Membrane Proteins: Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.Cell Membrane: The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.Bacterial Outer Membrane Proteins: Proteins isolated from the outer membrane of Gram-negative bacteria.Membranes: Thin layers of tissue which cover parts of the body, separate adjacent cavities, or connect adjacent structures.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.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.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).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.Erythrocyte Membrane: The semi-permeable outer structure of a red blood cell. It is known as a red cell 'ghost' after HEMOLYSIS.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.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.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.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.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.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.Lipid Bilayers: Layers of lipid molecules which are two molecules thick. Bilayer systems are frequently studied as models of biological membranes.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.Membrane Glycoproteins: Glycoproteins found on the membrane or surface of cells.Bacterial Proteins: Proteins found in any species of bacterium.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.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.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.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.Cell Line: Established cell cultures that have the potential to propagate indefinitely.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)Carrier Proteins: Transport proteins that carry specific substances in the blood or across cell membranes.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.Molecular Weight: The sum of the weight of all the atoms in a molecule.Viral Matrix Proteins: Proteins associated with the inner surface of the lipid bilayer of the viral envelope. These proteins have been implicated in control of viral transcription and may possibly serve as the "glue" that binds the nucleocapsid to the appropriate membrane site during viral budding from the host cell.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.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)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.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).Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Escherichia coli Proteins: Proteins obtained from ESCHERICHIA COLI.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.Cell Fractionation: Techniques to partition various components of the cell into SUBCELLULAR FRACTIONS.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).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.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.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.Models, Molecular: Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.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)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.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.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.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.Protein Sorting Signals: Amino acid sequences found in transported proteins that selectively guide the distribution of the proteins to specific cellular compartments.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)Recombinant Proteins: Proteins prepared by recombinant DNA technology.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.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)Binding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.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)Lysosome-Associated Membrane Glycoproteins: Ubiquitously expressed integral membrane glycoproteins found in the LYSOSOME.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.Erythrocytes: Red blood cells. Mature erythrocytes are non-nucleated, biconcave disks containing HEMOGLOBIN whose function is to transport OXYGEN.Endocytosis: Cellular uptake of extracellular materials within membrane-limited vacuoles or microvesicles. ENDOSOMES play a central role in endocytosis.Kinetics: The rate dynamics in chemical or physical systems.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.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.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.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.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.Hydrophobic and Hydrophilic Interactions: The thermodynamic interaction between a substance and WATER.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.Endosomes: Cytoplasmic vesicles formed when COATED VESICLES shed their CLATHRIN coat. Endosomes internalize macromolecules bound by receptors on the cell surface.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.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.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.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.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.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)Bacteriorhodopsins: Rhodopsins found in the PURPLE MEMBRANE of halophilic archaea such as HALOBACTERIUM HALOBIUM. Bacteriorhodopsins function as an energy transducers, converting light energy into electrochemical energy via PROTON PUMPS.Vacuoles: Any spaces or cavities within a cell. They may function in digestion, storage, secretion, or excretion.Cricetinae: A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.Biological Transport, Active: The movement of materials across cell membranes and epithelial layers against an electrochemical gradient, requiring the expenditure of metabolic energy.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.Microvilli: Minute projections of cell membranes which greatly increase the surface area of the cell.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.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.Sequence Alignment: The arrangement of two or more amino acid or base sequences from an organism or organisms in such a way as to align areas of the sequences sharing common properties. The degree of relatedness or homology between the sequences is predicted computationally or statistically based on weights assigned to the elements aligned between the sequences. This in turn can serve as a potential indicator of the genetic relatedness between the organisms.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.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.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.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.Protein Folding: Processes involved in the formation of TERTIARY PROTEIN STRUCTURE.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.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.Anion Exchange Protein 1, Erythrocyte: A major integral transmembrane protein of the ERYTHROCYTE MEMBRANE. It is the anion exchanger responsible for electroneutral transporting in CHLORIDE IONS in exchange of BICARBONATE IONS allowing CO2 uptake and transport from tissues to lungs by the red blood cells. Genetic mutations that result in a loss of the protein function have been associated with type 4 HEREDITARY SPHEROCYTOSIS.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)Time Factors: Elements of limited time intervals, contributing to particular results or situations.Cytosol: Intracellular fluid from the cytoplasm after removal of ORGANELLES and other insoluble cytoplasmic components.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)Nuclear Envelope: The membrane system of the CELL NUCLEUS that surrounds the nucleoplasm. It consists of two concentric membranes separated by the perinuclear space. The structures of the envelope where it opens to the cytoplasm are called the nuclear pores (NUCLEAR PORE).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)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.Antibodies, Monoclonal: Antibodies produced by a single clone of cells.Cell Membrane Structures: Structures which are part of the CELL MEMBRANE or have cell membrane as a major part of their structure.Genes, Bacterial: The functional hereditary units of BACTERIA.Exocytosis: Cellular release of material within membrane-limited vesicles by fusion of the vesicles with the CELL MEMBRANE.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.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.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.Biological Transport: The movement of materials (including biochemical substances and drugs) through a biological system at the cellular level. The transport can be across cell membranes and epithelial layers. It also can occur within intracellular compartments and extracellular compartments.Glycosylation: The chemical or biochemical addition of carbohydrate or glycosyl groups to other chemicals, especially peptides or proteins. Glycosyl transferases are used in this biochemical reaction.Glycoproteins: Conjugated protein-carbohydrate compounds including mucins, mucoid, and amyloid glycoproteins.Lysosomal-Associated Membrane Protein 2: An abundant lysosomal-associated membrane protein that has been found to shuttle between LYSOSOMES; ENDOSOMES; and the PLASMA MEMBRANE. Loss of expression of lysosomal-associated membrane protein 2 is associated with GLYCOGEN STORAGE DISEASE TYPE IIB.Proteolipids: Protein-lipid combinations abundant in brain tissue, but also present in a wide variety of animal and plant tissues. In contrast to lipoproteins, they are insoluble in water, but soluble in a chloroform-methanol mixture. The protein moiety has a high content of hydrophobic amino acids. The associated lipids consist of a mixture of GLYCEROPHOSPHATES; CEREBROSIDES; and SULFOGLYCOSPHINGOLIPIDS; while lipoproteins contain PHOSPHOLIPIDS; CHOLESTEROL; and TRIGLYCERIDES.Fungal Proteins: Proteins found in any species of fungus.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.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).)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.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.Peptide Fragments: Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.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)Glycosylphosphatidylinositols: Compounds containing carbohydrate or glycosyl groups linked to phosphatidylinositols. They anchor GPI-LINKED PROTEINS or polysaccharides to cell membranes.Antigens, Bacterial: Substances elaborated by bacteria that have antigenic activity.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.Vesicle-Associated Membrane Protein 2: A synaptic membrane protein involved in MEMBRANE FUSION of SYNAPTIC VESICLES with the presynaptic membranes. It is the prototype member of the R-SNARE PROTEINS.Herpesvirus 4, Human: The type species of LYMPHOCRYPTOVIRUS, subfamily GAMMAHERPESVIRINAE, infecting B-cells in humans. It is thought to be the causative agent of INFECTIOUS MONONUCLEOSIS and is strongly associated with oral hairy leukoplakia (LEUKOPLAKIA, HAIRY;), BURKITT LYMPHOMA; and other malignancies.Spectrin: A high molecular weight (220-250 kDa) water-soluble protein which can be extracted from erythrocyte ghosts in low ionic strength buffers. The protein contains no lipids or carbohydrates, is the predominant species of peripheral erythrocyte membrane proteins, and exists as a fibrous coating on the inner, cytoplasmic surface of the membrane.Organelles: Specific particles of membrane-bound organized living substances present in eukaryotic cells, such as the MITOCHONDRIA; the GOLGI APPARATUS; ENDOPLASMIC RETICULUM; LYSOSOMES; PLASTIDS; and VACUOLES.Antibodies, Bacterial: Immunoglobulins produced in a response to BACTERIAL ANTIGENS.Periplasm: The space between the inner and outer membranes of a cell that is shared with the cell wall.Sodium: A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23.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.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.Proteins: 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.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.Qa-SNARE Proteins: A subfamily of Q-SNARE PROTEINS which occupy the same position as syntaxin 1A in the SNARE complex and which also are most similar to syntaxin 1A in their AMINO ACID SEQUENCE. This subfamily is also known as the syntaxins, although a few so called syntaxins are Qc-SNARES.Monosaccharide Transport Proteins: A large group of membrane transport proteins that shuttle MONOSACCHARIDES across CELL MEMBRANES.RNA, Messenger: RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.ATP-Binding Cassette Transporters: A family of MEMBRANE TRANSPORT PROTEINS that require ATP hydrolysis for the transport of substrates across membranes. The protein family derives its name from the ATP-binding domain found on the protein.Permeability: Property of membranes and other structures to permit passage of light, heat, gases, liquids, metabolites, and mineral ions.R-SNARE Proteins: SNARE proteins where the central amino acid residue of the SNARE motif is an ARGININE. They are classified separately from the Q-SNARE PROTEINS where the central amino acid residue of the SNARE motif is a GLUTAMINE. This subfamily contains the vesicle associated membrane proteins (VAMPs) based on similarity to the prototype for the R-SNAREs, VAMP2 (synaptobrevin 2).Cholesterol: The principal sterol of all higher animals, distributed in body tissues, especially the brain and spinal cord, and in animal fats and oils.Luminescent Proteins: Proteins which are involved in the phenomenon of light emission in living systems. Included are the "enzymatic" and "non-enzymatic" types of system with or without the presence of oxygen or co-factors.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.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.Trypsin: A serine endopeptidase that is formed from TRYPSINOGEN in the pancreas. It is converted into its active form by ENTEROPEPTIDASE in the small intestine. It catalyzes hydrolysis of the carboxyl group of either arginine or lysine. EC 3.4.21.4.Spectrometry, Fluorescence: Measurement of the intensity and quality of fluorescence.Mutagenesis, Site-Directed: Genetically engineered MUTAGENESIS at a specific site in the DNA molecule that introduces a base substitution, or an insertion or deletion.Nerve Tissue ProteinsDNA, Complementary: Single-stranded complementary DNA synthesized from an RNA template by the action of RNA-dependent DNA polymerase. cDNA (i.e., complementary DNA, not circular DNA, not C-DNA) is used in a variety of molecular cloning experiments as well as serving as a specific hybridization probe.Electric Conductivity: The ability of a substrate to allow the passage of ELECTRONS.Amino Acid Motifs: Commonly observed structural components of proteins formed by simple combinations of adjacent secondary structures. A commonly observed structure may be composed of a CONSERVED SEQUENCE which can be represented by a CONSENSUS SEQUENCE.Mitochondrial Membrane Transport Proteins: Proteins involved in the transport of specific substances across the membranes of the MITOCHONDRIA.Epitopes: Sites on an antigen that interact with specific antibodies.Antigens, Surface: Antigens on surfaces of cells, including infectious or foreign cells or viruses. They are usually protein-containing groups on cell membranes or walls and may be isolated.Cross-Linking Reagents: Reagents with two reactive groups, usually at opposite ends of the molecule, that are capable of reacting with and thereby forming bridges between side chains of amino acids in proteins; the locations of naturally reactive areas within proteins can thereby be identified; may also be used for other macromolecules, like glycoproteins, nucleic acids, or other.Epithelial Cells: Cells that line the inner and outer surfaces of the body by forming cellular layers (EPITHELIUM) or masses. Epithelial cells lining the SKIN; the MOUTH; the NOSE; and the ANAL CANAL derive from ectoderm; those lining the RESPIRATORY SYSTEM and the DIGESTIVE SYSTEM derive from endoderm; others (CARDIOVASCULAR SYSTEM and LYMPHATIC SYSTEM) derive from mesoderm. Epithelial cells can be classified mainly by cell shape and function into squamous, glandular and transitional epithelial cells.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)Aquaporins: A class of porins that allow the passage of WATER and other small molecules across CELL MEMBRANES.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)Precipitin Tests: Serologic tests in which a positive reaction manifested by visible CHEMICAL PRECIPITATION occurs when a soluble ANTIGEN reacts with its precipitins, i.e., ANTIBODIES that can form a precipitate.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.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.DNA Primers: Short sequences (generally about 10 base pairs) of DNA that are complementary to sequences of messenger RNA and allow reverse transcriptases to start copying the adjacent sequences of mRNA. Primers are used extensively in genetic and molecular biology techniques.Gene Expression: The phenotypic manifestation of a gene or genes by the processes of GENETIC TRANSCRIPTION and GENETIC TRANSLATION.Cytoskeleton: The network of filaments, tubules, and interconnecting filamentous bridges which give shape, structure, and organization to the cytoplasm.Cytoplasmic Granules: Condensed areas of cellular material that may be bounded by a membrane.Mitochondrial Proteins: Proteins encoded by the mitochondrial genome or proteins encoded by the nuclear genome that are imported to and resident in the MITOCHONDRIA.Immunohistochemistry: Histochemical localization of immunoreactive substances using labeled antibodies as reagents.Endopeptidases: A subclass of PEPTIDE HYDROLASES that catalyze the internal cleavage of PEPTIDES or PROTEINS.Glycophorin: The major sialoglycoprotein of the human erythrocyte membrane. It consists of at least two sialoglycopeptides and is composed of 60% carbohydrate including sialic acid and 40% protein. It is involved in a number of different biological activities including the binding of MN blood groups, influenza viruses, kidney bean phytohemagglutinin, and wheat germ agglutinin.Gene Expression Regulation, Bacterial: Any of the processes by which cytoplasmic or intercellular factors influence the differential control of gene action in bacteria.Surface-Active Agents: Agents that modify interfacial tension of water; usually substances that have one lipophilic and one hydrophilic group in the molecule; includes soaps, detergents, emulsifiers, dispersing and wetting agents, and several groups of antiseptics.Crystallization: The formation of crystalline substances from solutions or melts. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Centrifugation, Density Gradient: Separation of particles according to density by employing a gradient of varying densities. At equilibrium each particle settles in the gradient at a point equal to its density. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Protein PrecursorsCrystallography, X-Ray: The study of crystal structure using X-RAY DIFFRACTION techniques. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Nuclear Magnetic Resonance, Biomolecular: NMR spectroscopy on small- to medium-size biological macromolecules. This is often used for structural investigation of proteins and nucleic acids, and often involves more than one isotope.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.Amino Acids: Organic compounds that generally contain an amino (-NH2) and a carboxyl (-COOH) group. Twenty alpha-amino acids are the subunits which are polymerized to form proteins.Proton-Translocating ATPases: Multisubunit enzymes that reversibly synthesize ADENOSINE TRIPHOSPHATE. They are coupled to the transport of protons across a membrane.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.Unilamellar Liposomes: Single membrane vesicles, generally made of PHOSPHOLIPIDS.Kidney: Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.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).Brefeldin A: A fungal metabolite which is a macrocyclic lactone exhibiting a wide range of antibiotic activity.Liver: A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.Antibodies: Immunoglobulin molecules having a specific amino acid sequence by virtue of which they interact only with the ANTIGEN (or a very similar shape) that induced their synthesis in cells of the lymphoid series (especially PLASMA CELLS).Sodium Dodecyl Sulfate: An anionic surfactant, usually a mixture of sodium alkyl sulfates, mainly the lauryl; lowers surface tension of aqueous solutions; used as fat emulsifier, wetting agent, detergent in cosmetics, pharmaceuticals and toothpastes; also as research tool in protein biochemistry.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.Saccharomyces cerevisiae: A species of the genus SACCHAROMYCES, family Saccharomycetaceae, order Saccharomycetales, known as "baker's" or "brewer's" yeast. The dried form is used as a dietary supplement.Sodium-Potassium-Exchanging ATPase: An enzyme that catalyzes the active transport system of sodium and potassium ions across the cell wall. Sodium and potassium ions are closely coupled with membrane ATPase which undergoes phosphorylation and dephosphorylation, thereby providing energy for transport of these ions against concentration gradients.Species Specificity: The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.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)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.Alkaline Phosphatase: An enzyme that catalyzes the conversion of an orthophosphoric monoester and water to an alcohol and orthophosphate. EC 3.1.3.1.Blood Proteins: Proteins that are present in blood serum, including SERUM ALBUMIN; BLOOD COAGULATION FACTORS; and many other types of proteins.Vesicular Transport Proteins: A broad category of proteins involved in the formation, transport and dissolution of TRANSPORT VESICLES. They play a role in the intracellular transport of molecules contained within membrane vesicles. Vesicular transport proteins are distinguished from MEMBRANE TRANSPORT PROTEINS, which move molecules across membranes, by the mode in which the molecules are transported.Ankyrins: A family of membrane-associated proteins responsible for the attachment of the cytoskeleton. Erythrocyte-related isoforms of ankyrin attach the SPECTRIN cytoskeleton to a transmembrane protein (ANION EXCHANGE PROTEIN 1, ERYTHROCYTE) in the erythrocyte plasma membrane. Brain-related isoforms of ankyrin also exist.Gene Deletion: A genetic rearrangement through loss of segments of DNA or RNA, bringing sequences which are normally separated into close proximity. This deletion may be detected using cytogenetic techniques and can also be inferred from the phenotype, indicating a deletion at one specific locus.GTP-Binding Proteins: Regulatory proteins that act as molecular switches. They control a wide range of biological processes including: receptor signaling, intracellular signal transduction pathways, and protein synthesis. Their activity is regulated by factors that control their ability to bind to and hydrolyze GTP to GDP. EC 3.6.1.-.Phenotype: The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.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.

Membrane-tethered Drosophila Armadillo cannot transduce Wingless signal on its own. (1/57141)

Drosophila Armadillo and its vertebrate homolog beta-catenin are key effectors of Wingless/Wnt signaling. In the current model, Wingless/Wnt signal stabilizes Armadillo/beta-catenin, which then accumulates in nuclei and binds TCF/LEF family proteins, forming bipartite transcription factors which activate transcription of Wingless/Wnt responsive genes. This model was recently challenged. Overexpression in Xenopus of membrane-tethered beta-catenin or its paralog plakoglobin activates Wnt signaling, suggesting that nuclear localization of Armadillo/beta-catenin is not essential for signaling. Tethered plakoglobin or beta-catenin might signal on their own or might act indirectly by elevating levels of endogenous beta-catenin. We tested these hypotheses in Drosophila by removing endogenous Armadillo. We generated a series of mutant Armadillo proteins with altered intracellular localizations, and expressed these in wild-type and armadillo mutant backgrounds. We found that membrane-tethered Armadillo cannot signal on its own; however it can function in adherens junctions. We also created mutant forms of Armadillo carrying heterologous nuclear localization or nuclear export signals. Although these signals alter the subcellular localization of Arm when overexpressed in Xenopus, in Drosophila they have little effect on localization and only subtle effects on signaling. This supports a model in which Armadillo's nuclear localization is key for signaling, but in which Armadillo intracellular localization is controlled by the availability and affinity of its binding partners.  (+info)

Membrane fusion: structure snared at last. (2/57141)

The structure of the core of the neuronal 'SNARE complex', involved in neurotransmitter release, has been determined recently. Its topological similarity to viral fusion proteins suggests how the SNARE complex might facilitate membrane fusion.  (+info)

The hematopoietic-specific adaptor protein gads functions in T-cell signaling via interactions with the SLP-76 and LAT adaptors. (3/57141)

BACKGROUND: The adaptor protein Gads is a Grb2-related protein originally identified on the basis of its interaction with the tyrosine-phosphorylated form of the docking protein Shc. Gads protein expression is restricted to hematopoietic tissues and cell lines. Gads contains a Src homology 2 (SH2) domain, which has previously been shown to have a similar binding specificity to that of Grb2. Gads also possesses two SH3 domains, but these have a distinct binding specificity to those of Grb2, as Gads does not bind to known Grb2 SH3 domain targets. Here, we investigated whether Gads is involved in T-cell signaling. RESULTS: We found that Gads is highly expressed in T cells and that the SLP-76 adaptor protein is a major Gads-associated protein in vivo. The constitutive interaction between Gads and SLP-76 was mediated by the carboxy-terminal SH3 domain of Gads and a 20 amino-acid proline-rich region in SLP-76. Gads also coimmunoprecipitated the tyrosine-phosphorylated form of the linker for activated T cells (LAT) adaptor protein following cross-linking of the T-cell receptor; this interaction was mediated by the Gads SH2 domain. Overexpression of Gads and SLP-76 resulted in a synergistic augmentation of T-cell signaling, as measured by activation of nuclear factor of activated T cells (NFAT), and this cooperation required a functional Gads SH2 domain. CONCLUSIONS: These results demonstrate that Gads plays an important role in T-cell signaling via its association with SLP-76 and LAT. Gads may promote cross-talk between the LAT and SLP-76 signaling complexes, thereby coupling membrane-proximal events to downstream signaling pathways.  (+info)

Sonic hedgehog signaling by the patched-smoothened receptor complex. (4/57141)

BACKGROUND: The Hedgehog (Hh) family of secreted proteins is involved in a number of developmental processes as well as in cancer. Genetic and biochemical data suggest that the Sonic hedgehog (Shh) receptor is composed of at least two proteins: the tumor suppressor protein Patched (Ptc) and the seven-transmembrane protein Smoothened (Smo). RESULTS: Using a biochemical assay for activation of the transcription factor Gli, a downstream component of the Hh pathway, we show here that Smo functions as the signaling component of the Shh receptor, and that this activity can be blocked by Ptc. The inhibition of Smo by Ptc can be relieved by the addition of Shh. Furthermore, oncogenic forms of Smo are insensitive to Ptc repression in this assay. Mapping of the Smo domains required for binding to Ptc and for signaling revealed that the Smo-Ptc interaction involves mainly the amino terminus of Smo, and that the third intracellular loop and the seventh transmembrane domain are required for signaling. CONCLUSIONS: These data demonstrate that Smo is the signaling component of a multicomponent Hh receptor complex and that Ptc is a ligand-regulated inhibitor of Smo. Different domains of Smo are involved in Ptc binding and activation of a Gli reporter construct. The latter requires the third intracellular loop and the seventh transmembrane domain of Smo, regions often involved in coupling to G proteins. No changes in the levels of cyclic AMP or calcium associated with such pathways could be detected following receptor activation, however.  (+info)

Alzheimer's disease: clues from flies and worms. (5/57141)

Presenilin mutations give rise to familial Alzheimer's disease and result in elevated production of amyloid beta peptide. Recent evidence that presenilins act in developmental signalling pathways may be the key to understanding how senile plaques, neurofibrillary tangles and apoptosis are all biochemically linked.  (+info)

Vac1p coordinates Rab and phosphatidylinositol 3-kinase signaling in Vps45p-dependent vesicle docking/fusion at the endosome. (6/57141)

The vacuolar protein sorting (VPS) pathway of Saccharomyces cerevisiae mediates transport of vacuolar protein precursors from the late Golgi to the lysosome-like vacuole. Sorting of some vacuolar proteins occurs via a prevacuolar endosomal compartment and mutations in a subset of VPS genes (the class D VPS genes) interfere with the Golgi-to-endosome transport step. Several of the encoded proteins, including Pep12p/Vps6p (an endosomal target (t) SNARE) and Vps45p (a Sec1p homologue), bind each other directly [1]. Another of these proteins, Vac1p/Pep7p/Vps19p, associates with Pep12p and binds phosphatidylinositol 3-phosphate (PI(3)P), the product of the Vps34 phosphatidylinositol 3-kinase (PI 3-kinase) [1] [2]. Here, we demonstrate that Vac1p genetically and physically interacts with the activated, GTP-bound form of Vps21p, a Rab GTPase that functions in Golgi-to-endosome transport, and with Vps45p. These results implicate Vac1p as an effector of Vps21p and as a novel Sec1p-family-binding protein. We suggest that Vac1p functions as a multivalent adaptor protein that ensures the high fidelity of vesicle docking and fusion by integrating both phosphoinositide (Vps34p) and GTPase (Vps21p) signals, which are essential for Pep12p- and Vps45p-dependent targeting of Golgi-derived vesicles to the prevacuolar endosome.  (+info)

Role of alphavbeta3 integrin in the activation of vascular endothelial growth factor receptor-2. (7/57141)

Interaction between integrin alphavbeta3 and extracellular matrix is crucial for endothelial cells sprouting from capillaries and for angiogenesis. Furthermore, integrin-mediated outside-in signals co-operate with growth factor receptors to promote cell proliferation and motility. To determine a potential regulation of angiogenic inducer receptors by the integrin system, we investigated the interaction between alphavbeta3 integrin and tyrosine kinase vascular endothelial growth factor receptor-2 (VEGFR-2) in human endothelial cells. We report that tyrosine-phosphorylated VEGFR-2 co-immunoprecipitated with beta3 integrin subunit, but not with beta1 or beta5, from cells stimulated with VEGF-A165. VEGFR-2 phosphorylation and mitogenicity induced by VEGF-A165 were enhanced in cells plated on the alphavbeta3 ligand, vitronectin, compared with cells plated on the alpha5beta1 ligand, fibronectin or the alpha2beta1 ligand, collagen. BV4 anti-beta3 integrin mAb, which does not interfere with endothelial cell adhesion to vitronectin, reduced (i) the tyrosine phosphorylation of VEGFR-2; (ii) the activation of downstream transductor phosphoinositide 3-OH kinase; and (iii) biological effects triggered by VEGF-A165. These results indicate a new role for alphavbeta3 integrin in the activation of an in vitro angiogenic program in endothelial cells. Besides being the most important survival system for nascent vessels by regulating cell adhesion to matrix, alphavbeta3 integrin participates in the full activation of VEGFR-2 triggered by VEGF-A, which is an important angiogenic inducer in tumors, inflammation and tissue regeneration.  (+info)

Cell growth inhibition by farnesyltransferase inhibitors is mediated by gain of geranylgeranylated RhoB. (8/57141)

Recent results have shown that the ability of farnesyltransferase inhibitors (FTIs) to inhibit malignant cell transformation and Ras prenylation can be separated. We proposed previously that farnesylated Rho proteins are important targets for alternation by FTIs, based on studies of RhoB (the FTI-Rho hypothesis). Cells treated with FTIs exhibit a loss of farnesylated RhoB but a gain of geranylgeranylated RhoB (RhoB-GG), which is associated with loss of growth-promoting activity. In this study, we tested whether the gain of RhoB-GG elicited by FTI treatment was sufficient to mediate FTI-induced cell growth inhibition. In support of this hypothesis, when expressed in Ras-transformed cells RhoB-GG induced phenotypic reversion, cell growth inhibition, and activation of the cell cycle kinase inhibitor p21WAF1. RhoB-GG did not affect the phenotype or growth of normal cells. These effects were similar to FTI treatment insofar as they were all induced in transformed cells but not in normal cells. RhoB-GG did not promote anoikis of Ras-transformed cells, implying that this response to FTIs involves loss-of-function effects. Our findings corroborate the FTI-Rho hypothesis and demonstrate that gain-of-function effects on Rho are part of the drug mechanism. Gain of RhoB-GG may explain how FTIs inhibit the growth of human tumor cells that lack Ras mutations.  (+info)

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The topology of the integral membrane protein MalF, which is required for maltose transport in Escherichia coli, has been analyzed using fusions of alkaline phosphatase (EC 3.1.3.1). The properties of such fusion strains support a MalF structure previously proposed on theoretical grounds. Several transmembrane segments within MalF can act as signal sequences in exporting alkaline phosphatase. Other transmembrane sequences, in conjunction with cytoplasmic domains, can stably anchor alkaline phosphatase in the cytoplasm. Our results suggest that features of the amino acid sequence (possibly the positively charged amino acids) of the cytoplasmic domains of membrane proteins are important in anchoring these domains in the cytoplasm. These studies in conjunction with our earlier results show that alkaline phosphatase fusions to membrane proteins can be an important aid in analyzing membrane topology and its determinants.. ...
The overexpression and purification of membrane proteins is a bottleneck in biotechnology and structural biology. E. coli remains the host of choice for membrane protein production. To date, most of the efforts have focused on genetically tuning of expression systems and shaping membrane composition to improve membrane protein production remained largely unexplored. In E. coli C41(DE3) strain, we deleted two transporters involved in fatty acid metabolism (OmpF and AcrB), which are also recalcitrant contaminants crystallizing even at low concentration. Engineered expression hosts presented an enhanced fitness and improved folding of target membrane proteins, which correlated with an altered membrane fluidity. We demonstrated the scope of this approach by overproducing several membrane proteins (4 different ABC transporters, YidC and SecYEG). In summary, E. coli membrane engineering unprecedentedly increases the quality and yield of membrane protein preparations. This strategy opens a new field for
Reliable prediction of structures could have a major impact on our understanding of membrane protein function. This is underscored by the fact that less than 1% of the structures in the Protein Data Bank are of integral membrane proteins despite these comprising over 20% of all genes in mammalian genomes. Membrane proteins are physiologically crucial given their function as a vital communication interface between the intracellular and extracellular environments, and between the cytosol and diverse membrane-bound organelles. Hence, many membrane proteins are pharmacologically important and are potential drug targets. While efforts in structural genomics have led to the elucidation of structures of numerous soluble proteins, determining the structure of membrane proteins remains challenging due to difficulties involved in their expression, purification and crystallization. Thus, any approach that provides insights into structures of membrane proteins will be very useful in explaining their ...
α-helical membrane proteins constitute 20-30% of all proteins in a cell and are involved in many essential cellular functions. The structure is only known for a few hundred of them, which makes structural models important. The most common structural model of a membrane protein is the topology which is a two-dimensional representation of the structure.. This thesis is focused on three different aspects of membrane protein structure: improving structural predictions of membrane proteins, improving the level of detail of structural models and the concept of dual topology.. It is possible to improve topology models of membrane proteins by including experimental information in computer predictions. This was first performed in Escherichia coli and, by using homology, it was possible to extend the results to 225 prokaryotic organisms. The improved models covered ~80% of the membrane proteins in E. coli and ~30% of other prokaryotic organisms.. However, the traditional topology concept is sometimes too ...
From the moment of cotranslational insertion into the lipid bilayer of the endoplasmic reticulum (ER), newly synthesized integral membrane proteins are subject to a complex series of sorting, trafficking, quality control, and quality maintenance systems. Many of these processes are intimately controlled by ubiquitination, a posttranslational modification that directs trafficking decisions related to both the biosynthetic delivery of proteins to the plasma membrane (PM) via the secretory pathway and the removal of proteins from the PM via the endocytic pathway. Ubiquitin modification of integral membrane proteins (or "cargoes") generally acts as a sorting signal, which is recognized, captured, and delivered to a specific cellular destination via specialized trafficking events. By affecting the quality, quantity, and localization of integral membrane proteins in the cell, defects in these processes contribute to human diseases, including cystic fibrosis, circulatory diseases, and various ...
p>The checksum is a form of redundancy check that is calculated from the sequence. It is useful for tracking sequence updates.,/p> ,p>It should be noted that while, in theory, two different sequences could have the same checksum value, the likelihood that this would happen is extremely low.,/p> ,p>However UniProtKB may contain entries with identical sequences in case of multiple genes (paralogs).,/p> ,p>The checksum is computed as the sequence 64-bit Cyclic Redundancy Check value (CRC64) using the generator polynomial: x,sup>64,/sup> + x,sup>4,/sup> + x,sup>3,/sup> + x + 1. The algorithm is described in the ISO 3309 standard. ,/p> ,p class="publication">Press W.H., Flannery B.P., Teukolsky S.A. and Vetterling W.T.,br /> ,strong>Cyclic redundancy and other checksums,/strong>,br /> ,a href="http://www.nrbook.com/b/bookcpdf.php">Numerical recipes in C 2nd ed., pp896-902, Cambridge University Press (1993),/a>),/p> Checksum:i ...
Proteins of the p24 family form a rather unique family of abundant, small (20-24 kDa) type I trans-membrane proteins in the early biosynthetic pathway. They can be sub-divided by sequence homology into 4 sub-families (p23 or delta, p24 or beta, p25 or alpha, and p26 or gamma) (Dominguez et al., 1998; Emery et al., 1999). Mammalian cells contain at least one member of each p23, p24 and p25 subfamily, and three members of the p26 sub-family (Emery et al., 1999). All seem to cycle in the early secretory pathway (Blum et al., 1999; Fullekrug et al., 1999; Rojo et al., 2000), and to localize primarily to the cis-Golgi network (CGN) or the cis side of the Golgi complex (Emery et al., 2000; Fullekrug et al., 1999; Rojo et al., 1997; Stamnes et al., 1995), except p25 (GP25L) which is also abundant in the endoplasmic reticulum (ER) (Dominguez et al., 1998; Wada et al., 1991). They share a predicted exoplasmic coiled-coil domain and a small (12-18 amino acids) cytoplasmically oriented C terminus that ...
Creative Biostructure, featured as a leader in the structural biology field, now provides a comprehensive list of custom membrane protein services from gene to structure with an emphasis on protein purification, crystallization, structure determination and analysis.. Although membrane proteins play an important role in all organisms, their purification has historically, and continues to be, a huge challenge for protein scientists. In 2008, 150 unique structures of membrane proteins were available, and by 2019 only 50 human membrane proteins had their structures elucidated. For the important roles they play in cell functions, membrane proteins are now considered to be perfect drug targets. Investigating membrane protein structure and function can provide valuable information for drug characterization and optimization, however, such proteins are inherently difficult to purify and characterize. Even when expressed at high levels, the purification can still be challenging.. Owing to years of devoted ...
My research is on membrane protein structure, dynamics, and function with a focus on membrane proteins involved in bacterial pathogenesis. I teach CHEM4411 and CHEM4421, the Biological Chemistry Laboratory courses at UVa. With my colleagues, Carol Price and Cameron Mura, I have developed a year long inquiry- and research-based biochemistry laboratory. We have created BioLEd to share and enable faculty to more easily develop their undergraduate biochemistry laboratories and research.. ...
The ERM family members, ezrin, radixin, and moesin, localizing just beneath the plasma membranes, are thought to be involved in the actin filament/plasma membrane association. To identify the integral membrane protein directly associated with ERM family members, we performed immunoprecipitation studies using antimoesin mAb and cultured baby hamster kidney (BHK) cells metabolically labeled with [35S]methionine or surface-labeled with biotin. The results indicated that moesin is directly associated with a 140-kD integral membrane protein. Using BHK cells as antigens, we obtained a mAb that recognized the 140-kD membrane protein. We next cloned a cDNA encoding the 140-kD membrane protein and identified it as CD44, a broadly distributed cell surface glycoprotein. Immunoprecipitation with various anti-CD44 mAbs showed that ezrin and radixin, as well as moesin, are associated with CD44, not only in BHK cells, but also in mouse L fibroblasts. Furthermore, immunofluorescence microscopy revealed that in ...
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peripheral membrane protein (Science: protein) membrane proteins that are bound to the surface of the membrane and not integrated into the hydrophobic region. Usually soluble and were originally thought to bind to integral proteins by ionic and other weak forces (and could therefore be removed by high ionic strength, for example). However, it is now clear that some peripheral membrane proteins are covalently linked to molecules that are part of the membrane bilayer (see acylated proteins and glypiation) and that there are others that fit the original definition but are perhps more appropriately considered proteins of the cytoskeleton (e.g. Band 4.1 and spectrin) or extracellular matrix (e.g. Fibronectin). ...
The module will cover the structure and function of biological membranes. There will be a general introduction to membrane structure and a discussion of the biosynthesis of membrane proteins. The insertion of membrane proteins into bio-membranes is introduced by matching physic-chemical properties and investigated for spontaneous membrane protein insertion. Protein complexes involved in membrane protein insertion and in transport across the membrane will be introduced. The electron transport chain and its relation to energy transduction will be covered together with an introduction to Mitchells chemi-osmotic hypothesis. The structure and function of specific membrane proteins involved in electron transport, proton translocation and phosphorylation in mitochondria and photosynthesis will be described and discussed in terms of our present understanding of how oxidation reactions or light energy are coupled to the synthesis of ATP. The role of multi-domain cell surface proteins in cell recognition ...
Membrane proteins are of great biomedical importance. They account for ~25% of all genes and are involved in diseases ranging from diabetes to cancer. Membrane proteins play a key role in the biology of infection by pathogens, including both bacteria and viruses. They also play an important role in signalling within and between cells. It is therefore not surprising that membrane proteins are major targets for a wide range of drugs and other therapeutic agents. Recently, the number of known structures of membrane proteins has started to increase. Large scale computer simulations allow researchers to study the movements of these proteins in their native membrane environments. 
A: The fluid mosaic model of membrane structure. The membrane consists of a phospholipid double layer with proteins inserted in it (integral proteins) or bound to the cytoplasmic surface (peripheral proteins). Integral membrane proteins are firmly embedded in the lipid layers. Some of these proteins completely span the bilayer and are called transmembrane proteins, whereas others are embedded in either the outer or inner leaflet of the lipid bilayer. The dotted line in the integral membrane protein is the region where hydrophobic amino acids interact with the hydrophobic portions of the membrane. Many of the proteins and lipids have externally exposed oligosaccharide chains. B: Membrane cleavage occurs when a cell is frozen and fractured (cryofracture). Most of the membrane particles (1) are proteins or aggregates of proteins that remain attached to the half of the membrane adjacent to the cytoplasm (P, or protoplasmic, face of the membrane). Fewer particles are found attached to the outer half ...
This project seeks to determine the mechanisms, structures, and structure change of integral transmembrane proteins that govern critical transmembrane processes, at the level that can lead to improved therapeutics for human disease. The premise is that alterations in molecular structures are necessary for the function of transmembrane transporters and gated channels, and are coordinated by regulatory functions. The hypothesis is that understanding the linkage between structure change and function provides a roadmap for therapeutic intervention by organic compounds or Fab fragments generated to stabilize conformational states. A major innovation is the technology and ability to determine atomic structures of membrane proteins and eukaryotic, or human membrane proteins at a resolution sufficient to instruct in the development of therapeutic development of compounds. Principal technologies include X-ray diffraction, electron cryomicroscopy, transport assays, electrophysiology. Three aims focus on ...
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Membrane proteins fulfil a number of tasks in cells, including signalling, cell-cell interaction, and the transportation of molecules. The prominence of these tasks makes membrane proteins an important target for clinical drugs. Because of the decreasing price of sequencing, the number of sequences known is increasing at such a rate that manual annotations cannot compete. Here, topology prediction is a way to provide additional information. It predicts the location and number of transmembrane helices in the protein and the orientation inside the membrane. An important factor to detect transmembrane helices is their hydrophobicity, which can be calculated using dedicated scales. In the first paper, we studied the difference between several hydrophobicity scales and evaluated their performance. We showed that while they appear to be similar, their performance for topology prediction differs significantly. The better performing scales appear to measure the probability of amino acids to be within a ...
Integral membrane proteins (SCAMPs), tetraspan vesicle membrane proteins) that act as carriers, recycling proteins to the cell surface. At least three members of the family have been identified in humans: SCAMP1 (338 aa), SCAMP2 (329 aa), and SCAMP3 (347 aa). ...
Proteins and channels , Hydrophobicity , Self-assembly ,,. Hydrophobicity literally means "fear of water". The opposite of this is hydrophilicity which means "love of water". These two terms denote the properties of molecules or parts of molecules to bond with water (hydrophilicity) or reject water (hydrophobicity). This effect is seen when one puts a drop of oil on water. The oil (hydrophobic) remains on the surface and sticks together in stead of mixing with the water (hydrophilic). In cells these properties are essential. Most of the cell is hydrophilic but there are hydrophobic borders (membranes) which compartmentalize the cell into different spaces and hereby separate reactions. Of course there must be some sort of interaction between compartments and this is facilitated by membrane proteins (look here to read up on membrane proteins).. These membranes are formed with molecules with hydrophobic properties, such as phospholipids, cholesterol and membrane proteins. The phospholipids and ...
Junctional complexes between the plasma membrane (PM) and endoplasmic/sarcoplasmic reticulum (ER/SR) are a common feature of all excitable cell types and mediate cross talk between cell surface and intracellular ion channels. Junctophilins (JPs) are important components of the junctional complexes. JPs are composed of a carboxy-terminal hydrophobic segment spanning the ER/SR membrane and a remaining cytoplasmic domain that shows specific affinity for the PM. Four JPs have been identified as tissue-specific subtypes derived from different genes: JPH1 is expressed in skeletal muscle, JPH2 is detected throughout all muscle cell types, and JPH3 and JPH4 are predominantly expressed in the brain. In the CNS, both JPH3 and JPH4 are expressed throughout neural sites and contribute to the subsurface cistern formation in neurons. Mice lacking both JPH3 and JPH4 subtypes exhibit serious symptoms such as impaired learning and memory and are accompanied by abnormal nervous functions. A repeat expansion in ...
Voltage gated potassium channels are transmembrane protein complexes that form a pore specifically allowing the passage of potassium ions. One method to determine the structure of these and other membrane proteins is electron crystallography. For this, purified membrane proteins are mixed with lipids and induced to form two-dimensional crystals. These flat crystal sheets are then imaged by cryo-EM and analysed. There is no potential gradient across them as the protein is surrounded by the same buffer. The gradient required for voltage gated channel proteins to function can be created if they are embedded in a spherical lipid bilayer that encloses liquid, i.e., if they are embedded in the membrane of a liposome. The buffer conditions inside and outside the liposomes dictate whether they are in an open or a closed conformation ...
Membrane proteins are critical components of all cells, controlling, e.g., signaling, nutrient exchange, and energy production, and are the target of over half of all drugs currently in production. At an early stage of their synthesis, nearly all membrane proteins are directed to a protein-conducting channel, the SecY/Sec61 complex, which permits access to the membrane via its lateral gate.
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Integral membrane proteins are found within the plasma membrane and span the whole length across. The inside of the membrane is very hydrophobic due to the long carbon chains. Extensive hydrophobic interactions between the protein side chain and the lipid tails will help anchor the protein in the membrane.. ...
Presented in this section is an adherent culture of Swiss mouse embryo fibroblasts that was immunofluorescently labeled with Rhodamine Red conjugated to antibodies directed against peroxisomal membrane protein 70 (PMP 70), an abundant and integral membrane component of peroxisomes.
Presented in the digital image in this section is a culture of Swiss mouse embryo fibroblasts that was immunofluorescently labeled with Rhodamine Red conjugated to antibodies directed against peroxisomal membrane protein 70 (PMP 70), an abundant and integral membrane component of peroxisomes.
JC just returned from two back-to-back meetings in Snowmass, CO. He presented work on small-helix partitioning in membranes at the first meeting on Free Energy Methods and structures of BamA and a new complex between SecY and a nascent chain at the second meeting on Membrane Proteins. Not all the time was spent in front of a screen though, as the picture to the right clearly shows!. ...
The Valiyaveetil lab studies potassium channels, which are integral membrane proteins that catalyze the selective conduction of K+ ions across biological membranes. While a great deal of research has been focused on these channels, fundamental questions regarding the mechanism of ionic selectivity and gating remain. Valiyaveetils team has developed a unique combination of methods to address these questions. Their methods include the use of chemical synthesis to introduce precise chemical changes in the channels, x-ray crystallography to determine the structural effects and electrophysiology to determine the functional effects of these changes. Using this multidisciplinary approach they hope to explain the mechanism of ion selectivity and channel gating.. ...
Membrane proteins play an essential role in controlling the movement of material and information in and out of the cell, in determining the flow and use of energy, as well as in triggering the initiation of numerous signaling pathways. To fulfill these roles, conformational and interaction dynamics exert a dominant influence on their functional behavior, for it is the interplay between structure and dynamics what ultimately defines their function.. The Membrane Protein Structural Dynamics Consortium (MPSDC) has been designed as a highly interactive, tightly integrated and multidisciplinary effort focused on elucidating the relationship between structure, dynamics and function in a variety of membrane proteins. This website serves as a gateway both to the Consortiums activities and resources, and to the scientific field at large. Read the directors statement ». ...
Separation of integral membrane proteins by 2-DE. The integral proteins were separated using 18-cm IPG strips covering pH ranges 3-10 (nonlinear), and 4-7 f
Coll, J M.; Luborsky, S W.; and Mora, P T., "Metabolically labeled cell membrane proteins in spontaneously and in sv40 virus transformed mouse fibroblasts." (1977). Subject Strain Bibliography 1977. 1406 ...
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The rate at which X-ray structures of membrane proteins are solved is on a par with that of soluble proteins in the late 1970s. There are still many obstacles facing the membrane protein structural community. Recently, there have been several technical achievements in the field that have started to dramatically accelerate structural studies. Here, we summarize these so-called tricks-of-the-trade and include case studies of several mammalian transporters.
Build: Wed Jun 21 18:33:50 EDT 2017 (commit: 4a3b2dc). National Center for Advancing Translational Sciences (NCATS), 6701 Democracy Boulevard, Bethesda MD 20892-4874 • 301-435-0888. ...
The research in our group focuses on the structural biochemistry and biophysics of membrane proteins. Membrane proteins perform most of the important processes in all living cells. For example, respiration, photosynthesis, cell communication, cell import/export, cell growth and recognition are catalyzed and regulated by membrane proteins. These proteins do not act in an isolated way; they rather perform communication within the cell by binding and releasing of cofactors and soluble signal-transducing proteins. Membrane proteins are also key player in infectious diseases as they mediate entry of viral and bacterial pathogens into the host cell and also play an important role in the cell defense against the pathogens.. The main step for the elucidation of the complex in whole living cells is the understanding of the structure, dynamics and function of the membrane proteins that play the key role in these processes. Our research field is of a very interdisciplinary nature and includes biochemical ...
Membrane proteins are essential for signal transduction and the transfer of proteins and small molecules across the biological membrane. Our research is focused on structural biology of integral membrane proteins. We are particularly interested in Ca2+ transport and signaling, vitamin transport, and intramembrane proteases. In addition, we develop methods for time-resolved structural studies and apply novel membrane mimics to biologically interesting systems ...
Gunnar von Heijne is being recognized for his profound contributions in creating important theoretical and experimental tools towards advancing our understanding of both principles and mechanisms of membrane protein biosynthesis. Funded by Anatrace, Inc., this award recognizes an outstanding investigator who has made a significant contribution to the field of membrane protein research. ...
A few more questions, are the IPed proteins cytosolic or membrane bound? Are you using total cell lysate? If yes, when you make the lysate, which speed did you spin down the lysate (to get rid of the debris, un broken cells...) before adding in Ab? The reason I ask is that if the IPed proteins are membrane proteins (still bound with membrane even after lysis) and you prepare the lysate at speed less than 3Krpm, then when you wash the beads, the free membrane will also come down together with beads. Then when you run the gel, you will got these free membrane proteins in all samples.. ...
CD38 (AT13/5), 0.5 ml. CD38 (T10) is a single chain 42 to 46 kDa type II integral transmembrane glycoprotein with a short N terminal cytoplasmic tail.
CBAP (Common receptor Beta chain Associating Protein) is a putative transmembrane protein which associates preferentially with unliganded GM-CSFR beta chain. It functions as a pro-apoptotic protein and is widely expressed in various cell types ...
Bacterial integral membrane proteins play many important roles, including sensing changes in the environment, transporting molecules into and out of the cell, and in the case of commensal or pathogenic bacteria, interacting with the host organism
Membrane proteins are medically important as they represent more than half of all present day drug targets. Visit Eurisotop to learn more.
Yes. SNAP- and CLIP-tags can be fused to either the N- or C-terminus of a protein of interest. However, to label surface proteins on the outside of cells using SNAP-, CLIP- the tag must be cloned so that it is oriented to the extracellular surface of the plasma membrane. In this orientation, the tag is accessible to its fluorophore conjugated substrate ...
Free practice questions for GRE Subject Test: Biology - Understanding Membrane Proteins. Includes full solutions and score reporting.
Putative adhesion receptor, that could be involved in cell-cell or cell-matrix interactions required for normal cell differentiation and migration.
Scientists have described an improved, cost-efficient method to isolate membrane proteins, a class of proteins that are the targets of more than 60 percent of approved therapeutic drugs.
Subcellular Localization: Membrane; Single-pass type I membrane protein (By similarity). Cytoplasm. Cytoplasm, perinuclear region. Note=Predominantly perinuclear ...
Itm2b - Itm2b (untagged) - Mouse integral membrane protein 2B (Itm2b), (10ug) available for purchase from OriGene - Your Gene Company.
CLIC1 is an intracellular membrane protein that has an unusual property distinct from typical membrane proteins. It is able to exist in both a soluble and membrane-bound form in cells. The membrane-insertion mechanism ...
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DESCRIPTION provided by applicant The increasing output of new integral membrane protein IMP structures is partially due to the availability of an increasing number of chemical variables such as ... ...
Cellular processesCellular processesSporulation and germinationsporulation integral membrane protein YlbJ (TIGR02871; HMM-score: 28.4) ...
The coding guidelines state that conditions that are integral to the disease process should not be assigned as additional codes. Does the
Background: Although suicide is a leading cause of death in the United States and represents a significant public health threat, little is known about the neurobiological or molecular factors that contribute to its pathophysiology. A number of studies now indicate that lithium has considerable efficacy in the prevention of suicide in patients with affective disorders, and accumulating evidence indicates that protein kinase C (PKC) and its substrates, in particular the myristoylated alanine-rich C kinase substrate (MARCKS), are primary targets of chronic lithium treatment. We therefore hypothesized that a dysregulation in MARCKS expression in key brain regions could contribute to the pathophysiology associated with suicide. To address this, we examined MARCKS, as well as the closely related MARCKS-related protein (MRP), mRNA expression in the hippocampus and dorsolateral prefrontal cortex of suicide victims and normal controls. Method: MARCKS and MRP mRNA expression was assessed by quantitative ...
TY - JOUR. T1 - Endothelial dysfunction in Type 2 diabetes correlates with deregulated expression of the tail-anchored membrane protein SLMAP. AU - Ding, Hong. AU - Howarth, Andrew G.. AU - Pannirselvam, Malarvannan. AU - Anderson, Todd J.. AU - Severson, David L.. AU - Wiehler, William B.. AU - Triggle, Christopher. AU - Tuana, Balwant S.. PY - 2005/7. Y1 - 2005/7. N2 - The Type 2 diabetic db/db mouse experiences vascular dysfunction typified by changes in the contraction and relaxation profiles of small mesenteric arteries (SMAs). Contractions of SMAs from the db/db mouse to the α1-adrenoceptor agonist phenylephrine (PE) were significantly enhanced, and acetylcholine (ACh)-induced relaxations were significantly depressed. Drug treatment of db/db mice with a nonthiazolidinedione peroxisome prolifetor-activated receptor-γ agonist and insulin sensitizing agent 2-[2-(4-phenoxy-2-propylphenoxy)ethyl]indole-5-acetic acid (COOH) completely prevented the changes in endothelium-dependent relaxation, ...
Cell fusion occurs throughout development, from fertilization to organogenesis. The molecular mechanisms driving plasma membrane fusion in these processes remain unknown. While yeast mating offers an excellent model system in which to study cell fusion, all genes previously shown to regulate the process act at or before cell wall breakdown; i.e., well before the two plasma membranes have come in contact. Using a new strategy in which genomic data is used to predict which genes may possess a given function, we identified PRM1, a gene that is selectively expressed during mating and that encodes a multispanning transmembrane protein. Prm1p localizes to sites of cell-cell contact where fusion occurs. In matings between Deltaprm1 mutants, a large fraction of cells initiate zygote formation and degrade the cell wall separating mating partners but then fail to fuse. Electron microscopic analysis reveals that the two plasma membranes in these mating pairs are tightly apposed, remaining separated only by ...
When the pH of BSK-H was adjusted to 6.0, 7.0, and 8.0, we observed at least 37 alterations in the membrane protein profile, suggesting that pH may play a regulatory role in the expression of many of these membrane proteins. Initially, six of these changes were seen by immunoblotting with hyperimmune serum or serum derived from a tick-acquired infection, suggesting that the immunogens observed at pHs 6.0 and 7.0 (Fig. 1) are expressed during infection. The hyperimmune serum also reacted with a 42-kDa membrane protein that increased in amount as the pH of the medium was increased from 6.0 to 8.0 (Fig. 1). In addition, the tick bite immune serum recognized a 48- and a 46-kDa protein that went undetected when probed with hyperimmune serum. This also suggests that there may be numerous membrane proteins expressed at pHs 6.0 and 7.0 which may be differentially expressed during the infectious cycle and not recognized by the hyperimmune serum. These alterations in membrane proteins as the pH of the ...
The contribution of linked background genes to the phenotype of mutant mice has been documented (7) as have the significant behavioral differences between inbred mouse strains (6). The 129Sv strain used in the generation of our mutant mice exhibit IP-MF hypoplasia (2) and impaired spatial learning in the Morris water maze (6). In our study, comparison of 129B6(N3) mice, which posses on average 12.5% residual 129Sv-linked genes; 129B6(N9) mice, which posses on average 0.2% residual 129Sv-linked genes; and inbred C57BL/6J mice, which possess no 129Sv-linked genes, revealed the significant contribution of 129Sv background genes to the phenotype. First, mutant 129B6(N3) mice, but not mutant 129B6(N9) mice, exhibited a significant elevation in hippocampal PKCɛ expression relative to wild-type controls. Second, wild-type 129B6(N3) mice exhibited significant IP-MF hypoplasia relative to both inbred C57BL/6J and wild-type 129B6(N9) mice, which is consistent with the 129Sv phenotype (2), and likely ...
File scanned at 300 ppi (Monochrome, 24-bit Color) using Capture Perfect 3.0.82 on a Canon DR-9080C in PDF format. CVista PdfCompressor 4.0 was used for pdf compression and textual OCR ...
TY - JOUR. T1 - Toward structure determination using membrane-protein nanocrystals and microcrystals. AU - Hunter, Mark S.. AU - Fromme, Petra. PY - 2011/12/1. Y1 - 2011/12/1. N2 - Membrane proteins are very important for all living cells, being involved in respiration, photosynthesis, cellular uptake and signal transduction, amongst other vital functions. However, less than 300 unique membrane protein structures have been determined to date, often due to difficulties associated with the growth of sufficiently large and well-ordered crystals. This work has been focused on showing the first proof of concept for using membrane protein nanocrystals and microcrystals for high-resolution structure determination. Upon determining that crystals of the membrane protein Photosystem I, which is the largest and most complex membrane protein crystallized to date, exist with only 100. unit cells with sizes of less than 200. nm on an edge, work was done to develop a technique that could exploit the growth of ...
Vadim Kotov, Kim Bartels, Katharina Veith, Inokentijs Josts, Udaya K. Tiruttani Subhramanyam, Christian Günther, Jörg Labahn, Thomas C. Marlovits, Isabel Moraes, Henning Tidow, Christian Löw & Maria M. Garcia-Alai Scientific Reports 2019 vol: 9 Article number: 10379 doi: 10.1038/s41598-019-46686-8. Abstract. Protein stability in detergent or membrane-like environments is the bottleneck for structural studies on integral membrane proteins (IMP). Irrespective of the method to study the structure of an IMP, detergent solubilization from the membrane is usually the first step in the workflow. Here, we establish a simple, high-throughput screening method to identify optimal detergent conditions for membrane protein stabilization. We apply differential scanning fluorimetry in combination with scattering upon thermal denaturation to study the unfolding of integral membrane proteins. Nine different prokaryotic and eukaryotic membrane proteins were used as test cases to benchmark our detergent ...
The manner in which a membrane protein is anchored to the lipid bilayer may have a profound influence on its function. Most cell surface membrane proteins are anchored by a membrane-spanning segment(s) of the polypeptide chain, but another type of anchor has been described for several proteins: a phosphatidyl inositol glycan moiety, attached to the protein C terminus. This type of linkage has been identified on membrane proteins involved in adhesion and transmembrane signalling and could be important in the execution of these functions. We report here that an immunologically important adhesion glycoprotein, lymphocyte function-associated antigen 3 (LFA-3), can be anchored to the membrane by both types of mechanism. These two distinct cell-surface forms of LFA-3 are derived from different biosynthetic precursors. The existence of a phosphatidyl-inositol-linked and a transmembrane anchored form of LFA-3 has important implications for adhesion and transmembrane signalling by LFA-3.
TY - JOUR. T1 - Combining in Vitro Folding with Cell Free Protein Synthesis for Membrane Protein Expression. AU - Focke, Paul J.. AU - Hein, Christopher. AU - Hoffmann, Beate. AU - Matulef, Kimberly. AU - Bernhard, Frank. AU - Dötsch, Volker. AU - Valiyaveetil, Francis. PY - 2016/8/2. Y1 - 2016/8/2. N2 - Cell free protein synthesis (CFPS) has emerged as a promising methodology for protein expression. While polypeptide production is very reliable and efficient using CFPS, the correct cotranslational folding of membrane proteins during CFPS is still a challenge. In this contribution, we describe a two-step protocol in which the integral membrane protein is initially expressed by CFPS as a precipitate followed by an in vitro folding procedure using lipid vesicles for converting the protein precipitate to the correctly folded protein. We demonstrate the feasibility of using this approach for the K+ channels KcsA and MVP and the amino acid transporter LeuT. We determine the crystal structure of the ...
The biogenesis of most membrane proteins is governed by specific interactions between the newly synthetized nascent polypeptide chain and the evolutionary conserved and essential insertases and translocases (1-3). Insertases and translocases recognize their substrate and lower the free-energy barrier for inserting and folding the polypeptide into cellular membranes (3, 4). This insertion and folding can occur cotranslationally as the polypeptide exits the ribosome or posttranslationally after the polypeptide has been released by the ribosome. The bacterial translocase SecYEG has a eukaryotic homolog, Sec61, in the endoplasmatic reticulum (1), whereas the bacterial insertase YidC has Oxa1 and Oxa2 homologs in mitochondria, Get1 in endoplasmatic reticulum, and Alb3 in chloroplasts (5-7). In Gram-negative bacteria, SecYEG folds α-helical membrane proteins into the inner membrane and translocates precursors of soluble periplasmic and β-barrel outer membrane proteins to the periplasm (1, 8). ...
The function of any given biological membrane is determined largely by the specific set of integral membrane proteins embedded in it, and the peripheral membrane proteins attached to the membrane surface. The activity of these proteins, in turn, can be modulated by the phospholipid composition of the membrane. The reconstitution of membrane proteins into a model membrane allows investigation of individual features and activities of a given cell membrane component. However, the activity of membrane proteins is often difficult to sustain following reconstitution, since the composition of the model phospholipid bilayer differs from that of the native cell membrane. This review will discuss the reconstitution of membrane protein activities in four different types of model membrane - monolayers, supported lipid bilayers, liposomes and nanodiscs, comparing their advantages in membrane protein reconstitution. Variation in the surrounding model environments for these four different types of membrane layer can
The function of any given biological membrane is determined largely by the specific set of integral membrane proteins embedded in it, and the peripheral membrane proteins attached to the membrane surface. The activity of these proteins, in turn, can be modulated by the phospholipid composition of the membrane. The reconstitution of membrane proteins into a model membrane allows investigation of individual features and activities of a given cell membrane component. However, the activity of membrane proteins is often difficult to sustain following reconstitution, since the composition of the model phospholipid bilayer differs from that of the native cell membrane. This review will discuss the reconstitution of membrane protein activities in four different types of model membrane - monolayers, supported lipid bilayers, liposomes and nanodiscs, comparing their advantages in membrane protein reconstitution. Variation in the surrounding model environments for these four different types of membrane layer can
Objectives: The composition of nuclear membrane proteins (NMP) of fibroblasts derived from the periodontium is unknown. Identification of NMP is complicated since extraction of membrane proteins can be difficult due to the lipophilic nature of these molecules. The purpose of this study was to compare the quantity of unique identifiable membrane proteins using a single enzymatic wash preparation versus a two wash preparation for digestion and denaturation in proteomic analysis. Methods: GF used were obtained from 2 human biopsies derived from non-inflamed tissue in the retromolar pad area. Cells were cultured and propogated in Eagles minimal essential medium supplemented with 10% fetal bovine serum. GF were harvested when confluent in the 4th cell culture passage. NMP were isolated by differential centrifugation. 15 μg of protein from each sample was digested with trypsin or trypsin followed by a urea wash, followed by iTRAQ™ mass labeling for peptide qualitative and quantitative ...
We proposed to apply a chemical cross-linking, mass spectrometry and modeling method called MS3D to the structure determination of the rhodopsin-transducin membrane protein complex (RTC). Herein we describe experimental progress made to adapt the MS3D approach for characterizing membrane protein systems, and computational progress in experimental design, data analysis and protein structure modeling. Over the past three years, we have developed tailored experimental methods for all steps in the MS3D method for rhodopsin, including protein purification, a functional assay, cross-linking, proteolysis and mass spectrometry. In support of the experimental effort. we have out a data analysis pipeline in place that automatically selects the monoisotopic peaks in a mass spectrometric spectrum, assigns them and stores the results in a database. Theoretical calculations using 24 experimentally-derived distance constraints have resulted in a backbone-level model of the activated form of rhodopsin, which is a
Junctophilin 2, also known as JPH2, is a protein which in humans is encoded by the JPH2 gene. Alternative splicing has been observed at this locus and two variants encoding distinct isoforms are described. Junctional complexes between the plasma membrane and endoplasmic/sarcoplasmic reticulum are a common feature of all excitable cell types and mediate cross talk between cell surface and intracellular ion channels. The protein encoded by this gene is a component of junctional complexes and is composed of a C-terminal hydrophobic segment spanning the endoplasmic/sarcoplasmic reticulum membrane and a remaining cytoplasmic membrane occupation and recognition nexus (MORN) domain that shows specific affinity for the plasma membrane. JPH2 is a member of the junctophilin gene family (the other members of the family are JPH1, JPH3, and JPH4) and is the predominant isoform in cardiac tissue, but is also expressed with JPH1 in skeletal muscle. The JPH2 protein product plays a critical role in maintaining ...
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Tetraspanins are family of small membrane proteins and they are involved in multitude of biological process. Structurally theyare characterized by having four transmembrane domains, short inner and outer loops, one large extra cellular loop containsCCG motif and N and C terminal. Iconic features of these proteins are formation of Tetraspanin Enriched Micro domains(TEMs) by interacting among themselves and with other transmembrane and cytosolic proteins. These domains provide asignaling platform for many important cellular functions such as immune response induction, fertilization, viral infection,maintenance of skin integrity and malignant process. Tetraspanin CD151 is frequently over expressed on cancer cells and isfunctionally linked to cancer metastasis. CD151 forms direct and stable and interaction with integrin molecules and regulatesthe cellular functions. Increasing evidence emerging from in vitro, in vivo and clinical analyses associates that CD151partnership with integrins ?6?1 and ...
The primary objective of our work was to find a practical solution to the limitations of GPCR expression imposed by heterologous systems. Although relatively large amounts of membrane proteins can be potentially produced in cellular systems, usually a small proportion becomes associated to the membrane [22]. Particularly, GPCRs are confronted to a complex array of trafficking signals, post-translational modifications, and transport systems before reaching the final destination, the plasma membrane. In addition, differences in the lipid bilayer composition and maximal tolerated membrane protein loads can additionally affect the correct insertion, folding, and yield of recombinant GPCRs.. In order to overcome these difficulties, we developed a cell-free expression system supplemented with planar membranes [15]. Although, the approach excels in expressing soluble membrane protein products, it fails to produce functional GPCRs. We favor the absence of a functional translocon machinery embedded in ...
Palmitoylation, the attachment of palmitate and other fatty acids on to cysteine residues, is a common post-translational modification of both integral and peripheral membrane proteins. Dynamic palmitoylation controls the intracellular distribution of peripheral membrane proteins by regulating membrane-cytosol exchange and/or by modifying the flux of the proteins through vesicular transport systems.. ...
The ease with which a cell membrane can bend and deform is important for a wide range of biological functions. Peripheral proteins that induce curvature in membranes (e.g. BAR domains) have been studied for a number of years. Little is known, however, about the effect of integral membrane proteins on the sti Surfactants & lipids Biological soft matter
Recognition by scavenger receptor cysteine-rich domains on membrane proteins regulates innate and adaptive immune responses. Two receptors expressed primarily on T cells, CD5 and CD6, are linked genetically and are structurally similar, both containing three scavenger receptor cysteine-rich domains in their extracellular regions. A specific cell surface interaction for CD5 has been difficult to define at the molecular level because of the susceptibility of CD5 protein to denaturation. By using soluble CD5 purified at neutral pH to preserve biological activity, we show that CD5 mediates species-specific homophilic interactions. CD5 domain 1 only is involved in the interaction. CD5 mAbs that have functional effects in humans, rats, and mice block homophilic binding. Ag-specific responses by mouse T cells in vitro were increased when engagement of human CD5 domain 1 was inhibited by mutation or by IgG or Fab fragment from a CD5 mAb. This showed that homophilic binding results in productive ...
Love J, Mancia F, Shapiro L, Punta M, Rost B, Girvin M, Wang D-N, Zhou M, Hunt JF, Szyperski T, et al. The New York Consortium on Membrane Protein Structure (NYCOMPS): a high-throughput platform for structural genomics of integral membrane proteins. J Struct Funct Genomics. 2010 ;11(3):191-9. ...
Love J, Mancia F, Shapiro L, Punta M, Rost B, Girvin M, Wang D-N, Zhou M, Hunt JF, Szyperski T, et al. The New York Consortium on Membrane Protein Structure (NYCOMPS): a high-throughput platform for structural genomics of integral membrane proteins. J Struct Funct Genomics. 2010 ;11(3):191-9. ...
... s are an integral part of molecular biology research. These proteins interact with biological membranes and are the target of over 50% of all modern medicinal drugs. Membrane proteins perform a variety of functi...(Expand Details)ons that are crucial to the survival of organisms such as relaying signals, transport, and cell adhesion. Additionally, approximately 20 - 30 % of genes within a genome encode membrane proteins.. At BioChain, weve prepared membrane proteins from a large variety of documented quality tissues that are ready-to-use for genetic testing and analysis. Our tissue membranes are prepared from whole tissue homogenates and are of high-quality. Distinction of quality is ensured by consistent patterns on SDS-PAGE analysis, as well as by storage in protease inhibitor cocktail buffer.. Features. ...
Interferon-inducible transmembrane protein IFITM3 was recognized to restrict the access of a wide spectrum of viruses to the cytosol of the sponsor. section in the N-terminal hydrophobic region. Solution NMR studies of the same sample verified the secondary structure distribution and shown two rigid areas interacting with the micellar surface. The producing membrane topology of IFITM3 supports the mechanism of an enhanced restricted membrane hemi-fusion. A small membrane protein family called the interferon-inducible transmembrane (IFITM) was recently discovered and is under active exploration. This family restricts an array of pathogenic viral attacks with different inhibitory extents for different infections1 2 3 For instance IFITMs inhibit the mobile entrance and replication of individual immunodeficiency trojan (HIV) the influenza A trojan vesicular stomatitis trojan the rabies the Western world Nile trojan the dengue trojan the SARS corona trojan the Marburg trojan the Ebola trojan the ...
Membrane protein topology predictions can be markedly improved by the inclusion of even very limited experimental information. We have recently introduced an approach for the production of reliable topology models based on a combination of experimental determination of the location (cytoplasmic or p …
Sarah Perry - Models to Medicine Center - Research areas include microfluidics, soluble and membrane protein structure determination, protein crystallography, protein structural dynamics, biomimetic microenvironments, and tailoring protein activity and stability. - M2M IALS - UMass Amherst
This issue with detergents led scientists to believe that membrane proteins were delicate relative to other proteins. When in the cell membrance, however, integral proteins are stabilized by multiple factors including the shielding of the hydrophobic portions of the protein and lateral pressure exerted by the lipid bilayer. These factors are not present in the detergent-solubilized state. Also, the introduction of artifacts from the detergent may appear. That causes the membrane proteins to be more susceptible to their loss of native structure which also results in the deactivation of the protein. The effectiveness of the detergents used is based on the particular protein and the detergent used. A poor detergentwill serve as a poor substitute for the lipid bilayer, causing the protein to degrade. This all interferes with the studies of the proteins. Currently, Dodecyl-B-D-maltopyranoside (DDM) is currently the most effective detergents for maintaining protein stability. This is due to the ...
Hi, I am trying to express in E. coli four different membrane proteins (ABC transporter) in either a pET vector with an N-terminal 6x his-tag or an pASK-IBA vector (tet promotor) with N- or C-terminal strep-tag, respectively. I tried different concentrations of inductor, different times of expression, different temperatures... Under all condition the proteins seem to be toxic (decrease in OD), and I cannot detect anything of the right size after fractionation and column purifcation or just fractionation western blotting, antibody detection. Has anyone an idea how I can get my proteins? Thanks for your advice! punzel http://biowww.net/mynews/tree.php?group_name=bionet_molbio_proteins&begin=0 ...
... - reflects the multidimensional character of chemical biology, focusing in particular on the fundamental science of biological structures and systems, the use of chemical and biological techniques to elucidate
Dear colleagues, please be informed that the registration slot for the 6th International NCCR Symposium on New Trends in Structural Biology 8 + 9 September 2008, University of Zürich, Lecture Hall KOH-B10, Zürich, Switzerland is now open. Online registration is possible directly from the symposium website: www.structuralbiology.uzh.ch/symposium2008.asp where you will also find further information about this event. Confirmed plenary lecturer to date: Stephen C. Kowalczykowski, Keiichi Namba, Poul Nissen, Andrej Sali, Titia Sixma, Jeffrey Skolnick, A. Joshua Wand Please do not hesitate to contact me anytime if you need further information (sticher from bioc.uzh.ch). With best regards, Patrick Sticher The NCCR Structural Biology is a research initiative of the Swiss Science Foundation. Its research encompasses the fields of recombinant protein technologies, macromolecular structure determination and computational biomolecular sciences with a special focus on membrane proteins and supramolecular ...
NIH Awards $14.5 Million, Five-Year Grant to Scripps Research - The new NIH grant funds work at Scripps Research that will enable structural biology research on membrane proteins, an area of research that has enormous medical potential.. ...
Mitochondria contain approximately 1200 different proteins, 99% of which are synthesized on cytosolic ribosomes and need to be delivered into the right destination through the intermembrane space by transport machineries, such as the TIM chaperone. Currently, the mechanistic and structural details of how the TIM chaperone binds to these mitochondrial proteins remain elusive. To gain structural insight into the binding and chaperone mechanisms, we focused on the complex of the TIM9/10 chaperone and the mitochondrial GDP/GTP carrier membrane protein (Ggc1). Such complexes are difficult to study because they consist of a transiently formed, dynamic complex between two folded proteins and a membrane protein that should be solubilized and bound by the chaperone. X-ray crystallography has revealed the core structure of the free chaperone protein, but because of the dynamic nature and large size (~1400 amino acids) of the complex its structural features have remained elusive. Using an integrative ...
Transmembrane proteins are gatekeepers of the cells; controlling the transport of substrates as well as communicating signals among cells and between the organelles and cytosol. Solute carriers (SLC) and G protein-coupled receptors (GPCR) are the largest family of membrane transporters and membrane receptors respectively. The overall aim of this thesis was to provide a basic understanding of some of the novel SLCs and GPCRs with emphasis on expression, transport property, evolution and probable function.. The first part of the thesis directs towards the study of some novel solute carriers. In an initial study, we provided an overall picture of the sequence relationship and tissue expression of 14 diverse atypical SLCs confirming some of their evolutionary conservation and highly specific expression pattern. The focus then was on the SLC17 family (mainly vesicular proteins) and a novel member named Slc17a9. This study revealed that SLC17 family could be divided into four main phylogenetic clades ...
We all know sushi rolls, but just to be sure here is an easy definition: a wrapper encircles rice which holds a precious bit of fish. To make a sushi role is an art and the same holds true for molecular sushi that is made of two lipoproteins as wrapper, lipids as rice, and membrane proteins as filling. Sushi rolls are for eating. Molecular sushi roles are for holding membrane proteins in place for physical analysis; they actually come only in sliced form, one disc at a time. Due to their size, the discs are called nanodiscs. Since membrane proteins are notoriously difficult to study experimentally due to their need to be in a "native" membrane environment, nanodiscs are a great tool, furnishing a membrane environment that has been used to embed a variety of membrane proteins for biochemical assay, including cytochrome P450s, rhodopsin, bacterial chemoreceptors, blood clotting factors, and translocation proteins. Unfortunately, it is difficult to make either real or molecular sushi rolls ...
... is a Python-based pipeline that integrates several tools the prediction of topology and subcellular localization of Eukaryotic membrane proteins.. The server is freely available, without registration. However, registered users, benefit of higher prediction priority and can log their job history. Please, be aware that anonymous submissions will be stored in the server and will be publicly available in the recent results section. For any request or bug report, please feel free to contact us. ...
G-Protein coupled receptors are transmembrane proteins that activate a signal transduction pathway which communicates within the cell. All GPCR antibodies are optimised for histochemistry in human tissues using formalin-fixed, paraffin embedded sections. Antibodies are provided as 50ug of peptide affinity-purified polyclonal rabbit sera. The expression pattern of eacj antibody has been screened across a panel of up to 50 tissues and compared to other proprietary or commercially available antibodies by board-certified pathologists. Antibodies are selected that show the strongest concordance to existing literature and known patterns of expression in other species, as well as for their affinity and specifically their targets. ...
Contact us today for a free consultation with the scientific team and discover how Creative Biogene can be a valuable resource and partner for your organization.. ...
For movement sporozoites need to be attached to a substrate, which can be either two- or three-dimensional. Unlike higher eukaryotic cells sporozoites migrate without changing their shape using a motility type termed gliding motility. Sporozoites can reach peak speeds of over 5 µm/s, which is ten times faster than the fastest cells in our bodies. Motility is mediated by molecular motor localized underneath the plasma membrane. This motor is linked to membrane proteins that span the plasma membrane. Sporozoites harbour at least three trans-membrane proteins, that could play a role in sticking to the substrate and thus to parasite movement. Recent results from our groups suggested for the first time a different function of two of these proteins depending on their location on the sporozoite surface (Hegge et al., 2012) and a possibly promiscuous use of binding partners on the substrate (Perschmann et al., 2011) to mediate adhesion and motility. However, the contributions of the individual ...
Recently synthesized proteins are sorted at the trans-Golgi network into specialized routes for exocytosis. Surprisingly little is known about the underlying molecular machinery. Here, we present a visual screen to search for proteins involved in cargo sorting and vesicle formation. We expressed a GFP-tagged plasma membrane protein in the yeast deletion library and identified mutants with altered marker localization. This screen revealed a requirement of several enzymes regulating the synthesis of sphingolipids and ergosterol in the correct and efficient delivery of the marker protein to the cell surface. Additionally, we identified mutants regulating the actin cytoskeleton (Rvs161p and Vrp1p), known membrane traffic regulators (Kes1p and Chs5p), and several unknown genes. This visual screening method can now be used for different cargo proteins to search in a genome-wide fashion for machinery involved in post-Golgi sorting ...
Surface receptors are integral membrane proteins to which certain signal molecules bind. They generally span the cell membrane, connecting the outside of the cell with the inside, enabling the inner workings of the cell to sense and respond to signals outside of the cell. Each surface receptor is specific with respect to the compound or compounds it will bind; a molecule that can bind to a given receptor is called a ligand for that receptor. When a ligand binds to its surface receptor, the internal portion of the receptor becomes modified in some manner, effectively communicating to the cell that the ligand is present. This then elicits some type of response, such as chemotaxis. ■ chemotaxis, p. 65. Cells can alter the types of surface molecules they make, enabling them to respond only to signals that are relevant when the cell is in a certain location or developmental stage. For example, a dendritic cell in the tissues would respond differently to certain stimuli than one that has migrated to ...
... , Authors: Atsuhiro Tanabe, Maho Saito. Published in: Atlas Genet Cytogenet Oncol Haematol.
Looking for online definition of peroxisomal membrane protein 2 in the Medical Dictionary? peroxisomal membrane protein 2 explanation free. What is peroxisomal membrane protein 2? Meaning of peroxisomal membrane protein 2 medical term. What does peroxisomal membrane protein 2 mean?
TY - JOUR. T1 - Differential roles of ionic, aliphatic, and aromatic residues in membrane - Protein interactions. T2 - A surface plasmon resonance study on phospholipases A2. AU - Stahelin, Robert. AU - Cho, W.. PY - 2001/4/17. Y1 - 2001/4/17. N2 - The roles of cationic, aliphatic, and aromatic residues in the membrane association and dissociation of five phospholipases A2 (PLA2), including Asp-49 PLA2 from the venom of Agkistodon piscivorus piscivorus, acidic PLA2 from the venom of Naja naja atra, human group IIa and V PLA2s, and the C2 domain of cytosolic PLA2, were determined by surface plasmon resonance analysis. Cationic interfacial binding residues of A. p. piscivorus PLA2 (Lys-10) and human group IIa PLA2 (Arg-7, Lys-10, and Lys-16), which mediate electrostatic interactions with anionic membranes, primarily accelerate the membrane association. In contrast, an aliphatic side chain of the C2 domain of cytosolic PLA2 (Val-97), which penetrates into the hydrophobic core of the membrane and ...
This study has revealed that the integral inner nuclear membrane protein Src1 functions in gene regulation of subtelomeric genes and is embedded functionally in a network of factors, which participate in transcription-coupled mRNA export. Importantly, Src1 is associated with subtelomeric chromatin and thus can help to organize this region of the chromosomes. In previous studies, Src1 was shown to contain an intron with the possibility of alternative splicing (Davis et al., 2000; Rodríguez-Navarro et al., 2002). Our study revealed that both splice forms localize to the nuclear periphery and are integral inner nuclear membrane proteins (King et al., 2006). However, both proteins are not functionally equivalent. To the best of our knowledge, this is the first demonstration that two forms of a protein generated by alternative splicing in yeast have different functions.. The N domain of Src1 mediates nuclear targeting, and insertion into the nuclear membrane requires the first transmembrane span. ...
The surface-accessible ectodomain region of the Plasmodium falciparum apical membrane antigen 1 (AMA1) is a malaria vaccine candidate. The amino acid sequence may be under selection from naturally acquired immune responses, and previous analyses with a small number of allele sequences indicate a non-neutral pattern of nucleotide variation. To investigate whether there is selection to maintain polymorphism within a population, and to identify the parts of the ectodomain under strongest selection, a sample of 51 alleles from a single endemic population was studied. Analyses using Fu and Lis D and F tests, Tajimas D test, and the McDonald-Kreitman test (with the chimpanzee parasite P. reichenowi as outgroup) show significant departure from neutrality and indicate the selective maintenance of alleles within the population. There is also evidence of a very high recombination rate throughout the sequence, as estimated by the recombination parameter, C, and by the rapid decline in linkage disequilibrium with
Looking for online definition of cystic fibrosis transmembrane conductance regulator gene in the Medical Dictionary? cystic fibrosis transmembrane conductance regulator gene explanation free. What is cystic fibrosis transmembrane conductance regulator gene? Meaning of cystic fibrosis transmembrane conductance regulator gene medical term. What does cystic fibrosis transmembrane conductance regulator gene mean?
Abbreviations: CAPS, calcyphosine; CISK, cytokine-independent survival kinase; DAG, diacylglycerol; DCV, dense core vesicle; DGK, DAG kinase; EEA1, early endosomal antigen 1; ENTH, epsin N-terminal homology; ER, endoplasmic reticulum; IP3, myo-inositol 1,4,5-trisphosphate; LUV, large unilamellar vesicle; NSF, N-ethylmaleimide-sensitive factor; PH domain, pleckstrin homology domain; PI3K, phosphoinositide 3-kinase; PIP, phosphoinositide phosphate; PIP5K, PtdIns4P 5-kinase; PKC, protein kinase C; PLA, phospholipase A; PLC, phospholipase C; PLD, phospholipase D; PI-PLC, phosphoinositide-specific PLC; PtdOH, phosphatidic acid; PX domain, Phox homology domain; SARA, Smad anchor for receptor activation; SNAP, soluble NSF-attachment protein; SNARE, SNAP receptor; SCAMP2, secretory carrier membrane protein 2; VAMP, vesicle-associated membrane protein ...
Tight junctions between epithelial and endothelial cells form selective barriers and paracellular channels and regulate paracellular transport of solutes, immune cells, and drugs. More specifically, tight junctions consist of proteins that laterally interconnect neighboring cells of epithelia and endothelia. Certain proteins seal the tight junction, so that a nearly impermeable barrier develops, whereas others form channels that allow for permeation between the cells. Recent investigations have focused on tight junction proteins, belonging to the claudin family (claudins-1 to -27 in humans) and the newly defined group of TAMP (three proteins: occludin, Marvel-D2, and tricellulin). Barriers and Channels Formed by Tight Junction Proteins I showcases work in this area clustered around three major themes: the molecular properties of tight junctions, for example, the role of the claudin family of proteins and the formation of ion and charge-selective channels; the regulation of tight junction
4.5 Protein targeting and import *4.5.1 Transport proteins and membrane translocons ... Outer chloroplast membrane. Main article: Chloroplast membrane. The outer chloroplast membrane is a semi-porous membrane that ... Inner chloroplast membrane. Main article: Chloroplast membrane. The inner chloroplast membrane borders the stroma and regulates ... All chloroplasts have at least three membrane systems-the outer chloroplast membrane, the inner chloroplast membrane, and the ...
... 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 ... "Sequence analysis of Arabidopsis thaliana E/ANTH-domain-containing proteins: membrane tethers of the clathrin-dependent vesicle ... Epsin contains various protein domains that aid in function. Starting at the N-terminus is the ENTH domain. ENTH stands for ...
Hsieh, CL; Kumar, NM; Gilula, NB; Francke, U (Mar 1991). "Distribution of genes for gap junction membrane channel proteins on ... The membrane from each cell is the dark line with the whiter narrow gap between the two darkly stained membranes. In such ... "Identification of a 70,000-D protein in lens membrane junctional domains". The Journal of Cell Biology. 101 (1): 28-35. doi: ... a protein from rat heart homologous to a gap junction protein from liver". The Journal of Cell Biology. 105 (6 Pt 1): 2621-9. ...
Ghosh, Raja (2002). "Protein separation using membrane chromatography: opportunities and challenges". Journal of Chromatography ... Membranes can be prepared through isolation of the membrane itself, where membranes are cut into squares and immobilized. A ... Membrane exchange chromatography[edit]. A type of ion exchange chromatography, membrane exchange[33][34] is a relatively new ... Thömmes, J., & Kula, M. R. (1995). Membrane chromatography-an integrative concept in the downstream processing of proteins. ...
... falciparum erythrocyte membrane protein-1 (PfMP-1).[12] This protein is the parasite's main cytoadherence ligand and virulence ... receptor (cellular surface) - specialized integral membrane proteins that take part in communication between the cell and the ... The Gerbich antigen system is an integral membrane protein of the erythrocyte and plays a functionally important role in ... Hempelmann E, Götze O (1984). "Characterization of membrane proteins by polychromatic silver staining". Hoppe-Seyler's Z ...
Membrane transport proteins such as the sodium-potassium pump within the membrane are equivalent to turbines that convert the ... "Membrane Physiology and Membrane Biophysics. 6: 29. doi:10.3389/fphys.2015.00029. PMC 4319557 . PMID 25705194.. ... Structural biochemistry and biophysics of membrane proteins. 1850 (3): 536-553. doi:10.1016/j.bbagen.2014.05.021.. ... When there are unequal concentrations of an ion across a permeable membrane, the ion will move across the membrane from the ...
EMP2: Epithelial membrane protein 2. *ENKD1: Enkurin domain-containing protein 1. *ERAF: Alpha-hemoglobin-stabilizing protein ... UNKL: encoding protein RING finger protein unkempt-like. *VAT1L: encoding protein Vesicle amine transport protein 1 homolog (T ... LINC00273 encoding protein Long intergenic non-protein coding RNA 273. *LOC124220: encoding protein Zymogen granule protein 16 ... SHCBP1: encoding protein SHC SH2 domain-binding protein 1. *SLZ1: encoding protein SLX1 structure-specific endonuclease subunit ...
In purple bacteria, such as Rhodospirillum rubrum, the light-harvesting proteins are intrinsic to the chromatophore membranes. ... Salton, MR (1987). "Bacterial membrane proteins". Microbiological sciences. 4 (4): 100-5. PMID 3153178. Frigaard, NU; Bryant, ... In some forms of photosynthetic bacteria, a chromatophore is a coloured, membrane-associated vesicle used to perform ...
Member 5, also known as SLC17A5 or sialin is a lysosomal membrane sialic acid transport protein which in humans is encoded by ... 2002). "Identification of a novel membrane protein, HP59, with therapeutic potential as a target of tumor angiogenesis". Clin. ... Winchester BG (2001). "Lysosomal membrane proteins". Eur. J. Paediatr. Neurol. 5 Suppl A: 11-9. doi:10.1053/ejpn.2000.0428. ... Solute carrier family 17 (anion/sugar transporter), member 5, also known as SLC17A5 or sialin, is a protein which in humans is ...
Nanodisc - water-soluble protein-stabilized lipid discs that can trap and stabilize membrane proteins. Bowie, J (2001). " ... Amphipol-trapped membrane proteins are, as a rule, much more stable than detergent-solubilized ones, which facilitates their ... Popot, J.-L. (2018) Membrane proteins in aqueous solutions: From detergents to amphipols. Springer, New York, in the press. ... Amphipols (a portmanteau of amphiphilic polymers) are a class of amphiphilic polymers designed to keep membrane proteins ...
Palmitoylation is important for membrane localisation of many proteins. Applications[edit]. Palmitic acid is used to produce a ... some proteins are modified by the addition of a palmitoyl group in a process known as palmitoylation. ...
In molecular biology caveolins are a family of integral membrane proteins that are the principal components of caveolae ... All three members are membrane proteins with similar structure. Caveolin forms oligomers and associates with cholesterol and ... Caveolins may act as scaffolding proteins within caveolar membranes by compartmentalizing and concentrating signaling molecules ... Both the C-terminus and the N-terminus face the cytoplasmic side of the membrane. There are two isoforms of caveolin-1: ...
... performs this function by specifically binding to ergosterol and inhibiting membrane transport proteins.[14] ... Polyene antibiotic that inhibits membrane transport proteins. Proc. Natl. Acad. Sci. U. S. A. 2012, 109, 11156-11159. ... Natamcyin is able to inhibit growth of fungi by inhibiting transport of amino acids and glucose across the plasma membrane. ... It results in fungal death by altering the cell membrane.[1] ...
... 1, Lysosomal-associated membrane protein 1. *LAMP2, Lysosomal-associated membrane protein 2 ... Lysosome-associated membrane glycoprotein. Organisations[edit]. *Lutheran Association of Missionaries and Pilots, a cross- ... LAMP3, Lysosomal-associated membrane glycoprotein 3. *All pages with a title containing lamp, includes many other forms of lamp ...
Orientations of Proteins in Membranes database. *Opportunistic Mesh, a wireless networking technology ...
"Electrostatic binding of proteins to membranes. Theoretical predictions and experimental results with charybdotoxin and ...
VAPB: VAMP (vesicle-associated membrane protein)-associated protein B and C. *YTHDF1: encoding protein YTH domain family, ... encoding protein Transmembrane prostate androgen-induced protein. *TTPAL: encoding protein Tocopherol (alpha) transfer protein- ... FASTKD5: encoding protein FAST kinase domain-containing protein 5 (FASTKD5). *FITM2: encoding protein Fat storage-inducing ... BPIFB4: encoding protein BPI fold containing family B, member 4. *C20orf132: encoding protein Uncharacterized protein C20orf132 ...
1991). Crystallization of membrane proteins. CRC Press. M Caffrey (2003). "Membrane protein crystallization". J. Struct. Biol. ... For membrane proteins, the situation is more complicated because the system that is being crystallized is not the membrane ... protein itself but the micellar system in which the membrane protein is embedded. The size of the protein-detergent mixed ... By reducing the size of the mixed micelles lattice forming protein-protein contacts are encouraged. Lipid cubic phases, ...
Kir channels are formed from as homotetrameric membrane proteins. Each of the four identical protein subunits is composed of ... UMich Orientation of Proteins in Membranes families/family-85 - Spatial positions of inward rectifier potassium channels in ... By mediating a small depolarizing K+ current at negative membrane potentials, they help establish resting membrane potential, ... pushing the membrane potential back to the resting potential. This can be seen in figure 1: when the membrane potential is ...
In addition to serving as a primary component of cellular membranes and binding sites for intra- and intercellular proteins, ... as the cellular plasma membrane and the intracellular membranes of organelles; in animal cells, the plasma membrane physically ... Membranes[edit]. Eukaryotic cells feature the compartmentalized membrane-bound organelles that carry out different biological ... Molecular Computer Simulations - Modeling of Lipid Membranes. *Lipids, Membranes and Vesicle Trafficking - The Virtual Library ...
FTIR is used to investigate proteins in hydrophobic membrane environments. Studies show the ability of FTIR to directly ... Brielle, Esther S.; Arkin, Isaiah T. (2018). "Site-Specific Hydrogen Exchange in a Membrane Environment Analyzed by Infrared ... single viruses and protein complexes) and with 10 to 20 nm spatial resolution.[13] ... "Environment Polarity in Proteins Mapped Noninvasively by FTIR Spectroscopy". The Journal of Physical Chemistry Letters. 3 (7 ...
Proteins that have a greater hydrophobic content - for instance, many membrane proteins, and those that interact with ... For proteins, sodium dodecyl sulfate (SDS) is an anionic detergent applied to protein samples to coat proteins in order to ... 2-Dimensional Protein Gelelectrophoresis. *[1] Hempelmann E. SDS-Protein PAGE and Proteindetection by Silverstaining and ... Separating gels allow for the separation of proteins and have a relatively lower porosity. Here, the proteins are separated ...
Both proteins are associated with cell membranes.[4] p41 (capsid protein)[edit]. The viral capsid protein CP, or p41, is a ... The p22 protein is a movement protein that is required for the virus to spread from cell to cell. P22 is an RNA-binding protein ... a capsid protein (called CP or p41), and two additional proteins, the RNA silencing suppressor p19 and movement protein p22.[4] ... P33 proteins cooperatively bind single-stranded nucleic acids, while the p92 protein is a RNA-dependent RNA polymerase (RdRp). ...
... affects the function of membrane proteins by binding to the specific site on the protein. Thus, some membrane proteins are ... Each bilayer membrane has a distinct profile of how lateral pressures are distributed within it. Most membrane proteins ( ... by modulating the activity of membrane proteins in the neuronal membrane. However, the exact location and mechanism of this ... Membrane protein hypothesis of general anaesthetic action[edit]. Inhaled general anaesthetics frequently do not change ...
protein transporter activity. Cellular component. • integral component of membrane. • mitochondrial inner membrane. • membrane ... protein transport. • protein folding. • visual perception. • genitalia development. • protein targeting to mitochondrion. • ... "Mitochondrial import inner membrane translocase subunit TIM14". Cardiac Organellar Protein Atlas Knowledgebase (COPaKB).. ... CL is a key phospholipid in mitochondrial membranes that modulates the fusion and fission of mitochondrial membranes, as well ...
LVEM experiments carried out on an extracted membrane protein sample that was analyzed with and without the staining procedure ... Lundstrom, Kenneth (2006). Structural genomics on membrane proteins. CRC Press. pp. 271-274. ISBN 1-57444-526-X. Van Aken, R. H ... as a probe for solubilized membrane protein aggregation states". Microscopy and Microanalysis. 10 (2): 1492-1493. doi:10.1017/ ... it is highly undesirable in certain protein sample preparations, because it could destabilize the protein sample due to its ...
... from membrane currents, proteins, and chemical coupling to network oscillations, columnar and topographic architecture, and ... "A quantitative description of membrane current and its application to conduction and excitation in nerve". J. Physiol. 117 (4 ...
The alternative oxidase is an integral monotopic membrane protein that is tightly bound to the inner mitochondrial membrane ... Berthold DA, Stenmark P (2003). "Membrane-bound diiron carboxylate proteins". Annual Review of Plant Biology. 54: 497-517. doi: ... Proteins homologous to the mitochondrial oxidase have also been identified in bacterial genomes. The oxidase provides an ... Electron transport proteins InterPro entry on alternative oxidases alternative oxidase at the US National Library of Medicine ...
... lysosomal-associated membrane protein (LAMP) 2A, although whether LAMP2A is the only LAMP2 isoform affected by PD is unknown. ... lysosomal-associated membrane protein (LAMP) 2A, although whether LAMP2A is the only LAMP2 isoform affected by PD is unknown. ... with LAMP2B and LAMP2C protein levels also unchanged in PD. The selective loss of LAMP2A protein directly correlated with the ... with LAMP2B and LAMP2C protein levels also unchanged in PD. The selective loss of LAMP2A protein directly correlated with the ...
Effect of Temperature on Beetroot Membrane Proteins 4 star(s) With carrier proteins gone, more substances within the cell can ... Investigating the effect of temperature on cell membrane permeability To investigate the effect of temperature on cell membrane ... How Temperature Effects the Movement of Pigment Through Cell Membranes 0.03 0.03 0.05 0.05 0.10 0.30 0.55 1.20 This shows that ... The factors affecting the rate of permeability in a cell membrane? The diffusion of water through a partially permeable ...
integral membrane protein type of membrane protein that is permanently attached to the biological membrane ... Media in category "Integral membrane proteins". The following 15 files are in this category, out of 15 total. ... Dynamic-Organization-of-SecA-and-SecY-Secretion-Complexes-in-the-B.-subtilis-Membrane-pone.0157899.s010.ogv 1 min 59 s, 120 × ... Retrieved from "https://commons.wikimedia.org/w/index.php?title=Category:Integral_membrane_proteins&oldid=312353638" ...
Shedding of plasma membrane proteins.. Arribas J1, Merlos-Suárez A.. Author information. 1. Laboratori de Recerca Oncològica, ...
... in many integral membrane proteins they comprise a significantly higher proportion of the amino acid composition. Now that... ... While tryptophans are generally found in low abundance in soluble proteins, ... While tryptophans are generally found in low abundance in soluble proteins, in many integral membrane proteins they comprise a ... Oligopeptide biases in protein sequences and their use in predicting protein coding regions in nucleotide-sequences, Proteins: ...
Crystallizing membrane proteins using lipidic mesophases.. Caffrey M1, Cherezov V.. Author information. 1. Membrane Structural ... A flow chart summarizing the steps involved in and time required for setting up an in meso membrane protein crystallization ... Crystals of membrane proteins growing in the lipidic mesophase. A, bacteriorhodopsin; B, light harvesting complex II; C, the ... Cartoon representation of the events proposed to take place during the crystallization of an integral membrane protein from the ...
Membrane proteins represent about one third of the proteins encoded in a cells genome, and, because of their key physiological ... Amphipols Reviewed Membrane Protein Folding Membrane Protein Stability Membrane Protein Structural Studies Membrane Protein ... Membrane proteins represent about one third of the proteins encoded in a cells genome, and, because of their key physiological ... Topical chapters cover in vitro folding, cell-free synthesis and stabilization of membrane proteins, and such biophysical and ...
Membrane Protein Labeling, Imaging and Functional Characterization, with Howard Hughes Medical Institute (HHMI). Apply Today. ... Research Specialist - Membrane Protein Labeling, Imaging and Functional Characterization. Howard Hughes Medical Institute (HHMI ... Optimize high-throughput genome-editing methods to tag and label endogenous membrane proteins in the brain (mouse). ... super-resolution and electron microscopy pipeline to map and annotate the sub-cellular localization of membrane proteins in the ...
Orientations of Proteins in Membranes (OPM) database provides spatial positions of membrane protein structures with respect to ... membrane topology, quaternary structure of proteins in membrane-bound state, and the type of a destination membrane for each ... Orientations of Proteins in Membranes. Content. Description. The database provides spatial arrangement of proteins in the lipid ... Proteins structures are taken from the Protein Data Bank. OPM also provides structural classification of membrane-associated ...
Postdoctoral position in Membrane Protein Structure / Protein NMR. *Postdoctoral position in Molecular Biophysics / NMR-based ... Postdoctoral position in Membrane Protein Structure / Protein NMR. *Postdoctoral position in Molecular Biophysics / NMR-based ... Postdoctoral Position in Membrane Protein NMR at TUM / Helmholtz Center Munich. *Postdoctoral Position in Metabolic MRI - ... Postdoctoral Position in Membrane Protein NMR at TUM / Helmholtz Center Munich. *Postdoctoral Position in Metabolic MRI - ...
Determinants of membrane protein topology. D Boyd, C Manoil, and J Beckwith ... The topology of the integral membrane protein MalF, which is required for maltose transport in Escherichia coli, has been ... These studies in conjunction with our earlier results show that alkaline phosphatase fusions to membrane proteins can be an ... of the cytoplasmic domains of membrane proteins are important in anchoring these domains in the cytoplasm. ...
... latent membrane protein 2 (LMP2) are two viral proteins of the Epstein-Barr virus. LMP2A/LMP2B are transmembrane proteins that ... "The Epstein-Barr virus latent membrane protein 2A PY motif recruits WW domain-containing ubiquitin-protein ligases". Virology. ... Twelve membrane spanning segments ending with a short 28 residue COOH tail are common to both proteins in residue 379. The 119 ... Latent Membrane Protein 2 (LMP2) is a rightward transcribing gene. LMP2s transcript originates across the fused terminal ...
... rajneeli rajneeli at lebs.cnrs-gif.fr Thu Feb 28 09:30:26 EST 2002 *Previous message: 1/5X TE for long term ... Hi netters I have specific problem in extraction of membrane protein. When I use Triton X-100, it decreases enzyme activity by ...
Centre of Membrane Proteins and Receptors. The Centre of Membrane Proteins and Receptors (COMPARE) is a unique collaboration ... COMPARE works to develop novel methods for visualising single membrane proteins, as well as identifying new approaches for the ... New algorithms and mathematical models of signalling by G Protein-Coupled Receptors (GPCR) and Tyrosine Kinase-linked Receptors ... development of a new generation of drugs with reduced side effects by virtue of targeting receptors in their unique membrane ...
... stabilization and structural analysis techniques of membrane proteins Explores the structural ... Membrane Proteins Production for Structural Analysis. Editors. * Isabelle Mus-Veteau Copyright. 2014. Publisher. Springer- ... Overexpression of Membrane Proteins in Saccharomyces cerevisiae for Structural and Functional Studies: A Focus on the Rabbit ... Isabelle Mus-Veteau is a biochemist and biophysicist specialist in membrane protein characterization. She obtained her PhD in ...
... Cédric Pety de Thozée and Michel Ghislain ... Cédric Pety de Thozée and Michel Ghislain, "ER-Associated Degradation of Membrane Proteins in Yeast," TheScientificWorldJOURNAL ...
Intrinsically curved proteins or protein oligomers can provide "scaffolding" that leads to membrane bending; partially membrane ... The peripheral membrane protein M1 is considered not to have membrane subdomain specificity. In the next paragraphs, we ... The matrix protein M1 (red in Figure 1) binds to membranes, but does not have a transmembrane span [9-11]. M1 is most likely ... M1 can fulfill this function by being transported to the plasma membrane by the other viral membrane proteins (see above). Of ...
"Discovery Links Proteins Necessary To Repair Membranes." Medical News Today. MediLexicon, Intl., 11 Jun. 2009. Web.. 20 Jan. ... Linking these proteins creates a mechanism that allows damaged membranes to be repaired, which may transform treatment for ... 2009, June 11). "Discovery Links Proteins Necessary To Repair Membranes." Medical News Today. Retrieved from. https://www. ... His research team announced in December 2008 that it had discovered MG53 as a key initiator of membrane repair in damaged ...
... Christian Ebeling cebelin at gwdg.de Fri Sep 19 22:23:47 EST 1997 *Previous message: First ... Hello, i need for my project membran proteins from any organism which forms a specific heterodimer with a strong affinity. This ...
Postdoctoral position in Membrane Protein Structure / Protein NMR. *Postdoctoral position in Molecular Biophysics / NMR-based ... Postdoctoral position in Membrane Protein Structure / Protein NMR. *Postdoctoral position in Molecular Biophysics / NMR-based ... Postdoctoral Position in Membrane Protein NMR at TUM / Helmholtz Center Munich. *Postdoctoral Position in NMR Methods ... Postdoctoral Position in Membrane Protein NMR at TUM / Helmholtz Center Munich. *Postdoctoral Position in NMR Methods ...
We combine protein signatures from a number of member databases into a single searchable resource, capitalising on their ... InterPro provides functional analysis of proteins by classifying them into families and predicting domains and important sites ... This family consists of putative outer membrane proteins, mainly from H. pylori. ... Potential targets for vaccine development are H. pylori-specific proteins that are surface-exposed and highly antigenic. ...
Purchase Membrane Protein-Cytoskeleton Interactions, Volume 43 - 1st Edition. Print Book & E-Book. ISBN 9780121533434, ... and in regulating membrane protein, and ultimately, cell function. This volume reviews the regulation of membrane protein ... Membrane-Cytoskeleton Interactions with Cadherin Cell Adhesion Proteins; Roles of Catenins as Linker Proteins. ... G.G. Gayer, J.T. Campanelli, and R.H. Scheller, Regulation of Membrane Protein Organization at the Neuromuscular Junction. ...
How proteins fold is a fundamental problem in molecular biology and has been the subject of intense study. Membrane protein ... Methods to measure the thermodynamic stability of membrane proteins have largely followed methods developed for soluble protein ... the stability of other membrane proteins to see if high thermodynamic stability is common among helical membrane proteins, and ... helical membrane protein.. The steric trapping approach is outlined in Fig. 1. Two biotin tags are placed on the protein at ...
... expression of membrane proteins in heterologous systems is challenging. ... Due to unique physical properties and requirement for association with cellular membranes, ... Purification Expression of Difficult Proteins Membrane Protein Expression Membrane Protein Expression. Product Listing ... expression of membrane proteins in heterologous systems is often daunting.. Cellular expression of recombinant membrane protein ...
University of Toronto scientists have discovered a better way to extract proteins from the membranes that encase them, making ... "We believe this approach can be applied to many more membrane proteins, which would drastically speed up structure discovery of ... University of Toronto scientists have discovered a better way to extract proteins from the membranes that encase them, making ... Currently, researchers use detergents to separate proteins from their fatty membrane casing for further in-detail studies. But ...
  • Specific dysfunction of chaperone-mediated autophagy (CMA) in PD is suggested by reductions in the CMA membrane receptor, lysosomal-associated membrane protein (LAMP) 2A, although whether LAMP2A is the only LAMP2 isoform affected by PD is unknown. (garvan.org.au)
  • Lysosomes are the primary catabolic compartment for the degradation of intracellular proteins through autophagy. (garvan.org.au)
  • Our data show that LAMP2 protein isoforms are differentially affected in the early stages of PD, with LAMP2A selectively reduced in association with increased alpha-synuclein, and suggests that dysregulation of CMA-mediated protein degradation occurs before substantial alpha-synuclein aggregation in PD. (garvan.org.au)
  • Bacterial proteins with MCE domains were first described as being important for M ammalian C ell E ntry. (nature.com)
  • Bioinformatic analyses revealed that MCE domains are widely distributed across bacterial phyla but multi MCE domain-containing proteins evolved in Proteobacteria from single-domain proteins. (nature.com)
  • Also, these peptides cause bacterial membrane permeabilization and damage of the bacterial envelope of P. aeruginosa cells. (frontiersin.org)
  • In addition, the AFM (located in the Centre for Cell Imaging) is used to explore the assembly dynamics of bacterial microcompartment shell proteins and the formation process of shell facets. (news-medical.net)
  • A NIST-developed model of a simplified cell membrane has been discovered by researchers, which may now accurately detect and measure protein associated with bacterial vaginosis. (medindia.net)
  • Collaborate closely with imaging tool builders at Janelia to develop super-resolution and electron microscopy pipeline to map and annotate the sub-cellular localization of membrane proteins in the brain. (nature.com)
  • However, due to their unique physical properties and requirement for association with cellular membranes, expression of membrane proteins in heterologous systems is often daunting. (neb.com)
  • Most water-soluble proteins can readily be produced either within modified cell lines or through the use of cellular extracts that contain the full complement of machinery required for protein synthesis. (riken.jp)
  • The investigators behind the new study worked around that problem by using the small cellular protein saposin. (eurekalert.org)
  • Profilee Satyajit Mayor discusses his explorations of cell membranes, which are helping to update the classical fluid mosaic model of dynamic cellular boundaries. (the-scientist.com)
  • and mixing the intracytoplasmic membranes with the template and a transcription/translation-competent cellular extract to cause simultaneous production of the membrane proteins and encapsulation of the membrane proteins within the intracytoplasmic membranes. (osti.gov)
  • Autophagy (particularly macroautophagy) is a bulk degradation process used by eukaryotic cells in order to maintain adequate energy levels and cellular homeostasis through the delivery of long-lived proteins and organelles to the lysosome, resulting in their degradation. (mdpi.com)
  • The heterogeneity of biological membranes plays an important role in cellular function. (rug.nl)
  • The reversible attachment of proteins to biological membranes has shown to regulate cell signaling and many other important cellular events, through a variety of mechanisms. (wikidoc.org)
  • Membrane proteins play pivotal roles in a wide variety of cellular processes, and as such are key targets for drug discovery (e.g. (thermofisher.com)
  • Orientations of Proteins in Membranes (OPM) database (base de datos Orientacións de Proteínas en Membranas) é unha base de datos que proporciona as posicións espaciais das estruturas das proteínas de membrana na bicapa lipídica . (wikipedia.org)
  • Membrane enzymes may have many activities, such as oxidoreductase, transferase or hydrolase. (wikipedia.org)
  • Membrane enzymes have many activities. (wikipedia.org)
  • This class of proteins includes enzymes such as monoamine oxidase and fatty acid amide hydrolase . (wisegeek.com)
  • The immobilization of enzymes (for biocatalysis) and specific protein channels (for selective transport) is an important area of research where both selective separations and reactivity is needed. (uky.edu)
  • Design and perform electrophysiology experiments to validate the function of the tagged protein in cultured cells or in brain slices. (nature.com)
  • HA assembles into a homotrimer in the ER and is transported via the secretory pathway to the plasma membrane, more specifically the apical plasma membrane in polarized (e.g., epithelial) cells, where virus assembly and budding take place [ 2 ]. (hindawi.com)
  • Integral membrane proteins constitute a significant fraction of the proteome of all living cells. (neb.com)
  • University of Toronto scientists have discovered a better way to extract proteins from the membranes that encase them, making it easier to study how cells communicate with each other to create human health and disease. (eurekalert.org)
  • Zacharias, D.A., Violin, J.D., Newton, A.C. and Tsien, Y.R. (2002) Partitioning of lipid-modified monomeric GFPs into membrane microdomains of live cells. (scirp.org)
  • Proteins can be responsible for the fact that the active ingredients of drugs are simply released from the target cells. (phys.org)
  • However, the yield of membrane proteins obtained from cultured cells is generally inadequate, and scientists have had to tinker extensively with extract-based production methods to obtain usable quantities of functional protein. (riken.jp)
  • One-third of all tumours contain cells with mutations of Ras proteins. (mpg.de)
  • Both structurally and functionally, they are integral parts of the membranes of cells. (wisegeek.com)
  • Examples of integral transmembrane proteins include voltage-gated ion channels such as those which transport potassium ions in and out of cells. (wisegeek.com)
  • The research team, led by Dr. Isabel Fabregat, who is a professor at the Faculty of Medicine and Health Sciences of the University of Barcelona and a researcher at the CIBER of Hepatic and Digestive Diseases, has shown that liver cells with invasive features have high levels of clathrin, a protein whose involvement in liver cancer was unknown until now. (news-medical.net)
  • When membrane proteins are produced in E. coli , they overload the cell's bi-layers and cause the cells to die. (medgadget.com)
  • He also discusses whether experiments showing correlation of changes in plasma membrane cholesterol with differentiation and the formation of adherens junctions in endothelial cells are consistent with a model in which lipid rafts influence the regulation of these processes. (sciencemag.org)
  • To create the bionanoelectronic platform the LLNL team turned to lipid membranes, which are ubiquitous in biological cells. (medgadget.com)
  • Cells were incubated with a membrane-impermeable bivalent ligand (biotin-PEG2000-DIR) consisting of biotin joined to a dimethyl-indole red (DIR) fluorogen by a polyethylene glycol linker, thus tethering the fluorogen to the scAvd-FRB fusion protein. (medworm.com)
  • Epithelial membrane protein 2 (EMP2), a tetraspan protein that promotes recruitment of integrins to lipid rafts, is highly expressed in AT1 cells but has no known function in lung biology. (jci.org)
  • Taken together, we propose that EMP2-dependent membrane organization ensures proper display on AT1 cells of a suite of proteins required to instruct paracellular neutrophil traffic into the alveolus. (jci.org)
  • Together with our experimental collaborator Bert Poolman , we aim to unravel the lipid-mediated driving forces underlying protein sorting and clustering, and predict physical mechanisms that could be relevant in real cells. (rug.nl)
  • DNA-binding proteins in cells and membrane blebs of Neisseria gonorrhoeae. (asm.org)
  • The Thermo Scientific Mem-PER Plus Membrane Protein Extraction Kit enables small-scale solubilization and enrichment of integral and membrane-associated proteins from cultured cells and tissues using a simple reagent-based procedure and a bench-top microcentrifuge (Figure 1). (thermofisher.com)
  • Schematic presentation of the membrane protein extraction work flow with Mem-PER Plus Membrane Protein Extraction Kit from the mammalian cells. (thermofisher.com)
  • First, the cells are permeabilized with a mild detergent containing the Permeabilization Buffer, with the aim to liberate soluble cytosolic proteins. (thermofisher.com)
  • Synaptophysin is the first protein and most abundant ever found on the membranes surrounding the tiny sacs that carry chemical messengers to synapses, the gaps where communication between nerve cells occurs. (healthcanal.com)
  • To complement studies that have demonstrated the prominent phosphorylation of a 50-kD coated vesicle polypeptide in vitro, we have evaluated the phosphorylation of coated membrane proteins in intact cells. (rupress.org)
  • Although the brain AP50 is prominently phosphorylated by an endogenous protein kinase in isolated coated vesicle preparations, the neuronal AP50 was not detectably phosphorylated in intact cells as assessed by two-dimensional non-equilibrium pH gradient gel electrophoresis of labeled cells dissolved directly in SDS-containing buffers. (rupress.org)
  • Lemo21(DE3) allows researchers to sample a wide range of expression levels to find the optimal conditions for each unique target protein. (neb.com)
  • The researchers then demonstrated the efficacy of their technique with bacteriorhodopsin (BR), an archaea-derived photosynthetic pigment protein. (riken.jp)
  • Researchers at Karolinska Institutet, Sweden, have developed a nanoparticle technology that can be used to stabilise membrane proteins so that their structure can be studied in a lipid environment. (eurekalert.org)
  • The problem that researchers face is that these proteins are very unstable and therefore hard to investigate. (eurekalert.org)
  • Researchers studying water-soluble proteins often use commercial E. coli -based systems to express, or produce, copies of the protein. (medgadget.com)
  • Researchers will test the reagents on the membrane proteins produced in the Rhodobacter 'factory. (medgadget.com)
  • 1. A method for increasing the probability that a mammalian offspring will be female or male comprising the step of immunizing a female mammal with a Y-SAM protein or an X-SAM protein, respectively. (google.com)
  • The field of this invention is the isolation of novel proteins and their use in methods to increase the probability that mammalian offspring produced by it will be of a desired sex or carry a gone for a particular sex-chromosome linked trait. (google.com)
  • Three mammalian SCAMPs (secretory carrier membrane proteins) are highly related products of distinct genes having similar subcellular distributions. (jax.org)
  • There are three transmembraneous viral proteins embedded in the envelope: the glycoproteins hemagglutinin (HA) and neuraminidase (NA), which protrude at the viral surface as "spikes," and-in minor quantities-the proton channel protein M2. (hindawi.com)
  • Eight exons of LMP2 isoforms encode 12 membrane spanning segments that are connected by short hydrophilic loops and ends with a 27 amino acid cytoplasmic C-terminus domain. (wikipedia.org)
  • After removal of the soluble fraction containing hydrophilic proteins, the membrane proteins are extracted from the insoluble fraction using the Membrane Solubilization Buffer. (thermofisher.com)
  • In persons with cystic fibrosis this transport protein, known as the sodium-potassium pump, abnormally transports sodium ions across the membrane without carrying the chloride ions that usually accompany them. (jrank.org)
  • Therefore, it was deduced that a protein existed on the plasma membrane which actively pumped the two ions against their biological gradients. (wikibooks.org)
  • This phosphorylation causes a change in the 3D shape of the protein, making it open up to the extracellular world, and decreases the protein's affinity for sodium ions. (wikibooks.org)
  • This 'shielded wire' configuration allows us to use membrane pores as the only pathway for the ions to reach the nanowire," Noy said. (medgadget.com)
  • Added 'precipitants' shift the equilibrium away from stability in the cubic membrane. (nih.gov)
  • Here, we summarize the experimental evidence for this model with emphasis on the raft-targeting features of HA, NA, and M2 and review the functional importance of raft domains for viral protein transport, assembly and budding, environmental stability, and membrane fusion. (hindawi.com)
  • The thermodynamic stability of proteins is typically measured at high denaturant concentrations and then extrapolated back to zero denaturant conditions to obtain unfolding free energies under native conditions. (pnas.org)
  • We therefore sought to measure stability under native conditions, using a method that does not perturb the properties of the membrane or membrane mimetics. (pnas.org)
  • Methods to measure the thermodynamic stability of membrane proteins have largely followed methods developed for soluble protein folding ( 1 ). (pnas.org)
  • However, although there is now considerable experimental and theoretical validation of this approach for soluble proteins ( 2 ⇓ - 4 ), the validity of these extrapolations is not clear for measuring stability of membrane proteins. (pnas.org)
  • We introduced SDS unfolding to measure the thermodynamic stability of the membrane enzyme diacylglycerol kinase ( 9 ) and a similar approach can be used to measure bR thermodynamic stability ( 10 , 11 ). (pnas.org)
  • Helical membrane protein folding, stability, and evolution. (thefullwiki.org)
  • This postdoctoral position is part of a project where we investigate the structure of membrane-coupled proteins of the Bcl-2 family by using mainly solid-state NMR methods (complementary also neutron scattering approaches). (weizmann.ac.il)
  • Previous extensive experience of protein structure determination by solid-fast NMR is required and previous experience with membrane proteins is highly meriting. (weizmann.ac.il)
  • For membrane proteins, the extrapolations are fraught with considerable uncertainty as the denaturants may have complex effects on the membrane or micellar structure. (pnas.org)
  • Dr. Jana Broecker, a postdoctoral fellow in the lab of Professor Oliver P. Ernst, discovered that she could use a type of plastic, or polymer, originally developed by the auto industry, to better stabilize these crucial proteins and thereby make them available for 3D structure determination. (eurekalert.org)
  • We believe this approach can be applied to many more membrane proteins, which would drastically speed up structure discovery of currently unknown membrane proteins," says Broecker. (eurekalert.org)
  • The last model system was another integral membrane protein with a distinct structure but also a different function. (diva-portal.org)
  • Compared to other classes of proteins, the determination of membrane protein structure s has remained a challenge in large part due to the difficulty in establishing experimental conditions where the correct conformation of the protein in isolation from its native environment is preserved. (wikipedia.org)
  • Until now, it has been assumed that these functions underlie a static structure of mitochondrial membranes. (phys.org)
  • On the other hand, experimental investigation of the structure and function of individual membrane proteins is routinely thwarted by the general difficulty of preparing large quantities of properly folded protein. (riken.jp)
  • One way to figure out how a protein functions is to determine its structure. (newswise.com)
  • However, all membranes do have the same basic structure. (jrank.org)
  • The photosynthetic reaction center is a membrane protein as well - the very first membrane protein whose structure could be elucidated. (lindau-nobel.org)
  • We proposed to apply a chemical cross-linking, mass spectrometry and modeling method called MS3D to the structure determination of the rhodopsin-transducin membrane protein complex (RTC). (unt.edu)
  • Herein we describe experimental progress made to adapt the MS3D approach for characterizing membrane protein systems, and computational progress in experimental design, data analysis and protein structure modeling. (unt.edu)
  • Yarov-Yarovoy V, Schonbrun J, Baker D. (2006 Mar 1) Multipass membrane protein structure prediction using Rosetta. (rosettacommons.org)
  • Another important factor is that none of these amino acids are charged, so swapping them appears to have a minimal effect on the overall protein structure. (phys.org)
  • They also indicate that phosphorylation of the 100-110-kD AP may be involved in the regulation of coated membrane structure and function. (rupress.org)
  • Variation in the surrounding model environments for these four different types of membrane layer can affect the three-dimensional structure of reconstituted proteins and may possibly lead to loss of the proteins activity. (mdpi.com)
  • Carrier proteins are involved in using the energy released from ATP being broken down to facilitate active transport and ion exchange. (phys.org)
  • Cytochrome b5 is a membrane bound hemoprotein which function as an electron carrier for several membrane bound oxygenases. (abcam.com)
  • Of the given choices, only channel and carrier proteins allow substances to cross the membrane. (varsitytutors.com)
  • Therefore, this type of membrane traffic is called active transport. (wikibooks.org)
  • In particular, isolation procedures needed for in-depth studies of an individual type of membrane protein is complicated by the high tendency of membrane proteins to lose function upon detergent-based solubilization procedures. (chalmers.se)
  • Mapping the human membrane proteome: a majority of the human membrane proteins can be classified according to function and evolutionary origin. (wikipedia.org)
  • Aqueous-polymer two-phase system technique, microsomal and full proteome fractions, protein identification. (scielo.br)