CHARACTERIZATION AND DIFFERENTIAL EXPRESSION OF PROTEIN-KINASE-C ISOFORMS IN PC12 CELLS - DIFFERENTIATION PARALLELS AN INCREASE IN PKC BETA(II)

Nerve growth factor (NGF) treatment of PC12 cells induced a 2.8-fold increase in protein kinase C activity concomitant with differentiation and acquisition of neurites. PKC protein isoforms were separated by sequential chromatography on DEAE-Sephacel/hydroxylapatite. A broad peak of PKC activity eluted which corresponded to the alpha PKC isoform. In control cells, message for all six PKC isoforms was detected and expressed as epsilon > zeta = gamma > delta > beta > alpha. Western blot of whole cell lysates revealed a large increase in the beta(II), while slight changes were observed for the other five PKC isoforms during treatment (1-14 days) with HGF (50 ng/ml). In parallel, coordinate changes in the expression of the individual transcripts for the six isoforms occurred during NGF treatment. Induction and accumulation of PKC beta(II) may play a role in maintenance of neuronal morphology.