Calponin

Calponin is an-actin binding protein that is involved in regulation of smooth muscle contraction and cytoskeletal establishment. Calponin was first identified in smooth muscle from chicken gizzard which was later characterized as an actin associated filament protein with around 300 amino acids. Calponin functions as a calcium binding protein that inhibits ATPase activity of myosin in smooth muscle. Phosphorylation of calponin by a protein kinase releases this inhibition of the smooth muscle ATPase, which is depended on calcium binding calmodulin. cDNA cloning has determined many isoforms of calponin including calponin 1, calponin 2, and calponin 3. Which has left to many studies of calponin 1 in smooth muscles. Calponin adjusts actomyosin ATPase activity and creates an influence in the production of contractile force in smooth muscle cells. Although it has much involvement in smooth muscle tissue, calponin is also involved in cellular signaling pathways related to calcium and ERK activation.