HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 295/4/C994    most recent 00318.2008v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (4) Citing Articles via Google Scholar Google Scholar Articles by Goeckeler, Z. M. Articles by Wysolmerski, R. B. Search for Related Content PubMed PubMed Citation Articles by Goeckeler, Z. M. Articles by Wysolmerski, R. B.

VASCULAR BIOLOGY

Nonmuscle myosin II is responsible for maintaining endothelial cell basal tone and stress fiber integrity

¹Department of Neurobiology and Anatomy and ²The Mary Babb Randolph Cancer Center, West Virginia University School of Medicine, Morgantown, West Virginia; and ³Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, Missouri

Submitted 13 June 2008 ; accepted in final form 11 August 2008

Cultured confluent endothelial cells exhibit stable basal isometric tone associated with constitutive myosin II regulatory light chain (RLC) phosphorylation. Thrombin treatment causes a rapid increase in isometric tension concomitant with myosin II RLC phosphorylation, actin polymerization, and stress fiber reorganization while inhibitors of myosin light chain kinase (MLCK) and Rho-kinase prevent these responses. These findings suggest a central role for myosin II in the regulation of endothelial cell tension. The present studies examine the effects of blebbistatin, a specific inhibitor of myosin II activity, on basal tone and thrombin-induced tension development. Although blebbistatin treatment abolished basal tension, this was accompanied by an increase in myosin II RLC phosphorylation. The increase in RLC phosphorylation was Ca²⁺ dependent and mediated by MLCK. Similarly, blebbistatin inhibited thrombin-induced tension without interfering with the increase in RLC phosphorylation or in F-actin polymerization. Blebbistatin did prevent myosin II filament incorporation and association with polymerizing or reorganized actin filaments leading to the disappearance of stress fibers. Thus the inhibitory effects of blebbistatin on basal tone and induced tension are consistent with a requirement for myosin II activity to maintain stress fiber integrity.

actin; blebbistatin; isometric tension; myosin light chain kinase; regulatory light chain phosphorylation; focal adhesions

This article has been cited by other articles:

				V. Dugina, I. Zwaenepoel, G. Gabbiani, S. Clement, and C. Chaponnier {beta}- and {gamma}-cytoplasmic actins display distinct distribution and functional diversity J. Cell Sci., August 15, 2009; 122(16): 2980 - 2988. [Abstract] [Full Text] [PDF]

				J. A. Brown, R. B. Wysolmerski, and P. C. Bridgman Dorsal Root Ganglion Neurons React to Semaphorin 3A Application through a Biphasic Response that Requires Multiple Myosin II Isoforms Mol. Biol. Cell, February 1, 2009; 20(4): 1167 - 1179. [Abstract] [Full Text] [PDF]