Functions as guanine nucleotide exchange factor that activates RAC1. May have relatively low activity (PubMed:23375260 and PubMed:20702777). Plays a role in the response to class 3 semaphorins and remodeling of the actin cytoskeleton. Plays a role in TNFSF11-mediated osteoclast differentiation, especially in podosome rearrangement and reorganization of the actin cytoskeleton. Regulates the activation of ITGB3, integrin signaling and cell adhesion. Interacts with PLXNA1. Interaction with PLXNA1 or PIP5K1C lowers its guanine nucleotide exchange activity. Dissociates from PLXNA1 when SEMA3A binds to the receptor. Interacts with PIP5K1C via its FERM domain. The interaction with PIP5K1C is enhanced by SEMA3A binding. Interacts with RAC1. Detected in adult brain, lung and testis. Detected in embryonic hippocampus and brain cortex. Up-regulated by TNFSF11. Intramolecular interaction between the DH domain and the PH domains can stabilize the protein in an autoinhibited conformation.