Myocardin (MYOCD)

Myocardin is a smooth muscle and cardiac muscle-specific transcriptional coactivator of serum response factor. When expressed ectopically in nonmuscle cells, myocardin can induce smooth muscle differentiation by its association with serum response factor. The 807-amino acid mouse myocardin protein belongs to the SAP domain family of nuclear proteins, which regulate diverse aspects of chromatin remodeling and transcription. Myocardin activates cardiac muscle promoters by associating with SRF. Expression of a dominant-negative mutant of myocardin in Xenopus embryos interfered with myocardial cell differentiation. The authors concluded that myocardin is the founding member of a class of muscle transcription factors and provides a mechanism whereby SRF can convey myogenic activity to cardiac muscle genes.