The activation of neuronal NO synthase is mediated by G-protein beta gammasubunit and the tyrosine phosphatase SHP-2

In CHO cells we had found that CCK positively regulated cell proliferation via the activation of a soluble guanylate cyclase, Here we demonstrate that CCK stimulated a nitric oxide synthase (NOS) activity. The production of N O was involved in the proliferative response elicited by CCK regarding the inhibitory effect of NOS inhibitors L-NAME and alpha-guanidinoglutaric acid . We identified the NOS activated by the peptide as the neuronal isoform: t he expression of the C415A neuronal NOS mutant inhibited both CCK-induced s timulation of NOS activity and cell proliferation, These two effects were a lso inhibited after expression of the C459S tyrosine phosphatase SHP-2 muta nt and the beta ARK1 (495-689) sequestrant peptide, indicating the requirem ent of activated SHP-2 and G-beta gamma subunit, Kinetic analysis (Western blot after coimmunoprecipitation and specific SHP-2 activity) revealed that in response to CCK-treatment, SHP-2 associated to G-beta 1 subunit, became activated, and then dephosphorylated the neuronal NOS through a direct ass ociation, These data demonstrate that the neuronal NOS is implicated in pro liferative effect evoked by CCK, A novel growth signaling pathway is descri bed, involving the activation of neuronal NOS by dephosphorylation of tyros yl residues.-Cordelier P., Esteve, J.-P., Rivard, N., Marletta, M., Vaysse, N., Susini, C., Buscail, L. The activation of neuronal no synthase is medi ated by G-protein beta gamma subunit and the tyrosine phosphatase SHP-2.