As inferred from mouse, RGC1:RGC2 (RALGAPB:RALGAPA2) activate the GTPase activity of RALA (Chen et al. 2011).
RALA is a guanine nucleotide binding protein that hydrolyzes bound GTP to yield GDP and phosphate. RGC1 and RGC2 are GAPs (GTPase-activating proteins) that activate the GTPase activity of RALA. Insulin activates AKT, which phosphorylates RGC2, inactivating the GAP activity of RGC1:RGC2 and allowing RALA:GTP to accumulate.