ACTA2: Actin Alpha 2, Smooth Muscle
Key regulator of smooth muscle contraction and vascular integrity; mutations linked to aortic aneurysms and multisystemic smooth muscle dysfunction.
Gene Information Card
| Symbol | ACTA2 |
|---|---|
| Full Name | Actin Alpha 2, Smooth Muscle |
| Gene Type | Protein coding |
| Chromosomal Location | 10q23.31 |
| NCBI Gene ID | 59 ncbi.nlm.nih.gov/gene/59 |
| Ensembl ID | ENSG00000107796 |
| UniProt ID | P62736 |
| OMIM ID | 102620 |
| HGNC ID | 130 |
| Aliases | ACTSA, ACTVS, alpha-actin-2, smooth muscle alpha-actin |
Description
ACTA2 encodes alpha-actin-2, a major component of the contractile apparatus in smooth muscle cells. This protein is essential for vascular smooth muscle contraction and maintenance of arterial integrity. Mutations in ACTA2 are a common cause of familial thoracic aortic aneurysms and dissections (TAAD) and are associated with multisystemic smooth muscle dysfunction syndrome (MSMDS).
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Thoracic Aortic Aneurysm and Dissection (TAAD) | Missense mutations disrupt actin polymerization and contractile function, weakening the aortic wall. | ClinVar, OMIM |
| Multisystemic Smooth Muscle Dysfunction Syndrome (MSMDS) | Loss-of-function or dominant-negative mutations impair smooth muscle contraction in multiple organs, leading to vascular, gastrointestinal, and pulmonary complications. | OMIM, NCBI |
| Moyamoya Disease | Specific ACTA2 mutations (e.g., p.Arg179His) predispose to cerebrovascular occlusive disease. | ClinVar, OMIM |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Artery | 124.5 | High |
| Uterus | 78.3 | High |
| Stomach | 65.2 | High |
| Bladder | 52.1 | High |
| Lung | 12.4 | Medium |
| Heart | 8.9 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| Aortic Smooth Muscle Cells | 145.2 | Primary cell type |
| Uterine Smooth Muscle Cells | 88.7 | High expression |
| Bronchial Smooth Muscle Cells | 42.3 | Moderate expression |
| HEK293 | 1.2 | Low expression (non-muscle) |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.731G>A (p.Arg244His) | Missense | Common in TAAD | Disrupts actin filament stability |
| c.536G>A (p.Arg179His) | Missense | Associated with Moyamoya | Alters actin polymerization dynamics |
| c.445C>T (p.Arg149Cys) | Missense | Rare | Impairs smooth muscle contraction |
| c.1A>G (p.Met1?) | Start loss | Very rare | Complete loss of protein function |
Mutation functional classification
Loss of Function (LOF)
Start-loss or nonsense mutations that abolish protein production, leading to haploinsufficiency.
Gain of Function (GOF)
Not typically described; most mutations are dominant-negative or loss-of-function.
Dominant Negative (DN)
Missense mutations (e.g., p.Arg244His, p.Arg179His) that produce defective actin monomers, interfering with filament assembly and contractile function.
View complete mutation data：
Gene Ontology (GO)
| • GO:0005524 - ATP binding | • GO:0005200 - structural constituent of cytoskeleton |
| • GO:0006936 - muscle contraction | • GO:0015629 - actin cytoskeleton |
| • GO:0030049 - muscle filament sliding | • GO:0043231 - intracellular membrane-bounded organelle |
Pathways
• Smooth Muscle Contraction (Reactome: R-HSA-445355)
• Actin Cytoskeleton Regulation (KEGG: hsa04810)
• Vascular Smooth Muscle Contraction (KEGG: hsa04270)
Protein Summary
Alpha-actin-2 (UniProt P62736) is a 42 kDa protein composed of 377 amino acids. It forms the core of thin filaments in smooth muscle cells, providing structural support and enabling contraction via interaction with myosin. The protein is highly conserved and expressed predominantly in vascular and visceral smooth muscle. Mutations in ACTA2 compromise filament integrity, leading to vascular fragility and multisystemic smooth muscle dysfunction.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| ACTA2 Knockout HEK293 Cell Line | EDJ-KQ1463 | Human | 59 | Details Get a Quote |
| ACTA2 Knockout HCT 116 Cell Line | EDJ-KQ21027 | Human | 59 | Details Get a Quote |
| ACTA2 Knockout HeLa Cell Line | EDJ-KQ21028 | Human | 59 | Details Get a Quote |
| ACTA2 Knockout A-549 Cell Line | EDJ-KQ19690 | Human | 59 | Details Get a Quote |
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