Localization of non-conventional protein kinase C isoforms in bovine brain cell nuclei

Abstract

Using Western blotting and immunofluorescence microscopy we detected the protein kinase C isoforms δ, Σ and ζ in isolated cell nuclei from bovine cerebral cortex. Both protein kinase C (PKC) δ and PKC Σ are present in higher concentrations in neuronal than in glial nuclei and are located inside the nucleus and at the nuclear envelope. There they give a punctate staining in immunofluorescence microscopy. PKC ζ is also present both in the nucleoplasm and at the nuclear envelope. PKC η could not be detected in the cell nuclei and, even in the homogenate of cerebral cortex, this isoform is present only in very low concentrations. The antibody against PKC η bound strongly to a nucleoplasmic protein with an apparent molecular mass of 99 kDa. The localization of non-conventional PKC isoforms at the cell nucleus strongly indicates that these isoforms are directly involved in the regulation of nuclear processes.