Le. Mcleod et al., beta-adrenergic agonists increase phosphorylation of elongation factor 2 in cardiomyocytes without eliciting calcium-independent eEF2 kinase activity, FEBS LETTER, 489(2-3), 2001, pp. 225-228
The beta -adrenergic agonist isoproterenol increased the phosphorylation of
elongation factor eEF2 in ventricular cardiomyocytes from adult rats (ARVC
). Phosphorylation of eEF2 inhibits its activity, and protein synthesis was
inhibited in ARVC concomitantly with increased eEF2 phosphorylation. eEF2
kinase activity in ARVC extracts was completely dependent upon Ca2+/calmodu
lin. In contrast to other cell types, however, treatments designed to raise
intracellular cAMP failed to induce Ca2+/calmodulin-independent activity.
Instead, they increased maximal eEF2 kinase activity, Similar data were obt
ained when partially purified ARVC eEF2 kinase was treated with cAMP-depend
ent protein kinase in vitro. These data suggest that ARVC possess a distinc
t isoform of eEF2 kinase. (C) 2001 Federation of European Biochemical Socie
ties, Published by Elsevier Science B.V. All rights reserved.