title: Activation of Rho-associated coiled-coil protein kinase 1 (ROCK-1) by caspase-3 cleavage plays an essential role in cardiac myocyte apoptosis.
abstract: Rho-associated coiled-coil protein kinase 1 (ROCK-1) is a direct cleavage substrate of activated caspase-3, which is associated with heart failure. In the course of human heart failure, we found marked cleavage of ROCK-1 resulting in a 130-kDa subspecies, which was absent in normal hearts and in an equivalent cohort of patients with left ventricular assist devices. Murine cardiomyocytes treated with doxorubicin led to enhanced ROCK-1 cleavage and apoptosis, all of which was blocked by a caspase-3 inhibitor. In addition, a bitransgenic mouse model of severe cardiomyopathy, which overexpresses Gq protein and hematopoietic progenitor kinase-/germinal center kinase-like kinase, revealed the robust accumulation of the 130-kDa ROCK-1 cleaved fragment. This constitutively active ROCK-1 subspecies, when expressed in cardiomyocytes, led to caspase-3 activation, indicating a positive feed-forward regulatory loop. ROCK-1-dependent caspase-3 activation was coupled with the activation of PTEN and the subsequent inhibition of protein kinase B (Akt) activity, all of which was attenuated by siRNA directed against ROCK-1 expression. Similarly, ROCK-1-null mice (Rock-1(-/-)) showed a marked reduction in myocyte apoptosis associated with pressure overload. These data suggest an obligatory role for ROCK-1 cleavage in promoting apoptotic signals in myocardial hypertrophy and/or failure.
authors.affiliation: Center for Molecular Development and Disease, Institute of Biosciences and Technology, Texas A&M University System Health Science Center, 2121 West Holcombe Boulevard, Houston, TX 77030, USA.
authors.forename: Jiang
authors.initials: J
authors.lastname: Chang
authors.forename: Min
authors.initials: M
authors.lastname: Xie
authors.forename: Viraj R
authors.initials: VR
authors.lastname: Shah
authors.forename: Michael D
authors.initials: MD
authors.lastname: Schneider
authors.forename: Mark L
authors.initials: ML
authors.lastname: Entman
authors.forename: Lei
authors.initials: L
authors.lastname: Wei
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Schwartz
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism*; D002478:Cells, Cultured; D002518:Ceramides / Q000494:pharmacology; D003710:Demography; D004195:Disease Models, Animal; D004789:Enzyme Activation; D005260:Female; D006333:Heart Failure / Q000201:enzymology; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000737:chemistry / Q000172:deficiency / Q000378:metabolism*; D008297:Male; D051379:Mice; D008875:Middle Aged; D008957:Models, Genetic; D032383:Myocytes, Cardiac / Q000166:cytology* / Q000187:drug effects; D051059:PTEN Phosphohydrolase / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry / Q000172:deficiency / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D051381:Rats; D013599:Systole / Q000502:physiology; D054460:rho-Associated Kinases
chemical_list: D002518:Ceramides; D047908:Intracellular Signaling Peptides and Proteins; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D054460:rho-Associated Kinases; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human; C505407:CASP3 protein, human; C505409:Casp3 protein, mouse; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases