ACTG2
Function
Actins are highly conserved proteins that are involved in various types of cell motility and are ubiquitously expressed in all eukaryotic cells.
Involvement in disease
Visceral myopathy 1
VSCM1
An autosomal dominant form of myopathic pseudo-obstruction characterized by impaired function of enteric smooth muscle cells, resulting in abnormal intestinal motility, severe abdominal pain, malnutrition, and even death. The disease shows inter- and intrafamilial variability. Most severely affected patients exhibit prenatal bladder enlargement, intestinal malrotation, neonatal functional gastrointestinal obstruction, and dependence on total parenteral nutrition and urinary catheterization.
None
The disease is caused by variants affecting the gene represented in this entry.
Megacystis-microcolon-intestinal hypoperistalsis syndrome 5
MMIHS5
A form of megacystis-microcolon-intestinal hypoperistalsis syndrome, a congenital visceral myopathy primarily affecting females, and characterized by loss of smooth muscle contraction in the bladder and intestine. Affected individuals present at birth with functional obstruction of intestine, microcolon, dilation of bladder, and secondary hydronephrosis. The majority of cases have a fatal outcome due to malnutrition and sepsis, followed by multiorgan failure. MMIHS5 is an autosomal dominant form with significant inter- and intrafamilial variability.
None
The disease is caused by variants affecting the gene represented in this entry.
Post-translational modifications
Oxidation of Met-45 and Met-48 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 promotes actin repolymerization.
Actin, gamma-enteric smooth muscle, intermediate form
N-terminal cleavage of acetylated cysteine of intermediate muscle actin by ACTMAP.
Monomethylation at Lys-85 (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-74 by SETD3.
(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-51 of one monomer and Glu-271 of another actin monomer, resulting in formation of highly toxic actin oligomers that cause cell rounding (PubMed:19015515). 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 (PubMed:26228148).
Sequence Similarities
Belongs to the actin family.
Tissue Specificity
In the intestine, abundantly expressed in smooth muscle cells of muscularis mucosa and muscularis propria. Also detected in intestinal vascular smooth muscle cells.
Cellular localization
- Cytoplasm
- Cytoskeleton
Alternative names
ACTA3, ACTL3, ACTSG, ACTG2, Alpha-actin-3, Gamma-2-actin, Smooth muscle gamma-actin