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Journal of Membrane Biology

Caner Yildirim, Ramazan Bal
ERG (ether-a-go-go-related gene) channels are the members of the voltage-dependent potassium channel family, which have three subtypes, as ERG1 (Kv 11.1), ERG2 (Kv 11.2), and ERG3 (Kv11.3). There is no information on ERG channels in the cochlear nucleus (CN) neurons, which is the first relay station of the auditory pathway. As occur in some of congenital long QT Syndromes (LQTS), mutation of the KCNQ11 genes for ERG channel has been reported to be accompanied by hearing loss. For that reason, we aimed to study biophysical properties and physiological importance, and contribution of ERG K+ currents to the formation of action potentials in the stellate and bushy neurons of the ventral cochlear nucleus (VCN)...
September 11, 2018: Journal of Membrane Biology
Sang-Ryong Lee, Jin-Won Park
The effect of the trehalose on the physical properties of the fluidic lipid bilayer was studied using surface plasmon resonance (SPR) and cyclic voltammetry (CV). The bilayer was fabricated by tethering 1,2-dipalmitoyl-sn-glycero-3-phosphothioethanol on a gold surface to form a monolayer and then using liposomes to adsorb an upper layer on the tethered monolayer. The liposomes were prepared with a desired ratio (mol/mol) of trehalose to lipid, before the adsorption was performed. The formation of the adsorbed layer was monitored with SPR, and the SPR responses were converted to the surface density of the layer...
September 8, 2018: Journal of Membrane Biology
Andrzej Teisseyre, Anna Palko-Labuz, Anna Uryga, Krystyna Michalak
The influence of a prenylated flavonoid-6-prenylnaringenin (6-PR) and selected non-prenylated flavonoids: acacetin, chrysin, baicalein, wogonin, and luteolin on the activity of voltage-gated potassium channels Kv1.3 was investigated in human leukemic Jurkat T cells. Electrophysiological measurements were accompanied by studies on the cytotoxic effect of the examined compounds on Jurkat T cells. Electrophysiological studies were performed using the whole-cell patch-clamp technique. Cell viability was determined using the MTT assay...
September 5, 2018: Journal of Membrane Biology
Agata Wawrzkiewicz-Jałowiecka, Paulina Trybek, Łukasz Machura, Beata Dworakowska, Zbigniew J Grzywna
BK channels are potassium selective and exhibit large single-channel conductance. They play an important physiological role in glioma cells: they are involved in cell growth and extensive migrating behavior. Due to the fact that these processes are accompanied by changes in membrane stress, here, we examine mechanosensitive properties of BK channels from human glioblastoma cells (gBK channels). Experiments were performed by the use of patch-clamp method on excised patches under membrane suction (0-40 mmHg) at membrane hyper- and depolarization...
August 9, 2018: Journal of Membrane Biology
Jingchao Tang, Hairong Yin, Jialu Ma, Wenfei Bo, Yang Yang, Jin Xu, Yiyao Liu, Yubin Gong
In this paper, the membrane electroporation induced by the terahertz electric field is simulated by means of the molecular dynamics method. The influences of the waveform and frequency of the applied terahertz electric field on the electroporation and the unique features of the process of the electroporation with the applied terahertz electric field are given. It shows that whether the electroporation can happen depends on the waveform of the applied terahertz electric field when the magnitude is not large enough...
August 9, 2018: Journal of Membrane Biology
Dil Diaz, Ronald J Clarke
The catalytic α-subunits of both the Na+ ,K+ -ATPase and the gastric H+ ,K+ -ATPase possess lysine-rich N-termini which project into the cytoplasm. Due to conflicting experimental results, it is currently unclear whether the N-termini play a role in ion pump function or regulation, and, if they do, by what mechanism. Comparison of the lysine frequencies of the N-termini of both proteins with those of all of their extramembrane domains showed that the N-terminal lysine frequencies are far higher than one would expect simply from exposure to the aqueous solvent...
July 28, 2018: Journal of Membrane Biology
Anthony R Braun, Michael M Lacy, Vanessa C Ducas, Zhiming Chen, Tobias Baumgart, Elizabeth Rhoades, Jonathan N Sachs
The original version of the article unfortunately contained error in author group; two authors were not submitted and published in the original version. Also the funding information is erroneously omitted.
July 27, 2018: 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
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...
August 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...
August 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...
August 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)...
August 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...
August 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...
August 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...
August 2018: Journal of Membrane Biology
Ana-Nicoleta Bondar, Sandro Keller
No abstract text is available yet for this article.
June 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 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...
June 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...
June 2018: Journal of Membrane Biology
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