REGULATION OF PROTEIN-KINASE-C IN NG108-15 CELL-DIFFERENTIATION

The involvement of PKC in NG108-15 cell differentiation was investigat ed. Differentiation with dBcAMP was associated with a decrease in tota l cellular phorbol ester binding. The histone-directed PKC activity wa s decreased in the soluble fraction. Northern and Western blotting rev ealed the presence of only PKC alpha but not PKC beta and PKC gamma am ong the calcium-dependent isoforms. Differentiation induced a decrease of cytosolic PKC alpha immunoreactivity, with no changes of mRNA cont ent or appearance of PKC beta and PKC gamma isoforms. The low levels o f PKC alpha in the soluble fraction suggest that the mRNA for this spe cies is less efficiently translated in differentiated NG108-15 cells. The data suggest that downregulation of PKC alpha protein and kinase a ctivity are associated with induction of neuronal morphology in NG108- 15 cells. (C) 1994 Academic Press, Inc.