Membranes: Thin layers of tissue which cover parts of the body, separate adjacent cavities, or connect adjacent structures.Membrane Lipids: Lipids, predominantly phospholipids, cholesterol and small amounts of glycolipids found in membranes including cellular and intracellular membranes. These lipids may be arranged in bilayers in the membranes with integral proteins between the layers and peripheral proteins attached to the outside. Membrane lipids are required for active transport, several enzymatic activities and membrane formation.Cell Membrane: The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.Intracellular Membranes: Thin structures that encapsulate subcellular structures or ORGANELLES in EUKARYOTIC CELLS. They include a variety of membranes associated with the CELL NUCLEUS; the MITOCHONDRIA; the GOLGI APPARATUS; the ENDOPLASMIC RETICULUM; LYSOSOMES; PLASTIDS; and VACUOLES.Membranes, Artificial: Artificially produced membranes, such as semipermeable membranes used in artificial kidney dialysis (RENAL DIALYSIS), monomolecular and bimolecular membranes used as models to simulate biological CELL MEMBRANES. These membranes are also used in the process of GUIDED TISSUE REGENERATION.Membrane Potentials: The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).Membrane Fluidity: The motion of phospholipid molecules within the lipid bilayer, dependent on the classes of phospholipids present, their fatty acid composition and degree of unsaturation of the acyl chains, the cholesterol concentration, and temperature.Erythrocyte Membrane: The semi-permeable outer structure of a red blood cell. It is known as a red cell 'ghost' after HEMOLYSIS.Spinal Curvatures: Deformities of the SPINE characterized by abnormal bending or flexure in the vertebral column. They may be bending forward (KYPHOSIS), backward (LORDOSIS), or sideway (SCOLIOSIS).Lipid Bilayers: Layers of lipid molecules which are two molecules thick. Bilayer systems are frequently studied as models of biological membranes.Cell Membrane Permeability: A quality of cell membranes which permits the passage of solvents and solutes into and out of cells.Basement Membrane: A darkly stained mat-like EXTRACELLULAR MATRIX (ECM) that separates cell layers, such as EPITHELIUM from ENDOTHELIUM or a layer of CONNECTIVE TISSUE. The ECM layer that supports an overlying EPITHELIUM or ENDOTHELIUM is called basal lamina. Basement membrane (BM) can be formed by the fusion of either two adjacent basal laminae or a basal lamina with an adjacent reticular lamina of connective tissue. BM, composed mainly of TYPE IV COLLAGEN; glycoprotein LAMININ; and PROTEOGLYCAN, provides barriers as well as channels between interacting cell layers.Liposomes: Artificial, single or multilaminar vesicles (made from lecithins or other lipids) that are used for the delivery of a variety of biological molecules or molecular complexes to cells, for example, drug delivery and gene transfer. They are also used to study membranes and membrane proteins.Membrane Transport Proteins: Membrane proteins whose primary function is to facilitate the transport of molecules across a biological membrane. Included in this broad category are proteins involved in active transport (BIOLOGICAL TRANSPORT, ACTIVE), facilitated transport and ION CHANNELS.Unilamellar Liposomes: Single membrane vesicles, generally made of PHOSPHOLIPIDS.Gravitropism: The directional growth of organisms in response to gravity. In plants, the main root is positively gravitropic (growing downwards) and a main stem is negatively gravitropic (growing upwards), irrespective of the positions in which they are placed. Plant gravitropism is thought to be controlled by auxin (AUXINS), a plant growth substance. (From Concise Dictionary of Biology, 1990)Models, Biological: Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.Microscopy, Electron: Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.Membrane Glycoproteins: Glycoproteins found on the membrane or surface of cells.Protein Transport: The process of moving proteins from one cellular compartment (including extracellular) to another by various sorting and transport mechanisms such as gated transport, protein translocation, and vesicular transport.Mitochondrial Membranes: The two lipoprotein layers in the MITOCHONDRION. The outer membrane encloses the entire mitochondrion and contains channels with TRANSPORT PROTEINS to move molecules and ions in and out of the organelle. The inner membrane folds into cristae and contains many ENZYMES important to cell METABOLISM and energy production (MITOCHONDRIAL ATP SYNTHASE).Protein Binding: The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.Phosphatidylcholines: Derivatives of phosphatidic acids in which the phosphoric acid is bound in ester linkage to a choline moiety. Complete hydrolysis yields 1 mole of glycerol, phosphoric acid and choline and 2 moles of fatty acids.Protein Structure, Tertiary: The level of protein structure in which combinations of secondary protein structures (alpha helices, beta sheets, loop regions, and motifs) pack together to form folded shapes called domains. Disulfide bridges between cysteines in two different parts of the polypeptide chain along with other interactions between the chains play a role in the formation and stabilization of tertiary structure. Small proteins usually consist of only one domain but larger proteins may contain a number of domains connected by segments of polypeptide chain which lack regular secondary structure.Synaptic Membranes: Cell membranes associated with synapses. Both presynaptic and postsynaptic membranes are included along with their integral or tightly associated specializations for the release or reception of transmitters.Cell Line: Established cell cultures that have the potential to propagate indefinitely.Models, Molecular: Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.Calcium: A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.Phosphatidylethanolamines: Derivatives of phosphatidic acids in which the phosphoric acid is bound in ester linkage to an ethanolamine moiety. Complete hydrolysis yields 1 mole of glycerol, phosphoric acid and ethanolamine and 2 moles of fatty acids.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Carrier Proteins: Transport proteins that carry specific substances in the blood or across cell membranes.Escherichia coli: A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.Electrophoresis, Polyacrylamide Gel: Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.Cell Fractionation: Techniques to partition various components of the cell into SUBCELLULAR FRACTIONS.Mutation: Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.Temperature: The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.Hydrogen-Ion Concentration: The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Detergents: Purifying or cleansing agents, usually salts of long-chain aliphatic bases or acids, that exert cleansing (oil-dissolving) and antimicrobial effects through a surface action that depends on possessing both hydrophilic and hydrophobic properties.Bacterial Proteins: Proteins found in any species of bacterium.Microscopy, Fluorescence: Microscopy of specimens stained with fluorescent dye (usually fluorescein isothiocyanate) or of naturally fluorescent materials, which emit light when exposed to ultraviolet or blue light. Immunofluorescence microscopy utilizes antibodies that are labeled with fluorescent dye.Golgi Apparatus: A stack of flattened vesicles that functions in posttranslational processing and sorting of proteins, receiving them from the rough ENDOPLASMIC RETICULUM and directing them to secretory vesicles, LYSOSOMES, or the CELL MEMBRANE. The movement of proteins takes place by transfer vesicles that bud off from the rough endoplasmic reticulum or Golgi apparatus and fuse with the Golgi, lysosomes or cell membrane. (From Glick, Glossary of Biochemistry and Molecular Biology, 1990)Time Factors: Elements of limited time intervals, contributing to particular results or situations.Endoplasmic Reticulum: A system of cisternae in the CYTOPLASM of many cells. In places the endoplasmic reticulum is continuous with the plasma membrane (CELL MEMBRANE) or outer membrane of the nuclear envelope. If the outer surfaces of the endoplasmic reticulum membranes are coated with ribosomes, the endoplasmic reticulum is said to be rough-surfaced (ENDOPLASMIC RETICULUM, ROUGH); otherwise it is said to be smooth-surfaced (ENDOPLASMIC RETICULUM, SMOOTH). (King & Stansfield, A Dictionary of Genetics, 4th ed)Extraembryonic Membranes: The thin layers of tissue that surround the developing embryo. There are four extra-embryonic membranes commonly found in VERTEBRATES, such as REPTILES; BIRDS; and MAMMALS. They are the YOLK SAC, the ALLANTOIS, the AMNION, and the CHORION. These membranes provide protection and means to transport nutrients and wastes.Cells, Cultured: Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.Phototropism: The directional growth of organisms in response to light. In plants, aerial shoots usually grow towards light. The phototropic response is thought to be controlled by auxin (= AUXINS), a plant growth substance. (From Concise Dictionary of Biology, 1990)Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.Endocytosis: Cellular uptake of extracellular materials within membrane-limited vacuoles or microvesicles. ENDOSOMES play a central role in endocytosis.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Protein Structure, Secondary: The level of protein structure in which regular hydrogen-bond interactions within contiguous stretches of polypeptide chain give rise to alpha helices, beta strands (which align to form beta sheets) or other types of coils. This is the first folding level of protein conformation.Molecular Conformation: The characteristic three-dimensional shape of a molecule.Gravity Sensing: Process whereby a cell, bodily structure, or organism (animal or plant) receives or detects a gravity stimulus. Gravity sensing plays an important role in the directional growth and development of an organism (GRAVITROPISM).Recombinant Fusion Proteins: Recombinant proteins produced by the GENETIC TRANSLATION of fused genes formed by the combination of NUCLEIC ACID REGULATORY SEQUENCES of one or more genes with the protein coding sequences of one or more genes.Binding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.Stereognosis: Perception of shape and form of objects by TOUCH, via tactile stimuli.Protein Conformation: The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).Hydrophobic and Hydrophilic Interactions: The thermodynamic interaction between a substance and WATER.Microscopy, Confocal: A light microscopic technique in which only a small spot is illuminated and observed at a time. An image is constructed through point-by-point scanning of the field in this manner. Light sources may be conventional or laser, and fluorescence or transmitted observations are possible.Plant Root Cap: A cone-shaped structure in plants made up of a mass of meristematic cells that covers and protects the tip of a growing root. It is the putative site of gravity sensing in plant roots.Freeze Fracturing: Preparation for electron microscopy of minute replicas of exposed surfaces of the cell which have been ruptured in the frozen state. The specimen is frozen, then cleaved under high vacuum at the same temperature. The exposed surface is shadowed with carbon and platinum and coated with carbon to obtain a carbon replica.Fluorescent Dyes: Agents that emit light after excitation by light. The wave length of the emitted light is usually longer than that of the incident light. Fluorochromes are substances that cause fluorescence in other substances, i.e., dyes used to mark or label other compounds with fluorescent tags.Computer Simulation: Computer-based representation of physical systems and phenomena such as chemical processes.Cornea: The transparent anterior portion of the fibrous coat of the eye consisting of five layers: stratified squamous CORNEAL EPITHELIUM; BOWMAN MEMBRANE; CORNEAL STROMA; DESCEMET MEMBRANE; and mesenchymal CORNEAL ENDOTHELIUM. It serves as the first refracting medium of the eye. It is structurally continuous with the SCLERA, avascular, receiving its nourishment by permeation through spaces between the lamellae, and is innervated by the ophthalmic division of the TRIGEMINAL NERVE via the ciliary nerves and those of the surrounding conjunctiva which together form plexuses. (Cline et al., Dictionary of Visual Science, 4th ed)Molecular Weight: The sum of the weight of all the atoms in a molecule.Cattle: Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.Cell Membrane Structures: Structures which are part of the CELL MEMBRANE or have cell membrane as a major part of their structure.Potassium: An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.Microvilli: Minute projections of cell membranes which greatly increase the surface area of the cell.Penile Induration: A condition characterized by hardening of the PENIS due to the formation of fibrous plaques on the dorsolateral aspect of the PENIS, usually involving the membrane (tunica albuginea) surrounding the erectile tissue (corpus cavernosum penis). This may eventually cause a painful deformity of the shaft or constriction of the urethra, or both.Erythrocytes: Red blood cells. Mature erythrocytes are non-nucleated, biconcave disks containing HEMOGLOBIN whose function is to transport OXYGEN.Cytoplasm: The part of a cell that contains the CYTOSOL and small structures excluding the CELL NUCLEUS; MITOCHONDRIA; and large VACUOLES. (Glick, Glossary of Biochemistry and Molecular Biology, 1990)Rabbits: The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.Subcellular Fractions: Components of a cell produced by various separation techniques which, though they disrupt the delicate anatomy of a cell, preserve the structure and physiology of its functioning constituents for biochemical and ultrastructural analysis. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p163)Thermodynamics: A rigorously mathematical analysis of energy relationships (heat, work, temperature, and equilibrium). It describes systems whose states are determined by thermal parameters, such as temperature, in addition to mechanical and electromagnetic parameters. (From Hawley's Condensed Chemical Dictionary, 12th ed)Ion Channels: Gated, ion-selective glycoproteins that traverse membranes. The stimulus for ION CHANNEL GATING can be due to a variety of stimuli such as LIGANDS, a TRANSMEMBRANE POTENTIAL DIFFERENCE, mechanical deformation or through INTRACELLULAR SIGNALING PEPTIDES AND PROTEINS.Cholesterol: The principal sterol of all higher animals, distributed in body tissues, especially the brain and spinal cord, and in animal fats and oils.Kinetics: The rate dynamics in chemical or physical systems.Mitochondria: Semiautonomous, self-reproducing organelles that occur in the cytoplasm of all cells of most, but not all, eukaryotes. Each mitochondrion is surrounded by a double limiting membrane. The inner membrane is highly invaginated, and its projections are called cristae. Mitochondria are the sites of the reactions of oxidative phosphorylation, which result in the formation of ATP. They contain distinctive RIBOSOMES, transfer RNAs (RNA, TRANSFER); AMINO ACYL T RNA SYNTHETASES; and elongation and termination factors. Mitochondria depend upon genes within the nucleus of the cells in which they reside for many essential messenger RNAs (RNA, MESSENGER). Mitochondria are believed to have arisen from aerobic bacteria that established a symbiotic relationship with primitive protoeukaryotes. (King & Stansfield, A Dictionary of Genetics, 4th ed)Biological Transport, Active: The movement of materials across cell membranes and epithelial layers against an electrochemical gradient, requiring the expenditure of metabolic energy.Elasticity: Resistance and recovery from distortion of shape.Permeability: Property of membranes and other structures to permit passage of light, heat, gases, liquids, metabolites, and mineral ions.Biomechanical Phenomena: The properties, processes, and behavior of biological systems under the action of mechanical forces.Phosphatidylserines: Derivatives of phosphatidic acids in which the phosphoric acid is bound in ester linkage to a serine moiety. Complete hydrolysis yields 1 mole of glycerol, phosphoric acid and serine and 2 moles of fatty acids.Electric Conductivity: The ability of a substrate to allow the passage of ELECTRONS.Diffusion: The tendency of a gas or solute to pass from a point of higher pressure or concentration to a point of lower pressure or concentration and to distribute itself throughout the available space. Diffusion, especially FACILITATED DIFFUSION, is a major mechanism of BIOLOGICAL TRANSPORT.Mathematics: The deductive study of shape, quantity, and dependence. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Models, Chemical: Theoretical representations that simulate the behavior or activity of chemical processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.Solubility: The ability of a substance to be dissolved, i.e. to form a solution with another substance. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Surface Properties: Characteristics or attributes of the outer boundaries of objects, including molecules.Peptides: Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are linear polypeptides that are normally synthesized on RIBOSOMES.Refraction, Ocular: Refraction of LIGHT effected by the media of the EYE.Gravitation: Acceleration produced by the mutual attraction of two masses, and of magnitude inversely proportional to the square of the distance between the two centers of mass. It is also the force imparted by the earth, moon, or a planet to an object near its surface. (From NASA Thesaurus, 1988)Membrane Potential, Mitochondrial: The voltage difference, normally maintained at approximately -180mV, across the INNER MITOCHONDRIAL MEMBRANE, by a net movement of positive charge across the membrane. It is a major component of the PROTON MOTIVE FORCE in MITOCHONDRIA used to drive the synthesis of ATP.Purple Membrane: Functionally and structurally differentiated, purple-pigmented regions of the cytoplasmic membrane of some strains of Halobacterium halobium. The membrane develops under anaerobic conditions and is made almost entirely of the purple pigment BACTERIORHODOPSINS. (From Singleton & Sainsbury Dictionary of Microbiology and Molecular Biology, 2d ed)Sodium: A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23.Lipids: A generic term for fats and lipoids, the alcohol-ether-soluble constituents of protoplasm, which are insoluble in water. They comprise the fats, fatty oils, essential oils, waxes, phospholipids, glycolipids, sulfolipids, aminolipids, chromolipids (lipochromes), and fatty acids. (Grant & Hackh's Chemical Dictionary, 5th ed)Corneal Topography: The measurement of curvature and shape of the anterior surface of the cornea using techniques such as keratometry, keratoscopy, photokeratoscopy, profile photography, computer-assisted image processing and videokeratography. This measurement is often applied in the fitting of contact lenses and in diagnosing corneal diseases or corneal changes including keratoconus, which occur after keratotomy and keratoplasty.Signal Transduction: The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.Sequence Homology, Amino Acid: The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.Water: A clear, odorless, tasteless liquid that is essential for most animal and plant life and is an excellent solvent for many substances. The chemical formula is hydrogen oxide (H2O). (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Static Electricity: The accumulation of an electric charge on a objectExocytosis: Cellular release of material within membrane-limited vesicles by fusion of the vesicles with the CELL MEMBRANE.Endosomes: Cytoplasmic vesicles formed when COATED VESICLES shed their CLATHRIN coat. Endosomes internalize macromolecules bound by receptors on the cell surface.Fluorescent Antibody Technique: Test for tissue antigen using either a direct method, by conjugation of antibody with fluorescent dye (FLUORESCENT ANTIBODY TECHNIQUE, DIRECT) or an indirect method, by formation of antigen-antibody complex which is then labeled with fluorescein-conjugated anti-immunoglobulin antibody (FLUORESCENT ANTIBODY TECHNIQUE, INDIRECT). The tissue is then examined by fluorescence microscopy.Scoliosis: An appreciable lateral deviation in the normally straight vertical line of the spine. (Dorland, 27th ed)Form Perception: The sensory discrimination of a pattern shape or outline.Adenosine Triphosphate: An adenine nucleotide containing three phosphate groups esterified to the sugar moiety. In addition to its crucial roles in metabolism adenosine triphosphate is a neurotransmitter.Cricetinae: A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.Recombinant Proteins: Proteins prepared by recombinant DNA technology.Micelles: Particles consisting of aggregates of molecules held loosely together by secondary bonds. The surface of micelles are usually comprised of amphiphatic compounds that are oriented in a way that minimizes the energy of interaction between the micelle and its environment. Liquids that contain large numbers of suspended micelles are referred to as EMULSIONS.Nictitating Membrane: A fold of the mucous membrane of the CONJUNCTIVA in many animals. At rest, it is hidden in the medial canthus. It can extend to cover part or all of the cornea to help clean the CORNEA.Bruch Membrane: The inner layer of CHOROID, also called the lamina basalis choroideae, located adjacent to the RETINAL PIGMENT EPITHELIUM; (RPE) of the EYE. It is a membrane composed of the basement membranes of the choriocapillaris ENDOTHELIUM and that of the RPE. The membrane stops at the OPTIC NERVE, as does the RPE.Transport Vesicles: Vesicles that are involved in shuttling cargo from the interior of the cell to the cell surface, from the cell surface to the interior, across the cell or around the cell to various locations.Spectrometry, Fluorescence: Measurement of the intensity and quality of fluorescence.Escherichia coli Proteins: Proteins obtained from ESCHERICHIA COLI.Octoxynol: Nonionic surfactant mixtures varying in the number of repeating ethoxy (oxy-1,2-ethanediyl) groups. They are used as detergents, emulsifiers, wetting agents, defoaming agents, etc. Octoxynol-9, the compound with 9 repeating ethoxy groups, is a spermatocide.Microscopy, Immunoelectron: Microscopy in which the samples are first stained immunocytochemically and then examined using an electron microscope. Immunoelectron microscopy is used extensively in diagnostic virology as part of very sensitive immunoassays.Cytosol: Intracellular fluid from the cytoplasm after removal of ORGANELLES and other insoluble cytoplasmic components.Cloning, Molecular: The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.Phase Transition: A change of a substance from one form or state to another.Models, Anatomic: Three-dimensional representation to show anatomic structures. Models may be used in place of intact animals or organisms for teaching, practice, and study.Nucleic Acid Conformation: The spatial arrangement of the atoms of a nucleic acid or polynucleotide that results in its characteristic 3-dimensional shape.Dogs: The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)Green Fluorescent Proteins: Protein analogs and derivatives of the Aequorea victoria green fluorescent protein that emit light (FLUORESCENCE) when excited with ULTRAVIOLET RAYS. They are used in REPORTER GENES in doing GENETIC TECHNIQUES. Numerous mutants have been made to emit other colors or be sensitive to pH.Porins: Porins are protein molecules that were originally found in the outer membrane of GRAM-NEGATIVE BACTERIA and that form multi-meric channels for the passive DIFFUSION of WATER; IONS; or other small molecules. Porins are present in bacterial CELL WALLS, as well as in plant, fungal, mammalian and other vertebrate CELL MEMBRANES and MITOCHONDRIAL MEMBRANES.Microscopy, Electron, Scanning: Microscopy in which the object is examined directly by an electron beam scanning the specimen point-by-point. The image is constructed by detecting the products of specimen interactions that are projected above the plane of the sample, such as backscattered electrons. Although SCANNING TRANSMISSION ELECTRON MICROSCOPY also scans the specimen point by point with the electron beam, the image is constructed by detecting the electrons, or their interaction products that are transmitted through the sample plane, so that is a form of TRANSMISSION ELECTRON MICROSCOPY.Stress, Mechanical: A purely physical condition which exists within any material because of strain or deformation by external forces or by non-uniform thermal expansion; expressed quantitatively in units of force per unit area.Actins: Filamentous proteins that are the main constituent of the thin filaments of muscle fibers. The filaments (known also as filamentous or F-actin) can be dissociated into their globular subunits; each subunit is composed of a single polypeptide 375 amino acids long. This is known as globular or G-actin. In conjunction with MYOSINS, actin is responsible for the contraction and relaxation of muscle.Cytoskeleton: The network of filaments, tubules, and interconnecting filamentous bridges which give shape, structure, and organization to the cytoplasm.Blotting, Western: Identification of proteins or peptides that have been electrophoretically separated by blot transferring from the electrophoresis gel to strips of nitrocellulose paper, followed by labeling with antibody probes.Vacuoles: Any spaces or cavities within a cell. They may function in digestion, storage, secretion, or excretion.Structure-Activity Relationship: The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.Microscopy, Electron, Transmission: Electron microscopy in which the ELECTRONS or their reaction products that pass down through the specimen are imaged below the plane of the specimen.Biometry: The use of statistical and mathematical methods to analyze biological observations and phenomena.Light: That portion of the electromagnetic spectrum in the visible, ultraviolet, and infrared range.Electrophysiology: The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.HeLa Cells: The first continuously cultured human malignant CELL LINE, derived from the cervical carcinoma of Henrietta Lacks. These cells are used for VIRUS CULTIVATION and antitumor drug screening assays.Lordosis: The anterior concavity in the curvature of the lumbar and cervical spine as viewed from the side. The term usually refers to abnormally increased curvature (hollow back, saddle back, swayback). It does not include lordosis as normal mating posture in certain animals ( = POSTURE + SEX BEHAVIOR, ANIMAL).Transfection: The uptake of naked or purified DNA by CELLS, usually meaning the process as it occurs in eukaryotic cells. It is analogous to bacterial transformation (TRANSFORMATION, BACTERIAL) and both are routinely employed in GENE TRANSFER TECHNIQUES.COS Cells: CELL LINES derived from the CV-1 cell line by transformation with a replication origin defective mutant of SV40 VIRUS, which codes for wild type large T antigen (ANTIGENS, POLYOMAVIRUS TRANSFORMING). They are used for transfection and cloning. (The CV-1 cell line was derived from the kidney of an adult male African green monkey (CERCOPITHECUS AETHIOPS).)Rotation: Motion of an object in which either one or more points on a line are fixed. It is also the motion of a particle about a fixed point. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Cell Polarity: Orientation of intracellular structures especially with respect to the apical and basolateral domains of the plasma membrane. Polarized cells must direct proteins from the Golgi apparatus to the appropriate domain since tight junctions prevent proteins from diffusing between the two domains.Phosphatidylglycerols: A nitrogen-free class of lipids present in animal and particularly plant tissues and composed of one mole of glycerol and 1 or 2 moles of phosphatidic acid. Members of this group differ from one another in the nature of the fatty acids released on hydrolysis.Microsomes: Artifactual vesicles formed from the endoplasmic reticulum when cells are disrupted. They are isolated by differential centrifugation and are composed of three structural features: rough vesicles, smooth vesicles, and ribosomes. Numerous enzyme activities are associated with the microsomal fraction. (Glick, Glossary of Biochemistry and Molecular Biology, 1990; from Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)Cryoelectron Microscopy: Electron microscopy involving rapid freezing of the samples. The imaging of frozen-hydrated molecules and organelles permits the best possible resolution closest to the living state, free of chemical fixatives or stains.Models, Theoretical: Theoretical representations that simulate the behavior or activity of systems, processes, or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.Immunoblotting: Immunologic method used for detecting or quantifying immunoreactive substances. The substance is identified by first immobilizing it by blotting onto a membrane and then tagging it with labeled antibodies.Fetal Membranes, Premature Rupture: Spontaneous tearing of the membranes surrounding the FETUS any time before the onset of OBSTETRIC LABOR. Preterm PROM is membrane rupture before 37 weeks of GESTATION.Receptors, Cell Surface: Cell surface proteins that bind signalling molecules external to the cell with high affinity and convert this extracellular event into one or more intracellular signals that alter the behavior of the target cell (From Alberts, Molecular Biology of the Cell, 2nd ed, pp693-5). Cell surface receptors, unlike enzymes, do not chemically alter their ligands.Tympanic Membrane: An oval semitransparent membrane separating the external EAR CANAL from the tympanic cavity (EAR, MIDDLE). It contains three layers: the skin of the external ear canal; the core of radially and circularly arranged collagen fibers; and the MUCOSA of the middle ear.Descemet Membrane: A layer of the cornea. It is the basal lamina of the CORNEAL ENDOTHELIUM (from which it is secreted) separating it from the CORNEAL STROMA. It is a homogeneous structure composed of fine collagenous filaments, and slowly increases in thickness with age.Chlorides: Inorganic compounds derived from hydrochloric acid that contain the Cl- ion.X-Ray Diffraction: The scattering of x-rays by matter, especially crystals, with accompanying variation in intensity due to interference effects. Analysis of the crystal structure of materials is performed by passing x-rays through them and registering the diffraction image of the rays (CRYSTALLOGRAPHY, X-RAY). (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Magnetic Resonance Spectroscopy: Spectroscopic method of measuring the magnetic moment of elementary particles such as atomic nuclei, protons or electrons. It is employed in clinical applications such as NMR Tomography (MAGNETIC RESONANCE IMAGING).Neurons: The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.Cytoplasmic Vesicles: Membrane-limited structures derived from the plasma membrane or various intracellular membranes which function in storage, transport or metabolism.Calorimetry, Differential Scanning: Differential thermal analysis in which the sample compartment of the apparatus is a differential calorimeter, allowing an exact measure of the heat of transition independent of the specific heat, thermal conductivity, and other variables of the sample.Microscopy, Atomic Force: A type of scanning probe microscopy in which a probe systematically rides across the surface of a sample being scanned in a raster pattern. The vertical position is recorded as a spring attached to the probe rises and falls in response to peaks and valleys on the surface. These deflections produce a topographic map of the sample.Protein Multimerization: The assembly of the QUATERNARY PROTEIN STRUCTURE of multimeric proteins (MULTIPROTEIN COMPLEXES) from their composite PROTEIN SUBUNITS.Perceptual Closure: The tendency to perceive an incomplete pattern or object as complete or whole. This includes the Gestalt Law of Closure.Extracorporeal Membrane Oxygenation: Application of a life support system that circulates the blood through an oxygenating system, which may consist of a pump, a membrane oxygenator, and a heat exchanger. Examples of its use are to assist victims of smoke inhalation injury, respiratory failure, and cardiac failure.Sphingomyelins: A class of sphingolipids found largely in the brain and other nervous tissue. They contain phosphocholine or phosphoethanolamine as their polar head group so therefore are the only sphingolipids classified as PHOSPHOLIPIDS.Lens, Crystalline: A transparent, biconvex structure of the EYE, enclosed in a capsule and situated behind the IRIS and in front of the vitreous humor (VITREOUS BODY). It is slightly overlapped at its margin by the ciliary processes. Adaptation by the CILIARY BODY is crucial for OCULAR ACCOMMODATION.Saccharomyces cerevisiae Proteins: Proteins obtained from the species SACCHAROMYCES CEREVISIAE. The function of specific proteins from this organism are the subject of intense scientific interest and have been used to derive basic understanding of the functioning similar proteins in higher eukaryotes.Cercopithecus aethiops: A species of CERCOPITHECUS containing three subspecies: C. tantalus, C. pygerythrus, and C. sabeus. They are found in the forests and savannah of Africa. The African green monkey (C. pygerythrus) is the natural host of SIMIAN IMMUNODEFICIENCY VIRUS and is used in AIDS research.Lysosomes: A class of morphologically heterogeneous cytoplasmic particles in animal and plant tissues characterized by their content of hydrolytic enzymes and the structure-linked latency of these enzymes. The intracellular functions of lysosomes depend on their lytic potential. The single unit membrane of the lysosome acts as a barrier between the enzymes enclosed in the lysosome and the external substrate. The activity of the enzymes contained in lysosomes is limited or nil unless the vesicle in which they are enclosed is ruptured. Such rupture is supposed to be under metabolic (hormonal) control. (From Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)Osmosis: Tendency of fluids (e.g., water) to move from the less concentrated to the more concentrated side of a semipermeable membrane.Immunohistochemistry: Histochemical localization of immunoreactive substances using labeled antibodies as reagents.Urologic Surgical Procedures, Male: Surgery performed on the male genitalia.Protein Sorting Signals: Amino acid sequences found in transported proteins that selectively guide the distribution of the proteins to specific cellular compartments.Peptide Fragments: Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.DNA: A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).Nerve Tissue ProteinsProteins: Linear POLYPEPTIDES that are synthesized on RIBOSOMES and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of AMINO ACIDS determines the shape the polypeptide will take, during PROTEIN FOLDING, and the function of the protein.Rats, Sprague-Dawley: A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Anions: Negatively charged atoms, radicals or groups of atoms which travel to the anode or positive pole during electrolysis.Phosphatidylinositol 4,5-Diphosphate: A phosphoinositide present in all eukaryotic cells, particularly in the plasma membrane. It is the major substrate for receptor-stimulated phosphoinositidase C, with the consequent formation of inositol 1,4,5-triphosphate and diacylglycerol, and probably also for receptor-stimulated inositol phospholipid 3-kinase. (Kendrew, The Encyclopedia of Molecular Biology, 1994)Protein Processing, Post-Translational: Any of various enzymatically catalyzed post-translational modifications of PEPTIDES or PROTEINS in the cell of origin. These modifications include carboxylation; HYDROXYLATION; ACETYLATION; PHOSPHORYLATION; METHYLATION; GLYCOSYLATION; ubiquitination; oxidation; proteolysis; and crosslinking and result in changes in molecular weight and electrophoretic motility.Phosphatidylinositols: Derivatives of phosphatidic acids in which the phosphoric acid is bound in ester linkage to the hexahydroxy alcohol, myo-inositol. Complete hydrolysis yields 1 mole of glycerol, phosphoric acid, myo-inositol, and 2 moles of fatty acids.Polyethylene Glycols: Polymers of ETHYLENE OXIDE and water, and their ethers. They vary in consistency from liquid to solid depending on the molecular weight indicated by a number following the name. They are used as SURFACTANTS, dispersing agents, solvents, ointment and suppository bases, vehicles, and tablet excipients. Some specific groups are NONOXYNOLS, OCTOXYNOLS, and POLOXAMERS.Complement Membrane Attack Complex: A product of COMPLEMENT ACTIVATION cascade, regardless of the pathways, that forms transmembrane channels causing disruption of the target CELL MEMBRANE and cell lysis. It is formed by the sequential assembly of terminal complement components (COMPLEMENT C5B; COMPLEMENT C6; COMPLEMENT C7; COMPLEMENT C8; and COMPLEMENT C9) into the target membrane. The resultant C5b-8-poly-C9 is the "membrane attack complex" or MAC.Glycoproteins: Conjugated protein-carbohydrate compounds including mucins, mucoid, and amyloid glycoproteins.Freeze Etching: A replica technique in which cells are frozen to a very low temperature and cracked with a knife blade to expose the interior surfaces of the cells or cell membranes. The cracked cell surfaces are then freeze-dried to expose their constituents. The surfaces are now ready for shadowing to be viewed using an electron microscope. This method differs from freeze-fracturing in that no cryoprotectant is used and, thus, allows for the sublimation of water during the freeze-drying process to etch the surfaces.CHO Cells: CELL LINE derived from the ovary of the Chinese hamster, Cricetulus griseus (CRICETULUS). The species is a favorite for cytogenetic studies because of its small chromosome number. The cell line has provided model systems for the study of genetic alterations in cultured mammalian cells.Molecular Structure: The location of the atoms, groups or ions relative to one another in a molecule, as well as the number, type and location of covalent bonds.Plasmids: Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.Guanosine Triphosphate: Guanosine 5'-(tetrahydrogen triphosphate). A guanine nucleotide containing three phosphate groups esterified to the sugar moiety.Macromolecular Substances: Compounds and molecular complexes that consist of very large numbers of atoms and are generally over 500 kDa in size. In biological systems macromolecular substances usually can be visualized using ELECTRON MICROSCOPY and are distinguished from ORGANELLES by the lack of a membrane structure.Lysosome-Associated Membrane Glycoproteins: Ubiquitously expressed integral membrane glycoproteins found in the LYSOSOME.Cardiolipins: Acidic phospholipids composed of two molecules of phosphatidic acid covalently linked to a molecule of glycerol. They occur primarily in mitochondrial inner membranes and in bacterial plasma membranes. They are the main antigenic components of the Wassermann-type antigen that is used in nontreponemal SYPHILIS SERODIAGNOSIS.Guinea Pigs: A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research.Cations: Positively charged atoms, radicals or groups of atoms which travel to the cathode or negative pole during electrolysis.Proton-Translocating ATPases: Multisubunit enzymes that reversibly synthesize ADENOSINE TRIPHOSPHATE. They are coupled to the transport of protons across a membrane.Patch-Clamp Techniques: An electrophysiologic technique for studying cells, cell membranes, and occasionally isolated organelles. All patch-clamp methods rely on a very high-resistance seal between a micropipette and a membrane; the seal is usually attained by gentle suction. The four most common variants include on-cell patch, inside-out patch, outside-out patch, and whole-cell clamp. Patch-clamp methods are commonly used to voltage clamp, that is control the voltage across the membrane and measure current flow, but current-clamp methods, in which the current is controlled and the voltage is measured, are also used.Enzyme Activation: Conversion of an inactive form of an enzyme to one possessing metabolic activity. It includes 1, activation by ions (activators); 2, activation by cofactors (coenzymes); and 3, conversion of an enzyme precursor (proenzyme or zymogen) to an active enzyme.Vitelline Membrane: The plasma membrane of the egg.Osmolar Concentration: The concentration of osmotically active particles in solution expressed in terms of osmoles of solute per liter of solution. Osmolality is expressed in terms of osmoles of solute per kilogram of solvent.Photogrammetry: Making measurements by the use of stereoscopic photographs.Plasma Membrane Calcium-Transporting ATPases: Calcium-transporting ATPases found on the PLASMA MEMBRANE that catalyze the active transport of CALCIUM from the CYTOPLASM into the extracellular space. They play a role in maintaining a CALCIUM gradient across plasma membrane.Amnion: The innermost membranous sac that surrounds and protects the developing embryo which is bathed in the AMNIOTIC FLUID. Amnion cells are secretory EPITHELIAL CELLS and contribute to the amniotic fluid.
Drin, Guillaume; Bruno, Antonny (3 May 2010). "Amphipathic helices and membrane curvature". FEBS Letters. 584 (9): 1840-1847. ... It is similar in structure to a transmembrane signal peptide and implies that it will anchor at the membrane by burying the ... The combination of poneratoxin binding to a cell membrane (in order to act upon a voltage-gated sodium channel) and the ... This is notable because of its structural similarity to other peptides that interact with the membrane, and indicates that ...
... s are a family of highly conserved membrane proteins that are important in creating membrane curvature. Epsins contribute ... Epsins may be the major membrane curvature-driving proteins in many clathrin-coated vesicle budding events. In addition to its ... Horvath CA, Vanden Broeck D, Boulet GA, Bogers J, De Wolf MJ (2007). "Epsin: inducing membrane curvature". The International ... The role of the ENTH domain is to bind membrane lipids which is currently thought to aid in the invagination of the plasma ...
Westphal CH, Chandra SS (January 2013). "Monomeric synucleins generate membrane curvature". The Journal of Biological Chemistry ... Experimental evidence has been collected on the interaction of alpha-synuclein with membrane and its involvement with membrane ... "Membrane curvature induction and tubulation are common features of synucleins and apolipoproteins". The Journal of Biological ... Monomeric α-synuclein is natively unfolded in solution but can also bind to membranes in an α-helical form. It seems likely ...
"Lipid Membrane Curvature Induced by Distearoyl Phosphatidylinositol 4-Phosphate". Soft Matter. 8: 3090-3093. doi:10.1039/ ... PtdIns4P is prevalent in the membrane of the Golgi apparatus. In the Golgi apparatus, PtdIns4P binds to the GTP-binding protein ... Choudhury RR, Hyvola N, Lowe M. Phosphoinositides and membrane traffic at the trans-Golgi network. Biochem Soc Symp. 2005;(72): ... This three molecule complex recruits proteins that need to be carried to the cell membrane. There is now evidence that PI-4-P ...
"A general amphipathic alpha-helical motif for sensing membrane curvature". Nature Structural & Molecular Biology. 14 (2): 138- ... Horchani H, de Saint-Jean M, Barelli H, Antonny B (2014). "Interaction of the Spo20 membrane-sensor motif with phosphatidic ... acid and other anionic lipids, and influence of the membrane environment". PLoS One. 9 (11): e113484. doi:10.1371/journal.pone. ...
Membrane nucleoporins are localized to the curvature of a nuclear pore. These proteins are embedded within the nuclear membrane ... The relationship of the membrane curvature of a nuclear pore with Y-complexes can be seen as analogous to the budding formation ... They span the membrane of the nuclear envelope and are often referred to as the scaffolding of a nuclear pore. Structural ... These three types are structural nucleoporins, membrane nucleoporins, and FG-nucleoporins. Structural nucleoporins form the ...
The roles of lysoPA, PA, and DAG in promoting membrane curvature do not preclude a role in recruiting proteins to the membrane ... the membrane while the surface headgroup remains unchanged. This can result in a more negative membrane curvature. Researchers ... The presence of two acyl chains but no headgroup results in a large negative curvature in membranes. The LPAAT BARS-50 has also ... For example, PA may be involved in vesicle formation by promoting membrane curvature and by recruiting the proteins to carry ...
subscription required) McMahon, H. T.; Gallop, J. L. (2005). "Membrane curvature and mechanisms of dynamic cell membrane ...
Additionally, it is thought that phosphatidylethanolamine regulates membrane curvature. Phosphatidylethanolamine is an ... Phosphatidylethanolamine produced in the mitochondrial membrane is also transported throughout the cell to other membranes for ... These products accelerate membrane lipid peroxidation, causing oxidative stress to cells that come in contact with them. ... It acts as a 'chaperone' to help the membrane proteins correctly fold their tertiary structures so that they can function ...
The BAR domain is banana shaped and binds to membrane via its concave face. It is capable of sensing membrane curvature by ... This helix inserts (like in the epsin ENTH domain) into the membrane and induces curvature, which is stabilised by the BAR ... June 2006). "Mechanism of endophilin N-BAR domain-mediated membrane curvature". EMBO J. 25 (12): 2898-910. doi:10.1038/sj.emboj ... June 2006). "Endophilin BAR domain drives membrane curvature by two newly identified structure-based mechanisms". EMBO J. 25 ( ...
The eyelids must be tight without revealing their mucous membrane. This dog has a serious penetrating, calm look about him. The ... The thorax consists of arched ribs with medium curvature; they are extended backwards enough to leave enough space for the ...
J. 17, 13 17 (1989). Curvature electric effect in black lipid membranes, A. G. Petrov, V. S. Sokolov, Eur. Biophys. J. 13, 139 ... Curvature electric effects in artificial and natural membranes studied using patch clamp techniques, A. G. Petrov, R. L. Ramsey ... converse flexoeffect of bilayer lipid membranes (1993); photoflexoeffect in photo-active membranes (1992 - 1994). Director of ... 98, 3076 3079 (1994) Flexoelectric effects in model and native membranes containing ion channels, A.G.Petrov, B.A.Miller, K. ...
In other tissues amphiphysin is likely involved in other membrane bending and curvature stabilization events. Amphiphysin has ... "BAR domains as sensors of membrane curvature: the amphiphysin BAR structure". Science. 303 (5657): 495-9. doi:10.1126/science. ... Amphiphysin is a brain-enriched protein with an N-terminal lipid interaction, dimerisation and membrane bending BAR domain, a ... Zhang B, Zelhof AC (July 2002). "Amphiphysins: raising the BAR for synaptic vesicle recycling and membrane dynamics. Bin- ...
The increased level of Retromer SNX-BARs causes a conformational switch to a curvature-inducing mode which initiates membrane ... SNX-BAR dimers which consist of SNX1 or SNX2 and SNX5 or SNX6 that facilitates endosomal membrane remodulation and curvature ... "Amphipathic motifs in BAR domains are essential for membrane curvature sensing". The EMBO Journal. 28 (21): 3303-14. doi: ... Although the SNX dimer is required for the recruitment of retromer to the endosomal membrane, the cargo binding function of ...
The membrane bilayer is not always flat. Local curvature of the membrane can be caused by the asymmetry and non-bilayer ... Curvature development is in constant flux and contributes to the dynamic nature of biological membranes. During the decade of ... Cell membrane proteins and glycoproteins do not exist as single elements of the lipid membrane, as first proposed by Singer and ... More dramatic and functional curvature is achieved through BAR domains, which bind to phosphatidylinositol on the membrane ...
Alpha-synuclein can damage membranes by inducing membrane curvature, and cause extensive tubulation and vesiculation when ... Extensive induction of membrane curvature is deleterious to the cell and would eventually lead to cell death.Apart from tubular ... October 2010). "Membrane curvature induction and tubulation are common features of synucleins and apolipoproteins". The Journal ... Membrane damage by alpha-synuclein could be another Parkinson's disease mechanism. The main known risk factor is age. ...
Alpha-synuclein can damage membranes by inducing membrane curvature,[12] and cause extensive tubulation and vesiculation when ... Extensive induction of membrane curvature is deleterious to the cell and would eventually lead to cell death.Apart from tubular ... Membrane damage[edit]. Damage to the membranes of organelles by monomeric or oligomeric proteins could also contribute to these ... "Membrane curvature induction and tubulation are common features of synucleins and apolipoproteins". The Journal of Biological ...
The corneal curvature has to remeasured and modified by history, central keratometry, or contact lens method. Sato, T (1939). " ... "Treatment of conical cornea (incision of Descemet's membrane)". Acta Soc Ophthalmol Jpn (in Japanese). 43: 544-55. Bashour M, ...
... whose small head group promotes membrane curvature. It is thus thought to facilitate membrane-vesicle fusion and fission in a ... PLD1 is a 120 kDa protein that is mainly located on the inner membranes of cells. It is primarily present at the Golgi complex ... Phosphatidic acid is a signal molecule and acts to recruit SK1 to membranes. PA is extremely short lived and is rapidly ... Upon the binding of an extracellular stimulus, PLD1 is transported to the plasma membrane. Basal PLD1 activity is low however, ...
Masuda M, Takeda S, Sone M, Ohki T, Mori H, Kamioka Y, Mochizuki N (2006). "Endophilin BAR domain drives membrane curvature by ... a brain-specific membrane-associated lysophosphatidic acid acyl transferase with properties distinct from endophilin A1". J. ...
Doucet CM, Esmery N, de Saint-Jean M, Antonny B (2015). "Membrane Curvature Sensing by Amphipathic Helices Is Modulated by the ... Most are peripheral membrane proteins attached at one end to Golgi membranes. They have flexible regions between the coiled- ... Drin G, Morello V, Casella JF, Gounon P, Antonny B (2008). "Asymmetric tethering of flat and curved lipid membranes by a golgin ... "Golgins associate with Golgi membranes in a variety of ways". ars.els-cdn.com/. Biochimica et Biophysica Acta (BBA) - Molecular ...
... or curvature of the membrane. Mechanosensitive channels respond to membrane tension by altering their conformation between an ... It has been demonstrated that the tension/stretch profile in the lipid bilayer is originated by membrane curvature and bilayer- ... During gating the major processes that account for this event are: hydrophobic mismatch, and membrane curvature. It has been ... The contribution of membrane deformation in the gating of MS channels can be divided in two types: the deformation of the plane ...
... a dimerizing and membrane recruitment module that effects membrane curvature". Structure. 15 (7): 839-52. doi:10.1016/j.str. ...
The aggregation of daptomycin alters the curvature of the membrane, which creates holes that leak ions. This causes rapid ... UMich Orientation of Proteins in Membranes families/superfamily-172 - Orientations of daptomycin and tsushimycin in membrane. ... Daptomycin has a distinct mechanism of action, disrupting multiple aspects of bacterial cell membrane function. It inserts into ... "Daptomycin-Mediated Reorganization of Membrane Architecture Causes Mislocalization of Essential Cell Division Proteins". ...
2004). "Sorting nexin-1 mediates tubular endosome-to-TGN transport through coincidence sensing of high- curvature membranes and ...
The skelion will bind to other ones attached to the membrane to form a polyhedral lattice, skelion, which pulls the membrane ... Ford MG, Mills IG, Peter BJ, Vallis Y, Praefcke GJ, Evans PR, McMahon HT (September 2002). "Curvature of clathrin-coated pits ... It recruits clathrin to membranes and also promotes its polymerization. Epsin also recruits clathrin to membranes and promotes ... linking one of its three feet to the membrane at a time. Clathrin cannot bind to membrane or cargo directly and instead uses ...
... usually involving the membrane (tunica albuginea) surrounding the erectile tissue (corpus cavernosum penis). This may ... Lateral curvature of the penis during Erection. *Penis flail distal to lesion ...
However, the influence of geometrical membrane curvature on GPCR sorting remains unknown. Here we used fluorescence imaging to ... Curvature-dependent sorting was regulated by ligands in a specific manner. We anticipate that this curvature-dependent ... to the data enabled us to quantify how sorting is mediated by an energetic drive to match receptor shape and membrane curvature ... modeling suggests that this is due to an energetic drive to match receptor shape and elasticity to membrane curvature. The ...
Membrane curvature is the geometrical measure or characterization of the curvature of membranes. The membranes can be naturally ... Perhaps the most simple and intuitive driving force in membrane curvature is the natural spontaneous curvature exhibited by ... Upon binding, the membranes curvature is increased by the rigid domain. One more case of protein interaction that induces and/ ... Even though often membrane curvature is thought to be a completely spontaneous process, thermodynamically speaking there must ...
In WT cells, Tcbs generate membrane peaks of extreme curvature on the cER membrane. This may facilitate the extraction of cER ... Tricalbin-Mediated Contact Sites Control ER Curvature to Maintain Plasma Membrane Integrity.. Collado J1, Kalemanov M2, Campelo ... F) Enhancement of the rate of lipid extraction by membrane curvature according to a theoretical model. The plot shows the rate ... ER peaks were also present at other MCS, implying that membrane curvature enforcement may be a widespread mechanism to regulate ...
Membrane remodelling plays an important role in cellular tasks such as endocytosis, vesiculation and protein sorting, and in ... Aggregation and vesiculation of membrane proteins by curvature-mediated interactions Nature. 2007 May 24;447(7143):461-4. doi: ... Here we use coarse-grained membrane simulations to show that curvature-inducing model proteins adsorbed on lipid bilayer ... membranes can experience attractive interactions that arise purely as a result of membrane curvature. We find that once a ...
Membrane Proteins of the Endoplasmic Reticulum Induce High-Curvature Tubules. By Junjie Hu, Yoko Shibata, Christiane Voss, Tom ... Membrane Proteins of the Endoplasmic Reticulum Induce High-Curvature Tubules. By Junjie Hu, Yoko Shibata, Christiane Voss, Tom ... Membrane Proteins of the Endoplasmic Reticulum Induce High-Curvature Tubules Message Subject. (Your Name) has forwarded a page ... Integral membrane proteins from the endoplasmic reticulum induce the development of tubular structures in vitro by forming ...
Plasma Membrane MCC/Eisosome Domains Promote Stress Resistance in Fungi There is growing appreciation that the plasma membrane ... Studies with the budding yeast Saccharomyces cerevisiae have identified a novel type of plasma membrane domain known as the MCC ...
One feature of membranes that affects lipid domain formation is membrane curvature. To directly test the role of curvature in ... using a supported lipid bilayer that was assembled over a nanopatterned surface to obtain regions of membrane curvature. Both ... the dynamics of single molecules of biotinylated DHPE was also affected by membrane curvature and highly confined motion was ... The accumulation of lipids at curvatures ranging from 28 nm to 55 nm radii was measured and fluorescein labeled DHPE ...
Proteins embedded in soft biological membranes experience a long-range force mediated by elastic curvature deformations. The ... Revisiting the curvature-mediated interactions between proteins in biological membranes H. Agrawal, L. Liu and P. Sharma, Soft ... Proteins embedded in soft biological membranes experience a long-range force mediated by elastic curvature deformations. The ... We modify the classical Helfrich-Canham theory of curvature elasticity to incorporate protein-membrane specificity, discuss the ...
Myosin IIA interacts with the spectrin-actin membrane skeleton to control red blood cell membrane curvature and deformability. ... Myosin IIA interacts with the spectrin-actin membrane skeleton to control red blood cell membrane curvature and deformability ... Myosin IIA interacts with the spectrin-actin membrane skeleton to control red blood cell membrane curvature and deformability ... Myosin IIA interacts with the spectrin-actin membrane skeleton to control red blood cell membrane curvature and deformability ...
... we predicted that NMIIA contractility maintains membrane curvature by promoting membrane tension and reducing local membrane ... Myosin IIA interacts with the spectrin-actin membrane skeleton to control red blood cell membrane curvature and deformability. ... Myosin IIA interacts with the spectrin-actin membrane skeleton to control red blood cell membrane curvature and deformability ... Myosin IIA interacts with the spectrin-actin membrane skeleton to control red blood cell membrane curvature and deformability ...
... membrane curvature.. In many cases, these curves are rather "tight": imagine a vesicle budding from the plasma membrane into ... The long and short of membrane curvature sensing by septins. View ORCID ProfileMichael A. McMurray Correspondence email ... Cells and organelles, on the other hand, are rarely spherical, due in part to local changes in membrane curvature resulting ... Septin proteins form hetero-oligomers that associate with membranes of specific curvatures, but the mechanism is unknown. In ...
We introduce a model for the binding and unbinding of curvature inducing proteins on vesicles using Dynamic Triangulation Monte ... The ability of proteins to sense and/or generate membrane curvature is crucial for many biological processes inside the cell. ... Our results show that at low μ values, proteins only sense membrane curvature, whereas at high μ values, they induce curvature ... Transition from curvature sensing to generation in a vesicle driven by protein binding strength and membrane tension ...
Current model membrane approaches studying curvature sensing are limited to positive curvatures and often involve complex ... Curvature Sorting of Peripheral Proteins on Solid-Supported Wavy Membranes. Tobias Baumgart and Shu Yang ... Surface topography and curvatures measured via AFM (left), Lipids and peripheral proteins on wavy membranes imaged via epi- ... The deformation of cell membranes couples with spatial distributions of membrane proteins and lipids. ...
IRSp53 senses negative membrane curvature and phase separates along membrane tubules. Prévost C, Zhao H, Manzi J, Lemichez E, ... Our results demonstrate that I-BAR dimers sense negative membrane curvature. Experiment and theory reveal that the I-BAR ... The inverted-BAR (I-BAR) protein IRSp53, for instance, is found on the inner leaflet of the tubular membrane of filopodia; ... This peculiar behaviour is due to the shallow intrinsic curvature of I-BAR dimers. It allows constriction of weakly curved ...
We review the background behind the notions of spontaneous and intrinsic curvatures of lipid membranes with a goal to make ... Membrane bending elasticity Spontaneous curvature Intrinsic curvature Bending modulus This is a preview of subscription content ... McMahon HT, Boucrot E (2015) Membrane curvature at a glance. J Cell Sci 128:1065-1070CrossRefGoogle Scholar ... Zimmerberg J, Kozlov MM (2006) How proteins produce cellular membrane curvature. Nat Rev Mol Cell Biol 7:9-19CrossRefGoogle ...
Taken together, these results imply that the influenza HA fusion peptide can have substantial effects on the membrane curvature ... and DPPC/PA showed a positive curvature-inducing effect, whereas WT20 showed a negative curvature-inducing effect on a DPPC ... as reported previously for different membranes. Simulations of WT20 embedded in bilayer membranes made up of dioleoylphos- ... Its movability and oblique orientation appear to be associated with its ability to perturb membrane/water interfaces. ...
... that through coincidence detection SNX1 associates with a microdomain of the early endosome-characterized by high membrane ... curvature and the presence of 3-phosphoinositides-from where it regulates tubular-based endosome-to-TGN retrieval of the CI-MPR ... a membrane binding domain that endows SNX1 with the ability to form dimers and to sense membrane curvature. We present evidence ... Sorting nexin-1 Mediates Tubular endosome-to-TGN Transport Through Coincidence Sensing of High- Curvature Membranes and 3- ...
Testing the hypothesis that amphiphilic antineoplastic lipid analogues act through reduction of membrane curvature elastic ... Testing the hypothesis that amphiphilic antineoplastic lipid analogues act through reduction of membrane curvature elastic ... Testing the hypothesis that amphiphilic antineoplastic lipid analogues act through reduction of membrane curvature elastic ... Testing the hypothesis that amphiphilic antineoplastic lipid analogues act through reduction of membrane curvature elastic ...
Thylakoid Membrane Architecture in Synechocystis Depends on CurT, a Homolog of the Granal CURVATURE THYLAKOID1 Proteins. ... CurT induces membrane curvature in vitro and is distributed all over the thylakoids, with local concentrations at biogenesis ... Thylakoid Membrane Architecture in Synechocystis Depends on CurT, a Homolog of the Granal CURVATURE THYLAKOID1 Proteins ... The initial steps in photosystem II (PSII) assembly are thought to take place in these regions, which contain a membrane ...
Seminars and Events at the Research Institute of Molecular Pathology (IMP) and Vienna Biocenter (VBC).
2014). Understanding the membrane biophysics of alpha-Synuclein and its role in membrane curvature induction and structural ... In addition, numerous biophysical studies have identified potential curvature sensing and curvature inducing characteristics ... through a relief of curvature stress (surface tension) inherent to the highly curved membrane. ... Using a novel set of analysis algorithms we show that binding of aSyn to lipid bilayers thins the membrane and induces a ...
... and move along the direction of greatest membrane curvature, thus orienting the insertion of new glycan strands around the cell ... MreB filaments align along greatest principal membrane curvature to orient cell wall synthesis. ... Figure 2-figure supplement 1B - Mean curvature of cell contours (curvature) and the median track angle (angle) over time during ... A) The negative curvature of MreB filaments (arrowheads) aligns with the negative principal curvature of the liposome surface ( ...
Impact of abnormal sterol expression on membrane curvature. (A) Membrane bending rigidity KC obtained from measured ... In addition to changes in bending rigidity, the elastic energy owing to curvature of the membrane also changed by 1.2 and 1.8 ... Rand, P., Fuller, N. L., Gruner, S. M. and Parsegian, V. A. (1990). Membrane curvature, lipid segregation. and structural ... These findings clearly demonstrate that cholesterol is essential for conferring the rigidity necessary for membrane curvature ...
An amphipathic helix enables septins to sense micrometer-scale membrane curvature. Septins sense curvature using an amphipathic ... The long and short of membrane curvature sensing by septins Michael A. McMurray 0000-0002-4615-4334 ... Michael A. McMurray; The long and short of membrane curvature sensing by septins. J Cell Biol 1 April 2019; 218 (4): 1083-1085 ... Cells and organelles, on the other hand, are rarely spherical, due in part to local changes in membrane curvature resulting ...
  • Leikin S, Kozlov MM, Fuller NL, Rand RP (1996) Measured effects of diacylglycerol on structural and elastic properties of phospholipid membranes. (springer.com)
  • However, thermal fluctuations in thin elastic membranes fundamentally alter the long-wavelength physics. (anl.gov)
  • Thermalized elastic membranes can undergo a crumpling transition when the microscopic bending stiffness is comparable to kT. (anl.gov)
  • An elastic membrane stretched between two walls takes a shape defined by its length and the volume of fluid it encloses. (royalsocietypublishing.org)
  • Here, the two-dimensional shape of an elastic membrane in a 'confining' box is studied by introducing a repulsive confinement pressure that prevents the membrane from intersecting the wall. (royalsocietypublishing.org)
  • As shown in figure 1 , the inner membrane behaves like a closed elastic sheet that deforms as a two-dimensional object. (royalsocietypublishing.org)
  • In unconfined geometries, the shape of surface wrinkles may be computed using any number of mathematical techniques, such as elastic rod theory or by considering a fluid-structure interaction problem of a periodic, length-preserving bilipid membrane modelled by the Helfrich energy immersed in a viscous fluid [ 17 ]. (royalsocietypublishing.org)
  • These results provide quantitative evidence for the influence of steric pressure on the content and assembly of curved cellular membrane structures. (utmb.edu)
  • Even though often membrane curvature is thought to be a completely spontaneous process, thermodynamically speaking there must be factors actuating as the driving force for curvature to exist. (wikipedia.org)
  • More dramatically, the spontaneous formation of many membrane nanotubes protruding into the interior vesicle compartment reveals a substantial asymmetry and spontaneous curvature of the membrane segments in contact with the PEG-rich phase, arising from the asymmetric adsorption of polymer molecules onto the two leaflets of the bilayers. (frontiersin.org)
  • I will demonstrate these aspects using two specific problems: (i) estimating the excess area in a cell membrane through the extraction of tethers, and (ii) atomistic to thermodynamic descriptions of the spontaneous membrane remodeling activity of ENTH and Exo70 domain containing proteins. (tifr.res.in)
  • It causes fast rupture of the bacterial model membrane (POPG-rich) at concentrations 100-fold lower than that required for the disruption of mammalian model membranes (POPC-rich). (fapesp.br)
  • The Gladfelter laboratory previously noticed that in a related fungus, Ashbya gossypii , septins localize to membrane regions of a narrow range of positive curvatures where filamentous Ashbya cells make "branches" ( 3 ). (rupress.org)
  • Current model membrane approaches studying curvature sensing are limited to positive curvatures and often involve complex setups. (upenn.edu)
  • Cells and organelles, on the other hand, are rarely spherical, due in part to local changes in membrane curvature resulting from distinct lipid compositions in the two layers and/or to the influence of membrane-associated proteins. (rupress.org)
  • We show finally that thin amorphous spherical shells with a background Gaussian curvature are inevitably (in the absence of a stabilizing pressure difference) crushed by thermal fluctuations beyond a critical size, of order 160 nm for graphene at room temperature. (anl.gov)
  • We find that BAR domains bind strongly through the maximum curvature surface and, additionally, at an orientation that presents a lesser degree of curvature, thus enabling N-BAR domains to induce a range of local curvatures. (qxmd.com)
  • A 20 amino acid peptide from the N-terminus of the influenza HA fusion peptide (WT20) assumed the oblique orientation at the interface between water and the membrane made up of dipalmitoylphosphatidylcholine (DPPC)/palmitic acid (PA), as reported previously for different membranes. (scirp.org)
  • Taken together, these results imply that the influenza HA fusion peptide can have substantial effects on the membrane curvature and can assume a wide range of orientation/position in membranes depending on the local environment of the lipid/water system. (scirp.org)