| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Pathology, Saint Louis University, St. Louis, Missouri, USA
2 Biochemistry & Molecular Biophysics, Washington University, St. Louis, Missouri, USA
3 Physiology, Indiana University, Indianapolis, Indiana, USA
* To whom correspondence should be addressed. E-mail: wysolmer{at}slucare1.sluh.edu.
Thus far determining the relative contribution of Ca2+/calmodulin dependent myosin light chain kinase (MLCK) and Ca2+-independent Rho-kinase pathways to myosin II activation and contraction has been difficult. In this study, we characterize the role of Rho-kinase in a rat embryo fibroblast cell line (REF-52), which contains no detectable MLCK. No endogenous MLCK could be detected in REF-52 cells by either western or northern blot analysis. In the presence or absence of Ca2+, thrombin or lysophosphatidic acid (LPA) increased RhoA activity and Rho-kinase activity, correlating with isometric tension development and myosin II regulatory light chain (RLC) phosphorylation. Resting tension is associated with a basal phosphorylation of 0.31 [[plusm]]0.02 mol PO4/mol RLC while upon LPA or thrombin treatment myosin II RLC phosphorylation increases to 1.08 [[plusm]]0.05 and 0.82 [[plusm]]0.05 mol PO4/mol RLC, respectively, within 2.5 minutes. Ca2+ chelation has minimal effect on the kinetics and magnitude of isometric tension development and RLC phosphorylation. Treatment of REF-52 cells with the Rho-kinase specific inhibitor Y-27632 abolished thrombin and LPA stimulated contraction and RLC phosphorylation. These results suggest that Rho-kinase is sufficient to activate myosin II motor activity and contraction in REF-52 cells.
This article has been cited by other articles:
|
|
 |
|
  L. Follonier, S. Schaub, J.-J. Meister, and B. Hinz Myofibroblast communication is controlled by intercellular mechanical coupling J. Cell Sci., October 15, 2008; 121(20): 3305 - 3316. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Z. M. Goeckeler, P. C. Bridgman, and R. B. Wysolmerski Nonmuscle myosin II is responsible for maintaining endothelial cell basal tone and stress fiber integrity Am J Physiol Cell Physiol, October 1, 2008; 295(4): C994 - C1006. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L. Nordquist, E. Y. Lai, M. Sjoquist, A. Patzak, and A. E. G. Persson Proinsulin C-peptide constricts glomerular afferent arterioles in diabetic mice. A potential renoprotective mechanism Am J Physiol Regulatory Integrative Comp Physiol, March 1, 2008; 294(3): R836 - R841. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Maeda, Y.-i. Ozaki, S. Sivakumaran, T. Akiyama, H. Urakubo, A. Usami, M. Sato, K. Kaibuchi, and S. Kuroda Ca-independent phospholipase A2-dependent sustained Rho-kinase activation exhibits all-or-none response. Genes Cells, September 1, 2006; 11(9): 1071 - 1083. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
F. Yin, A. M. Hoggatt, J. Zhou, and B. P. Herring 130-kDa smooth muscle myosin light chain kinase is transcribed from a CArG-dependent, internal promoter within the mouse mylk gene Am J Physiol Cell Physiol, June 1, 2006; 290(6): C1599 - C1609. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. Szaszi, G. Sirokmany, C. D. Ciano-Oliveira, O. D. Rotstein, and A. Kapus Depolarization induces Rho-Rho kinase-mediated myosin light chain phosphorylation in kidney tubular cells Am J Physiol Cell Physiol, September 1, 2005; 289(3): C673 - C685. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
| Visit Other APS Journals Online |
