This entry includes RalGPS1 (also known as RalGEF2) and RalGPS2. RalGPS1 and RalGPS2 are guanine nucleotide exchange factors for Ral (RalA and RalB), a ubiquitously expressed Ras-like small GTPase [, ]. The PH-PxxP domain of RalGPS2 acts as a negative regulator for RalA GTPase activation and promotes PC12 cellsdifferentiation [].