ACTB

This gene encodes one of six different actin proteins. Actins are highly conserved proteins that are involved in cell motility, structure, integrity, and intercellular signaling. The encoded protein is a major constituent of the contractile apparatus and one of the two nonmuscle cytoskeletal actins that are ubiquitously expressed. Mutations in this gene cause Baraitser-Winter syndrome 1, which is characterized by intellectual disability with a distinctive facial appearance in human patients. Numerous pseudogenes of this gene have been identified throughout the human genome. [provided by RefSeq, Aug 2017]

Actin Beta

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.

Adherens junction assembly
Apical protein localization
ATP-dependent chromatin remodeling
Axonogenesis
Cell junction assembly
Cell motility
Cellular response to cytochalasin B
Ephrin receptor signaling pathway
Establishment or maintenance of cell polarity
Fc-gamma receptor signaling pathway involved in phagocytosis
Maintenance of blood-brain barrier
Membrane organization
Morphogenesis of a polarized epithelium
Negative regulation of protein binding
Platelet aggregation
Positive regulation of gene expression, epigenetic
Positive regulation of norepinephrine uptake
Postsynaptic actin cytoskeleton organization
Protein deubiquitination
Protein localization to adherens junction
Regulation of cyclin-dependent protein serine/threonine kinase activity
Regulation of norepinephrine uptake
Regulation of protein localization to plasma membrane
Regulation of transepithelial transport
Regulation of transmembrane transporter activity
Retina homeostasis
Substantia nigra development

Cytoskeleton; Nucleus. Localized in cytoplasmic mRNP granules containing untranslated mRNAs.

Dystonia, juvenile-onset (DJO): A form of dystonia with juvenile onset. Dystonia is defined by the presence of sustained involuntary muscle contraction, often leading to abnormal postures. Patients with juvenile-onset dystonia manifest progressive, generalized, dopa-unresponsive dystonia, developmental malformations and sensory hearing loss.
Baraitser-Winter syndrome 1 (BRWS1): A rare developmental disorder characterized by the combination of congenital ptosis, high-arched eyebrows, hypertelorism, ocular colobomata, and a brain malformation consisting of anterior-predominant lissencephaly. Other typical features include postnatal short stature and microcephaly, intellectual disability, seizures, and hearing loss.

ISGylated.
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.
Monomethylation at Lys-84 (K84me1) regulates actin-myosin interaction and actomyosin-dependent processes. Demethylation by ALKBH4 is required for maintaining actomyosin dynamics supporting normal cleavage furrow ingression during cytokinesis and cell migration.
Methylated at His-73 by SETD3. Methylation at His-73 is required for smooth muscle contraction of the laboring uterus during delivery (By similarity).
N-terminal acetylation by NAA80 affects actin filament depolymerization and elongation, including elongation driven by formins. In contrast, filament nucleation by the Arp2/3 complex is not affected.
(Microbial infection) Monomeric actin is cross-linked by V.cholerae toxins RtxA and VgrG1 in case of infection: bacterial toxins mediate the cross-link between Lys-50 of one monomer and Glu-270 of another actin monomer, resulting in formation of highly toxic actin oligomers that cause cell rounding. The toxin can be highly efficient at very low concentrations by acting on formin homology family proteins: toxic actin oligomers bind with high affinity to formins and adversely affect both nucleation and elongation abilities of formins, causing their potent inhibition in both profilin-dependent and independent manners.