Actin Alpha 2, Smooth Muscle (ACTa2)

Actin, aortic smooth muscle is one of six different actin isoforms which have been identified. Six different actin isoforms have been identified in vertebrates by amino acid sequencing: skeletal muscle, cardiac muscle, 2 smooth muscle (enteric and aortic), and 2 cytoplasmic (beta and gamma) (Vandekerckhove and Weber, 1979). Their amino acid sequences are similar and well conserved in evolution; e.g., skeletal and cardiac actins differ by only 4 amino acids, and skeletal muscle and cytoplasmic beta-actins differ by only 25 amino acids out of a total of 374.Ueyama et al. (1984) isolated and characterized the human aortic smooth muscle actin gene. The gene has a transition point mutation in position 309, substituting thymine for cytosine.