New insights into PKC family affairs: three novel phosphorylation sites in PKCepsilon and at least one is regulated by PKCalpha

Abstract

PKCepsilon (protein kinase Cepsilon) is a serine/threonine kinase, and a member of the PKC family of isoforms. The different PKC isoforms regulate many cellular processes of importance for disease. It is therefore desirable to obtain tools to specifically modulate the activity of the individual isoforms and to develop markers of PKC activity. The paper by Durgan et al. in this issue of the Biochemical Journal has taken us some steps further towards these goals. In the paper they identify three previously unknown phosphorylation sites in PKCepsilon. All of them are specific for the epsilon isoform, evolutionarily conserved and tightly regulated. The phosphorylation of one site is critical for the binding of PKCepsilon to 14-3-3beta, suggesting it is of functional importance. The results provide important novel findings that uncover new aspects of PKCepsilon regulation and reveal new possibilities for detecting PKCepsilon activity in situ.