Mothers against decapentaplegic homolog 4 (SMAD4)

In muscle structure, plays a central role in the equilibrium between atrophy and hypertrophy. MSTN reduction causes SMAD4 discharge and subsequent recruitment by the BMP pathway to promote hypertrophy through phosphorylated SMAD1/5/8.

Acts synergistically with SMAD1 and YY1 in bone morphogenetic protein (BMP)-mediated cardiac-specific gene expression. Binds to SMAD binding elements (SBEs) (5'-GTCT/AGAC-3') within BMP response element (BMPRE) of cardiac activating regions (By similarity).