Showing papers on "Phosphatidylethanolamine published in 2001"
TL;DR: It is shown that treatment of Jurkat T cells with polyunsaturated eicosapentaenoic acid results in marked enrichment of PUFAs (20:5; 22:5) in lipids from isolated rafts, which provides strong evidence that displacement of acylated proteins from rafts in PUFA-treated T cells is predominantly due to altered raft lipid composition.
338 citations
TL;DR: Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry is an established tool for the analysis of proteins, whereas it gained by far less interest in the field of lipid analysis, but this method works well with phospholipids as well as organic cell extracts and provides high sensitivity and reproducibility.
307 citations
TL;DR: Three different pathways lead to the synthesis of phosphatidylethanolamine (PtdEtn) in yeast, one of which is localized to the inner mitochondrial membrane, and a series of deletion mutants in which different combinations of the pathways are blocked showed an enhanced formation of respiration-deficient cells.
Abstract: Three different pathways lead to the synthesis of phosphatidylethanolamine (PtdEtn) in yeast, one of which is localized to the inner mitochondrial membrane. To study the contribution of each of these pathways, we constructed a series of deletion mutants in which different combinations of the pathways are blocked. Analysis of their growth phenotypes revealed that a minimal level of PtdEtn is essential for growth. On fermentable carbon sources such as glucose, endogenous ethanolaminephosphate provided by sphingolipid catabolism is sufficient to allow synthesis of the essential amount of PtdEtn through the cytidyldiphosphate (CDP)-ethanolamine pathway. On nonfermentable carbon sources, however, a higher level of PtdEtn is required for growth, and the amounts of PtdEtn produced through the CDP-ethanolamine pathway and by extramitochondrial phosphatidylserine decarboxylase 2 are not sufficient to maintain growth unless the action of the former pathway is enhanced by supplementing the growth medium with ethanolamine. Thus, in the absence of such supplementation, production of PtdEtn by mitochondrial phosphatidylserine decarboxylase 1 becomes essential. In psd1D strains or cho1D strains (defective in phosphatidylserine synthesis), which contain decreased amounts of PtdEtn, the growth rate on nonfermentable carbon sources correlates with the content of PtdEtn in mitochondria, suggesting that import of PtdEtn into this organelle becomes growth limiting. Although morphological and biochemical analysis revealed no obvious defects of PtdEtn-depleted mitochondria, the mutants exhibited an enhanced formation of respiration-deficient cells. Synthesis of glycosylphosphatidylinositol-anchored proteins is also impaired in PtdEtn-depleted cells, as demonstrated by delayed maturation of Gas1p. Carboxypeptidase Y and invertase, on the other hand, were processed with wild-type kinetics. Thus, PtdEtn depletion does not affect protein secretion in general, suggesting that high levels of nonbilayer-forming lipids such as PtdEtn are not essential for membrane vesicle fusion processes in vivo.
266 citations
TL;DR: Plasma membranes of wheat grown under metal deficiency and excess showed increased NADPH-dependent superoxide-producing oxidase activities, whereas membrane-bound lipoxygenase was not increased or activated due to Cu treatments.
Abstract: The effects of in vivo copper on the lipid composition of root plasma membrane and the activities of membrane-bound enzymes, such as NADPH-dependent oxidases and lipoxygenase, were studied. Plants were grown in hydroponic culture for 11 d without Cu supply or in the presence of 50 microM Cu. Control plants were supplied with 0.3 microM Cu. Growth of roots was severely affected in the 50 microM Cu-grown plants, whereas roots grown in Cu-deficient solution did not show any difference in comparison with the control. The 50 microM Cu concentration caused an increase in the leakage of K(+) ions as well. Excess metal supply resulted in a decrease in the total lipid content of plasma membrane, a higher phospholipid amount and a reduction of steryl lipids (free sterols, steryl glycosides and acylated steryl glycosides). Cu depletion in the growth solution had only a slight effect on the plasma membrane lipid composition. In comparison with the control, only the excess of Cu caused a decrease in the lipid to protein ratio as well as a change in the phospholipid composition, with a lower phosphatidylcholine to phosphatidylethanolamine ratio. The degree of unsaturation of root plasma membranes decreased following the 0 Cu treatment and even more after the 50 microM Cu supply. Plasma membranes of wheat grown under metal deficiency and excess showed increased NADPH-dependent superoxide-producing oxidase activities, whereas membrane-bound lipoxygenase was not increased or activated due to Cu treatments. The consequences of changes in plasma membrane lipid composition and activated oxygen production as a result of Cu treatments are discussed.
231 citations
TL;DR: Evidence that PLSCR1 may serve functions other than its proposed activity as PL scramblase is presented, and the functional significance of such interaction remains to be elucidated.
Abstract: Plasma membrane phospholipid asymmetry is maintained by an aminophospholipid translocase that transports phosphatidylserine (PS) and phosphatidylethanolamine (PE) from outer to inner membrane leaflet. Cell activation or injury leads to redistribution of all major lipid classes within the plasma membrane, resulting in surface exposure of PS and PE. Cell surface-exposed PS can serve as receptor sites for coagulation enzyme complexes, and contributes to cell clearance by the reticuloendothelial system. The mechanism(s) by which this PL ”scrambling” occurs is poorly understood. A protein called phospholipid scramblase (PLSCR1) has been cloned that exhibits Ca2+-activated PL scrambling activity in vitro. PLSCR1 belongs to a new family of proteins with no apparent homology to other known proteins. PLSCR1 is palmitoylated and contains a potential protein kinase C phosphorylation site. It further contains multiple PxxP and PPxY motifs, representing potential binding motifs for SH3 and WW domains implicated in mediating protein-protein interactions. Although at least two proteins have been shown to associate with PLSCR1, the functional significance of such interaction remains to be elucidated. Evidence that PLSCR1 may serve functions other than its proposed activity as PL scramblase is also presented.
212 citations
TL;DR: It is suggested that the insertion of the toxin channel could imply the formation in the bilayer of a nonlamellar structure, a toroidal lipid pore, as in the case of PC/SM mixtures, where permeabilization was optimal when the molar ratio of PA/SM was ~1.
186 citations
TL;DR: Results suggest that P-glycoprotein carries out both lipid translocation and drug transport by the same path, and may be a generic flippase for hydrophobic molecules with the correct steric attributes that are present within the membrane interior.
Abstract: The P-glycoprotein multidrug transporter acts as an ATP-powered efflux pump for a large variety of hydrophobic drugs, natural products, and peptides. The protein is proposed to interact with its substrates within the hydrophobic interior of the membrane. There is indirect evidence to suggest that P-glycoprotein can also transport, or "flip", short chain fluorescent lipids between leaflets of the membrane. In this study, we use a fluorescence quenching technique to directly show that P-glycoprotein reconstituted into proteoliposomes translocates a wide variety of NBD lipids from the outer to the inner leaflet of the bilayer. Flippase activity depended on ATP hydrolysis at the outer surface of the proteoliposome, and was inhibited by vanadate. P-Glycoprotein exhibited a broad specificity for phospholipids, and translocated phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, and sphingomyelin. Lipid derivatives that were flipped included molecules with long, short, unsaturated, and saturated acyl chains and species with the NBD group covalently linked to either acyl chains or the headgroup. The extent of lipid translocation from the outer to the inner leaflet in a 20 min period at 37 degrees C was directly estimated, and fell in the range of 0.36-1.83 nmol/mg of protein. Phospholipid flipping was inhibited in a concentration-dependent, saturable fashion by various substrates and modulators, including vinblastine, verapamil, and cyclosporin A, and the efficiency of inhibition correlated well with the affinity of binding to Pgp. Taken together, these results suggest that P-glycoprotein carries out both lipid translocation and drug transport by the same path. The transporter may be a generic flippase for hydrophobic molecules with the correct steric attributes that are present within the membrane interior.
163 citations
TL;DR: In this article, chemical analysis was performed on samples of horse mackerel (Trachurus trachurus L) caught monthly off the Portuguese coast throughout a period of one year (May 1997-April 1998) in the period between August and January the amount of total lipids present was recorded showing a minimum in February Protein content remained fairly constant during the whole one-year period
Abstract: Chemical analysis was performed on samples of horse mackerel (Trachurus trachurus L) caught monthly off the Portuguese coast throughout a period of one year (May 1997–April 1998) In the period between August and January the amount of total lipids present was recorded showing a minimum in February Protein content remained fairly constant during the whole one-year period Seasonal variation of lipid classes was followed and fatty acid profiles of total, polar and non-polar lipids as well as that of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) were determined The non-polar lipids were the ever dominant group, mainly composed of triacylglycerols Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) were the main phospholipids mainly containing 20:5ω3 and 22:6ω3, but PE was richer in 22:6ω3
143 citations
TL;DR: In this article, an 18-residue linear cationic peptide, (KIGAKI)3-NH2, was designed to form a highly amphipathic β-sheet.
132 citations
TL;DR: The presence of the capsular polysaccharide turned out to be essential for viability without LPS, as demonstrated by using a strain in which LPS biosynthesis could be switched on or off through a tac promoter‐controlled lpxA gene.
Abstract: In the pathogen Neisseria meningitidis, a completely lipopolysaccharide (LPS)-deficient but viable mutant can be obtained by insertional inactivation of the lpxA gene, encoding UDP-GlcNAc acyltransferase required for the first step of lipid A biosynthesis. To study how outer membrane structure and biogenesis are affected by the absence of this normally major component, inner and outer membranes were separated and their composition analysed. The expression and assembly of integral outer membrane proteins appeared largely unaffected. However, the expression of iron limitation-inducible, cell surface-exposed lipoproteins was greatly reduced. Major changes were seen in the phospholipid composition, with a shift towards phosphatidylethanolamine and phosphatidylglycerol species containing mostly shorter chain, saturated fatty acids, one of which was unique to the LPS-deficient outer membrane. The presence of the capsular polysaccharide turned out to be essential for viability without LPS, as demonstrated by using a strain in which LPS biosynthesis could be switched on or off through a tac promoter-controlled lpxA gene. Taken together, these results can help to explain why meningococci have the unique ability to survive without LPS.
130 citations
TL;DR: These studies show that maternal dietary fatty acids may alter fetal brain growth cone (n-6) and ( n-3) fatty acids, and neurotransmitters involved in neurite extension, target finding and synaptogenesis.
Abstract: The importance of maternal dietary fatty acids on arachidonic acid [AA; 20:4(n-6)] and docosahexaenoic acid [DHA; 22:6(n-3)] in fetal brain nerve growth cone membranes and monoaminergic neurotransmitters was investigated. Rats were fed purified diets containing 20 g/100 g safflower oil with 74.3% 18:2(n-6), 0.2% 18:3(n-3), soybean oil with 55.4% 18:2(n-6), 7.7% 18:3(n-3) or high fish oil with 24.6% 22:6(n-3) through gestation. Tissue for rats within a litter were pooled at birth, brain growth cone membranes prepared and phosphatidylcholine (PC), phosphatidylserine (PS), phosphatidylethanolamine (PE) and phosphatidylinositol (PI) fatty acids quantified by gas-liquid chromatography. Dopamine, serotonin, and the metabolites 3,4-dihydroxyphenylacetic acid and homovanillic acid, and 5-hydroxyindolacetic acid were quantified by HPLC. Growth cone membranes from offspring of rats fed safflower oil had significantly lower, and offspring of rats fed high 22:6(n-3) fish oil had significantly higher 22:6(n-3) in PE, PS and PI than the soybean oil group. The growth cone membrane PC, PE and PS 20:4(n-6) was significantly lower in the fish oil than in the soybean or safflower oil groups. Serotonin concentration was significantly higher in brain of offspring in the safflower oil compared with the soybean oil group. The newborn brain dopamine was inversely related to PE DHA and PS DHA (P < 0.001), but positively related to PC AA (P < 0.05). These studies show that maternal dietary fatty acids may alter fetal brain growth cone (n-6) and (n-3) fatty acids, and neurotransmitters involved in neurite extension, target finding and synaptogenesis. The functional importance, however, is not known at this time.
TL;DR: There is a critical level of PtdEtn required to support growth at elevated temperature or on the nonfermentable carbon source lactate, as well as a novel lipid determined by mass spectrometry to be phosphatidylpropanolamine (PtdPrn), which can comprise up to 40% of the total phospholipid content in supplemented cells at the expense of phosph atidylcholine and PTDEtn.
TL;DR: The data demonstrate the existence of separate ethanolamine and choline kinases in mammals and show that ethanolamine kinase can be a rate-controlling step in PtdEtn biosynthesis.
TL;DR: In vivo protein synthesis experiments demonstrated that gentamicin reduced cellular protein synthesis after 2 d of treatment, and inhibition of phospholipid degradation was quantitatively the major contributor to the effects of Gentamicin on phospholIPid metabolism.
Abstract: Studies were undertaken to characterize the mechanism of aminoglycoside-induced nephrotoxicity. Early time points in gentamicin treatment (1 to 3 d) were used to investigate the development of toxic events without the complication of gross morphologic cellular alterations. Enzyme activities of cortical homogenates and brush border membrane (BBM) preparations documented little effect on specific activities or the ability to isolate representative membrane fractions. In vivo protein synthesis experiments demonstrated that gentamicin reduced cellular protein synthesis after 2 d of treatment. This inhibition increased to 50% on the third day. Total cellular proteins synthesis was inhibited to the same extent as BBM protein synthesis. However, gentamicin had different effects on homogenate versus BBM phospholipids. The total phospholipid contents in cortical homogenates and BBM from treated animals were increased, compared with control animals. A significant decrease in phospholipid synthesis was observed only in homogenates from treated animals. When effects on individual phospholipids were investigated, only an increase in phosphatidylinositol levels was observed in cortical homogenates from treated rats. However, gentamicin treatment was demonstrated to increase the levels of phosphatidylinositol and phosphatidylcholine, while decreasing the level of sphingomyelin (SPH), in BBM. Incorporation of (32)P into SPH, phosphatidylserine, and phosphatidylethanolamine was inhibited in cortical homogenates from gentamicin-treated animals; among BBM phospholipids, however, a significant decrease was observed only for SPH synthesis. It was concluded that inhibition of phospholipid degradation was quantitatively the major contributor to the effects of gentamicin on phospholipid metabolism. Confocal microscopic studies, using tracer amounts of fluorescently labeled gentamicin, revealed gentamicin in large, mostly basal structures. Correlative electron microscopic studies, using photo-oxidation techniques, demonstrated that these structures consisted of lysosomal, Golgi complex, and mitochondrial structures. These observations suggest retrograde trafficking of gentamicin and indicate a general mechanism of gentamicin-induced nephrotoxicity.
TL;DR: A detailed analysis of individual lipids and a characterization of the membrane fluidity of corn (Zea mays L.) root plasma membranes isolated by phase-partitioning are provided.
Patent•
08 May 2001
TL;DR: In this paper, a preparation suitable for the prevention and/or treatment of vascular disorders, comprising the following fractions: fraction a) long chain polyunsaturated fatty acids; fraction b) phospholipids, which fraction contains at least two different phospholipsids selected from the group consisting of phosphatidylserine; and fraction c) compounds which are a factor in methionine metabolism.
Abstract: The present invention relates to a preparation suitable for the prevention and/or treatment of vascular disorders, comprising the following fractions: fraction a) long chain polyunsaturated fatty acids; fraction b) phospholipids, which fraction contains at least two different phospholipids selected from the group consisting of phosphatidylserine; phosphatidylinositol, phosphatidylcholine and phosphatidylethanolamine. fraction c) compounds which are a factor in methionine metabolism, which fraction contains at least one member selected from the group consisting of folic acid, vitamin B12, vitamin B6, magnesium and zinc.
TL;DR: Observations imply that the membrane dipole potential plays an important role as a modulator of molecule-membrane interactions in these membrane structures and is suggested to contribute to the altered behavior of receptor-mediated signaling systems in membrane rafts.
TL;DR: Electrospray ionization mass spectrometry is used for quantitative determination of lipid molecular species in human fibroblasts and their plasma membrane incorporated into enveloped viruses to suggest that remodeling of phospholipids toward higher unsaturation may serve as both an acute and a long-term adaptive mechanism in human cellular membranes against cholesterol excess.
Abstract: Here we used electrospray ionization mass spectrometry for quantitative determination of lipid molecular species in human fibroblasts and their plasma membrane incorporated into enveloped viruses. Both influenza virus selecting ordered domains and vesicular stomatitis virus (VSV) depleted of such domains [Scheiffele, P., et al. (1999) J. Biol. Chem. 274, 2038-2044] were analyzed. The major difference between influenza and VSV was found to be a marked enrichment of glycosphingolipids in the former. The effect of chronic cholesterol loading on viral lipid composition was studied in Niemann-Pick type C (NPC) fibroblasts. Both NPC-derived influenza and VSV virions contained increased amounts of cholesterol. Furthermore, polyunsaturated phosphatidylcholine, phosphatidylethanolamine, and phosphatidylserine were enriched in NPC-derived virions at the expense of the monounsaturated ones. When normal fibroblasts were acutely loaded with cholesterol using cyclodextrin complexes, an adjustment toward increasingly unsaturated phospholipid species was observed, most clearly for phosphatidylcholine and sphingomyelin. Our results provide evidence that (1) glycosphingolipids are enriched in domains through which influenza virus buds, (2) chronic cholesterol accumulation increases the cholesterol content of both glycosphingolipid-enriched and intervening plasma membrane domains, and (3) an increase in membrane cholesterol content is accompanied by an increased level of polyunsaturated species of the major membrane phospholipids. We suggest that remodeling of phospholipids toward higher unsaturation may serve as both an acute and a long-term adaptive mechanism in human cellular membranes against cholesterol excess.
TL;DR: It is found that PDC-109 alters the membrane structure of lipid vesicles as well as of bovine epididymal spermatozoa in that the mobility of spin-labeled phospholipids was reduced in the presence of the protein.
Abstract: PDC-109 is the main component of bovine seminal plasma and has been suggested to play an important role in the genesis of bovine sperm cells. Here, the effect of binding of PDC-109 to membranes on the structure and physical properties of the lipid phase was investigated. For that, ESR measurements were undertaken on model membranes (lipid vesicles) and on biological membranes (epididymal spermatozoa) by employing various spin-labeled phospholipids. We found that PDC-109 alters the membrane structure of lipid vesicles as well as of bovine epididymal spermatozoa in that the mobility of spin-labeled phospholipids was reduced in the presence of the protein. This immobilizing effect of the protein was not restricted to analogues of phosphatidylcholine but was also detected with spin-labeled phosphatidylethanolamine. However, the extent of immobilization was lower for phosphatidylethanolamine compared with phosphatidylcholine, supporting the lipid headgroup specificity of the protein. Besides phospholipid headg...
TL;DR: The presence of cholesterol attenuates but does not abolish the interactions of GS with, and the characteristic effects of GS on, phospholipid bilayers, which may explain why it is more potent at disrupting cholesterol-free bacterial than cholesterol-containing eukaryotic membranes while nevertheless disrupting the integrity of the latter at higher peptide concentrations.
TL;DR: The induction of the pEtN transferase by 5–50 mm CaCl2 suggests possible role(s) in establishing transformation competence or resisting environmental stress, and represents the first example of a regulated covalent modification of the inner core of E. coli LPS.
TL;DR: It is suggested that a membrane domain containing cholesterol, phosphatidylcholine, sphingolipids and proteins can be separated from the total cell membranes by anti‐GD3 antibody immunoprecipitation, and that the association of c‐Src, Fyn, Lyn, and TAG‐1 with the sphingoipid‐enriched domain is mediated by the interaction with a complex lipid environment, rather than by specific interactions with a single sphingosine species.
Abstract: Rat cerebellar granule cells differentiated in culture were fed [1–3H]sphingosine, allowing the metabolic radiolabelling of all cell sphingolipids and phosphatidylethanolamine. A detergent-insoluble sphingolipid-enriched membrane fraction, containing about 60% of cell sphingolipids, but only trace amounts of phosphatidylethanolamine, was prepared from [1–3H]sphingosine-fed cells by sucrose gradient centrifugation. This fraction was enriched in the Src family protein tyrosine kinases c-Src, Lyn and Fyn and in the GPI-anchored neuronal adhesion molecule TAG-1. The cell lysate and the sphingolipid-enriched membrane fraction were subjected to immunoprecipitation with anti-GD3 ganglioside monoclonal antibody R24, under experimental conditions designed to preserve the integrity of the domain. The radioactive lipid composition of the immunoprecipitates obtained from the cell lysate and from the sphingolipid-enriched fraction were very similar, and closely resembled the sphingolipid composition of the whole sphingolipid-enriched membrane fraction. In fact, the immunoprecipitates contained, together with GD3 ganglioside, all cell glycosphingolipids and sphingomyelin, whereas they did not contain phosphatidylethanolamine. Moreover, cholesterol and phosphatidylcholine were detected in the immunoprecipitates by qualitative TLC analysis followed by colourimetric visualization. c-Src, Lyn, Fyn and TAG-1 were associated with the anti-GD3 antibody immunoprecipitate. These proteins were not detected in the immunoprecipitates obtained under experimental conditions different from those designed to preserve the integrity of the domain. These data suggest that a membrane domain containing cholesterol, phosphatidylcholine, sphingolipids and proteins can be separated from the total cell membranes by anti-GD3 antibody immunoprecipitation, and that the association of c-Src, Fyn, Lyn, and TAG-1 with the sphingolipid-enriched domain is mediated by the interaction with a complex lipid environment, rather than by specific interactions with a single sphingolipid species.
TL;DR: It is proposed that M‐C6‐NBD‐PC and M‐ c6‐ NBD‐PE are transported across the plasma membrane to the cytosolic leaflet by a protein‐mediated, energy‐dependent mechanism and are spontaneously distributed to the nuclear envelope/ER and mitochondria.
Abstract: The internalization and distribution of fluorescent analogs of phosphatidylcholine (M-C6-NBD-PC) and phosphatidylethanolamine (M-C6-NBD-PE) were studied in Saccharomyces cerevisiae. At normal growth temperatures, M-C6-NBD-PC was internalized predominantly to the vacuole and degraded. M-C6-NBD-PE was internalized to the nuclear envelope/ER and mitochondria, was not transported to the vacuole, and was not degraded. At 2°C, both were internalized to the nuclear envelope/ER and mitochondria by an energy-dependent, N-ethylmaleimide-sensitive process, and transport of M-C6-NBD-PC to and degradation in the vacuole was blocked. Internalization of neither phospholipid was reduced in the endocytosis-defective mutant, end4-1. However, following pre-incubation at 37°C, internalization of both phospholipids was inhibited at 2°C and 37°C in sec mutants defective in vesicular traffic. The sec18/NSF mutation was unique among the sec mutations in further blocking M-C6-NBD-PC translocation to the vacuole suggesting a dependence on membrane fusion. Based on these and previous observations, we propose that M-C6-NBD-PC and M-C6-NBD-PE are transported across the plasma membrane to the cytosolic leaflet by a protein-mediated, energy-dependent mechanism. From the cytosolic leaflet, both phospholipids are spontaneously distributed to the nuclear envelope/ER and mitochondria. Subsequently, M-C6-NBD-PC, but not M-C6-NBD-PE, is sorted by vesicular transport to the vacuole where it is degraded by lumenal hydrolases.
TL;DR: It could be shown that Amadori-PE extensively promotes lipid peroxidation even in the absence of transition metal ions like Cu(2+) and Fe(3+), which is supposed to be at least partially caused by the glycation of aminophospholipids.
TL;DR: A fluorescence quenching method using peptides containing 3,5-dibromotryrosine to measure oligomerization of model transmembrane alpha-helices in lipid bilayers finds that addition of cholesterol to form the liquid-ordered state led to increased dimerization but without phase separation.
Abstract: We have developed a fluorescence quenching method using peptides containing 3,5-dibromotryrosine to measure oligomerization of model transmembrane a-helices in lipid bilayers. Peptides of the type Ac-LysLysGlyLeu(m)XLeu(n)LysLysAla-amide where X is tryptophan or 3,5-dibromotyrosine were found to form heterodimers in bilayers of phosphatidylcholine in the liquid-crystalline phase. The free energy of dimer formation changed little with increasing number of Leu residues from 16 to 22 but increased with increasing phospholipid fatty acyl chain length, with a slope of about 0.5 kJ mol(-1) per fatty acyl chain carbon. Peptides were excluded from lipid in the gel phase, resulting in increased levels of oligomerization. Addition of cholesterol to form the liquid-ordered state led to increased dimerization but without phase separation. The presence of phosphatidylethanolamine had little effect on dimerization.
TL;DR: It is reported that CPT1- and E PT1-derived cholinephosphotransferase activities can significantly overlap in vivo such that EPT1 can contribute to 60% of net phosphatidylcholine synthesis via the Kennedy pathway.
Abstract: Phosphatidylcholine and phosphatidylethanolamine are the most abundant phospholipids in eukaryotic cells and thus have major roles in the formation and maintenance of vesicular membranes. In yeast,...
TL;DR: The interaction of the major acidic bovine seminal plasma protein, PDC-109, with dimyristoylphosphatidylcholine (DMPC) membranes has been investigated by spin-label electron spin resonance spectroscopy and indicates that the protein exhibits highest selectivity for the choline phospholipids phosphatidycholine and sphingomyelin under physiological conditions of pH and ionic strength.
TL;DR: The packing constraints of these phospholipids, major components of cytoplasmic bacterial membranes, may be of importance in the interaction with various solutes like antimicrobial peptides, and were explained based on the nature of the headgroups and the molecular geometry of the phospholIPids.
TL;DR: Experiments with phenylhydrazine, KCl, quinine, merocyanine 540, the calpain inhibitor E-64d, and the scramblase inhibitor R5421 revealed that neither phospholipid translocation nor vesicle release was required to induce susceptibility.
TL;DR: It is proposed that deacylation of PE and PC by phospholipase A2 to generate lysocompounds, followed by selective reacylated of lyso-PE in the inner leaflet, can account for the compositional and architectural peculiarities of bovine erythrocyte membranes.
Abstract: Ruminant erythrocytes are remarkable for their choline-phospholipid anomalies; namely, low or absent phosphatidylcholine (PC) along with high sphingomyelin levels. Here, we report another anomaly in bovine erythrocytes that affects aminophospholipids: phosphatidylethanolamine (PE) shows an extreme asymmetry, with only 2% of the total present in the outer leaflet. Furthermore, we found that phospholipase A2, an enzyme located on the external surface of the erythrocytes, shows higher activity against PC than against PE. In addition, we observed that acylation of PE is by far the most important biosynthetic event in this system. We propose that deacylation of PE and PC by phospholipase A2 to generate lysocompounds, followed by selective reacylation of lyso-PE in the inner leaflet, can account for the compositional and architectural peculiarities of bovine erythrocyte membranes.