Dual-filament regulation of relaxation in mammalian fast skeletal muscle.

ABSTRACT: Muscle contraction is driven by myosin motors from the thick filaments pulling on the actin-containing thin filaments of the sarcomere, and it is regulated by structural changes in both filaments. Thin filaments are activated by an increase in intracellular calcium concentration [Ca²⁺]_i and by myosin binding to actin. Thick filaments are activated by direct sensing of the filament load. However, these mechanisms cannot explain muscle relaxation when [Ca²⁺]_i decreases at high load and myosin motors are attached to actin. There is, therefore, a fundamental gap in our understanding of muscle relaxation, despite its importance for muscle function in vivo, for example, for rapid eye movements or, on slower timescales, for the efficient control of post

SUBMITTER: Hill C 

PROVIDER: S-EPMC11929500 | biostudies-literature | 2025 Mar

REPOSITORIES: biostudies-literature