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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
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
Anqi Sheng, Jiangru Hong, Lulu Zhang, Yan Zhang, Guangqin Zhang
Voltage-gated K+ (KV ) currents play a crucial role in regulating pain by controlling neuronal excitability, and are divided into transient A-type currents (IA ) and delayed rectifier currents (IK ). The dorsal root ganglion (DRG) neurons are heterogeneous and the subtypes of KV currents display different levels in distinct cell sizes. To observe correlations of the subtypes of KV currents with DRG cell sizes, KV currents were recorded by whole-cell patch clamp in freshly isolated mouse DRG neurons. Results showed that IA occupied a high proportion in KV currents in medium- and large-diameter DRG neurons, whereas IK possessed a larger proportion of KV currents in small-diameter DRG neurons...
March 29, 2018: Journal of Membrane Biology
Tatsiana Ilyich, Oksana Charishnikova, Szymon Sekowski, Maria Zamaraeva, Vitali Cheshchevik, Iosif Dremza, Nina Cheshchevik, Lyudmila Kiryukhina, Elena Lapshina, Ilya Zavodnik
It is well known that the terpenoid ferutinin (4-oxy-6-(4-oxybenzoyloxy) dauc-8,9-en), isolated from the plant Ferula tenuisecta, considerably increases the permeability of artificial and cellular membranes to Ca2+ -ions and produces apoptotic cell death in different cell lines in a mitochondria-dependent manner. The present study was designed for further evaluation of the mechanism(s) of mitochondrial effects of ferutinin using isolated rat liver mitochondria. Our findings provide evidence for ferutinin at concentrations of 5-27 µM to decrease state 3 respiration and the acceptor control ratio in the case of glutamate/malate as substrates...
March 28, 2018: Journal of Membrane Biology
Michael C Owen, Waldemar Kulig, Tomasz Rog, Ilpo Vattulainen, Birgit Strodel
In an effort to delineate how cholesterol protects membrane structure under oxidative stress conditions, we monitored the changes to the structure of lipid bilayers comprising 30 mol% cholesterol and an increasing concentration of Class B oxidized 1-palmitoyl-2-oleoylphosphatidylcholine (POPC) glycerophospholipids, namely, 1-palmitoyl-2-(9'-oxo-nonanoyl)-sn-glycero-3-phosphocholine (PoxnoPC), and 1-palmitoyl-2-azelaoyl-sn-glycero-3-phosphocholine (PazePC), using atomistic molecular dynamics simulations. Increasing the content of oxidized phospholipids (oxPLs) from 0 to 60 mol% oxPL resulted in a characteristic reduction in bilayer thickness and increase in area per lipid, thereby increasing the exposure of the membrane hydrophobic region to water...
March 17, 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...
March 17, 2018: Journal of Membrane Biology
Svetlana S Efimova, Anastasiia A Zakharova, Roman Ya Medvedev, Olga S Ostroumova
The potential therapeutic applications of plant polyphenols in various neurological, cardiovascular, metabolic and malignant disorders determine the relevance of studying the molecular mechanisms of their action on the cell membranes. Here, the quantitative changes in the physical parameters of model bilayer lipid membranes upon the adsorption of plant polyphenols were evaluated. It was shown that butein and naringenin significantly decreased the intrinsic dipole potential of cholesterol-free and cholesterol-enriched membranes...
March 16, 2018: Journal of Membrane Biology
Konstantina Karathanou, Ana-Nicoleta Bondar
Lipid membrane interfaces are complex environments that host essential cellular processes such as binding of proteins or drug molecules. A key open question is how water molecules at the interface of membranes with anionic lipids participate in protein binding. To address this question, we studied the dynamics of water hydrogen bonding at the interface of membranes composed of phosphatidylcholine and phosphatidylglycerol, and implemented an algorithm to identify hydrogen-bonded networks at the interface of a lipid membrane, and to characterize their dynamics and linear connections...
March 9, 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...
March 8, 2018: Journal of Membrane Biology
Nadia Elghobashi-Meinhardt, Prasad Phatak, Ana-Nicoleta Bondar, Marcus Elstner, Jeremy C Smith
For the photocycle of the membrane protein bacteriorhodopsin to proceed efficiently, the thermal 13-cis to all-trans back-isomerization of the retinal chromophore must return the protein to its resting state on a time-scale of milliseconds. Here, we report on quantum mechanical/molecular mechanical energy calculations examining the structural and energetic determinants of the retinal cis-trans isomerization in the protein environment. The results suggest that a hydrogen-bonded network consisting of the retinal Schiff base, active site amino acid residues, and water molecules can stabilize the twisted retinal, thus reducing the intrinsic energy cost of the cis-trans thermal isomerization barrier...
March 8, 2018: Journal of Membrane Biology
Anne Grethen, David Glueck, Sandro Keller
Styrene/maleic acid (SMA) and related copolymers are attracting great interest because they solubilise membrane proteins and lipids to form polymer-encapsulated nanodiscs. These nanodiscs retain a lipid-bilayer core surrounded by a polymer rim and can harbour a membrane protein or a membrane-protein complex. SMA exists in different styrene/maleic acid molar ratios, which results in differences in hydrophobicity and solubilisation properties. We have recently demonstrated fast collisional lipid transfer among nanodiscs encapsulated by the relatively hydrophobic copolymer SMA(3:1)...
March 5, 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
Saša Rezelj, Mirijam Kozorog, Tomaž Švigelj, Nataša Poklar Ulrih, Nada Žnidaršič, Marjetka Podobnik, Gregor Anderluh
Archaeosomes are vesicles made of lipids from archaea. They possess many unique features in comparison to other lipid systems, with their high stability being the most prominent one, making them a promising system for biotechnological applications. Here, we report a preparation protocol of large unilamellar vesicles, giant unilamellar vesicles (GUVs), and nanodiscs from archaeal lipids with incorporated cholesterol. Incorporation of cholesterol led to additional increase in thermal stability of vesicles. Surface plasmon resonance, sedimentation assays, intrinsic tryptophan fluorescence measurements, calcein release experiments, and GUVs experiments showed that members of cholesterol-dependent cytolysins, listeriolysin O (LLO), and perfringolysin O (PFO), bind to cholesterol-rich archaeosomes and thereby retain their pore-forming activity...
February 23, 2018: Journal of Membrane Biology
Alma E V Andersson, Marina A Kasimova, Lucie Delemotte
Viral potassium channels (Kcv) are homologous to the pore module of complex [Formula: see text]-selective ion channels of cellular organisms. Due to their relative simplicity, they have attracted interest towards understanding the principles of [Formula: see text] conduction and channel gating. In this work, we construct a homology model of the [Formula: see text] open state, which we validate by studying the binding of known blockers and by monitoring ion conduction through the channel. Molecular dynamics simulations of this model reveal that the re-orientation of selectivity filter carbonyl groups coincides with the transport of potassium ions, suggesting a possible mechanism for fast gating...
February 23, 2018: Journal of Membrane Biology
Tahereh Ghane, Rene F Gorriz, Sandro Wrzalek, Senta Volkenandt, Ferand Dalatieh, Marco Reidelbach, Petra Imhof
Proton transfer in cytochrome c oxidase (CcO) from the cellular inside to the binuclear redox centre as well as proton pumping through the membrane takes place through proton entrance via two distinct pathways, the D- and K-channel. Both channels show a dependence of their hydration level on the protonation states of their key residues, K362 for the K-channel, and E286 or D132 for the D-channel. In the oxidative half of CcO's catalytic cycle the D-channel is the proton-conducting path. For this channel, an interplay of protonation state of the D-channel residues with the water and hydrogen-bond dynamics has been observed in molecular dynamics simulations of the CcO protein, embedded in a lipid bi-layer, modelled in different protonation states...
February 12, 2018: Journal of Membrane Biology
Kangmin Duan, Ayush Kumar
No abstract text is available yet for this article.
February 2018: Journal of Membrane Biology
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