The p120-RasGAP C-terminus contains a GAP domain that catalyses the activation of H-Ras by hydrolyzing GTP-bound active Ras into an inactive GDP-bound form of Ras. Inactivation of H-Ras by EPHB2 down regulates MAP kinase phosphorylation and induces neurite retraction in neuronal cells (Elowe et al. 2001, Tong et al. 2003).
GTPase activator activity of p-EPHBs:EFNBs:RASA1:HRAS:GTP [plasma membrane]