Prostate cancer (PC) patients die from progression to androgen independence (AI) and chemoresistance (CR). Protein kinase Cmu (PKCmu) a novel member of the PKC family of signal transduction proteins is downregulated in Al PC. Studying PKCmu interactors in the yeast two-hybrid system identified metallothionein 2A (NIT 2A) as an interactor of PKCmu kinase domain (KD) in PC, which was quantified by beta-gal assay, confirmed in PC cells by immunoprecipitation, and PKCmu-MT 2A co-localization in vivo by immunofluorescence studies. PKCmu domain interaction studies revealed that MT 2A interacted strongly with KID, relatively weakly with C I, and failed to interact with C2, PH or kinase mutant domains. Peptide library and in silico analysis strongly suggest that NIT 2A is a novel substrate of PKCmu and our data indicate that the PKCmu-MT 2A interaction depends on PKCmu kinase activity. Because metallothioneins are associated with cell proliferation and CR, the PKCmu-MT 2A interaction may contribute to CR and/or Al in PC. (C) 2003 Elsevier Inc. All rights reserved.