RET phospho-Tyr981 binds the cytoplasmic tyrosine kinase SRC (Encinas et al. 2004). Recently, a yeast-two-hybrid screen led to the identification of the GTPase-activating protein (GAP) for Rap1, RAP1GAP, as a novel RET-binding protein (Jiao et al. 2011). Like SRC, Rap1GAP was also found to require phosphorylation of Tyrosine-981 for RET binding and suppressed GDNF-induced activation of ERK and neurite outgrowth.