Myosin Binding Protein C in the Heart

Abstract

Yocardial force generation is initiated on the re- lease of calcium ions from the sarcoplasmic retic- ulum and subsequent activation of the contractile apparatus.1 A schematic of the cardiac sarcomere and some of its component proteins is shown in the Figure.2 Contractile activation involves binding calcium to Tn-C, redistribution of the affinity of Tn-I for Tn-C away from Tn-T, and movement of tropomyosin on the thin filament, thereby exposing bind- ing sites on actin. Binding of the myosin S1 domain to actin leads to cross-bridge force development. However, this sim- ple two state model of muscle contraction is not sufficient to explain many features of muscle contraction.2 For example,