X-ray diffraction evidence for myosin-troponin connections and tropomyosin movement during stretch activation of insect flight muscle.

ABSTRACT: Stretch activation is important in the mechanical properties of vertebrate cardiac muscle and essential to the flight muscles of most insects. Despite decades of investigation, the underlying molecular mechanism of stretch activation is unknown. We investigated the role of recently observed connections between myosin and troponin, called "troponin bridges," by analyzing real-time X-ray diffraction "movies" from sinusoidally stretch-activated Lethocerus muscles. Observed changes in X-ray reflections arising from myosin heads, actin filaments, troponin, and tropomyosin were consistent with the hypothesis that troponin bridges are the key agent of mechanical signal transduction. The time-resolved sequence of molecular changes suggests a mechanism for stretch activation, in which troponin brid

SUBMITTER: Perz-Edwards RJ 

PROVIDER: S-EPMC3017141 | biostudies-literature | 2011 Jan

REPOSITORIES: biostudies-literature