Conformational analysis in solution of protein kinase C betaII V5-1 peptide.

One of protein kinase C (PKC) isozymes, PKC beta binds to receptor for activated C kinase 1 (RACK1), and their complex is suggested to be translocated to melanosomes. The binding site of PKC beta for RACK1 is considered one of its catalytic domains, V5 domain which consists of three motifs such as V5-1, V5-2, and V5-3. Among these, V5-1 region, extreme C-terminal residues of PKC beta showed the highest RACK1-binding affinity. PKC beta can be classified into PKC betaI and PKC betaII based on their different V5 domains. RACK1-binding affinity of PKC betaII is five times greater than that of PKC betaI. The structures of PKC betaI, PKC betaII, and RACK1 are not known. However, the conformational study on PKC betaII V5-1 region showing high RACK1-binding selectivity may help us in understanding the interaction between RACK1 and PKC betaII.