CELLULAR MECHANISMS OF CARDIAC-HYPERTROPHY

Hypertrophy of myocytes in the heart ventricles is an important adapta tion that in vivo occurs in response to a requirement for increased co ntractile power. It involves changes at the level of gene transcriptio n, stimulation of the rate of protein synthesis (translation), and inc reased assembly of myofibrils. There is mounting evidence of the invol vement of reversible protein phosphorylation and dephosphorylation in most of these processes. Protein kinase C, mitogen-activated protein k inases, and transcription factors have been implicated in the modulati on of the transcriptional changes. Activation of translation may also be mediated through protein phosphorylation/dephosphorylation, althoug h this has not been clearly established in the heart. Here we provide a critical overview of the signalling pathways involved in the hypertr ophic response and provide a scheme to account for many of its feature s.