Actins are highly conserved proteins involved in cell motility, structure and integrity. Actin has been found to be expressed in at least six isomeric forms. It is expressed in heart and skeletal striated muscle tissue, and in certain smooth muscle tissues, regulating contractile potentials for these cells. It is also expressed in the cytoplasm of non-muscle cells, functioning to control cell structure and motility. Smooth muscle alpha actin is of further interest because it is one of a few genes whose expression is relatively restricted to vascular smooth muscle cells. Expression of smooth muscle alpha actin is regulated by hormones, cell proliferation, and altered by pathological conditions including oncogenic transformation and atherosclerosis.
