Promotes the exchange of Ras-bound GDP by GTP. Homooligomer and heterooligomer with RASGRF2. Interacts with USP8, thereby regulating its stability (By similarity). The DH (DBL-homology) domain mediates interaction with RASGRF2. Phosphorylated by PLK2, leading to ubiquitination and degradation by the proteasome. Ubiquitinated and degraded following phosphorylation by PLK2. Phosphorylated by SRC and LCK. Phosphorylation by LCK increases its capacity to stimulate the GDP/GTP exchange on Ras, whereas its phosphorylation by SRC seems not to have an effect on stimulation activity (By similarity).