Hostname: page-component-586b7cd67f-g8jcs Total loading time: 0 Render date: 2024-11-28T07:25:07.943Z Has data issue: false hasContentIssue false
  • English
  • Français

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
Get access

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

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

References:

1.Lehman, W., et al., 1994. Ca2+-induced tropomyosin movement in Limulus thin filaments revealed by threedimensional reconstruction. Nature 268: 65–67.CrossRefGoogle Scholar
2.Lehman, W., et al., 1995. Steric-blocking by tropomyosin visualized in relaxed vertebrate muscle thin filaments. J. Mol. Biol. 251:191–196.CrossRefGoogle ScholarPubMed
3.Xu, C., et al., 1999. Tropomyosin positions in regulated thin filaments revealed by cryoelectron microscopy. Biophys. J. 77:985–992.CrossRefGoogle ScholarPubMed
4.Vibert, P., et al., 1997. Steric-model for activation of muscle thin filaments. J. Mol. Biol. 266:8–14.CrossRefGoogle ScholarPubMed
5.Landis, C. A., et al., 1997. The active state of the thin filaments destabilized by an internal deletion in tropomyosin. J. Biol. Chem. 272:14051–14056.CrossRefGoogle ScholarPubMed
6.Rosol, M., et al., 2000. Three-dimensional reconstruction of thin filaments containing mutant tropomyosin. Biophys. J. 78:918–926.CrossRefGoogle ScholarPubMed
7.Lehman, W. et al., 2000. Tropomyosin control of thin filament activity revealed by electron microscopy and 3-D reconstruction. Biophys. J. 78:399a.Google Scholar
8.Rosol, M. et al., 2000. Troponin density detected on thin filaments by electron microscopy and 3-D reconstruction. Biophys. J. 78:399a.Google Scholar