A family of muscle proteins that bind myosin (MyBPs). The most abundant type is MyBPC, which is transversely arrayed in the cross-bridge-bearing (C region) of the A band of the sarcomere in a fixed molar ratio with myosin heavy chains. MyBPC2 (1142 aa) is found in fast skeletal muscle, MyBPC1 in slow muscle. MyBPC3, the cardiac isoform, is expressed exclusively in heart muscle. Protein kinase A-mediated (PKA) phosphorylation of MyBPC3 accelerates the kinetics of cross-bridge cycling and regulates myocyte power output. Mutations are associated with ~15% of cases of familial hypertrophic cardiomyopathy. See obscurin. Myosin-binding protein H (MyBPH, 52 kDa) is found in skeletal muscle in a specific pattern.
Subjects: Medicine and Health — Chemistry.