A novel Ras-like GTPase, Rit1 induces c-fos serum responsive element via a p62TCF/EIk-1-independent parhway

A novel branch of the Ras GTPase subfamily, Ri시, has been known to regulate cell proliferation. In the present study, we investigated Rit1 signaling pathway leading to activation of c-fos serum response element (SRE). Using a c-fos SRE reporter gene, we showed that a constitutively active form of Rit1, Rit1Q79L, stimulates c-fos SRE reporter activity in a dose-dependent manner. Interestingly, the c-랜 SRE activation by RasV12 was markedly inhibited by pre-treatment with u0126, a specific inhibitor of MEK1/2, whereas Rit1Q79L-induced SRE activation was not affected. Consistently, RasV12 induced transcactivation of GAL4-Elk-1, but Rit1Q79L failed to do it. Taken together, these results suggest that Rit1 induces c-랜 SRE activation via an Elk-1-independent pathway.