Alpha-smooth muscle actin (α-SMA)

Alpha-smooth muscle actin (α-SMA) is a specialized actin isoform predominantly expressed in vascular and visceral smooth muscle cells, encoded by the ACTA2 gene. It is a globular structural protein that polymerizes to form filaments (microfilaments), forming a key component of the cytoskeleton and contractile apparatus in muscle cells. In non-muscle cells, notably myofibroblasts, α-SMA expression correlates with increased contractile activity important for wound healing, matrix remodeling, and fibrogenesis. α-SMA is a hallmark marker of myofibroblast activation and is used extensively in research and pathology as a biomarker for fibrosis and tissue repair processes. Mutations in ACTA2 underpin a range of vascular and fibrotic diseases. Although it plays crucial roles in cellular contractility and mechanotransduction, it is not a classical drug target such as a receptor, transporter, or enzyme, but rather serves as a structural marker and effector in disease-related cellular phenotypes.

Other names

ACTA2actin alpha 2alpha-actin-2aortic smooth muscle actinSMactinalpha-SM-actinASMA