KCS

Protein Kinase C (PKC) is a multi-gene subfamily of serine-threonine kinases comprising of at least ten isoforms which play important roles in multitudes of cellular processes as proliferation, differentiation, growth, and apoptosis. PKCδ is one of the important isoforms among the PKCs in regulating various cellular processes including cell survival and apoptosis. Activation of PKCδ is correlated with apoptosis in various cell types. Phosphorylation of Thr505, Ser643 and Ser662 are crucial in activation of PKCδ. Furthermore, phosphorylation of tyrosine residues, in particular that of Tyr311, is related with PKCδ activation and induction of apoptosis. Here, we mutated Ser662 to Ala and generated phosphorylation-deficient mutant of PKCδ (PKCδ-S662A) and studied the effect of this mutation in inducing apoptosis in L929 murine fibroblsasts. We report that this mutation renders PKCδ apoptotically more active. Furthermore, the mutant PKCδ-S662A is more tyrosine phosphorylated and translocated to the membrane faster than its wild type counterpart.