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Journal articles on the topic 'Plasma membrane'
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1
Ahmed, Sadiq, and Andre Kaplan. "Therapeutic Plasma Exchange Using Membrane Plasma Separation." Clinical Journal of the American Society of Nephrology 15, no. 9 (April 20, 2020): 1364–70. http://dx.doi.org/10.2215/cjn.12501019.
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Therapeutic plasma exchange is a blood purification technique designed for the removal of large molecular weight toxins such as pathogenic antibodies and lipoproteins. Plasma exchange can be performed either by membrane separation or centrifugation. Centrifugal plasma exchange is more common in the United States, while membrane separation is more popular in Germany and Japan. The membrane separation technique is similar to the ultrafiltration procedures performed with a standard dialysis machine but in which the membrane’s pores are large enough to allow removal of all circulating molecules while retaining the cellular components. The current availability of plasma separation membranes compatible with CRRT systems has dramatically increased the potential for almost all nephrologists to perform these treatments. This review describes the membrane separation techniques available in the United States, the practical aspects of ordering and operating a membrane separation plasma exchange procedure, and its possible complications.
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Bakouche, O., Y. Ichinose, R. Heicappell, I. J. Fidler, and L. B. Lachman. "Plasma membrane-associated tumor necrosis factor. A non-integral membrane protein possibly bound to its own receptor." Journal of Immunology 140, no. 4 (February 15, 1988): 1142–47. http://dx.doi.org/10.4049/jimmunol.140.4.1142.
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Abstract Purified plasma membranes from LPS-activated human blood monocytes produced significant lysis and growth inhibition of the TNF-sensitive L929 murine fibroblast cell line. Unactivated human monocyte plasma membranes did not display either activity. Anti-TNF serum specifically inhibited the anti-tumor activity of activated monocyte membranes whereas anti-IL-1 serum or non-specific rabbit serum decreased neither the lysis nor growth inhibition of L929 cells. Membrane-associated TNF did not behave as an integral protein as it could be eluted from the plasma membranes by either high salt or low pH treatment. Plasma membranes cleared of membrane-associated TNF by high salt treatment were able to bind TNF, and this binding was specifically inhibited by preincubation of rTNF with specific anti-TNF serum. Western blot analysis of plasma membranes showed a membrane-associated TNF with a m. w. of approximately 17 kDa present only in the activated monocytes. When the plasma membranes were preincubated with the cross-linker agent dissuccinimidyl suberate, Western blot analysis revealed the presence of a TNF-binding protein with a Mr of approximately 102 kDa. These studies indicate that unlike IL-1, membrane-associated TNF is not an integral membrane protein and that TNF may be associated with the monocyte membrane by occupying the TNF R.
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Matthes, Bernd, and Peter Böger. "Chloroacetamides Affect the Plasma Membrane." Zeitschrift für Naturforschung C 57, no. 9-10 (October 1, 2002): 843–52. http://dx.doi.org/10.1515/znc-2002-9-1015.
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In the present study membrane fatty acids were analyzed to find a link between the biosynthesis inhibition of very-long-chain fatty acids and the phytotoxic effects of herbicidal chloroacetamides. Accordingly,we have isolated membranes of cucumber seedlings (Cucumis sativus) by two-phase partitioning and analyzed their fatty acid content. Saturated VLCFAs ranging from C20 to C26 were found in high amounts (22%) in the plasma membrane fraction. Nonmodified VLCFAs were predominantly present in phospholipids, while saturated 2-hydroxylated VLCFAs were identified in cerebrosides. Treatment of intact seedlings with chloroacetamides markedly reduced the VLCFA content in the plasma membrane. This result could be specified by fatty-acid labeling using [14C]malonate as a substrate for fatty acid elongation. De novo incorporation of VLCFAs into the plasma membrane and into microsomal membranes, respectively, was severely impaired by chloroacetamides with I50 values between 10 to 100 nm. These results confirm the previous finding that chloroacetamides inhibit VLCFA biosynthesis localized in the microsomes (Böger et al., Pest Manage. Sci. 56, 497D508, 2000). The direct consequence of this inhibition is a strong decrease of VLCFAs required as constituents of the plasma membrane and the substitution by shorter acyl chains. Apparently, physical properties and function of the plasma membrane are affected eventually leading to death of the plant.
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Taylor, C. W., and O. Dellis. "Plasma membrane IP3 receptors." Biochemical Society Transactions 34, no. 5 (October 1, 2006): 910–12. http://dx.doi.org/10.1042/bst0340910.
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IP3Rs (inositol 1,4,5-trisphosphate receptors) are expressed in the membranes of non-mitochondrial organelles in most animal cells, but their presence and role within the plasma membrane are unclear. Whole-cell patch–clamp recording from DT40 cells expressing native or mutated IP3Rs has established that each cell expresses just two or three functional IP3Rs in its plasma membrane. Only approx. 50% of the Ca2+ entry evoked by stimulation of the B-cell receptor is mediated by store-operated Ca2+ entry, the remainder appears to be carried by the IP3Rs expressed in the plasma membrane. Ca2+ entering the cell via just two large-conductance IP3Rs is likely to have very different functional consequences from the comparable amount of Ca2+ that enters through the several thousand low-conductance store-operated channels.
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Beaulieu, Nadine, Bari Zahedi, Rebecca E. Goulding, Ghazaleh Tazmini, Kira V. Anthony, Stephanie L. Omeis, Danielle R. de Jong, and Robert J. Kay. "Regulation of RasGRP1 by B Cell Antigen Receptor Requires Cooperativity between Three Domains Controlling Translocation to the Plasma Membrane." Molecular Biology of the Cell 18, no. 8 (August 2007): 3156–68. http://dx.doi.org/10.1091/mbc.e06-10-0932.
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RasGRP1 is a Ras-activating exchange factor that is positively regulated by translocation to membranes. RasGRP1 contains a diacylglycerol-binding C1 domain, and it has been assumed that this domain is entirely responsible for RasGRP1 translocation. We found that the C1 domain can contribute to plasma membrane-targeted translocation of RasGRP1 induced by ligation of the B cell antigen receptor (BCR). However, this reflects cooperativity of the C1 domain with the previously unrecognized Plasma membrane Targeter (PT) domain, which is sufficient and essential for plasma membrane targeting of RasGRP1. The adjacent suppressor of PT (SuPT) domain attenuates the plasma membrane-targeting activity of the PT domain, thus preventing constitutive plasma membrane localization of RasGRP1. By binding to diacylglycerol generated by BCR-coupled phospholipase Cγ2, the C1 domain counteracts the SuPT domain and enables efficient RasGRP1 translocation to the plasma membrane. In fibroblasts, the PT domain is inactive as a plasma membrane targeter, and the C1 domain specifies constitutive targeting of RasGRP1 to internal membranes where it can be activated and trigger oncogenic transformation. Selective use of the C1, PT, and SuPT domains may contribute to the differential targeting of RasGRP1 to the plasma membrane versus internal membranes, which has been observed in lymphocytes and other cell types.
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Teiwes, Nikolas K., Ingo Mey, Phila C. Baumann, Lena Strieker, Ulla Unkelbach, and Claudia Steinem. "Pore-Spanning Plasma Membranes Derived from Giant Plasma Membrane Vesicles." ACS Applied Materials & Interfaces 13, no. 22 (May 27, 2021): 25805–12. http://dx.doi.org/10.1021/acsami.1c06404.
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Roth, J., M. J. Lentze, and E. G. Berger. "Immunocytochemical demonstration of ecto-galactosyltransferase in absorptive intestinal cells." Journal of Cell Biology 100, no. 1 (January 1, 1985): 118–25. http://dx.doi.org/10.1083/jcb.100.1.118.
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Galactosyltransferase immunoreactive sites were localized in human duodenal enterocytes by the protein A-gold technique on thin sections from low temperature Lowicryl K4M embedded biopsy specimens. Antigenic sites detected with affinity-purified, monospecific antibodies were found at the plasma membrane of absorptive enterocytes with the most intense labeling appearing along the brush border membrane. The lateral plasma membrane exhibited a lower degree of labeling at the level of the junctional complexes but the membrane interdigitations were intensely labeled. The labeling intensity decreased progressively towards the basal part of the enterocytes and reached the lowest degree along the basal plasma membrane. Quantitative evaluation of the distribution of gold-particle label proved its preferential orientation to the outer surface of the plasma membrane. In addition to this membrane-associated labeling, the glycocalyx extending from the microvillus tips was heavily labeled. Occasionally, cells without plasma membrane labeling were found adjacent to positive cells. The demonstration of ecto-galactosyltransferase on membranes other than Golgi membranes precludes its general use as a marker for Golgi membrane fractions. The possible function of galactosyltransferase on a luminal plasma membrane is unclear at present, but a role in adhesion appears possible on the basolateral plasma membrane.
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Ji, Zuohui, Yue Zhao, Min Zhang, Xiaopeng Li, and Heguo Li. "Surface Modification of ETFE Membrane and PTFE Membrane by Atmospheric DBD Plasma." Membranes 12, no. 5 (May 10, 2022): 510. http://dx.doi.org/10.3390/membranes12050510.
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Fluorine resin membranes with excellent chemical resistance have great potential for the application of high-performance chemical protective clothing. However, it is difficult to integrate fluorine resins into other materials such as fabrics due to their lower surface energy and poor bondability, making the fabrication of composite fabrics and the further seal splicing challenging. In this study, atmospheric pressure dielectric barrier discharge (DBD) plasma in helium (He) and helium/acrylic acid (He/AA) mixture atmospheres were used to modify two kinds of fluorine resins, ethylene tetrafluoroethylene (ETFE) and polytetrafluoroethylene (PTFE) membrane. The surface chemical properties, physical morphology, hydrophilicity and adhesion strength of the fluororesin membranes before and after plasma treatments were systematically analyzed. The results showed that the plasma treatment can modify the membrane surface at the nanoscale level without damaging the main body of the membrane. The hydrophilicity of the plasma-treated membrane was improved with the water contact angle decreasing from 95.83° to 49.9° for the ETFE membrane and from 109.9° to 67.8° for the PTFE membrane, respectively. The He plasma creates active sites on the membrane surface as well as etching the membrane surface, increasing the surface roughness. The He/AA plasma treatment introduces two types of polyacrylic acid (PAA)—deposited polyacrylic acid (d-PAA) and grafted polyacrylic acid (g-PAA)—on the membrane surface. Even after ultrasonic washing with acetone, g-PAA still existed stably and, as a result, improved the polarity and adhesion strength of fluororesin membranes. This work provides useful insights into the modification mechanism of DBD plasma on fluorine resins, with implications for developing effective strategies of integrating fluorine resin membrane to chemical protective clothing fabrics.
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Kwan, Chiu-Yin. "Aggregation of smooth muscle membranes and its use in the preparation of plasma membrane enriched fraction from gastric fundus smooth muscle." Biochemistry and Cell Biology 64, no. 6 (June 1, 1986): 535–42. http://dx.doi.org/10.1139/o86-075.
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Microsomal membranes isolated from rat gastric fundus smooth muscle by differential centrifugation aggregate substantially in the presence of the divalent metal ion Mg2+ or Ca2+. The magnitude of cation-induced membrane aggregation is higher for Ca2+ than for Mg2+, but the ion concentration required for half-maximum membrane aggregation (K0.5 value) is similar for Mg2+ and Ca2+. Cation-induced membrane aggregation is suppressed by high ionic strength and low pH of the medium. Cation-induced membrane aggregation of mitochondrial membrane and plasma membrane enriched fractions differ in the rate of aggregate formation, metal ion concentration dependence, and pH dependence. Such different properties of membrane aggregation were used to prepare a plasma membrane enriched fraction by conventional differential centrifugation. Subfractionation of the heterogenous microsomal membranes by free-flow electrophoresis indicated that smooth muscle plasma membranes showed a higher electrophoretic mobility than the intracellular membranes. These results suggest that ionic interactions on the cell membrane surfaces differ from those on the intracellular membrane surfaces and that induction of membrane aggregation by Ca2+ or Mg2+ is a useful procedure for an effective and rapid preparation of plasma membrane enriched fraction from smooth muscle.
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Block, E. R., J. M. Patel, and D. Edwards. "Mechanism of hypoxic injury to pulmonary artery endothelial cell plasma membranes." American Journal of Physiology-Cell Physiology 257, no. 2 (August 1, 1989): C223—C231. http://dx.doi.org/10.1152/ajpcell.1989.257.2.c223.
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We exposed monolayer cultures of pulmonary artery endothelial cells or plasma membranes derived from these cells to hypoxic (0 and 5% O2) and normoxic (20% O2; control) conditions and measured cellular contents of malondialdehyde and conjugated dienes, plasma membrane fluidity and lipid composition, and plasma membrane-dependent transport of 5-hydroxytryptamine (5-HT). Hypoxia caused significant increases in malondialdehyde and conjugated dienes, in fluidity, and in 5-HT transport. Hypoxia also caused a significant decrease in plasma membrane total phospholipids and a marked increase in plasma membrane free fatty acids that appeared to be due to release of fatty acids from the plasma membrane phospholipids. The increases in fluidity and 5-HT transport and the alterations in fatty acids were reversible after return to control conditions. These results indicate that hypoxia alters the physical state, lipid composition, and function of endothelial cell plasma membranes by a combination of stimulation of membrane lipid peroxidation and accelerated degradation of membrane phospholipids, the latter probably secondary to activation of membrane phospholipases.
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Molday, R. S., and L. L. Molday. "Differences in the protein composition of bovine retinal rod outer segment disk and plasma membranes isolated by a ricin-gold-dextran density perturbation method." Journal of Cell Biology 105, no. 6 (December 1, 1987): 2589–601. http://dx.doi.org/10.1083/jcb.105.6.2589.
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The plasma membrane and disk membranes of bovine retinal rod outer segments (ROS) have been purified by a novel density-gradient perturbation method for analysis of their protein compositions. Purified ROS were treated with neuraminidase to expose galactose residues on plasma membrane-specific glycoproteins and labeled with ricin-gold-dextran particles. After the ROS were lysed in hypotonic buffer, the plasma membrane was dissociated from the disks by either mild trypsin digestion or prolonged exposure to low ionic strength buffer. The dense ricin-gold-dextran-labeled plasma membrane was separated from disks by sucrose gradient centrifugation. Electron microscopy was used to follow this fractionation procedure. The dense red pellet primarily consisted of inverted plasma membrane vesicles containing gold particles; the membrane fraction of density 1.13 g/cc consisted of unlabeled intact disks and vesicles. Ricin-binding studies indicated that the plasma membrane from trypsin-treated ROS was purified between 10-15-fold. The protein composition of plasma membranes and disks was significantly different as analyzed by SDS gels and Western blots labeled with lectins and monoclonal antibodies. ROS plasma membrane exhibited three major proteins of 36 (rhodopsin), 38, and 52 kD, three ricin-binding glycoproteins of 230, 160, and 110 kD, and numerous minor proteins in the range of 14-270 kD. In disk membranes rhodopsin appeared as the only major protein. A 220-kD concanavalin A-binding glycoprotein and peripherin, a rim-specific protein, were also present along with minor proteins of 43 and 57-63 kD. Radioimmune assays indicated that the ROS plasma membrane contained about half as much rhodopsin as disk membranes.
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Ali, N., R. Aligue, and W. H. Evans. "Highly purified bile-canalicular vesicles and lateral plasma membranes isolated from rat liver on Nycodenz gradients. Biochemical and immunolocalization studies." Biochemical Journal 271, no. 1 (October 1, 1990): 185–92. http://dx.doi.org/10.1042/bj2710185.
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1. A liver canalicular plasma-membrane fraction enriched 115-155-fold in five marker enzymes relative to the tissue homogenate was obtained by sonication of liver plasma membranes followed by fractionation in iso-osmotic Nycodenz gradients. 2. Two lateral-plasma membrane fractions were also collected by this procedure; the lighter-density fraction was still associated with canalicular membranes, as assessed by enzymic and polypeptide analysis. 3. The polypeptide composition of the domain-defined plasma-membrane fractions was evaluated. It was demonstrated by immunoblotting that the 41 kDa alpha-subunit of the inhibitory G-protein, associated in high relative amounts with canalicular plasma-membrane fractions, was partially lost in the last stage of purification; however, this subunit was retained by lateral plasma membranes. 4. Antibodies to the proteins of bile-canalicular vesicles were shown to localize to the hepatocyte surface in thin liver sections examined by immunofluorescent and immuno-gold electron microscopy. Two subsets of antigens were identified, one present on both sinusoidal and canalicular plasma-membrane domains and another, by using antisera pre-absorbed with sinusoidal plasma membranes, that was confined to the bile-canalicular domain.
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Suzuki, Jun, and Shigekazu Nagata. "Phospholipid Scrambling on Plasma Membrane." MEMBRANE 37, no. 4 (2012): 174–78. http://dx.doi.org/10.5360/membrane.37.174.
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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.
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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.
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Scott, Haden L., Kristen B. Kennison, Thais A. Enoki, Milka Doktorova, Jacob J. Kinnun, Frederick A. Heberle, and John Katsaras. "Model Membrane Systems Used to Study Plasma Membrane Lipid Asymmetry." Symmetry 13, no. 8 (July 26, 2021): 1356. http://dx.doi.org/10.3390/sym13081356.
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It is well known that the lipid distribution in the bilayer leaflets of mammalian plasma membranes (PMs) is not symmetric. Despite this, model membrane studies have largely relied on chemically symmetric model membranes for the study of lipid–lipid and lipid–protein interactions. This is primarily due to the difficulty in preparing stable, asymmetric model membranes that are amenable to biophysical studies. However, in the last 20 years, efforts have been made in producing more biologically faithful model membranes. Here, we review several recently developed experimental and computational techniques for the robust generation of asymmetric model membranes and highlight a new and particularly promising technique to study membrane asymmetry.
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Maeda, Manabu, Yasuo Kitajima, Yukiko Shikano, and Shunji Mori. "Freeze-fracture electron microscopic studies of age-related plasma membrane changes in Sporothrix schenckii." Canadian Journal of Microbiology 33, no. 1 (January 1, 1987): 40–47. http://dx.doi.org/10.1139/m87-007.
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Characteristics of the plasma membrane of Sporothrix scheckii cells as revealed by freeze-fracture techniques have been classified into eight types (Y1, Y2a, Y2b, Y3a, Y3b, Y4a, Y4b, and Y5) in yeastlike cells grown under the following two conditions: brain heart infusion agar medium at 27 °C, and brain heart infusion agar medium at 37 °C. Type Y1 cells are yeastlike cells having smooth plasma membranes without any invagination. Typical characteristics of the other types are as follows: type Y2a, smooth plasma membranes with few trenchlike invaginations; type Y2b, wavy plasma membranes with few oval or irregularly formed invaginations; type Y3a, plasma membranes with many randomly distributed trenchlike invaginations; type Y3b, plasma membranes with many cocoonlike or irregularly formed invaginations; type Y4a, plasma membranes with longer trenchlike invaginations; type Y4b, plasma membranes with irregularly formed, enlarged invaginations; and type Y5, smooth or wavy plasma membranes with aggregations of intramembranous particles and with many vacuoles between cell walls and plasma membranes or in the cytoplasm in some cells. By counting the proportion of each type of yeastlike cell under the two conditions and with different cultivation periods, it appears that plasma membrane types change as aging progresses in the following order: type Y1, Y2a, Y3a, Y4a, and Y5 in conidia and type Y1, Y2b, Y3b, Y4b, and Y5 in yeastlike vegetative cells. These observations provide us with an important advantage when studying the effects of antifungal agents on the plasma membrane of Sporothrix scheckii, as it is important to know the natural course of changes in membrane structure during aging.
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MacLean, C. M., and J. M. Edwardson. "Fusion between rat pancreatic zymogen granules and plasma membranes. Modulation by a GTP-binding protein." Biochemical Journal 286, no. 3 (September 15, 1992): 747–53. http://dx.doi.org/10.1042/bj2860747.
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At the moment, little is known about the molecular characteristics of the final step in the process of regulated exocytosis, i.e. the fusion of the membrane of a secretory vesicle with the plasma membrane. We have reconstituted this fusion event in vitro, using zymogen granules and plasma membranes from the exocrine pancreas of the rat. The membranes of zymogen granules were loaded with the lipid-soluble fluorescent probe octadecylrhodamine B, at a concentration that resulted in self-quenching of its fluorescence. The granules were then incubated with pancreatic plasma membranes at 37 degrees C, and fusion was measured through the dilution-dependent de-quenching of the fluorescence of the probe. Zymogen granules fused with pancreatic plasma membranes, but not with plasma membranes from liver or chromaffin cells; granules also fused with unlabelled granule membranes. The fusion of granules with plasma membranes was unaffected by variation of the Ca2+ concentration over a wide range, but fusion of granules with both plasma membranes and zymogen granule membranes was stimulated by GTP and, more potently, by guanosine 5′-[gamma-thio]triphosphate (GTP[S]). The effect of GTP[S] was to increase the extent of fusion occurring at low concentrations of plasma membranes, without affecting the maximum signal obtained at high membrane concentrations. Pre-incubation of the plasma membranes with GTP[S] also enhanced their ability to fuse with zymogen granules. Our results indicate that membrane fusion during exocytosis may be under the direct control of a GTP-binding protein.
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Maliszewska, Irena, and Tomasz Czapka. "Biofouling Removal from Membranes Using Nonthermal Plasma." Energies 13, no. 17 (August 20, 2020): 4318. http://dx.doi.org/10.3390/en13174318.
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An essential aspect of wastewater treatment systems based on membranes is fouling, which leads to a decrease in their performance and durability. The membrane biofouling is directly related to the deposition of biological particles (e.g., microorganisms in the form of biofilm) on the membrane surface. The objective of the study was to investigate the possibility of using nonthermal plasma for membrane treatment to overcome the biofouling problem. The removal of biological cells from the membrane surface was performed in a dielectric barrier discharge (DBD) plasma. The biofoulant (i.e., activated sludge) on the surface of membranes was treated with plasma for 3–10 min, corresponding to a plasma dose of 13–42 J cm−2. Results of biofouling removal studies indicated that the process was very efficient (i.e., lethal effect was also observed) and dependent on the type of membrane and exposure time to the nonthermal plasma. Moreover, investigations of the influence of plasma treatment on extracellular polymeric substances of biofilms have confirmed the possibility of using plasma in the process of protein release from biological structures, which results in their destruction. It seems that plasma technologies can be part of the so-called hybrid methods of removing biological contamination of membranes used in wastewater treatment.
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Nadin, C. Y., J. Rogers, S. Tomlinson, and J. M. Edwardson. "A specific interaction in vitro between pancreatic zymogen granules and plasma membranes: stimulation by G-protein activators but not by Ca2+." Journal of Cell Biology 109, no. 6 (December 1, 1989): 2801–8. http://dx.doi.org/10.1083/jcb.109.6.2801.
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The molecular details of the final step in the process of regulated exocytosis, the fusion of the membrane of the secretory granule with the plasma membrane, are at present obscure. As a first step in an investigation of this membrane fusion event, we have developed a cell-free assay for the interaction between pancreatic zymogen granules and plasma membranes. We show here that plasma membranes are able to trigger the release of the granule contents, and that this effect is specific to pancreatic membranes, involves membrane fusion, requires membrane proteins, and is stimulated by activators of G-proteins but not by Ca2+. The assay is simple, reliable, and rapid, and should permit the identification of proteins that are involved in the exocytotic fusion event.
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Cui, Y., KA Harvey, RA Siddiqui, J. Jansen, LP Akard, JM Thompson, JG Garcia, and D. English. "Cytosolic inactivation of translocated neutrophil plasma membrane protein tyrosine phosphatase." Blood 87, no. 1 (January 1, 1996): 341–49. http://dx.doi.org/10.1182/blood.v87.1.341.341.
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Abstract Phosphotyrosine phosphatases (PTPases) regulate cellular metabolic activation by reversing the effects of tyrosine kinases activated earlier in intracellular signaling pathways. We coupled fluorescence-activated cell sorter analysis using anti-CD45 monoclonal antibody with direct measurements of enzyme activity in resolved subcellular fractions to define mechanisms that potentially regulate the availability and activity of CD45-PTPase on neutrophil plasma membranes. Neutrophils in freshly obtained blood as well as neutrophils freshly isolated from blood were found to possess detectable levels of plasma membrane CD45 as assessed by immunofluorescence. However, plasma membranes from these cells were essentially devoid of PTPase catalytic activity, which was largely confined to the specific granules. Granulocyte-macrophage colony-stimulating factor (GM-CSF) upregulated both the catalytic and antigenic components of CD45-PTPase on the plasma membrane of these cells. Upregulation was associated with a shift in the particulate subcellular PTPase catalytic activity from the specific granule fraction to the plasma membrane fraction. The tyrosine kinase inhibitor genistein abrogated GM-CSF-promoted upregulation of plasma membrane CD45 PTPase but did not prevent the GM-CSF-dependent decrease in specific granule catalytic activity. Anti-CD45 antibody immunoprecipitated PTPase activity from both specific granules of resting cells and plasma membranes of GM-CSF-treated cells. However, antiphosphotyrosine immunoprecipitated only activity that had translocated to the plasma membrane, suggesting a role for CD45 phosphorylation in translocation. Western analysis confirmed the tyrosine phosphorylation of CD45 in plasma membranes of GM-CSF-treated neutrophils. Preincubation of plasma membranes of GM-CSF-stimulated neutrophils with cytosol from resting cells resulted in a time- and temperature-dependent loss in membrane PTPase as a consequence of the effects of a cytosolic inactivator. Cytosol obtained from stimulated neutrophils possessed substantially reduced levels of this PTPase inactivator. We conclude that activity of the catalytic component of membrane PTPase in circulating neutrophils is regulated by a cytosolic inactivator. Upon stimulation, intact CD45 PTPase is incorporated into the plasma membrane by a process that requires tyrosine phosphorylation. As a result of inhibition of the cytosolic inactivator, the translocated PTPase expresses full activity, thereby amplifying the potential regulatory influence of the enzyme on the cells' functional response.
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Cui, Y., KA Harvey, RA Siddiqui, J. Jansen, LP Akard, JM Thompson, JG Garcia, and D. English. "Cytosolic inactivation of translocated neutrophil plasma membrane protein tyrosine phosphatase." Blood 87, no. 1 (January 1, 1996): 341–49. http://dx.doi.org/10.1182/blood.v87.1.341.bloodjournal871341.
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Phosphotyrosine phosphatases (PTPases) regulate cellular metabolic activation by reversing the effects of tyrosine kinases activated earlier in intracellular signaling pathways. We coupled fluorescence-activated cell sorter analysis using anti-CD45 monoclonal antibody with direct measurements of enzyme activity in resolved subcellular fractions to define mechanisms that potentially regulate the availability and activity of CD45-PTPase on neutrophil plasma membranes. Neutrophils in freshly obtained blood as well as neutrophils freshly isolated from blood were found to possess detectable levels of plasma membrane CD45 as assessed by immunofluorescence. However, plasma membranes from these cells were essentially devoid of PTPase catalytic activity, which was largely confined to the specific granules. Granulocyte-macrophage colony-stimulating factor (GM-CSF) upregulated both the catalytic and antigenic components of CD45-PTPase on the plasma membrane of these cells. Upregulation was associated with a shift in the particulate subcellular PTPase catalytic activity from the specific granule fraction to the plasma membrane fraction. The tyrosine kinase inhibitor genistein abrogated GM-CSF-promoted upregulation of plasma membrane CD45 PTPase but did not prevent the GM-CSF-dependent decrease in specific granule catalytic activity. Anti-CD45 antibody immunoprecipitated PTPase activity from both specific granules of resting cells and plasma membranes of GM-CSF-treated cells. However, antiphosphotyrosine immunoprecipitated only activity that had translocated to the plasma membrane, suggesting a role for CD45 phosphorylation in translocation. Western analysis confirmed the tyrosine phosphorylation of CD45 in plasma membranes of GM-CSF-treated neutrophils. Preincubation of plasma membranes of GM-CSF-stimulated neutrophils with cytosol from resting cells resulted in a time- and temperature-dependent loss in membrane PTPase as a consequence of the effects of a cytosolic inactivator. Cytosol obtained from stimulated neutrophils possessed substantially reduced levels of this PTPase inactivator. We conclude that activity of the catalytic component of membrane PTPase in circulating neutrophils is regulated by a cytosolic inactivator. Upon stimulation, intact CD45 PTPase is incorporated into the plasma membrane by a process that requires tyrosine phosphorylation. As a result of inhibition of the cytosolic inactivator, the translocated PTPase expresses full activity, thereby amplifying the potential regulatory influence of the enzyme on the cells' functional response.
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Iwasaki, Yukimoto, Takafumi Itoh, Yusuke Hagi, Sakura Matsuta, Aki Nishiyama, Genki Chaya, Yuki Kobayashi, Kotaro Miura, and Setsuko Komatsu. "Proteomics Analysis of Plasma Membrane Fractions of the Root, Leaf, and Flower of Rice." International Journal of Molecular Sciences 21, no. 19 (September 23, 2020): 6988. http://dx.doi.org/10.3390/ijms21196988.
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The plasma membrane regulates biological processes such as ion transport, signal transduction, endocytosis, and cell differentiation/proliferation. To understand the functional characteristics and organ specificity of plasma membranes, plasma membrane protein fractions from rice root, etiolated leaf, green leaf, developing leaf sheath, and flower were analyzed by proteomics. Among the proteins identified, 511 were commonly accumulated in the five organs, whereas 270, 132, 359, 146, and 149 proteins were specifically accumulated in the root, etiolated leaf, green leaf, developing leaf sheath, and developing flower, respectively. The principle component analysis revealed that the functions of the plasma membrane in the root was different from those of green and etiolated leaves and that the plasma membrane protein composition of the leaf sheath was similar to that of the flower, but not that of the green leaf. Functional classification revealed that the root plasma membrane has more transport-related proteins than the leaf plasma membrane. Furthermore, the leaf sheath and flower plasma membranes were found to be richer in proteins involved in signaling and cell function than the green leaf plasma membrane. To validate the proteomics data, immunoblot analysis was carried out, focusing on four heterotrimeric G protein subunits, Gα, Gβ, Gγ1, and Gγ2. All subunits could be detected by both methods and, in particular, Gγ1 and Gγ2 required concentration by immunoprecipitation for mass spectrometry detection.
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Massaccesi, L., G. V. Melzi d’Eril, G. M. Colpi, G. Tettamanti, G. Goi, and A. Barassi. "Levels of Human Erythrocyte Membrane-Bound and Cytosolic Glycohydrolases Are Associated with Oxidative Stress in Erectile Dysfunction Patients." Disease Markers 2014 (2014): 1–8. http://dx.doi.org/10.1155/2014/485917.
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Oxidative stress (OS) and production of NO, by endothelium nitric oxide synthetase (eNOS), are involved in the pathophysiology of erectile dysfunction (ED). Moreover, OS induces modifications of the physicochemical properties of erythrocyte (RBC) plasma membranes and of the enzyme content of the same membranes. Due to their role in signalling early membrane alterations in OS-related pathologies, several plasma membrane and cytosolic glycohydrolases of human RBC have been proposed as new markers of cellular OS. In RBC, NOS can be activated and deactivated by phosphorylation/glycosylation. In this regulatory mechanism O-β-N-AcetylGlucosaminidase is a key enzyme. Cellular levels of O-GlcNAcylated proteins are related to OS; consequently dysfunctional eNOS O-GlcNAcylation seems to have a crucial role in ED. To elucidate the possible association between RBC glycohydrolases and OS, plasma hydroperoxides and antioxidant total defenses (Lag-time), cytosolic O-β-N-AcetylGlucosaminidase, cytosolic and membrane Hexosaminidase, membraneβ-D-Glucuronidase, andα-D-Glucosidase have been studied in 39 ED patients and 30 controls. In ED subjects hydroperoxides and plasma membrane glycohydrolases activities are significantly increased whereas Lag-time values and cytosolic glycohydrolases activities are significantly decreased. These data confirm the strong OS status in ED patients, the role of the studied glycohydrolases as early OS biomarker and suggest their possible use as specific marker of ED patients, particularly in those undergoing nutritional/pharmacological antioxidant therapy.
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Djukanović, L. J. D., J. I. Mimić-Oka, and J. B. Potić. "The Effects of Hemodialysis with Different Membranes on Middle Molecules and Uremic Neuropathy." International Journal of Artificial Organs 12, no. 1 (January 1989): 11–19. http://dx.doi.org/10.1177/039139888901200102.
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Twenty-four hemodialysis patients, 14 with uremic neuropathy and 10 symptom-free, were studied over 12 months. Cuprophan and AN 69 membrane dialyzers were used in their treatment in order to investigate the influence of different membranes on plasma levels of middle molecular weight substances (MMS) and uremic neuropathy. Hemodialysis with the cuprophan membrane caused no significant changes in plasma MMS levels or in the neurological condition of patients. The effect of dialysis with AN 69 membrane depended on initial plasma MMS levels. Initially high plasma MMS levels decreased significantly and significant improvement of neuropathy was achieved. In neuropathic patients with plasma MMS levels similar to those of symptom-free patients, hemodialysis with AN 69 membrane had no effect. These results suggest that hemodialysis with MMS high-permeability membranes may be recommended for neuropathic patients with high plasma MMS levels.
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KUSUMI, Akihiro. "Plasma Membrane Organizers." Seibutsu Butsuri 39, no. 1 (1999): 5–9. http://dx.doi.org/10.2142/biophys.39.5.
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SAKAI, Kiyotaka. "Membrane Plasma Separation." Journal of the Surface Finishing Society of Japan 46, no. 1 (1995): 2–6. http://dx.doi.org/10.4139/sfj.46.2.
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Vermeer, Bert J. "Plasma Membrane Receptors." Journal of Investigative Dermatology 88, no. 5 (May 1987): 529–31. http://dx.doi.org/10.1111/1523-1747.ep12470070.
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Malchesky, P. S., A. Sueoka, S. Matsubara, J. Wojcicki, and Y. Nosé. "Membrane Plasma Separation." Therapeutic Apheresis 4, no. 1 (February 2000): 47–53. http://dx.doi.org/10.1046/j.1526-0968.2000.00243.x.
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Crane, Frederick L., and Rita Barr. "Plasma membrane oxidoreductases." Critical Reviews in Plant Sciences 8, no. 4 (January 1989): 273–307. http://dx.doi.org/10.1080/07352688909382278.
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Maxfield, Frederick R. "Plasma membrane microdomains." Current Opinion in Cell Biology 14, no. 4 (August 2002): 483–87. http://dx.doi.org/10.1016/s0955-0674(02)00351-4.
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Wolff, J. "Plasma membrane tubulin." Biochimica et Biophysica Acta (BBA) - Biomembranes 1788, no. 7 (July 2009): 1415–33. http://dx.doi.org/10.1016/j.bbamem.2009.03.013.
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Harkes, Rolf, Anna Pezzarossa, Franziska Zosel, and Thomas Schmidt. "Plasma Membrane Organization." Biophysical Journal 100, no. 3 (February 2011): 340a. http://dx.doi.org/10.1016/j.bpj.2010.12.2060.
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Hristova, Kalina. "Plasma Membrane Models." Biophysical Journal 114, no. 3 (February 2018): 402a. http://dx.doi.org/10.1016/j.bpj.2017.11.2229.
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Andrews, Norma W., and Matthias Corrotte. "Plasma membrane repair." Current Biology 28, no. 8 (April 2018): R392—R397. http://dx.doi.org/10.1016/j.cub.2017.12.034.
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Betancourt, Miguel, Yvonne Ducolomb, Irma Jiménez, Eduardo Casas, Edmundo Bonilla, and Trish Berger. "Sperm plasma membrane receptors for the porcine oocyte plasma membrane." Zygote 6, no. 2 (May 1998): 155–58. http://dx.doi.org/10.1017/s0967199498000082.
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In vitro fertilisation (IVF) was used to assess the ability of solubilised sperm plasma membrane (PM) proteins to inhibit the interaction of intact gametes. This is a first step before evaluating the ability of individual isolated proteins to competitively inhibit sperm-oocyte interaction as part of the process of studying the molecular events of fertilisation. Porcine oocytes were aspirated from ovaries, matured for 48 h in Medium 199, and the zona pellucida (ZP) was removed by exposure to acid Tyrode's solution. ZP-free matured oocytes were exposed to 200–800 μg/ml sperm PM protein for 1 h prior to insemination and during gamete co-incubation. Twenty-four hours after insemination with 5 × 105 capacitated sperm/ml, the oocytes were fixed, stained and examined. Sperm PM protein clearly inhibited IVF in a concentration-dependent manner (r = −0.87). The inhibition index (I50%), representing the sperm PM protein concentration necessary to inhibit IVF to 50% of the control value, was 310 µg/ml. These results demonstrate that solubilised sperm PM protein inhibits the interaction of intact gametes as one might expect for receptor-ligand interactions. Furthermore, the complement of sperm PM proteins appeared maximally effective at a calculated concentration of 690 µm/ml, providing a foundation for further studies with individual proteins.
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Hanspal, Manjit, David E. Golan, Yva Smockova, Scott J. Yi, Michael R. Cho, Shih-Chun Liu, and Jiri Palek. "Temporal Synthesis of Band 3 Oligomers During Terminal Maturation of Mouse Erythroblasts. Dimers and Tetramers Exist in the Membrane as Preformed Stable Species." Blood 92, no. 1 (July 1, 1998): 329–38. http://dx.doi.org/10.1182/blood.v92.1.329.413k20_329_338.
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Band 3, the anion transport protein of the erythrocyte membrane, exists in the membrane as a mixture of dimers (B3D) and tetramers (B3T). The dimers are not linked to the skeleton and constitute the free mobile band 3 fraction. The tetramers are linked to the skeleton by their interaction with ankyrin. In this report we have examined the temporal synthesis and assembly of band 3 oligomers into the plasma membrane during red cell maturation. The oligomeric state of newly synthesized band 3 in early and late erythroblasts was analyzed by size-exclusion high-pressure liquid chromatography of band 3 extracts derived by mild extraction of plasma membranes with the nonionic detergent C12E8 (octaethylene glycol n-dodecyl monoether). This analysis revealed that at the early erythroblast stage, the newly synthesized band 3 is present predominantly as tetramers, whereas at the late stages of erythroid maturation, it is present exclusively as dimers. To examine whether the dimers and tetramers exist in the membrane as preformed stable species or whether they are interconvertible, the fate of band 3 species synthesized during erythroblast maturation was examined by pulse-chase analysis. We showed that the newly synthesized band 3 dimers and tetramers are stable and that there is no interconversion between these species in erythroblast membranes. Pulse-chase analysis followed by cellular fractionation showed that, in early erythroblasts, the newly synthesized band 3 tetramers are initially present in the microsomal fraction and later incorporated stably into the plasma membrane fraction. In contrast, in late erythroblasts the newly synthesized band 3 dimers move rapidly to the plasma membrane fraction but then recycle between the plasma membrane and microsomal fractions. Fluorescence photobleaching recovery studies showed that significant fractions of B3T and B3D are laterally mobile in early and late erythroblast plasma membranes, respectively, suggesting that many B3T-ankyrin complexes are unattached to the membrane skeleton in early erythroblasts and that the membrane skeleton has yet to become tightly organized in late erythroblasts. We postulate that in early erythroblasts, band 3 tetramers are transported through microsomes and stably incorporated into the plasma membrane. However, when ankyrin synthesis is downregulated in late erythroblasts, it appears that B3D are rapidly transported to the plasma membrane but then recycled between the plasma membrane and microsomal compartments. These observations may suggest novel roles for membrane skeletal proteins in stabilizing integral membrane protein oligomers at the plasma membrane and in regulating the endocytosis of such proteins.
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Scheifele, Lisa Z., Jonathan D. Rhoads, and Leslie J. Parent. "Specificity of Plasma Membrane Targeting by the Rous Sarcoma Virus Gag Protein." Journal of Virology 77, no. 1 (January 1, 2003): 470–80. http://dx.doi.org/10.1128/jvi.77.1.470-480.2003.
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ABSTRACT Budding of C-type retroviruses begins when the viral Gag polyprotein is directed to the plasma membrane by an N-terminal membrane-binding (M) domain. While dispersed basic amino acids within the M domain are critical for stable membrane association and consequent particle assembly, additional residues or motifs may be required for specific plasma membrane targeting and binding. We have identified an assembly-defective Rous sarcoma virus (RSV) Gag mutant that retains significant membrane affinity despite having a deletion of the fourth alpha-helix of the M domain. Examination of the mutant protein's subcellular distribution revealed that it was not localized to the plasma membrane but instead was mistargeted to intracytoplasmic membranes. Specific plasma membrane targeting was restored by the addition of myristate plus a single basic residue, by multiple basic residues, or by the heterologous hydrophobic membrane-binding domain from the cellular Fyn protein. These results suggest that the fourth alpha-helix of the RSV M domain promotes specific targeting of Gag to the plasma membrane, either through a direct interaction with plasma membrane phospholipids or a membrane-associated cellular factor or by maintaining the conformation of Gag to expose specific plasma membrane targeting sequences.
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OSADA, Yoshihito. "Plasma-polymerized thin film." membrane 10, no. 4 (1985): 215–23. http://dx.doi.org/10.5360/membrane.10.215.
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Enrich, C., P. Tabona, and W. H. Evans. "A two-dimensional electrophoretic analysis of the proteins and glycoproteins of liver plasma membrane domains and endosomes. Implications for endocytosis and transcytosis." Biochemical Journal 271, no. 1 (October 1, 1990): 171–78. http://dx.doi.org/10.1042/bj2710171.
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1. Polypeptides of liver plasma membrane fractions enriched in three surface domains of hepatocytes, blood-sinusoidal, lateral and bile canalicular, were analysed by isoelectric focusing (IEF) and non-equilibrium pH gel electrophoresis (NEPHGE) across a wide pH range, followed by SDS/PAGE. The overall Coomassie Blue-stained polypeptide patterns in the fractions were different. lateral plasma membrane fractions contained a characteristically higher number of polypeptides focusing at the basic pH range, whereas few basic polypeptides were present in sinusoidal plasma membrane fractions. The glycoproteins in these plasma membrane fractions stained by a lectin overlay technique with radio-iodinated concanavalin A, wheat-germ agglutinin and a slug lectin, were also different. 2. The polypeptides and glycoproteins of ‘early’ and ‘late’ endosome fractions were also compared by two-dimensional electrophoresis. Their composition was shown by Coomassie Blue staining, lectin overlay staining and in membranes metabolically labelled with [35S]methionine to be generally similar. The glycoproteins of sinusoidal plasma membranes and early and late endosomes were generally similar, but major differences in polypeptides of molecular mass 20-50 kDa, pI 7.5-8.5, in plasma membranes and endosomes were demonstrated, with a specific population of basic (pI 8-9) low-molecular-mass polypeptides being present at highest levels in ‘late’ endosomal fractions (shown by Coomassie Blue staining). 3. Analysis of the distribution of three specific membrane glycoproteins identified by using immunoblotting techniques showed that the asialoglycoprotein and the divalent-cation-sensitive mannose 6-phosphate receptors were present in sinusoidal plasma membrane and in early and late endocytic fractions: they were not detected in canalicular plasma membrane fractions. In contrast, 5′-nucleotidase was detected in all fractions examined. The role of the endocytic compartment in regulating trafficking pathways between the plasma membrane domains of the hepatocyte is discussed.
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Lee, E. G., S. J. Marciniak, C. M. MacLean, and J. M. Edwardson. "Pancreatic plasma membranes: promiscuous partners in membrane fusion." Biochemical Journal 298, no. 3 (March 15, 1994): 599–604. http://dx.doi.org/10.1042/bj2980599.
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We have developed a system in which the fusion of pancreatic plasma membranes with zymogen granules can be studied in vitro. We show here that pancreatic plasma membranes fuse not only with pancreatic zymogen granules but also with parotid secretory granules. In contrast, parotid membranes fuse only with parotid granules and not with pancreatic granules. The extent of fusion is insensitive to Ca2+ for all combinations of plasma membranes and granules. Guanosine 5′-[gamma-thio]triphosphate (GTP[S]), on the other hand, stimulates fusion of pancreatic membranes with both pancreatic granules and parotid granules, but inhibits fusion between parotid membranes and parotid granules.
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Wang, Jingshi, Xiao Chen, Rackel Reis, Zhiqiang Chen, Nick Milne, Bjorn Winther-Jensen, Lingxue Kong, and Ludovic Dumée. "Plasma Modification and Synthesis of Membrane Materials—A Mechanistic Review." Membranes 8, no. 3 (August 3, 2018): 56. http://dx.doi.org/10.3390/membranes8030056.
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Although commercial membranes are well established materials for water desalination and wastewater treatment, modification on commercial membranes is still necessary to deliver high-performance with enhanced flux and/or selectivity and fouling resistance. A modification method with plasma techniques has been extensively applied for high-performance membrane production. The paper presents a mechanistic review on the impact of plasma gas and polymerization, at either low pressure or atmospheric pressure on the material properties and performance of the modified membranes. At first, plasma conditions at low-pressure such as plasma power, gas or monomer flow rate, reactor pressure, and treatment duration which affect the chemical structure, surface hydrophilicity, morphology, as well as performance of the membranes have been discussed. The underlying mechanisms of plasma gas and polymerization have been highlighted. Thereafter, the recent research in plasma techniques toward membrane modification at atmospheric environment has been critically evaluated. The research focuses of future plasma-related membrane modification, and fabrication studies have been predicted to closely relate with the implementation of the atmospheric-pressure processes at the large-scale.
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Parmryd, Ingela, and Jeremy Adler. "Plasma Membrane Topology and Membrane Models." Biophysical Journal 96, no. 3 (February 2009): 282a. http://dx.doi.org/10.1016/j.bpj.2008.12.1395.
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Chen, Jing, and Lazaro J. Mandel. "Role of water and electrolyte influxes in anoxic plasma membrane disruption." American Journal of Physiology-Cell Physiology 273, no. 4 (October 1, 1997): C1341—C1348. http://dx.doi.org/10.1152/ajpcell.1997.273.4.c1341.
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The role of water and electrolyte influxes in anoxia-induced plasma membrane disruption was investigated using rabbit proximal tubule suspension. The results indicated that normal proximal tubule (PT) cells have a great capacity for expanding cell volume in response to water influx, whereas anoxia increases the susceptibility to water influx-induced disruption, and this was attenuated by glycine. However, resistance of anoxic plasma membranes to water influx-induced stress is not lost, although their mechanical strength was diminished, compared with normoxic membranes. Anoxic membranes did not disrupt under an intra-to-extracellular osmotic difference as great as 150 mosM. Potentiating or attenuating water influx by incubating PT cells in hypotonic or hypertonic medium, respectively, during anoxia, did not affect anoxia-induced membrane disruption. After the transmembrane electrolyte concentration gradient was eliminated by a “intracellular” buffer or by permeabilizing the plasma membrane to molecules <4 kDa using α-toxin, anoxia still caused further membrane disruption that was prevented by glycine or low pH. These results demonstrate that 1) water or net electrolyte influxes are probably not a primary cause for anoxia-induced membrane disruption and 2) glycine could prevent the plasma membrane disruption during anoxia independently from its effect on transmembrane electrolyte or water influxes. The present data support a biochemical rather than a mechanical alteration of the plasma membrane as the underlying cause of membrane disruption during anoxia.
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Sueoka, Akinori. "Development of Membrane for Plasma Separation." membrane 19, no. 6 (1994): 382–91. http://dx.doi.org/10.5360/membrane.19.382.
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Casares, Doralicia, Pablo V. Escribá, and Catalina Ana Rosselló. "Membrane Lipid Composition: Effect on Membrane and Organelle Structure, Function and Compartmentalization and Therapeutic Avenues." International Journal of Molecular Sciences 20, no. 9 (May 1, 2019): 2167. http://dx.doi.org/10.3390/ijms20092167.
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Biological membranes are key elements for the maintenance of cell architecture and physiology. Beyond a pure barrier separating the inner space of the cell from the outer, the plasma membrane is a scaffold and player in cell-to-cell communication and the initiation of intracellular signals among other functions. Critical to this function is the plasma membrane compartmentalization in lipid microdomains that control the localization and productive interactions of proteins involved in cell signal propagation. In addition, cells are divided into compartments limited by other membranes whose integrity and homeostasis are finely controlled, and which determine the identity and function of the different organelles. Here, we review current knowledge on membrane lipid composition in the plasma membrane and endomembrane compartments, emphasizing its role in sustaining organelle structure and function. The correct composition and structure of cell membranes define key pathophysiological aspects of cells. Therefore, we explore the therapeutic potential of manipulating membrane lipid composition with approaches like membrane lipid therapy, aiming to normalize cell functions through the modification of membrane lipid bilayers.
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Bokkala, S., S. S. el-Daher, V. V. Kakkar, F. Wuytack, and K. S. Authi. "Localization and identification of Ca2+ATPases in highly purified human platelet plasma and intracellular membranes. Evidence that the monoclonal antibody PL/IM 430 recognizes the SERCA 3 Ca2+ATPase in human platelets." Biochemical Journal 306, no. 3 (March 15, 1995): 837–42. http://dx.doi.org/10.1042/bj3060837.
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The Ca2+ATPase activities of highly purified human platelet membranes prepared by high-voltage free-flow electrophoresis have been analysed by using [gamma-32P]ATP hydrolysis, recognition by antibodies and phosphoenzyme-complex formation. The Ca2+ATPase activity present in mixed membranes was found to be predominantly associated with intracellular membranes after subfractionation, with only a low level of activity associated with plasma membranes. The intracellular-membrane Ca2+ATPase activity was inhibited totally with thapsigargin (Tg), whereas the plasma-membrane Ca2+ATPase was not significantly affected, suggesting that the latter does not belong to the SERCA (sarco-endoplasmic-reticulum Ca2+ATPase) class. A monoclonal antibody, 5F10, raised to the red-cell membrane Ca2+ATPase [Cheng, Magocsi, Cooper, Penniston and Borke (1993) Cell Physiol. Biochem. 4, 31-43] recognized two bands at 135 and 150 kDa in mixed membranes and plasma membranes, and the corresponding bands in red-blood-cell membranes, confirming the Ca2+ATPase to be of the PMCA (plasma-membrane Ca2+ATPase) type. No recognition of any band was detected in intracellular membranes. Identification of the intracellular-membrane Ca2+ATPase activity was carried out with polyclonal antibodies with known specificity towards SERCA 2b (S.2b) and SERCA 3 (N89), and a monoclonal antibody, PL/IM 430, raised against platelet intracellular membranes. All of these antibodies recognized the 100 kDa Ca2+ATPase in mixed membranes and intracellular membranes, with little or no recognition of the activity in the plasma membranes. In some membrane preparations the antibody PL/IM 430 and antiserum N89 recognized similar degradation products, of 74, 70 and 40 kDa, in the intracellular-membrane fraction. The Ca2+ATPase recognized by PL/IM 430 was immunoprecipitated, and the immunoprecipitated protein was specifically recognized by the antiserum N89, but not by S.2b. Analysis of the phosphoenzyme-complex formation revealed potent phosphorylation of the 100 and 74 kDa peptides, both recognized by PL/IM 430 and N89. These studies report the presence of a PMCA in a purified plasma-membrane fraction from human platelets, and that the antibody PL/IM 430 recognizes the SERCA 3 Ca2+ATPase in intracellular membranes.
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Ronen, R., Z. Lipsker, L. Sonego, and Susan Lurie. "PLASMA MEMBRANE ATPASE ISOLATED FROM GREEN BELL PEPPER FRUIT BY TWO-PHASE PARTITIONING OR SUCROSE DENSITY GRADIENT." Israel Journal of Plant Sciences 42, no. 1 (May 13, 1994): 15–27. http://dx.doi.org/10.1080/07929978.1994.10676553.
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Plasma membrane was isolated from mature green bell pepper fruit by two-phase partitioning or by sucrose density gradient. The yield of plasma membrane was higher from the sucrose density gradient, but the two-phase system was less contaminated by other membranes, particularly those from chloroplasts and mitochondria. In the two-phase partitioned membranes, ATPase activity was stimulated by Triton X-100 by 100% and in sucrose density gradient membranes by 40%. Plasma membranes from two-phase partitioning exhibited simultaneous proton pumping and ATP hydrolysis, while the sucrose density purified membranes did not. Immunoblotting with ATPase antibody showed enrichment of plasma membrane ATPase in both the U3 phase of the two-phase system, and the 34% sucrose fraction of the sucrose gradient. However, the two-phase partitioned membranes were superior to those prepared by sucrose density for investigating functions of the ATPase.
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Sehgal, S., B. P. Nayak, I. Haque, and R. Tiwari. "Comparison of Fabrication Process of Poly(methyl methacrylate) (PMMA) Membranes and their Amine Functionalization Studies for Application in Biosensing." Asian Journal of Chemistry 36, no. 9 (August 30, 2024): 2056–62. http://dx.doi.org/10.14233/ajchem.2024.32116.
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The comparison of the fabrication process of poly(methyl methacrylate) (PMMA) membranes and their functionalization on the basis of various characterization studies to produce a robust, stable and adherent amine functionalized surface for application in biosensing was attempted in present work. PMMA membrane fabricated using solution casting and compression moulding were characterized morphologically using electron microscopy (SEM) and functionalized with O2, N2 and He plasma at the same discharge conditions followed by deposition of (3-aminopropyl)triethoxysilane (3-APTES), an alkoxysilane, on the membranes in three different concentrations (5%, 10% and 15%). Using contact angle measurements, changes within the surface hydrophilicity were determined for pristine PMMA, plasma treated and plasma followed by 3-APTES treated PMMA membranes while amine functionalization was confirmed by Fourier transform infrared spectroscopy (FTIR). Further, the density of reactive amine groups on the membrane was estimated using fluorescent reagent in confocal microscope, which revealed that although all the plasma and 3-APTES treatments resulted in functionalization of PMMA membranes, however treatment with He plasma and 10% APTES displayed 10 to 15 times more reactive amine groups on PMMA membranes in comparison to the other plasma and 3-APTES treatments. Moreover, among the two fabricated membranes, it was found that solution casted PMMA membrane yielded twice more reactive amine groups than the compression moulded membrane. The results suggested the stability and ability of He plasma and 10% APTES treated PMMA membrane to immobilize DNA and other biomolecules efficiently and thereby can act as biosensing platform.
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Ríos-Medina, Yolanda, Pedro Rico-Chávez, Ivette Martínez-Vieyra, Juan C. Durán-Álvarez, Mario Rodriguez-Varela, Ruth Rincón-Heredia, César Reyes-López, and Doris Cerecedo. "Altered Plasma Membrane Lipid Composition in Hypertensive Neutrophils Impacts Epithelial Sodium Channel (ENaC) Endocytosis." International Journal of Molecular Sciences 25, no. 9 (April 30, 2024): 4939. http://dx.doi.org/10.3390/ijms25094939.
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Biological membranes are composed of a lipid bilayer with embedded proteins, including ion channels like the epithelial sodium channel (ENaC), which are critical for sodium homeostasis and implicated in arterial hypertension (HTN). Changes in the lipid composition of the plasma membrane can significantly impact cellular processes related to physiological functions. We hypothesized that the observed overexpression of ENaC in neutrophils from HTN patients might result from alterations in the structuring domains within the plasma membrane, disrupting the endocytic processes responsible for ENaC retrieval. This study assessed the structural lipid composition of neutrophil plasma membranes from HTN patients along with the expression patterns of key elements regulating ENaC at the plasma membrane. Our findings suggest alterations in microdomain structure and SGK1 kinase activity, which could prolong ENaC presence on the plasma membrane. Additionally, we propose that the proteasomal and lysosomal degradation pathways are insufficient to diminish ENaC presence at the plasma membrane in HTN. These results highlight the importance of understanding ENaC retrieval mechanisms and suggest that targeting these mechanisms could provide insights for developing drugs to prevent and treat HTN.
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Miyata, H., B. Bowers, and E. D. Korn. "Plasma membrane association of Acanthamoeba myosin I." Journal of Cell Biology 109, no. 4 (October 1, 1989): 1519–28. http://dx.doi.org/10.1083/jcb.109.4.1519.
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Myosin I accounted for approximately 2% of the protein of highly purified plasma membranes, which represents about a tenfold enrichment over its concentration in the total cell homogenate. This localization is consistent with immunofluorescence analysis of cells that shows myosin I at or near the plasma membrane as well as diffusely distributed in the cytoplasm with no apparent association with cytoplasmic organelles or vesicles identifiable at the level of light microscopy. Myosin II was not detected in the purified plasma membrane fraction. Although actin was present in about a tenfold molar excess relative to myosin I, several lines of evidence suggest that the principal linkage of myosin I with the plasma membrane is not through F-actin: (a) KI extracted much more actin than myosin I from the plasma membrane fraction; (b) higher ionic strength was required to solubilize the membrane-bound myosin I than to dissociate a complex of purified myosin I and F-actin; and (c) added purified myosin I bound to KI-extracted plasma membranes in a saturable manner with maximum binding four- to fivefold greater than the actin content and with much greater affinity than for pure F-actin (apparent KD of 30-50 nM vs. 10-40 microM in 0.1 M KCl plus 2 mM MgATP). Thus, neither the MgATP-sensitive actin-binding site in the NH2-terminal end of the myosin I heavy chain nor the MgATP-insensitive actin-binding site in the COOH-terminal end of the heavy chain appeared to be the principal mechanism of binding of myosin I to plasma membranes through F-actin. Furthermore, the MgATP-sensitive actin-binding site of membrane-bound myosin I was still available to bind added F-actin. However, the MgATP-insensitive actin-binding site appeared to be unable to bind added F-actin, suggesting that the membrane-binding site is near enough to this site to block sterically its interaction with actin.