May be a transforming oncogene with exchange activity for CDC42. May be a guanine-nucleotide exchange factor (GEF) for RAC1 and CDC42 (PubMed:11839748). Activated by the binding to subunits beta and gamma of the heterotrimeric guanine nucleotide-binding protein (G protein) (By similarity). Involved in the regulation of actin polymerization (By similarity). Expressed in thymus, skeletal muscle, lung, testis, uterus, pancreas and heart and also expressed during embryogenesis.