ACTA2 (actin alpha 2) is an
actin
Actin is a family of globular multi-functional proteins that form microfilaments in the cytoskeleton, and the thin filaments in muscle fibrils. It is found in essentially all eukaryotic cells, where it may be present at a concentration of ...
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...
with several aliases including alpha-actin, alpha-actin-2, aortic smooth muscle or alpha smooth muscle actin (α-SMA, SMactin, alpha-SM-actin, ASMA).
Actin
Actin is a family of globular multi-functional proteins that form microfilaments in the cytoskeleton, and the thin filaments in muscle fibrils. It is found in essentially all eukaryotic cells, where it may be present at a concentration of ...
s are a
family
Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...
of
globular
A globular cluster is a spheroidal conglomeration of stars that is bound together by gravity, with a higher concentration of stars towards its center. It can contain anywhere from tens of thousands to many millions of member stars, all orbiting ...
multi-functional
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...
s that form
microfilament
Microfilaments, also called actin filaments, are protein filaments in the cytoplasm of eukaryotic cells that form part of the cytoskeleton. They are primarily composed of polymers of actin, but are modified by and interact with numerous other ...
s. ACTA2 is one of 6 different actin
isoforms
A protein isoform, or "protein variant", is a member of a set of highly similar proteins that originate from a single gene and are the result of genetic differences. While many perform the same or similar biological roles, some isoforms have uniqu ...
and is involved in the
contractile apparatus of
smooth muscle
Smooth muscle is one of the three major types of vertebrate muscle tissue, the others being skeletal and cardiac muscle. It can also be found in invertebrates and is controlled by the autonomic nervous system. It is non- striated, so-called bec ...
. ACTA2 (as with all the actins) is extremely
highly conserved and found in nearly all mammals.
In humans, ACTA2 is encoded by the ''ACTA2''
gene
In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...
located on 10q22-q24.
Mutations in this gene cause a variety of vascular diseases, such as
thoracic aortic disease,
coronary artery disease
Coronary artery disease (CAD), also called coronary heart disease (CHD), or ischemic heart disease (IHD), is a type of cardiovascular disease, heart disease involving Ischemia, the reduction of blood flow to the cardiac muscle due to a build-up ...
,
stroke
Stroke is a medical condition in which poor cerebral circulation, blood flow to a part of the brain causes cell death. There are two main types of stroke: brain ischemia, ischemic, due to lack of blood flow, and intracranial hemorrhage, hemor ...
,
Moyamoya disease
Moyamoya disease is a disease in which certain arteries in the brain are constricted. Blood flow is blocked by constriction and blood clots (thrombosis). A collateral circulation develops around the blocked vessels to compensate for the blockage, ...
, and
multisystemic smooth muscle dysfunction syndrome.
ACTA2 (commonly referred to as alpha-smooth muscle actin or α-SMA) is often used as a marker of
myofibroblast
A myofibroblast is a cell phenotype that was first described as being in a state between a fibroblast and a smooth muscle cell.
Structure
Myofibroblasts are contractile web-like fusiform cells that are identifiable by their expression of α-s ...
formation.
Studies have shown that ACTA2 is associated with
TGF-β pathway that enhances contractile properties of
hepatic stellate cell
Hepatic stellate cells (HSC), also known as perisinusoidal cells or Ito cells (earlier ''lipocytes'' or ''fat-storing cells''), are pericytes found in the perisinusoidal space of the liver, also known as the space of Disse (a small area between ...
s leading to
liver fibrosis and cirrhosis.
References
Further reading
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External links
GeneReviews/NIH/NCBI/UW entry on Thoracic Aortic Aneurysms and Aortic Dissections*
Human proteins
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