May play a role in the regulation of RhoA GTPase by guanine nucleotide-binding alpha-12 (GNA12) and alpha-13 (GNA13). Acts as guanine nucleotide exchange factor (GEF) for RhoA GTPase and may act as GTPase-activating protein (GAP) for GNA12 and GNA13 (By similarity). Interacts with GNA12 and GNA13, probably through the RGS-like domain, with RHOA, PLXNB1 and PLXNB2, and through its PDZ domain with IGF1R beta subunit. Interacts with GCSAM. Translocated to the membrane upon stimulation. Expressed in brain, predominantly in neuronal cell bodies. Extended N-terminus.