Brief Communication abstract
Nature Cell Biology 4, 312 - 317 (2002)
Published online: 18 March 2002 | doi:10.1038/ncb776
The myosin converter domain modulates muscle performance
Douglas M. Swank1, Aileen F. Knowles2, Jennifer A. Suggs1, Floyd Sarsoza1, Annie Lee1, David W. Maughan3 & Sanford I. Bernstein1
Myosin is the molecular motor that powers muscle contraction as a result of conformational changes during its mechanochemical cycle. We demonstrate that the converter, a compact structural domain that differs in sequence between Drosophila melanogaster myosin isoforms, dramatically influences the kinetic properties of myosin and muscle fibres. Transgenic replacement of the converter in the fast indirect flight muscle with the converter from an embryonic muscle slowed muscle kinetics, forcing a compensatory reduction in wing beat frequency to sustain flight. Conversely, replacing the embryonic converter with the flight muscle converter sped up muscle kinetics and increased maximum power twofold, compared to flight muscles expressing the embryonic myosin isoform. The substitutions also dramatically influenced in vitro actin sliding velocity, suggesting that the converter modulates a rate-limiting step preceding cross-bridge detachment. Our integrative analysis demonstrates that isoform-specific differences in the myosin converter allow different muscle types to meet their specific locomotion demands.
- Department of Biology, Molecular Biology Institute, and the Heart Institute, San Diego State University, San Diego, California 92182–4614, USA
- Department of Chemistry, San Diego State University, San Diego, California 92182-1030, USA
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, Vermont 05405, USA
Correspondence to: Douglas M. Swank1 e-mail: dswank@sciences.sdsu.edu
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