Rkp1/CPC2, a RACK1 homolog, interacts with Pck1 to regulate PKC-mediated signaling in Schizosaccharomyces pombe

Abstract

The Rkp1/CPC2, a receptor for activated protein kinase C of Schizosaccharomyces pombe, contains seven WD motifs found in the G-protein β-subunit. A 110-kDa protein was identified to interact with Rkp1/CPC2 by immunoprecipitation and following in vitro binding assay. To examine its kinase activity and binding ability to Rkp1, the pck1+, a PKC homolog of S. pombe, was cloned. Pck1 phosphorylated myelin basic protein (MBP) and histone H1 in a phospholipid-dependent and Ca2+-independent manner. It was demonstrated that the N-terminal region of Pck1 was responsible for the binding to Rkp1, thus suggesting that Rkp1 interacted with Pck1 to regulate Pck1-mediated signaling in S. pombe.