Cooling intact and demembranated trabeculae from rat heart releases myosin motors from their inhibited conformation.

ABSTRACT: Myosin filament-based regulation supplements actin filament-based regulation to control the strength and speed of contraction in heart muscle. In diastole, myosin motors form a folded helical array that inhibits actin interaction; during contraction, they are released from that array. A similar structural transition has been observed in mammalian skeletal muscle, in which cooling below physiological temperature has been shown to reproduce some of the structural features of the activation of myosin filaments during active contraction. Here, we used small-angle x-ray diffraction to characterize the structural changes in the myosin filaments associated with cooling of resting and relaxed trabeculae from the right ventricle of rat hearts from 39°C to 7°C. In intact quiescent trabeculae, coolin

SUBMITTER: Ovejero JG 

PROVIDER: S-EPMC8823665 | biostudies-literature | 2022 Mar

REPOSITORIES: biostudies-literature