PKCδ enhances C/EBPα degradation via inducing its phosphorylation and cytoplasmic translocation

Abstract

Our previous study has shown that PKCδ stimulates proteasome-dependent degradation of C/EBPα, which partially contributes to PKCδ-mediated apoptosis. However, the molecular interrelationship between these two important proteins is still unknown. In this study, we reported that C/EBPα was phosphorylated by activated PKCδ on three serines, two of which were reported for the first time. Phosphorylated C/EBPα underwent cytoplasmic translocation, which led to the inactivation of its transcriptional activity. Inactive cytoplasmic C/EBPα was finally subjected to proteasome degradation. This work reveals the exquisite molecular events linking activated PKCδ and C/EBPα degradation during cell apoptosis.