Early activation of p160ROCK by pressure overload in rat heart.
Torsoni, Adriana S., Priscila M. Fonseca, Daniela P Crosara-Alberto, and Kleber G.
Franchini.
Department of Internal Medicine, School of Medicine, State University of Campinas,
13081«hyphen»970 Campinas, SP, Brazil
APStracts 10:0055C, 2003.
We investigated the effects of acute pressure overload on activation of p160ROCK in rat
myocardium. Constriction of transverse aorta, controlled to increase peak systolic
pressure of ascending aorta by ~40 mmHg, induced a rapid association of RhoA with
Dbl-3 and p160ROCK. The binding of p160ROCK to RhoA was rapidly increased,
peaking at 30 min (~3.5-fold), but reduced to lower levels (~1.9-fold) by 60 min of
pressure overload. The activity of immunoprecipitated p160ROCK toward myosin light
chain increased ~2.5-fold within 10 min but decreased to lower levels (~1.6-fold) after 60
min of pressure overload. Confocal microscopic analysis indicated that pressure overload
induced the formation of aggregates of p160ROCK and RhoA along the longitudinal axis
of cardiac myocytes. Immunoelectron microscopic analysis showed that pressure
overload induced the association of p160ROCK and RhoA to Z-line, T-tubule, and
subsarcolemmal areas. The rapid activation of p160ROCK by pressure overload and its
aggregation in subcellular structures involved in transmission of mechanical force
suggest a role for this enzyme in the mechanobiochemical transduction in the
myocardium.
Received 4 March 2002; accepted in final form 23 January 2003
APS Manuscript Number C98-2.
Article publication pending Am J Physiol Cell Physiol
ISSN 1080-4757 Copyright 2003 The American Physiological Society.
Published in APStracts on 25 March 2003