Role of Ras in signal transduction from the nerve growth factor receptor: relationship to protein kinase C, calcium and cyclic AMP.

A dominant inhibitory ras mutant (Ha-ras Asn-17) has been used to investigate the role of Ras in nerve growth factor (NGF)-mediated signal transduction in PC12 cells. Expression of Ha-Ras Asn-17 blocks neuronal differentiation of these cells in response to NGF treatment. The Ha-Ras Asn-17 block was bypassed by treatment with NGF plus dibutyryl cAMP or NGF plus the Ca 2+ ionophore ionomycin, but not by NGF plus 12-O-tetradecanoyl phorbol acetate (TPA)