We provide a kinetic characterization of (Na+, K+)-ATPase activity in a posterior gill microsomal fraction from the grapsid crab Goniopsis cruentata. (Na+, K+)-ATPase activity constitutes 95% of total ATPase activity, and sucrose density centrifugation reveals an ATPase activity peak between 25 and 35% sucrose, distributed into two, partially separated protein fractions. The (Na+, K+)-ATPase α-subunit

The maintenance of ionic homeostasis in the cytoplasm is an essential and crucial physiological process for all living beings. At cellular level, Na+ concentrations are maintained by specialized Na+ transporting molecular machines, which operate in the cell or plasma membrane. In eukaryotes Na+ transporting P-type ATPase play an important role in Na+ homeostasis that is known as Na+/K+-ATPase in animal

Cellular secreted proteins (secretome), together with cellular membrane proteins, collectively referred to as secretory and membrane proteins (SMPs) are a large potential source of biomarkers as they can be used to indicate cell types and conditions. SMPs have been shown to be ideal candidates for several clinically approved drug regimens including for cancer. This study aimed at performing a functional

Membrane proteins are the major component of plasma membranes, and they play crucial roles in all organisms. To understand the influence of the presence of KcsA channel on cell membrane electroporation induced by picosecond pulse trains (psPT), in this paper, the electroporation of KcsA membrane protein system and bare lipid bilayer system (POPC) with the applied psPT are simulated using molecular

The increasing resistance of many pathogens to most of the common antimicrobials requires the development of new substances with more effective antimicrobial properties. In the present work, we investigated the mechanism of the antimicrobial activity of novel water soluble ammonium quaternary benzanthrone (Compound B) on model membranes, composed of dipalmitoylphosphatidylcholine, 1-palmitoyl-2-ol

It was reported that nitric oxide (NO) donors increased the permeability of water-soluble compounds across intestinal membrane with neither loss of cell viability nor release of lactate dehydrogenase. Therefore, the detail mechanism of action of NO donors on the gastrointestinal membrane has yet to be clarified. We previously reported the possibility of the enhancing effect of the NO donor on the membrane

Abstract A planar lipid bilayer on a solid support serves as model system that explains fundamental aspects of membrane biology and enables us to characterize wide-range surface-sensitive techniques, including molecular engineering. The present study aims at understanding the process of single and multiple bilayer formation after the exposure of small unilamellar vesicles (SUVs) of dioleoyl phosphatidylcholine

The original version of the article is unfortunately missing the Acknowledgements section. Acknowledgments section is given below.

Human sodium-independent glucose cotransporter 1 (hGLUT1) has been studied for its tetramerization and multimerization at the cell surface. Homozygous or compound heterozygous mutations in hGLUT1 elicit GLUT1-deficiency syndrome (GLUT1-DS), a metabolic disorder, which results in impaired glucose transport into the brain. The reduced cell surface expression or loss of function have been shown for some

Introduction by Ana-Nicoleta Bondar, Biophysics Section Head Editor This issue of the Journal of Membrane Biology inaugurates Up-and-Coming Scientist, in which investigators at early career stages are invited to present recent research in the broad context of their discipline. We inaugurate Up-and-Coming Scientist with the essay by Dr. Elena Lesca of the ETH Zürich and the Paul Scherrer Institut, Switzerland

Abstract As a member of the kinesin-3 family, kinesin family member 16B (KIF16B) has a characteristic PhoX homology (PX) domain that binds to membranes containing phosphatidylinositol-3-phosphate (PI(3)P) and moves along microtubule filaments to the plus end via a process regulated by coiled coils in the stalk region in various cell types. The physiological function of KIF16B supports the transport

Bardoxolone methyl (CDDO-Me), a synthetic derivative of the naturally occurring triterpenoid oleanolic acid, displays strong antioxidant, anticancer and anti-inflammatory activities, according to different bibliographical sources. However, the understanding of its molecular mechanism is missing. Furthermore, CDDO-Me has displayed a significant cytotoxicity against various types of cancer cells. CDDO-Me

Abstract KCNQ2 channel is one of the important members of potassium voltage-gated channel. KCNQ2 is closely related to neuronal excitatory diseases including epilepsy and neuropathic pain, and also acts as a drug target of the anti-epileptic drug, retigabine (RTG). In the past few decades, RTG has shown strong efficacy in the treatment of refractory epilepsy but has been withdrawn from clinical use

Endosomal escape is a rate-limiting step in the cytosolic delivery of therapeutic drugs. Overcoming this barrier is crucial to achieve an effective biological based therapy. In this work, we evaluated the ability of a synthetic biomimetic peptide derived from the GALA to facilitate endosomal escape of protein drugs. Our results showed that the cytoplasmic distribution of GALA fusion proteins changed

Hyperpolarization-activated cation-nonselective (HCN) channels regulate electrical activity in the brain and heart in a cAMP-dependent manner. The voltage-gating of these channels is mediated by a transmembrane (TM) region but is additionally regulated by direct binding of cAMP to a cyclic nucleotide-binding (CNB) fold in the cytoplasmic C-terminal region. Cyclic AMP potentiation has been explained

Mitochondria are organelles with significant cellular functions, especially cellular bioenergetics and apoptosis. They are structural and functional elements of cell respiration with the electron transport system (ETS), whose role is to provide adenosine triphosphate (ATP), used as a source of chemical energy. The Krebs cycle and fatty acid oxidation take place within mitochondria. Other metabolic

Abstract The transport of water and several other small molecules across cell membranes is vital in many of the processes underlying reproduction. Fluid transport in cells and tissues inclusive of male reproductive organs are regulated by disparate isoforms of aquaporins (AQPs) in living organisms. Alteration in the expression, function and/or regulation of AQPs leads to some forms of male subfertility

Abstract Flavonols are the most widely distributed class of dietary flavonoids with a wide range of pharmacological properties due to their potent lipid peroxidation inhibition activity. The permeability and orientation of these compounds in lipid bilayers can provide an understanding of their antioxidant and lipid-peroxidation inhibition activity based on their structures at the molecular level. For

The behavior of the cinnamycin immobilized on the gold nanorod(AuNR) was investigated using surface plasmon resonance(SPR). For the comparison of the immobilized cinnamycin, the study for the free cinnamycin was also conducted. The bilayer was fabricated by tethering 1,2-dipalmitoyl-sn-glycero-3-phosphothioethanols on a gold surface to form a monolayer and then using liposomes to adsorb an outer layer

The characterization of the behavior of lipid-attached spin probes in a bilayer is of fundamental importance for correct interpretation of the results of both EPR and fluorescence studies of protein-membrane interactions. The knowledge of the immersion depth of TEMPO spin probe attached to lipid headgroup in TEMPO-PC is critical for the determination of the transverse location of fluorescence probes

The paper examines the effects of the antimicrobial agent triclosan on the functioning of the liver mitochondria of marsh frog (Pelophylax ridibundus (Pallas, 1771)). It was established that triclosan inhibits DNP-stimulated respiration of mitochondria and decreases respiratory control ratio. In addition, triclosan causes the collapse of the mitochondrial membrane potential on both types of substrates

Transmembrane electric potentials and membrane curvature have always provided pathways to mediate different cellular processes. We present results of molecular dynamics (MD) simulations of lipid monolayer composed of 1, 2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and cholesterol (CHOL) under a transverse electric field to monitor the effect of electric field on membrane containing ganglioside

Abstract Lysophosphatidylcholine (LPC) is a major atherogenic lipid that stimulates an increase in mitochondrial reactive oxygen species (mtROS) and the release of cytokines under inflammasome activation. However, the potential receptors of LPC in macrophages are poorly understood. Members of the transient receptor potential (TRP) channel superfamily, which is crucially involved in transducing environmental

Many natural products could induce apoptosis through mitochondrial pathways. However, direct interactions between natural products and mitochondria have rarely been reported. In this work, the effects and regulatory mechanisms of Jaceosidin on the isolated rat liver mitochondria have been studied. The results of the experiments which by introducing exogenous Ca2+ illustrated that Jaceosidin has the

The original version of the article unfortunately contained an error in the author group. Dr. Isabel Larré was not submitted and published in the original version.

Fengycins are compounds produced by bacteria of the Bacillus genus with strong antifungal activity. In this work, lipids extracted from fungal and oomycetal molds were used to assess the ability of fengycin to bind and insert into complex membrane models prepared as Langmuir lipid monolayers. In addition, fengycin-induced leakage in liposomes prepared from these complex lipid extracts was also evaluated

Effects of ibutilide, a class III antiarrhythmic drug, on delayed rectifier potassium currents (IK) in freshly isolated guinea pig ventricular myocytes were studied. Experiments were performed using the whole-cell configuration of patch-clamp technique under blockade of L-type calcium currents (Cav1). Ibutilide at concentrations ranging between 10 nM and 100 µM inhibited IKr in dose-dependent manner

Computational chemistry provides versatile methods for studying the properties and functioning of biological systems at different levels of precision and at different time scales. The aim of this article is to review the computational methodologies that are applicable to rhodopsins as archetypes for photoactive membrane proteins that are of great importance both in nature and in modern technologies

The high demand of the fetus for Docosahexaenoic acid, DHA, is satisfied by a concert of several mechanisms that take place in the placental terminal villi. Scarcity of laboratory data makes the detailed description of these mechanisms elusive. Here, the DHA transport across the placenta is modeled as a boundary value problem that accounts for diffusion, reactions with fatty acids binding proteins

The β2-adrenergic receptor (β2AR) is a membrane-bound G-protein-coupled receptor and an important drug target for asthma. Clinical studies report that the population variant Gln27Glu is associated with a differential response to common asthma drugs, such as albuterol, isoproterenol and terbutaline. Interestingly, the 27th amino acid is positioned on the N-terminal region that is the most flexible and

G protein-coupled receptors (GPCRs) play a pivotal role in the adaptive responses to cellular stresses such as hypoxia. In addition to influencing cellular gene expression profiles, hypoxic microenvironments can perturb membrane protein localization, altering GPCR effector scaffolding and altering downstream signaling. Studies using proteomics approaches have revealed significant regulation of GPCR

Mitochondria are dynamic organelles characterized by an ultrastructural organization which is essential in maintaining their quality control and ensuring functional efficiency. The complex mitochondrial network is the result of the two ongoing forces of fusion and fission of inner and outer membranes. Understanding the functional details of mitochondrial dynamics is physiologically relevant as perturbations

A subjective account is presented of challenges and excitement of being a postdoctoral trainee in the lab of James H. Prestegard at Yale University in New Haven, Connecticut from 1989 to 1991. This includes accounts of the early development of bicelles and of oriented sample NMR results that contributed to our modern understanding of the properties of the water-lipid interface of disordered phase biological

G protein-coupled receptors (GPCRs) are the largest class of membrane proteins involved in signal transduction and are characterized by seven transmembrane domain architecture interconnected by extra- and intracellular loops. These loops, along with the N- and C-terminal domains, constitute the extramembranous regions in GPCRs. These regions, accounting for ~ 40% or more amino acid residues across

Gap junctions provide a communication pathway between adjacent cells. They are formed by paired connexons that reside in the plasma membrane of their respective cell and their activity can be modulated by the bilayer composition. In this work, we study the dynamic behavior of a Cx26 connexon embedded in a POPC lipid bilayer, studying: the membrane protein interactions and the ion flux though the connexon

Biological membranes display a staggering complexity of lipids and proteins orchestrating cellular functions. Superior analytical tools coupled with numerous functional cellular screens have enabled us to query their role in cellular signalling, trafficking, guiding protein structure and function-all of which rely on the dynamic membrane lipid properties indispensable for proper cellular functions

The capability of the synchronization modulation (SM) technique in enhancing the function of Na/K pumps has been demonstrated in various cells and tissues, including cardiomyocytes, a monolayer of cultured MDCK kidney cells, peripheral blood vessels, and frog skeletal muscles. This study characterized the membrane potential hyperpolarization induced by SM in both physiological and high [K+]o conditions

Intracellular compartment drug delivery is a promising strategy for the treatment of diseases. By this way, medicines can delivered to particular intracellular compartments. This maximizes the therapeutic efficacy and safety of medicines, particularly of anticancer and antiviral drugs. Intracellular compartment drug delivery is either indirectly by targeting of cell nucleus as central compartment of

The large plasticity, dynamics and adaptability of biological membranes allow different modes of intrinsic and inducible permeability. These phenomena are of physiological importance for a number of natural functions related to cell death and can also be manipulated artificially for practical purposes like gene transfer, drug delivery, prevention of infections or anticancer therapy. For these advances

Receptors at the membrane of immune cells are the central players of innate and adaptative immunity, providing effective defence mechanisms against pathogens or cancer cells. Their function is intimately linked to their position at and within the membrane which provides accessibility, mobility as well as membrane proximal cytoskeleton anchoring, all of these elements playing important roles in the

Plasma membrane proteins perform a variety of important tasks in the cells. These tasks can be diverse as carrying nutrients across the plasma membrane, receiving chemical signals from outside the cell, translating them into intracellular action, and anchoring the cell in a particular location. When these crucial roles of plasma membrane proteins are considered, the need for their characterization

Fluorescent probes are widely employed to label lipids for the investigation of structural and dynamic properties of model and cell membranes through optical microscopy techniques. Although the effect of tagging a lipid with an organic dye is generally assumed to be negligible, optically modified lipids can nonetheless affect the local lipid structure and, in turn, the lipid lateral mobility. To better

At the neuromuscular junction (NMJ), the nicotinic acetylcholine receptor (nAChR) self-associates to give rise to rapid muscle movement. While lipid domains have maintained nAChR aggregates in vitro, their specific roles in nAChR clustering are currently unknown. In the present study, we carried out coarse-grained molecular dynamics simulations (CG-MD) of 1-4 nAChR molecules in two membrane environments:

Rhodopsin is the light receptor in photoreceptor cells of the retina and a prototypical G protein-coupled receptor. Two types of quaternary structures can be adopted by rhodopsin. If rhodopsin folds and attains a proper tertiary structure, it can then form oligomers and nanodomains within the photoreceptor cell membrane. In contrast, if rhodopsin misfolds, it cannot progress through the biosynthetic

The unique and ubiquitous bacterial lipoprotein biosynthesis pathway is an attractive new antibiotic target. Crystal structures of its three biosynthetic enzymes have been solved recently. The first enzyme, Phosphatidylglycerol:proLipoprotein diacylglyceryl Transferase (Lgt), which initiates the post-translational modification at the metabolic interface of protein biosynthesis, phospholipid biosynthesis

Bacterial pathogens are a major cause of foodborne diseases and food poisoning. To cope with the acid conditions encountered in different environments such as in fermented food or in the gastric compartment, neutralophilic bacteria have developed several adaptive mechanisms. One of those mechanisms, the amino acid dependent system, consumes intracellular protons in biochemical reactions. It involves

The activation mechanism of the ErbB family of receptors is of considerable medical interest as they are linked to a number of human cancers, including an aggressive form of breast cancer. In the rat analogue of the human ErbB2 receptor, referred to as Neu, a point mutation in the transmembrane domain (V664E) has been shown to trigger oncogenic transformation. While the structural impact of this mutation

Amyloid formation of the human islet amyloid polypeptide (hIAPP) correlates with a loss of insulin-producing beta cells in patients with type II diabetes mellitus. In this study, we investigated the binding of hIAPP to bilayers consisting of ganglioside lipids and dioleoylphosphatidylcholine (DOPC), which is a physiologically relevant lipid species for pancreatic beta cell-associated aggregation. The

The membrane-active protein Nogo-66 is found to induce interdigitation in dimyristoylphosphocholine membranes. Extensive molecular dynamics simulations have been employed to probe the interactions of Nogo-66 with these model membranes. This phase change happens when the temperature is close to the main transition temperature of the membrane (Tm) and only in the presence of the protein. No similar interdigitation

The major histocompatibility complex class II (MHC II) membrane proteins are key players in the adaptive immune response. An aberrant function of these molecules is associated with a large number of autoimmune diseases such as diabetes type I and chronic inflammatory diseases. The MHC class II is assembled from DQ alpha 1 and DQ beta 1 which come together as a heterodimer through GXXXG-mediated protein-protein

Phytochemicals are ubiquitous in naturally occurring dietary elements that exhibits diverse pharmacological properties over various pathological disorders, including cancer. Voltage gated K+ (KV) channel in the plasma membrane contributes to wide range of cellular processes including cancer progression. Therefore, modulation of KV channel is being considered as a novel potential target for cancer therapy

The intrinsically disordered proteins and protein regions (IDPs/IDPRs) do not have unique structures, but are known to be functionally important and their conformational flexibility and structural plasticity have engendered a paradigmatic shift in the classical sequence-structure-function maxim. Fundamental understanding in this field has significantly evolved since the discovery of this class of proteins

The resistance of pathogens to traditional antibiotics is currently a global issue of enormous concern. As the discovery and development of new antibiotics become increasingly challenging, synthetic antimicrobial lipopeptides (AMLPs) are now receiving renewed attention as a new class of antimicrobial agents. In contrast to traditional antibiotics, AMLPs act by physically disrupting the cell membrane

Several experimental and theoretical studies have extensively investigated the effects of a large diversity of antimicrobial peptides (AMPs) on model lipid bilayers and living cells. Many of these peptides disturb cells by forming pores in the plasma membrane that eventually lead to the cell death. The complexity of these peptide-lipid interactions is mainly related to electrostatic, hydrophobic and

Auxin regulates diverse processes involved in plant growth and development. AUX1 is the first identified and most widely investigated auxin importer, and plays an important role in root gravitropism and the development of lateral root and root hair. However, the regulation of auxin transport by AUX1 is still not well understood. In this study, we examined the effect of metal ions on AUX1 transport

Studies made in the Madin-Darby canine kidney (MDCK) epithelial cell line showed that ouabain regulates cell adhesion and cell-adhesion-related biological processes, such as migration. Here, we demonstrated that 10 nM ouabain accelerates collective cell migration and heals wounds in cultured MDCK cell monolayers. Ouabain-induced acceleration of cell migration depends on activation of the cSrc-ERK1/2

Muscle cells are routinely subjected to mechanical stretch but the impact of stretch on the organization of membrane domains is unknown. In this study, we characterize the effect of stretch on GPCR-Gαq protein signaling. Activation of this pathway leads to an increase in intracellular calcium. In muscle cells, GPCR-Gαq signals are enhanced when these proteins are localized in caveolae membrane domains

Membrane fusion, one of the most essential processes in the life of eukaryotes, occurs when two separate lipid bilayers merge into a continuous bilayer and internal contents of two separated membranes mingle. There is a certain class of proteins that assist the binding of the viral envelope to the target host cell and catalyzing fusion. All class I viral fusion proteins contain a highly conserved 20-25

Of all the macromolecular assemblies of life, the least understood is the biomembrane. This is especially true in regard to its atomic structure. Ideas on biomembranes, developed in the last 200 years, culminated in the fluid mosaic model of the membrane. In this essay, I provide a historical outline of how we arrived at our current understanding of biomembranes and the models we use to describe them