Journal articles: 'Membrane bound proteins'

1

Nishikiori, Masaki, Koji Dohi, Masashi Mori, Tetsuo Meshi, Satoshi Naito, and Masayuki Ishikawa. "Membrane-Bound Tomato Mosaic Virus Replication Proteins Participate in RNA Synthesis and Are Associated with Host Proteins in a Pattern Distinct from Those That Are Not Membrane Bound." Journal of Virology 80, no. 17 (September 1, 2006): 8459–68. http://dx.doi.org/10.1128/jvi.00545-06.

Full text

Abstract:

ABSTRACT Extracts of vacuole-depleted, tomato mosaic virus (ToMV)-infected plant protoplasts contained an RNA-dependent RNA polymerase (RdRp) that utilized an endogenous template to synthesize ToMV-related positive-strand RNAs in a pattern similar to that observed in vivo. Despite the fact that only minor fractions of the ToMV 130- and 180-kDa replication proteins were associated with membranes, the RdRp activity was exclusively associated with membranes. A genome-sized, negative-strand RNA template was associated with membranes and was resistant to micrococcal nuclease unless treated with detergents. Non-membrane-bound replication proteins did not exhibit RdRp activity, even in the presence of ToMV RNA. While the non-membrane-bound replication proteins remained soluble after treatment with Triton X-100, the same treatment made the membrane-bound replication proteins in a form that precipitated upon low-speed centrifugation. On the other hand, the detergent lysophosphatidylcholine (LPC) efficiently solubilized the membrane-bound replication proteins. Upon LPC treatment, the endogenous template-dependent RdRp activity was reduced and exogenous ToMV RNA template-dependent RdRp activity appeared instead. This activity, as well as the viral 130-kDa protein and the host proteins Hsp70, eukaryotic translation elongation factor 1A (eEF1A), TOM1, and TOM2A copurified with FLAG-tagged viral 180-kDa protein from LPC-solubilized membranes. In contrast, Hsp70 and only small amounts of the 130-kDa protein and eEF1A copurified with FLAG-tagged non-membrane-bound 180-kDa protein. These results suggest that the viral replication proteins are associated with the intracellular membranes harboring TOM1 and TOM2A and that this association is important for RdRp activity. Self-association of the viral replication proteins and their association with other host proteins may also be important for RdRp activity.

APA, Harvard, Vancouver, ISO, and other styles

2

YAMAMOTO, Eiji. "Interaction of Membrane Bound Proteins with Phosphoinositide-containing Membranes." Seibutsu Butsuri 61, no. 4 (2021): 253–54. http://dx.doi.org/10.2142/biophys.61.253.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

ARGOS, Patrick, J. K. Mohana RAO, and Paul A. HARGRAVE. "Structural Prediction of Membrane-Bound Proteins." European Journal of Biochemistry 128, no. 2-3 (March 3, 2005): 565–75. http://dx.doi.org/10.1111/j.1432-1033.1982.tb07002.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

4

Ulbrich, Maximilian H., and Ehud Y. Isacoff. "Subunit counting in membrane-bound proteins." Nature Methods 4, no. 4 (March 18, 2007): 319–21. http://dx.doi.org/10.1038/nmeth1024.

Full text

APA, Harvard, Vancouver, ISO, and other styles

5

Rosiere, T. K., J. A. Marrs, and G. B. Bouck. "A 39-kD plasma membrane protein (IP39) is an anchor for the unusual membrane skeleton of Euglena gracilis." Journal of Cell Biology 110, no. 4 (April 1, 1990): 1077–88. http://dx.doi.org/10.1083/jcb.110.4.1077.

Full text

Abstract:

The major integral plasma membrane protein (IP39) of Euglena gracilis was radiolabeled, peptide mapped, and dissected with proteases to identify cytoplasmic domains that bind and anchor proteins of the cell surface. When plasma membranes were radioiodinated and extracted with octyl glucoside, 98% of the extracted label was found in IP39 or the 68- and 110-kD oligomers of IP39. The octyl glucoside extracts were incubated with unlabeled cell surface proteins immobilized on nitrocellulose (overlays). Radiolabel from the membrane extract bound one (80 kD) of the two (80 and 86 kD) major membrane skeletal protein bands. Resolubilization of the bound label yielded a radiolabeled polypeptide identical in Mr to IP39. Intact plasma membranes were also digested with papain before or after radioiodination, thereby producing a cytoplasmically truncated IP39. The octyl glucoside extract of truncated IP39 no longer bound to the 80-kD membrane skeletal protein in the nitrocellulose overlays. EM of intact or trypsin digested plasma membranes incubated with membrane skeletal proteins under stringent conditions similar to those used in the nitrocellulose overlays revealed a partially reformed membrane skeletal layer. Little evidence of a membrane skeletal layer was found, however, when plasma membranes were predigested with papain before reassociation. A candidate 80-kD binding domain of IP39 has been tentatively identified as a peptide fragment that was present after trypsin digestion of plasma membranes, but was absent after papain digestion in two-dimensional peptide maps of IP39. Together, these data suggest that the unique peripheral membrane skeleton of Euglena binds to the plasma membrane through noncovalent interactions between the major 80-kD membrane skeletal protein and a small, papain sensitive cytoplasmic domain of IP39. Other (62, 51, and 25 kD) quantitatively minor peripheral proteins also interact with IP39 on the nitrocellulose overlays, and the possible significance of this binding is discussed.

APA, Harvard, Vancouver, ISO, and other styles

6

Stochaj, W. R., T. Berkelman, and N. Laird. "Staining Membrane-Bound Proteins with Ponceau S." Cold Spring Harbor Protocols 2006, no. 28 (October 1, 2006): pdb.prot4543. http://dx.doi.org/10.1101/pdb.prot4543.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Stochaj, W. R., T. Berkelman, and N. Laird. "Staining Membrane-Bound Proteins with Colloidal Gold." Cold Spring Harbor Protocols 2006, no. 28 (October 1, 2006): pdb.prot4545. http://dx.doi.org/10.1101/pdb.prot4545.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

Sapp, Kayla, and Lutz Maibaum. "Fluctuation-Induced Interactions between Membrane-Bound Proteins." Biophysical Journal 108, no. 2 (January 2015): 543a. http://dx.doi.org/10.1016/j.bpj.2014.11.2980.

Full text

APA, Harvard, Vancouver, ISO, and other styles

9

Bilodeau, Diane, Sylvie Lamy, Richard R. Desrosiers, Denis Gingras, and Richard Béliveau. "Regulation of Rho protein binding to membranes by rhoGDI: inhibition of releasing activity by physiological ionic conditions." Biochemistry and Cell Biology 77, no. 1 (March 1, 1999): 59–69. http://dx.doi.org/10.1139/o99-004.

Full text

Abstract:

The Rho GDP dissociation inhibitor (GDI) is an ubiquitously expressed regulatory protein involved in the cycling of Rho proteins between membrane-bound and soluble forms. Here, we characterized the Rho solubilization activity of a glutathione S-transferase (GST) - GDI fusion protein in a cell-free system derived from rat kidney. Addition of GST-GDI to kidney brush border membranes resulted in the specific release of Cdc42 and RhoA from the membranes, while RhoB and Ras were not extracted. The release of Cdc42 and RhoA by GST-GDI was dose dependent and saturable with about 50% of both RhoA and Cdc42 extracted. The unextracted Rho proteins were tightly bound to membranes and could not be solubilized by repeated GST-GDI treatment. These results demonstrated that kidney brush border membranes contained two populations of RhoA and Cdc42. Furthermore, the GST-GDI solubilizing activity on membrane-bound Cdc42 and RhoA was abolished at physiological conditions of salt and temperature in all tissues examined. When using bead-immobilized GST-GDI, KCl did not reduced the binding of Rho proteins. However, washing brush border membranes with KCl prior treatment by GST-GDI inhibited the extraction of Rho proteins. Taken together, these results suggest that the binding of GDI to membrane-bound Cdc42 and RhoA occurs easily under physiological ionic strength conditions, but a complementary factor is required to extract these proteins from membranes. These observations suggest that the shuttling activity of GDI upon Rho proteins could be normally downregulated under physiological conditions.Key words: rhoGDI, rho proteins, ionic strength, kidney.

APA, Harvard, Vancouver, ISO, and other styles

10

Harder, T., R. Kellner, R. G. Parton, and J. Gruenberg. "Specific release of membrane-bound annexin II and cortical cytoskeletal elements by sequestration of membrane cholesterol." Molecular Biology of the Cell 8, no. 3 (March 1997): 533–45. http://dx.doi.org/10.1091/mbc.8.3.533.

Full text

Abstract:

Annexin II is an abundant protein which is present in the cytosol and on the cytoplasmic face of plasma membrane and early endosomes. It is generally believed that this association occurs via Ca(2+)-dependent binding to lipids, a mechanism typical for the annexin protein family. Although previous studies have shown that annexin II is involved in early endosome dynamics and organization, the precise biological role of the protein is unknown. In this study, we found that approximately 50% of the total cellular annexin was associated with membranes in a Ca(2+)-independent manner. This binding was extremely tight, since it resisted high salt and, to some extent, high pH treatments. We found, however, that membrane-associated annexin II could be quantitatively released by low concentrations of the cholesterol-sequestering agents filipin and digitonin. Both treatments released an identical and limited set of proteins but had no effects on other membrane-associated proteins. Among the released proteins, we identified, in addition to annexin II itself, the cortical cytoskeletal proteins alpha-actinin, ezrin and moesin, and membrane-associated actin. Our biochemical and immunological observations indicate that these proteins are part of a complex containing annexin II and that stability of the complex is sensitive to cholesterol sequestering agents. Since annexin II is tightly membrane-associated in a cholesterol-dependent manner, and since it seems to interact physically with elements of the cortical actin cytoskeleton, we propose that the protein serves as interface between membranes containing high amounts of cholesterol and the actin cytoskeleton.

APA, Harvard, Vancouver, ISO, and other styles

11

Mallet, W. G., and F. M. Brodsky. "A membrane-associated protein complex with selective binding to the clathrin coat adaptor AP1." Journal of Cell Science 109, no. 13 (December 15, 1996): 3059–68. http://dx.doi.org/10.1242/jcs.109.13.3059.

Full text

Abstract:

Adaptors are the membrane-binding components of clathrin-coated vesicles. The interaction of the trans-Golgi coat adaptor AP1 with membrane-associated proteins was analyzed by affinity chromatography. Proteins of 83 and 52 kDa bound specifically to the core domain of AP1 and showed no interaction with AP2 or other clathrin-coated vesicle proteins. The AP1-binding proteins were tightly membrane-associated, though behaved as peripheral membrane proteins. They were detected in membranes depleted of clathrin-coated vesicles and not in coated vesicles, suggesting that the interaction of these proteins with AP1 may precede coated vesicle budding. Co-fractionation of the AP1-binding proteins with trans-Golgi network membrane was also observed. Upon gel filtration, both AP1-binding proteins eluted in a high molecular mass complex which was labile at high concentrations of Tris. The 83 kDa protein bound to AP1 affinity resin in the absence of the 52 kDa protein. In contrast, the separated 52 kDa protein did not bind AP1, suggesting that the 83 kDa protein is the AP1-binding component of the complex. Characterization of this protein complex defines a novel membrane-associated component that specifically interacts with AP1 and may contribute to its function in forming clathrin-coated vesicles.

APA, Harvard, Vancouver, ISO, and other styles

12

Ward, Elizabeth, and Trish Berger. "Binding of porcine sperm plasma membrane proteins to sheep, hamster and mouse oocyte plasma membrane." Zygote 8, no. 2 (May 2000): 181–87. http://dx.doi.org/10.1017/s0967199400000964.

Full text

Abstract:

Four porcine sperm plasma membrane proteins were previously identified as putative ligands for the oocyte plasma membrane. The present study examined the binding of these proteins and two additional porcine sperm membrane proteins to oocytes from sheep, mice and hamsters as a first step in assessing potential conservation of these putative sperm ligands across species and across mammalian orders. Plasma membrane vesicles were isolated from porcine sperm, solubilised, and the proteins separated by one-dimensional gel electrophoresis. The 7, 27, 39 and 62 kDa porcine sperm protein bands demonstrating predominant binding of the porcine oocyte plasma membrane on ligand blots, a 90 kDa protein band demonstrating minor binding, and a 97 kDa protein band that did not bind the oocyte plasma membrane probe were electroeluted. Proteins were biotinylated, and incubated with zona-free oocytes. Bound biotinylated protein was labelled with fluorescent avidin and the oocytes examined with a confocal microscope. The 7 kDa, 27 kDa and the 39 kDa proteins bound to the sheep oocytes but not to a majority of the hamster or mouse oocytes. The 62 kDa protein bound to sheep oocytes and mouse oocytes but not to a majority of the hamster oocytes. The 90 kDa protein bound to oocytes from all three species. The 97 kDa protein, which did not recognise the porcine oocyte probe on a Western ligand blot, did not bind to oocytes from any species and served as a negative control. These observations are consistent with significant conservation of molecule and function among species within the same mammalian order. Hence, one species may be a good model for other species from the same order. Only limited conservation of binding activity of porcine sperm plasma membrane proteins to rodent oocytes was observed, suggesting a greater divergence either in molecular structure or in function among species from different orders.

APA, Harvard, Vancouver, ISO, and other styles

13

Rupar, C. Anthony, and Jeffery D. Whitehall. "The preparation of rat liver lysosome membranes. Several membrane proteins contain complex oligosaccharides." Biochemistry and Cell Biology 66, no. 4 (April 1, 1988): 273–78. http://dx.doi.org/10.1139/o88-036.

Full text

Abstract:

Lysosome membranes were isolated, and membrane proteins and glycoproteins were characterized by electrophoresis and lectin probes of nitrocellulose blots. Rat liver lysosomes were isolated on a discontinuous metrizamide gradient and characterized by subcellular marker enzymes. Lysosomes were lysed by hypotonic freeze–thaw shock and membranes were isolated. The release of β-N-acetylhexosaminidase was used to monitor the disruption of the lysosomes. Proteins of lysosome membranes were analyzed by sodium dodecyl sulfate – polyacrylamide gel electrophoresis. There were at least 30 proteins present and several were glycoproteins. Nitrocellulose blots of lysosome membrane proteins were probed with a panel of lectins, including concanavalin A, Ulex europaeus agglutinin I, Lotus tetragonolobus agglutinin, soybean agglutinin, peanut agglutinin, and Ricinus communis agglutinin I. Peanut agglutinin and Ricinus communis agglutinin I binding were also examined after neuramidase treatment of lysosome membranes. Ten proteins bound concanavalin A, and neuraminidase pretreatment revealed six proteins that bound Ricinus communis agglutinin I and three proteins that bound peanut agglutinin. The other lectins tested did not bind to any lysosome membrane proteins. These results indicate that lysosome membranes contain several glycoproteins, some of which contain sialic acid terminating complex oligosaccharides.

APA, Harvard, Vancouver, ISO, and other styles

14

Stange, J., and S. Mitzner. "A Carrier-Mediated Transport of Toxins in a Hybrid Membrane. Safety Barrier between a Patients Blood and a Bioartificial Liver." International Journal of Artificial Organs 19, no. 11 (November 1996): 677–91. http://dx.doi.org/10.1177/039139889601901109.

Full text

Abstract:

Combination of detoxifying liver support systems with liver cell bioreactors may have additional benefits for the treatment of liver failure due to the replacement of known and unknown metabolic activities of the liver. However, the problem of side effects and possible risks caused by the use of animal hepatocytes or hepatoma cells remains unsolved which underlines the need of a safety barrier between the patients blood and the extracorporeal bioreactor. Passive filters do not meet the requirements of such membranes, because in liver failure desired and undesired molecules in the patients blood share similar physicochemical properties. That challanges the developement of biologically designed separation membranes. A hybrid membrane is formed by implementation of transport proteins into a highly permeable hollow fiber. The transport of free solutes and albumin bound toxins is tested in vitro in comparison with conventional high flux membranes. The transport characteristics for tightly albumin bound toxins are significantly improved for the hybrid membrane. The transport of albumin bound toxins across the membrane is not associated with albumin. The selectivity of the transport is evaluated in vivo. No significant loss of middle molecular weight hormones attached to other carrier proteins was observed. Neither transport of immunologically relevant proteins across the membrane nor loss of valuable proteins was measured. Also in vivo, a significant reduction of protein bound toxins and a transport of metabolically relevant solutes, like amino acids, was shown. The presented hybrid membrane may be used like an “intellegent membrane” as a safety barrier between the patients blood and cell devices.

APA, Harvard, Vancouver, ISO, and other styles

15

Mirza, Shama P., Brian D. Halligan, Andrew S. Greene, and Michael Olivier. "Improved method for the analysis of membrane proteins by mass spectrometry." Physiological Genomics 30, no. 1 (June 2007): 89–94. http://dx.doi.org/10.1152/physiolgenomics.00279.2006.

Full text

Abstract:

Membrane-bound and membrane-associated proteins are difficult to analyze by mass spectrometry, since the association with lipids impedes the isolation and solubilization of the proteins in buffers suitable for mass spectrometry and the efficient generation of positively charged peptide ions by electrospray ionization. Current methods mostly utilize detergents for the isolation of proteins from membranes. In this study, we present an improved detergent-free method for the isolation and mass spectrometric identification of membrane-bound and membrane-associated proteins. We delipidate proteins from the membrane bilayer by chloroform extraction to overcome dissolution and ionization problems during analysis. Comparison of our results to results obtained by direct tryptic digestion of insoluble membrane pellets identifies an increased number of membrane proteins, and a higher quality of the resulting mass spectral data.

APA, Harvard, Vancouver, ISO, and other styles

16

Vidilaseris, Keni, Alexandros Kiriazis, Ainoleena Turku, Ayman Khattab, Niklas G. Johansson, Teppo O. Leino, Paula S. Kiuru, et al. "Asymmetry in catalysis by Thermotoga maritima membrane-bound pyrophosphatase demonstrated by a nonphosphorus allosteric inhibitor." Science Advances 5, no. 5 (May 2019): eaav7574. http://dx.doi.org/10.1126/sciadv.aav7574.

Full text

Abstract:

Membrane-bound pyrophosphatases are homodimeric integral membrane proteins that hydrolyze pyrophosphate into orthophosphates, coupled to the active transport of protons or sodium ions across membranes. They are important in the life cycle of bacteria, archaea, plants, and parasitic protists, but no homologous proteins exist in vertebrates, making them a promising drug target. Here, we report the first nonphosphorus allosteric inhibitor of the thermophilic bacterium Thermotoga maritima membrane-bound pyrophosphatase and its bound structure together with the substrate analog imidodiphosphate. The unit cell contains two protein homodimers, each binding a single inhibitor dimer near the exit channel, creating a hydrophobic clamp that inhibits the movement of β-strand 1–2 during pumping, and thus prevents the hydrophobic gate from opening. This asymmetry of inhibitor binding with respect to each homodimer provides the first clear structural demonstration of asymmetry in the catalytic cycle of membrane-bound pyrophosphatases.

APA, Harvard, Vancouver, ISO, and other styles

17

Karotki, Lena, Juha T. Huiskonen, Christopher J. Stefan, Natasza E. Ziółkowska, Robyn Roth, Michal A. Surma, Nevan J. Krogan, et al. "Eisosome proteins assemble into a membrane scaffold." Journal of Cell Biology 195, no. 5 (November 28, 2011): 889–902. http://dx.doi.org/10.1083/jcb.201104040.

Full text

Abstract:

Spatial organization of membranes into domains of distinct protein and lipid composition is a fundamental feature of biological systems. The plasma membrane is organized in such domains to efficiently orchestrate the many reactions occurring there simultaneously. Despite the almost universal presence of membrane domains, mechanisms of their formation are often unclear. Yeast cells feature prominent plasma membrane domain organization, which is at least partially mediated by eisosomes. Eisosomes are large protein complexes that are primarily composed of many subunits of two Bin–Amphiphysin–Rvs domain–containing proteins, Pil1 and Lsp1. In this paper, we show that these proteins self-assemble into higher-order structures and bind preferentially to phosphoinositide-containing membranes. Using a combination of electron microscopy approaches, we generate structural models of Pil1 and Lsp1 assemblies, which resemble eisosomes in cells. Our data suggest that the mechanism of membrane organization by eisosomes is mediated by self-assembly of its core components into a membrane-bound protein scaffold with lipid-binding specificity.

APA, Harvard, Vancouver, ISO, and other styles

18

Горохова, Viktoriya Gorokhova, Корякина, Larisa Koryakina, Бабушкина, Inna Babushkina, Сергеева, et al. "LEVEL OF MEMBRANE-BOUND HEMOGLOBIN AND RED-CELL MEMBRANE PROTEINS IN PATIENTS WITH ESSENTIAL HYPERTENSION COMPLICATED AND NOT COMPLICATED WITH METABOLIC SYNDROME." Бюллетень Восточно-Сибирского научного центра Сибирского отделения Российской академии медицинских наук 1, no. 4 (November 28, 2016): 61–67. http://dx.doi.org/10.12737/22960.

Full text

Abstract:

We studied the effect of different levels of membrane-bound hemoglobin on the level of red-cell membrane proteins and also their interrelation in patients with essential hypertension with and without metabolic syndrome. It was found that high membrane-bound hemoglobin is closely related to the low level of high-density lipoproteins and high level of low-density lipoproteins in patients with essential hypertension complicated with metabolic syndrome. In patients with essential hypertension not complicated with metabolic syndrome high membrane-bound hemoglobin is related to the increased prothrombin time and decreased blood urea nitrogen. In patients with essential hypertension com-plicated with metabolic syndrome high membrane-bound hemoglobin significantly influences the level of membrane contractile proteins (actin, tropomiosine). In patients with essential hypertension without metabolic syndrome high membrane-bound hemoglobin is accompanied by the decrease of structural and integral membrane proteins levels (anion-transport protein and protein 4.1). As the result of quantitative changes in these proteins and change in their interrelations in patients with ssential hypertension complicated with metabolic syndrome more intensive disorders of structural and functional organization of red-cell membrane can appear.

APA, Harvard, Vancouver, ISO, and other styles

19

Snead, Wilton T., Carl C. Hayden, Avinash K. Gadok, Chi Zhao, Eileen M. Lafer, Padmini Rangamani, and Jeanne C. Stachowiak. "Membrane fission by protein crowding." Proceedings of the National Academy of Sciences 114, no. 16 (April 3, 2017): E3258—E3267. http://dx.doi.org/10.1073/pnas.1616199114.

Full text

Abstract:

Membrane fission, which facilitates compartmentalization of biological processes into discrete, membrane-bound volumes, is essential for cellular life. Proteins with specific structural features including constricting rings, helical scaffolds, and hydrophobic membrane insertions are thought to be the primary drivers of fission. In contrast, here we report a mechanism of fission that is independent of protein structure—steric pressure among membrane-bound proteins. In particular, random collisions among crowded proteins generate substantial pressure, which if unbalanced on the opposite membrane surface can dramatically increase membrane curvature, leading to fission. Using the endocytic protein epsin1 N-terminal homology domain (ENTH), previously thought to drive fission by hydrophobic insertion, our results show that membrane coverage correlates equally with fission regardless of the hydrophobicity of insertions. Specifically, combining FRET-based measurements of membrane coverage with multiple, independent measurements of membrane vesiculation revealed that fission became spontaneous as steric pressure increased. Further, fission efficiency remained equally potent when helices were replaced by synthetic membrane-binding motifs. These data challenge the view that hydrophobic insertions drive membrane fission, suggesting instead that the role of insertions is to anchor proteins strongly to membrane surfaces, amplifying steric pressure. In line with these conclusions, even green fluorescent protein (GFP) was able to drive fission efficiently when bound to the membrane at high coverage. Our conclusions are further strengthened by the finding that intrinsically disordered proteins, which have large hydrodynamic radii yet lack a defined structure, drove fission with substantially greater potency than smaller, structured proteins.

APA, Harvard, Vancouver, ISO, and other styles

20

KASAMO, Kunihiro. "Reconstitution of Plant Membrane Bound Proteins into Liposomes." Kagaku To Seibutsu 32, no. 12 (1994): 797–810. http://dx.doi.org/10.1271/kagakutoseibutsu1962.32.797.

Full text

APA, Harvard, Vancouver, ISO, and other styles

21

Stochaj, W. R., T. Berkelman, and N. Laird. "Staining Membrane-Bound Proteins with Coomassie Blue R250." Cold Spring Harbor Protocols 2006, no. 28 (October 1, 2006): pdb.prot4544. http://dx.doi.org/10.1101/pdb.prot4544.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

Barklis, E. "Structural analysis of membrane-bound retrovirus capsid proteins." EMBO Journal 16, no. 6 (March 15, 1997): 1199–213. http://dx.doi.org/10.1093/emboj/16.6.1199.

Full text

APA, Harvard, Vancouver, ISO, and other styles

23

Barros, Marilia, Robert A. Dick, Siddhartha A. K. Datta, Volker M. Vogt, Alan Rein, Mathias Lösche, and Hirsh Nanda. "Structural Comparison of Membrane-Bound Retroviral Gag Proteins." Biophysical Journal 108, no. 2 (January 2015): 559a. http://dx.doi.org/10.1016/j.bpj.2014.11.3065.

Full text

APA, Harvard, Vancouver, ISO, and other styles

24

Do Rego Barros, Marilia C., Siddartha A. K. Datta, Alan Rein, Mathias Losche, and Hirsh Nanda. "Conformational Differences in Membrane Bound Retroviral Gag Proteins." Biophysical Journal 104, no. 2 (January 2013): 64a. http://dx.doi.org/10.1016/j.bpj.2012.11.389.

Full text

APA, Harvard, Vancouver, ISO, and other styles

25

Wen, Yi, Robert A. Dick, Gerald W. Feigenson, and Volker M. Vogt. "Effects of Membrane Charge and Order on Membrane Binding of the Retroviral Structural Protein Gag." Journal of Virology 90, no. 20 (August 10, 2016): 9518–32. http://dx.doi.org/10.1128/jvi.01102-16.

Full text

Abstract:

ABSTRACTThe retroviral structural protein Gag binds to the inner leaflet of the plasma membrane (PM), and many cellular proteins do so as well. We used Rous sarcoma virus (RSV) Gag together with membrane sensors to study the principles governing peripheral protein membrane binding, including electrostatics, specific recognition of phospholipid headgroups, sensitivity to phospholipid acyl chain compositions, preference for membrane order, and protein multimerization. We used anin vitroliposome-pelleting assay to test protein membrane binding properties of Gag, the well-characterized MARCKS peptide, a series of fluorescent electrostatic sensor proteins (mNG-KRn), and the specific phosphatidylserine (PS) binding protein Evectin2. RSV Gag and mNG-KRn bound well to membranes with saturated and unsaturated acyl chains, whereas the MARCKS peptide and Evectin2 preferentially bound to membranes with unsaturated acyl chains. To further discriminate whether the primary driving force for Gag membrane binding is electrostatic interactions or preference for membrane order, we measured protein binding to giant unilamellar vesicles (GUVs) containing the same PS concentration in both disordered (Ld) and ordered (Lo) phases. RSV Gag and mNG-KRn membrane association followed membrane charge, independent of membrane order. Consistent with pelleting data, the MARCKS peptide showed preference for the Ld domain. Surprisingly, the PS sensor Evectin2 bound to the PS-rich Ld domain with 10-fold greater affinity than to the PS-rich Lo domain. In summary, we found that RSV Gag shows no preference for membrane order, while proteins with reported membrane-penetrating domains show preference for disordered membranes.IMPORTANCERetroviral particles assemble on the PM and bud from infected cells. Our understanding of how Gag interacts with the PM and how different membrane properties contribute to overall Gag assembly is incomplete. This study examined how membrane charge and membrane order influence Gag membrane association. Consistent with previous work on RSV Gag, we report here that electrostatic interactions provide the primary driving force for RSV Gag membrane association. Using phase-separated GUVs with known lipid composition of the Ld and Lo phases, we demonstrate for the first time that RSV Gag is sensitive to membrane charge but not membrane order. In contrast, the cellular protein domain MARCKS and the PS sensor Evectin2 show preference for disordered membranes. We also demonstrate how to define GUV phase composition, which could serve as a tool in future studies of protein membrane interactions.

APA, Harvard, Vancouver, ISO, and other styles

26

López-Aparicio, P., M. N. Recio, J. C. Prieto, and M. A. Pérez-Albarsanz. "Role of lindane in membranes. Effects on membrane fluidity and activity of membrane-bound proteins." Bioscience Reports 14, no. 3 (June 1, 1994): 131–38. http://dx.doi.org/10.1007/bf01240245.

Full text

Abstract:

The influence of lindane (gamma-hexachlorocyclohexane) on fluidity of plasma membranes from rat renal cortical tubules has been investigated. Preincubation with lindane increased membrane fluidity. This effect was accompanied by (i) a decrease in the transport of glucose with regard to the controls and (ii) an inhibition of the β-adrenergic stimulatory activity upon cyclic AMP accumulation. However, a significant decrease of the membrane fluidity was found when rats were injected with lindane for 12 days. The injection of lindane exerted the opposite effect on the membrane proteins, the glucose transporter and the β-adrenergic receptor, enhancing the glucose uptake and increasing the isoproterenol-stimulated cycle AMP accumulation. A possible explanation of the difference could involve a resistance to membrane disordering by lindane through a regulatory mechanism that would balance the activity of many lindane-sensitive proteins in insecticide-injected rats.

APA, Harvard, Vancouver, ISO, and other styles

27

Luoto, Heidi H., Erika Nordbo, Anssi M. Malinen, Alexander A. Baykov, and Reijo Lahti. "Evolutionarily divergent, Na+-regulated H+-transporting membrane-bound pyrophosphatases." Biochemical Journal 467, no. 2 (April 2, 2015): 281–91. http://dx.doi.org/10.1042/bj20141434.

Full text

Abstract:

Membrane-bound pyrophosphatase (mPPases) of various types consume pyrophosphate (PPi) to drive active H+ or Na+ transport across membranes. H+-transporting PPases are divided into phylogenetically distinct K+-independent and K+-dependent subfamilies. In the present study, we describe a group of 46 bacterial proteins and one archaeal protein that are only distantly related to known mPPases (23%–34% sequence identity). Despite this evolutionary divergence, these proteins contain the full set of 12 polar residues that interact with PPi, the nucleophilic water and five cofactor Mg2+ ions found in ‘canonical’ mPPases. They also contain a specific lysine residue that confers K+ independence on canonical mPPases. Two of the proteins (from Chlorobium limicola and Cellulomonas fimi) were expressed in Escherichia coli and shown to catalyse Mg2+-dependent PPi hydrolysis coupled with electrogenic H+, but not Na+ transport, in inverted membrane vesicles. Unique features of the new H+-PPases include their inhibition by Na+ and inhibition or activation, depending on PPi concentration, by K+ ions. Kinetic analyses of PPi hydrolysis over wide ranges of cofactor (Mg2+) and substrate (Mg2–PPi) concentrations indicated that the alkali cations displace Mg2+ from the enzyme, thereby arresting substrate conversion. These data define the new proteins as a novel subfamily of H+-transporting mPPases that partly retained the Na+ and K+ regulation patterns of their precursor Na+-transporting mPPases.

APA, Harvard, Vancouver, ISO, and other styles

28

Masumoto, Naoko, Thomas Lanyon-Hogg, Ursula R. Rodgers, Antonios D. Konitsiotis, Anthony I. Magee, and Edward W. Tate. "Membrane bound O-acyltransferases and their inhibitors." Biochemical Society Transactions 43, no. 2 (April 1, 2015): 246–52. http://dx.doi.org/10.1042/bst20150018.

Full text

Abstract:

Since the identification of the membrane-bound O-acyltransferase (MBOATs) protein family in the early 2000s, three distinct members [porcupine (PORCN), hedgehog (Hh) acyltransferase (HHAT) and ghrelin O-acyltransferase (GOAT)] have been shown to acylate specific proteins or peptides. In this review, topology determination, development of assays to measure enzymatic activities and discovery of small molecule inhibitors are compared and discussed for each of these enzymes.

APA, Harvard, Vancouver, ISO, and other styles

29

Zoschke, Reimo, and Alice Barkan. "Genome-wide analysis of thylakoid-bound ribosomes in maize reveals principles of cotranslational targeting to the thylakoid membrane." Proceedings of the National Academy of Sciences 112, no. 13 (March 16, 2015): E1678—E1687. http://dx.doi.org/10.1073/pnas.1424655112.

Full text

Abstract:

Chloroplast genomes encode ∼37 proteins that integrate into the thylakoid membrane. The mechanisms that target these proteins to the membrane are largely unexplored. We used ribosome profiling to provide a comprehensive, high-resolution map of ribosome positions on chloroplast mRNAs in separated membrane and soluble fractions in maize seedlings. The results show that translation invariably initiates off the thylakoid membrane and that ribosomes synthesizing a subset of membrane proteins subsequently become attached to the membrane in a nuclease-resistant fashion. The transition from soluble to membrane-attached ribosomes occurs shortly after the first transmembrane segment in the nascent peptide has emerged from the ribosome. Membrane proteins whose translation terminates before emergence of a transmembrane segment are translated in the stroma and targeted to the membrane posttranslationally. These results indicate that the first transmembrane segment generally comprises the signal that links ribosomes to thylakoid membranes for cotranslational integration. The sole exception is cytochrome f, whose cleavable N-terminal cpSecA-dependent signal sequence engages the thylakoid membrane cotranslationally. The distinct behavior of ribosomes synthesizing the inner envelope protein CemA indicates that sorting signals for the thylakoid and envelope membranes are distinguished cotranslationally. In addition, the fractionation behavior of ribosomes in polycistronic transcription units encoding both membrane and soluble proteins adds to the evidence that the removal of upstream ORFs by RNA processing is not typically required for the translation of internal genes in polycistronic chloroplast mRNAs.

APA, Harvard, Vancouver, ISO, and other styles

30

Serek-Heuberger, Justyna, Cédric F. V. Hobel, Stanislaw Dunin-Horkawicz, Beate Rockel, Jörg Martin, and Andrei N. Lupas. "Two unique membrane-bound AAA proteins from Sulfolobus solfataricus." Biochemical Society Transactions 37, no. 1 (January 20, 2009): 118–22. http://dx.doi.org/10.1042/bst0370118.

Full text

Abstract:

Thermoacidophilic crenarchaea of the genus Sulfolobus contain six AAA (ATPase associated with various cellular activities) proteins, including a proteasome-associated ATPase, a Vps4 (vacuolar protein sorting 4) homologue, and two Cdc48 (cell-division cycle 48)-like proteins. The last two AAA proteins are deeply branching divergent members of this family without close relatives outside the Sulfolobales. Both proteins have two nucleotide-binding domains and, unlike other members of the family, they seem to lack folded N-terminal domains. Instead, they contain N-terminal extensions of approx. 50 residues, which are predicted to be unstructured, except for a single transmembrane helix. We have analysed the two proteins, MBA (membrane-bound AAA) 1 and MBA2, by computational and experimental means. They appear to be monophyletic and to share a common ancestor with the Cdc48 clade. Both are membrane-bound and active as nucleotidases upon heterologous expression in Escherichia coli. They form ring complexes, which are stable after solubilization in a mild detergent and whose formation is dependent on the presence of the N-terminal extensions.

APA, Harvard, Vancouver, ISO, and other styles

31

Lüthje, Sabine, and Teresa Martinez-Cortes. "Membrane-Bound Class III Peroxidases: Unexpected Enzymes with Exciting Functions." International Journal of Molecular Sciences 19, no. 10 (September 21, 2018): 2876. http://dx.doi.org/10.3390/ijms19102876.

Full text

Abstract:

Class III peroxidases are heme-containing proteins of the secretory pathway with a high redundance and versatile functions. Many soluble peroxidases have been characterized in great detail, whereas only a few studies exist on membrane-bound isoenzymes. Membrane localization of class III peroxidases has been demonstrated for tonoplast, plasma membrane and detergent resistant membrane fractions of different plant species. In silico analysis revealed transmembrane domains for about half of the class III peroxidases that are encoded by the maize (Zea mays) genome. Similar results have been found for other species like thale-cress (Arabidopsis thaliana), barrel medic (Medicago truncatula) and rice (Oryza sativa). Besides this, soluble peroxidases interact with tonoplast and plasma membranes by protein–protein interaction. The topology, spatiotemporal organization, molecular and biological functions of membrane-bound class III peroxidases are discussed. Besides a function in membrane protection and/or membrane repair, additional functions have been supported by experimental data and phylogenetics.

APA, Harvard, Vancouver, ISO, and other styles

32

Mandala, Venkata S., Jonathan K. Williams, and Mei Hong. "Structure and Dynamics of Membrane Proteins from Solid-State NMR." Annual Review of Biophysics 47, no. 1 (May 20, 2018): 201–22. http://dx.doi.org/10.1146/annurev-biophys-070816-033712.

Full text

Abstract:

Solid-state nuclear magnetic resonance (SSNMR) spectroscopy elucidates membrane protein structures and dynamics in atomic detail to yield mechanistic insights. By interrogating membrane proteins in phospholipid bilayers that closely resemble biological membranes, SSNMR spectroscopists have revealed ion conduction mechanisms, substrate transport dynamics, and oligomeric interfaces of seven-transmembrane helix proteins. Research has also identified conformational plasticity underlying virus-cell membrane fusions by complex protein machineries, and β-sheet folding and assembly by amyloidogenic proteins bound to lipid membranes. These studies collectively show that membrane proteins exhibit extensive structural plasticity to carry out their functions. Because of the inherent dependence of NMR frequencies on molecular orientations and the sensitivity of NMR frequencies to dynamical processes on timescales from nanoseconds to seconds, SSNMR spectroscopy is ideally suited to elucidate such structural plasticity, local and global conformational dynamics, protein-lipid and protein-ligand interactions, and protonation states of polar residues. New sensitivity-enhancement techniques, resolution enhancement by ultrahigh magnetic fields, and the advent of 3D and 4D correlation NMR techniques are increasingly aiding these mechanistically important structural studies.

APA, Harvard, Vancouver, ISO, and other styles

33

Elmadhoun, Bassam M., Manal A. Swairjo, and Frank J. Burczynski. "Fluorescent Fatty Acid Transfer from Bovine Serum Albumin to Phospholipid Vesicles: Collision or Diffusion Mediated Uptake." Journal of Pharmacy & Pharmaceutical Sciences 15, no. 3 (July 19, 2012): 420. http://dx.doi.org/10.18433/j3bc8w.

Full text

Abstract:

Purpose: The extent of palmitate uptake by hepatocytes is dependent upon the surface charge of the extracellular binding protein. Specifically, hepatocyte uptake is greater when palmitate is bound to cationic binding proteins than when it is bound to anionic proteins. To further understand the role of protein surface charge on the uptake process of protein-bound ligands, we examined the rate of transfer of fluorescent anthroyloxy palmitic acid (AOPA) in the presence of anionic and cationic extracellular proteins to model membranes containing different surface charged groups. Method: AOPA transfer rate in the presence of bovine serum albumin (ALB; isoelectric point pI = 4.8-5.0) or modified ALB (ALBe; pI = 7.0-7.5) to negative, positive and neutral lipid vesicles was investigated using a fluorescence resonance energy transfer assay. Results: The rate of AOPA transfer from both proteins was decreased when ionic strength was increased; directly dependent on the concentration of acceptor lipid vesicles; and was affected by both the lipid membrane surface charge and protein-bound concentration. Conclusion: The data support the notion that AOPA transfer from binding proteins to lipid membranes occurred through two concomitant processes, aqueous diffusion of the unbound ligand (diffusion-mediated process) and a collisional interaction between the protein-ligand complex and acceptor membrane. The contribution of diffusional mediated transfer to the overall uptake process was determined to be 3 to 4 times less than the contribution of a collisional interaction. This study strengthened the hypothesis that charged amino acid residues on proteins are important for effective collisional interaction between protein-ligand complexes and cell membranes through which more free ligand could be supplied for the uptake process. This article is open to POST-PUBLICATION REVIEW. Registered readers (see “For Readers”) may comment by clicking on ABSTRACT on the issue’s contents page.

APA, Harvard, Vancouver, ISO, and other styles

34

Carmichael, Stephen W. "Very Cool Clathrin." Microscopy Today 13, no. 6 (November 2005): 3–7. http://dx.doi.org/10.1017/s1551929500053918.

Full text

Abstract:

Clathrin-coated vesicles are the shuttle containers within cells. The vesicles carry lipids and proteins between membrane-bound compartments. Clathrin forms a cage-like structure around the membrane-bound vesicle that is pinched off from the plasma membrane (in endocytosis) or a membranous component of the cytoplasm. Clathrin recruits cargo that is within a vesicle through intermediary proteins known as adaptors that help select membrane-anchored protein and form an interface between the clathrin cage and the membrane bilayer.

APA, Harvard, Vancouver, ISO, and other styles

35

Collins, P. G., and R. Gilmore. "Ribosome binding to the endoplasmic reticulum: a 180-kD protein identified by crosslinking to membrane-bound ribosomes is not required for ribosome binding activity." Journal of Cell Biology 114, no. 4 (August 15, 1991): 639–49. http://dx.doi.org/10.1083/jcb.114.4.639.

Full text

Abstract:

We have used the membrane-impermeable, thiol-cleavable, crosslinker 3,3'-dithio bis (sulfosuccinimidylpropionate) to identify proteins that are in the vicinity of membrane-bound ribosomes of the RER. A specific subset of RER proteins was reproducibly crosslinked to the ribosome. Immunoblot analysis of the crosslinked products with antibodies raised against signal recognition particle receptor, ribophorin I, and the 35-kD subunit of the signal sequence receptor demonstrated that these translocation components had been crosslinked to the ribosome, but each to a different extent. The most prominent polypeptide among the crosslinked products was a 180-kD protein that has recently been proposed to be a ribosome receptor (Savitz, A.J., and D.I. Meyer, 1990. Nature (Lond.). 346: 540-544). RER membrane proteins were reconstituted into liposomes and assayed with radiolabeled ribosomes to determine whether ribosome binding activity could be ascribed to the 180-kD protein. Differential detergent extraction was used to prepare soluble extracts of microsomal membrane vesicles that either contained or lacked the 180-kD protein. Liposomes reconstituted from both extracts bound ribosomes with essentially identical affinity. Additional fractionation experiments demonstrated that the bulk of the ribosome binding activity present in detergent extracts of microsomal membranes could be readily resolved from the 180-kD protein by size exclusion chromatography. Taken together, we conclude that the 180-kD protein is in the vicinity of membrane bound ribosomes, yet does not correspond to the ribosome receptor.

APA, Harvard, Vancouver, ISO, and other styles

36

Yoshimura, Shin-ichiro, Nobuhiro Nakamura, Francis A. Barr, Yoshio Misumi, Yukio Ikehara, Hiroshi Ohno, Masao Sakaguchi, and Katsuyoshi Mihara. "Direct targeting of cis-Golgi matrix proteins to the Golgi apparatus." Journal of Cell Science 114, no. 22 (November 15, 2001): 4105–15. http://dx.doi.org/10.1242/jcs.114.22.4105.

Full text

Abstract:

The targeting route of newly synthesized GM130 and GRASP65 to the Golgi apparatus was investigated by three different approaches. First, localization of pulse labeled GM130 and GRASP65 in normal rat kidney (NRK) cells was traced by subcellular fractionation followed by immunoprecipitation. Immediately after the pulse labeling, GM130 and GRASP65 were found in the Golgi but not in the endoplasmic reticulum (ER) membrane fractions, whereas a control Golgi membrane protein was still found in the ER membrane fractions. Second, epitope tagged GM130 and GRASP65 were expressed in NRK cells by plasmid microinjection into the nuclei and their localization was analyzed by immunofluorescence. When ER to Golgi transport was inhibited by prior microinjection of a GTP-restricted mutant of Sar1 protein into the cytosol, the expressed GM130 and GRASP65 showed clear Golgi localization. Last, binding of GM130 and GRASP65 to the membranes was analyzed in vitro. In vitro synthesized GM130 and GRASP65 specifically bound to purified Golgi membranes but not to microsomal membranes. The bound GM130 and GRASP65 were found to form a complex with pre-existing counterparts on the Golgi membrane. These results strongly suggested that GM130 and GRASP65 are directly targeted to the Golgi membrane without initial assembly on the ER and subsequent vesicular transport to the Golgi apparatus.

APA, Harvard, Vancouver, ISO, and other styles

37

Donaldson, Julie G. "Arfs and membrane lipids: sensing, generating and responding to membrane curvature." Biochemical Journal 414, no. 2 (August 12, 2008): e1-e2. http://dx.doi.org/10.1042/bj20081438.

Full text

Abstract:

Arf family GTP-binding proteins function in the regulation of membrane-trafficking events and in the maintenance of organelle structure. They act at membrane surfaces to modify lipid composition and to recruit coat proteins for the generation of transport vesicles. Arfs associate with membranes through insertion of an N-terminal myristoyl moiety in conjunction with an adjacent amphipathic α-helix, which embeds in the lipid bilayer when Arf1 is GTP-bound. In this issue of the Biochemical Journal, Lundmark et al. report that myristoylated Arfs in the presence of GTP bind to and cause tubulation of liposomes, and that GTP exchange on to Arfs is more efficient in the presence of liposomes of smaller diameter (increased curvature). These findings suggest that Arf protein activation and membrane interaction may initiate membrane curvature that will be enhanced further by coat proteins during vesicle formation.

APA, Harvard, Vancouver, ISO, and other styles

38

Jun, Hyun-Sik, Meng Qi, Joshua Gong, Emmanuel E. Egbosimba, and Cecil W. Forsberg. "Outer Membrane Proteins of Fibrobacter succinogenes with Potential Roles in Adhesion to Cellulose and in Cellulose Digestion." Journal of Bacteriology 189, no. 19 (July 20, 2007): 6806–15. http://dx.doi.org/10.1128/jb.00560-07.

Full text

Abstract:

ABSTRACT Comparative analysis of binding of intact glucose-grown Fibrobacter succinogenes strain S85 cells and adhesion-defective mutants AD1 and AD4 to crystalline and acid-swollen (amorphous) cellulose showed that strain S85 bound efficiently to both forms of cellulose while mutant Ad1 bound to acid-swollen cellulose, but not to crystalline cellulose, and mutant Ad4 did not bind to either. One- and two-dimensional electrophoresis (2-DE) of outer membrane cellulose binding proteins and of outer membranes, respectively, of strain S85 and adhesion-defective mutant strains in conjunction with mass spectrometry analysis of tryptic peptides was used to identify proteins with roles in adhesion to and digestion of cellulose. Examination of the binding to cellulose of detergent-solubilized outer membrane proteins from S85 and mutant strains revealed six proteins in S85 that bound to crystalline cellulose that were absent from the mutants and five proteins in Ad1 that bound to acid-swollen cellulose that were absent from Ad4. Twenty-five proteins from the outer membrane fraction of cellulose-grown F. succinogenes were identified by 2-DE, and 16 of these were up-regulated by growth on cellulose compared to results with growth on glucose. A protein identified as a Cl-stimulated cellobiosidase was repressed in S85 cells growing on glucose and further repressed in the mutants, while a cellulose-binding protein identified as pilin was unchanged in S85 grown on glucose but was not produced by the mutants. The candidate differential cellulose binding proteins of S85 and the mutants and the proteins induced by growth of S85 on cellulose provide the basis for dissecting essential components of the cellulase system of F. succinogenes.

APA, Harvard, Vancouver, ISO, and other styles

39

Wheeler, Richard J., and Anthony A. Hyman. "Controlling compartmentalization by non-membrane-bound organelles." Philosophical Transactions of the Royal Society B: Biological Sciences 373, no. 1747 (April 9, 2018): 20170193. http://dx.doi.org/10.1098/rstb.2017.0193.

Full text

Abstract:

Compartmentalization is a characterizing feature of complexity in cells, used to organize their biochemistry. Membrane-bound organelles are most widely known, but non-membrane-bound liquid organelles also exist. These have recently been shown to form by phase separation of specific types of proteins known as scaffolds. This forms two phases: a condensate that is enriched in scaffold protein separated by a phase boundary from the cytoplasm or nucleoplasm with a low concentration of the scaffold protein. Phase separation is well known for synthetic polymers, but also appears important in cells. Here, we review the properties of proteins important for forming these non-membrane-bound organelles, focusing on the energetically favourable interactions that drive condensation. On this basis we make qualitative predictions about how cells may control compartmentalization by condensates; the partition of specific molecules to a condensate; the control of condensation and dissolution of condensates; and the regulation of condensate nucleation. There are emerging data supporting many of these predictions, although future results may prove incorrect. It appears that many molecules may have the ability to modulate condensate formation, making condensates a potential target for future therapeutics. The emerging properties of condensates are fundamentally unlike the properties of membrane-bound organelles. They have the capacity to rapidly integrate cellular events and act as a new class of sensors for internal and external environments. This article is part of the theme issue ‘Self-organization in cell biology’.

APA, Harvard, Vancouver, ISO, and other styles

40

Church, Jon G., Shobha Ghosh, Basil D. Roufogalis, and Antonio Villalobo. "Endogenous hyperphosphorylation in plasma membrane from an ascites hepatocarcinoma cell line." Biochemistry and Cell Biology 66, no. 1 (January 1, 1988): 1–12. http://dx.doi.org/10.1139/o88-001.

Full text

Abstract:

Plasma-membrane-bound kinases of AS-30D ascites from transplantable rat hepatocarcinoma were shown to extensively catalyze the phosphorylation of plasma membrane proteins and membrane lipids, using [γ-32P]ATP or [γ-32P]GTP as a phosphate donor. In contrast, plasma membranes from normal adult rat liver or fast-growing regenerating liver (24 h after partial hepatectomy) produce significantly less activity for protein phosphorylation and little phosphorylation of the lipids. However, neonatal (24 h old) rat liver plasma membrane preparations show levels of phosphorylation of proteins and lipids intermediate between those in the tumor cell line and normal adult plasma membrane preparations. Phosphatidic acid was identified as one of the 32P-labelled lipids in the tumor plasma membrane chloroform–methanol (2:1, v/v) extract. Phosphorylation of protein was not affected by cAMP or cGMP. However, calcium ion (in the presence or absence of calmodulin) significantly modifies the 32P labelling of a series of proteins in normal tissue but has little effect with the neoplastic preparations. Some plasma membrane proteins were capable of nucleotide binding, instead or in addition to being phosphorylated. Finally, the presence of membrane-bound phosphoprotein phosphatase(s) was also demonstrated in all the preparations examined by means of chase experiments with nonlabelled ATP or GTP, and (or) by the use of the phosphoprotein phosphatase inhibitor, orthovanadate.

APA, Harvard, Vancouver, ISO, and other styles

41

Matos, Anna Lívia Linard, Sergej Kudruk, Johanna Moratz, Milena Heflik, David Grill, Bart Jan Ravoo, and Volker Gerke. "Membrane Binding Promotes Annexin A2 Oligomerization." Cells 9, no. 5 (May 8, 2020): 1169. http://dx.doi.org/10.3390/cells9051169.

Full text

Abstract:

Annexin A2 (AnxA2) is a cytosolic Ca2+ regulated membrane binding protein that can induce lipid domain formation and plays a role in exocytosis and endocytosis. To better understand the mode of annexin-membrane interaction, we analyzed membrane-bound AnxA2 assemblies by employing a novel 3-armed chemical crosslinker and specific AnxA2 mutant proteins. Our data show that AnxA2 forms crosslinkable oligomers upon binding to membranes containing negatively charged phospholipids. AnxA2 mutants with amino acid substitutions in residues predicted to be involved in lateral protein–protein interaction show compromised oligomer formation, albeit still being capable of binding to negatively charged membranes in the presence of Ca2+. These results suggest that lateral protein–protein interactions are involved in the formation of AnxA2 clusters on a biological membrane.

APA, Harvard, Vancouver, ISO, and other styles

42

El-Hage, Nazira, and Guangxiang Luo. "Replication of hepatitis C virus RNA occurs in a membrane-bound replication complex containing nonstructural viral proteins and RNA." Journal of General Virology 84, no. 10 (October 1, 2003): 2761–69. http://dx.doi.org/10.1099/vir.0.19305-0.

Full text

Abstract:

Biochemical studies revealed that nonstructural proteins of hepatitis C virus (HCV) interacted with each other and were associated with intracellular membranes. The goals of this study were to determine whether nonstructural viral proteins are colocalized at specific intracellular sites where HCV RNA is replicated and to identify the virus components of the HCV replication complex (RC). Immunofluorescence and subcellular fractionation studies were performed to determine the intracellular colocalization of nonstructural HCV proteins and the replicating RNA in a human hepatoma cell line, Huh7, in which a subgenomic HCV RNA was replicated persistently. The replicating HCV RNA was labelled with 5-bromouridine 5′-triphosphate (BrUTP). Results show that each of the nonstructural HCV proteins was colocalized predominantly with the newly synthesized HCV RNA labelled with BrUTP and an endoplasmic reticulum (ER) protein, calnexin. Consistent with these findings, subcellular fractionation and Western blot analyses revealed that the nonstructural HCV proteins were colocalized with HCV RNA mainly in the membrane fractions. Conversely, the viral nonstructural proteins and RNA remained in the soluble fractions upon treatment with detergent, confirming the membrane association of the HCV RC. HCV RNA in the membrane-bound RC was resistant to RNase treatment, whereas it became sensitive to RNases once the membranes were disrupted by treatment with detergent, suggesting that the HCV RC is assembled within membrane structures. Collectively, these findings demonstrate that HCV RNA replication occurs in the perinuclear ER membrane-bound HCV RC, containing nonstructural viral proteins and RNA.

APA, Harvard, Vancouver, ISO, and other styles

43

Vidilaseris, Keni, Juho Kellosalo, and Adrian Goldman. "A high-throughput method for orthophosphate determination of thermostable membrane-bound pyrophosphatase activity." Analytical Methods 10, no. 6 (2018): 646–51. http://dx.doi.org/10.1039/c7ay02558k.

Full text

Abstract:

Membrane-bound pyrophosphatases (mPPases) are homodimeric integral membrane proteins that hydrolyse pyrophosphate into orthophosphates coupled to the active transport of protons or sodium ions across membranes.

APA, Harvard, Vancouver, ISO, and other styles

44

Seidler, A., K. Jaschkowitz, and M. Wollenberg. "Incorporation of iron-sulphur clusters in membrane-bound proteins." Biochemical Society Transactions 29, no. 4 (August 1, 2001): 418–21. http://dx.doi.org/10.1042/bst0290418.

Full text

Abstract:

The completely sequenced genome of the cyano-bacterium Synechocystis PCC 6803 contains several open reading frames, of which the deduced amino acid sequences show similarities to proteins known to be involved in FeS cluster synthesis of nitrogenase (Nif proteins) and other FeS proteins (Isc proteins). In this article, the results of our studies on these proteins are summarized and discussed with respect to their relevance in FeS cluster incorporation in chloroplasts. In cyanobacteria, there appears to exist several pathways for FeS cluster synthesis.

APA, Harvard, Vancouver, ISO, and other styles

45

Reynolds, A. M. "On the anomalous diffusion characteristics of membrane-bound proteins." Physics Letters A 342, no. 5-6 (July 2005): 439–42. http://dx.doi.org/10.1016/j.physleta.2005.05.086.

Full text

APA, Harvard, Vancouver, ISO, and other styles

46

Westermann, Martin, Christian Hoischen, Jörg Müller, and Walter Richter. "Freeze-fracture Immunolabelling of Cytoplasmatic not Membrane-bound Proteins." Microscopy and Microanalysis 9, S03 (September 2003): 420–21. http://dx.doi.org/10.1017/s1431927603034184.

Full text

APA, Harvard, Vancouver, ISO, and other styles

47

Chen, Chiu-Hao, Šárka Málková, Wonhwa Cho, and Mark L. Schlossman. "Configuration of membrane-bound proteins by x-ray reflectivity." Journal of Applied Physics 110, no. 10 (November 15, 2011): 102215. http://dx.doi.org/10.1063/1.3661985.

Full text

APA, Harvard, Vancouver, ISO, and other styles

48

Carton, Ixaskun, Alain R. Brisson, and Ralf P. Richter. "Label-Free Detection of Clustering of Membrane-Bound Proteins." Analytical Chemistry 82, no. 22 (November 15, 2010): 9275–81. http://dx.doi.org/10.1021/ac102495q.

Full text

APA, Harvard, Vancouver, ISO, and other styles

49

Scarlata, S. "The effect of hydrostatic pressure on membrane-bound proteins." Brazilian Journal of Medical and Biological Research 38, no. 8 (August 2005): 1203–8. http://dx.doi.org/10.1590/s0100-879x2005000800007.

Full text

APA, Harvard, Vancouver, ISO, and other styles

50

Seidler, A., K. Jaschkowitz, and M. Wollenberg. "Incorporation of iron-sulphur clusters into membrane-bound proteins." Biochemical Society Transactions 29, no. 3 (June 1, 2001): A51. http://dx.doi.org/10.1042/bst029a051a.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Membrane bound proteins'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles