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Journal of Membrane Biology

Katarzyna Makyła-Juzak, Anna Chachaj-Brekiesz, Patrycja Dynarowicz-Latka, Paweł Dąbczyński, Joanna Zemla
Glycosaminoglycans (GAGs) are essential components of the extracellular matrices (ECMs) located on the outer surface of cellular membranes. They belong to the group of polysaccharides involved in diverse biological processes acting on the surface and across natural lipid membranes. Recently, particular attention has been focused on possible role of GAGs in the amyloid deposits. The amyloid formation is related to a disorder in protein folding, causing that soluble-in normal conditions-peptides become deposited extracellularly as insoluble fibrils, impairing tissue structure and its function...
July 20, 2018: Journal of Membrane Biology
Alexander M Firsov, Irina D Pogozheva, Sergey I Kovalchuk, Elena A Kotova, Yuri N Antonenko
In contrast to the parent pentadecapeptide gramicidin A (gA), some of its cationic analogs have been shown previously to form large-diameter pores in lipid membranes. These pores are permeable to fluorescent dyes, which allows one to monitor pore formation by using the fluorescence de-quenching assay. According to the previously proposed model, the gA analog with lysine substituted for alanine at position 3, [Lys3]gA, forms pores by a homopentameric assembly of gramicidin double-stranded β-helical dimers. Here, we studied the newly synthesized analogs of [Lys3]gA with single, double and triple substitutions of isoleucines for tryptophans at positions 9, 11, 13, and 15...
July 11, 2018: Journal of Membrane Biology
Ana-Nicoleta Bondar, Sandro Keller
No abstract text is available yet for this article.
June 29, 2018: Journal of Membrane Biology
James C Gumbart, Martin B Ulmschneider, Anthony Hazel, Stephen H White, Jakob P Ulmschneider
The original version of the article unfortunately contained an error in NIH support grant number RO1-GM74639 in the Acknowledgements section. The correct grant number is RO1-GM74637. This has been corrected with this erratum.
June 25, 2018: Journal of Membrane Biology
Joanna Doskocz, Dominik Drabik, Grzegorz Chodaczek, Magdalena Przybyło, Marek Langner
Bending rigidity coefficient describes propensity of a lipid bilayer to deform. In order to measure the parameter experimentally using flickering noise spectroscopy, the microscopic imaging is required, which necessitates the application of giant unilamellar vesicles (GUV) lipid bilayer model. The major difficulty associated with the application of the model is the statistical character of GUV population with respect to their size and the homogeneity of lipid bilayer composition, if a mixture of lipids is used...
June 1, 2018: Journal of Membrane Biology
Margarita Leyva-Leyva, Alejandro Sandoval, Ricardo Felix, Ricardo González-Ramírez
Dystrophin is a cytoskeleton-linked membrane protein that binds to a larger multiprotein assembly called the dystrophin-associated glycoprotein complex (DGC). The deficiency of dystrophin or the components of the DGC results in the loss of connection between the cytoskeleton and the extracellular matrix with significant pathophysiological implications in skeletal and cardiac muscle as well as in the nervous system. Although the DGC plays an important role in maintaining membrane stability, it can also be considered as a versatile and flexible molecular complex that contribute to the cellular organization and dynamics of a variety of proteins at specific locations in the plasma membrane...
May 19, 2018: Journal of Membrane Biology
Alejandro de Athayde Moncorvo Collado, Paula B Salazar, Carlos Minahk
The interaction of enterodiol and the well-described polyphenol epigallocatechin gallate (EGCG) with hepatic membranes has been matter of interest in the last few years. On one hand, EGCG is only able to bind to the phospholipid polar head groups, as it has been already described in synthetic lipid bilayers and erythrocyte membranes but cannot get inserted into the hydrophobic core or be transported into the lumen of membrane vesicles. On the other, enterodiol has no interaction with non-energized membranes either, but it is able to interact and even be transported upon addition of ATP...
May 4, 2018: Journal of Membrane Biology
Alexander Kyrychenko, Nathan M Lim, Victor Vasquez-Montes, Mykola V Rodnin, J Alfredo Freites, Linh P Nguyen, Douglas J Tobias, David L Mobley, Alexey S Ladokhin
Dynamic disorder of the lipid bilayer presents a challenge for establishing structure-function relationships in membranous systems. The resulting structural heterogeneity is especially evident for peripheral and spontaneously inserting membrane proteins, which are not constrained by the well-defined transmembrane topology and exert their action in the context of intimate interaction with lipids. Here, we propose a concerted approach combining depth-dependent fluorescence quenching with Molecular Dynamics simulation to decipher dynamic interactions of membrane proteins with the lipid bilayers...
June 2018: Journal of Membrane Biology
James C Gumbart, Martin B Ulmschneider, Anthony Hazel, Stephen H White, Jakob P Ulmschneider
We show that the free energy of inserting hydrophobic peptides into lipid bilayer membranes from surface-aligned to transmembrane inserted states can be reliably calculated using atomistic models. We use two entirely different computational methods: high temperature spontaneous peptide insertion calculations as well as umbrella sampling potential-of-mean-force (PMF) calculations, both yielding the same energetic profiles. The insertion free energies were calculated using two different protein and lipid force fields (OPLS protein/united-atom lipids and CHARMM36 protein/all-atom lipids) and found to be independent of the simulation parameters...
June 2018: Journal of Membrane Biology
Henriette S Frislev, Janni Nielsen, Jesper Nylandsted, Daniel Otzen
Cholesterol (chol) is important in all mammalian cells as a modulator of membrane fluidity. However, its low solubility is a challenge for controlled delivery to membranes. Here we introduce a new tool to deliver chol to membranes, namely, liprotides, i.e., protein-lipid complexes composed of a fatty acid core decorated with partially denatured protein. We focus on liprotides prepared by incubating Ca2+ -depleted α-lactalbumin with oleic acid (OA) for 1 h at 20 °C (lip20) or 80 °C (lip80). The binding and membrane delivery properties of liprotides is compared to the widely chol transporter methyl-β-cyclodextrin (mBCD)...
April 17, 2018: Journal of Membrane Biology
Ioanna Tremi, Dimitrios Anagnostopoulos, Ellas Spyratou, Paraskevi Gkeka, Alexandros G Georgakilas, Chryssostomos Chatgilialoglu, Zoe Cournia
Unsaturated fatty acids are found in humans predominantly in the cis configuration. Fatty acids in the trans configuration are primarily the result of human processing (trans fats), but can also be formed endogenously by radical stress. The cis-trans isomerization of fatty acids by free radicals could be connected to several pathologies. Trans fats have been linked to an increased risk of coronary artery disease; however, the reasons for the resulting pathogenesis remain unclear. Here, we investigate the effect of a mono-trans isomer of arachidonic acid (C20:4-5trans, 8cis, 11cis, 14cis) produced by free radicals in physiological concentration on a model erythrocyte membrane using a combined experimental and theoretical approach...
April 2, 2018: Journal of Membrane Biology
Małgorzata Jurak, Robert Mroczka, Rafał Łopucki
Lauryl gallate (LG) is an antioxidant agent. However, it exhibits poor solubility in water. Its interactions with the membrane result in structure evolution thus affecting the membrane functionality. In this paper the Brewster angle microscope coupled with the Langmuir trough was applied to determine the morphology, phase behaviour, thickness and miscibility of ternary Langmuir monolayers with equal mole fractions of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC); 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and an increasing mole fraction of LG...
April 2018: Journal of Membrane Biology
Yu-Di Hsu, Yu-Fen Huang, Yih-Jiuan Pan, Li-Kun Huang, Ya-Yun Liao, Wei-Hua Lin, Tzu-Yin Liu, Ching-Hung Lee, Rong-Long Pan
Plant vacuolar H+ -transporting inorganic pyrophosphatase (V-PPase; EC is a crucial enzyme that exists on the tonoplast to maintain pH homeostasis across the vacuolar membrane. This enzyme generates proton gradient between cytosol and vacuolar lumen by hydrolysis of a metabolic byproduct, pyrophosphate (PP i ). The regulation of V-PPase at protein level has drawn attentions of many workers for decades, but its mechanism is still unclear. In this work, we show that AVP1, the V-PPase from Arabidopsis thaliana, is a target protein for regulatory 14-3-3 proteins at the vacuolar membrane, and all twelve 14-3-3 isoforms were analyzed for their association with AVP1...
April 2018: Journal of Membrane Biology
Desirée Magalhães Dos Santos, Camila Valesca Jardim Rocha, Elita Ferreira da Silveira, Marcelo Augusto Germani Marinho, Marisa Raquel Rodrigues, Nichole Osti Silva, Ailton da Silva Ferreira, Neusa Fernandes de Moura, Gabriel Jorge Sagrera Darelli, Elizandra Braganhol, Ana Paula Horn, Vânia Rodrigues de Lima
Rapanea ferruginea antioxidant and antitumoral properties were not explored before in literature. This study aimed to investigate these biological activities for the R. ferruginea leaf extract and correlate them with its phenolic content and influence in biological membrane dynamics. Thus, in this study, anti/pro-oxidative properties of R. ferruginea leaf extract by in vitro DPPH and TBARS assays, with respect to the free radical reducing potential and to its activity regarding membrane free radical-induced peroxidation, respectively...
April 2018: Journal of Membrane Biology
M Laura Fernández, Marcelo Raúl Risk, P Thomas Vernier
Molecular dynamics simulations of lipid bilayers in aqueous systems reveal how an applied electric field stabilizes the reorganization of the water-membrane interface into water-filled, membrane-spanning, conductive pores with a symmetric, toroidal geometry. The pore formation process and the resulting symmetric structures are consistent with other mathematical approaches such as continuum models formulated to describe the electroporation process. Some experimental data suggest, however, that the shape of lipid electropores in living cell membranes may be asymmetric...
April 2018: Journal of Membrane Biology
F Castellani, J Teissié, P T Vernier
Since 2003, molecular dynamics simulations of lipid bilayers have provided valuable insights into the mechanisms underlying electropermeabilization (electroporation)-an electric field-induced increase in the permeability of biological membranes. The convention in these studies has been to apply the electric field normal to the plane of the membrane. In a typical electroporation application, however, where the electric field is reasonably uniform and unidirectional, the field is perpendicular to the membrane only at a few locations-for spherical cells only at the poles of the cells along the axis defined by the direction of the electric field...
April 2018: Journal of Membrane Biology
Florin Ciobanu, Muriel Golzio, Eugenia Kovacs, Justin Teissié
Electric pulses, when applied to a cell suspension, induce a reversible permeabilization of the plasma membrane. This permeabilized state is a long-lived process (minutes). The biophysical molecular mechanisms supporting the membrane reorganization associated to its permeabilization remain poorly understood. Modeling the transmembrane structures as toroidal lipidic pores cannot explain why they are long-lived and why their resealing is under the control of the ATP level. Our results describe the effect of the level of free Calcium ions...
April 2018: Journal of Membrane Biology
S Morteza Seyed Jafari, Maziar Shafighi, Helmut Beltraminelli, Benedikt Weber, Ralph A Schmid, Thomas Geiser, Amiq Gazdhar, Robert E Hunger
Despite advances in understanding the underlying mechanisms of flap necrosis and improvement in surgical techniques, skin flap necrosis after reconstructive surgery remains a crucial issue. We investigated the efficacy of electroporation-mediated IL-10 gene transfer to random skin flap with an aim to accelerate wound healing and improve skin flap survival. Nine male Wistar rats (300-330 g) were divided in two groups (a) control group (n = 5), only surgery no gene transfer, and (b) experimental group, received electroporation-mediated IL-10 gene transfer 24 h before the surgery as prophylaxis (n = 4)...
April 2018: Journal of Membrane Biology
Esin B Sözer, C Florencia Pocetti, P Thomas Vernier
Imaging of fluorescent small molecule transport into electropermeabilized cells reveals polarized patterns of entry, which must reflect in some way the mechanisms of the migration of these molecules across the compromised membrane barrier. In some reports, transport occurs primarily across the areas of the membrane nearest the positive electrode (anode), but in others cathode-facing entry dominates. Here we compare YO-PRO-1, propidium, and calcein uptake into U-937 cells after nanosecond (6 ns) and microsecond (220 µs) electric pulse exposures...
April 2018: Journal of Membrane Biology
Masa Bosnjak, Urska Kamensek, Gregor Sersa, Danijela Stolfa, Jaka Lavrencak, Maja Cemazar
No abstract text is available yet for this article.
April 2018: Journal of Membrane Biology
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