Seems to play a role in the regulation of RhoA GTPase by guanine nucleotide-binding alpha-12 (GNA12) and alpha-13 (GNA13) subunits. Acts as GTPase-activating protein (GAP) for GNA12 and GNA13, and as guanine nucleotide exchange factor (GEF) for RhoA GTPase. Activated G alpha 13/GNA13 stimulates the RhoGEF activity through interaction with the RGS-like domain. This GEF activity is inhibited by binding to activated GNA12. Mediates angiotensin-2-induced RhoA activation. Isoform 3 and isoform 4 do not homooligomerize and show an enhanced RhoGEF activity. Interacts with RHOA, GNA12 and GNA13 (By similarity). Homooligomerizes through the coiled coil region. Interacts with CTNNAL1 (By similarity). May interact with CCPG1. Translocated to the membrane by activated GNA13 or LPA stimulation. Ubiquitously expressed. The RGSL domain, also known as rgRGS domain, is necessary but not sufficient for full GAP activity. The DH domain is involved in interaction with CCPG1. Phosphorylated by PKCA (By similarity). Angiotensin-2 induced Tyr-737 phosphorylation is mediated by JAK2. Isoform 5 is phosphorylated at 'Ser-390'. Mice have reduced response to angiotensin-2 and lowered RhoA signaling pathway. Ref.2 sequence was originally submitted as from rat origin.