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 3.6.1.47.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.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 3.6.1.47.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.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 3.6.1.47.Cell 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 3.6.1.47.rac 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 3.6.1.47.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.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 http://www.atcc.org/)Adherens 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 3.6.1.47.Guanine 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.

Tyrosine phosphorylation is required for actin-based motility of vaccinia but not Listeria or Shigella. (1/20287)

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)

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

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)

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

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)

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

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)

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

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)

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

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)

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

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)

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

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)

Pure actin used in research and drug discovery, active actin, actin assay, pyrene actin, fluorescent actin, rhodamine actin, hilyte actin, alexa fluor actin, biotin actin, actin, Actin Protein, Arp2/3 protein, Arp2, Arp3, arp2/3 complex, arp2/3 assay, cofilin, profilin, fodrin, spectrin, tropomyosin, tropomodulin, myosin, actin buffer, actin polymerization buffer, actin cytoskeleton, actin binding proteins, filamin, alpha-actinin, gelsolin.
The heart is a dynamic organ that is made up of multiple cell types including muscle and non-muscle. In general the heart is capable of changing due to many factors including development, physiological response, and pathological conditions. Fibrotic (scarring) and hypertrophic (increase in cell size) diseases of the heart are often associated with messengers (such as calcium (Ca2+)) and pathways that activate proteins normally expressed only in the developing heart. One of these proteins, vascular smooth muscle alpha actin (SMA), is the predominant actin in smooth muscle, but is not normally expressed in the adult heart. However, SMA is activated in response to heart transplant and the associated rejection process (fetal reactivation). The focus of this project is to determine the role of Ca2+ in the regulation of SMA in resident non-muscle cell types of the heart. By using cultured cells we have determined that Ca2+ levels and/or Ca2+ agonists effect previously identified transcription factors ...
Cardiac hypertrophy triggered by mechanical load possesses features in common with growth factor signal transduction. A hemodynamic load provokes rapid expression of the growth factor-inducible nuclear oncogene, c-fos, and certain peptide growth factors specifically stimulate the "fetal" cardiac genes associated with hypertrophy, even in the absence of load. These include the gene encoding vascular smooth muscle alpha-actin, the earliest alpha-actin expressed during cardiac myogenesis; however, it is not known whether reactivation of the smooth muscle alpha-actin gene occurs in ventricular hypertrophy. We therefore investigated myocardial expression of the smooth muscle alpha-actin gene after hemodynamic overload. Smooth muscle alpha-actin mRNA was discernible 24 h after coarctation and was persistently expressed for up to 30 d. In hypertrophied hearts, the prevalence of smooth muscle alpha-actin gene induction was 0.909, versus 0.545 for skeletal muscle alpha-actin (P less than 0.05). ...
Actin, alpha skeletal muscle is a protein that in humans is encoded by the ACTA1 gene. Actin alpha 1 which is expressed in skeletal muscle is one of six different actin isoforms which have been identified. Actins are highly conserved proteins that are involved in cell motility, structure and integrity. Alpha actins are a major constituent of the contractile apparatus. Skeletal alpha actin expression is induced by stimuli and conditions known to cause muscle formation. Such conditions result in fusion of committed cells (satellite cells) into myotubes, to form muscle fibers. Skeletal actin itself, when expressed, causes expression of several other "myogenic genes", which are essential to muscle formation. One key transcription factor that activates skeletal actin gene expression is Serum Response Factor ("SRF"), a protein that binds to specific sites on the promoter DNA of the actin gene. SRF may bring a number of other proteins to the promoter of skeletal actin, such as andogen receptor, and ...
ACTC1 encodes cardiac muscle alpha actin. This isoform differs from the alpha actin that is expressed in skeletal muscle, ACTA1. Alpha cardiac actin is the major protein of the thin filament in cardiac sarcomeres, which are responsible for muscle contraction and generation of force to support the pump function of the heart. Cardiac alpha actin is a 42.0 kDa protein composed of 377 amino acids. Cardiac alpha actin is a filamentous protein extending from a complex mesh with cardiac alpha-actinin (ACTN2) at Z-lines towards the center of the sarcomere. Polymerization of globular actin (G-actin) leads to a structural filament (F-actin) in the form of a two-stranded helix. Each actin can bind to four others. The atomic structure of monomeric actin was solved by Kabsch et al., and closely thereafter this same group published the structure of the actin filament. Actins are highly conserved proteins; the alpha actins are found in muscle tissues and are a major constituent of the contractile apparatus. ...
TY - JOUR. T1 - Actin Filament Bundling and Different Nucleating Effects of Mouse Diaphanous-Related Formin FH2 Domains on Actin/ADF and Actin/Cofilin Complexes. AU - Machaidze, Gia. AU - Sokoll, Andrea. AU - Shimada, Atsushi. AU - Lustig, Ariel. AU - Mazur, Antonina. AU - Wittinghofer, Alfred. AU - Aebi, Ueli. AU - Mannherz, Hans Georg. PY - 2010/11/5. Y1 - 2010/11/5. N2 - Mouse Diaphanous-related formins (mDias) are members of the formin protein family that nucleate actin polymerization and subsequently promote filamentous actin (F-actin) elongation by monomer addition to fast-growing barbed ends. It has been suggested that mDias preferentially recruit actin complexed to profilin due to their proline-rich FH1 domains. During filament elongation, dimeric mDias remain attached to the barbed ends by their FH2 domains, which form an anti-parallel ring-like structure enclosing the filament barbed ends. Dimer formation of mDia-FH2 domains is dependent on their N-terminal lasso and linker subdomains ...
TY - JOUR. T1 - WASH phosphorylation balances endosomal versus cortical actin network integrities during epithelial morphogenesis. AU - Tsarouhas, Vasilios. AU - Liu, Dan. AU - Tsikala, Georgia. AU - Fedoseienko, Alina. AU - Zinn, Kai. AU - Matsuda, Ryo. AU - Billadeau, Daniel D.. AU - Samakovlis, Christos. PY - 2019/12/1. Y1 - 2019/12/1. N2 - Filamentous actin (F-actin) networks facilitate key processes like cell shape control, division, polarization and motility. The dynamic coordination of F-actin networks and its impact on cellular activities are poorly understood. We report an antagonistic relationship between endosomal F-actin assembly and cortical actin bundle integrity during Drosophila airway maturation. Double mutants lacking receptor tyrosine phosphatases (PTP) Ptp10D and Ptp4E, clear luminal proteins and disassemble apical actin bundles prematurely. These defects are counterbalanced by reduction of endosomal trafficking and by mutations affecting the tyrosine kinase Btk29A, and the ...
The current evidence suggests that c-Abl and Arg kinases are activated and recruited by different extracellular stimuli to regulate distinct F-actin structures. Progress has been made in understanding the mechanisms of c-Abl activation by growth factors and the ECM, and in identifying some of the substrates or collaborators of c-Abl in regulating the F-actin cytoskeleton. Because c-Abl is involved in several different F-actin-dependent processes, it is likely to collaborate with other F-actin regulators to determine the dynamic biological output. Multi-protein complexes containing c-Abl or c-Abl substrates may have specific subcellular localization to regulate distinct F-actin structures in various F-actin-dependent processes. Further investigation is now required to characterize the key upstream components in c-Abl cytoskeletal signaling pathways. Moreover, it is important to determine precisely when, where and why the crucial c-Abl substrates are phosphorylated and how this affects the ...
Branched actin networks harness the free energy of actin filament assembly to generate forces required for many important cellular processes (Pollard & Cooper, 2009; Blanchoin et al, 2014). These self‐assembling, cytoskeletal structures push against loads (generally cellular membranes) by promoting nucleation and elongation of actin filaments near the load surface (Pollard et al, 2000). Filament nucleation in branched networks is controlled by membrane‐associated signaling molecules, which recruit nucleation‐promoting factors (NPFs) that, in turn, localize the Arp2/3 complex and stimulate its actin nucleation activity (Pollard et al, 2000; Rotty et al, 2013). Filament elongation near the membrane surface is generally assumed to occur via diffusion‐limited incorporation of actin monomers directly from solution (Pollard et al, 2000), with possible assistance from membrane‐associated actin polymerases, such as formins and Ena/VASP proteins (Dominguez, 2009). The fact that neither formins ...
Most fungi and metazoan cells have the capacity to express multiple isoforms of Tpm, resulting from either different gene products or different post-translational modifications. The biophysical properties of each Tpm filament and the specific way in which they interact with actin can differ significantly. This cooperative interaction with the actin polymer is crucial for Tpm function because it regulates interactions with other actin-binding proteins (e.g. myosins and cofilin) (Bryce et al., 2003), as well as the biophysical and/or dynamic properties of the actin filament. Different Tpms are, therefore, able to impart distinct physical properties to different actin filaments and, thereby, dictate their function. As many cell types can express multiple Tpm isoforms, it is crucial for the viability, function and mobility of a cell to recruit the appropriate Tpm to an actin polymer at the correct place and time (Bach et al., 2009). Indeed, we know that different Tpms are sorted to different actin ...
Work in T cells has demonstrated that actin cytoskeleton rearrangement and lipid raft polarization induced by contact with an APC are dependent on Vav1 activity (10-12). Therefore, early signals upstream of actin polymerization that induce Vav1 phosphorylation must exist. Activation receptor 2B4 on NK cells is not likely to provide such early signals because 2B4 phosphorylation is itself dependent on actin polymerization (20). To test if LFA-1 engagement on NK cells can activate Vav1 upstream of cytoskeleton rearrangements, actin polymerization was blocked by treatment with cytochalasin D and Latrunculin A. As shown in Fig. 3 B, these inhibitors did not block the Vav1 phosphorylation induced by SC2-ICAM cells. In contrast, and consistent with the actin polymerization-dependent phosphorylation of 2B4 (20), the enhancement of Vav1 phosphorylation due to coengagement of 2B4 with LFA-1 was blocked by cytochalasin D and Latrunculin A (Fig. 3 B). These results show that these inhibitors were effective ...
Tropomyosin (Tpm) isoforms are the master regulators of the functions of individual actin filaments in fungi and metazoans. Tpms are coiled-coil parallel dimers that form a head-to-tail polymer along the length of actin filaments. Yeast only has two Tpm isoforms, whereas mammals have over 40. Each cytoskeletal actin filament contains a homopolymer of Tpm homodimers, resulting in a filament of uniform Tpm composition along its length. Evidence for this master regulator role is based on four core sets of observation. First, spatially and functionally distinct actin filaments contain different Tpm isoforms, and recent data suggest that members of the formin family of actin filament nucleators can specify which Tpm isoform is added to the growing actin filament. Second, Tpms regulate whole-organism physiology in terms of morphogenesis, cell proliferation, vesicle trafficking, biomechanics, glucose metabolism and organ size in an isoform-specific manner. Third, Tpms achieve these functional outputs ...
TY - JOUR. T1 - Actin mRNA localizes in the absence of protein synthesis. AU - Sundell, C. L.. AU - Singer, R. H.. PY - 1990. Y1 - 1990. N2 - Actin mRNA is localized in chicken embryo fibroblasts to the distal regions of leading lamellae, but not within the ruffling edges. In this investigation we have addressed the role of actin translation in this process. The translocation of actin mRNA to the cell periphery was studied by monitoring the distribution of actin mRNA in cells during spreading. Within 90 min, actin mRNA moved from a perinuclear to a peripheral distribution. Formation of lamellipodia preceded actin mRNA localization, indicating that localization is not a prerequisite for this event. Neither puromycin (which dissociates ribosomes from mRNA) nor cycloheximide (which stabilizes ribosomes on mRNA) had any effect on this movement of actin mRNA. Anchoring of actin mRNA was studied using cells with peripherally localized actin mRNA. No change in actin mRNA localization was observed for ...
We have shown previously (Schwartz, M. A., and E. J. Luna. 1986. J. Cell Biol. 102: 2067-2075) that actin binds with positive cooperativity to plasma membranes from Dictyostelium discoideum. Actin is polymerized at the membrane surface even at concentrations well below the critical concentration for polymerization in solution. Low salt buffer that blocks actin polymerization in solution also prevents actin binding to membranes. To further explore the relationship between actin polymerization and binding to membranes, we prepared four chemically modified actins that appear to be incapable of polymerizing in solution. Three of these derivatives also lost their ability to bind to membranes. The fourth derivative (EF actin), in which histidine-40 is labeled with ethoxyformic anhydride, binds to membranes with reduced affinity. Binding curves exhibit positive cooperativity, and cross-linking experiments show that membrane-bound actin is multimeric. Thus, binding and polymerization are tightly ...
Disassembly of the epithelial apical junctional complex (AJC), composed of the tight junction (TJ) and adherens junction (AJ), is important for normal tissue remodeling and pathogen-induced disruption of epithelial barriers. Using a calcium depletion model in T84 epithelial cells, we previously found that disassembly of the AJC results in endocytosis of AJ/TJ proteins. In the present study, we investigated the role of the actin cytoskeleton in disassembly and internalization of the AJC. Calcium depletion induced reorganization of apical F-actin into contractile rings. Internalized AJ/TJ proteins colocalized with these rings. Both depolymerization and stabilization of F-actin inhibited ring formation and disassembly of the AJC, suggesting a role for actin filament turnover. Actin reorganization was accompanied by activation (dephosphorylation) of cofilin-1 and its translocation to the F-actin rings. In addition, Arp3 and cortactin colocalized with these rings. F-actin reorganization and disassembly of
Author Summary Actin is one of the best studied, evolutionary conserved and most abundant intracellular proteins. Actin can exists in globular and filamentous functionally distinct forms, and is involved in a variety of biological processes, such as muscle contraction, cell motility, cell division, vesicle and organelle movement, endocytosis, and cell signaling. Here we show a novel function of insect cytoplasmic actin, as an extracellular immune factor. Actin is externalized by insect immune competent cells upon immune challenge with bacteria or bacterial surface components, and once externalized, actin binds with high affinity to the surface of bacteria. A functional role of actins interaction with bacteria is to mediate their killing through either phagocytosis or direct antibacterial action. The globular and filamentous forms of actins appear to play distinct functions as extracellular immune factors. Actin also plays a role as a Plasmodium antagonist as it limits parasite infection of the mosquito
Fission yeast cells use Arp2/3 complex and formin to assemble diverse filamentous actin (F-actin) networks within a common cytoplasm for endocytosis, division, and polarization. Although these homeostatic F-actin networks are usually investigated separately, competition for a limited pool of actin monomers (G-actin) helps to regulate their size and density. However, the mechanism by which G-actin is correctly distributed between rival F-actin networks is not clear. Using a combination of cell biological approaches and in vitro reconstitution of competition between actin assembly factors, we found that the small G-actin binding protein profilin directly inhibits Arp2/3 complex-mediated actin assembly. Profilin is therefore required for formin to compete effectively with excess Arp2/3 complex for limited G-actin and to assemble F-actin for contractile ring formation in dividing cells.
Cell behavior is controlled by extracellular signals that work through signal transduction pathways to regulate the organization of the actin cytoskeleton. Some of these extrinsic signals positively affect the cytoskeleton and induce actin polymerization, but extrinsic signals that negatively regulate and disassemble actin filaments also exist. A family of multidomain proteins, the MICALs, directly associates with Semaphorins, cell surface receptors involved in negative or repulsive cues. Working with purified proteins and in vivo, Hung et al. now find that actin filaments serve as a direct substrate for Micals enzymatic activity. Mical posttranslationally alters actin at its methionine 44 residue, which disrupts the association between actin monomers and cutting actin filaments. Altering the methionine 44 residue makes actin resistant to Mical-mediated disassembly in vitro and in vivo in Drosophila.. R.-J. Hung, C. W. Pak, J. R. Terman, Direct redox regulation of F-actin assembly and ...
Actin and myosin are the two major cytoskeletal proteins implicated in cell motility. As constituents of many cell types, actin and myosin are involved in a myriad of cellular process including locomotion, secretion, cytoplasmic streaming, phagocytosis, and cytokinesis. Actin is one of the most conserved eukaryotic proteins with at least six isoforms. Four of the isoforms represent the differentiation markers of muscle tissues and two are found in almost all cells. There are three α-actins (skeletal, cardiac, and smooth muscle), one β-actin (β-nonmuscle), and two γ-actins (γ-smooth muscle and γ-nonmuscle). Actin isoforms show greater than 90% overall sequence homology, but only 50-60% homology in their 18 NH2-terminal residues. The NH2-terminal region of actin appears to be a major antigenic region and may be involved in the interaction of actin with other proteins such as myosin.. Note: Historically, due to its ubiquitous nature, β-Actin was used as an internal standard for Western ...
Actin plays a major role in the structural integrity and motility of cells as well as in the intracellular dynamics of other macromolecules. Photon Correlation Spectroscopy (PCS) has been used to monitor the diffusion of polystyrene latex spheres (PLS) of different sizes within in vitro polymerized actin solutions under a variety of conditions. Specific actin-binding proteins were added to regulate the actin filament lengths as well as to cross-link filaments together. PCS measurements give information on the mobility of PLS over probing distances equal to the inverse scattering vector magnitude which range from 40 to 420 nm for the data. Results allow estimation of the mean pore sizes within the actin networks as a function of both actin concentration (0.4 - 5 mg/ml) and the presence of actin-binding proteins. Probe diffusion coefficients were measured for PLS samples in length-regulated actin networks at a fixed actin concentration, c (0.65 mg/ml) as c*, the semi-dilute overlap concentration, ...
The connection between T cell activation, plasma membrane order and actin filament dynamics was the main focus of this study. Laurdan and di-4-ANEPPDHQ, membrane order sensing probes, were shown to report only on lipid packing rather than being influenced by the presence of membrane-inserted peptides justifying their use in membrane order studies. These dyes were used to follow plasma membrane order in live cells at 37°C. Disrupting actin filaments had a disordering effect while stabilizing actin filaments had an ordering effect on the plasma membrane, indicating there is a basal level of ordered domains in resting cells. Lowering PI(4,5)P2 levels decreased the proportion of ordered domains strongly suggesting that the connection of actin filaments to the plasma membrane is responsible for the maintaining the level of ordered membrane domains. Membrane blebs, which are detached from the underlying actin filaments, contained a low fraction of ordered domains. Aggregation of membrane components ...
Actin protein derived from rabbit skeletal muscle supplied at |99% purity. Extensive list of citations and additional actin protein research tools available.
Dynamic actin network at the leading edge of the cell is linked to the extracellular matrix through focal adhesions (FAs), and at the same time it undergoes retrograde flow with different dynamics in two distinct zones: the lamellipodium (peripheral zone of fast flow), and the lamellum (zone of slow flow located between the lamellipodium and the cell body). Cell migration involves expansion of both the lamellipodium and the lamellum, as well as formation of new FAs, but it is largely unknown how the position of the boundary between the two flow zones is defined, and how FAs and actin flow mutually influence each other. We investigated dynamic relationship between focal adhesions and the boundary between the two flow zones in spreading cells. Nascent FAs first appeared in the lamellipodium. Within seconds after the formation of new FAs, the rate of actin flow decreased locally, and the lamellipodium/lamellum boundary advanced towards the new FAs. Blocking fast actin flow with cytochalasin D resulted in
To test whether the BODIPY-PtdIns(3,4,5)P3‐induced polarizing pseudopod was based on the actin cytoskeleton, cytochalasin B, an actin polymerization inhibitor, was used. When pre‐treated with cytochalasin B (5 μg ml−1) before loading with BODIPY-PtdIns(3,4,5)P3, no polarizing pseudopodia formed. After cell morphological polarization was initiated, but before full retraction of PtdIns(3,4,5)P3 into the uropod (Fig. 3C), cytochalasin B caused withdrawal of the polarizing pseudopod (Fig. 3A) without an accompanying release of BODIPY-PtdIns(3,4,5)P3, which remained immobilized and polarized (Fig. 3Af). Thus, the formation of the polarizing pseudopod was dependent on actin polymerization, but the tethering PtdIns(3,4,5)P3 was not sensitive to cytochalasin B. This latter evidence might not rule out the cytoskeleton as the immobilization tether because, unlike F‐actin in pseudopodia, the cortical actin network is largely resistant to depolymerization by cytochalasins (Sheterline et al., 1986, ...
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Actin cytoskeleton remodeling requires the coordinated action of a large number of actin binding proteins that reorganize the actin cytoskeleton by promoting polymerization, stabilizing filaments, causing branching, or crosslinking filaments. Palladin is a key cytoskeletal actin binding protein whose normal function is to enable cell motility during development of tissues and organs of the embryo and in wound healing, but palladin is also responsible for regulating the ability of cancer cells to become invasive and metastatic. The membrane phosphoinositide phosphatidylinositol (PI) 4,5-bisphosphate [PI(4,5)P-2] is a well-known precursor for intracellular signaling and a bona fide regulator of actin cytoskeleton reorganization. Our results show that two palladin domains [immunoglobulin (Ig) 3 and 34] interact with the head group of PI(4,5)P-2 with moderate affinity (apparent K-d = 17 mu M). Interactions with PI(4,5)P-2 decrease the actin polymerizing activity of Ig domain 3 of palladin ...
Cell motility plays an important role in many basic biological processes, including embryogenesis, neurite growth, wound healing, inflammation, and cancer metastasis. Motility of crawling cells is dependent on the ability to extend F-actin-rich protrusions, usually in the form of lamellipods (Abercrombie et al. 1970; Chen et al. 1994; Verschueren et al. 1994; Xie et al. 1995). Protrusion of such actin-rich lamellipods in moving cells requires cycles of actin polymerization and depolymerization (actin polymerization transients) (Lauffenburger and Horwitz 1996; Mitchison and Cramer 1996; Bailly et al. 1998a; Condeelis 1998).. Previous studies have demonstrated the requirement for free barbed ends in the control of this cycle (Handel et al. 1990; Symons and Mitchison 1991; Chan et al. 1998). We have shown previously that stimulation of metastatic MTLn3 cells with EGF causes a transient increase in actin nucleation activity resulting from the appearance of free barbed ends at the extreme leading ...
We discuss here some aspects of local and global self-organization of the actomyosin cytoskeleton in the fibroblast-type cells. (1) Locally, the cytoplasm comprises a multi-nodal network formed by small asters of actin filaments nucleated by DAAM1 formin and stabilized by the actin crosslinking protein filamin A. The asters are connected with each other by myosin II, so that the entire system forms a contractile network responsible for the maintenance of the cell shape. (2) Observations of the assembly of myosin-II filament arrays by structured illumination microscopy (SIM) revealed myosin-II "stacks" formed by alignment in register of the myosin-II bipolar filaments associated with actin fibers. In the cells spread over the planar substrate, the numerous myosin stacks apparently form the links between neighboring actin filament bundles (stress-fibers or arcs), maintaining the organization of the actin cytoskeleton. (3) Globally, upon spreading on planar substrate s, cells develop chiral arrays ...
Alpha Cardiac Actin antibody LS-C153366 is an unconjugated rabbit polyclonal antibody to Alpha Cardiac Actin (ACTC1) from human. It is reactive with human, mouse and rat. Validated for ELISA, IHC and WB.
Polyclonal antibody for GAMMA ACTIN/ACTG1 detection. Host: Rabbit.Size: 100μg/vial. Tested applications: IHC-P. Reactive species: Human. GAMMA ACTIN/ACTG1 information: Molecular Weight: 41793 MW; Subcellular Localization: Cytoplasm, cytoskeleton.
Rabbit polyclonal alpha smooth muscle Actin antibody. Validated in WB, ELISA, IHC, ICC/IF and tested in Mouse, Rat, Chicken, Guinea pig, Cow, Dog, Human, Pig. Cited in 1376 publication(s)…
The polymerization of scallop p-like actin is significantly slower than that of skeletal muscle alpha-actin. To reveal which steps of polymerization contribute to this difference, we estimated the efficiency of nucleation of the two actins, the rates of filament elongation at spontaneous and gelsolin-nucleated polymerization and the turnover rates of the filament Subunits at steady-state. Scallop actin nucleated nearly twice less efficient than rabbit actin. In actin filaments with free ends, when dynamics at the barbed ends overrides that at the pointed ends, the relative association rate constants of alpha- and beta-actin were similar, whereas the relative dissociation rate constant of beta-ATP-actin subunits was 2- to 3-fold higher than that of alpha-actin. The 2- to 3-fold faster polymerization of skeletal muscle versus scallop Ca-actin was preserved with gelsolin-capped actin filaments when only polymerization at the pointed end is possible. With gelsolin-induced polymerization, the rate ...
Constitutive centripetal transport of the actin-based cytoskeleton has been detected in cells spreading on a substrate, locomoting fibroblasts and keratocytes, and non-locomoting serum-deprived fibroblasts. These results suggest a gradient of actin assembly, highest in the cortex at the cytoplasm-membrane interface and lowest in the non-cortical perinuclear cytoplasm. We predicted that such a gradient would be maintained in part by phosphoinositide-regulated actin binding proteins because the intracellular free Ca2+ and pH are low and spatially constant in serum-deprived cells. The cytoplasm-membrane interface presents one surface where the assembly of actin is differentially regulated relative to the non-cortical cytoplasm. Several models, based on in vitro biochemistry, propose that phosphoinositide-regulated actin binding proteins are involved in local actin assembly. To test these models in living cells using imaging techniques, we prepared a new fluorescent analog of actin that bound ...
Rabbit polyclonal Actin antibody validated for WB, IHC and tested in Human and Rat. Referenced in 2 publications and 1 independent review. Immunogen…
Actin is a major component of the cytoskeleton and is present as two isoforms in non-muscle cells: β- and γ-cytoplasmic actin. These isoforms are strikingly conserved, differing by only four N-terminal amino acids. During spread from infected cells, vaccinia virus (VACV) particles induce localized actin nucleation that propel virus to surrounding cells and facilitate cell-to-cell spread of infection. Here we show that virus-tipped actin comets are composed of β- and γ-actin. We employed isoform-specific siRNA knockdown to examine the role of the two isoforms in VACV-induced actin comets. Despite the high level of similarity between the actin isoforms, and their colocalization, VACV-induced actin nucleation was dependent exclusively on β-actin. Knockdown of β-actin led to a reduction in the release of virus from infected cells, a phenotype dependent on virus-induced Arp2/3 complex activity. We suggest that local concentrations of actin isoforms may regulate the activity of cellular actin ...
TY - JOUR. T1 - Myosin II contributes to cell-scale actin network treadmilling through network disassembly. AU - Wilson, Cyrus A.. AU - Tsuchida, Mark A.. AU - Allen, Greg M.. AU - Barnhart, Erin L.. AU - Applegate, Kathryn T.. AU - Yam, Patricia T.. AU - Ji, Lin. AU - Keren, Kinneret. AU - Danuser, Gaudenz. AU - Theriot, Julie A.. PY - 2010/5/20. Y1 - 2010/5/20. N2 - Crawling locomotion of eukaryotic cells is achieved by a process dependent on the actin cytoskeleton: protrusion of the leading edge requires assembly of a network of actin filaments, which must be disassembled at the cell rear for sustained motility. Although ADF/cofilin proteins have been shown to contribute to actin disassembly, it is not clear how activity of these locally acting proteins could be coordinated over the distance scale of the whole cell. Here we show that non-muscle myosin II has a direct role in actin network disassembly in crawling cells. In fish keratocytes undergoing motility, myosin II is concentrated in ...
Rabbit Polyclonal Anti-alpha-Smooth Muscle Actin Antibody. Mesenchymal Cell Marker. Validated: WB, IP. Tested Reactivity: Human. 100% Guaranteed.
Image analysis was performed in MATLAB. To quantify actin structure, we defined the actin distribution parameter (ADP) as the standard deviation of pixel intensity within a region of interest (ROI). A higher ADP indicates the presence of high contrast features including stress fibers. The ROI was defined as the inner 50% of the cellular area. Cell area was calculated based on cell shape, determined by a manual trace of the cortical actin band in the apical region. Quantification was performed on all cells in all 5 locations averaged per specimen (avg N = 193 cells/specimen). One-way ANOVA was used for statistical analysis.. Results : At 0 , t , 12 hrs, ECs exhibited a cortical double-banded actin structure as well as stress fibers spanning the entire cell (Fig. 1, Fig. 2A). At increasing DPT, the double band disappeared and actin distribution became increasingly homogeneous and diffuse throughout the cytoplasm. As a result, ADP significantly decreased (p=0.007 for 0 , t , 12 hrs vs. 24 , t , 48 ...
beta Actin antibody Mouse Monoclonal from Proteintech validated in Western Blot (WB), Immunoprecipitation (IP), Immunohistochemistry (IHC), Immunofluorescence (IF), Flow Cytometry (FC), Enzyme-linked Immunosorbent Assay (ELISA) applications. This antibody reacts with human, mouse, rat, hamster, zebrafish,monkey samples. Cat.No. 66009-1-Ig. KD/KO Validated.
GenScript THETM beta Actin Antibody [HRP], mAb, Mouse is HRP conjugated THETM beta Actin Antibody, mAb, Mouse (A00702) purified from mice ascites by protein G affinity column. This product provides a useful and serves as a specific tool in the study of the intracellular distribution of ß-actin a...
Treatment with SMIFH2 decreases the actin level in oocytes and impairs spindle formation.A. Treatment with SMIFH2 decreases the cortical actin level in maturing
Proteins bind to filamentous actin (F-actin) through distinct actin binding modules. In this video we demonstrate the procedure of...
Mouse Monoclonal Anti-pan Actin Antibody (HHF35) [DyLight 405]. Muscle Cell Marker. Validated: WB, Flow, ICC/IF, IHC-Fr, IHC-P. Tested Reactivity: Human, Mouse, Rat, and more. 100% Guaranteed.
Functional differentiation is orchestrated by precise growth-regulatory controls conveyed by the tissue microenvironment. Cues from laminin 111 (LN1) lower transcription and suppress mammary epithelial cell growth in culture, but how LN1 induces quiescence is unknown. Recent literature points to involvement of nuclear β-actin in transcriptional regulation. Here, we show that quiescence induced by growth factor withdrawal, or LN1 addition, rapidly decreases nuclear β-actin. LN1, but not other extracellular matrix (ECM) molecules, decreases the levels of nuclear β-actin and destabilizes RNA polymerase (RNA Pol) II and III binding to transcription sites, leading to a dramatic drop in transcription and DNA synthesis. Constitutive overexpression of globular β-actin in the nucleus reverses the effect of LN1 on transcription and RNA Pol II association and prevents the cells from becoming quiescent in the presence of LN1. The physiological relevance of our findings was verified by identifying a ...
Monoclonal Antibody for studying ACTA1 (alpha actin, skeletal muscle)/ACTA2 (alpha actin, smooth muscle)/ACTC1 (alpha cardiac actin)/ACTG1 (gamma actin cytoplasmic nonmuscle)/ACTG2 (gamma actin, cytoplasmic)/beta-Actin in the Cytoskeletal Signaling research area.
Leukocytes arrested on inflamed endothelium via integrins are subjected to force imparted by flowing blood. How leukocytes respond to this force and resist detachment is poorly understood. Live-cell imaging with Lifeact-transfected U937 cells revealed that force triggers actin polymerization at upstream α4β1 integrin adhesion sites and the adjacent cortical cytoskeleton. Scanning electron microscopy revealed that this culminates in the formation of structures that anchor monocyte adhesion. Inhibition of actin polymerization resulted in cell deformation, displacement, and detachment. Transfection of dominant-negative constructs and inhibition of function or expression revealed key signaling steps required for upstream actin polymerization and adhesion stabilization. These included activation of Rap1, phosphoinositide 3-kinase γ isoform, and Rac but not Cdc42. Thus, rapid signaling and structural adaptations enable leukocytes to stabilize adhesion and resist detachment forces. ...
Clone REA___ recognizes the human, mouse and rat β-Actin, which belongs to the actin family of highly conserved globular multi-functional proteins that play a role in various types of cell motility. They are able to form microfilaments and are found in all eukaryotic cells. β-Actin is a nonmuscle cytoskeletal actin and exists in most cell types as a component of the cytoskeleton and as a mediator of internal cell motility.Additional information: Clone REA___ displays negligible binding to Fc receptors. - Ireland
For directional movement, eukaryotic cells depend on the proper organization of their actin cytoskeleton. This engine of motility is made up of highly dynamic nonequilibrium actin structures such as flashes, oscillations, and traveling waves. In Dictyostelium, oscillatory actin foci interact with signals such as Ras and phosphatidylinositol 3,4,5-trisphosphate (PIP3) to form protrusions. However, how signaling cues tame actin dynamics to produce a pseudopod and guide cellular motility is a critical open question in eukaryotic chemotaxis. Here, we demonstrate that the strength of coupling between individual actin oscillators controls cell polarization and directional movement. We implement an inducible sequestration system to inactivate the heterotrimeric G protein subunit Gβ and find that this acute perturbation triggers persistent, high-amplitude cortical oscillations of F-actin. Actin oscillators that are normally weakly coupled to one another in wild-type cells become strongly synchronized following
Drosophila S2 cells offer a powerful tool to study in vivo dynamics and organization of the actin cytoskeleton. When plated on the lectin, concanavalin A, S2 cells attach and spread on the substrate to form a circumferential actin-based lamellae. The susceptibility of these cells to gene inhibition using RNAi makes them a very tractable system to dissect the molecular machinery involved in lamellipod formation. The figure shows a control S2 (upper left) in comparison with cells depleted of capping protein beta (upper right), cofilin (lower left), and Rho1 (lower right). The hyper-ruffled morphology produced by capping protein RNAi is consistent with its role in terminating actin filament elongation - in the absence of the protein, actin filaments polymerization pushes on the membrane in an unregulated manner. Depletion of cofilin, a factor required for actin filament turnover, produces cells that are unable to spread due to abnormal accumulations of f-actin at their cortex. RNAi-inhibition of ...
Wieland T, Govindan VM (1974). "Phallotoxins bind to actins". FEBS Lett. 46 (1): 351-3. doi:10.1016/0014-5793(74)80404-7. PMID ...
Benjamin.p217 Wieland T, Govindan VM (1974). "Phallotoxins bind to actins". FEBS Lett. 46 (1): 351-53. doi:10.1016/0014-5793(74 ...
Benjamin, Mushrooms: poisons and panaceas, p. 217 Wieland, Thomas; V.M. Govindan (1974). "Phallotoxins bind to actins". FEBS ...
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 ...
"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. ...
Intro Actin Like... (featuring Laroo) So Cold That's My Name I Was Told (featuring G-Stack) Party Jumpin (featuring The Jacka) ...
... which share significant amino acid sequence identity to conventional actins. Both actins and ARPs have an actin fold, which is ... "Entrez Gene: ACTL6B actin-like 6B". Oma Y, Nishimori K, Harata M (February 2003). "The brain-specific actin-related protein ... Actin-like protein 6B is a protein that in humans is encoded by the ACTL6B gene. The protein encoded by this gene is a member ... Harata M, Mochizuki R, Mizuno S (1999). "Two isoforms of a human actin-related protein show nuclear localization and mutually ...
Unlike the motility of actin-based cells, which is based on polar cytoskeletal elements such as actin monomers or tubulin ... In contrast to actin, MSP lacks an ATP-binding site. However, it was noticed that ATP is required for MSP filament assembly at ... The two main differences between actin and MSP is that MSP does not bind ATP and the lack of polarity in MSP, thus disabling ... Roberts TM, Stewart M (April 2000). "Acting like actin. The dynamics of the nematode major sperm protein (msp) cytoskeleton ...
The CH domain is involved in actin binding in some members of the family. However, in calponins there is evidence that the CH ... Hartwig JH (1995). "Actin-binding proteins. 1: Spectrin super family". Protein Prof. 2 (7): 703-800. PMID 7584474. Gimona M, ... Saraste M, Castresana J (1995). "Does Vav bind to F-actin through a CH domain?". FEBS Lett. 374 (2): 149-151. doi:10.1016/0014- ... Calponin homology domain (or CH domain) is a family of actin binding domains found in both cytoskeletal proteins and signal ...
Elongating the actin filament occurs when free-actin (G-actin) bound to ATP associates with the filament. Under physiological ... Association of G-actin into F-actin is regulated by the critical concentration outlined below. Actin polymerization can further ... The critical concentration is the concentration of either G-actin (actin) or the alpha,beta- tubulin complex (microtubules) at ... Profilin induces ATP binding to G-actin so that it can be incorporated onto the positive end of the filament. Two main theories ...
In fact, annexin A-II is itself an actin-binding protein and therefore it can form a region of interaction with actin by means ... Hayes MJ, Rescher U, Gerke V, Moss SE (August 2004). "Annexin-actin interactions". Traffic. 5 (8): 571-6. doi:10.1111/j.1600- ... in the cell membrane and facilitate actin assembly near the membrane. More recently, annexin scaffolding functions have been ... bisphosphate binding protein recruited to actin assembly sites at cellular membranes". J. Cell Sci. 117 (Pt 16): 3473-80. doi: ...
... which share significant amino acid sequence identity to conventional actins. Both actins and ARPs have an actin fold, which is ... Actin-like protein 6A is a protein that in humans is encoded by the ACTL6A gene. This gene encodes a family member of actin- ... Together with beta-actin, it is required for maximal ATPase activity of BRG1, and for the association of the BAF complex with ... "Entrez Gene: ACTL6A actin-like 6A". Saladi SV, Ross K, Karaayvaz M, Tata PR, Mou H, Rajagopal J, Ramaswamy S, Ellisen LW (2017 ...
Quit Actin' 02. Hypnotic 04. Special Occasion 01. Magic 02. Charlie, Last Name Wilson 05. No Words 01. I Need An Angel 04. In ...
"Actin Different - Belly". SongLyrics.com. Retrieved 2017-07-26. Quiet On The Set Remix Feat Rico Love and Velous, retrieved ...
Quit Actin' (track listing). Ray J. Sanctuary Urban. 2005. SURDJ-85685-1. "Urban Renewal: Featuring the Songs of Phil Collins ...
Lee E, De Camilli P (2002). "Dynamin at actin tails". Proc. Natl. Acad. Sci. U.S.A. 99 (1): 161-6. doi:10.1073/pnas.012607799. ... Orth JD, McNiven MA (2003). "Dynamin at the actin-membrane interface". Curr. Opin. Cell Biol. 15 (1): 31-9. doi:10.1016/S0955- ... Dynamins bind many proteins that bind actin and other cytoskeletal proteins. Dynamins can also self-assemble, a process that ... 2003). "Dynamin2 and cortactin regulate actin assembly and filament organization". Curr. Biol. 12 (21): 1852-7. doi:10.1016/ ...
Kruppa AJ, Kendrick-Jones J, Buss F (2016). "Myosins, Actin and Autophagy". Traffic (Copenhagen, Denmark). 17 (8): 878-90. doi: ...
1 S100 calcium-binding protein A1 TATA-binding protein Actin-binding protein Most actin binding proteins bind on the actin ... Actin-Monomer-Binding Proteins. New York, NY: Landes Bioscience and Springer Science+Business Media, LLC. p. 107. ...
According to the Fences and pickets model, plasma membrane is compartmentalized by actin-based membrane-skeleton "fences", that ... temporal actin filament brackage; membrane molecules have sufficient kinetic energy to cross the barrier While simple Brownian ... occur when cytoplasmic domains collide with the actin-based membrane skeleton; and anchored-transmembrane protein "pickets". ...
Actin is also believed to be important. Axe EL, Walker SA, Manifava M, Chandra P, Roderick HL, Habermann A, Griffiths G, ... Kruppa AJ, Kendrick-Jones J, Buss F (2016). "Myosins, Actin and Autophagy". Traffic (Copenhagen, Denmark). 17 (8): 878-90. doi: ... Aguilera MO, Berón W, Colombo MI (2012). "The actin cytoskeleton participates in the early events of autophagosome formation ...
Arnold, Chuck (February 1, 1994). "She's Just Actin' Jackson". Philly.com. Philadelphia Media Network. Retrieved July 5, 2014. ...
These structures may be composed of myosin and actin, which are part of the cell's cytoskeleton. If this is the case these ... White, RG; Badelt, K; Overall, RL; Vesk, M (1994). "Actin associated with plasmodesmata". Protoplasma. 180: 169-184. doi: ...
F-actin, while processive runlengths are shorter on older (ADP-rich) F-actin. Myosin VI is an unconventional myosin motor, ... It walks along actin filaments, travelling towards the pointed end (- end) of the filaments. Myosin VI is thought to transport ... "Actin Age Orchestrates Myosin-5 and Myosin-6 Run Lengths". Current Biology. 25: 2057-2062. doi:10.1016/j.cub.2015.06.033. PMC ... The binding of a new ATP molecule will release myosin from actin. ATP hydrolysis within the myosin will cause it to bind to ...
F-actin capping protein. FNDC38 - Represses transcription. Tumour metastasis. Raldh2/aldh1a2 - Represses transcription. ...
... dc. ... A secondary investigation was performed in U2OS cells by probing Heat Shock Protein 90 (Hsp90) and its role in folding actin ... The Inhibition of Nonmuscle Myosin IIA and Actin Interactions in Human Osteosarcoma Cells to Stymie Metastatic Disease. en_US. ... generated from filaments consisting of both actin and nonmuscle myosin IIA. These filaments generate significantly more force ...
Figure 1 Tying a knot in an actin filament. Explanatory drawings are added in images 3 7. In images 3 and 7, the microscope ...
F-actin homeostasis through transcriptional regulation and proteasome-mediated proteolysis Masayuki Onishi, Kresti Pecani, ... NAA80 is actins 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 ...
"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 ...
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 ...
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 ...
ACTA1 gene mutations that cause actin-accumulation myopathy may affect the way the skeletal α-actin protein binds to ATP. ATP ... This gene provides instructions for making a protein called skeletal alpha (α)-actin, which is a member of the actin protein ... Mutations in the skeletal muscle alpha-actin gene in patients with actin myopathy and nemaline myopathy. Nat Genet. 1999 Oct;23 ... and is important in the formation of thin filaments from individual actin molecules. . Dysfunctional actin-ATP binding may ...
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 ...
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 ...
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 mares actin as if shed 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 ...
Actin Up (Actin Up). 1 track (3:01). Discover more music, concerts, videos, and pictures with the largest catalogue online at ...
A list of US medications equivalent to Cipla-Actin is available on the Drugs.com 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 ...
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 ...
... Claire Russell c.russell at ic.ac.uk Fri Feb 26 12:22:32 EST 1999 *Previous message: sex hormones ... Hello everyone, I have been using phallodin to look at actin distribution but was wondering if anyone knows of an antibody that ...
... 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 ...
Actin-propelled invasive membrane protrusions promote fusogenic protein engagement during cell-cell fusion. ... Actin-propelled[All Fields] AND Invasive[All Fields] AND ("membranes"[MeSH Terms] OR "membranes"[All Fields] OR "membrane"[All ... Search: Actin-propelled Invasive Membrane Protrusions *. Format. Summary. Summary (text). Abstract. Abstract (text). MEDLINE. ...
... Celine Alkemade. Collaborators: Gijsje Koenderink (AMOLF), Anna Akhmanova (University ... The actin and microtubule (MT) cytoskeletons are key structural components that allow and coordinate rapid and sometimes ... For example, we have control over density, geometry, and crosslinking of the actin network, as is shown in Figure 2. Coupling ... For a more profound and quantitative understand of actin-MT crosstalk, we use a simple yet realistic reconstituted model system ...
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 ...
... into the Act88F flight muscle-specific actin gene. We challenged these variant actins to replace the native protein by ... Functional nonequivalence of Drosophila actin isoforms.. Fyrberg EA1, Fyrberg CC, Biggs JR, Saville D, Beall CJ, Ketchum A. ... We conclude that actin isoform sequences are not equivalent and that effects of the amino acid replacements, while minor ... We sequenced the six genes that encode conventional Drosophila actins and found that they specify amino acid replacements in 27 ...
Actin-like protein 6A (ACL6A, also known as BAF53A) is a subunit of the ATP-dependent SWI/SNF-like BAF chromatin remodelling ...
Novel actin-related proteins Arp-T1 and Arp-T2 as components of the cytoskeletal calyx of the mammalian sperm head.. Exp. Cell ... Arp-T1 is an actin-related protein (Arp) that serves as a component of the cytoskeletal calyx of the mammalian sperm head [PMID ...
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 ...
The actin-binding protein α-actinin, that bundles actin filaments, plays a major role in the organization of the actin network ... Talin contains three actin-filament- (F-actin-) binding domains located in the FERM domain (ABD1), the rod domain (ABD2), and ... Regulation of Actin Assembly by Vinculin. Vinculin is a large actin binding protein of 1066 amino acids present in FAs. ... D. Chereau and R. Dominguez, "Understanding the role of the G-actin-binding domain of Ena/VASP in actin assembly," Journal of ...
... which require actin assembly that is regulated by specialized actin nucleation factors. There is a large variety of different ... Nucleating actin for invasion Nat Rev Cancer. 2011 Mar;11(3):177-87. doi: 10.1038/nrc3003. Epub 2011 Feb 10. ... Studies of the mechanisms of various actin nucleation factors that are involved in cancer cell function may ultimately provide ... actin nucleators in human cells, such as formins, spire and Arp2/3-regulating proteins, and the list is likely to grow. ...
If you know of any papers that use this antibody, please contact us at antibodies [at] alzforum [dot] org for consideration in the References section.. ...
  • Movement within a cell is created from sarcomeric-like contractions in the lamellipodium (a cell's outermost section) generated from filaments consisting of both actin and nonmuscle myosin IIA. (kzoo.edu)
  • A secondary investigation was performed in U2OS cells by probing Heat Shock Protein 90 (Hsp90) and its role in folding actin polymers through the Hsp90 inhibitor Tanespimycin. (kzoo.edu)
  • Actin therefore contributes to processes such as the intracellular transport of vesicles and organelles as well as muscular contraction and cellular migration. (wikipedia.org)
  • To anchor the protrusion, the cell front interacts with the extracellular matrix (ECM) by forming nascent adhesions (or focal complexes) that are connected to the intracellular lamellipodial actin network. (hindawi.com)
  • The present study used a new technique involving intracellular and extracellular application of rhodamine-phalloidin to conventional hippocampal slices to test whether induction of LTP by naturalistic patterns of afferent activity selectively increases actin polymerization in juvenile to young adult spines. (jneurosci.org)
  • However, AITC-treated seedlings of all transgenic lines tested displayed morphologies and intracellular movements similar to that of the corresponding untreated and control-treated plants, following overnight incubation in an AITC-absent environment, indicating that AITC-induced decline in actin-related movements is a reversible process. (mdpi.com)
  • Sporsheim B, Øverby A, Bones AM. Allyl Isothiocyanate Inhibits Actin-Dependent Intracellular Transport in Arabidopsis thaliana . (mdpi.com)
  • We have previously shown that changes in the cytoplasmic F- and G-actin ratios reflect bladder cancer risk. (cdc.gov)
  • To determine whether nuclear actin is also altered and how nuclear and cytoplasmic actin alterations are interrelated in transformation, an in vitro model of carcinogen-induced transformation consisting of 2 human uroepithelial cell lines immortalized by infection with SV-40 was studied. (cdc.gov)
  • Cytoplasmic and nuclear F- and G-actin were determined by QFIA on individual cells using fluorochrome-labeled phallicidin and DNase, I, respectively. (cdc.gov)
  • Before exposure to 4-ABP, the PC cells had lower cytoplasmic F-actin content, higher cytoplasmic G-actin content, but similar levels of nuclear G- and F-actin in comparison to the BC cells. (cdc.gov)
  • After incubation with 4-ABP, F-actin decreased and G-actin increased in both cytoplasm and nuclei of PC cells and cytoplasmic F-actin fibers were lost, but only cytoplasmic actin was altered in the BC cells. (cdc.gov)
  • Binding of F-actin to the F-actin binding domain may #=GF CC result in cytoplasmic retention and subcellular distribution of #=GF CC the protein, as well as possible inhibition of protein function #=GF CC . (genome.jp)
  • Complementary DNA sequence of a human cytoplasmic actin. (origene.com)
  • Polymerization of actin also increases the mobility of DNA breaks that will be repaired by HR and the ability of a subset of DNA breaks to form clusters in the nucleus. (nature.com)
  • Jasplakinolide induces the polymerization of actin and stabilizes actins monomeric form. (news-medical.net)
  • These results indicate that near-threshold conditions for inducing stable potentiation cause the rapid polymerization of actin in mature spines and suggest that the effect is both sufficiently discrete to satisfy the synapse-specificity rule of LTP as well as rapid enough to participate in the initial stages of LTP consolidation. (jneurosci.org)
  • 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. (nature.com)
  • In the cytosol (fluid component of cytoplasm), actin is predominantly bound to adenosine triphosphate , or ATP. (newworldencyclopedia.org)
  • Being organized in a dynamic vesicle-actin network allows vesicles to move in a local random manner and a global directed manner at the same time: they can reach any position in the cytoplasm, but also move directionally to the cell surface as a collective. (warwick.ac.uk)
  • First, is spine actin polymerization actually responsible for the stabilization of LTP? (pnas.org)
  • Here we used selective antagonists to test the specific prediction that β1 integrins are responsible for the spine actin changes that accompany LTP. (pnas.org)
  • 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. (wikipedia.org)
  • We sequenced the six genes that encode conventional Drosophila actins and found that they specify amino acid replacements in 27 of 376 positions. (nih.gov)
  • To be sure that the actin response is truly associated to the resistance phenotype, the researchers conducted experiments in which genes were silenced to impair actin polymerization. (innovations-report.com)
  • The majority of actin genes are interrupted by introns , with up to 6 introns in any of 19 well-characterised locations. (wikidoc.org)
  • Higher plants contain families of actin-encoding genes that are divergent and differentially expressed. (genetics.org)
  • DNA sequences are provided for production of beta -actin or untranslated regions of beta -actin genes may be employed in conjunction with genes encoding for polypeptides for efficient expression in mammalian hosts. (freepatentsonline.com)
  • ABPs-Denotes genes that interact directly with actin or that are members of well-defined actin-associated complexes (e.g. (upstate.edu)
  • 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). (hindawi.com)
  • Invasive cell migration requires the formation of various structures, such as invadopodia and pseudopodia, which require actin assembly that is regulated by specialized actin nucleation factors. (nih.gov)
  • Royle and colleagues first observed that in HeLa cells, cortactin, a protein that activates actin polymerization, was present in clathrin structures during interphase but was greatly reduced during mitosis. (the-scientist.com)
  • These structures provide architectural specificities for different regions of the cell, and can also organize into more complex actin-based machineries. (mpg.de)
  • 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. (nature.com)
  • Still, Traub suspects that actin unavailability is not the only regulatory mechanism controlling endocytosis. (the-scientist.com)
  • The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. (innovations-report.com)
  • This study reveals an unexpected actin-dependent but microtubule-independent mechanism for long-range transport of vesicles in mouse oocytes. (warwick.ac.uk)
  • Dr Schuh will also talk about the actin-dependent mechanism of asymmetric spindle positioning in mouse oocytes. (warwick.ac.uk)
  • In addition to providing a distinct cellular mechanism for increasing F-actin, this manipulation targeted only a subset of cells, thus eliminating potentially confounding non-cell-autonomous effects that might be expected from bath application of a drug. (jneurosci.org)
  • the conversion of G-actin to F-actin is catalyzed by small concentrations of magnesium ion, is reversible, and is accompanied by the conversion of the bound ATP molecule to ADP and phosphate and the conversion of one reactive -thiol group to an unreactive form. (thefreedictionary.com)
  • In this study we now present direct chemical evidence for the existence of a short-lived species, an activated form of G-actin, which can be detected by changes in the accessibility of the free thiol groups on the G-actin molecule when modified by a specific thiol-group-targeted reagent, 7-dimethylamino-4-methyl-3-N-maleimidylcoumarin (DACM). (biomedsearch.com)
  • Such changes at least involve certain portions of the G-actin molecule that contain Cys-217 and Cys-374. (biomedsearch.com)
  • F-actin is a two-stranded helical polymer. (springer.com)
  • Sun and Bamji (2011) took this one step further by increasing F-actin polymer content through two distinct approaches. (jneurosci.org)
  • These results provide direct evidence for a positive role of F-actin in clustering of SVs, but suggest that actin polymer is not sufficient for appropriate localization of SV clusters at presynaptic sites. (jneurosci.org)
  • showing that ATP hydrolysis and release of a phosphate group results in one segment of actin switching from a strand to a helical conformation. (curriki.org)
  • Actin patches are highly motile, they first assemble at sites of polarized cell growth and then move slowly and nondirectionally along the cell cortex. (uniprot.org)
  • They also provided strong evidence that the Rac/Cdc42-specific guanine nucleotide exchange factor (GEF) β-pix localizes to sites of cell-cell contact through a direct interaction with cadherin/β-catenin/scribble, and it promotes SV clustering by increasing actin polymerization at these sites ( Sun and Bamji, 2011 ). (jneurosci.org)
  • Thus, CP appears to cap F-actin barbed ends via the independent interaction of both tentacles with actin. (plos.org)
  • An unmet actin requirement explains the mitotic inhibition of clathrin-mediated endocytosis," eLife , 3:e00829, 2014. (the-scientist.com)
  • This led Royle's team to investigate whether inactive actin was prohibiting endocytosis from occurring. (the-scientist.com)
  • This finding nixed the idea that increased membrane tension alone is responsible for the endocytosis shutdown, and instead led the team to propose that actin availability determines whether endocytosis proceeds. (the-scientist.com)
  • It seems that whether actin is required for endocytosis really depends on how much work the endocytic machinery has to do to create a vesicle," says Royle. (the-scientist.com)
  • Our data support a novel apical recycling model which indicates a critical role for actin patch-mediated endocytosis to maintain polarized growth at the apex. (psu.edu)
  • Actin-propelled invasive membrane protrusions promote fusogenic protein engagement during cell-cell fusion. (nih.gov)
  • Actin is implicated in chemotaxis , phagocytosis , pinocytosis , membrane ruffling , and pretty much anything that requires the shape of a cell to change. (everything2.com)
  • Actin assembly drives the extension of flat membrane protrusions called lamellipodia and finger-like protrusions called filopodia to push the membrane. (hindawi.com)
  • 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). (the-scientist.com)
  • The overall outward-directed movement of the vesicle-actin network is driven by recruitment of vesicles to the plasma membrane in the periphery of the oocyte. (warwick.ac.uk)
  • While other researchers were consumed with showing a direct role for actin in the formation of endocytic vesicles, this study shows that if actin is not available, vesicle budding cannot occur," says Linton Traub, a cell biologist at the University of Pittsburgh who was not involved in the study. (the-scientist.com)