May be a transforming oncogene with exchange activity for CDC42 (By similarity). May be a guanine-nucleotide exchange factor (GEF) for RAC1 and CDC42. Activated by the binding to subunits beta and gamma of the heterotrimeric guanine nucleotide-binding protein (G protein) (PubMed:18045877). Involved in the regulation of actin polymerization (PubMed:26573021). {ECO:0000250|UniProtKB:Q6KAU7, ECO:0000269|PubMed:18045877, ECO:0000269|PubMed:26573021}. This is the function of ENSG00000090924 (PLEKHG2, pleckstrin homology and RhoGEF domain containing G2).