Myosin-based regulation of twitch and tetanic contractions in mammalian skeletal muscle

• DOI: 10.7554/elife.68211
• Publication Date: 2021-06-14T12:00:15Z
• Authors: Cameron Hill; Elisabetta Brunello; Luca Fusi; Jesús G Ovejero; Malcolm Irving
• Keywords: Fast twitch muscle

Time-resolved X-ray diffraction of isolated fast-twitch muscles mice was used to show how structural changes in the myosin-containing thick filaments contribute regulation muscle contraction, extending previous focus on by actin-containing thin filaments. This study shows that activation involves following sequence changes: filament activation, disruption helical array myosin motors characteristic resting muscle, release motor domains from folded conformation backbone, and actin attachment. Physiological force generation 'twitch' response skeletal single action potential stimulation is limited incomplete rapid inactivation both Muscle relaxation after repetitive accompanied a complete recovery backbone but reformation array, revealing basis for post-tetanic potentiation muscles.