The force of the myosin motor sets cooperativity in thin filament activation of skeletal muscles.

ABSTRACT: Contraction of striated muscle is regulated by a dual mechanism involving both thin, actin-containing filament and thick, myosin-containing filament. Thin filament is activated by Ca²⁺ binding to troponin, leading to tropomyosin displacement that exposes actin sites for interaction with myosin motors, extending from the neighbouring stress-activated thick filaments. Motor attachment to actin contributes to spreading activation along the thin filament, through a cooperative mechanism, still unclear, that determines the slope of the sigmoidal relation between isometric force and pCa (-log[Ca²⁺]), estimated by Hill coefficient n_H. We use sarcomere-level mechanics in demembranated fibres of rabbit skeletal muscle activated by Ca²⁺ at different temper

SUBMITTER: Caremani M 

PROVIDER: S-EPMC9674696 | biostudies-literature | 2022 Nov

REPOSITORIES: biostudies-literature