GTPase-activating protein (GAP) promoting GTP hydrolysis on RHOA, CDC42 and RAC1 small GTPases. May be involved in the differentiation of neuronal cells during the formation of neurite extensions. Involved in NMDA receptor activity-dependent actin reorganization in dendritic spines. May mediate cross-talks between Ras- and Rho-regulated signaling pathways in cell growth regulation. Isoform 2 has higher GAP activity (By similarity). {ECO:0000250, ECO:0000269|PubMed:12446789, ECO:0000269|PubMed:12454018, ECO:0000269|PubMed:12531901, ECO:0000269|PubMed:12788081, ECO:0000269|PubMed:12819203, ECO:0000269|PubMed:12857875, ECO:0000269|PubMed:17663722}. This is the function of ARHGAP32 (Rho GTPase activating protein 32, ENSG00000134909).