MYOCD (myocardin) is a muscle-restricted transcriptional coactivator that functions as a critical regulator of cardiac and smooth muscle cell differentiation. MYOCD acts as a cofactor of serum response factor (SRF), binding to CArG box DNA sequences to modulate transcription of muscle-specific genes 1. In cardiogenesis, MYOCD works synergistically with TBX5 and GATA4 to activate cardiac gene programs, with the three-factor combination most effectively inducing cardiac marker expression while suppressing non-cardiac genes 1. MYOCD promotes vascular smooth muscle cell (VSMC) contractile differentiation and inhibits pathological phenotypic switching; RBPMS enhances MYOCD alternative splicing to promote the contractile VSMC phenotype and reduce atherosclerotic plaque development 2. In airway smooth muscle, the RhoA/ROCK-MYOCD pathway regulates cell proliferation and differentiation during abnormal airway remodeling 3. MYOCD enables direct reprogramming of human urine cells and fibroblasts into cardiomyocyte-like cells through chr17 remodeling 4. Disease relevance includes congenital megabladder 5 and involvement in pathological processes: MYOCD promotes TGF-β-induced epithelial-mesenchymal transition and metastasis in lung cancer through positive feedback with SMAD3/SMAD4 6, and MYOCD amplification occurs in uterine leiomyosarcomas 7. PRMT5-mediated disruption of MYOCD-SRF interaction accelerates neointimal hyperplasia 8.