Investigation of PKCδII and BAD protein complex formation (613.7)

Abstract

Protein kinase C δ (PKCδ) has been shown to have dual functions both as a regulator of apoptosis and cellular survival due to alternative splicing. One splice variant, PKCδII, is integral in promoting cell survivability. The pro‐apoptotic protein, BCL‐2 antagonist of cell death (BAD), will complex with and inhibit the function of pro‐survival proteins. Upon phosphorylation at Ser‐136, BAD disassociates from these complexes, conferring survival. It has been found that the overexpression of PKCδII coincides with increased BAD phosphorylation. Although the exact mechanism is unknown, we believe PKCδII enhances this phosphorylation via direct interactions with BAD. We aim to elucidate the amino acid residues of PKCδII that bind BAD. We propose the interactions that complex PKCδII with BAD using information gained from sequence analyses and computational simulations. The amphipathic groove (Lys‐49, Val‐176, Leu‐220) of 14‐3‐3 has previously been demonstrated to interact with BAD. Upon alignment of the 14‐3‐3 and PKCδII amino acid sequences, it was noted that the residues that comprise the amphipathic groove may be conserved and also facilitate binding of PKCδII with BAD. The PKCδII residues Gln‐376, Val‐547, and Val‐586 may enable the formation of this complex. A homology model of PKCδII and BAD has aided in visualizing this interaction. Subsequent site‐directed mutagenesis will further solidify our understanding of this protein complex. These proposed interactions provide evidence to suggest that BAD complexes directly with PKCδII in a conserved amphipathic groove, thereby leading to increased survivability.Grant Funding Source: The CREST Program is supported by NSF‐DUE #1022793 and #1323414.