Calponin (CALP)

Calponin is a 34 kD polypeptide that interacts with actin, tropomyosin, and calmodulin. It is involved in smooth muscle contraction mechanism and is restricted exclusively to smooth muscle tissue. Anti-calponin has been found to be useful in differentiating benign sclerosing lesions of the breast from carcinoma. Calponin positivity has also been noted in malignant myoepithelioma and pleomorphic adenoma of salivary gland origin, as well as angiomatoid malignant fibrous histiocytoma.