FIG. 8.

Model showing the role of dPDZ-GEF in the MAPK pathway. Various extracellular signals instigate the MAPK-related signaling cascade. Three GEFs, i.e., Sos, dC3G, and the newly discovered dPDZ-GEF, are involved in this pathway. dPDZ-GEF is the first genetically revealed GEF that is specific for Rap1. The dPDZ-GEF/Rap1 component shares the effector signaling pathway with the Sos/Ras component, and there are likely other effectors yet to be found. In this complex network, dPDZ-GEF controls cell fate and survival as an upstream regulatory component.