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Troponin-Tropomyosin Control of Thin Filament Activity Revealed by Electron Microscopy and 3-D Reconstruction.

Published online by Cambridge University Press:  02 July 2020

W. Lehman ,
V. Hatch ,
M. Rosol ,
V. Korman ,
R. Horowitz ,
J. Van Eyk ,
L. S. Tobacman  and
R. Craig
W. Lehman
Affiliation:
Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA02118
V. Hatch
Affiliation:
Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA02118
M. Rosol
Affiliation:
Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA02118
V. Korman
Affiliation:
Departments of Biochemistry and Internal Medicine, University of Iowa College of Medicine, Iowa City, IA52242
R. Horowitz
Affiliation:
Department of Cell Biology, University of Massachusetts Medical School, Worcester, MA01655
J. Van Eyk
Affiliation:
Department of Physiology, Queen's University, Kingston, Ontario.
L. S. Tobacman
Affiliation:
Departments of Biochemistry and Internal Medicine, University of Iowa College of Medicine, Iowa City, IA52242
R. Craig
Affiliation:
Department of Cell Biology, University of Massachusetts Medical School, Worcester, MA01655
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Extract

Muscle contraction and the actomyosin ATPase that drives the contractile process are switched on and off by changes in sarcoplasmic free Ca2+ -concentration. In skeletal and cardiac muscles, on-off switching is mediated by the actinassociated protein tropomyosin and by the troponin complex. While the details of this mechanism are still subject to debate, it is well-accepted that tropomyosin strands move to sterically block and unblock myosin binding sites on actin, thereby controlling actomyosin ATPase and consequently contraction. It is also well known that the Ca2+- dependency of the movement of tropomyosin on actin is governed by troponin.

As a means of studying tropomyosin movement and the influence of troponin, we have used cryo-EM, negative staining and 3-dimensional helical reconstruction to define the positions of tropomyosin and troponin on thin filaments. We examined various preparations of native isolated filaments and filaments reconstituted with wild-type and mutant proteins.

Type
Philadelphia—The Other Motor City: Muscle and Non-Muscle Motility. A Dedication to Dr. Lee Peachey
Information
Microscopy and Microanalysis , Volume 6 , Issue S2: Proceedings: Microscopy & Microanalysis 2000, Microscopy Society of America 58th Annual Meeting, Microbeam Analysis Society 34th Annual Meeting, Microscopical Society of Canada/Societe de Microscopie de Canada 27th Annual Meeting, Philadelphia, Pennsylvania August 13-17, 2000 , August 2000 , pp. 88 - 89
Copyright
Copyright © Microscopy Society of America

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References

References:

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