Differential roles of MAPKs and MSK1 signalling pathways in the regulation of c-Jun during phenylephrine-induced cardiac myocyte hypertrophy.

Gq-protein-coupled receptor (GqPCR) signalling is associated with the induction of cardiac myocyte hypertrophy, which is characterized by an increase in expression of immediate early genes via activation of pre-existing transcription factors. Here, we explore the role of MSK1 and MAPK signalling pathways in the regulation of the immediate early gene c-jun. The results provide further support for the role of MSK1 in cardiac myocyte hypertrophy and indicate that PE activates distinct signalling mechanisms which culminate with a complex activation of c-jun.

Regulation of BAD protein by PKA, PKCdelta and phosphatases in adult rat cardiac myocytes subjected to oxidative stress.

H2O2, as an example of oxidative stress, induces cardiac myocyte apoptosis. Bcl-2 family proteins are key regulators of the apoptotic response while their functions can be regulated by post-translational modifications including phosphorylation, dimerization or proteolytic cleavage. In this study, we examined the role of various protein kinases in regulating total BAD protein levels in adult rat cardiac myocytes undergoing apoptosis.

Myogenin-dependent nAChR clustering in aneural myotubes.

During development of the neuromuscular junction, nerve-derived agrin and the cell substrate laminin stimulate postsynaptic nAChR clustering. This clustering is dependent on activation of the tyrosine kinase, MuSK, which signals receptor clustering via a rapsyn-dependent mechanism. Myogenin is a muscle-specific transcription factor that controls myoblast differentiation and nAChR gene expression.

CaM kinase II-dependent phosphorylation of myogenin contributes to activity-dependent suppression of nAChR gene expression in developing rat myotubes.

During development of the neuromuscular junction (NMJ), extrajunctional expression of genes, whose products are destined for the synapse, is suppressed by muscle activity. One of the best-studied examples of activity-dependent gene regulation in muscle are those encoding nicotinic acetylcholine receptor (nAChR) subunits. We recently showed that nAChR gene expression is inhibited by calcium/calmodulin-dependent protein kinase II (CaMKII) and CaMKII inhibitors block activity-dependent suppression of these genes.