[Rho-associated protein kinase is involved in establishing the contractile phenotype of cardiomyocytes].

It has been shown that Y-27632, an inhibitor of Rho-associated kinase, delays sarcomere assembly in rat neonatal cardiomyocytes pretreated with angiotensin II. Y-27632 affects the beat rate of cardiomyocytes; however, this effect is only observed at high cell density and, therefore, seems to be related to the formation of gap junctions between adjacent cardiomyocytes. Consistent with this suggestion, we established that Rho-associated kinase is localized in myofibrillar Z-discs of human myocardium and intercalated discs, the structures enriched in gap junctions. We propose that Rho-associated kinase participates in the maturation of the myocardial contractile system through phosphorylation of its molecular targets in Z-discs and intercalated discs.