Myosin heavy chain (MHC)

The **myosin heavy chain** (MHC) is the principal polypeptide component of the myosin molecular motor, a large ATP-dependent protein complex that drives muscle contraction and various actin-based cellular movements[1][3][5]. Each myosin II molecule consists of two heavy chains and four light chains, with the heavy chains conferring ATPase activity and mediating actin binding and movement through their head, neck, and tail domains[1][3]. MHC isoforms are encoded by a multigene family (e.g., MYH7 for beta-myosin heavy chain in cardiac and type I skeletal muscle)[2][5][6]. They are fundamental for the formation of thick muscle filaments, which interact with actin in the sarcomere to produce contraction in both skeletal and cardiac muscle. Different isoforms are expressed in specialized muscle types, defining their contractile properties. Mutations in myosin heavy chain genes are implicated in inherited cardiomyopathies and muscle disorders[2][5][6]. However, the MHC is not a classic therapeutic target like a receptor or enzyme inhibitor in clinical practice; direct pharmacological targeting carries high risk due to its essential physiological roles[1][2][5].

Other names

Myosin II heavy chainBeta-myosin heavy chainβ-myosin heavy chainMyosin heavy chain isoforms

Inhibitors or modulators (mainly in experimental/research use) act by blocking ATPase activity or myosin-actin interaction, thereby affecting muscle contractility.