Cardiac myosin ATPase

Cardiac myosin ATPase is an enzyme complex found in cardiac muscle, primarily responsible for converting chemical energy from ATP hydrolysis into the mechanical force required for heart muscle contraction[1][3]. This large, multi-subunit motor protein consists of myosin heavy and light chains arranged to form the thick filaments of the cardiac sarcomere. The ATPase activity resides in the myosin head (S1 fragment), where ATP binding, hydrolysis, and subsequent interactions with actin filaments drive the cyclic power strokes of contraction[1][3]. Regulation occurs via structural proteins (e.g., cardiac myosin binding protein C), phosphorylation state, and allosteric modulation by drugs. Pathogenic mutations in the β-cardiac myosin heavy chain gene (MYH7) or MYH6 can alter ATPase function, underlie various hereditary cardiomyopathies, and serve as actionable targets for modulating cardiac contractility in heart failure and hypertrophic cardiomyopathy treatments[1][4][6]. Drugs such as mavacamten (inhibitor) and omecamtiv mecarbil (activator) target cardiac myosin ATPase activity to therapeutically adjust myocardial contractility[4][6].

Other names

Cardiac myosinβ-cardiac myosinCardiac myosin heavy chain ATPaseMYH7 ATPase (referring to the β-cardiac isoform)Cardiac muscle myosin ATPaseMyosin ATPase (cardiac isoform)

Myosin ATPase inhibitors (e.g., mavacamten): reduce myosin-actin interactions and contractility by stabilizing the off-state/inhibited conformation of the myosin heads Myosin ATPase activators (e.g., omecamtiv mecarbil): increase contractile force by enhancing myosin-actin cycling and/or increasing the proportion of myosin heads in the on-state ready to generate force