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. Interacts with GNA12 and GNA13, probably through the RGS-like domain. Interacts with RHOA, PLXNB1 and PLXNB2. Interacts through its PDZ domain with IGF1R beta subunit. Interacts with GCSAM. Translocated to the membrane upon stimulation. Ubiquitously expressed. Isoform 2 is found in jejunum and testis. A chromosomal aberration involving ARHGEF12 may be a cause of acute leukemia. Translocation t(11;11)(q23;23) with KMT2A/MLL1. Contaminating sequence. Potential poly-A sequence.