In order to investigate the effects of protein kinase C (PKC) expression on cellular growth and morphology, we established mouse fibroblast cell populations which expressed the rat pkc-γ gene under the control of a retroviral promoter. NIH 3T3 stable transfectants displayed a three-fold increase in total PKC levels. These cells appeared morphologically unaltered but exhibited a stronger mitogenic response to 12-O-tetradecanoylphorbol-13-acetate (TPA) and cardiolipin (CL) as well as enhanced growth in semisolid medium in the presence of TPA. Thus, at these enzyme levels, PKC conferred growth advantages to NIH 3T3 cells only in response to specific activators.
