Zinc induces specific association of PKC with membrane cytoskeleton

Putative binding sites for zinc are present in the regulatory domain of protein kinase C but a distinct role for zinc has not yet been proposed. Here we show that micromolar concentrations of zinc chloride cause pure rat brain protein kinase C to localize in a detergent-insoluble, cytoskeletal fraction of red cell membranes and to bind to isolated cytoskeleton in the presence of phosphatidylserine. Attachment of protein kinase C to cytoskeleton was accompanied by enhanced expression of binding sites for 3H-phorbol ester, a regulatory ligand of protein kinase C. The active factor in the cytoskeleton was labile to protease suggesting that protein kinase C binds to a cytoskeletal protein.