IGF1 Activates PKC α-Dependent Protein Synthesis in Adult Rat Cardiomyocytes

Acute exposure to interleukin 1 beta (IL1β) or insulin-like growth factor 1 (IGF1) promoted the translocation of PKC α from the cytosol to the membrane of adult rat cardiomyocytes. Western analysis demonstrated that membranal localization of PKC α was increased from 23% in the control to 49% after exposure to IGF1, and it was increased to 42% after exposure to IL1β. Activation of Erk1/Erk2 by IGF1 and IL1β was studied using a phosphorylation-specific antibody. IGF1-induced activation of p44/p42 MAP kinase was blocked by preincubation with the PKC inhibitors, bisindolylmaleimide and Gö6976, as well as the tyrosine kinase inhibitor, genistein. IGF1 increased the rate of protein synthesis, indicated by the increase in l-[¹⁴C(U)] phenylalanine incorporation over time, and this effect was inhibited by Gö6976.