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

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.

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► Activated PKCδ stimulates cytoplasmic translocation of C/EBPα protein.
► Activated PKCδ enhances phosphorylation of C/EBPα.
► Two new phosphosites of C/EBPα have been identified.