UniProt ID: Q7ZVI7 |
FUNCTION: Actin is a highly conserved protein that polymerizes to produce filaments that form cross-linked networks in the cytoplasm of cells. Actin exists in both monomeric (G-actin) and polymeric (F-actin) forms, both forms playing key functions, such as cell motility and contraction. In addition to their role in the cytoplasmic cytoskeleton, G- and F-actin also localize in the nucleus, and regulate gene transcription and motility and repair of damaged DNA. {ECO:0000250|UniProtKB:P60709}. CATALYTIC ACTIVITY: Reaction=ATP + H2O = ADP + H(+) + phosphate; Xref=Rhea:RHEA:13065, ChEBI:CHEBI:15377, ChEBI:CHEBI:15378, ChEBI:CHEBI:30616, ChEBI:CHEBI:43474, ChEBI:CHEBI:456216; Evidence={ECO:0000250|UniProtKB:P68137}; SUBUNIT: Polymerization of globular actin (G-actin) leads to a structural filament (F-actin) in the form of a two-stranded helix (By similarity). Each actin can bind to 4 others (By similarity). {ECO:0000250|UniProtKB:P60709, ECO:0000250|UniProtKB:P60710}. SUBCELLULAR LOCATION: Cytoplasm, cytoskeleton {ECO:0000250|UniProtKB:P60710}. Nucleus {ECO:0000250|UniProtKB:O93400}. TISSUE SPECIFICITY: Skeletal muscle, heart, gill, digestive tissue and brain (PubMed:9987040). Widespread expression throughout the brain, with highest levels in regions where neuronal proliferation is greatest (PubMed:9987040). {ECO:0000269|PubMed:9987040}. PTM: [Actin, cytoplasmic 1]: N-terminal cleavage of acetylated methionine of immature cytoplasmic actin by ACTMAP. {ECO:0000250|UniProtKB:P60709}. PTM: Oxidation of Met-44 and Met-47 by MICALs (mical1, mical2 or mical3) to form methionine sulfoxide promotes actin filament depolymerization. Mical1 and mical2 produce the (R)-S-oxide form. The (R)-S-oxide form is reverted by msrb1 and msrb2, which promote actin repolymerization (By similarity). {ECO:0000250|UniProtKB:P60710}. PTM: Methylation at His-73 by SETD3. Methylation stabilizes actin filaments. {ECO:0000250|UniProtKB:P60706}. MISCELLANEOUS: In vertebrates 3 main groups of actin isoforms, alpha, beta and gamma have been identified. The alpha actins are found in muscle tissues and are a major constituent of the contractile apparatus. The beta and gamma actins coexist in most cell types as components of the cytoskeleton and as mediators of internal cell motility. {ECO:0000250|UniProtKB:O93400}. SIMILARITY: Belongs to the actin family. {ECO:0000305}. |
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