Intermediate Filaments: Cytoplasmic filaments intermediate in diameter (about 10 nanometers) between the microfilaments and the microtubules. They may be composed of any of a number of different proteins and form a ring around the cell nucleus.Myosins: A diverse superfamily of proteins that function as translocating proteins. They share the common characteristics of being able to bind ACTINS and hydrolyze MgATP. Myosins generally consist of heavy chains which are involved in locomotion, and light chains which are involved in regulation. Within the structure of myosin heavy chain are three domains: the head, the neck and the tail. The head region of the heavy chain contains the actin binding domain and MgATPase domain which provides energy for locomotion. The neck region is involved in binding the light-chains. The tail region provides the anchoring point that maintains the position of the heavy chain. The superfamily of myosins is organized into structural classes based upon the type and arrangement of the subunits they contain.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.Intermediate Filament Proteins: Filaments 7-11 nm in diameter found in the cytoplasm of all cells. Many specific proteins belong to this group, e.g., desmin, vimentin, prekeratin, decamin, skeletin, neurofilin, neurofilament protein, and glial fibrillary acid protein.Microvilli: Minute projections of cell membranes which greatly increase the surface area of the cell.Actin Cytoskeleton: Fibers composed of MICROFILAMENT PROTEINS, which are predominately ACTIN. They are the smallest of the cytoskeletal filaments.Vimentin: An intermediate filament protein found in most differentiating cells, in cells grown in tissue culture, and in certain fully differentiated cells. Its insolubility suggests that it serves a structural function in the cytoplasm. MW 52,000.Cytoskeleton: The network of filaments, tubules, and interconnecting filamentous bridges which give shape, structure, and organization to the cytoplasm.Desmin: An intermediate filament protein found predominantly in smooth, skeletal, and cardiac muscle cells. Localized at the Z line. MW 50,000 to 55,000 is species dependent.Actin Depolymerizing Factors: A family of low MOLECULAR WEIGHT actin-binding proteins found throughout eukaryotes. They remodel the actin CYTOSKELETON by severing ACTIN FILAMENTS and increasing the rate of monomer dissociation.Keratins: A class of fibrous proteins or scleroproteins that represents the principal constituent of EPIDERMIS; HAIR; NAILS; horny tissues, and the organic matrix of tooth ENAMEL. Two major conformational groups have been characterized, alpha-keratin, whose peptide backbone forms a coiled-coil alpha helical structure consisting of TYPE I KERATIN and a TYPE II KERATIN, and beta-keratin, whose backbone forms a zigzag or pleated sheet structure. alpha-Keratins have been classified into at least 20 subtypes. In addition multiple isoforms of subtypes have been found which may be due to GENE DUPLICATION.Microfilament Proteins: Monomeric subunits of primarily globular ACTIN and found in the cytoplasmic matrix of almost all cells. They are often associated with microtubules and may play a role in cytoskeletal function and/or mediate movement of the cell or the organelles within the cell.Myosin Heavy Chains: The larger subunits of MYOSINS. The heavy chains have a molecular weight of about 230 kDa and each heavy chain is usually associated with a dissimilar pair of MYOSIN LIGHT CHAINS. The heavy chains possess actin-binding and ATPase activity.Myosin Subfragments: Parts of the myosin molecule resulting from cleavage by proteolytic enzymes (PAPAIN; TRYPSIN; or CHYMOTRYPSIN) at well-localized regions. Study of these isolated fragments helps to delineate the functional roles of different parts of myosin. Two of the most common subfragments are myosin S-1 and myosin S-2. S-1 contains the heads of the heavy chains plus the light chains and S-2 contains part of the double-stranded, alpha-helical, heavy chain tail (myosin rod).Phalloidine: Very toxic polypeptide isolated mainly from AMANITA phalloides (Agaricaceae) or death cup; causes fatal liver, kidney and CNS damage in mushroom poisoning; used in the study of liver damage.Myosin Type II: The subfamily of myosin proteins that are commonly found in muscle fibers. Myosin II is also involved a diverse array of cellular functions including cell division, transport within the GOLGI APPARATUS, and maintaining MICROVILLI structure.Gelsolin: A 90-kDa protein produced by macrophages that severs ACTIN filaments and forms a cap on the newly exposed filament end. Gelsolin is activated by CALCIUM ions and participates in the assembly and disassembly of actin, thereby increasing the motility of some CELLS.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.Actin Capping Proteins: Actin capping proteins are cytoskeletal proteins that bind to the ends of ACTIN FILAMENTS to regulate actin polymerization.Tropomyosin: A protein found in the thin filaments of muscle fibers. It inhibits contraction of the muscle unless its position is modified by TROPONIN.Myosin Type V: A subclass of myosin involved in organelle transport and membrane targeting. It is abundantly found in nervous tissue and neurosecretory cells. The heavy chains of myosin V contain unusually long neck domains that are believed to aid in translocating molecules over large distances.Myosin Light Chains: The smaller subunits of MYOSINS that bind near the head groups of MYOSIN HEAVY CHAINS. The myosin light chains have a molecular weight of about 20 KDa and there are usually one essential and one regulatory pair of light chains associated with each heavy chain. Many myosin light chains that bind calcium are considered "calmodulin-like" proteins.Cytochalasin D: A fungal metabolite that blocks cytoplasmic cleavage by blocking formation of contractile microfilament structures resulting in multinucleated cell formation, reversible inhibition of cell movement, and the induction of cellular extrusion. Additional reported effects include the inhibition of actin polymerization, DNA synthesis, sperm motility, glucose transport, thyroid secretion, and growth hormone release.Cytoskeletal Proteins: Major constituent of the cytoskeleton found in the cytoplasm of eukaryotic cells. They form a flexible framework for the cell, provide attachment points for organelles and formed bodies, and make communication between parts of the cell possible.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.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.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.Actomyosin: A protein complex of actin and MYOSINS occurring in muscle. It is the essential contractile substance of muscle.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.Chickens: Common name for the species Gallus gallus, the domestic fowl, in the family Phasianidae, order GALLIFORMES. It is descended from the red jungle fowl of SOUTHEAST ASIA.Destrin: A member of the actin depolymerizing factors. Its depolymerizing activity is independent of HYDROGEN-ION CONCENTRATION.Actinin: A protein factor that regulates the length of R-actin. It is chemically similar, but immunochemically distinguishable from actin.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.Muscles: Contractile tissue that produces movement in animals.Actin-Related Protein 2-3 Complex: A complex of seven proteins including ARP2 PROTEIN and ARP3 PROTEIN that plays an essential role in maintenance and assembly of the CYTOSKELETON. Arp2-3 complex binds WASP PROTEIN and existing ACTIN FILAMENTS, and it nucleates the formation of new branch point filaments.Microscopy, Electron, Scanning: Microscopy in which the object is examined directly by an electron beam scanning the specimen point-by-point. The image is constructed by detecting the products of specimen interactions that are projected above the plane of the sample, such as backscattered electrons. Although SCANNING TRANSMISSION ELECTRON MICROSCOPY also scans the specimen point by point with the electron beam, the image is constructed by detecting the electrons, or their interaction products that are transmitted through the sample plane, so that is a form of TRANSMISSION ELECTRON MICROSCOPY.Microtubules: Slender, cylindrical filaments found in the cytoskeleton of plant and animal cells. They are composed of the protein TUBULIN and are influenced by TUBULIN MODULATORS.Myosin Type I: A subclass of myosins found generally associated with actin-rich membrane structures such as filopodia. Members of the myosin type I family are ubiquitously expressed in eukaryotes. The heavy chains of myosin type I lack coiled-coil forming sequences in their tails and therefore do not dimerize.Thiazolidines: Reduced (protonated) form of THIAZOLES. They can be oxidized to THIAZOLIDINEDIONES.Desmosomes: A type of junction that attaches one cell to its neighbor. One of a number of differentiated regions which occur, for example, where the cytoplasmic membranes of adjacent epithelial cells are closely apposed. It consists of a circular region of each membrane together with associated intracellular microfilaments and an intercellular material which may include, for example, mucopolysaccharides. (From Glick, Glossary of Biochemistry and Molecular Biology, 1990; Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)Keratin-8: A type II keratin found associated with KERATIN-18 in simple, or predominately single layered, internal epithelia.Myofibrils: The long cylindrical contractile organelles of STRIATED MUSCLE cells composed of ACTIN FILAMENTS; MYOSIN filaments; and other proteins organized in arrays of repeating units called SARCOMERES .Kinetics: The rate dynamics in chemical or physical systems.Peripherins: Type III intermediate filament proteins expressed mainly in neurons of the peripheral and CENTRAL NERVOUS SYSTEMS. Peripherins are implicated in neurite elongation during development and axonal regeneration after injury.Pseudopodia: A dynamic actin-rich extension of the surface of an animal cell used for locomotion or prehension of food.CapZ Actin Capping Protein: An actin capping protein that binds to the barbed-ends of ACTIN filaments. It is a heterodimer consisting of an alpha and a beta subunit. It regulates actin assembly by stabilizing actin oligomers for elongation. In SKELETAL MUSCLE, CapZ is localized to the Z-disk.Actin-Related Protein 2: A PROFILIN binding domain protein that is part of the Arp2-3 complex. It is related in sequence and structure to ACTIN and binds ATP.Neurofilament Proteins: Type III intermediate filament proteins that assemble into neurofilaments, the major cytoskeletal element in nerve axons and dendrites. They consist of three distinct polypeptides, the neurofilament triplet. Types I, II, and IV intermediate filament proteins form other cytoskeletal elements such as keratins and lamins. It appears that the metabolism of neurofilaments is disturbed in Alzheimer's disease, as indicated by the presence of neurofilament epitopes in the neurofibrillary tangles, as well as by the severe reduction of the expression of the gene for the light neurofilament subunit of the neurofilament triplet in brains of Alzheimer's patients. (Can J Neurol Sci 1990 Aug;17(3):302)Muscle Proteins: The protein constituents of muscle, the major ones being ACTINS and MYOSINS. More than a dozen accessory proteins exist including TROPONIN; TROPOMYOSIN; and DYSTROPHIN.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.Nonmuscle Myosin Type IIA: A nonmuscle isoform of myosin type II found predominantly in platelets, lymphocytes, neutrophils and brush border enterocytes.Nestin: A type VI intermediate filament protein expressed mostly in nerve cells where it is associated with the survival, renewal and mitogen-stimulated proliferation of neural progenitor cells.Tropomodulin: An actin capping protein that binds to the pointed-end of ACTIN. It functions in the presence of TROPOMYOSIN to inhibit microfilament elongation.Actin-Related Protein 3: A component of the Arp2-3 complex that is related in sequence and structure to ACTIN and that binds ATP. It is expressed at higher levels than ARP2 PROTEIN and does not contain a PROFILIN binding domain.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.Plectin: A cytoskeletal linker protein with a molecular weight of greater than 500 kDa. It binds INTERMEDIATE FILAMENTS; MICROTUBULES; and ACTIN CYTOSKELETON and plays a central role in the organization and stability of the CYTOSKELETON. Plectin is phosphorylated by CALMODULIN KINASE; PROTEIN KINASE A; and PROTEIN KINASE C.Cell Line: Established cell cultures that have the potential to propagate indefinitely.Molecular Motor Proteins: Proteins that are involved in or cause CELL MOVEMENT such as the rotary structures (flagellar motor) or the structures whose movement is directed along cytoskeletal filaments (MYOSIN; KINESIN; and DYNEIN motor families).Sarcomeres: The repeating contractile units of the MYOFIBRIL, delimited by Z bands along its length.Glial Fibrillary Acidic Protein: An intermediate filament protein found only in glial cells or cells of glial origin. MW 51,000.Nonmuscle Myosin Type IIB: A nonmuscle isoform of myosin type II found predominantly in neuronal tissue.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.GizzardBiopolymers: Polymers synthesized by living organisms. They play a role in the formation of macromolecular structures and are synthesized via the covalent linkage of biological molecules, especially AMINO ACIDS; NUCLEOTIDES; and CARBOHYDRATES.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.Phosphorylation: The introduction of a phosphoryl group into a compound through the formation of an ester bond between the compound and a phosphorus moiety.Polymers: Compounds formed by the joining of smaller, usually repeating, units linked by covalent bonds. These compounds often form large macromolecules (e.g., BIOPOLYMERS; PLASTICS).Desmoplakins: Desmoplakins are cytoskeletal linker proteins that anchor INTERMEDIATE FILAMENTS to the PLASMA MEMBRANE at DESMOSOMES.Electrophoresis, Polyacrylamide Gel: Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.Epithelium: One or more layers of EPITHELIAL CELLS, supported by the basal lamina, which covers the inner or outer surfaces of the body.Bicyclo Compounds, Heterocyclic: A class of saturated compounds consisting of two rings only, having two or more atoms in common, containing at least one hetero atom, and that take the name of an open chain hydrocarbon containing the same total number of atoms. (From Riguady et al., Nomenclature of Organic Chemistry, 1979, p31)Cytochalasins: 11- to 14-membered macrocyclic lactones with a fused isoindolone. Members with INDOLES attached at the C10 position are called chaetoglobosins. They are produced by various fungi. Some members interact with ACTIN and inhibit CYTOKINESIS.Lamins: Nuclear matrix proteins that are structural components of the NUCLEAR LAMINA. They are found in most multicellular organisms.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.Cardiac Myosins: Myosin type II isoforms found in cardiac muscle.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.Carrier Proteins: Transport proteins that carry specific substances in the blood or across cell membranes.Contractile Proteins: Proteins which participate in contractile processes. They include MUSCLE PROTEINS as well as those found in other cells and tissues. In the latter, these proteins participate in localized contractile events in the cytoplasm, in motile activity, and in cell aggregation phenomena.Molecular Weight: The sum of the weight of all the atoms in a molecule.Profilins: A family of low molecular weight proteins that bind ACTIN and control actin polymerization. They are found in eukaryotes and are ubiquitously expressed.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)Cell Movement: The movement of cells from one location to another. Distinguish from CYTOKINESIS which is the process of dividing the CYTOPLASM of a cell.Viscosity: The resistance that a gaseous or liquid system offers to flow when it is subjected to shear stress. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)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).Connectin: A giant elastic protein of molecular mass ranging from 2,993 kDa (cardiac), 3,300 kDa (psoas), to 3,700 kDa (soleus) having a kinase domain. The amino- terminal is involved in a Z line binding, and the carboxy-terminal region is bound to the myosin filament with an overlap between the counter-connectin filaments at the M line.Muscle, Smooth: Unstriated and unstriped muscle, one of the muscles of the internal organs, blood vessels, hair follicles, etc. Contractile elements are elongated, usually spindle-shaped cells with centrally located nuclei. Smooth muscle fibers are bound together into sheets or bundles by reticular fibers and frequently elastic nets are also abundant. (From Stedman, 25th ed)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.Muscle, Skeletal: A subtype of striated muscle, attached by TENDONS to the SKELETON. Skeletal muscles are innervated and their movement can be consciously controlled. They are also called voluntary muscles.Models, Molecular: Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.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.Dipodomys: A genus of the family Heteromyidae which contains 22 species. Their physiology is adapted for the conservation of water, and they seldom drink water. They are found in arid or desert habitats and travel by hopping on their hind limbs.Cofilin 1: Cofilin 1 is a member of the cofilin family of proteins that is expressed in non-muscle CELLS. It has ACTIN depolymerization activity that is dependent on HYDROGEN-ION CONCENTRATION.Nerve Tissue ProteinsFreeze Etching: A replica technique in which cells are frozen to a very low temperature and cracked with a knife blade to expose the interior surfaces of the cells or cell membranes. The cracked cell surfaces are then freeze-dried to expose their constituents. The surfaces are now ready for shadowing to be viewed using an electron microscope. This method differs from freeze-fracturing in that no cryoprotectant is used and, thus, allows for the sublimation of water during the freeze-drying process to etch the surfaces.Vinculin: A cytoskeletal protein associated with cell-cell and cell-matrix interactions. The amino acid sequence of human vinculin has been determined. The protein consists of 1066 amino acid residues and its gene has been assigned to chromosome 10.Calmodulin-Binding Proteins: Proteins which bind calmodulin. They are found in many tissues and have a variety of functions including F-actin cross-linking properties, inhibition of cyclic nucleotide phosphodiesterase and calcium and magnesium ATPases.Ca(2+) Mg(2+)-ATPaseBase Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Cell Membrane: The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.Myosin-Light-Chain Kinase: An enzyme that phosphorylates myosin light chains in the presence of ATP to yield myosin-light chain phosphate and ADP, and requires calcium and CALMODULIN. The 20-kDa light chain is phosphorylated more rapidly than any other acceptor, but light chains from other myosins and myosin itself can act as acceptors. The enzyme plays a central role in the regulation of smooth muscle contraction.Muscle Contraction: A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments.Keratin-18: A type I keratin found associated with KERATIN-8 in simple, or predominately single layered, internal epithelia.Polymerization: Chemical reaction in which monomeric components are combined to form POLYMERS (e.g., POLYMETHYLMETHACRYLATE).Immunohistochemistry: Histochemical localization of immunoreactive substances using labeled antibodies as reagents.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.Adenosine Triphosphatases: A group of enzymes which catalyze the hydrolysis of ATP. The hydrolysis reaction is usually coupled with another function such as transporting Ca(2+) across a membrane. These enzymes may be dependent on Ca(2+), Mg(2+), anions, H+, or DNA.Demecolcine: An alkaloid isolated from Colchicum autumnale L. and used as an antineoplastic.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.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.Dictyostelium: A genus of protozoa, formerly also considered a fungus. Its natural habitat is decaying forest leaves, where it feeds on bacteria. D. discoideum is the best-known species and is widely used in biomedical research.Protein Isoforms: Different forms of a protein that may be produced from different GENES, or from the same gene by ALTERNATIVE SPLICING.Lamin Type B: A subclass of ubiquitously-expressed lamins having an acidic isoelectric point. They are found to remain bound to nuclear membranes during mitosis.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.Intercellular Junctions: Direct contact of a cell with a neighboring cell. Most such junctions are too small to be resolved by light microscopy, but they can be visualized by conventional or freeze-fracture electron microscopy, both of which show that the interacting CELL MEMBRANE and often the underlying CYTOPLASM and the intervening EXTRACELLULAR SPACE are highly specialized in these regions. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p792)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.Depsipeptides: Compounds consisting of chains of AMINO ACIDS alternating with CARBOXYLIC ACIDS via ester and amide linkages. They are commonly cyclized.Epidermolysis Bullosa Simplex: A form of epidermolysis bullosa characterized by serous bullae that heal without scarring. Mutations in the genes that encode KERATIN-5 and KERATIN-14 have been associated with several subtypes of epidermolysis bullosa simplex.Fibroblasts: Connective tissue cells which secrete an extracellular matrix rich in collagen and other macromolecules.Muscle, Striated: One of two types of muscle in the body, characterized by the array of bands observed under microscope. Striated muscles can be divided into two subtypes: the CARDIAC MUSCLE and the SKELETAL MUSCLE.Acanthamoeba: A genus of free-living soil amoebae that produces no flagellate stage. Its organisms are pathogens for several infections in humans and have been found in the eye, bone, brain, and respiratory tract.Cytochalasin B: A cytotoxic member of the CYTOCHALASINS.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.Plakins: A family of related proteins that associate with cytoskeletal elements and junctional complexes at INTERCELLULAR JUNCTIONS. Plakins share a common plakin domain or a plakin repeat domain.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Peptide Fragments: Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.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.Myosin Type III: A subclass of myosins originally found in the photoreceptor of DROSOPHILA. The heavy chains can occur as two alternatively spliced isoforms of 132 and 174 KDa. The amino terminal of myosin type III is highly unusual in that it contains a protein kinase domain which may be an important component of the visual process.Troponin: One of the minor protein components of skeletal muscle. Its function is to serve as the calcium-binding component in the troponin-tropomyosin B-actin-myosin complex by conferring calcium sensitivity to the cross-linked actin and myosin filaments.Tubulin: A microtubule subunit protein found in large quantities in mammalian brain. It has also been isolated from SPERM FLAGELLUM; CILIA; and other sources. Structurally, the protein is a dimer with a molecular weight of approximately 120,000 and a sedimentation coefficient of 5.8S. It binds to COLCHICINE; VINCRISTINE; and VINBLASTINE.Heterocyclic Compounds with 4 or More Rings: A class of organic compounds containing four or more ring structures, one of which is made up of more than one kind of atom, usually carbon plus another atom. The heterocycle may be either aromatic or nonaromatic.Calcium-Binding Proteins: Proteins to which calcium ions are bound. They can act as transport proteins, regulator proteins, or activator proteins. They typically contain EF HAND MOTIFS.Recombinant Proteins: Proteins prepared by recombinant DNA technology.Adenosine Diphosphate: Adenosine 5'-(trihydrogen diphosphate). An adenine nucleotide containing two phosphate groups esterified to the sugar moiety at the 5'-position.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.Lamin Type A: A subclass of developmentally regulated lamins having a neutral isoelectric point. They are found to disassociate from nuclear membranes during mitosis.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.Rhodamines: A family of 3,6-di(substituted-amino)-9-benzoate derivatives of xanthene that are used as dyes and as indicators for various metals; also used as fluorescent tracers in histochemistry.Nocodazole: Nocodazole is an antineoplastic agent which exerts its effect by depolymerizing microtubules.Stress, Mechanical: A purely physical condition which exists within any material because of strain or deformation by external forces or by non-uniform thermal expansion; expressed quantitatively in units of force per unit area.Turkeys: Large woodland game BIRDS in the subfamily Meleagridinae, family Phasianidae, order GALLIFORMES. Formerly they were considered a distinct family, Melegrididae.Cytoplasmic Streaming: The movement of CYTOPLASM within a CELL. It serves as an internal transport system for moving essential substances throughout the cell, and in single-celled organisms, such as the AMOEBA, it is responsible for the movement (CELL MOVEMENT) of the entire cell.Elasticity: Resistance and recovery from distortion of shape.Antibodies, Monoclonal: Antibodies produced by a single clone of cells.Filamins: A family of crosslinking filament proteins encoded by distinct FLN genes. Filamins are involved in cell adhesion, spreading, and migration, acting as scaffolds for over 90 binding partners including channels, receptors, intracellular signaling molecules and transcription factors. Due to the range of molecular interactions, mutations in FLN genes result in anomalies with moderate to lethal consequences.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.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.PhosphoproteinsAmoeba: A genus of ameboid protozoa. Characteristics include a vesicular nucleus and the formation of several lodopodia, one of which is dominant at a given time. Reproduction occurs asexually by binary fission.Macropodidae: A family of herbivorous leaping MAMMALS of Australia, New Guinea, and adjacent islands. Members include kangaroos, wallabies, quokkas, and wallaroos.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.Inclusion Bodies: A generic term for any circumscribed mass of foreign (e.g., lead or viruses) or metabolically inactive materials (e.g., ceroid or MALLORY BODIES), within the cytoplasm or nucleus of a cell. Inclusion bodies are in cells infected with certain filtrable viruses, observed especially in nerve, epithelial, or endothelial cells. (Stedman, 25th ed)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.Wiskott-Aldrich Syndrome Protein, Neuronal: A member of the Wiskott-Aldrich syndrome protein family that is found at high levels in NERVE CELLS. It interacts with GRB2 ADAPTOR PROTEIN and with CDC42 PROTEIN.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.Cell Nucleus: Within a eukaryotic cell, a membrane-limited body which contains chromosomes and one or more nucleoli (CELL NUCLEOLUS). The nuclear membrane consists of a double unit-type membrane which is perforated by a number of pores; the outermost membrane is continuous with the ENDOPLASMIC RETICULUM. A cell may contain more than one nucleus. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)Cell Adhesion: Adherence of cells to surfaces or to other cells.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.Smooth Muscle Myosins: Myosin type II isoforms found in smooth muscle.Chick Embryo: The developmental entity of a fertilized chicken egg (ZYGOTE). The developmental process begins about 24 h before the egg is laid at the BLASTODISC, a small whitish spot on the surface of the EGG YOLK. After 21 days of incubation, the embryo is fully developed before hatching.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.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.Biophysics: The study of PHYSICAL PHENOMENA and PHYSICAL PROCESSES as applied to living things.Colchicine: A major alkaloid from Colchicum autumnale L. and found also in other Colchicum species. Its primary therapeutic use is in the treatment of gout, but it has been used also in the therapy of familial Mediterranean fever (PERIODIC DISEASE).Wiskott-Aldrich Syndrome Protein: WASP protein is mutated in WISKOTT-ALDRICH SYNDROME and is expressed primarily in hematopoietic cells. It is the founding member of the WASP protein family and interacts with CDC42 PROTEIN to help regulate ACTIN polymerization.Biophysical Phenomena: The physical characteristics and processes of biological systems.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.Muscle Fibers, Skeletal: Large, multinucleate single cells, either cylindrical or prismatic in shape, that form the basic unit of SKELETAL MUSCLE. They consist of MYOFIBRILS enclosed within and attached to the SARCOLEMMA. They are derived from the fusion of skeletal myoblasts (MYOBLASTS, SKELETAL) into a syncytium, followed by differentiation.Cell Differentiation: Progressive restriction of the developmental potential and increasing specialization of function that leads to the formation of specialized cells, tissues, and organs.Horseshoe Crabs: An arthropod subclass (Xiphosura) comprising the North American (Limulus) and Asiatic (Tachypleus) genera of horseshoe crabs.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.Phenotype: The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.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.Swine: Any of various animals that constitute the family Suidae and comprise stout-bodied, short-legged omnivorous mammals with thick skin, usually covered with coarse bristles, a rather long mobile snout, and small tail. Included are the genera Babyrousa, Phacochoerus (wart hogs), and Sus, the latter containing the domestic pig (see SUS SCROFA).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.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.Cell Compartmentation: A partitioning within cells due to the selectively permeable membranes which enclose each of the separate parts, e.g., mitochondria, lysosomes, etc.Biomechanical Phenomena: The properties, processes, and behavior of biological systems under the action of mechanical forces.rho-Associated Kinases: A group of intracellular-signaling serine threonine kinases that bind to RHO GTP-BINDING PROTEINS. They were originally found to mediate the effects of rhoA GTP-BINDING PROTEIN on the formation of STRESS FIBERS and FOCAL ADHESIONS. Rho-associated kinases have specificity for a variety of substrates including MYOSIN-LIGHT-CHAIN PHOSPHATASE and LIM KINASES.Protein Multimerization: The assembly of the QUATERNARY PROTEIN STRUCTURE of multimeric proteins (MULTIPROTEIN COMPLEXES) from their composite PROTEIN SUBUNITS.Microinjections: The injection of very small amounts of fluid, often with the aid of a microscope and microsyringes.rho GTP-Binding Proteins: A large family of MONOMERIC GTP-BINDING PROTEINS that are involved in regulation of actin organization, gene expression and cell cycle progression. This enzyme was formerly listed as EC 3.6.1.47.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.Histocytochemistry: Study of intracellular distribution of chemicals, reaction sites, enzymes, etc., by means of staining reactions, radioactive isotope uptake, selective metal distribution in electron microscopy, or other methods.Calmodulin: A heat-stable, low-molecular-weight activator protein found mainly in the brain and heart. The binding of calcium ions to this protein allows this protein to bind to cyclic nucleotide phosphodiesterases and to adenyl cyclase with subsequent activation. Thereby this protein modulates cyclic AMP and cyclic GMP levels.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.Cricetinae: A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.Cell Shape: The quality of surface form or outline of CELLS.Desmogleins: A group of desmosomal cadherins with cytoplasmic tails that resemble those of classical CADHERINS.Movement: The act, process, or result of passing from one place or position to another. It differs from LOCOMOTION in that locomotion is restricted to the passing of the whole body from one place to another, while movement encompasses both locomotion but also a change of the position of the whole body or any of its parts. Movement may be used with reference to humans, vertebrate and invertebrate animals, and microorganisms. Differentiate also from MOTOR ACTIVITY, movement associated with behavior.Keratin-17: A type I keratin found associated with KERATIN-6 in rapidly proliferating squamous epithelial tissue. Mutations in the gene for keratin-17 have been associated with PACHYONYCHIA CONGENITA, TYPE 2.Myocardium: The muscle tissue of the HEART. It is composed of striated, involuntary muscle cells (MYOCYTES, CARDIAC) connected to form the contractile pump to generate blood flow.Epidermis: The external, nonvascular layer of the skin. It is made up, from within outward, of five layers of EPITHELIUM: (1) basal layer (stratum basale epidermidis); (2) spinous layer (stratum spinosum epidermidis); (3) granular layer (stratum granulosum epidermidis); (4) clear layer (stratum lucidum epidermidis); and (5) horny layer (stratum corneum epidermidis).Cell Size: The quantity of volume or surface area of CELLS.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.Staining and Labeling: The marking of biological material with a dye or other reagent for the purpose of identifying and quantitating components of tissues, cells or their extracts.Cytokinesis: The process by which the CYTOPLASM of a cell is divided.DNA, 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.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)Spectrometry, Fluorescence: Measurement of the intensity and quality of fluorescence.
Hirokawa N, Tilney LG, Fujiwara K, Heuser JE (1982). "Organization of actin, myosin, and intermediate filaments in the brush ... When contracted, the terminal web causes a decrease in diameter of the apex of the cell, causing the microvilli, which are ... It is composed primarily of actin filaments stabilized by spectrin, which also anchors the terminal web to the apical cell ... The presence of myosin II and tropomyosin helps to explain the contractile ability of the terminal web. ...
The two primary cytoskeletal components of costameres are desmin intermediate filaments and gamma-actin microfilaments. It has ... "The correlation between the synthesis of skeletal muscle actin, myosin heavy chain, and myosin light chain and the accumulation ... Bretscher A, Weber K (Jul 1980). "Villin is a major protein of the microvillus cytoskeleton which binds both G and F actin in a ... Craig SW, Pardo JV (1983). "Gamma actin, spectrin, and intermediate filament proteins colocalize with vinculin at costameres, ...
... , also known as KRT5, K5, or CK5, is a protein that is encoded in humans by the KRT5 gene. It dimerizes with keratin 14 and forms the intermediate filaments (IF) that make up the cytoskeleton of basal epithelial cells. This protein is involved in several diseases including epidermolysis bullosa simplex and breast and lung cancers. Keratin 5, like other members of the keratin family, is an intermediate filament protein. These polypeptides are characterized by a 310 residue central rod domain that consists of four alpha helix segments (helix 1A, 1B, 2A, and 2B) connected by three short linker regions (L1, L1-2, and L2). The ends of the central rod domain, which are called the helix initiation motif (HIM) and the helix termination motif (HTM), are highly conserved. They are especially important for helix stabilization, heterodimer formation, and filament formation. Lying on either side of the central rod are variable, non-helical head and ...
neuroaxonal damage is the pathological substrate of permanent disability in various neurological disorders. ... Here, we review what is known about the structure and function of neurofilaments, discuss analytical aspects and knowledge of age-dependent normal ranges of neurofilaments and provide a comprehensive overview of studies on neurofilament light chain as a marker of axonal injury in different neurological disorders, including multiple sclerosis, neurodegenerative dementia, stroke, traumatic brain injury, amyotrophic lateral sclerosis and Parkinson disease ...
Recent research has focused on changing the mixture of keratins produced in the skin. There are 54 known keratin genes-of which 28 belong to the type I intermediate filament genes and 26 to type II-which work as heterodimers. Many of these genes share substantial structural and functional similarity, but they are specialized to cell type and/or conditions under which they are normally produced. If the balance of production could be shifted away from the mutated, dysfunctional keratin gene toward an intact keratin gene, symptoms could be reduced. For example, sulforaphane, a compound found in broccoli, was found to reduce blistering in a mouse model to the point where affected pups could not be identified visually, when injected into pregnant mice (5 µmol/day = 0.9 mg) and applied topically to newborns (1 µmol/day = 0.2 mg in jojoba oil).[13] As of 2008 clinical research at the University of Minnesota has included a bone marrow transplant to a 2-year-old child who is one of 2 brothers with ...
... (GFAP) is a protein that is encoded by the GFAP gene in humans. Glial fibrillary acidic protein is an intermediate filament (IF) protein that is expressed by numerous cell types of the central nervous system (CNS) including astrocytes and ependymal cells. GFAP has also been found to be expressed in glomeruli and peritubular fibroblasts taken from rat kidneys Leydig cells of the testis in both hamsters and humans, human keratinocytes, human osteocytes and chondrocytes and stellate cells of the pancreas and liver in rats. First described in 1971, GFAP is a type III IF protein that maps, in humans, to 17q21. It is closely related to its non-epithelial family members, vimentin, desmin, and peripherin, which are all involved in the structure and function of the cell's cytoskeleton. GFAP is thought to help to maintain astrocyte mechanical strength, as well as the shape of cells but its exact function remains poorly understood, despite the number of studies using it as a ...
Keratin, type II cytoskeletal 7 also known as cytokeratin-7 (CK-7) or keratin-7 (K7) or sarcolectin (SCL) is a protein that in humans is encoded by the KRT7 gene. Keratin 7 is a type II keratin. It is specifically expressed in the simple epithelia lining the cavities of the internal organs and in the gland ducts and blood vessels. Keratin-7 is a member of the keratin gene family. The type II cytokeratins consist of basic or neutral proteins which are arranged in pairs of heterotypic keratin chains coexpressed during differentiation of simple and stratified epithelial tissues. This type II cytokeratin is specifically expressed in the simple epithelia lining the cavities of the internal organs and in the gland ducts and blood vessels. The genes encoding the type II cytokeratins are clustered in a region of chromosome 12q12-q13. Alternative splicing may result in several transcript variants; however, not all variants have been fully described. Keratin-7 is found in simple glandular epithelia, and ...
... (/ˈkɛrətɪn/) is one of a family of fibrous structural proteins. It is the key structural material making up hair, horns, claws, hooves, and the outer layer of human skin. Keratin is also the protein that protects epithelial cells from damage or stress. Keratin is extremely insoluble in water and organic solvents. Keratin monomers assemble into bundles to form intermediate filaments, which are tough and form strong unmineralized epidermal appendages found in reptiles, birds, amphibians, and mammals. The only other biological matter known to approximate the toughness of keratinized tissue is chitin. Keratin derives from Greek κερατίνη from Greek keras (κέρας) (genitive keratos, κέρατος) meaning "horn" originating from the Proto-Indo-European *ḱer- of the same meaning. It is composed of "horn like", i.e., kerato, to which the chemical suffix -in is appended. The Greek keras (or keros) is used in many animal names, e.g. Rhinoceros, meaning "nose with a ...
核纖層是真核生物细胞核中附于内核膜(英语:inner nuclear membrane)内侧的网络片层结构。其核纤层蛋白家族在进化中高度保守。在有絲分裂过程中,核纤层蛋白磷酸化,核纖層解聚(这一过程是可逆的)。Lamin蛋白質被認為與細胞核的穩定性、染色質的結構與基因的表達有關. Vertebrate lamins consist of two types, A and B. Through alternate splicing, this gene encodes three type A lamin isoforms.[4] Early in mitosis, MPF phosphorylates specific serine residues in all three nuclear lamins, causing depolymerization of the lamin intermediate filaments. The phosphorylated lamin B dimers remain associated with the nuclear membrane via their isoprenyl anchor. Lamin A is targeted to the nuclear membrane by an isoprenyl group but it is cleaved shortly after arriving at the membrane. It stays associated with the membrane through protein-protein interactions of itself and other membrane associated proteins, such as ...
Perez-Olle R, Lopez-Toledano MA, Liem RK (2004). "The G336S variant in the human neurofilament-M gene does not affect its assembly or distribution: importance of the functional analysis of neurofilament variants". J. Neuropathol. Exp. Neurol. 63 (7): 759-74. PMID 15290901 ...
Myosin-1, also known as 'striated muscle myosin heavy chain 1', is a protein that in humans is encoded by the MYH1 gene. This gene is most highly expressed in fast type IIX/D muscle fibres of vertebrates and encodes a protein found uniquely in striated muscle; it is a class II myosin with a long coiled coil tail that dimerizes and should not be confused with 'Myosin 1' encoded by the MYO1 family of genes (MYO1A-MYO1H). Class I MYO1 genes function in many cell types throughout biology and are single-headed membrane-binding myosins that lack a long coiled coil tail. Myosin is a major contractile protein that converts chemical energy into mechanical energy through the hydrolysis of ATP. Class II Myosins are hexameric proteins composed of a pair of myosin heavy chains (MYH) and two pairs of nonidentical light chains. Myosin heavy chains are encoded by a ...
Myosin regulatory light polypeptide 9 is a protein that in humans is encoded by the MYL9 gene. Myosin, a structural component of muscle, consists of two heavy chains and four light chains. The protein encoded by this gene is a myosin light chain that may regulate muscle contraction by modulating the ATPase activity of myosin heads. The encoded protein binds calcium and is activated by myosin light chain kinase. Two transcript variants encoding different isoforms have been found for this gene. GRCh38: Ensembl release 89: ENSG00000101335 - Ensembl, May 2017 GRCm38: Ensembl release 89: ENSMUSG00000067818 - Ensembl, May 2017 "Human PubMed Reference:". "Mouse PubMed Reference:". Kumar CC, Mohan SR, Zavodny PJ, Narula SK, Leibowitz PJ (May 1989). "Characterization and differential expression of human vascular smooth muscle myosin light chain 2 isoform in nonmuscle cells". Biochemistry. 28 (9): 4027-35. ...
... is a gene encoding a myosin heavy chain beta (MHC-β) isoform (slow twitch) expressed primarily in the heart, but also in skeletal muscles (type I fibers). This isoform is distinct from the fast isoform of cardiac myosin heavy chain, MYH6, referred to as MHC-α. MHC-β is the major protein comprising the thick filament in cardiac muscle and plays a major role in cardiac muscle contraction. MHC-β is a 223 kDa protein composed of 1935 amino acids. MHC-β is a hexameric, asymmetric motor forming the bulk of the thick filament in cardiac muscle. MHC-β is composed of N-terminal globular heads (20 nm) that project laterally, and alpha helical tails (130 nm) that dimerize and multimerize into a coiled-coil motif to form the light meromyosin (LMM), thick filament rod. The 9 nm alpha-helical neck region of each MHC-β head non-covalently binds two light chains, essential light chain (MYL3) and regulatory light chain (MYL2). Approximately 300 myosin ...
... inhibits myosin ATPase activity and this way acto-myosin based motility. It binds halfway between the nucleotide binding pocket and the actin binding cleft of myosin, predominantly in an actin detached conformation.[10] This type of inhibition relaxes the acto-myosin myofilaments and leads to several biological effects. Blebbistatin inhibits the formation of blebs in melanoma cell culture,[11] hence its name. At a cellular level, blebbistatin also inhibits cytokinesis [11] and may also disrupt mitotic spindle formation.[12] Migration of cells can be either enhanced or inhibited depending on other conditions.[13] In neurons, blebbistatin was found to promote neurite outgrowth.[14] At the organ level blebbistatin stops the contraction of skeletal muscle [15] or heart muscle.[16] Blebbistatin has also been found to stabilize the super relaxed state in the ...
ADP cycling supplies the energy needed to do work in a biological system, the thermodynamic process of transferring energy from one source to another. There are two types of energy: potential energy and kinetic energy. Potential energy can be thought of as stored energy, or usable energy that is available to do work. Kinetic energy is the energy of an object as a result of its motion. The significance of ATP is in its ability to store potential energy within the phosphate bonds. The energy stored between these bonds can then be transferred to do work. For example, the transfer of energy from ATP to the protein myosin causes a conformational change when connecting to actin during muscle contraction. It takes multiple reactions between myosin and actin to effectively produce one muscle contraction, and, therefore, the availability of large amounts of ATP is required to produce each muscle contraction. For this reason, biological processes have ...
Hirokawa N, Tilney LG, Fujiwara K, Heuser JE (1982). "Organization of actin, myosin, and intermediate filaments in the brush ... When contracted, the terminal web causes a decrease in diameter of the apex of the cell, causing the microvilli, which are ... It is composed primarily of actin filaments stabilized by spectrin, which also anchors the terminal web to the apical cell ... The presence of myosin II and tropomyosin helps to explain the contractile ability of the terminal web. ...
Intermediate filaments = cytokeratin. Other cross-linking proteins:. villin: anchors actin to the tip. myosin I anchors actin ... Long microvilli; 120 um. No villin in the tip. Ezrin anchors actin to cell membrane (no myosin I). Limited in distribution: in ... Actin filaments facilitate attachment to adjacent cells. alpha-actinin - an actin-binding protein also found in the Z-line of ... Cytokeratin intermediate filaments. Continuouslly renewed by mitosis; in layer closest to the basal lamina (stem cells) ...
Organization of actin, myosin, and intermediate filaments in the brush border of intestinal epithelial cells. J Cell Biol. 1982 ... Bretscher A, Weber K. Villin is a major protein of the microvillus cystoskeleton which binds both G and F actin in a calcium- ... The visualization of actin filament polarity in thin sections. Evidence for the uniform polarity of membrane-associated ... Characterization of the 110-kdalton actin-calmodulin-, and membrane-binding protein from microvilli of intestinal epithelial ...
is myosin). 52. Intermediate Filaments*Intermediate in size between actin filaments and microtubules ... Support for microvilli in intestinal cells *Intracellular traffic control *Cytoplasmic streaming *Pseudopods ...
1 Hirokawa, N., Tilney, L.G., Fujiwara, K., and Heuser, J.E. (1982). "Organization of actin, myosin, and intermediate filaments ... is from the bundles of apical filaments at the core of a microvillus as well as from adherens junctions in myosin and in other ... The actin filaments in the terminal web are stabilized by spectrin. They anchor the terminal web to the apical cell membrane. ... and acts as the attachment point for the bundles of apical filaments within microvilli on specialized epithelial cells ...
Muscle actin and myosin required for muscle contraction. *microvilli, stereocilia (do not confuse with cilia MT) ... Intermediate Filaments. *different cell types, different intermediate filaments (all eukaryotes nuclear cytoskeleton the same) ... Actin binding proteins. *myosin motors - walk along actin filament towards the barbed (+) end (exception myosin VI moves ... intermediate filament associated proteins (IFAPs) - coordinate interactions between intermediate filaments and other ...
Intermediate Filament Protein in all cells. Lamin proteins (A, B, C). Intermediate Filament Protein in Neuronal stem cells. ... actin and myosin. Participates in cytoskinesis. Microfilaments. Contractile component of muscles. Microfilaments. ... Microvilli. Components of cell membrane. CHO, Pro, lipids. % Pro, % Lip, % CHO = Cell membrane. 55%, 42%, 3%. ... Intermediate Filament Protein in muscles. Desmin. Intermediate Filament Protein in glial cells, strocytes. Glial Fibrillary ...
... actin filaments form tracts along which chloroplasts circulate. Actin filaments move by interacting with myosin, The myosin ... Actin filaments are thin threads that function in cell division and cell motility. Intermediate filaments are between the size ... Actin filaments in microvilli of intestinal cells act to shorten the cell and thus to pull it out of the intestinal lumen. ... An actin filament consists of two chains of globular actin monomers twisted to form a helix. Actin filaments play a structural ...
The intermediate filaments help maintain the relative positions of organelles and give the cell mechanical strength. The third ... The first are the actin microfilaments, which, with the motor protein myosin, form the muscles of the cytoskeleton (and in ... forming microvilli. They also form undulipodia, which are waving structures with a typical 9+2 structure, found in cilia (short ... The second fibre type are intermediate filaments, composed of spectrin, keratin, vimentin, nuclear lamins and other proteins. ...
Actin may also bind to intrinsic plasma membrane proteins to anchor them in position. • Intermediate filaments. Intermediate ... Membrane specialisations such as microvilli (see Fig. 5.14) also contain a skeleton of actin filaments. Actin plays a central ... The actin and myosin filaments F are essentially unstained in this preparation. THE CELL╇ n╇ Chapter 1: Cell structure and ... The actin filament is then assembled into larger filaments, networks and 3-dimensional structures. Actin filaments are best ...
microvilli. intermediate filaments. ribosomes. Question 15. Question : Unlike cartilage, bone Student Answer: has an outer ... Question : Microscopic analysis of a tissue sample indicates that it contains abundant myosin and actin filaments. This tissue ... intermediate filaments. thick filaments. microsomes. Question 8. Question : Messenger RNA is vital to the cell because Student ... basal bodies thick filaments microfilaments intermediate filaments microtubules Question 36. Question : Most of a cells DNA is ...
In addition, ezrin, a known calpain substrate that links the plasma membrane to axial actin filaments in microvilli, was ... In addition, ezrin, a known calpain substrate that links the plasma membrane to axial actin filaments in microvilli, was ... cleaved in a calpain-dependent manner during EHEC infection and lost from its normal locale within microvilli. Calpain may be a ... cleaved in a calpain-dependent manner during EHEC infection and lost from its normal locale within microvilli. Calpain may be a ...
Actin filaments, vimentin-type intermediate filaments and microtubules all have distinct patterns of distribution that change ... In muscle cells, the association of microfilaments with another protein, myosin, is responsible for muscle contraction. ... like pseudopodia and microvilli), and participate in some cell-to-cell or cell-to-matrix junctions and in the transduction of ... Many intermediate filaments are made of vimentins. Others, in cells of the skin hair and nails, are made of keratin. Some ...
Microvilli Tight junction Actin microfilaments Belt desmosome Desmosome Gap junctions Intermediate filaments Hemidesmosome ... actin) that intertwine to form double-stranded helices. In muscle cells, the filamentous protein myosin binds to actin and ... G-actin), the most abundant cytosolic protein in cells. G-actin monomers noncovalently polymerize into long filaments (F- ... Intermediate filaments are fibrils 10-nm in diameter that comprise a large and heterogeneous family. Members include lamins A, ...
1982). Organization of actin, myosin, and intermediate filaments in the brush border of intestinal epithelial cells. J. Cell ... A microvillus contains a bundle of parallel actin filaments enveloped by plasma membrane. Plus ends of actin filaments point ... Actin staining highlights the filaments of microvilli (large arrowhead), a bulbous structure at the microvillus base (small ... myosin motor proteins, which bind to and travel along actin filaments, control multiple processes in microvilli and stereocilia ...
... system concerning myosin filaments to the forming of rigid structures such as for example those within intestinal microvilli ... Cardiac actin differs from skeletal actin by only four residues, while enteric actin varies at five positions and vascular ... and EDL muscle tissue from hemizygous pets shown an intermediate power era. Thus, while raises in cardiac and vascular smooth- ... Two nonmuscle actins, cytoplasmic - and -actin, are located in nonmuscle cells, and four actins which have become similar one ...
Actin-binding proteins regulate the work performed by myosin II motors on single actin filaments. Cell Motil. Cytoskel 22:274- ... measurement of actin polymerization rate constants by electron microscopy of actin filaments nucleated by isolated microvillus ... In: Intermediate Physics for Medicine and Biology, John Wiley-Sons, New York; 1987.Google Scholar ... Actin Filament Actin Polymerization Pertussis Toxin Actin Monomer Bleb Formation These keywords were added by machine and not ...
Myosin IIIa boosts elongation of stereocilia by transporting espin 1 to the plus ends of actin filaments. Nat Cell Biol 11 443 ... Transient tapering in +/je mice and assembly intermediates. Defects in the appositional growth of the parallel actin bundle ... LoomisPAZhengLSekerkováGChangyaleketBMugnainiE 2003 Espin cross-links cause the elongation of microvillus-type parallel actin ... through the addition of more actin filaments to the parallel actin bundle, and their constituent actin filaments elongate or ...
1.1 Actin Filaments. 1.2 Intermediate Filaments. 1.3 Microtubules. 2 The prokaryotic cytoskeleton. ... They are also important for cytokinesis and, along with myosin, muscular contraction. ... like pseudopods and microvillus), participate in some cell-to-cell or cell-to-matrix junctions and the transduction of signals ... Intermediate Filaments. Main article: intermediate filaments These 8 to 11 nanometers in diameter filaments are the more stable ...
58 The Cytoskeleton: Actin Filament Operation P ATP tail head membrane myosin molecules. ADP + actin filament. Copyright © The ... 59 The Cytoskeleton: Intermediate Filaments Intermediate in size between actin filaments and microtubules Rope-like assembly of ... thin filaments like twisted pearl necklace Dense web just under plasma membrane maintains cell shape Support for microvilli in ... Intermediate filaments c. Microtubules chameleon Chara peacockactin subunit fibrous subunits tubulin dimera. Actin filaments ...
... intermediate filaments and microtubules, forming a network within the cell. Microfilaments made of G-actin found in almost all ... These may be ATP driven as in the case of the contractile proteins; actin and myosin in muscle as well as dynein and tubulin in ... Microvilli Microvilli of intestinal epithelial cells and pseudopodia of macrophages are produced by membrane evagination. This ... cells fuse to form F-actin and exist as a tangled meshwork of 8-9 nm size. Intermediate filaments have approximately 10 nm ...
Actin and myosin.  Intermediate filaments 21 microtubule structure and function o 24 nm diameter. o Heterodimer of alpha and ... o Glycocalyx striated border = glycocalyx + microvilli.  Glycocalyx - carbohydrate chains that vary at the surface of the ... o Thin filament with globular subunits arranged as a double helix.  Polymerization is Ca+ dependent. • Actin Arrangements. o ... can be used to identify cancer based on presence of certain types of intermediate filaments. o 10-12nm. o Keratin - epithelium ...
Evidence is presented that the effects of villin at high calcium are the result of cutting of the actin filaments by villin. It ... The latter inhibition is a consequence of the capping of the barbed filament end by villin as are the inhibition of filament ... Depolymerization was initiated by diluting polymerized actin, labeled with a fluorescent probe on either lysine-374 or cysteine ... sites regulating cutting have a much lower affinity for calcium than the sites regulating capping of the barbed filament ends. ...
muscle contraction with myosin Intermediate Filament (10 nm) - cellular framework - heterogenous group of proteins - marker ... Actin Microfilament G-actin, F-actin - involved in endocytosis, exocytosis, contraction of microvilli - migratory activity - ... Intermediate Filament Microtubule ---- Centriole. Plasma Membrane Composition phospholipid bilayer phosphatidylcholine ( ... microtubules, microfilaments, intermediate filaments. Biological Membrane System Cell Membrane. Nuclear Membrane ---- Nucleus ...
Intermediate Filaments. The intermediate filaments, as the name implies, are sized between the actin filaments and the ... ROCK phosphorylates myosin binding subunit of myosin phophatase (MYPT1) and myosin light chain (MLC) causes a contractile in ... Actin filaments are able to produce reasonably stabilized structures for instance the micro-villi on the brush border cells ... Actin Filaments. Actin Filament- Overview *Actin is spherical protein, approximately 42-kDa established in all eukaryotic cells ...
  • A good example of the latter phenomenon is the report of ezrin specificity for β-actin (3). (cytoskeleton.com)
  • RhoA effector loop mutants which can bind ROCK induce relocalization of ezrin to dorsal actin‐containing cell surface protrusions, as do Net and Dbl. (embopress.org)
  • The solution of the structure of actin greatly benefited from the unexpected observations that actin formed high-affinity complexes with deoxyribonuclease I (DNase I) and profilin, the latter being a protein with now well-understood roles in the regulation of actin biology, while the significance of the former interaction remains unresolved. (springer.com)
  • The high-resolution structure of actin was initially published in 1990. (springer.com)
  • Formation of small protrusions is likely facilitated by Arp3-branched and fimbrin-bundled F-actin networks, which do not depend on Tmod1. (arvojournals.org)
  • Through the use of two independent techniques to remove the effects of gravity, and subsequent TiO 2 sedimentation, it was found that disruption of the microvilli was independent of sedimentation. (springer.com)
  • A/E pathogens typically reside on a pedestal on the surface of the host epithelial cell and ultimately cause severe disruption of the microvilli brush border ( Figure 1A ). (cdc.gov)
  • In animal cells, actin filament provides mechanical support for maintaining or changing the cellular shape. (uvigo.es)
  • Indeed, as further described below, unveiling the complexity of the actin cytoskeleton is an extremely active area of research with far-ranging significance spanning understanding basic cellular mechanisms and pathophysiology. (springer.com)
  • It has been proposed, based on modeling, that the muscle actin genes have evolved from the nonmuscle actin genes by substitutions that lead to conformational changes in the N terminus and the internal dynamics of the actin molecule (19). (antibodyassay.com)
  • While the functional significance of these amino acid exchanges is unknown, members of our laboratory and others have speculated (10) that each muscle actin has evolved to be particularly suited for specialized functional roles in those cells in which they are expressed (see references 23 and 8 for reviews). (antibodyassay.com)
  • Muscle actin has an approximate molecular weight of 43 kDa. (cytoskeleton.com)
  • Rabbit muscle actin is supplied as a white lyophilized powder. (cytoskeleton.com)
  • We show that Myo7A and Cad99C form a molecular complex and that the cytoplasmic tail of Cad99C recruits Myo7A to microvilli. (biologists.org)
  • Human gamma-actin is 41.8 kDa in molecular weight and 375 amino acids in length. (wikipedia.org)
  • There is a complete issue of BBA Molecular Cell Research (volume 1496) published in March 2000 that is full of reviews on molecular motors: various types of myosin, dynein and kinesin. (leeds.ac.uk)
  • Although microvilli show similar external morphology in different cell types, they contain distinct molecular composition and show some differences in their internal structure. (uvigo.es)
  • At sites of bacterial attachment, surface microvilli are effaced, and bacteria intimately adhere to the host cell surface, appearing to partially "sink" into the mammalian cell. (frontiersin.org)