Cell type-specific expression of protein kinase C isozymes in the rabbit cerebellum

Monoclonal antibodies raised against rabbit brain protein kinase C were classified into at least three types, MC-1a, MC-2a, and MC-3a, which selectively interact with hydroxyapatite column chromatographically resolved isozymes type I, II, and III of protein kinase C, respectively, determined on the basis of immunoblotting experiments. Immunoprecipitating analysis revealed that MC-1a, -2a, and -3a interacted with protein kinase C expressed in the brain and MC-2a and -3a, but MC-1a immunoprecipitated the protein kinase from rabbit spleen. Immunocytochemical localization of the protein kinase isozymes in the rabbit cerebellum and spleen was studied using these monoclonal antibodies. Staining with MC-1a was restricted to Purkinje cells of the rabbit cerebellum, and there was no reaction product in the Purkinje cells with either MC-2a or MC-3a. Cells in the granular layer of the cerebellum were labeled with MC-2a, and oligodendroglia in the white matter of the cerebellum was stained with MC-3a. The rabbit spleen contained no product reacting with MC-1a, but MC-2a and MC-3a reacted with lymphocytes in the mantle zone and the periarterial lymphatic sheath of the white pulp, respectively. These results suggest that expression of the protein kinase C isozyme in the rabbit cerebellum may depend on the cell type.