denda-Nagai, Haruhiko Fujihira, Miki Noji, Hiroyuki Kaji, Azusa Tomioka et al. "Tamoxifen-resistant breast cancer cells exhibit reactivity with Wisteria floribunda agglutinin". PLOS ONE 17, n. 8 (25 agosto 2022): e0273513. http://dx.doi.org/10.1371/journal.pone.0273513.
Testo completoAbstract (sommario):
Glycosylation is one of the most important post-translational modifications of cell surface proteins involved in the proliferation, metastasis and treatment resistance of cancer cells. However, little is known about the role of glycosylation as the mechanism of breast cancer cell resistance to endocrine therapy. Herein, we aimed to identify the glycan profiles of tamoxifen-resistant human breast cancer cells, and their potential as predictive biomarkers for endocrine therapy. We established tamoxifen-resistant cells from estrogen receptor-positive human breast cancer cell lines, and their membrane-associated proteins were subjected to lectin microarray analysis. To confirm differential lectin binding to cellular glycoproteins, we performed lectin blotting analyses after electrophoretic separation of the glycoproteins. Mass spectrometry of the tryptic peptides of the lectin-bound glycoproteins was further conducted to identify glycoproteins binding to the above lectins. Finally, expression of the glycans that were recognized by a lectin was investigated using clinical samples from patients who received tamoxifen treatment after curative surgery. Lectin microarray analysis revealed that the membrane fractions of tamoxifen-resistant breast cancer cells showed increased binding to Wisteria floribunda agglutinin (WFA) compared to tamoxifen-sensitive cells. Glycoproteins seemed to be responsible for the differential WFA binding and the results of mass spectrometry revealed several membrane glycoproteins, such as CD166 and integrin beta-1, as candidates contributing to increased WFA binding. In clinical samples, strong WFA staining was more frequently observed in patients who had developed distant metastasis during tamoxifen treatment compared with non-relapsed patients. Therefore, glycans recognized by WFA are potentially useful as predictive markers to identify the tamoxifen-resistant and relapse-prone subset of estrogen receptor-positive breast cancer patients.
26
Takebayashi, Kohzo, Tatsuhiko Suzuki, Mototaka Yamauchi, Kenji Hara, Takafumi Tsuchiya, Toshihiko Inukai e Koshi Hashimoto. "Association of circulating soluble lectin-like oxidized low-density lipoprotein receptor-1 with inflammatory markers and urinary albumin excretion in patients with type 2 diabetes". SAGE Open Medicine 9 (gennaio 2021): 205031212110644. http://dx.doi.org/10.1177/20503121211064468.
Testo completoAbstract (sommario):
Objectives: The main purpose of the study was to study the association between circulating soluble lectin-like oxidized low-density lipoprotein receptor-1 levels and various markers, including inflammatory markers such as high-sensitivity C-reactive protein and fibrinogen, serum lipids, and renal function, in patients with poorly controlled type 2 diabetes. Methods: The subjects were 70 patients (men 45, women 25) who were hospitalized for treatment of poor glycemic control. Plasma soluble lectin-like oxidized low-density lipoprotein receptor-1 levels were assayed using a sandwich chemiluminescence enzyme immunoassay. Results: Circulating soluble lectin-like oxidized low-density lipoprotein receptor-1 was significantly positively correlated with lectin-like oxidized low-density lipoprotein-1 ligands containing apolipoprotein B, reflecting modified low-density lipoprotein, and with inflammatory markers such as high-sensitivity C-reactive protein and fibrinogen. In addition, there was a significant positive correlation between soluble lectin-like oxidized low-density lipoprotein receptor-1 and urinary albumin excretion. Conclusions: Soluble lectin-like oxidized low-density lipoprotein receptor-1 may serve as a marker reflecting the degrees of inflammation and albuminuria in patients with poorly controlled type 2 diabetes.
27
Thorkelsson, T., G. M. Ciraolo, G. F. Ross, J. A. Whitsett e R. E. Morris. "Lectin activity of the major surfactant protein (SP-A) may participate in, but is not required for, binding to rat type II cells." Journal of Histochemistry & Cytochemistry 40, n. 5 (maggio 1992): 643–49. http://dx.doi.org/10.1177/40.5.1573247.
Testo completoAbstract (sommario):
Pulmonary surfactant is a complex mixture of lipids and proteins, of which surfactant protein A (SP-A) is the most abundant glycoprotein. The SP-A molecule has several distinct structural features that include a lectin-like domain, sharing structural features with other mammalian lectins. We have tested the hypothesis that lectin activity of the SP-A molecule is required for the binding to its receptor on the surface of alveolar Type II cells. By using colloidal gold immunocytochemistry in conjunction with electron microscopy, we evaluated the ability of mannosylated proteins to inhibit canine SP-A binding to rat Type II cells in vitro. After preincubation of SP-A with the mannosylated protein horse-radish peroxidase (HRP), SP-A was incubated with isolated filter-grown Type II cells. HRP did not alter the binding of SP-A to the Type II cell surface. Evidence that SP-A did bind to HRP was shown by coincident observation of gold-labeled SP-A and HRP precipitates. These results provide visual evidence that the lectin activity associated with SP-A is not required for its binding to receptor on rat alveolar Type II epithelial cells.
28
Valle Argos, Beatriz, Giorgia Chiodin, Francesco Forconi, Richard Burack, Philip Rock, Graham Packham e Freda K. Stevenson. "Lymphoma-Specific Subversion of B-Cell Receptor Signaling By Macrophage Lectins". Blood 132, Supplement 1 (29 novembre 2018): 2865. http://dx.doi.org/10.1182/blood-2018-99-110954.
Testo completoAbstract (sommario):
Abstract The clue that surface Ig (sIg) is implicated in the pathogenesis of follicular lymphoma (FL) is that in FL the vast majority of the sIg variable regions are structurally modified by insertion of mannose residues into the antigen-binding sites. This is tumor-specific and reflects positive selection of sequence motifs for glycan addition introduced during somatic hypermutation. The termination at high mannoses is very unusual in cell surface molecules and it confers an ability to interact with local lectins expressed by macrophages. In this respect, the mannose cloaking of the sIg receptor resembles that of human immunodeficiency virus (HIV), which acquires a similar mannose coat to facilitate binding to macrophages. The lectin DC-SIGN is upregulated in FL, likely via local IL-4, and is the strong lectin candidate. To address the question of the functional implications of interaction between DC-SIGN and sIgM we used a FL-derived cell line (WSU-FSCCL) which expresses sIg-mannoses. We found that two recombinant derivatives of DC-SIGN (DC-SIGN-Fc or DC-SIGN-HA) bind to the sIgM but not to a cell line which express sIgM without mannose insertion. Although the mannoses are an integral part of the sIgM, and anti-IgM induces a Ca2+ flux, DC-SIGN binds but does not mimic anti-IgM. In the WSU-FSCCL cell line it remains on the surface IgM without inducing a Ca2+ response and without mediating endocytosis of the sIgM. However, DC-SIGN does act on the sIgM as revealed by the effects of pre-exposure of the cells to either DC-SIGN derivative, which, although there is no blocking of access of anti-IgM, alters the ability of the cell to respond to stimulation. Pre-exposure appears to partially paralyze the subsequent sIgM-induced Ca2+ flux indicating a lectin-mediated modification of sIgM function. On engagement by anti-IgM, sIg undergoes conventional endocytosis and this was confirmed in WSU-FSCCL. Inhibitors which block signaling did not affect endocytosis, indicating bifurcation of signaling and endocytic pathways. Knowing that DC-SIGN derivatives, again in contrast to anti-IgM, did not induce endocytosis of sIgM, we then asked if the paralysis of the sIgM-mediated Ca2+ flux by pre-exposure to lectin affected anti-IgM-induced endocytosis, and found that it did not. This confirms the separation of signaling and endocytosis and indicates that whatever change is occurring in sIgM due to lectin exposure does not remove the sIgM from the endocytic machinery. We then investigated primary FL cases, using a splenic FL and 2 lymph node FLs, all carrying N-glycosylation motifs and able to bind DC-SIGN. We focused on the DC-SIGN-HA derivative, which gives no detectable Ca2+ flux signal by itself. Binding of the lectin again paralyzed subsequent anti-IgM-induced Ca2+ flux in all cases (Fig.1A), confirming the results with the cell line. Further investigation revealed that the lectin prevents early events after antigen binding to the sIg receptor reducing SYK phosphorylation and leading to a reduced Ca2+ mobilization (Fig.1B). In conclusion, modulation of the B-cell receptor by mannose addition to the antigen-binding site allows lectin access from innate microenvironmental cells. The effect of this is to provide a low level/null signal without loss by endocytosis. The novel finding is that this interaction then lowers the function of the B-cell receptor and perhaps blocks potential interference by antigen. There may be a parallelism with reports of modification of T-cell receptor function by galectins, with both pointing to the role of post-translational modification adding another layer of control on the operation of the major immune receptors. In the case of FL, this has been exploited to maintain tumor cells in the hostile environment of the germinal center. The apparently lymphoma-specific adaptation offers opportunities for targeted inhibition of the interaction. Figure 1. Figure 1. Disclosures Forconi: Janssen-Cilag: Consultancy; Abbvie: Consultancy. Packham:Aquinox: Research Funding.
29
ZANETTA, Jean-Pierre, Catherine ALONSO e Jean-Claude MICHALSKI. "Interleukin 2 is a lectin that associates its receptor with the T-cell receptor complex". Biochemical Journal 318, n. 1 (15 agosto 1996): 49–53. http://dx.doi.org/10.1042/bj3180049.
Testo completoAbstract (sommario):
To determine the nature of the mechanism by which the binding of interleukin-2 (IL-2) to its receptor (IL-2Rβ) induces IL-2Rβ phosphorylation by the tyrosine kinase p56lck associated with the T-cell receptor (TCR) complex, we investigated the possibility that this mechanism was due to the putative lectin activity of IL-2 ([Sherblom, Sathyamoorthy, Decker and Muchmore (1989) J. Immunol. 143, 939–944]. Here we demonstrate that IL-2 is a calcium-independent lectin specific for oligomannosidic N-glycans with five and six mannose residues. This lectin activity is preserved after binding of IL-2 to IL-2Rβ. IL-2 behaves as a bifunctional molecule that associates IL-2Rβ with specific glycoprotein ligands of the TCR complex including a glycosylated form of CD3.
30
Alsolami, Ahmed, Amina I. Dirar, Emadeldin Hassan E. Konozy, Makarim El-Fadil M. Osman, Mohanad A. Ibrahim, Khalid Farhan Alshammari, Fawwaz Alshammari, Meshari Alazmi e Kamaleldin B. Said. "Genome-Wide Mining of Selaginella moellendorffii for Hevein-like Lectins and Their Potential Molecular Mimicry with SARS-CoV-2 Spike Glycoprotein". Current Issues in Molecular Biology 45, n. 7 (14 luglio 2023): 5879–901. http://dx.doi.org/10.3390/cimb45070372.
Testo completoAbstract (sommario):
Multidisciplinary research efforts on potential COVID-19 vaccine and therapeutic candidates have increased since the pandemic outbreak of SARS-CoV-2 in 2019. This search has become imperative due to the increasing emergences and limited widely available medicines. The presence of bioactive anti-SARS-CoV-2 molecules was examined from various plant sources. Among them is a group of proteins called lectins that can bind carbohydrate moieties. In this article, we present ten novel, chitin-specific Hevein-like lectins that were derived from Selaginella moellendorffii v1.0’s genome. The capacity of these lectin homologs to bind with the spike protein of SARS-CoV-2 was examined. Using the HDOCK server, 3D-modeled Hevein-domains were docked to the spike protein’s receptor binding domain (RBD). The Smo446851, Smo125663, and Smo99732 interacted with Asn343-located complex N-glycan and RBD residues, respectively, with binding free energies of −17.5, −13.0, and −26.5 Kcal/mol. The molecular dynamics simulation using Desmond and the normal-state analyses via torsional coordinate association for the Smo99732-RBD complex using iMODS is characterized by overall higher stability and minimum deformity than the other lectin complexes. The three lectins interacting with carbohydrates were docked against five individual mutations that frequently occur in major SARS-CoV-2 variants. These were in the spike protein’s receptor-binding motif (RBM), while Smo125663 and Smo99732 only interacted with the spike glycoprotein in a protein–protein manner. The precursors for the Hevein-like homologs underwent additional characterization, and their expressional profile in different tissues was studied. These in silico findings offered potential lectin candidates targeting key N-glycan sites crucial to the virus’s virulence and infection.
31
Sawyer, J. T., e R. A. Akeson. "Differential redistribution of lectin receptor classes on clonal rat myotubes and myoblasts". Journal of Cell Science 83, n. 1 (1 luglio 1986): 181–96. http://dx.doi.org/10.1242/jcs.83.1.181.
Testo completoAbstract (sommario):
To evaluate the relative mobilities of cell surface glycoconjugates during myogenesis we have studied the redistribution of fluorescein-conjugated plant lectins on L6 rat myogenic cells. Previous experiments had demonstrated that the receptors for the lectins soybean agglutinin (SBA), wheat germ agglutinin, concanavalin A and Lens culinaris agglutinin all were relatively uniformly distributed on both myoblasts and myotubes, and that SBA receptors were capable of rapid redistribution on myotubes but not myoblasts at 4 degrees C (Sawyer & Akeson, 1983). Here we show that when SBA-labelled myoblasts are incubated at 37 degrees C, or for extended times at 4 degrees C, the lectin aggregates as on myotubes. So it appears that SBA-binding components show a quantitative rather than qualitative change in their mobility during L6 differentiation. In addition, the redistribution of the three other lectins on myoblasts and myotubes was either less prominent (i.e. showing fewer apparent surface clusters) or occurred less rapidly than with SBA. None of these three lectins showed striking differences in mobility between myoblasts and myotubes. Thus, it appears that SBA binds to a subset of surface glycoconjugates that is relatively highly mobile, and that this mobility is specifically enhanced with differentiation.
32
Itin, C., A. C. Roche, M. Monsigny e H. P. Hauri. "ERGIC-53 is a functional mannose-selective and calcium-dependent human homologue of leguminous lectins." Molecular Biology of the Cell 7, n. 3 (marzo 1996): 483–93. http://dx.doi.org/10.1091/mbc.7.3.483.
Testo completoAbstract (sommario):
Based on sequence homologies with leguminous lectins, the intermediate compartment marker ERGIC-53 was proposed to be a member of a putative new class of animal lectins associated with the secretory pathway. Independent, a promyelocytic protein, MR60, was purified by mannose-column chromatography, and a cDNA was isolated that matched MR60 peptide sequences. This cDNA was identical to that of ERGIC-53 and homologies with the animal lectin family of the galectins were noticed. Not all peptide sequences of MR60, however, were found in ERGIC-53, raising the possibility that another protein associated with ERGIC-53 may possess the lectin activity. Here, we provide the first direct evidence for a lectin function of ERGIC-53. Overexpressed ERGIC-53 binds to a mannose column in a calcium-dependent manner and also co-stains with mannosylated neoglycoprotein in a morphological binding assay. By using a sequential elution protocol we show that ERGIC-53 has selectivity for mannose and low affinity for glucose and GlcNAc, but no affinity for galactose. To experimentally address the putative homology of ERGIC-53 to leguminous lectins, a highly conserved protein family with an invariant asparagine essential for carbohydrate binding, we substituted the corresponding asparagine in ERGIC-53. This mutation, as well as a mutation affecting a second site in the putative carbohydrate recognition domain, abolished mannose-column binding and co-staining with mannosylated neoglycoprotein. These findings establish ERGIC-53 as a lectin and provide functional evidence for its relationship to leguminous lectins. Based on its monosaccharide specificity, domain organization, and recycling properties, we propose ERGIC-53 to function as a sorting receptor for glyco-proteins in the early secretory pathway.
33
Chen, Yanan, Harindra Vedala, Gregg P. Kotchey, Aymeric Audfray, Samy Cecioni, Anne Imberty, Sébastien Vidal e Alexander Star. "Detection of Lectins using Glyco-Functionalized Nanosensors". MRS Proceedings 1451 (2012): 191–96. http://dx.doi.org/10.1557/opl.2012.1291.
Testo completoAbstract (sommario):
ABSTRACTWe have used single-walled carbon nanotube field-effect transistor (SWNT-FET) and chemically converted graphene field-effect transistor (CCG-FET) devices to probe the interactions between carbohydrates and their recognition lectins. Porphyrin- and pyrene-based glycoconjugates were used as receptor molecules and the target lectins were two bacterial lectins that present different carbohydrate preference, namely PA-IL, PA-IIL from Pseudomonas aeruginosa and a plant lectin Concanavalin A. The specific binding between lectin and carbohydrate can be transduced to the change in FET device conductance. An initial study with SWNT-FET noncovalently functionalized with porphyrin-based glycoconjugates showed both good selectivity and sensitivity. To compare SWNT and CCG performance, pyrene- and porphyrin-based glycoconjugates were functionalized noncovalently on the surface of CCG-FET and SWNT-FET devices, which were then treated with non-specific and specific lectins. The responses were compared and rationalized using computer-aided models of carbon nanostructure/glycoconjugate interactions. Fluorescence microscopy, atomic force microscopy, UV-vis-NIR spectroscopy and Isothermal titration microcalorimetry (ITC) measurements were used to confirm the electrical results.
34
Reed, J. C., W. Tadmori, M. Kamoun, G. Koretzky e P. C. Nowell. "Suppression of interleukin 2 receptor acquisition by monoclonal antibodies recognizing the 50 KD protein associated with the sheep erythrocyte receptor on human T lymphocytes." Journal of Immunology 134, n. 3 (1 marzo 1985): 1631–39. http://dx.doi.org/10.4049/jimmunol.134.3.1631.
Testo completoAbstract (sommario):
Abstract Monoclonal antibodies OKT11A, 9.6, and 35.1 recognize epitopes on a 50000 dalton surface molecule (p50) identical to or closely associated with the sheep erythrocyte receptor (E receptor) on human T lymphocytes. These three antibodies were investigated for ability to inhibit T cell proliferation and interleukin 2 (IL 2) receptor acquisition (determined with anti-Tac antibody in an immunofluorescence assay) induced by the lectin mitogen phytohemagglutinin (PHA) or by the phorbol ester 12-O-tetradecanoyl-phorbol-13 acetate (TPA). OKT11A, 9.6, and 35.1 were found to suppress [3H]thymidine incorporation and IL 2 receptor acquisition stimulated by PHA but not by TPA. This inhibition was not attributable to a lag in kinetics, but was sustained throughout 4 to 5 days of culture. Because OKT11A and 9.6 have been reported to suppress lectin mitogen-induced IL 2 production, we attempted to overcome inhibition of proliferation with exogenous IL 2 (MLA144 supernatants or immunoaffinity-purified human IL 2). Adding IL 2 at the initiation of culture abrogated the suppressive effect of all three anti-p50 antibodies on proliferation and on the acquisition of IL 2 receptors, raising the possibility that IL 2 may up-regulate expression of its cellular receptor on human T lymphocytes. These data, together with previous reports, indicate that OKT11A, 9.6, and 35.1 suppress lectin mitogen-induced T cell proliferation by impairing both IL 2 elaboration and IL 2 receptor acquisition, and suggest that IL 2 may be capable, at least under some conditions, of increasing expression of IL 2 receptors on human T lymphocytes.
35
Sheikh, H., H. Yarwood, A. Ashworth e C. M. Isacke. "Endo180, an endocytic recycling glycoprotein related to the macrophage mannose receptor is expressed on fibroblasts, endothelial cells and macrophages and functions as a lectin receptor". Journal of Cell Science 113, n. 6 (15 marzo 2000): 1021–32. http://dx.doi.org/10.1242/jcs.113.6.1021.
Testo completoAbstract (sommario):
Endo180 was previously characterized as a novel, cell type specific, recycling transmembrane glycoprotein. This manuscript describes the isolation of a full length human Endo180 cDNA clone which was shown to encode a fourth member of a family of proteins comprising the macrophage mannose receptor, the phospholipase A(2) receptor and the DEC-205/MR6 receptor. This receptor family is unusual in that they contain 8–10 C-type lectin carbohydrate recognition domains in a single polypeptide backbone, however, only the macrophage mannose receptor had been shown to function as a lectin. Sequence analysis of Endo180 reveals that the second carbohydrate recognition domain has retained key conserved amino acids found in other functional C-type lectins. Furthermore, it is demonstrated that this protein displays Ca(2+)-dependent binding to N-acetylglucosamine but not mannose affinity columns. In order to characterize the physiological function of Endo180, a series of biochemical and morphological studies were undertaken. Endo180 is found to be predominantly expressed in vivo and in vitro on fibroblasts, endothelial cells and macrophages, and the distribution and post-translational processing in these cells is consistent with Endo180 functioning to internalize glycosylated ligands from the extracellular milieu for release in an endosomal compartment.
36
Watson, S. R., Y. Imai, C. Fennie, J. Geoffrey, M. Singer, S. D. Rosen e L. A. Lasky. "The complement binding-like domains of the murine homing receptor facilitate lectin activity." Journal of Cell Biology 115, n. 1 (1 ottobre 1991): 235–43. http://dx.doi.org/10.1083/jcb.115.1.235.
Testo completoAbstract (sommario):
The leukocyte homing receptor (HR), the endothelial leukocyte adhesion molecule, and gmp140/platelet activation-dependent granule membrane protein are members of a family of adhesion molecules, termed the lectin cell adhesion molecules (LEC-CAMS) which are unified by a multi-domain structure containing a lectin motif, an epidermal growth factor-like (egf) motif, and variable numbers of a complement binding-like (CB) motif. Previous data have indicated a predominant role for the lectin motif in cell adhesion directed by the LEC-CAMS, although the egf-like domain of the HR may also play a potential role in cell binding. While the role(s) of the CB domains in the LEC-CAMS is currently not understood, they have been hypothesized to act as rigid spacers or stalks for lectin and perhaps, egf domain presentation. In this paper, we analyze the functional characteristics of murine HR-IgG chimeras containing the lectin, lectin plus egf, and lectin plus egf plus CB domains. The Mel 14 mAb, an adhesion blocking antibody which recognizes a conformational determinant in the N-terminus of the HR lectin domain, shows a significantly decreased affinity for a HR construct which lacks the CB motifs, consistent with the possibility that the CB domains are involved with lectin domain structure. In agreement with this conjecture, HR mutants lacking the CB domains show a profound decrease in lectin-specific interaction with the carbohydrate polyphosphomannan ester, suggesting that the changes in Mel 14 affinity for the lectin domain are reflected in lectin functionality. Various assays investigating the interactions between the HR deletion mutants and the peripheral lymph node high endothelium, including cell blocking, immunohistochemical staining, and radioactively labeled ligand binding, all showed that removal of the CB domains results in a lack of HR adhesive function. These results imply that the CB domains of the HR, and, by analogy, the other members of the LEC-CAM family, may play important structural roles involving induction of lectin domain conformation and resultant functionality.
37
Richards, M. L., e D. H. Katz. "The binding of IgE to murine Fc epsilon RII is calcium-dependent but not inhibited by carbohydrate." Journal of Immunology 144, n. 7 (1 aprile 1990): 2638–46. http://dx.doi.org/10.4049/jimmunol.144.7.2638.
Testo completoAbstract (sommario):
Abstract Despite extensive study, little is known about the functions of the moderate affinity IgE receptors (Fc epsilon RII) on B cells. Recent cDNA and genomic cloning studies have demonstrated that, in contrast to other FcR, Fc epsilon RII is not a member of the Ig gene superfamily. Moreover, it uniquely expresses a region that is highly homologous with a membrane-associated, calcium-dependent binding lectin, the asialoglycoprotein receptor. We now report that the interaction between IgE and the Fc epsilon RII of murine B cells and macrophages requires calcium. Furthermore, as might be expected of asialoglycoprotein lectins, this binding was pH-dependent and resulted in ligand internalization. However, although 125I-Fc epsilon RII bound in a calcium-dependent manner to monosaccharide-agarose beads, high concentrations of mono- and disaccharides did not inhibit the interaction between either 125I-IgE and intact B cells or 125I-Fc epsilon RII (from surface-labeled B cells) and IgE-Sepharose. These results suggest that although murine Fc epsilon RII is a lectin, it is not strictly dependent upon IgE oligosaccharides for its binding to IgE.
38
Basu, Prabnab S., Pradip K. Datta e Tapash K. Datta. "Possible mechanism for the inhibition of lectin-erythrocyte interaction in presence of endogenous lectin receptor". Bioscience Reports 16, n. 6 (1 dicembre 1996): 453–58. http://dx.doi.org/10.1007/bf01198460.
Testo completoAbstract (sommario):
The presence of hydrophobic sites in the lectin-I molecule was indicated by hydrophobic probes like 1-anilinonapthalene-8-sulfonic acid (ANS), 2-p-toluidinyl napthalene-6-sulfonic acid (TNS), N-phenyl-1-napthylamine (NA) and rose bengal (RB). This was further confirmed by amino acid modifications in the hydrophobic region of the lectin-I molecule. The binding of ANS, TNS, NA and RB to lectin-I was affected in the presence of NaCl. The involvement of hydrophobic interactions in rice-bean lectin-I-endogenous lectin receptor (ELR) complex were indicated by alterations in the circular dichroism and fluorescence emission spectra. The percentage of β-conformation (55–63%) of lectin-I was decreased by addition of ELR. ELR on reacting with lectin-I reduced the fluorescence emissions of the hydrophobic probes while fluorescence emission of ANS, TNS, NA and RB were greatly enhanced in presence of lectin-I alone. N-aceyl-galactosamine did not change the fluorescence emissions of any of the hydrophobic probes in presence or in absence of lectin-I. This demonstrates that carbohydrate and hydrophobic sites may be different and non-interacting. It is proposed that the ELR in reacting with lectin-I, induced conformational changes in the lectin-I molecule and thereby affected its erythroagglutinating activity with human blood group “A” erythrocytes.
39
Pérez-Hernández, Jesus, Clarisa Retana-González, Espiridión Ramos-Martínez, José Cruz-Colín, Andrés Saralegui-Amaro, Gabriela Baltazar-Rosario, Concepción Gutiérrez-Ruíz, Gerardo Aristi-Urista e Rosario López-Vancell. "Entamoeba histolytica Trophozoites Interact with the c-Met Receptor at the Surface of Liver Origin Cells through the Gal/GalNAc Amoebic Lectin". Life 11, n. 9 (6 settembre 2021): 923. http://dx.doi.org/10.3390/life11090923.
Testo completoAbstract (sommario):
Amoebiasis in humans is caused by the protozoan parasite Entamoeba histolytica, which cytotoxic activity has been demonstrated on a wide variety of target cells. The process involves the adherence of the parasite to the cell, and such adherence is mediated by an amoebic surface lectin, known as Gal/GalNAc lectin. It is composed of heavy, intermediate, and light subunits. The carbohydrate recognition domain (CRD) has been identified within a cysteine-rich region in the lectin heavy subunit and has an amino acid sequence identity to the receptor-binding domain of hepatocyte growth factor (HGF). Recombinant CRD has been previously shown to compete with HGF for binding to the c-Met receptor IgG fusion protein. In the present study, we searched for evidence of interaction between the Gal/GalNAc lectin at the surface of trophozoites with the c-Met receptor expressed at the surface of HepG2 in coculture assays. Immunoprecipitation of the coculture lysate indicated interaction of the c-Met with a 60 kDa peptide recognized by antiamoebic lectin antibody. Colocalization of both molecules was detected by fluorescence confocal microscopy. Incubation of HepG2 cells with HGF before coculture with trophozoites prevents the cytotoxic effect caused by the parasites but not their adherence to the cells. Our results point to Gal/GalNAc lectin as a ligand of the c-Met receptor at the surface of HepG2 cells.
40
Abbott, W. Mark, e Philip G. Strange. "Partial purification of dopamine D2 receptors using lectin affinity columns". Bioscience Reports 5, n. 4 (1 aprile 1985): 303–8. http://dx.doi.org/10.1007/bf01116901.
Testo completoAbstract (sommario):
Dopamine D2 receptors, detected by [3H]spiperone Dopamine D2 receptors, detected by [3H]spiperone binding, were solubilized from bovine caudate nucleus by cholate/sodium chloride and were found to bind to wheat germ agglutinin immobilized on agarose. Specific elution could be achieved with N-acetylglucosamine whereas other sugars tested were inactive in this regard. The eluted preparation was enriched in solubilized receptors about sevenfold. The pharmaco-logical properties of the preparation were essentially unchanged by the lectin affinity purification procedure. The D2 dopamine receptor is therefore a glycoprotein. binding, were solubilized from bovine caudate nucJeus by cholate/sodium chloride and were found to bind to wheat germ agglutinin immobilized on agarose. Specific elution could be achieved with N-acetylglucosamine whereas other sugars tested were inactive in this regard. The eluted preparation was enriched in solubilized receptors about sevenfold. The pharmacological properties of the preparation were essentially unchanged by the lectin affinity purification procedure. The D2 dopamine receptor is therefore a glycoprotein.
41
Latham, Virginia H., Jeanette L. Ducut, Karolin Rostamiani, Helen H. Chun, Maria E. Lopez, Sabino Herrera e Steven B. Oppenheimer. "A rapid lectin receptor binding assay: comparative evaluation of sea urchin embryo cell surface lectin receptors". Acta Histochemica 97, n. 1 (gennaio 1995): 89–97. http://dx.doi.org/10.1016/s0065-1281(11)80209-6.
Testo completo
42
MCABEE, Douglas D., Xin JIANG e Kevin B. WALSH. "Lactoferrin binding to the rat asialoglycoprotein receptor requires the receptor's lectin properties". Biochemical Journal 348, n. 1 (9 maggio 2000): 113–17. http://dx.doi.org/10.1042/bj3480113.
Testo completoAbstract (sommario):
Lactoferrin binds to rat hepatic lectin 1 (RHL1), the major subunit of the asialoglycoprotein (ASGP) receptor, with high affinity, by a galactose-independent mechanism. To better understand the molecular basis of this novel interaction, we compared the binding of lactoferrin and asialo-orosomucoid (ASOR) to isolated rat hepatocytes and to purified ASGP receptors as a function of pH, Ca2+ and receptor acylation. Binding of 125I-lactoferrin and 125I-ASOR to isolated rat hepatocytes at 4 °C decreased sharply at pH < 6, following similar titration curves. Binding of 125I-lactoferrin and 125I-ASOR to hepatocytes was Ca2+-dependent. Binding increased progressively at ≥ 300 μM CaCl2, in the presence of 1 mM EDTA. Monensin treatment of hepatocytes, which causes hepatocytes to accumulate inactive ASGP receptors, reduced surface binding of 125I-lactoferrin and 125I-ASOR by 46 and 49%, respectively, with only a 16% loss of immunodetectable receptor protein from the cell surface. Finally, deacylation of purified ASGP receptors in vitro with 1 M hydroxylamine abolished receptor lectin activity as reflected by the loss of 125I-ASOR binding as well as the complete loss of specific 125I-lactoferrin binding. Treatment with 1 M Tris had no effect on binding of either ligand. We conclude from these data that galactose-independent lactoferrin binding to the ASGP receptor requires the receptor's carbohydrate-recognition domain to be in an active configuration. An active configuration is promoted by neutral pH and Ca2+, and also requires the receptor subunits to be acylated.
43
Dupuis, Gilles, e Marc Letellier. "Functional incorporation and preferred orientation of phytohemagglutinin receptor glycoproteins in phospholipid vesicles". Biochemistry and Cell Biology 65, n. 2 (1 febbraio 1987): 120–29. http://dx.doi.org/10.1139/o87-017.
Testo completoAbstract (sommario):
Porcine lymphocyte Phaseolus vulgaris phytohemagglutinin (PHA) receptor glycoproteins purified by affinity chromatography have been reassembled into vesicles made of phosphatidylcholine and phosphatidylserine by detergent (dodecyltrimethylammonium bromide) dialysis. The receptor glycoproteins were incorporated into the lipid vesicles in a nonselective manner with a yield of 65–70%. Vesicles containing the glycoproteins were sealed as evidenced by their impermeability to calcium ions, using quin 2 trapped inside the vesicles. The vesicles were agglutinated by PHA, suggesting that the saccharidic moiety of the reconstituted glycoproteins was, at least in part, oriented towads the extravesicular medium. This observation was further supported by the fact that the vesicles bound 125I-labeled PHA in a specific and saturable manner. At maximum amount of lectin bound, a ratio of 1.01 ± 0.05 μg of PHA per microgram glycoprotein incorporated was measured. When the binding data were analyzed by Scatchard plot, a downward concave profile was observed, suggestive of a positive cooperativity at low concentrations of lectin. The orientation of the reconstituted lectin receptor glycoproteins was determined by proteolytic treatments of labeled glycoproteins. The combined action of trypsin and chymotrypsin released, in the 120 000 × g supernatant, approximately 80% of label when 125I-tagged PHA receptor glycoproteins were incorporated into the vesicles. When the oligosaccharidic moieties of the receptor glycoproteins were specifically labeled, the simultaneous action of the two enzymes released approximately 70% of tritium labeling present in the reconstituted system. Taken together, these results suggest that the reconstituted PHA receptors are preferentially oriented into the phospholipid vesicles. The reconstituted PHA receptor glycoproteins competed effectively with cellular receptors in the assay of PHA-induced porcine lymphocyte activation. A 50% inhibition of [3H]thymidine incorporation was observed when 1 μg of glycoproteins in vesicles was added to the cultured cells, whereas vesicles alone had no effect at this (equivalent) concentration.
44
Ramos, Márcio Viana, Liezelotte Rezende Bomfim, Bandeira e Henri Debray. "Evidence of an endogenous lectin receptor in seeds of the legume Cratylia floribunda". Brazilian Journal of Plant Physiology 14, n. 3 (settembre 2002): 195–202. http://dx.doi.org/10.1590/s1677-04202002000300003.
Testo completoAbstract (sommario):
Cratylia floribunda seeds were ground and the clean crude saline extract was fractionated into albumin, globulin, prolamin, acidic and basic glutelin protein fractions. These protein fractions were examined for the presence of an endogenous lectin receptor by SDS-polyacrylamide gel electrophoresis, western blot, affinity chromatography on a Sepharose 4B-Cratylia floribunda (CFL) lectin column and kinetic analysis in real time by surface plasmon resonance (SPR). Prolamin was the richest protein fraction although very poor in haemagglutinating activity. Basic glutelin was far the less interesting fraction for lectin activity and protein content, even though this fraction contains considerable amounts of carbohydrates. Lectin was present in all protein fractions as estimated by haemagglutinating assays but basic glutelins were almost devoid of lectin activity. Except for prolamins, protein bands were detected by SDS-PAGE in all other fractions. Western blot using digoxigenin labelled Con A revealed a single band in the albumin, globulin, acidic and basic glutelin fractions, which specifically interacted with ConA. This band migrated exactly at the same position in such fractions and seemed to be more important in the globulins. Affinity chromatography of the protein fractions on a Sepharose-CFL column yielded a peak, which was only recovered after elution with acidic buffered solution or with an alpha-D-mannose solution and the monosaccharide was recognized by the lectin. These results were fully corroborated by real time interaction of immobilized CFL with the different soluble protein fractions suggesting the presence of a lectin receptor within albumins, globulins and basic glutelins. As a whole, the results suggest that the lectin from Cratylia floribunda recognizes a soluble endogenous glycosylated receptor through an interaction mediated by its carbohydrate-binding site.
45
Argayosa, A. M., F. F. Natividad, R. R. Matias e G. L. Enriquez. "Detection of Concannavalin a Receptors in Trophozoites and Cysts of Acanthamoeba sp. (W4) Philippine Isolate". Microscopy and Microanalysis 3, S2 (agosto 1997): 119–20. http://dx.doi.org/10.1017/s1431927600007480.
Testo completoAbstract (sommario):
Distribution of glucose and mannose moieties of Acanthamoeba sp. (W4) Philippine isolate was detected using fluorescem isothiocyanate (FITC)- labeled Concannavalin A (Con A) lectin. Green fluorescent patches around the plasma membrane of agglutinated trophozoites (Fig.1) were observed. Isolated Acanthamoeba cyst exhibited strong fluorescence on the cyst wall Brighter fluorescence was detected on the site of adherence between the Acanthamoeba (W4) cysts and trophozoites (Fig. 1,3). These lectin receptors were concentrated at the uroidal region of the trophozoite. The fluorescence, however, was absent in the newly forming hyaline cap (Fig.4). Upon addition of α -methyl-mannoside (0.5 M), Con A binding to sugar moieties in cyst and trophozoites was blocked and no fluorescence was observed.The binding specificity of Con A-FITC and Acanthamoeba cell surface mannose moieties demonstrate topographical distribution of lectin receptor sites. Ultrastructurally, ferritin-labeled Con A at cell adhesion sites showed clustering of lectin receptors. Occurrence of fluorescence in Naegleria sp. using Con A-FITC has been shown to concentrate at the uroidal region but no fluorescence was seen at the anterior of newly formed pseudopodia.
46
Szczykutowicz, Justyna. "Ligand Recognition by the Macrophage Galactose-Type C-Type Lectin: Self or Non-Self?—A Way to Trick the Host’s Immune System". International Journal of Molecular Sciences 24, n. 23 (3 dicembre 2023): 17078. http://dx.doi.org/10.3390/ijms242317078.
Testo completoAbstract (sommario):
The cells and numerous macromolecules of living organisms carry an array of simple and complex carbohydrates on their surface, which may be recognized by many types of proteins, including lectins. Human macrophage galactose-type lectin (MGL, also known as hMGL/CLEC10A/CD301) is a C-type lectin receptor expressed on professional antigen-presenting cells (APCs) specific to glycans containing terminal GalNAc residue, such as Tn antigen or LacdiNAc but also sialylated Tn antigens. Macrophage galactose-type lectin (MGL) exhibits immunosuppressive properties, thus facilitating the maintenance of immune homeostasis. Hence, MGL is exploited by tumors and some pathogens to trick the host immune system and induce an immunosuppressive environment to escape immune control. The aims of this article are to discuss the immunological outcomes of human MGL ligand recognition, provide insights into the molecular aspects of these interactions, and review the MGL ligands discovered so far. Lastly, based on the human fetoembryonic defense system (Hu-FEDS) hypothesis, this paper raises the question as to whether MGL-mediated interactions may be relevant in the development of maternal tolerance toward male gametes and the fetus.
47
Gregorio-Jauregui, Karla M., Susana A. Carrizales-Alvarez, Jorge E. Rivera-Salinas, Hened Saade, Jose L. Martinez, Raul G. Lopez e Anna Ilyina. "Immobilization of SA-α-2,6-Gal Receptors Related to Influenza on Magnetic Nanoparticles Coated with Chitosan". Advanced Materials Research 976 (giugno 2014): 19–24. http://dx.doi.org/10.4028/www.scientific.net/amr.976.19.
Testo completoAbstract (sommario):
Influenza infection is carried out due to the virus hemagglutinin recognizes host cell surface with terminal sialic acid (SA) linked receptors SA-α-2,6-Gal for human strain. Sambucus nigra lectin has structural similarity to the viral hemagglutinin. Magnetic nanoparticles (MNP) coated with chitosan can be used as support for the study of these receptors. The goal of this study was to extract the SA-α-2,6-Gal receptors of porcine trachea for their immobilization on magnetic nanoparticles coated with chitosan. The extraction was carried out based on affinity of Sambucus nigra lectin to SA-α-2,6-Gal receptors. It was possible to immobilize up to 76% of SA-α-2,6-Gal receptors, with a molecular weight at 88.4 kDa for more representative protein. The presence of the receptors was confirmed trough FTIR analysis. Magnetic functionalized nanoparticles showed superparamagnetic properties and an average diameter around 10 nm. These results may be used to evaluate the interaction between functionalized nanoparticles and specific lectin or hemagglutinin of influenza virus as model of study virus-receptor.
48
Geoffroy, J. S., e S. D. Rosen. "Demonstration that a lectin-like receptor (gp90MEL) directly mediates adhesion of lymphocytes to high endothelial venules of lymph nodes." Journal of Cell Biology 109, n. 5 (1 novembre 1989): 2463–69. http://dx.doi.org/10.1083/jcb.109.5.2463.
Testo completoAbstract (sommario):
Lymphocyte migration from the blood into most secondary lymphoid organs is initiated by a highly selective adhesive interaction with the endothelium of specialized blood vessels known as high endothelial venules (HEV). The propensity of lymphocytes to migrate to particular lymphoid organs is known as lymphocyte homing, and the receptors on lymphocytes that dictate interactions with HEV at particular anatomical sites are designated "homing receptors". Based upon antibody blockade experiments and cell-type distribution studies, a prominent candidate for the peripheral lymph node homing receptor in mouse is the approximately 90-kD cell surface glycoprotein (gp90MEL) recognized by the monoclonal antibody MEL-14. Previous work, including sequencing of a cDNA encoding for this molecule, supports the possibility that gp90MEL is a calcium-dependent lectin-like receptor. Here, we show that immunoaffinity-purified gp90MEL interacts in a sugar-inhibitable manner with sites on peripheral lymph node HEV and prevents attachment of lymphocytes. Lymphocyte attachment to HEV in Peyer's patches, a gut-associated lymphoid organ, is not affected by gp90MEL. The results demonstrate that gp90MEL, as a lectin-like receptor, directly bridges lymphocytes to the endothelium.
49
Jordinson, M., P. H. Deprez, R. J. Playford, S. Heal, T. C. Freeman, M. Alison e J. Calam. "Soybean lectin stimulates pancreatic exocrine secretion via CCK-A receptors in rats". American Journal of Physiology-Gastrointestinal and Liver Physiology 270, n. 4 (1 aprile 1996): G653—G659. http://dx.doi.org/10.1152/ajpgi.1996.270.4.g653.
Testo completoAbstract (sommario):
Rats fed raw soy flour (RSF) show pancreatic growth due to excessive cholecystokinin (CCK) release. Soybean trypsin inhibitors are implicated, but rats fed soybean lectin also showed pancreatic growth. Therefore, we studied the effect of soybean lectin on pancreatic protein secretion in anesthetized rats. Intraduodenal administration of 30 mg of RSF stimulated a 1-h integrated rise in pancreatic protein output of 2.2 +/- 1.1 mg/h (mean +/- SE) in rats with bile pancreatic (BP) juice returned to the duodenum. Selective removal of the lectin by affinity to N-acetyl-D-galactosamineagarose abolished the response (-0.1 +/- 0.2 mg/h). Adding back the 84 micrograms of lectin restored the output of 2.2 +/- 0.9 mg/h. With BP juice returned to the duodenum, 84 micrograms of lectin required the added presence of protein and protease inhibitors to have this effect. However, when BP juice was not returned, 84 micrograms of lectin given alone produced a pancreatic response of 3.2 +/- 1.3 mg/h. Plasma CCK concentrations rose significantly from 6.6 +/- 1.9 to 14.3 +/- 2.9 pmol/l, and the pancreatic response was abolished by CCK-A receptor blockade (0.0 +/- 0.1 mg/h). We conclude that soybean lectin plays a major role in the acute stimulation of pancreatic protein secretion by RSF. The lectin releases CCK and the effect is mediated by CCK-A receptors.
50
Sagar, Divya, Catherine Foss, Zafar Khan, Martin Pomper e Pooja Jain. "Lectin-targeted dendritic cell immunotherapies against experimental autoimmune encephalitis/multiple sclerosis (CAM5P.242)". Journal of Immunology 192, n. 1_Supplement (1 maggio 2014): 180.13. http://dx.doi.org/10.4049/jimmunol.192.supp.180.13.
Testo completoAbstract (sommario):
Abstract The molecular mechanisms of how circulating dendritic cells (DCs) access the CNS across the blood-brain barrier (BBB) remains to be investigated. During neuroinflammation, DCs transmigrate across the BBB in the presence of chemoattractants, particularly CCL2, and initiate immune response. We showed through near-infrared imaging that DC accumulation into lesions within the CNS correlated with severity of inflammation during experimental autoimmune encephalitis (EAE). Actin polymerization on DCs upon CCL2 exposure indicated a migratory phenotype. Transmigration of DCs was paracellular and more efficient than T cells in vitro. To selectively attenuate DC transmigration, we sought to study expression of DC specific C type lectin receptors- CD205 & CD206 (Type I), CD207, -209, -303, CLEC4A, -9A, -10A & -12A (Type II). Different DC subsets- myeloid (mDC), plasmacytoid (pDC) and monocyte-derived (MDDC) had a unique enrichment of lectin receptors and each subset utilized a different receptor to adhere and transmigrate in the presence of CCL2. Phosphoproteomics revealed that these receptors when triggered, activate molecular events known to be involved in actin dynamics, thus substantiating their role in DC transmigration. Importantly, in EAE mice these lectins were validated targets for inhibiting DC transmigration. Thus, the prospect of selectively regulating DC entry into the CNS will open up new treatments against disease pathogenesis and propagation in multiple sclerosis.