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.Actin Cytoskeleton: Fibers composed of MICROFILAMENT PROTEINS, which are predominately ACTIN. They are the smallest of the cytoskeletal filaments.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.Actin Capping Proteins: Actin capping proteins are cytoskeletal proteins that bind to the ends of ACTIN FILAMENTS to regulate actin polymerization.Cytoskeleton: The network of filaments, tubules, and interconnecting filamentous bridges which give shape, structure, and organization to the cytoplasm.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.Thiazolidines: Reduced (protonated) form of THIAZOLES. They can be oxidized to THIAZOLIDINEDIONES.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.Profilins: A family of low molecular weight proteins that bind ACTIN and control actin polymerization. They are found in eukaryotes and are ubiquitously expressed.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.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.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)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.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.Pseudopodia: A dynamic actin-rich extension of the surface of an animal cell used for locomotion or prehension of food.Tropomyosin: A protein found in the thin filaments of muscle fibers. It inhibits contraction of the muscle unless its position is modified by TROPONIN.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.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.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.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.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.Polymerization: Chemical reaction in which monomeric components are combined to form POLYMERS (e.g., POLYMETHYLMETHACRYLATE).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.Actinin: A protein factor that regulates the length of R-actin. It is chemically similar, but immunochemically distinguishable from actin.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).Depsipeptides: Compounds consisting of chains of AMINO ACIDS alternating with CARBOXYLIC ACIDS via ester and amide linkages. They are commonly cyclized.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.Biopolymers: 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.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.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 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.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.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.cdc42 GTP-Binding Protein: A member of the Rho family of MONOMERIC GTP-BINDING PROTEINS. It is associated with a diverse array of cellular functions including cytoskeletal changes, filopodia formation and transport through the GOLGI APPARATUS. This enzyme was formerly listed as EC 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.Muscles: Contractile tissue that produces movement in animals.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.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.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.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.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.Wiskott-Aldrich Syndrome Protein Family: A family of microfilament proteins whose name derives from the fact that mutations in members of this protein family have been associated with WISKOTT-ALDRICH SYNDROME. They are involved in ACTIN polymerization and contain a polyproline-rich region that binds to PROFILIN, and a verprolin homology domain that binds G-ACTIN.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 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.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.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.Kinetics: The rate dynamics in chemical or physical systems.Carrier Proteins: Transport proteins that carry specific substances in the blood or across cell membranes.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.Cell Surface Extensions: Specialized structures of the cell that extend the cell membrane and project out from the cell surface.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.rhoA GTP-Binding Protein: A RHO GTP-BINDING PROTEIN involved in regulating signal transduction pathways that control assembly of focal adhesions and actin stress fibers. This enzyme was formerly listed as EC Membrane: The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.Cell Line: Established cell cultures that have the potential to propagate indefinitely.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.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.rac1 GTP-Binding Protein: A rac GTP-binding protein involved in regulating actin filaments at the plasma membrane. It controls the development of filopodia and lamellipodia in cells and thereby influences cellular motility and adhesion. It is also involved in activation of NADPH OXIDASE. This enzyme was formerly listed as EC GTP-Binding Proteins: A sub-family of RHO GTP-BINDING PROTEINS that is involved in regulating the organization of cytoskeletal filaments. This enzyme was formerly listed as EC 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.Phosphorylation: The introduction of a phosphoryl group into a compound through the formation of an ester bond between the compound and a phosphorus moiety.Binding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.Fibroblasts: Connective tissue cells which secrete an extracellular matrix rich in collagen and other macromolecules.Cytochalasin B: A cytotoxic member of the CYTOCHALASINS.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.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.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.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.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.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.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.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.Nucleic Acid Synthesis Inhibitors: Compounds that inhibit cell production of DNA or RNA.Tropomodulin: An actin capping protein that binds to the pointed-end of ACTIN. It functions in the presence of TROPOMYOSIN to inhibit microfilament elongation.Focal Adhesions: An anchoring junction of the cell to a non-cellular substrate. It is composed of a specialized area of the plasma membrane where bundles of the ACTIN CYTOSKELETON terminate and attach to the transmembrane linkers, INTEGRINS, which in turn attach through their extracellular domains to EXTRACELLULAR MATRIX PROTEINS.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.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.Cell Shape: The quality of surface form or outline of CELLS.Endocytosis: Cellular uptake of extracellular materials within membrane-limited vacuoles or microvesicles. ENDOSOMES play a central role in endocytosis.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.Phosphatidylinositol 4,5-Diphosphate: A phosphoinositide present in all eukaryotic cells, particularly in the plasma membrane. It is the major substrate for receptor-stimulated phosphoinositidase C, with the consequent formation of inositol 1,4,5-triphosphate and diacylglycerol, and probably also for receptor-stimulated inositol phospholipid 3-kinase. (Kendrew, The Encyclopedia of Molecular Biology, 1994)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)Thiazolesrho-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.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).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)Amoeba: 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.Ca(2+) Mg(2+)-ATPaseModels, Molecular: Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.Microscopy, Video: Microscopy in which television cameras are used to brighten magnified images that are otherwise too dark to be seen with the naked eye. It is used frequently in TELEPATHOLOGY.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.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.Cell Size: The quantity of volume or surface area of CELLS.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.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.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).PhosphoproteinsElectrophoresis, Polyacrylamide Gel: Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.GizzardRhodamines: 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.Adenosine Diphosphate: Adenosine 5'-(trihydrogen diphosphate). An adenine nucleotide containing two phosphate groups esterified to the sugar moiety at the 5'-position.Protein Isoforms: Different forms of a protein that may be produced from different GENES, or from the same gene by ALTERNATIVE SPLICING.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.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 .Zyxin: A zinc-binding phosphoprotein that concentrates at focal adhesions and along the actin cytoskeleton. Zyxin has an N-terminal proline-rich domain and three LIM domains in its C-terminal half.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.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.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.Botulinum Toxins: Toxic proteins produced from the species CLOSTRIDIUM BOTULINUM. The toxins are synthesized as a single peptide chain which is processed into a mature protein consisting of a heavy chain and light chain joined via a disulfide bond. The botulinum toxin light chain is a zinc-dependent protease which is released from the heavy chain upon ENDOCYTOSIS into PRESYNAPTIC NERVE ENDINGS. Once inside the cell the botulinum toxin light chain cleaves specific SNARE proteins which are essential for secretion of ACETYLCHOLINE by SYNAPTIC VESICLES. This inhibition of acetylcholine release results in muscular PARALYSIS.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.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.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.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.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Paxillin: Paxillin is a signal transducing adaptor protein that localizes to FOCAL ADHESIONS via its four LIM domains. It undergoes PHOSPHORYLATION in response to integrin-mediated CELL ADHESION, and interacts with a variety of proteins including VINCULIN; FOCAL ADHESION KINASE; PROTO-ONCOGENE PROTEIN PP60(C-SRC); and PROTO-ONCOGENE PROTEIN C-CRK.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.Cytokinesis: The process by which the CYTOPLASM of a cell is divided.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.Deoxyribonuclease I: An enzyme capable of hydrolyzing highly polymerized DNA by splitting phosphodiester linkages, preferentially adjacent to a pyrimidine nucleotide. This catalyzes endonucleolytic cleavage of DNA yielding 5'-phosphodi- and oligonucleotide end-products. The enzyme has a preference for double-stranded DNA.Protein Multimerization: The assembly of the QUATERNARY PROTEIN STRUCTURE of multimeric proteins (MULTIPROTEIN COMPLEXES) from their composite PROTEIN SUBUNITS.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)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.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.Peptide Fragments: Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.Adaptor Proteins, Signal Transducing: A broad category of carrier proteins that play a role in SIGNAL TRANSDUCTION. They generally contain several modular domains, each of which having its own binding activity, and act by forming complexes with other intracellular-signaling molecules. Signal-transducing adaptor proteins lack enzyme activity, however their activity can be modulated by other signal-transducing enzymesFluorescence Recovery After Photobleaching: A method used to study the lateral movement of MEMBRANE PROTEINS and LIPIDS. A small area of a cell membrane is bleached by laser light and the amount of time necessary for unbleached fluorescent marker-tagged proteins to diffuse back into the bleached site is a measurement of the cell membrane's fluidity. The diffusion coefficient of a protein or lipid in the membrane can be calculated from the data. (From Segen, Current Med Talk, 1995).Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.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.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.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.Time-Lapse Imaging: Recording serial images of a process at regular intervals spaced out over a longer period of time than the time in which the recordings will be played back.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.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.Spectrometry, Fluorescence: Measurement of the intensity and quality of fluorescence.Cadherins: Calcium-dependent cell adhesion proteins. They are important in the formation of ADHERENS JUNCTIONS between cells. Cadherins are classified by their distinct immunological and tissue specificities, either by letters (E- for epithelial, N- for neural, and P- for placental cadherins) or by numbers (cadherin-12 or N-cadherin 2 for brain-cadherin). Cadherins promote cell adhesion via a homophilic mechanism as in the construction of tissues and of the whole animal body.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.Nerve Tissue ProteinsADP Ribose Transferases: Enzymes that transfer the ADP-RIBOSE group of NAD or NADP to proteins or other small molecules. Transfer of ADP-ribose to water (i.e., hydrolysis) is catalyzed by the NADASES. The mono(ADP-ribose)transferases transfer a single ADP-ribose. POLY(ADP-RIBOSE) POLYMERASES transfer multiple units of ADP-ribose to protein targets, building POLY ADENOSINE DIPHOSPHATE RIBOSE in linear or branched chains.Enzyme Activation: Conversion of an inactive form of an enzyme to one possessing metabolic activity. It includes 1, activation by ions (activators); 2, activation by cofactors (coenzymes); and 3, conversion of an enzyme precursor (proenzyme or zymogen) to an active enzyme.Molecular Weight: The sum of the weight of all the atoms in a molecule.Fungal Proteins: Proteins found in any species of fungus.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.Immunohistochemistry: Histochemical localization of immunoreactive substances using labeled antibodies as reagents.Recombinant Proteins: Proteins prepared by recombinant DNA technology.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.NIH 3T3 Cells: A continuous cell line of high contact-inhibition established from NIH Swiss mouse embryo cultures. The cells are useful for DNA transfection and transformation studies. (From ATCC [Internet]. Virginia: American Type Culture Collection; c2002 [cited 2002 Sept 26]. Available from Junctions: Anchoring points where the CYTOSKELETON of neighboring cells are connected to each other. They are composed of specialized areas of the plasma membrane where bundles of the ACTIN CYTOSKELETON attach to the membrane through the transmembrane linkers, CADHERINS, which in turn attach through their extracellular domains to cadherins in the neighboring cell membranes. In sheets of cells, they form into adhesion belts (zonula adherens) that go all the way around a cell.Marine Toxins: Toxic or poisonous substances elaborated by marine flora or fauna. They include also specific, characterized poisons or toxins for which there is no more specific heading, like those from poisonous FISHES.Sarcomeres: The repeating contractile units of the MYOFIBRIL, delimited by Z bands along its length.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.3T3 Cells: Cell lines whose original growing procedure consisted being transferred (T) every 3 days and plated at 300,000 cells per plate (J Cell Biol 17:299-313, 1963). Lines have been developed using several different strains of mice. Tissues are usually fibroblasts derived from mouse embryos but other types and sources have been developed as well. The 3T3 lines are valuable in vitro host systems for oncogenic virus transformation studies, since 3T3 cells possess a high sensitivity to CONTACT INHIBITION.Wiskott-Aldrich Syndrome: A rare, X-linked immunodeficiency syndrome characterized by ECZEMA; LYMPHOPENIA; and, recurrent pyogenic infection. It is seen exclusively in young boys. Typically, IMMUNOGLOBULIN M levels are low and IMMUNOGLOBULIN A and IMMUNOGLOBULIN E levels are elevated. Lymphoreticular malignancies are common.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.Gels: Colloids with a solid continuous phase and liquid as the dispersed phase; gels may be unstable when, due to temperature or other cause, the solid phase liquefies; the resulting colloid is called a sol.Cell Adhesion Molecules: Surface ligands, usually glycoproteins, that mediate cell-to-cell adhesion. Their functions include the assembly and interconnection of various vertebrate systems, as well as maintenance of tissue integration, wound healing, morphogenic movements, cellular migrations, and metastasis.Pyrenes: A group of condensed ring hydrocarbons.Growth Cones: Bulbous enlargement of the growing tip of nerve axons and dendrites. They are crucial to neuronal development because of their pathfinding ability and their role in synaptogenesis.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).)Nonmuscle Myosin Type IIA: A nonmuscle isoform of myosin type II found predominantly in platelets, lymphocytes, neutrophils and brush border enterocytes.Intracellular Signaling Peptides and Proteins: Proteins and peptides that are involved in SIGNAL TRANSDUCTION within the cell. Included here are peptides and proteins that regulate the activity of TRANSCRIPTION FACTORS and cellular processes in response to signals from CELL SURFACE RECEPTORS. Intracellular signaling peptide and proteins may be part of an enzymatic signaling cascade or act through binding to and modifying the action of other signaling factors.Phenotype: The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.Cell Membrane Structures: Structures which are part of the CELL MEMBRANE or have cell membrane as a major part of their structure.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.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.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.Drosophila Proteins: Proteins that originate from insect species belonging to the genus DROSOPHILA. The proteins from the most intensely studied species of Drosophila, DROSOPHILA MELANOGASTER, are the subject of much interest in the area of MORPHOGENESIS and development.GTP Phosphohydrolases: Enzymes that hydrolyze GTP to GDP. EC 3.6.1.-.Fetal Proteins: Proteins that are preferentially expressed or upregulated during FETAL DEVELOPMENT.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)rhoB GTP-Binding Protein: A GTP-BINDING PROTEIN involved in regulating a signal transduction pathway that controls assembly of focal adhesions and actin stress fibers. This enzyme was formerly listed as EC Nucleotide Exchange Factors: Protein factors that promote the exchange of GTP for GDP bound to GTP-BINDING PROTEINS.GTPase-Activating Proteins: Proteins that activate the GTPase of specific GTP-BINDING PROTEINS.Protein-Serine-Threonine Kinases: A group of enzymes that catalyzes the phosphorylation of serine or threonine residues in proteins, with ATP or other nucleotides as phosphate donors.Microvilli: Minute projections of cell membranes which greatly increase the surface area of the cell.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.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.Phosphatidylinositol Phosphates: Phosphatidylinositols in which one or more alcohol group of the inositol has been substituted with a phosphate group.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.Cell Differentiation: Progressive restriction of the developmental potential and increasing specialization of function that leads to the formation of specialized cells, tissues, and organs.Two-Hybrid System Techniques: Screening techniques first developed in yeast to identify genes encoding interacting proteins. Variations are used to evaluate interplay between proteins and other molecules. Two-hybrid techniques refer to analysis for protein-protein interactions, one-hybrid for DNA-protein interactions, three-hybrid interactions for RNA-protein interactions or ligand-based interactions. Reverse n-hybrid techniques refer to analysis for mutations or other small molecules that dissociate known interactions.Ethyldimethylaminopropyl Carbodiimide: Carbodiimide cross-linking reagent.Magnesium: A metallic element that has the atomic symbol Mg, atomic number 12, and atomic weight 24.31. It is important for the activity of many enzymes, especially those involved in OXIDATIVE PHOSPHORYLATION.alpha Catenin: A catenin that binds F-ACTIN and links the CYTOSKELETON with BETA CATENIN and GAMMA CATENIN.Biophysical Phenomena: The physical characteristics and processes of biological systems.Potassium Chloride: A white crystal or crystalline powder used in BUFFERS; FERTILIZERS; and EXPLOSIVES. It can be used to replenish ELECTROLYTES and restore WATER-ELECTROLYTE BALANCE in treating HYPOKALEMIA.Gene Expression Regulation: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control (induction or repression) of gene action at the level of transcription or translation.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.-.Exocytosis: Cellular release of material within membrane-limited vesicles by fusion of the vesicles with the CELL MEMBRANE.Morphogenesis: The development of anatomical structures to create the form of a single- or multi-cell organism. Morphogenesis provides form changes of a part, parts, or the whole organism.Protozoan Proteins: Proteins found in any species of protozoan.Biophysics: The study of PHYSICAL PHENOMENA and PHYSICAL PROCESSES as applied to living things.Myofibroblasts: Spindle-shaped cells with characteristic CONTRACTILE PROTEINS and structures that contribute to the WOUND HEALING process. They occur in GRANULATION TISSUE and also in pathological processes such as FIBROSIS.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.Microinjections: The injection of very small amounts of fluid, often with the aid of a microscope and microsyringes.p21-Activated Kinases: A family of serine-threonine kinases that bind to and are activated by MONOMERIC GTP-BINDING PROTEINS such as RAC GTP-BINDING PROTEINS and CDC42 GTP-BINDING PROTEIN. They are intracellular signaling kinases that play a role the regulation of cytoskeletal organization.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.RNA, Small Interfering: Small double-stranded, non-protein coding RNAs (21-31 nucleotides) involved in GENE SILENCING functions, especially RNA INTERFERENCE (RNAi). Endogenously, siRNAs are generated from dsRNAs (RNA, DOUBLE-STRANDED) by the same ribonuclease, Dicer, that generates miRNAs (MICRORNAS). The perfect match of the siRNAs' antisense strand to their target RNAs mediates RNAi by siRNA-guided RNA cleavage. siRNAs fall into different classes including trans-acting siRNA (tasiRNA), repeat-associated RNA (rasiRNA), small-scan RNA (scnRNA), and Piwi protein-interacting RNA (piRNA) and have different specific gene silencing functions.Elasticity: Resistance and recovery from distortion of shape.Naphthalenesulfonates: A class of organic compounds that contains a naphthalene moiety linked to a sulfonic acid salt or ester.RNA Interference: A gene silencing phenomenon whereby specific dsRNAs (RNA, DOUBLE-STRANDED) trigger the degradation of homologous mRNA (RNA, MESSENGER). The specific dsRNAs are processed into SMALL INTERFERING RNA (siRNA) which serves as a guide for cleavage of the homologous mRNA in the RNA-INDUCED SILENCING COMPLEX. DNA METHYLATION may also be triggered during this process.Lilium: A plant genus in the family LILIACEAE generally growing in temperate areas. The word lily is also used in the common names of many plants of other genera that resemble true lilies. True lilies are erect perennial plants with leafy stems, scaly bulbs, usually narrow leaves, and solitary or clustered flowers.
(1/20287) Tyrosine phosphorylation is required for actin-based motility of vaccinia but not Listeria or Shigella.

Studies of the actin-based motility of pathogens have provided important insights into the events occurring at the leading edge of motile cells [1] [2] [3]. To date, several actin-cytoskeleton-associated proteins have been implicated in the motility of Listeria or Shigella: vasodilator-stimulated phosphoprotein (VASP), vinculin and the actin-related protein complex of Arp2 and Arp3 [4] [5] [6] [7]. To further investigate the underlying mechanism of actin-tail assembly, we examined the localization of components of the actin cytoskeleton including Arp3, VASP, vinculin and zyxin during vaccinia, Listeria and Shigella infections. The most striking difference between the systems was that a phosphotyrosine signal was observed only at the site of vaccinia actin-tail assembly. Micro-injection experiments demonstrated that a phosphotyrosine protein plays an important role in vaccinia actin-tail formation. In addition, we observed a phosphotyrosine signal on clathrin-coated vesicles that have associated actin-tail-like structures and on endogenous vesicles in Xenopus egg extracts which are able to nucleate actin tails [8] [9]. Our observations indicate that a host phosphotyrosine protein is required for the nucleation of actin filaments by vaccinia and suggest that this phosphoprotein might be associated with cellular membranes that can nucleate actin.  (+info)

(2/20287) Transformation mediated by RhoA requires activity of ROCK kinases.

BACKGROUND: The Ras-related GTPase RhoA controls signalling processes required for cytoskeletal reorganisation, transcriptional regulation, and transformation. The ability of RhoA mutants to transform cells correlates not with transcription but with their ability to bind ROCK-I, an effector kinase involved in cytoskeletal reorganisation. We used a recently developed specific ROCK inhibitor, Y-27632, and ROCK truncation mutants to investigate the role of ROCK kinases in transcriptional activation and transformation. RESULTS: In NIH3T3 cells, Y-27632 did not prevent the activation of serum response factor, transcription of c-fos or cell cycle re-entry following serum stimulation. Repeated treatment of NIH3T3 cells with Y-27632, however, substantially disrupted their actin fibre network but did not affect their growth rate. Y-27632 blocked focus formation by RhoA and its guanine-nucleotide exchange factors Dbl and mNET1. It did not affect the growth rate of cells transformed by Dbl and mNET1, but restored normal growth control at confluence and prevented their growth in soft agar. Y-27632 also significantly inhibited focus formation by Ras, but had no effect on the establishment or maintenance of transformation by Src. Furthermore, it significantly inhibited anchorage-independent growth of two out of four colorectal tumour cell lines. Consistent with these data, a truncated ROCK derivative exhibited weak ability to cooperate with activated Raf in focus formation assays. CONCLUSIONS: ROCK signalling is required for both the establishment and maintenance of transformation by constitutive activation of RhoA, and contributes to the Ras-transformed phenotype. These observations provide a potential explanation for the requirement for Rho in Ras-mediated transformation. Moreover, the inhibition of ROCK kinases may be of therapeutic use.  (+info)

(3/20287) Polarized distribution of Bcr-Abl in migrating myeloid cells and co-localization of Bcr-Abl and its target proteins.

Bcr-Abl plays a critical role in the pathogenesis of Philadelphia chromosome-positive leukemia. Although a large number of substrates and interacting proteins of Bcr-Abl have been identified, it remains unclear whether Bcr-Abl assembles multi-protein complexes and if it does where these complexes are within cells. We have investigated the localization of Bcr-Abl in 32D myeloid cells attached to the extracellular matrix. We have found that Bcr-Abl displays a polarized distribution, colocalizing with a subset of filamentous actin at trailing portions of migrating 32D cells, and localizes on the cortical F-actin and on vesicle-like structures in resting 32D cells. Deletion of the actin binding domain of Bcr-Abl (Bcr-AbI-AD) dramatically enhances the localization of Bcr-Abl on the vesicle-like structures. These distinct localization patterns of Bcr-Abl and Bcr-Abl-AD enabled us to examine the localization of Bcr-Abl substrate and interacting proteins in relation to Bcr-Abl. We found that a subset of biochemically defined target proteins of Bcr-Abl redistributed and co-localized with Bcr-Abl on F-actin and on vesicle-like structures. The co-localization of signaling proteins with Bcr-Abl at its sites of localization supports the idea that Bcr-Abl forms a multi-protein signaling complex, while the polarized distribution and vesicle-like localization of Bcr-Abl may play a role in leukemogenesis.  (+info)

(4/20287) Evidence for F-actin-dependent and -independent mechanisms involved in assembly and stability of the medial actomyosin ring in fission yeast.

Cell division in a number of eukaryotes, including the fission yeast Schizosaccharomyces pombe, is achieved through a medially placed actomyosin-based contractile ring. Although several components of the actomyosin ring have been identified, the mechanisms regulating ring assembly are still not understood. Here, we show by biochemical and mutational studies that the S.pombe actomyosin ring component Cdc4p is a light chain associated with Myo2p, a myosin II heavy chain. Localization of Myo2p to the medial ring depended on Cdc4p function, whereas localization of Cdc4p at the division site was independent of Myo2p. Interestingly, the actin-binding and motor domains of Myo2p are not required for its accumulation at the division site although the motor activity of Myo2p is essential for assembly of a normal actomyosin ring. The initial assembly of Myo2p and Cdc4p at the division site requires a functional F-actin cytoskeleton. Once established, however, F-actin is not required for the maintenance of Cdc4p and Myo2p medial rings, suggesting that the attachment of Cdc4p and Myo2p to the division site involves proteins other than actin itself.  (+info)

(5/20287) Cell growth inhibition by farnesyltransferase inhibitors is mediated by gain of geranylgeranylated RhoB.

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)

(6/20287) Association of a myosin immunoanalogue with cell envelopes of Aspergillus fumigatus conidia and its participation in swelling and germination.

A myosin immunoanalogue was identified in conidia of Aspergillus fumigatus by Western blotting, indirect immunofluorescence assay, and gold immunoelectron microscopy with two different antimyosin antibodies. The distribution pattern of this protein was followed during the early stages of germination. A single 180-kDa polypeptide, detected predominantly in a cell envelope extract, was found to cross-react with monoclonal and polyclonal antibodies raised against vertebrate muscle myosin. Immunoelectron microscopy permitted precise localization of this polypeptide, indicating that myosin analogue was mainly distributed along the plasma membrane of resting and swollen conidia. In germinating conidia, indirect immunofluorescence microscopy revealed myosin analogue at the periphery of germ tubes, whereas actin appeared as dispersed punctate structures in the cytoplasm that were more concentrated at the site of germ tube emergence. A myosin ATPase inhibitor, butanedione monoxime, greatly reduced swelling and blocked germination. In contrast, when conidia were treated with cytochalasin B, an inhibitor of actin polymerization, swelling was not affected and germination was only partially reduced. Butanedione monoxime-treated conidia showed accumulation of cytoplasmic vesicles and did not achieve cell wall reorganization, unlike swollen conidia. Collectively, these results suggest an essential role for this myosin analogue in the deposition of cell wall components during germination of A. fumigatus conidia and therefore in host tissue colonization.  (+info)

(7/20287) Yops of Yersinia enterocolitica inhibit receptor-dependent superoxide anion production by human granulocytes.

The virulence plasmid-borne genes encoding Yersinia adhesin A (YadA) and several Yersinia secreted proteins (Yops) are involved in the inhibition of phagocytosis and killing of Yersinia enterocolitica by human granulocytes. One of these Yops, YopH, dephosphorylates multiple tyrosine-phosphorylated proteins in eukaryotic cells and is involved in the inhibition of phagocytosis of Y. enterocolitica by human granulocytes. We investigated whether antibody- and complement-opsonized plasmid-bearing (pYV+) Y. enterocolitica inhibits O2- production by human granulocytes in response to various stimuli and whether YopH is involved. Granulocytes were preincubated with mutant strains unable to express YadA or to secrete Yops or YopH. O2- production by granulocytes during stimulation was assessed by measuring the reduction of ferricytochrome c. PYV+ Y. enterocolitica inhibited O2- production by granulocytes incubated with opsonized Y. enterocolitica or N-formyl-Met-Leu-Phe (f-MLP). This inhibitory effect mediated by pYV did not affect receptor-independent O2- production by granulocytes in response to phorbol myristate acetate, indicating that NADPH activity remained unaffected after activation of protein kinase C. The inhibition of f-MLP-induced O2- production by granulocytes depends on the secretion of Yops and not on the expression of YadA. Insertional inactivation of the yopH gene abrogated the inhibition of phagocytosis of antibody- and complement-opsonized Y. enterocolitica by human granulocytes but not of the f-MLP-induced O2- production by granulocytes or tyrosine phosphorylation of granulocyte proteins. These findings suggest that the specific targets for YopH are not present in f-MLP receptor-linked signal transduction and that other Yop-mediated mechanisms are involved.  (+info)

(8/20287) An RNA switch at the 5' splice site requires ATP and the DEAD box protein Prp28p.

Pre-mRNA splicing requires dramatic RNA rearrangements hypothesized to be catalyzed by ATP-dependent RNA unwindases of the DExD/H box family. In a rearrangement critical for the fidelity of 5' splice site recognition, a base-pairing interaction between the 5' splice site and U1 snRNA must be switched for a mutually exclusive interaction between the 5' splice site and U6 snRNA. By lengthening the U1:5' splice site duplex, we impeded this switch in a temperature-dependent manner and prevented formation of the spliceosome's catalytic core. Using genetics, we identified the DExD/H box protein Prp28p as a potential mediator of the switch. In vitro, the switch requires both Prp28p and ATP. We propose that Prp28p directs isomerization of RNA at the 5' splice site and promotes fidelity in splicing.  (+info)

*  MYH7
An accepted mechanism for this process is that ADP-bound myosin attaches to actin while thrusting tropomyosin inwards, then the ... McKillop DF, Geeves MA (Aug 1993). "Regulation of the interaction between actin and myosin subfragment 1: evidence for three ... actin attachment time as that of β. MHC-β is predominately expressed in the human ventricle, while MHC-α is predominantly ... S1-S2 myosin lever arm rotates ~70° about the converter domain and drives actin filaments towards the M-line. Several mutations ...
*  ACTC1
Polymerization of globular actin (G-actin) leads to a structural filament (F-actin) in the form of a two-stranded helix. Each ... Cardiac alpha actin is a 42.0 kDa protein composed of 377 amino acids. Cardiac alpha actin is a filamentous protein extending ... Actins are highly conserved proteins; the alpha actins are found in muscle tissues and are a major constituent of the ... This isoform differs from the alpha actin that is expressed in skeletal muscle, ACTA1. Alpha cardiac actin is the major protein ...
*  Tropomyosin
Bernstein, BW; Bamburg, JR (1982). "Tropomyosin binding to F-actin protects the F-actin from disassembly by brain actin- ... it was observed that the actin-binding protein actin depolymerisation factor (ADF)/cofilin, a factor that promotes actin ... The actin filament system that is involved in regulating these cellular pathways is more complex than the actin filament ... The tropomyosin dimer has very low affinity for an actin filament and forms no van der waals contacts with actin. It is only ...
*  Gelsolin
The N-terminal is directly involved in the severing of actin. S2 and S3 bind to the actin before the binding of S1 severs actin ... Actin can be cross-linked into a gel by actin cross-linking proteins. Gelsolin can turn this gel into a sol, hence the name ... Gelsolin is an actin-binding protein that is a key regulator of actin filament assembly and disassembly. Gelsolin is one of the ... Gelsolin is a cytoplasmic, calcium-regulated, actin-modulating protein that binds to the barbed ends of actin filaments, ...
*  Actin, alpha 1
Actin alpha 1 which is expressed in skeletal muscle is one of six different actin isoforms which have been identified. Actins ... Alpha actins are a major constituent of the contractile apparatus. Skeletal alpha actin expression is induced by stimuli and ... Actin, alpha 1 has been shown to interact with TMSB4X, MIB2 and PRKCE. Actin ACTB GRCh38: Ensembl release 89: ENSG00000143632 ... and gamma-actin mRNAs: skeletal but not cytoplasmic actins have an amino-terminal cysteine that is subsequently removed". Mol ...
*  Actin
... beta actin ACTC1 - actin, alpha, cardiac muscle 1 ACTG1 - gamma actin 1 ACTG2 - gamma actin 2, smooth muscle, enteric Actin ... Actin Filaments (F-actin) grow from the polymerization of G-actin monomers MBInfo - Actin Binding MBInfo - Actin Nucleation ... of monomeric G-actin. The Arp2/3 complex binds to actin filaments at 70 degrees to form new actin branches off existing actin ... in this way there are three species of actin in a filament: ATP-Actin, ADP+Pi-Actin and ADP-Actin. The amount of each one of ...
*  Beta-actin
... (human gene and protein symbol ACTB/ACTB) is one of six different actin isoforms which have been identified in ... Alpha actins are a major constituent of the contractile apparatus. Beta-actin has been shown to interact with SPTBN2. In ... Beta-actin has been shown to activate eNOS, thereby increasing NO production. An eight-amino acid residue (326-333) in actin ... This is one of the two nonmuscle cytoskeletal actins. Actins are highly conserved proteins that are involved in cell motility, ...
*  Actin (software)
Actin supports an unlimited number of joints, degrees of freedom for those joints, and branches. Actin software supports the ... In 2012, Actin was used to implement the robot control system of the Cyton Gamma series of robotic arms (manufactured by Robai ... Actin can be used for control of most kinds of robots, and provides functions related to robot motion, collision avoidance, and ... Actin was developed for NASA robots, and the software was first demonstrated on a Mitsubishi PA-10 robot while under ...
*  Actin remodeling
Actin-binding proteins (ABPs) aid in the transformation of actin filaments throughout the actin remodeling process. These ... It exists in two forms within eukaryotic cells: globular or G-actin and filament/filamentous or F-actin. Globular actin is the ... Within the cell, the concentrations of G-actin and F-actin continuously fluctuate. The assembly and disassembly of F-actin is ... Simultaneously, older G-actin monomers "fall off" of the pointed end of the microfilament. At the "pointed end" of the F-actin ...
*  Actin depolymerizing factor
... s are a family of microfilament proteins. They are used to regulate actin assembly. Actin ... "Synergy between actin depolymerizing factor/cofilin and profilin in increasing actin filament turnover". J. Biol. Chem. 273 (40 ... "The evolution of compositionally and functionally distinct actin filaments". Journal of Cell Science. 128 (11): 2009-19. doi: ...
*  Actin nucleation core
An actin nucleation core is a protein trimer with three actin monomers. It is called a nucleation core because it leads to the ... Actin protein dimers and trimers are energetically unfavorable.. ...
*  Anti-actin antibodies
In coeliac disease anti-actin antibodies correlated with the level of intestinal damage. In autoimmune hepatitis anti-actin ... Anti-actin antibodies (AAA) are found at increased frequency in certain autoimmune diseases and may be of some diagnostic value ... 2007). "IgA anti-actin antibodies ELISA in coeliac disease: A multicentre study". Digestive and Liver Disease. 39 (9): 814. doi ... In gastric cancer anti-actin antibodies were elevated, along with other antibodies in severe disease with poor outcomes. It has ...
*  Actin-binding protein
... s (also known as ABP) are proteins that bind to actin. This may mean ability to bind actin monomers, or ... ActA Actibind Actin Actinfilin Actinogelin Actin-regulating kinases Actin-Related Proteins Actobindin Actolinkin Actopaxin ... Many actin-binding proteins, including α-actinin, β-spectrin, dystrophin, utrophin and fimbrin, do this through the actin- ... This is a list of actin-binding proteins in alphabetical order. List: 0-9 A B C D E F G H I J K L M N O P Q R S T U V W x Y Z ...
*  Kaptin (actin binding protein)
Bearer EL (1992). "An actin-associated protein present in the microtubule organizing center and the growth cones of PC-12 cells ... Bearer EL, Prakash JM, Li Z (2002). "Actin dynamics in platelets". Int. Rev. Cytol. 217: 137-82. doi:10.1016/S0074-7696(02) ... "Entrez Gene: KPTN kaptin (actin binding protein)". "Body weight data for Kptn". Wellcome Trust Sanger Institute. "Glucose ... a novel actin-associated protein from human blood platelets found in lamellipodia and the tips of the stereocilia of the inner ...
*  Actin remodeling of neurons
Actin treadmilling is the process of turnover of actin filaments where F-actin is rapidly assembled and disassembled. G-actin ... This protein caps the barbed end of F-actin, thus blocking G-actin subunits to bind to the F-actin and allow for actin ... Actin is only able to cause changes that promote LTP through its formation into F-actin. When F-actin is unable to form, LTD is ... G-actin is the monomer form of actin, and is uniformly distributed throughout the axon and the dendrite. F-actin is the polymer ...
*  F-actin capping protein
Unlike gelsolin and severin this protein does not sever actin filaments. The F-actin capping protein is a heterodimer composed ... the F-actin capping protein is a protein which binds in a calcium-independent manner to the fast-growing ends of actin ... The actin filament system, a prominent part of the cytoskeleton in eukaryotic cells, is both a static structure and a dynamic ...
*  Actin assembly-inducing protein
Actin filament assembly generates the force that pushes the bacterium in the mammalian host cytoplasm forward. Continuous actin ... In a mammalian cell the bacterial ActA interacts with the Arp2/3 complex and actin monomers to induce actin polymerization on ... an actin monomer binding protein, which itself promotes polymerization at barbed ends of actin filaments. Furthermore, VASP ... The actin monomer-binding region of ActA has functional properties like the WASP-Homology-2 (WH2) or V domain, but differs in ...
*  Translocated actin-recruiting phosphoprotein
The translocated actin-recruiting phosphoprotein (Tarp) is a protein that may mediate the invasion of epithelial cells by ... "Tyrosine phosphorylation of the Chlamydial effector protein Tarp is species specific and not required for recruitment of actin ... type III translocated protein is tyrosine-phosphorylated at the site of entry and associated with recruitment of actin", ...
*  Actin related protein 2/3 complex inhibitor
... is a protein that in humans is encoded by the ARPIN gene. GRCh38: Ensembl release ... Actin related protein 2/3 complex inhibitor". Retrieved 2017-06-21. Deng WS, Zhang J, Ju H, Zheng HM, Wang J, Wang S, Zhang DL ...
*  Capping protein (actin filament) muscle Z-line, alpha 1
This gene encodes the alpha subunit of the barbed-end actin binding protein. The protein regulates growth of the actin filament ... F-actin-capping protein subunit alpha-1 is a protein that in humans is encoded by the CAPZA1 gene. CAPZA1 is a member of the F- ... 2003). "Linking the T cell surface protein CD2 to the actin-capping protein CAPZ via CMS and CIN85". J. Biol. Chem. 278 (25): ... 2007). "The role of CKIP-1 in cell morphology depends on its interaction with actin-capping protein". J. Biol. Chem. 281 (47): ...
*  Amanita phalloides
Wieland T, Govindan VM (1974). "Phallotoxins bind to actins". FEBS Lett. 46 (1): 351-3. doi:10.1016/0014-5793(74)80404-7. PMID ...
*  Amanita virosa
Benjamin.p217 Wieland T, Govindan VM (1974). "Phallotoxins bind to actins". FEBS Lett. 46 (1): 351-53. doi:10.1016/0014-5793(74 ...
*  Amanita ocreata
Benjamin, Mushrooms: poisons and panaceas, p. 217 Wieland, Thomas; V.M. Govindan (1974). "Phallotoxins bind to actins". FEBS ...
*  Crystal Gayle albums discography
"Actin' Naturally". Amazon. Retrieved 13 November 2010. "The Big Tiger Roars Again, Pt. 2 - Benny Martin: Songs, reviews, ...
... which share significant amino acid sequence identity to conventional actins. Both actins and ARPs have an actin fold, which is ... and expression of two novel actin genes, actin-like-7A (ACTL7A) and actin-like-7B (ACTL7B), from the familial dysautonomia ... Actin-like protein 7A is a protein that in humans is encoded by the ACTL7A gene. The protein encoded by this gene is a member ... "Entrez Gene: ACTL7A actin-like 7A". Human ACTL7A genome location and ACTL7A gene details page in the UCSC Genome Browser. ...
The vascular smooth muscle alpha-actin gene is reactivated during cardiac hypertrophy provoked by load.  JCI - The vascular smooth muscle alpha-actin gene is reactivated during cardiac hypertrophy provoked by load.
These include the gene encoding vascular smooth muscle alpha-actin, the earliest alpha-actin expressed during cardiac ... the prevalence of smooth muscle alpha-actin gene induction was 0.909, versus 0.545 for skeletal muscle alpha-actin (P less than ... whose correlation with cardiac growth at least equals that of skeletal alpha-actin. Induction of smooth muscle alpha-actin was ... The vascular smooth muscle alpha-actin gene is reactivated during cardiac hypertrophy provoked by load.. F M Black, S E Packer ...
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Publications - Actin dynamics  Publications - Actin dynamics
The contractile actin cortex is a thin layer of actin, myosin, and actin-binding proteins that subtends the membrane of animal ... Intermittent depolymerization of actin filaments is caused by photo-induced dimerization of actin protomers. ... The hydrolysis of ATP associated with actin and profilin-actin polymerization is pivotal in cell motility. It is at the origin ... Actin-depolymerizing factor (ADF)/cofilins contribute to cytoskeletal dynamics by promoting rapid actin filament disassembly. ...
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Tropomyosin - master regulator of actin filament function in the cytoskeleton.  - Kent Academic Repository  Tropomyosin - master regulator of actin filament function in the cytoskeleton. - Kent Academic Repository
Third, Tpms achieve these functional outputs by regulating the interaction of actin filaments with myosin motors and actin- ... Tpms are coiled-coil parallel dimers that form a head-to-tail polymer along the length of actin filaments. Yeast only has two ... Each cytoskeletal actin filament contains a homopolymer of Tpm homodimers, resulting in a filament of uniform Tpm composition ... This allows the cell to specify actin filament function in time and space by simply specifying their Tpm isoform composition. ...
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An actin-based protrusion originating from a podosome-enriched region initiates macrophage fusion<...  An actin-based protrusion originating from a podosome-enriched region initiates macrophage fusion<...
An actin-based protrusion originating from a podosome-enriched region initiates macrophage fusion. Molecular biology of the ... An actin-based protrusion originating from a podosome-enriched region initiates macrophage fusion. / Faust, James J.; Balabiyev ... Here, we used live cell imaging to show that actin-based protrusions at the leading edge initiate macrophage fusion. Phase- ... Here, we used live cell imaging to show that actin-based protrusions at the leading edge initiate macrophage fusion. Phase- ...
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Actin - Wikipedia  Actin - Wikipedia
... beta actin ACTC1 - actin, alpha, cardiac muscle 1 ACTG1 - gamma actin 1 ACTG2 - gamma actin 2, smooth muscle, enteric Actin ... Actin Filaments (F-actin) grow from the polymerization of G-actin monomers MBInfo - Actin Binding MBInfo - Actin Nucleation ... of monomeric G-actin. The Arp2/3 complex binds to actin filaments at 70 degrees to form new actin branches off existing actin ... in this way there are three species of actin in a filament: ATP-Actin, ADP+Pi-Actin and ADP-Actin. The amount of each one of ...
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Beta-actin - Wikipedia  Beta-actin - Wikipedia
Beta-actin (human gene and protein symbol ACTB/ACTB) is one of six different actin isoforms which have been identified in ... Alpha actins are a major constituent of the contractile apparatus. Beta-actin has been shown to interact with SPTBN2. In ... Beta-actin has been shown to activate eNOS, thereby increasing NO production. An eight-amino acid residue (326-333) in actin ... This is one of the two nonmuscle cytoskeletal actins. Actins are highly conserved proteins that are involved in cell motility, ...
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actin | PNAS  actin | PNAS
F-actin homeostasis through transcriptional regulation and proteasome-mediated proteolysis Masayuki Onishi, Kresti Pecani, ... NAA80 is actin's N-terminal acetyltransferase and regulates cytoskeleton assembly and cell motility *From the Cover ... Conformational changes in Arp2/3 complex induced by ATP, WASp-VCA, and actin filaments Sofia Espinoza-Sanchez, Lauren Ann ... Cryo-EM reconstruction of AlfA from Bacillus subtilis reveals the structure of a simplified actin-like filament at 3.4-Å ...
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Actin | SpringerLink  Actin | SpringerLink
"ACTIN '92". This conference focused on the fundamental properties and cellular functions of actin and actin- based ... Basic Properties of the Actin Molecule and Actin-Based Microfilament Systems. * Front Matter Pages 1-1 ... Roberto Colombo, University of Milan (Italy). This third gathering of researchers devoted to the study of actin and actin- ... Evidence for an F-Actin Like Conformation in the ACTIN:DNASE I Complex ...
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Neurobiology of Actin | SpringerLink  Neurobiology of Actin | SpringerLink
Actin and its regulatory proteins are the most abundant set of proteins within cells, and they form one of the major cy ... Working with Actin: Methodological Approaches for the Study of Actin in Neurons ... Actin and its regulatory proteins are the most abundant set of proteins within cells, and they form one of the major ... Neurobiology of Actin: From Neurulation to Synaptic Function opens with a chapter that presents the fundamental concepts ...
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Hsp27-Actin Interaction  Hsp27-Actin Interaction
The actin filament (F-actin) is composed of actin monomers (G-actin) polymerized head-to-tail to form two intertwining helical ... Figure 6: Electron microscopy of F-actin ± Hsp27. Negative staining images of 2 M actin (a) and 2 M actin plus 6 M Hsp27 (b) ... EM images of F-actin-Hsp27 demonstrated that Hsp27 is not a strong G-actin sequester. Thus, Hsp27, in vitro, is a weak F-actin ... AnB where A is the actin protomer in F-actin, B is Hsp27 irrespective of its oligomeric state, and n is the actin/Hsp27 molar ...
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Actin patch  Actin patch
The actin patch is a highly dynamic actin structure in fungi required primarily for endocytosis but possibly also coupled to ... Actin patches are highly motile, they first assemble at sites of polarized cell growth and then move slowly and ...
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Actin patch  Actin patch
The actin patch is a highly dynamic actin structure in fungi required primarily for endocytosis but possibly also coupled to ... Actin patches are highly motile, they first assemble at sites of polarized cell growth and then move slowly and ...
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Cipla-Actin -  Cipla-Actin -
A list of US medications equivalent to Cipla-Actin is available on the website. ... Cipla-Actin is a medicine available in a number of countries worldwide. ... Cipla-Actin may be available in the countries listed below.. Ingredient matches for Cipla-Actin. Cyproheptadine. Cyproheptadine ... hydrochloride (a derivative of Cyproheptadine) is reported as an ingredient of Cipla-Actin in the following countries:. *South ...
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actin | Definition & Function |  actin | Definition & Function |
In muscle, two long strands of actin molecules are twisted together to form a thin filament, bundles of which alternate with ... The temporary fusion of actin and myosin results in muscle contraction. ... Actin, protein that is an important contributor to the contractile property of muscle and other cells. ... It exists in two forms: G-actin (monomeric globular actin) and F-actin (polymeric fibrous actin), the form involved in muscle ...
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Actin | Define Actin at  Actin | Define Actin at
Actin definition, a globulin that is present in muscle plasma and that in connection with myosin plays an important role in ... actin. in Medicine. actin. [ăk′tĭn]. n.. *One of the protein components found in muscle, existing as F-actin or G-actin, into ... actin. Historical Examples. of actin. *. "The mare's actin' as if she'd a cup of tea, too," muttered her companion, Ned. ... actin. in Science. actin. [ăk′tĭn]. *A protein found in all eukaryotic cells, forming filaments that make up a main component ...
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Actin Up - Hazel-e |  Actin Up - Hazel-e |
Actin Up (Actin Up). 1 track (3:01). Discover more music, concerts, videos, and pictures with the largest catalogue online at ...
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Actin proteins assemble to protect the genome  Actin proteins assemble to protect the genome
The assembly of polymerized actin with motor proteins at DNA breaks in the nucleus supports the mobility and repair of DNA. ... Actin proteins assemble to protect the genome. The assembly of polymerized actin with motor proteins at DNA breaks in the ... Figure 1 , Nuclear actin polymerizes to preserve genome stability. DNA is packaged with proteins in the nucleus to form a ... Actin filaments form in the nuclei of mammalian cells in response to DNA damage8,9, but their function in DNA repair has also ...
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Actins Many Modes | Science  Actin's Many Modes | Science
Actin is one of the most abundant eukaryotic proteins. It polymerizes to form filamentous actin (F-actin), which plays a key ... A number of disease-causing mutations in the human ACTA1 gene that encodes skeletal muscle actin affect residues in the most ... Actin plasticity is probably required to accommodate its multiple interactions and functions. The authors suggest that the ... The sequence of eukaryotic actin is highly conserved over evolution. One explanation for this is that the many functions of ...
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actin (thing) by fhayashi -  actin (thing) by fhayashi -
Besides the actin cytoskeleton, there are intermediate filaments... ... actin (thing). See all of actin, there is 1 more in this node. ... The actin cytoskeleton appears under the microscope to be ... The toxin comes from the mushroom Amanita phalloides, and it kills you buy mucking with your actin cytoskeleton. Kids, do not ... A protein that makes up one of the three major structural elements in eukaryotic cells. Besides the actin cytoskeleton, there ...
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Inactive Actin | The Scientist Magazine®  Inactive Actin | The Scientist Magazine®
Clathrin-mediated endocytosis shuts down during mitosis in eukaryotic cells because all of the required actin is hoarded by the ... Inactive Actin. Clathrin-mediated endocytosis shuts down during mitosis in eukaryotic cells because all of the required actin ... the actin (purple) is sequestered at the cell cortex, and CME can't proceed because actin is required to help stretch the ... "It seems that whether actin is required for endocytosis really depends on how much work the endocytic machinery has to do to ...
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  • Reports that actin also has functions in the cell nucleus remain controversial 1 , 2 , partly because of the challenges of performing experiments that exclusively perturb the nuclear actin pool without also perturbing actin in the cytoplasm. (
  • Nuclear actin polymerizes to preserve genome stability. (
  • Actin-like protein 6A (ACL6A, also known as BAF53A) is a subunit of the ATP-dependent SWI/SNF-like BAF chromatin remodelling complex, which is essential for hemopoietic stem cell function [ PMID: 23018638 ] and neural development in mammals [ PMID: 17640523 ]. (
  • Arp-T1 is an actin-related protein (Arp) that serves as a component of the cytoskeletal calyx of the mammalian sperm head [ PMID: 12243744 ]. (
  • Mutations in the different genes that regulate actin production in humans can cause muscular diseases, variations in the size and function of the heart as well as deafness. (
  • Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. (
  • 4 report that, in human cells, polymerized actin promotes the processing (resection) of broken DNA ends in chromatin (the compartments involved were not determined) and facilitates a DNA-repair pathway called homologous recombination (HR, not shown), although the underlying mechanism is unclear. (
  • The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. (
  • Here we highlight recent findings on the molecular mechanisms by which actin assembly is regulated in adhesion structures and the molecular basis of the mechanosensitivity of focal adhesions. (
  • Left, scheme of a migrating cell displaying characteristic actin structures: lamellipodial and filopodial actin networks and the three classes of stress fibers (transverse arcs, dorsal stress fibers, ventral stress fibers). (
  • A dynamic polymeric actin structure inside the nucleus is part of the serum response in mammalian tissue culture cells. (
  • Actin patches are highly motile, they first assemble at sites of polarized cell growth and then move slowly and nondirectionally along the cell cortex. (
  • During mitosis, membrane tension is high, the actin (purple) is sequestered at the cell cortex, and CME can't proceed because actin is required to help stretch the clathrin-coated pits to form full vesicles (2). (
  • But actin is different because it absolutely requires the molecular folding help of TRiC. (
  • It seems like this molecular trade-off made the versatility of actin possible", comments Balchin. (
  • Due to the critical role that actin plays in these processes, cancer and cardiovascular research is currently focusing on understanding the molecular processes that occur during actin reorganization. (
  • Hsp27 has been implicated in numerous physiological and pathological processes that involve its interaction with actin and its control of actin dynamics [ 11 - 25 ]. (
  • The migratory cycle is a complex process in which actin dynamics play a central role at every step. (
  • These states reveal allosteric coupling between certain structural features that contribute to plasticity both within and between actin subunits. (
  • These subunits form a cavity inside which actin gets folded. (
  • Using a modified atomic force microscope to probe dendritic actin networks (like those formed in the lamellipodia of motile cells), we observe stress stiffening followed by a regime of reversible stress softening at higher loads. (
  • Actin plasticity is probably required to accommodate its multiple interactions and functions. (
  • Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle contractions. (
  • Interestingly, the toxin phalloidin is used in conjunction with fluorescent dyes to visualize the actin in cells in microscopy . (
  • We offer a selection of phalloidin conjugates to label actin in fixed and permeabilized cells. (
  • Two studies 3 , 4 in Nature now provide the most compelling evidence so far that polymerized actin has roles in cell nuclei in which DNA has been damaged, and that it could be essential for maintaining genome stability. (
  • An early study of the Hsp25 (murine and avian isoform of Hsp27)-actin interaction concluded that Hsp25 was an actin filament barbed-end-capping protein based on limited evidence [ 26 ]. (
  • The results make sense in light of previous studies suggesting that when cell membranes are stretched tight there is a greater need for actin to form clathrin-coated vesicles. (
  • Royle's team is now addressing how the endocytic machinery is able to sense high membrane tension and recruit actin within cells of tissues undergoing physical stretching or in polarized epithelial cells, which have different tensions at their basolateral and apical membranes. (
  • The alpha actins, found in muscle tissues, are a major constituent of the contractile apparatus. (
  • Actin networks in cell migration and organization of nascent adhesions and focal adhesions. (