The protein kinase C inhibitor, Ro-31-7459, is a potent activator of ERK and JNK MAP kinases in HUVECs and yet inhibits cyclic AMP-stimulated SOCS-3 gene induction through inactivation of the transcription factor c-Jun

► Ro-317549 triggers hyper-phosphorylation of c-Jun in HUVECs. ► Elevations in intracellular cyclic AMP also induce JNK-dependent, c-Jun activation. ► c-Jun is required for the full transcriptional activation of the human SOCS-3 gene. ► Ro-317549, GF-109203X and Gö 6983 inhibit c-Jun and SOCS-3 gene induction.