Tyrosine 311 is phosphorylated by c-Abl and promotes the apoptotic effect of PKCδ in glioma cells

In this study we characterized the phosphorylation of tyrosine 311 and its role in the apoptotic function of PKCδ in glioma cells. We found that c-Abl phosphorylated PKCδ on tyrosine 311 in response to H2O2 and that this phosphorylation contributed to the apoptotic effect of H2O2. In contrast, Src, Lyn, and Yes were not involved in the phosphorylation of tyrosine 311 by H2O2. A phosphomimetic PKCδ mutant, in which tyrosine 311 was mutated to glutamic acid (PKCδY311E), induced a large degree of cell apoptosis. Overexpression of the PKCδY311E mutant induced the phosphorylation of p38 and inhibition of p38 abolished the apoptotic effect of the PKCδ mutant. These results suggest an important role of tyrosine 311 in the apoptotic function of PKCδ and implicate c-Abl as the kinase that phosphorylates this tyrosine.