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Journal of Membrane Biology

Valentina G Tabbasum, Dermot M F Cooper
The fidelity of cAMP in controlling numerous cellular functions rests crucially on the precise organization of cAMP microdomains that are sustained by the scaffolding properties of adenylyl cyclase. Earlier studies suggested that AC8 enriches in lipid rafts where it interacts with cytoskeletal elements. However, these are not stable structures and little is known about the dynamics of AC8 secretion and its interactions. The present study addresses the role of the cytoskeleton in maintaining the AC8 microenvironment, particularly in the context of the trafficking route of AC8 and its interaction with caveolin1...
February 12, 2019: Journal of Membrane Biology
Masa Kanduser, Mojca Kokalj Imsirovic, Marko Usaj
Induced cell fusion is a powerful method for production of hybridoma in biotechnology and cell vaccines in medical applications. Among different alternatives, physical methods have an advantage, as they do not require any additives. Among them electrofusion, an electroporation-based cell fusion method holds a great promise. Electric pulses cause cell membrane permeabilization and due to pore formation bring cell membrane into the fusogenic state. At the same time, however, they compromise cell viability. We used a train of 8 × 100 µs electric pulses, delivered at 1 Hz with strengths ranging from 400 to 1600 V/cm...
January 22, 2019: Journal of Membrane Biology
Tesfaye Negash Asfaw, Vladimir E Bondarenko
Sodium ion channel is a membrane protein that plays an important role in excitable cells, as it is responsible for the initiation of action potentials. Understanding the electrical characteristics of sodium channels is essential in predicting their behavior under different physiological conditions. We investigated several Markov models for the human cardiac sodium channel NaV 1.5 to derive a minimal mathematical model that describes the reported experimental data obtained using major voltage clamp protocols...
January 14, 2019: Journal of Membrane Biology
Meishan Zhang, Shuang Yang, Minghui Shi, Shumiao Zhang, Tianxiang Zhang, Yimeng Li, Shanghua Xu, Muha Cha, Yuping Meng, Shaobi Lin, Juan Yu, Xuxin Li, Ali Mu, Defu Hu, Shuqiang Liu
In this study, we analyzed the main components of muskrat musk by gas chromatography-mass spectrometry, the results showed that muskrat musk contained fatty acids (29.32%), esters (31.89%), cholesterol (4.38%), cyclic ketones (16.31%), alcohols (6.42%) and other compounds, among which 9-octadecenoic acid accounted for 4.89%. We also analyzed the genes of the metabolic pathway in the scent gland at the transcriptomic level during musk-secreting and non-secreting seasons by RNA-seq (RNA sequencing). We detected 21 genes in the peroxisomal metabolic pathways, including PEX14(peroxin-14) and ACOX3(acyl-CoA oxidase), which exhibited significant differential expression between the musk-secreting season and the non-secreting season (p < 0...
January 2, 2019: Journal of Membrane Biology
Alexander D Dergunov, Eugeny V Savushkin, Liudmila V Dergunova, Dmitry Y Litvinov
ABCA1, ABCG1 transporters, and SR-B1 receptor are the major proteins involved in cholesterol efflux from cells. We superposed in silico the location of putative cholesterol (Chol)-binding motifs CRAC/CARC and CCM in human ABCA1, ABCG1, and SR-B1 with (1) transmembrane protein topology, (2) a profile of structural order of protein, and (3) with an influence of single amino acid substitutions on protein structure and function. ABCA1, ABCG1, and SR-B1 molecules contain 50, 19, and 13 Chol-binding motifs, respectively, that are localized either in membrane helices, or at membrane-water interface, or in water-exposed protein regions...
December 6, 2018: Journal of Membrane Biology
Justyna Mildner, Anita Wnętrzak, Patrycja Dynarowicz-Latka
Local anesthetics (LAs) are known to act on membrane level; however, the molecular mechanism of their activity is still not fully understood. One hypothesis holds that these drugs can incorporate into lipid membrane of nerve cells and in this way change conformation of channel proteins responsible for transport of sodium ions. However, the action of anesthetics is not limited to nerve cells. These drugs also affect other types of cells and organelles, causing severe side effects. In this paper, we applied Langmuir monolayers-as model of cellular membranes-and investigated interactions between selected amide-type local anesthetics (lidocaine prilocaine, mepivacaine and ropivacaine, in the form of hydrochlorides) and lipid components of natural membranes: cholesterol, POPC and cardiolipin (CL) and their mixtures (POPC/cholesterol and POPC/CL/cholesterol), which can serve as simplified models of nerve cell membranes, erythrocytes, and mitochondria...
November 30, 2018: Journal of Membrane Biology
Alok Jain, Ravi Kumar Verma, Ramasubbu Sankararamakrishnan
Major intrinsic protein (MIP) superfamily contains water-transporting AQP1 and glycerol-specific GlpF belonging to two major phylogenetic groups, namely aquaporins (AQPs) and aquaglyceroporins (AQGPs). MIP channels have six transmembrane helices (TM1 to TM6) and two half-helices (LB and LE). LE region contributes two residues to the aromatic/arginine (Ar/R) selectivity filter (SF) within the MIP channel. Bioinformatics analyses have shown that all AQGPs have an intra-helical salt-bridge (IHSB) in LE half-helix and all AQGPs and majority of AQPs have helix destabilizing Gly and/or Pro in the same region...
November 23, 2018: Journal of Membrane Biology
Yayue Huang, Shuai Guo, Shuxi Ren, Yafei Chen, Yong Zhan, Hailong An
Calcium-activated chloride channels (CaCCs) play important roles in a multitude of physiological processes, and in many cells types, TMEM16A was identified as the molecular basis of CaCC. Abnormal CaCC function has been implicated in variety of diseases, which reinforces the need for modulators of CaCCs/TMEM16A. However, there are few specific, clinical modulators of CaCCs. Here, we identified a potent novel activator of TMEM16A from a bank of traditional Chinese medicines (TCM) and explored its mechanism of activation by laser confocal scanning microscopy and patch clamping...
December 2018: Journal of Membrane Biology
Hanna Pruchnik, Aleksandra Włoch, Dorota Bonarska-Kujawa, Halina Kleszczyńska
Interactions of tributyltin (TBTA) and triphenyltin (TPhTA) 2-[4 (dimethylamino)phenylazo]benzoates, showing promising cytostatic activity against tumor cells, with erythrocytes and with erythrocyte membranes and model lipid membranes have been investigated. The effect of TBTA and TPhTA on the erythrocyte and its model membrane was investigated by the microscopic and spectroscopic methods. Interaction of tin complexes with the membrane was determined on the basis of hemolytic activity, changes induced in the shape of erythrocytes, as well as physicochemical parameters of the membrane, such as fluidity...
December 2018: Journal of Membrane Biology
Ran Friedman, Syma Khalid, Camilo Aponte-Santamaría, Elena Arutyunova, Marlon Becker, Kevin J Boyd, Mikkel Christensen, João T S Coimbra, Simona Concilio, Csaba Daday, Floris J van Eerden, Pedro A Fernandes, Frauke Gräter, Davit Hakobyan, Andreas Heuer, Konstantina Karathanou, Fabian Keller, M Joanne Lemieux, Siewert J Marrink, Eric R May, Antara Mazumdar, Richard Naftalin, Mónica Pickholz, Stefano Piotto, Peter Pohl, Peter Quinn, Maria J Ramos, Birgit Schiøtt, Durba Sengupta, Lucia Sessa, Stefano Vanni, Talia Zeppelin, Valeria Zoni, Ana-Nicoleta Bondar, Carmen Domene
This is a perspective article entitled "Frontiers in computational biophysics: understanding conformational dynamics of complex lipid mixtures relevant to biology" which is following a CECAM meeting with the same name.
December 2018: Journal of Membrane Biology
Felipe de Sá Rocha, Rafael Ramos da Silva, Gustavo Henrique Ribeiro Codeceira, Maria do Carmo Alves de Lima, Ivan da Rocha Pitta, Maria Danielly Lima de Oliveira, César Augusto Souza de Andrade
Oxazolidine derivatives (OxD) are five ring-membered compounds that contain at least one oxygen and nitrogen in their molecular structure. OxD are known due to several therapeutic activities such as anticancer and antibiotic properties. In this paper, we performed a thermodynamic analysis of the mixed films composed by dipalmitoylphosphatidylglycerol (DPPG), dipalmitoylphosphoethanolamine (DPPE), dipalmitoyl phosphatidylcholine (DPPC) or L-α phosphatidylcholine (PC) with a novel oxazolidine derivate (OxD)...
December 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...
December 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...
December 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...
December 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...
December 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...
December 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...
December 2018: Journal of Membrane Biology
Kenneth M Sterling, William R Harvey
The present research report describes Na+ /H+ antiport by brush border membrane vesicles isolated from whole larvae of Aedes aegypti (AeBBMVw). Our hypothesis is that acid quenching of acridine orange by AeBBMVw is predominantly mediated by Na+ /H+ antiport via the NHA1 component of the AeBBMVw in the absence of amino acids and ATP. AeNHA1 is a Na+ /H+ antiporter that has been postulated to exchange Na+ and H+ across the apical plasma membrane in posterior midgut of A. aegypti larvae. Its principal function is to recycle the H+ and Na+ that are transported during amino acid uptake, e...
November 3, 2018: 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
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
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