Functions as a RHOA-specific guanine nucleotide exchange factor regulating signaling pathways downstream of integrins and growth factor receptors. Functions in axonal branching, synapse formation and dendritic morphogenesis. Functions also in focal adhesion formation, cell motility and B-lymphocytes activation. May regulate NEFL expression and aggregation and play a role in apoptosis. Homooligomer; forms cytoplasmic aggregates. Forms a complex with MAPK8 and MAPK8IP1. Interacts with RHOA. Interacts with microtubules. Interacts with YWHAE and YWHAH. Interacts with PTK2/FAK1. Interacts with NEFL. Interacts with CTNND2; prevents interaction with RHOA (By similarity). Colocalizes with the microtubule radial and cortical systems. Phosphorylated on tyrosine upon stimulation of cells by laminin.