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1
Solís-Calero, Christian, Joaquín Ortega-Castro, Juan Frau, and Francisco Muñoz. "Nonenzymatic Reactions above Phospholipid Surfaces of Biological Membranes: Reactivity of Phospholipids and Their Oxidation Derivatives." Oxidative Medicine and Cellular Longevity 2015 (2015): 1–22. http://dx.doi.org/10.1155/2015/319505.
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Phospholipids play multiple and essential roles in cells, as components of biological membranes. Although phospholipid bilayers provide the supporting matrix and surface for many enzymatic reactions, their inherent reactivity and possible catalytic role have not been highlighted. As other biomolecules, phospholipids are frequent targets of nonenzymatic modifications by reactive substances including oxidants and glycating agents which conduct to the formation of advanced lipoxidation end products (ALEs) and advanced glycation end products (AGEs). There are some theoretical studies about the mechanisms of reactions related to these processes on phosphatidylethanolamine surfaces, which hypothesize that cell membrane phospholipids surface environment could enhance some reactions through a catalyst effect. On the other hand, the phospholipid bilayers are susceptible to oxidative damage by oxidant agents as reactive oxygen species (ROS). Molecular dynamics simulations performed on phospholipid bilayers models, which include modified phospholipids by these reactions and subsequent reactions that conduct to formation of ALEs and AGEs, have revealed changes in the molecular interactions and biophysical properties of these bilayers as consequence of these reactions. Then, more studies are desirable which could correlate the biophysics of modified phospholipids with metabolism in processes such as aging and diseases such as diabetes, atherosclerosis, and Alzheimer’s disease.
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Brea, Roberto J., Andrew K. Rudd, and Neal K. Devaraj. "Nonenzymatic biomimetic remodeling of phospholipids in synthetic liposomes." Proceedings of the National Academy of Sciences 113, no. 31 (July 20, 2016): 8589–94. http://dx.doi.org/10.1073/pnas.1605541113.
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Cell membranes have a vast repertoire of phospholipid species whose structures can be dynamically modified by enzymatic remodeling of acyl chains and polar head groups. Lipid remodeling plays important roles in membrane biology and dysregulation can lead to disease. Although there have been tremendous advances in creating artificial membranes to model the properties of native membranes, a major obstacle has been developing straightforward methods to mimic lipid membrane remodeling. Stable liposomes are typically kinetically trapped and are not prone to exchanging diacylphospholipids. Here, we show that reversible chemoselective reactions can be harnessed to achieve nonenzymatic spontaneous remodeling of phospholipids in synthetic membranes. Our approach relies on transthioesterification/acyl shift reactions that occur spontaneously and reversibly between tertiary amides and thioesters. We demonstrate exchange and remodeling of both lipid acyl chains and head groups. Using our synthetic model system we demonstrate the ability of spontaneous phospholipid remodeling to trigger changes in vesicle spatial organization, composition, and morphology as well as recruit proteins that can affect vesicle curvature. Membranes capable of chemically exchanging lipid fragments could be used to help further understand the specific roles of lipid structure remodeling in biological membranes.
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Alves, Ana Catarina, Daniela Ribeiro, Miguel Horta, José L. F. C. Lima, Cláudia Nunes, and Salette Reis. "A biophysical approach to daunorubicin interaction with model membranes: relevance for the drug's biological activity." Journal of The Royal Society Interface 14, no. 133 (August 2017): 20170408. http://dx.doi.org/10.1098/rsif.2017.0408.
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Daunorubicin is extensively used in chemotherapy for diverse types of cancer. Over the years, evidence has suggested that the mechanisms by which daunorubicin causes cytotoxic effects are also associated with interactions at the membrane level. The aim of the present work was to study the interplay between daunorubicin and mimetic membrane models composed of different ratios of 1,2-dimyristoyl- sn -glycero- 3 -phosphocholine (DMPC), sphingomyelin (SM) and cholesterol (Chol). Several biophysical parameters were assessed using liposomes as mimetic model membranes. Thereby, the ability of daunorubicin to partition into lipid bilayers, its apparent location within the membrane and its effect on membrane fluidity were investigated. The results showed that daunorubicin has higher affinity for lipid bilayers composed of DMPC, followed by DMPC : SM, DMPC : Chol and lastly by DMPC : SM : Chol. The addition of SM or Chol into DMPC membranes not only increases the complexity of the model membrane but also decreases its fluidity, which, in turn, reduces the amount of anticancer drug that can partition into these mimetic models. Fluorescence quenching studies suggest a broad distribution of the drug across the bilayer thickness, with a preferential location in the phospholipid tails. The gathered data support that daunorubicin permeates all types of membranes to different degrees, interacts with phospholipids through electrostatic and hydrophobic bonds and causes alterations in the biophysical properties of the bilayers, namely in membrane fluidity. In fact, a decrease in membrane fluidity can be observed in the acyl region of the phospholipids. Ultimately, such outcomes can be correlated with daunorubicin's biological action, where membrane structure and lipid composition have an important role. In fact, the results indicate that the intercalation of daunorubicin between the phospholipids can also take place in rigid domains, such as rafts that are known to be involved in different receptor processes, which are important for cellular function.
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Hatch, Grant M. "Cell biology of cardiac mitochondrial phospholipids." Biochemistry and Cell Biology 82, no. 1 (February 1, 2004): 99–112. http://dx.doi.org/10.1139/o03-074.
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Phospholipids are important structural and functional components of all biological membranes and define the compartmentation of organelles. Mitochondrial phospholipids comprise a significant proportion of the entire phospholipid content of most eukaroytic cells. In the heart, a tissue rich in mitochondria, the mitochondrial phospholipids provide for diverse roles in the regulation of various mitochondrial processes including apoptosis, electron transport, and mitochondrial lipid and protein import. It is well documented that alteration in the content and fatty acid composition of phospholipids within the heart is linked to alterations in myocardial electrical activity. In addition, reduction in the specific mitochondrial phospholipid cardiolipin is an underlying biochemical cause of Barth Syndrome, a rare and often fatal X-linked genetic disease that is associated with cardiomyopathy. Thus, maintenance of both the content and molecular composition of phospholipids synthesized within the mitochondria is essential for normal cardiac function. This review will focus on the function and regulation of the biosynthesis and resynthesis of mitochondrial phospholipids in the mammalian heart.Key words: phospholipid, metabolism, heart, cardiolipin, mitochondria.
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Wang, Bo, and Peter Tontonoz. "Phospholipid Remodeling in Physiology and Disease." Annual Review of Physiology 81, no. 1 (February 10, 2019): 165–88. http://dx.doi.org/10.1146/annurev-physiol-020518-114444.
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Phospholipids are major constituents of biological membranes. The fatty acyl chain composition of phospholipids determines the biophysical properties of membranes and thereby affects their impact on biological processes. The composition of fatty acyl chains is also actively regulated through a deacylation and reacylation pathway called Lands’ cycle. Recent studies of mouse genetic models have demonstrated that lysophosphatidylcholine acyltransferases (LPCATs), which catalyze the incorporation of fatty acyl chains into the sn-2 site of phosphatidylcholine, play important roles in pathophysiology. Two LPCAT family members, LPCAT1 and LPCAT3, have been particularly well studied. LPCAT1 is crucial for proper lung function due to its role in pulmonary surfactant biosynthesis. LPCAT3 maintains systemic lipid homeostasis by regulating lipid absorption in intestine, lipoprotein secretion, and de novo lipogenesis in liver. Mounting evidence also suggests that changes in LPCAT activity may be potentially involved in pathological conditions, including nonalcoholic fatty liver disease, atherosclerosis, viral infections, and cancer. Pharmacological manipulation of LPCAT activity and membrane phospholipid composition may provide new therapeutic options for these conditions.
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Flasiński, Michał, Katarzyna Hąc-Wydro, Paweł Wydro, and Patrycja Dynarowicz-Łątka. "Influence of platelet-activating factor, lyso-platelet-activating factor and edelfosine on Langmuir monolayers imitating plasma membranes of cell lines differing in susceptibility to anti-cancer treatment: the effect of plasmalogen level." Journal of The Royal Society Interface 11, no. 95 (June 6, 2014): 20131103. http://dx.doi.org/10.1098/rsif.2013.1103.
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Three structurally related but differing in biological activities single-chained ether phospholipids (PAF (platelet-activating factor) and lyso-PAF) and an anti-cancer drug (edelfosine (ED)) were investigated in Langmuir monolayers imitating natural membranes. The aim of the undertaken experiments was to study the influence of these lipids on monolayers mimicking plasma membranes of cell lines differing in susceptibility to the anti-cancer activity of ED, i.e. promyelocytic leukaemia cells (HL-60) and promyeloblastic leukaemia cells (K-562). As these cells differ essentially in the cholesterol/phospholipid ratio and plasmalogen concentration in the membrane, we have carried out systematic investigations in artificial systems of various compositions. The results for model leukaemia cell membrane were compared with data acquired for systems imitating normal leucocytes. Our results show that the level of plasmalogens significantly modulates the influence of the single-chained phospholipids on the investigated systems. The experiments confirmed also that the interactions of ether lipids with a model membrane of HL-60 cells (in biological tests sensitive to ED) have opposite character when compared with K-562, being resistant to ED. Moreover, the values of the parameters characterizing monolayers serving as membrane models (strength of interactions, monolayers fluidity and morphology) proved both sensitivity of these cells to ED and lack of their susceptibility towards PAF. Interestingly, it has been found that lyso-PAF, which is usually described as an inactive precursor of PAF, displays a stronger effect on HL-60 model membranes than ED.
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Gamsjaeger, Roland, Alexander Johs, Anna Gries, Hermann J. Gruber, Christoph Romanin, Ruth Prassl, and Peter Hinterdorfer. "Membrane binding of β2-glycoprotein I can be described by a two-state reaction model: an atomic force microscopy and surface plasmon resonance study." Biochemical Journal 389, no. 3 (July 26, 2005): 665–73. http://dx.doi.org/10.1042/bj20050156.
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Complexes formed between β2GPI (β2-glycoprotein I), a human plasma protein, and biological membranes are considered to be targets of macrophages and antiphospholipid autoantibodies involved in autoimmune diseases, such as antiphospholipid syndrome or systemic lupus erythematosus. The positively charged lysine-rich fifth domain of β2GPI facilitates its interaction with phospholipid membranes containing acidic phospholipids, which normally become exposed by apoptotic processes. In the present study, atomic force microscopy was applied to visualize the binding of β2GPI to a mixed phospholipid model membrane at physiological ionic strength. On supported lipid bilayers the formation of supramolecular assemblies of the protein with a height of approx. 3.3 nm was observed, suggesting a lateral agglomeration of β2GPI. Detailed analysis of kinetic constants using surface plasmon resonance revealed that the binding can be described by a two-state reaction model, i.e. a very fast interaction step, depending on the content of acidic phospholipids in the bilayer, and a second step with significantly lower kon and koff values. Taken together, our results suggest a biphasic interaction mechanism: a fast step of β2GPI binding to negatively charged lipids, mainly based on electrostatic interactions, and a slower phase of agglomeration of the protein on the bilayer surface accompanied by a protein-induced rigidification of the membrane, as revealed by electron paramagnetic resonance.
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Levi, Valeria, Ana M. Villamil Giraldo, Pablo R. Castello, Juan P. F. C. Rossi, and F. Luis González Flecha. "Effects of phosphatidylethanolamine glycation on lipid–protein interactions and membrane protein thermal stability." Biochemical Journal 416, no. 1 (October 28, 2008): 145–52. http://dx.doi.org/10.1042/bj20080618.
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Non-enzymatic glycation of biomolecules has been implicated in the pathophysiology of aging and diabetes. Among the potential targets for glycation are biological membranes, characterized by a complex organization of lipids and proteins interacting and forming domains of different size and stability. In the present study, we analyse the effects of glycation on the interactions between membrane proteins and lipids. The phospholipid affinity for the transmembrane surface of the PMCA (plasma-membrane Ca2+-ATPase) was determined after incubating the protein or the phospholipids with glucose. Results show that the affinity between PMCA and the surrounding phospholipids decreases significantly after phosphospholipid glycation, but remains unmodified after glycation of the protein. Furthermore, phosphatidylethanolamine glycation decreases by ∼30% the stability of PMCA against thermal denaturation, suggesting that glycated aminophospholipids induce a structural rearrangement in the protein that makes it more sensitive to thermal unfolding. We also verified that lipid glycation decreases the affinity of lipids for two other membrane proteins, suggesting that this effect might be common to membrane proteins. Extending these results to the in vivo situation, we can hypothesize that, under hyperglycaemic conditions, glycation of membrane lipids may cause a significant change in the structure and stability of membrane proteins, which may affect the normal functioning of membranes and therefore of cells.
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Munford, M. L., V. R. Lima, T. O. Vieira, G. Heinzelmann, T. B. Creczynski-Pasa, and A. A. Pasa. "AFM In-Situ Characterization of Supported Phospholipid Layers Formed by Vesicle Fusion." Microscopy and Microanalysis 11, S03 (December 2005): 90–93. http://dx.doi.org/10.1017/s1431927605050968.
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Atomic force microscopy (AFM) is a powerful tool for direct visualization of supported biological membranes [1]. Moreover, in-situ AFM measurements permit investigations of biological phenomena in real time and in physiological environments. In a previous work, we have studied the morphology and stability of supported phospholipid layers prepared by solution spreading (casting) on mica [2]. The images were acquired in the contact or contact-intermittent modes and the samples analyzed ex-situ just after solvent evaporation and after a hydration step, and in-situ with immersion in a buffer solution. Contact-mode imaging is less suitable for soft or weakly attached materials, since the tip can often scrape or drag the membranes during scanning, a disadvantage that can be overcome by applying intermittent methods. However, studies have also demonstrated that by adjusting the operative force it is possible to use contact-mode to obtain AFM images of soft phospholipids layers [3]. In the present work, we applied successfully in-situ AFM contact-mode to characterize phospholipid layers of 1,2-dimyristoyl-sn-glycero-3-phosphatitidylcholine (DMPC) and 1,2-dioleoyl-sn-glycero-3-phosphatidylcholine (DOPC), as well as a binary mixture of these phospholipids. The supported membranes were prepared on mica substrates by vesicle fusion method.
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KITO, Makoto. "Biochemical Studies on Multifunctions of Phospholipids in Biological Membranes." Journal of the agricultural chemical society of Japan 67, no. 7 (1993): 1047–53. http://dx.doi.org/10.1271/nogeikagaku1924.67.1047.
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Trapp, Marcus, Fanni Juranyi, Moeava Tehei, Lambert van Eijck, Bruno Demé, Thomas Gutberlet, and Judith Peters. "Elastic scattering studies of aligned DMPC multilayers on different hydrations1." Spectroscopy 24, no. 5 (2010): 461–66. http://dx.doi.org/10.1155/2010/361918.
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Biological membranes, consisting mainly of phospholipids and proteins, are organized in a bilayered structure which exhibits dynamical behaviour within time regimes ranging from 10–12s with the motion of alkyl chain defects and 1 s corresponding to collective excitations of the bilayer [Europhysics Letters8(1989), 201–206]. With the prominent role hydration plays on the structural phase behaviour of phospholipids membranes, it is essential for a better description of membranes to understand also the influence of hydration on the dynamics of membrane systems. In the present study we have performed neutron scattering investigations on highly oriented DMPC-d54 multilayers at two different relative humidity (rh) levels. Our results reveal the strong influence of hydration on the local membrane dynamics, i.e., head group dynamics.
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Rietveld, Annie, and Ben de Kruijff. "Phospholipids as a possible instrument for translocation of nascent proteins across biological membranes." Bioscience Reports 6, no. 9 (September 1, 1986): 775–82. http://dx.doi.org/10.1007/bf01117100.
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The interaction of phospholipids with precursor proteins, particularly with the mitochondrial precursor protein apocytochrome c is reviewed and integrated with other aspects of protein insertion and translocation, leading to a model for (apo)cytochrome c import into mitochondria, in which phospholipids play a dominant role.
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Alonso, Alicia, and Félix M. Goñi. "The Physical Properties of Ceramides in Membranes." Annual Review of Biophysics 47, no. 1 (May 20, 2018): 633–54. http://dx.doi.org/10.1146/annurev-biophys-070317-033309.
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Ceramides are sphingolipids containing a sphingosine or a related base, to which a fatty acid is linked through an amide bond. When incorporated into a lipid bilayer, ceramides exhibit a number of properties not shared by almost any other membrane lipid: Ceramides ( a) are extremely hydrophobic and thus cannot exist in suspension in aqueous media; ( b) increase the molecular order (rigidity) of phospholipids in membranes; ( c) give rise to lateral phase separation and domain formation in phospholipid bilayers; ( d) possess a marked intrinsic negative curvature that facilitates formation of inverted hexagonal phases; ( e) make bilayers and cell membranes permeable to small and large (i.e., protein-size) solutes; and ( f) promote transmembrane (flip-flop) lipid motion. Unfortunately, there is hardly any link between the physical studies reviewed here and the mass of biological and clinical studies on the effects of ceramides in health and disease.
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Morita, Shin-ya, Tokuji Tsuji, and Tomohiro Terada. "Protocols for Enzymatic Fluorometric Assays to Quantify Phospholipid Classes." International Journal of Molecular Sciences 21, no. 3 (February 4, 2020): 1032. http://dx.doi.org/10.3390/ijms21031032.
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Phospholipids, consisting of a hydrophilic head group and two hydrophobic acyl chains, are essential for the structures of cell membranes, plasma lipoproteins, biliary mixed micelles, pulmonary surfactants, and extracellular vesicles. Beyond their structural roles, phospholipids have important roles in numerous biological processes. Thus, abnormalities in the metabolism and transport of phospholipids are involved in many diseases, including dyslipidemia, atherosclerosis, cholestasis, drug-induced liver injury, neurological diseases, autoimmune diseases, respiratory diseases, myopathies, and cancers. To further clarify the physiological, pathological, and molecular mechanisms and to identify disease biomarkers, we have recently developed enzymatic fluorometric assays for quantifying all major phospholipid classes, phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, phosphatidic acid, phosphatidylinositol, phosphatidylglycerol + cardiolipin, and sphingomyelin. These assays are specific, sensitive, simple, and high-throughput, and will be applicable to cells, intracellular organelles, tissues, fluids, lipoproteins, and extracellular vesicles. In this review, we present the detailed protocols for the enzymatic fluorometric measurements of phospholipid classes in cultured cells.
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Coulombe, P. A., and M. Bendayan. "Cytochemical demonstration of increased phospholipid content in cell membranes in chlorphentermine-induced phospholipidosis." Journal of Histochemistry & Cytochemistry 37, no. 2 (February 1989): 139–47. http://dx.doi.org/10.1177/37.2.2911004.
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We recently introduced a novel cytochemical approach to high-resolution cytochemistry of phospholipids in biological tissues. The technique consists of adsorption of bee venom phospholipase A2 to colloidal gold particles (PLA2-gold complex) and subsequent application of this complex for localization of the enzyme substrate, i.e., glycerophospholipids. In the present study, this technique was applied at the post-embedding level, in both light (LM) and transmission electron microscopy (TEM), to investigate drug-induced phospholipidosis, an experimental disorder in which the lysosomal catabolism of phospholipids is inhibited. Rats received one week of daily treatment (40 mg IP/kg) with chlorphentermine (CP), a cationic amphiphilic drug known to induce phospholipidosis in several tissues. Glutaraldehyde- and osmium-fixed lung and kidney tissues from both treated and control animals, were embedded in Epon and sections processed for labeling by PLA2-gold. In CP-treated specimens the presence of large osmiophilic inclusions in several cell types of lung parenchyma and kidney cortex confirmed the onset of phospholipidosis. These inclusions were densely labeled by PLA2-gold at both LM and TEM levels. Two general types of abnormal inclusions were distinguished on the basis of their ultrastructure and labeling pattern by PLA2-gold, suggesting different content or configuration of phospholipids. Moreover, quantitative evaluation of labeling density over various membrane compartments in lung alveolar cells evidenced significantly increased phospholipid content after CP treatment. In type II pneumocytes, such increases were measured in membranes of the RER, Golgi complex, outer and inner nuclear envelope, and the basolateral and apical domains of the plasma membrane. In capillary endothelial cells, the basal and luminal domains of the plasma membrane also showed an increase in labeling density. These results further demonstrate the potential usefulness of the PLA2-gold technique for in situ ultrastructural localization of phospholipids in normal and pathological tissues.
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Bloom, Myer, and Ole G. Mouritsen. "The evolution of membranes." Canadian Journal of Chemistry 66, no. 4 (April 1, 1988): 706–12. http://dx.doi.org/10.1139/v88-123.
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Consideration of the influence of cholesterol on the physical properties of biological membranes leads to the conclusion that cholesterol increases the thickness of fluid membrane bilayers without appreciably increasing the microviscosity component of membrane fluidity. At sufficiently high cholesterol concentrations, the gel–liquid crystalline phase transition is completely eliminated in phospholipids–cholesterol mixtures and the system has the properties of a two-dimensional liquid over a wide range of temperatures. It is proposed that with the evolution of cholesterol and related sterols in an oxygen-rich atmosphere, the resulting modification of physical constraints on membrane properties made it possible for new evolutionary driving forces to manifest themselves leading to the peculiar properties of plasma membranes of eucaryotic cells.
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Poccia, Dominic, and Banafshé Larijani. "Phosphatidylinositol metabolism and membrane fusion." Biochemical Journal 418, no. 2 (February 11, 2009): 233–46. http://dx.doi.org/10.1042/bj20082105.
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Membrane fusion underlies many cellular events, including secretion, exocytosis, endocytosis, organelle reconstitution, transport from endoplasmic reticulum to Golgi and nuclear envelope formation. A large number of investigations into membrane fusion indicate various roles for individual members of the phosphoinositide class of membrane lipids. We first review the phosphoinositides as membrane recognition sites and their regulatory functions in membrane fusion. We then consider how modulation of phosphoinositides and their products may affect the structure and dynamics of natural membranes facilitating fusion. These diverse roles underscore the importance of these phospholipids in the fusion of biological membranes.
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Ramos-Martín, Francisco, Claudia Herrera-León, Viviane Antonietti, Pascal Sonnet, Catherine Sarazin, and Nicola D’Amelio. "Antimicrobial Peptide K11 Selectively Recognizes Bacterial Biomimetic Membranes and Acts by Twisting Their Bilayers." Pharmaceuticals 14, no. 1 (December 22, 2020): 1. http://dx.doi.org/10.3390/ph14010001.
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K11 is a synthetic peptide originating from the introduction of a lysine residue in position 11 within the sequence of a rationally designed antibacterial scaffold. Despite its remarkable antibacterial properties towards many ESKAPE bacteria and its optimal therapeutic index (320), a detailed description of its mechanism of action is missing. As most antimicrobial peptides act by destabilizing the membranes of the target organisms, we investigated the interaction of K11 with biomimetic membranes of various phospholipid compositions by liquid and solid-state NMR. Our data show that K11 can selectively destabilize bacterial biomimetic membranes and torque the surface of their bilayers. The same is observed for membranes containing other negatively charged phospholipids which might suggest additional biological activities. Molecular dynamic simulations reveal that K11 can penetrate the membrane in four steps: after binding to phosphate groups by means of the lysine residue at the N-terminus (anchoring), three couples of lysine residues act subsequently to exert a torque in the membrane (twisting) which allows the insertion of aromatic side chains at both termini (insertion) eventually leading to the flip of the amphipathic helix inside the bilayer core (helix flip and internalization).
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Cyr, Normand, Terry K. Smith, Élodie Boisselier, Louis-Philippe Leroux, Anwar Hasil Kottarampatel, Amanda Davidsen, Christian Salesse, and Armando Jardim. "The hydrophobic region of the Leishmania peroxin 14: requirements for association with a glycosome mimetic membrane." Biochemical Journal 475, no. 2 (January 31, 2018): 511–29. http://dx.doi.org/10.1042/bcj20170746.
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Protein import into the Leishmania glycosome requires docking of the cargo-loaded peroxin 5 (PEX5) receptor to the peroxin 14 (PEX14) bound to the glycosome surface. To examine the LdPEX14–membrane interaction, we purified L. donovani promastigote glycosomes and determined the phospholipid and fatty acid composition. These membranes contained predominately phosphatidylethanolamine, phosphatidylcholine, and phosphatidylglycerol (PG) modified primarily with C18 and C22 unsaturated fatty acid. Using large unilamellar vesicles (LUVs) with a lipid composition mimicking the glycosomal membrane in combination with sucrose density centrifugation and fluorescence-activated cell sorting technique, we established that the LdPEX14 membrane-binding activity was dependent on a predicted transmembrane helix found within residues 149–179. Monolayer experiments showed that the incorporation of PG and phospholipids with unsaturated fatty acids, which increase membrane fluidity and favor a liquid expanded phase, facilitated the penetration of LdPEX14 into biological membranes. Moreover, we demonstrated that the binding of LdPEX5 receptor or LdPEX5–PTS1 receptor–cargo complex was contingent on the presence of LdPEX14 at the surface of LUVs.
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Fiore, Michele, and René Buchet. "Symmetry Breaking of Phospholipids." Symmetry 12, no. 9 (September 10, 2020): 1488. http://dx.doi.org/10.3390/sym12091488.
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Either stereo reactants or stereo catalysis from achiral or chiral molecules are a prerequisite to obtain pure enantiomeric lipid derivatives. We reviewed a few plausibly organic syntheses of phospholipids under prebiotic conditions with special attention paid to the starting materials as pro-chiral dihydroxyacetone and dihydroxyacetone phosphate (DHAP), which are the key molecules to break symmetry in phospholipids. The advantages of homochiral membranes compared to those of heterochiral membranes were analysed in terms of specific recognition, optimal functions of enzymes, membrane fluidity and topological packing. All biological membranes contain enantiomerically pure lipids in modern bacteria, eukarya and archaea. The contemporary archaea, comprising of methanogens, halobacteria and thermoacidophiles, are living under extreme conditions reminiscent of primitive environment and may indicate the origin of one ancient evolution path of lipid biosynthesis. The analysis of the known lipid metabolism reveals that all modern cells including archaea synthetize enantiomerically pure lipid precursors from prochiral DHAP. Sn-glycerol-1-phosphate dehydrogenase (G1PDH), usually found in archaea, catalyses the formation of sn-glycerol-1-phosphate (G1P), while sn-glycerol-3-phosphate dehydrogenase (G3PDH) catalyses the formation of sn-glycerol-3-phosphate (G3P) in bacteria and eukarya. The selective enzymatic activity seems to be the main strategy that evolution retained to obtain enantiomerically pure lipids. The occurrence of two genes encoding for G1PDH and G3PDH served to build up an evolutionary tree being the basis of our hypothesis article focusing on the evolution of these two genes. Gene encoding for G3PDH in eukarya may originate from G3PDH gene found in rare archaea indicating that archaea appeared earlier in the evolutionary tree than eukarya. Archaea and bacteria evolved probably separately, due to their distinct respective genes coding for G1PDH and G3PDH. We propose that prochiral DHAP is an essential molecule since it provides a convergent link between G1DPH and G3PDH. The synthesis of enantiopure phospholipids from DHAP appeared probably firstly in the presence of chemical catalysts, before being catalysed by enzymes which were the products of later Darwinian selection. The enzymes were probably selected for their efficient catalytic activities during evolution from large libraries of vesicles containing amino acids, carbohydrates, nucleic acids, lipids, and meteorite components that induced symmetry imbalance.
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Henriques, Sónia Troeira, Yen-Hua Huang, K. Johan Rosengren, Henri G. Franquelim, Filomena A. Carvalho, Adam Johnson, Secondo Sonza, et al. "Decoding the Membrane Activity of the Cyclotide Kalata B1." Journal of Biological Chemistry 286, no. 27 (May 16, 2011): 24231–41. http://dx.doi.org/10.1074/jbc.m111.253393.
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Cyclotides, a large family of cyclic peptides from plants, have a broad range of biological activities, including insecticidal, cytotoxic, and anti-HIV activities. In all of these activities, cell membranes seem likely to be the primary target for cyclotides. However, the mechanistic role of lipid membranes in the activity of cyclotides remains unclear. To determine the role of lipid organization in the activity of the prototypic cyclotide, kalata B1 (kB1), and synthetic analogs, their bioactivities and affinities for model membranes were evaluated. We found that the bioactivity of kB1 is dependent on the lipid composition of target cell membranes. In particular, the activity of kB1 requires specific interactions with phospholipids containing phosphatidylethanolamine (PE) headgroups but is further modulated by nonspecific peptide-lipid hydrophobic interactions, which are favored in raft-like membranes. Negatively charged phospholipids do not favor high kB1 affinity. This lipid selectivity explains trends in antimicrobial and hemolytic activities of kB1; it does not target bacterial cell walls, which are negatively charged and lacking PE-phospholipids but can insert in the membranes of red blood cells, which have a low PE content and raft domains in their outer layer. We further show that the anti-HIV activity of kB1 is the result of its ability to target and disrupt the membranes of HIV particles, which are raft-like membranes very rich in PE-phospholipids.
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Doberstein, SK, and TD Pollard. "Localization and specificity of the phospholipid and actin binding sites on the tail of Acanthamoeba myosin IC." Journal of Cell Biology 117, no. 6 (June 15, 1992): 1241–49. http://dx.doi.org/10.1083/jcb.117.6.1241.
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We used bacterially expressed beta-galactosidase fusion proteins to localize the phospholipid binding domain of Acanthamoeba myosin IC to the region between amino acids 701 and 888 in the NH2-terminal half of the tail. Using a novel immobilized ligand lipid binding assay, we determined that myosin I can bind to several different acidic phospholipids, and that binding requires a minimum of 5 mol% acidic phospholipid in a neutral lipid background. The presence of di- and triglycerides and sterols in the lipid bilayer do not contribute to the affinity of myosin I for membranes. We confirm that the ATP-insensitive actin binding site is contained in the COOH-terminal 30 kD of the tail as previously shown for Acanthamoeba myosin IA. We conclude that the association of the myosin IC tail with acidic phospholipid head groups supplies much of the energy for binding myosin I to biological membranes, but probably not specificity for targeting myosin I isoforms to different cellular locations.
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Tanfani, F., E. Kossowska, J. Purzycka-Preis, M. M. Zydowo, M. Wozniak, E. Tartaglini, and E. Bertoli. "The interaction of phospholipid bilayers with pig heart AMP deaminase: Fourier-transform infrared spectroscopic and kinetic studies." Biochemical Journal 291, no. 3 (May 1, 1993): 921–26. http://dx.doi.org/10.1042/bj2910921.
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The interaction of pig heart AMP deaminase with different chemical species of phosphatidylcholine and with natural plasma membranes has been investigated. Phospholipids added to the system either as natural biological membranes (plasma membrane vesicles) or in the form of liposomes containing unsaturated phosphatidylcholine considerably enhanced AMP deaminase activity. The secondary structure of pig heart AMP deaminase in the absence and in the presence of dioleoyl phosphatidylcholine and dipalmitoyl phosphatidylcholine liposomes was investigated by Fourier-transform infrared spectroscopy. Quantitative analysis of the amide I band showed that the enzyme contains 45% beta-sheets, 28% alpha-helix, 16% turns and 11% non-ordered structure. In the presence of dioleoyl phosphatidylcholine liposomes, the beta/alpha content ratio decreased; this decrease was dependent on the amount of lipid added. This phenomenon was not observed in the case of dipalmitoyl phosphatidylcholine liposomes. These data suggest a possible role for membrane phospholipids in the regulation of AMP deaminase activity.
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Fischer, Torsten, Ivan I. Senin, Pavel P. Philippov, and Karl-Wilhelm Koch. "Application of Different Lipid Surfaces to Monitor Protein–Membrane Interactions by Surface Plasmon Resonance Spectroscopy." Spectroscopy 16, no. 3-4 (2002): 271–79. http://dx.doi.org/10.1155/2002/630549.
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Planar lipid bilayers on sensor chip surfaces have become useful tools to study membrane bound processes by surface plasmon resonance spectroscopy. We immobilized phospholipids on sensor chips by different approaches. First, a self-assembled monolayer of octadecylmercaptan was formed on a blank gold surface and subsequent addition of phospholipids led to formation of a heterobilayer. Second, a self-assembled monolayer of mercaptoundecanoic acid was formed on a gold surface, the carboxy groups of mercaptoundecanoic acid were activated and covalently linked to phosphatidylethanolamine. Addition of phospholipids then led to a bilayer with phosphatidylethanolamine as the lower leaflet. Third, a hydrophobic sensor chip (L1, BIAcore) was used as a binding matrix for phospholipids. These lipid surfaces were tested, whether they are suitable to study proteinamembrane interactions. As biological test system we used the Ca2+-myristoyl-switch of the neuronal Ca2+-binding protein recoverin. All three surfaces were sufficiently stable to monitor the Ca2+-dependent binding of recoverin to membranes.
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WANG, Shao-Xiong, Yu-Tong SUN, and Sen-Fang SUI. "Membrane-induced conformational change in human apolipoprotein H." Biochemical Journal 348, no. 1 (May 9, 2000): 103–6. http://dx.doi.org/10.1042/bj3480103.
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The interaction of apolipoprotein H (Apo H) with lipid membrane has been considered to be a basic mechanism for the biological function of the protein. Previous reports have demonstrated that Apo H can interact only with membranes containing anionic phospholipids. Here we study the membrane-induced conformational change of Apo H by CD spectroscopy with two different model systems: anionic-phospholipid-containing liposomes [such as 1,2-dimyristoyl-sn-glycero-3-phosphoglycerol (DMPG) and cardiolipin], and the water/methanol mixtures at moderately low pH, which mimic the micro-physicochemical environment near the membrane surface. It is found that Apo H undergoes a remarkable conformational change on interaction with liposomes containing anionic phospholipid. To interact with liposomes containing DMPG, there is a 6.8% increase in α-helix in the secondary structures; in liposomes containing cardiolipin, however, there is a 12.6% increase in α-helix and a 9% decrease in β-sheet. The similar conformation change in Apo H can be induced by treatment with an appropriate mixture of water/methanol. The results indicate that the association of Apo H with membrane is correlated with a certain conformational change in the secondary structure of the protein.
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Taraschi, TF, A. Parashar, M. Hooks, and H. Rubin. "Perturbation of red cell membrane structure during intracellular maturation of Plasmodium falciparum." Science 232, no. 4746 (April 4, 1986): 102–4. http://dx.doi.org/10.1126/science.3006251.
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An experimental approach, which in this study was applied to the malarial system, can be used to analyze the molecular structure and organization of individual phospholipids in a wide variety of biological membranes. Electron spin resonance spectroscopy was used to investigate the structural modifications of the major red cell phospholipids that occur in erythrocyte membranes infected with the human malarial parasite, Plasmodium falciparum. These modifications were correlated with the intracellular developmental stage of the parasite. Phosphatidylcholine, phosphatidylethanolamine, and phosphatidylserine were increasingly disordered (fluidized) as infection progressed. This disordering occurred at different rates and to varying extents.
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Naik, Jyoti, Dirk R. de Waart, Karina Utsunomiya, Suzanne Duijst, Kam Ho Mok, Ronald P. J. Oude Elferink, Piter J. Bosma, and Coen C. Paulusma. "ATP8B1 and ATP11C: Two Lipid Flippases Important for Hepatocyte Function." Digestive Diseases 33, no. 3 (2015): 314–18. http://dx.doi.org/10.1159/000371665.
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P4 ATPases are lipid flippases and transport phospholipids from the exoplasmic to the cytosolic leaflet of biological membranes. Lipid flipping is important for the biogenesis of transport vesicles. Recently it was shown that loss of the P4 ATPases ATP8B1 and ATP11C are associated with severe Cholestatic liver disease. Mutation of ATP8B1 cause progressive familial Intrahepatic Cholestasis type 1 (PFIC1)and benign recurrent intrahepatic cholestasis type 1 (BRIC 1). From our observations we hypothesized that ATP8B1 deficiency causes a phospholipids randomization at the canalicular membrane, which results in extraction of cholesterol due to increase sensitivity of the canalicular membrane. Deficiency of ATP11C causes conjugated hyperbilirubinemia. In our preliminary result we observed accumulation of unconjugated bile salts in Atp11c deficient mice probably because of regulation in the expression or function of OATP1B2. Similar to ATP8B1, ATP11C have regulation on membrane transporters.
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Matos, Anna Lívia Linard, Sergej Kudruk, Johanna Moratz, Milena Heflik, David Grill, Bart Jan Ravoo, and Volker Gerke. "Membrane Binding Promotes Annexin A2 Oligomerization." Cells 9, no. 5 (May 8, 2020): 1169. http://dx.doi.org/10.3390/cells9051169.
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Annexin A2 (AnxA2) is a cytosolic Ca2+ regulated membrane binding protein that can induce lipid domain formation and plays a role in exocytosis and endocytosis. To better understand the mode of annexin-membrane interaction, we analyzed membrane-bound AnxA2 assemblies by employing a novel 3-armed chemical crosslinker and specific AnxA2 mutant proteins. Our data show that AnxA2 forms crosslinkable oligomers upon binding to membranes containing negatively charged phospholipids. AnxA2 mutants with amino acid substitutions in residues predicted to be involved in lateral protein–protein interaction show compromised oligomer formation, albeit still being capable of binding to negatively charged membranes in the presence of Ca2+. These results suggest that lateral protein–protein interactions are involved in the formation of AnxA2 clusters on a biological membrane.
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Świerczek-Zięba, G., J. Lodowska, U. Mazurek, S. Kurkiewicz, and T. Wilczok. "METOPROLOL EFFECT ON FATTY ACIDS COMPOSITION OF CELL MEMBRANE PHOSPHOLIPIDS." Scientia Pharmaceutica 69, no. 2 (June 30, 2001): 167–78. http://dx.doi.org/10.3797/scipharm.aut-01-18.
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It is quite well known that β-blockers influence the stability of cell membranes, but the effect of metoprolol on the composition of cell membrane lipids is not established. On the other hand, synchronous culture of Chlorella vulgaris cells, which consists of cells brought to the same developmental stage by cycling lighting, provides a convenient biological model in unidirectional analyses aimed at assessment of effects of xenobiotics on cells. Advantages of the model include short life cycle and possibility to control metabolic processes of the cells across the broad range. We assessed the effect of metoprolol on fatty acids composition of cell membrane phospholipids in consecutive life cycle stages of Chlorella vulgaris. Lipids were extracted using a chlorofonn/methanol method. Phospholipids were precipitated from the chloroform phase with cold acetone and following centrifugation the pellet of phospholipids was hydrolyzed in alkaline solution. Fatty acids were extracted with petroleum ether and then methylated with BF3-methanol. This protocol produced methyl esters of fatty acids which were subjected to GC-MS analysis. Metoprolol had no effect on the number of progeny cells of Chlorella vulgaris throughout their life cycle at the concentration range tested (5x10-5 M, 5x10-6 M, 5x10-7 M). However, we observed stimulation of biological activity of Chlorclla cells as measured by spectrophotomctry at λ=680 nm. Metoprolol, at the highest concentration, increased phospholipids content in mother cells. Simultaneously, relative amount and saturation level of thc fatty acids remained constant.
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Stoll, Ulrich. "Fatty acid exchange of phospholipids in membranes of rat heart." L’Année Biologique 38, no. 1 (January 1999): 17–26. http://dx.doi.org/10.1016/s0003-5017(99)80006-3.
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Lubenets, V. I., V. V. Havryliak, A. Z. Pylypets, and A. V. Nakonechna. "Changes in the spectrum of proteins and phospholipids in tissues of rats exposed to thiosulfonates." Regulatory Mechanisms in Biosystems 9, no. 4 (November 14, 2018): 495–500. http://dx.doi.org/10.15421/021874.
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Esters of thiosulfoacids demonstrate a wide range of biological activity. One of their effects is the influence on the metabolism of proteins and lipids in the body. Therefore, the purpose of our experiment was to study the impact of synthesized thiosulfonates on the total content of proteins and phospholipids, as well as their spectrum in the blood, liver, and kidney of rats. For the experiment, allyl, ethyl, and methyl esters of thiosulfoacid were used. The protein profile of rat tissues was investigated by electrophoresis, and the ratio of different fractions of phospholipids by thin-layer chromatography. Our results have shown that short-term administration of thiosulfonates in a dose of 300 mg/kg of body weight did not cause significant changes in the content of total protein and its fractions in liver tissue, whereas the effect of allyl and ethyl esters of thiosulfoacid was accompanied by an increase in the total protein and albumin in the blood plasma. The decrease in total protein was found in the kidney tissue of rats injected with allyl- and methyl thiosulfonates. The newly synthesized compounds did not lead to significant changes in the total content of phospholipids in blood plasma and tissues of rats, except for methyl thiosulfonate, the effect of which was accompanied by an increase in the total phospholipids in the liver of rats. These data may indicate an adaptive reaction of the rat’s organism. Tissue-specific features of the phospholipid spectrum were detected in rats after short-term exposure to thiosulfonates. The most significant effect on the phospholipid profile in the blood was shown for allyl- and ethyl esters of thiosulfoacid. Their action was accompanied by a decrease in the phosphatidylserine and phosphatidylinositol fractions, while phosphatidylethanolamine and phosphatidylcholine increased, respectively. Esters of thiosulfoacid significantly influenced the ratio of different fractions of phospholipids in the liver and kidney tissues. The phospholipid composition of the liver was more influenced by the allyl and methyl esters of thiosulfoacid, whereas for the kidney tissue a greater effect was observed for ethyl and methyl esters. Thus, the action of allyl ester of thiosulfoacid caused a decrease in the asymmetry coefficient of hepatocyte membranes, indicating an elevation of the lipid bilayer saturation and the increase of membrane microviscosity. Similar changes were found in the kidney of rats treated with allyl- and ethyl thiosulfonates.
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Kang, Louis, and Tom C. Lubensky. "Chiral twist drives raft formation and organization in membranes composed of rod-like particles." Proceedings of the National Academy of Sciences 114, no. 1 (December 20, 2016): E19—E27. http://dx.doi.org/10.1073/pnas.1613732114.
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Lipid rafts are hypothesized to facilitate protein interaction, tension regulation, and trafficking in biological membranes, but the mechanisms responsible for their formation and maintenance are not clear. Insights into many other condensed matter phenomena have come from colloidal systems, whose micron-scale particles mimic basic properties of atoms and molecules but permit dynamic visualization with single-particle resolution. Recently, experiments showed that bidisperse mixtures of filamentous viruses can self-assemble into colloidal monolayers with thermodynamically stable rafts exhibiting chiral structure and repulsive interactions. We quantitatively explain these observations by modeling the membrane particles as chiral liquid crystals. Chiral twist promotes the formation of finite-sized rafts and mediates a repulsion that distributes them evenly throughout the membrane. Although this system is composed of filamentous viruses whose aggregation is entropically driven by dextran depletants instead of phospholipids and cholesterol with prominent electrostatic interactions, colloidal and biological membranes share many of the same physical symmetries. Chiral twist can contribute to the behavior of both systems and may account for certain stereospecific effects observed in molecular membranes.
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WIERZCHOLSKI, Krzysztof. "JOINT CARTILAGE LUBRICATION WITH PHOSPHOLIPID BILAYER." Tribologia 266, no. 2 (April 30, 2016): 145–57. http://dx.doi.org/10.5604/01.3001.0010.7573.
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The surface of an articular cartilage human joint, coated with phospholipid bilayers or multi-layers, plays an important role in the surface-active phospholipid lubrication, friction, and wear during human limb movement. The biological bi-layer is a thin polar membrane composed of two layers of phospholipids that have a hydrophilic phosphate head (from the outside) and a hydrophobic tail (from the inside) consisting of two fatty acid chains. These membranes are flat sheets that form a continuous barrier around all cells. Synovial fluid (SF) in the human joint gap contains glycoprotein, lubricin (proteinglycan 4), and hyaluronidase, i.e. an enzyme that produces hialuron acid and ±10% phospholipids. Because the mechanism of surface articular phospholipid lubrication (SAPL) has been a frequently controversial subject in the past decade, this fact requires showing the hydrodynamic description in the form of a mathematical model of the abovementioned problem and its particular solution. To give a description of this model, it is necessary to recognize the variations of the dynamic viscosity of synovial fluid as a function of parameters depending on the presence of many phospholipid particles. To these parameters belong power (exponent) concentration of hydrogen ions (pH), cartilage wet ability (We), collagen fibre concentration in synovial fluid, and a created electrostatic field on the phospholipid membrane. Based on the Young-Laplace-Kelvin Law, initial achievements presented in scientific papers and our own investigations illustrated in this paper, the decrements, and increments of synovial fluid dynamic viscosities versus pH and wet ability (We) increases, simultaneously taking into account the influence of the intensity of charges in the electrostatic field. Moreover, this study considers the influence of collagen fibre concentration on the dynamic viscosity of synovial fluid. Based on initial considerations performed by virtue of the developed SAPL, it may be stated that the charge increments from low to high values of the electrostatic field is connected with viscosity increases of synovial fluid but only simultaneously with the pH index and cartilage wet ability variations.
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Zhangabylov, Abay, Bakytzhan Bimbetov, Nurlan Jainakbayev, and Каramyat Zordinova. "Current view of the yesterday's medicine (review)." Journal "Medicine" 9-10, no. 219-220 (January 20, 2021): 44–51. http://dx.doi.org/10.31082/1728-452x-2020-219-2220-9-10-44-51.
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Phospholipids (PL) – lipids that are not involved in accumulation of fatty deposits play a significant role and serve various functions. Firstly, as a component of cell membranes of all cells in the organism. In clinical practice, for the past decades, phospholipids were primarily used as hepaprotective substances, going by the name of “essential phospholipids (EPL)”. Becoming a popular, demanded, well-promoted remedy for the treatment of liver diseases. However, despite the many years of approbation, the existing and sufficientclinicalexperience, discussions regarding their benefits, effectiveness, safety and reliability are still underway and have brought up diametrically opposed views. From complete rejection of EPL as medicinal means, to full recognition of the advertised properties of EPL drugs based on the given manufacturer’s descriptions. For this reason, to clarify the issuing situation, we have conducted a literature search on the object of investigation. Purpose of the study. Search and critical analysis of modern literature sources on the topic of work using the principles of evidence-based medicine. Material and Methods. A critical online review of the literature sources chosen for the research has been carried out in the Web of Science Thompson Reuters, Springer Link and Pubmed databases, as well as in research works and online articles 10 years deep. Inclusion criteria: research papers with a high index of evidence base. Exclusion criteria: literature sources with no evidence, low quality works. Results and Discussion. The articleoutlines the natural role of proteins, lipids and the function of the cytolemma of intracellularorganoids in the restoration of damaged membranes of hepatocytes - de novo. Substantiating the obvious uselessness of using essential phospholipids in the treatment of liver diseases in general, fatty hepatosis in particular. The inability of penetration into liver cells for phospholipids in their native form and their alignment in thehepacyte membrane is indicated, since they belong to different biological species and have a mutually closed genetic system. In the literature search undertaken by us on this issue, the analytical and critical review of scientific literature have also shown that when ingested, essential phospholipids have low bioavailability, as the phospholipids in the chylomicrons do not directly enter the liver, but first the lymphatic system through which they are transported to the adipose tissue of the organism, where they are accumulated and metabolized. With parenteral administration, EPL spreading through the bloodstream can accumulate in other organs, systems, without reaching the liver tissue. For example, the largest amounts of EPL are usually found in the cell membranes of the nervous tissue and the brain. Conclusion. Essential phospholipids in the form of soy lecithin products cannot replace the endogenous phospholipids of the human body - in principle. Keywords: essentialphospholipids, liver cell membranes, hepaprotectors.
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Hon, Gloudina, Mogamat Hassan, Susan Janse van Rensburg, Stefan Abel, De Wet Marais, Paul van Jaarsveld, Cornelius Smuts, Franclo Henning, Rajiv Erasmus, and Tandi Matsha. "Immune cell membrane fatty acids and inflammatory marker, C-reactive protein, in patients with multiple sclerosis." British Journal of Nutrition 102, no. 9 (May 19, 2009): 1334–40. http://dx.doi.org/10.1017/s0007114509382185.
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Measurement of fatty acids in biological fluids and cell membranes including leucocytes from multiple sclerosis patients is inconsistent. The objective of the present study was to investigate the fatty acid composition within the different membrane phospholipid fractions in peripheral blood mononuclear cells in multiple sclerosis patients, and correlate with severity of neurological outcome as measured by the Kurtzke Expanded Disability Status Scale and Functional System Scores. The fatty acid composition of phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, sphingomyelin and phosphatidylinositol phospholipids in the peripheral blood mononuclear cells of twenty-six multiple sclerosis and twenty-five control subjects were measured by GC, and C-reactive protein was measured in all subjects. The elongation product of 20 : 4n-6, 22 : 4n-6, was significantly decreased in membrane phosphatidylethanolamine and phosphatidylserine in multiple sclerosis patients (P = 0·01 and P = 0·03 respectively), and correlated inversely with severity of disease and C-reactive protein. Also an inverse correlation was observed between the C-reactive protein and membrane phosphatidylcholine and phosphatidylserine 20 : 4n-6. Cultural and ethnic differences, as well as dietary variability, especially in a diseased state have been implicated in the differences observed in the fatty acid composition in peripheral blood mononuclear cell membranes of patients with multiple sclerosis. The present results suggest that the disease state may in part explain the reported inconsistencies in fatty acid levels in multiple sclerosis patients.
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Vogel, Alexander, Jörg Nikolaus, Katrin Weise, Gemma Triola, Herbert Waldmann, Roland Winter, Andreas Herrmann, and Daniel Huster. "Interaction of the human N-Ras protein with lipid raft model membranes of varying degrees of complexity." Biological Chemistry 395, no. 7-8 (July 1, 2014): 779–89. http://dx.doi.org/10.1515/hsz-2013-0294.
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Abstract Ternary lipid mixtures composed of cholesterol, saturated (frequently with sphingosine backbone), and unsaturated phospholipids show stable phase separation and are often used as model systems of lipid rafts. Yet, their ability to reproduce raft properties and function is still debated. We investigated the properties and functional aspects of three lipid raft model systems of varying degrees of biological relevance – PSM/POPC/Chol, DPPC/POPC/Chol, and DPPC/DOPC/Chol – using 2H solid-state nuclear magnetic resonance (NMR) spectroscopy, fluorescence microscopy, and atomic force microscopy. While some minor differences were observed, the general behavior and properties of all three model mixtures were similar to previously investigated influenza envelope lipid membranes, which closely mimic the lipid composition of biological membranes. For the investigation of the functional aspects, we employed the human N-Ras protein, which is posttranslationally modified by two lipid modifications that anchor the protein to the membrane. It was previously shown that N-Ras preferentially resides in liquid-disordered domains and exhibits a time-dependent accumulation in the domain boundaries of influenza envelope lipid membranes. For all three model mixtures, we observed the same membrane partitioning behavior for N-Ras. Therefore, we conclude that even relatively simple models of raft membranes are able to reproduce many of their specific properties and functions.
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Huang, Yuchao, Yichang Liu, Yayu Chen, Meiru Song, Mingdong Huang, Jinping Xue, Lin Liu, and Jinyu Li. "Probing the interactions of phthalocyanine-based photosensitizers with model phospholipid bilayer by molecular dynamics simulations." Journal of Porphyrins and Phthalocyanines 22, no. 09n10 (August 21, 2018): 764–70. http://dx.doi.org/10.1142/s1088424618500566.
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Phthalocyanines (Pc) have received considerable attention in the design of photosensitizers for photodynamic therapy (PDT). It is of great interest to design novel Pc-based photosensitizer with improved biological efficiency, which largely relies on the understanding of the interactions of Pc with cell membranes at a molecular level. Here, via all-atom molecular dynamics simulations, we explored the interaction mechanism between a model phospholipid bilayer and three zinc Pc (ZnPc) molecules with different hydrophobicity in nature. We find that the adsorption and insertion behaviors of ZnPc molecules in the model bilayer are different due to the differing hydrophobicity and interaction patterns with phospholipids. Moreover, our simulations demonstrate that the conjunction of a ZnPc skeleton with a cholesterol moiety may reduce the intrinsic molecular rotation of ZnPc in membranes, presumably leading to an increase of the generation efficiency of reactive oxygen species for PDT. The molecular insights obtained here are likely to help improve the rational design of novel photosensitizers with enhanced cellular uptake and photocytotoxic activity.
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Jeannotte, Marie-Eve, Maan Abul-Milh, J. Daniel Dubreuil, and Mario Jacques. "Binding of Actinobacillus pleuropneumoniae to Phosphatidylethanolamine." Infection and Immunity 71, no. 8 (August 2003): 4657–63. http://dx.doi.org/10.1128/iai.71.8.4657-4663.2003.
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ABSTRACT The gram-negative bacterium Actinobacillus pleuropneumoniae is the causative agent of porcine fibrinohemorrhagic necrotizing pleuropneumonia, a disease that causes important economic losses to the swine industry worldwide. In general, the initial step of bacterial colonization is attachment to host cells. The purpose of the present study was to evaluate the binding of A. pleuropneumoniae serotype 1 to phospholipids, which are the major constituents of biological membranes. Phospholipids serve as receptors for several bacteria, including respiratory pathogens. To study this effect, we used thin-layer chromatography overlay binding assays to test commercial phospholipids such as phosphatidic acid, phosphatidylcholine, phosphatidylserine, phosphatidylinositol, phosphatidylglycerol, and phosphatidylethanolamine (PE). Our results indicate that A. pleuropneumoniae serotype 1 binds to PE but not to the other phospholipids tested. Serotypes 5b and 7, which, along with serotype 1, are the most prevalent serotypes of A. pleuropneumoniae in North America, share the ability to bind PE. Inhibition of binding with a monoclonal antibody against A. pleuropneumoniae serotype 1 O antigen and the use of isogenic lipopolysaccharide (LPS) mutants of A. pleuropneumoniae serotype 1 showed that the O antigen seems to be implicated in the binding to PE, at least for A. pleuropneumoniae serotype 1. A. pleuropneumoniae was also shown to bind to a phospholipid extracted from swine lungs by using the method of Folch. Chemical staining with molybdenum blue and ninhydrin, migration with neutral, acidic, and basic solvent systems, and mass spectrometry analysis all indicated that this lipid is PE. This study is, to the best of our knowledge, the first description of A. pleuropneumoniae binding to phospholipids. Our data also suggest that LPS O antigens could be involved in binding to PE.
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Paparo, Domenico, Klaas-Jan Tielrooij, Huib Bakker, and Mischa Bonn. "TeraHertz Dielectric Relaxation of Biological Water Confined in Model Membranes made of Lyotropic Phospholipids." Molecular Crystals and Liquid Crystals 500, no. 1 (March 3, 2009): 108–17. http://dx.doi.org/10.1080/15421400802713769.
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Andryukov, B. G., I. N. Lyapun, and E. V. Matosova. "The role of membrane phospholipids in the implementation of protective strategies of bacteria." Journal of microbiology, epidemiology and immunobiology 97, no. 6 (January 20, 2021): 594–603. http://dx.doi.org/10.36233/0372-9311-2020-97-6-10.
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To maintain viability under stressful conditions of existence and the implementation of protective strategies, bacteria must receive signals and respond quickly to extreme changes in environmental parameters. The results of recent experimental studies complement the paradigm that has dominated since the 1970s on the predominant role of phospholipids (PL) as molecular building blocks in the formation of the cell wall of bacteria. Specific transformations of these lipid domains have shown to have a significant effect on the shape and function of cells, membrane remodeling, and the ability of bacteria to adapt to environmental stresses. The physiological role of bacterial PLs is pleiotropic and determines both cell integrity and cell function. In addition to the key structural role of membrane PL in the cell, their intermediate metabolites are able to act as secondary messengers and perform important signaling and regulatory functions. Modern studies of the mechanisms of detection and integration of signals from the environment that cause stationary-dynamic changes in phospholipid homeostasis and form pleiotropic resistant cellular bacterial phenotypes are of fundamental and practical interest. PL homeostasis was proved to be crucial for the pathogenesis of bacterial infections and is necessary not only to maintain the viability of bacteria, but also to ensure their growth during infection. The suppression of the biosynthesis of these macromolecules reduces the viability of bacteria. In recent decades, one of the main advances in the concept of "liquid mosaic" model of biological membranes has been the understanding of their domain structure. This discovery is of fundamental and practical interest, since phospholipid domains are a promising target for modern antimicrobial strategies. The aim of this review is to summarize modern ideas about the structural, metabolic and signaling role of membrane PL in the implementation of the protective mechanisms of bacteria and maintaining their viability in adverse environmental conditions.
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Andreev, Konstantin. "The Structural Role of Gangliosides: Insights from X-ray Scattering on Model Membranes." Current Medicinal Chemistry 27, no. 38 (November 12, 2020): 6548–70. http://dx.doi.org/10.2174/0929867327666200103093340.
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Background: Gangliosides are an essential component of eukaryotic plasma membranes implicated in multiple physiological processes. Little is known about molecular mechanisms underlying the distribution and functions of membrane gangliosides. The overwhelmingly complex organization of glycocalyx impedes the structural analysis on cell surface and the interplay between the lipid components. Advanced X-ray analytical tools applicable to studying biological interfaces call for the simplistic models that mimic ganglioside-enriched cellular membranes. Objective: To summarize the mechanistic evidences of ganglioside interactions with lipid environment and biologically active ligands using high-resolution synchrotron X-ray scattering. Methods: A comprehensive review of studies published over the last decade was done to discuss recent accomplishments and future trends. Results: Langmuir monolayers represent an adequate model system to assess the effect of gangliosides on membrane structure. Grazing incidence X-ray diffraction reveals a condensation effect by gangliosides on zwitterionic phospholipids with the cooperative packing of sialo- and phosphate groups. In turn, the arrangement of negatively charged lipids in ganglioside mixture remains unchanged due to the stretched conformation of carbohydrate moieties. Upon interaction with biological ligands, such as cholera toxin and galectins, the ganglioside redistribution within the ordered regions of monolayer follows distinct mechanistic patterns. The cholera toxin pentamer attached to the oligosaccharide core induces local transition from oblique to the hexagonal lattice resulting in phase coexistence. The incorporation of the A subunit responsible for endocytosis is further promoted by the acidic environment characteristic for endosomal space. X-ray reflectivity shows in-plane orientation of galectin dimers with the spatial mismatch between the lectin binding sites and ganglioside carbohydrates to perturb ceramide alkyl chains. Recent data also demonstrate sialic acid groups to be potential targets for novel peptide mimicking anticancer therapeutics. Conclusion: Coupled with surface X-ray scattering, the membrane mimetic approach allows for better understanding the biological role of gangliosides and their potential applications.
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Chin, Ramjeesingh, Hung, Ereño-Oreba, Cui, Laselva, Julien, and Bear. "Cholesterol Interaction Directly Enhances Intrinsic Activity of the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR)." Cells 8, no. 8 (July 31, 2019): 804. http://dx.doi.org/10.3390/cells8080804.
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The recent cryo-electron microscopy structures of zebrafish and the human cystic fibrosis transmembrane conductance regulator (CFTR) provided unprecedented insights into putative mechanisms underlying gating of its anion channel activity. Interestingly, despite predictions based on channel activity measurements in biological membranes, the structure of the detergent purified, phosphorylated, and ATP-bound human CFTR protein did not reveal a stably open conduction pathway. This study tested the hypothesis that the functional properties of the detergent solubilized CFTR protein used for structural determinations are different from those exhibited by CFTR purified under conditions that retain associated lipids native to the membrane. It was found that CFTR purified together with phospholipids and cholesterol using amphipol: A8-35, exhibited higher rates of catalytic activity, phosphorylation dependent channel activation and potentiation by the therapeutic compound, ivacaftor, than did CFTR purified in detergent. The catalytic activity of phosphorylated CFTR detergent micelles was rescued by the addition of phospholipids plus cholesterol, but not by phospholipids alone, arguing for a specific role for cholesterol in modulating this function. In summary, these studies highlight the importance of lipid interactions in the intrinsic activities and pharmacological potentiation of CFTR.
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Moss, Frank R., Steven R. Shuken, Jaron A. M. Mercer, Carolyn M. Cohen, Thomas M. Weiss, Steven G. Boxer, and Noah Z. Burns. "Ladderane phospholipids form a densely packed membrane with normal hydrazine and anomalously low proton/hydroxide permeability." Proceedings of the National Academy of Sciences 115, no. 37 (August 27, 2018): 9098–103. http://dx.doi.org/10.1073/pnas.1810706115.
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Ladderane lipids are unique to anaerobic ammonium-oxidizing (anammox) bacteria and are enriched in the membrane of the anammoxosome, an organelle thought to compartmentalize the anammox process, which involves the toxic intermediate hydrazine (N2H4). Due to the slow growth rate of anammox bacteria and difficulty of isolating pure ladderane lipids, experimental evidence of the biological function of ladderanes is lacking. We have synthesized two natural and one unnatural ladderane phosphatidylcholine lipids and compared their thermotropic properties in self-assembled bilayers to distinguish between [3]- and [5]-ladderane function. We developed a hydrazine transmembrane diffusion assay using a water-soluble derivative of a hydrazine sensor and determined that ladderane membranes are as permeable to hydrazine as straight-chain lipid bilayers. However, pH equilibration across ladderane membranes occurs 5–10 times more slowly than across straight-chain lipid membranes. Langmuir monolayer analysis and the rates of fluorescence recovery after photobleaching suggest that dense ladderane packing may preclude formation of proton/hydroxide-conducting water wires. These data support the hypothesis that ladderanes prevent the breakdown of the proton motive force rather than blocking hydrazine transmembrane diffusion in anammox bacteria.
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Tavasoli, Mahtab, Sarah Lahire, Taryn Reid, Maren Brodovsky, and Christopher R. McMaster. "Genetic diseases of the Kennedy pathways for membrane synthesis." Journal of Biological Chemistry 295, no. 51 (October 22, 2020): 17877–86. http://dx.doi.org/10.1074/jbc.rev120.013529.
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The two branches of the Kennedy pathways (CDP-choline and CDP-ethanolamine) are the predominant pathways responsible for the synthesis of the most abundant phospholipids, phosphatidylcholine and phosphatidylethanolamine, respectively, in mammalian membranes. Recently, hereditary diseases associated with single gene mutations in the Kennedy pathways have been identified. Interestingly, genetic diseases within the same pathway vary greatly, ranging from muscular dystrophy to spastic paraplegia to a childhood blinding disorder to bone deformations. Indeed, different point mutations in the same gene (PCYT1; CCTα) result in at least three distinct diseases. In this review, we will summarize and review the genetic diseases associated with mutations in genes of the Kennedy pathway for phospholipid synthesis. These single-gene disorders provide insight, indeed direct genotype-phenotype relationships, into the biological functions of specific enzymes of the Kennedy pathway. We discuss potential mechanisms of how mutations within the same pathway can cause disparate disease.
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Ahn, Taeho, Mihee Kim, Chul-Ho Yun, and Han-Jung Chae. "Functional Regulation of Hepatic Cytochrome P450 Enzymes by Physicochemical Properties of Phospholipids in Biological Membranes." Current Protein & Peptide Science 8, no. 5 (October 1, 2007): 496–505. http://dx.doi.org/10.2174/138920307782411392.
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Rajasekharan, Archita, and Sathyanarayana N. Gummadi. "Flip-Flop of Phospholipids in Proteoliposomes Reconstituted from Detergent Extract of Chloroplast Membranes: Kinetics and Phospholipid Specificity." PLoS ONE 6, no. 12 (December 12, 2011): e28401. http://dx.doi.org/10.1371/journal.pone.0028401.
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John, Karin, Susanne Schreiber, Janek Kubelt, Andreas Herrmann, and Peter Müller. "Transbilayer Movement of Phospholipids at the Main Phase Transition of Lipid Membranes: Implications for Rapid Flip-Flop in Biological Membranes." Biophysical Journal 83, no. 6 (December 2002): 3315–23. http://dx.doi.org/10.1016/s0006-3495(02)75332-0.
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Aamouche, Ahmed, and Erik Goormaghtigh. "FTIR-ATR biosensor based on self-assembled phospholipids surface: Haemophilia factor VIII diagnosis." Spectroscopy 22, no. 4 (2008): 223–34. http://dx.doi.org/10.1155/2008/690574.
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We report a new generic device suitable for the investigation of biological interactions by means of Fourier Transform Infrared (FTIR) spectroscopy. The research is focused on multi reflected evanescent optical radiation through a chemically modified surface of the attenuated total reflection (ATR) element (silicon or germanium). Using a wet chemistry approach, the original method is based on grafting of a bifunctional binding molecule (N-hydroxysuccinimidyl ester forms) at the surface of the Si or the Ge crystals. The functionalized surface permits then the foundation of different types of self-assembled phospholipid membranes. The obtained sensors allow the detection, in infrared spectral domain, of any perceptible molecular interaction or structural changes. The key experimental result concerns the coagulation factor VIII(FVIII). The principle of the diagnostic is related to the ability of FFVIIImolecules to bind specifically to phosphatidylserine (PS) membrane.
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Federovitch, Christine M., Ying Z. Jones, Amy H. Tong, Charles Boone, William A. Prinz, and Randolph Y. Hampton. "Genetic and Structural Analysis of Hmg2p-induced Endoplasmic Reticulum Remodeling in Saccharomyces cerevisiae." Molecular Biology of the Cell 19, no. 10 (October 2008): 4506–20. http://dx.doi.org/10.1091/mbc.e07-11-1188.
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The endoplasmic reticulum (ER) is highly plastic, and increased expression of distinct single ER-resident membrane proteins, such as HMG-CoA reductase (HMGR), can induce a dramatic restructuring of ER membranes into highly organized arrays. Studies on the ER-remodeling behavior of the two yeast HMGR isozymes, Hmg1p and Hmg2p, suggest that they could be mechanistically distinct. We examined the features of Hmg2p required to generate its characteristic structures, and we found that the molecular requirements are similar to those of Hmg1p. However, the structures generated by Hmg1p and Hmg2p have distinct cell biological features determined by the transmembrane regions of the proteins. In parallel, we conducted a genetic screen to identify HER genes (required for Hmg2p-induced ER Remodeling), further confirming that the mechanisms of membrane reorganization by these two proteins are distinct because most of the HER genes were required for Hmg2p but not Hmg1p-induced ER remodeling. One of the HER genes identified was PSD1, which encodes the phospholipid biosynthetic enzyme phosphatidylserine decarboxylase. This direct connection to phospholipid biosynthesis prompted a more detailed examination of the effects of Hmg2p on phospholipid mutants and composition. Our analysis revealed that overexpression of Hmg2p caused significant and specific growth defects in nulls of the methylation pathway for phosphatidylcholine biosynthesis that includes the Psd1p enzyme. Furthermore, increased expression of Hmg2p altered the composition of cellular phospholipids in a manner that implied a role for PSD1. These phospholipid effects, unlike Hmg2p-induced ER remodeling, required the enzymatic activity of Hmg2p. Together, our results indicate that, although related, Hmg2p- and Hmg1p-induced ER remodeling are mechanistically distinct.
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Tornesello, Anna Lucia, Antonella Borrelli, Luigi Buonaguro, Franco Maria Buonaguro, and Maria Lina Tornesello. "Antimicrobial Peptides as Anticancer Agents: Functional Properties and Biological Activities." Molecules 25, no. 12 (June 19, 2020): 2850. http://dx.doi.org/10.3390/molecules25122850.
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Antimicrobial peptides (AMPs), or host defense peptides, are small cationic or amphipathic molecules produced by prokaryotic and eukaryotic organisms that play a key role in the innate immune defense against viruses, bacteria and fungi. AMPs have either antimicrobial or anticancer activities. Indeed, cationic AMPs are able to disrupt microbial cell membranes by interacting with negatively charged phospholipids. Moreover, several peptides are capable to trigger cytotoxicity of human cancer cells by binding to negatively charged phosphatidylserine moieties which are selectively exposed on the outer surface of cancer cell plasma membranes. In addition, some AMPs, such as LTX-315, have shown to induce release of tumor antigens and potent damage associated molecular patterns by causing alterations in the intracellular organelles of cancer cells. Given the recognized medical need of novel anticancer drugs, AMPs could represent a potential source of effective therapeutic agents, either alone or in combination with other small molecules, in oncology. In this review we summarize and describe the properties and the mode of action of AMPs as well as the strategies to increase their selectivity toward specific cancer cells.