Am J Physiol Cell Physiol Fuel your research with LabChart
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Am J Physiol Cell Physiol 255: C34-C42, 1988;
0363-6143/88 $5.00
This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Tanner, J. A.
Right arrow Articles by Meiss, R. A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Tanner, J. A.
Right arrow Articles by Meiss, R. A.

AJP - Cell Physiology, Vol 255, Issue 1 C34-C42, Copyright © 1988 by American Physiological Society

ARTICLES

Regulation of glycerinated smooth muscle contraction and relaxation by myosin phosphorylation

J. A. Tanner, J. R. Haeberle and R. A. Meiss
Department of Physiology and Biophysics of Medicine, Indiana University School of Medicine, Indianapolis 46223.

Regulation of isometric force maintenance, isotonic shortening velocity, and muscle stiffness by myosin phosphorylation was examined during both contraction and relaxation of chemically permeabilized (glycerinated) rat uterine smooth muscle. Phosphorylation of the 20,000-Da light chain of myosin (LC20) was manipulated by varying the calcium activity of the bathing solution or by thiophosphorylation of LC20 in the presence of ATP gamma S. With saturating calcium and calmodulin, LC20 phosphorylation was 0.43 mol PO4/mol LC20. This increased to 0.92-0.96 mol PO4/mol LC20 on addition of ATP gamma S. Over the entire range of phosphorylation, there was a significant (P less than 0.001) linear correlation between force and phosphorylation. Stiffness increased monotonically with increasing force; however, the relationship was nonlinear, with stiffness increasing faster at lower levels of activation. Force, stiffness, shortening velocity, and LC20 phosphorylation were compared at identical calcium activities during steady-state conditions of partial contraction and partial relaxation. The ratio of the value of each parameter measured during relaxation to that measured during contraction was 1.11 for force, 1.09 for stiffness, 1.01 for shortening velocity, and 0.83 for LC20 phosphorylation. These results support the hypothesis that contraction and relaxation in glycerinated rat uterine muscle are regulated primarily by phosphorylation and dephosphorylation of LC20.


This article has been cited by other articles:


Home page
 Am. J. Physiol. Cell Physiol.Home page
C. M. Rembold, R. L. Wardle, C. J. Wingard, T. W. Batts, E. F. Etter, and R. A. Murphy
Cooperative attachment of cross bridges predicts regulation of smooth muscle force by myosin phosphorylation
Am J Physiol Cell Physiol, September 1, 2004; 287(3): C594 - C602.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online