title: Calcineurin and beyond: cardiac hypertrophic signaling.
abstract: In response to increased ventricular wall tension or neurohumoral stimuli, the myocardium undergoes an adaptive hypertrophy response that temporarily augments pump function. Although initially beneficial, sustained cardiac hypertrophy can lead to decompensation and cardiomyopathy. Recent studies have focused on characterizing the molecular mechanisms that underlie cardiac hypertrophy. An increasing number of signal transduction pathways have been identified as important regulators of the hypertrophic response, including the low-molecular weight GTPases (Ras, RhoA, and Rac), mitogen-activated protein kinases, protein kinase C, and calcineurin. This review will discuss an emerging body of evidence that implicates the calcium-calmodulin-activated protein phosphatase calcineurin as a physiological regulator of the cardiac hypertrophic response. Although the sufficiency of calcineurin to promote cardiomyocyte hypertrophy in vivo and in vitro is established, its overall necessity as a hypertrophic mediator is currently an area of ongoing debate. The use of the calcineurin-inhibitory agents cyclosporine A and FK506 have suggested a necessary role for calcineurin in many, but not all, animal models of hypertrophy or cardiomyopathy. The evidence implicating a role for calcineurin signaling in the heart will be weighed against a growing body of literature suggesting necessary roles for a diverse array of intracellular signaling pathways, highlighting the multifactorial nature of the hypertrophic program.
authors.affiliation: Department of Pediatrics, University of Cincinnati, Division of Molecular Cardiovascular Biology, Children's Hospital Medical Center, Cincinnati, Ohio, USA. molkj0@chmcc.org
authors.forename: J D
authors.initials: JD
authors.lastname: Molkentin
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D019703:Calcineurin / Q000235:genetics / Q000378:metabolism*; D065095:Calcineurin Inhibitors; D006332:Cardiomegaly / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D002467:Cell Nucleus / Q000378:metabolism; D016572:Cyclosporine / Q000494:pharmacology / Q000627:therapeutic use; D003593:Cytoplasm / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology / Q000627:therapeutic use; D007166:Immunosuppressive Agents / Q000494:pharmacology / Q000627:therapeutic use; D051379:Mice; D008822:Mice, Transgenic; D023421:Models, Animal; D008969:Molecular Sequence Data; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000378:metabolism; D016559:Tacrolimus / Q000494:pharmacology / Q000627:therapeutic use; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D065095:Calcineurin Inhibitors; D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D007166:Immunosuppressive Agents; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D014157:Transcription Factors; D016572:Cyclosporine; D019703:Calcineurin; D016559:Tacrolimus