GTPase-activating protein for Rho family proteins (PubMed:33835025). Essential component of the CLIC (clathrin-independent carrier)/GEEC (GPI-anchored protein-enriched early endocytic compartment) endocytic pathway (PubMed:28993397). During hematopoiesis, inhibits Egfr-ras-MAPK signaling by promoting Spi-induced Egfr internalization through CLIC/GEEC endocytosis, thereby preventing plasmatocyte overproliferation (PubMed:28993397). Essential for normal mushroom body (MB) development and consequently the formation of olfactory long-term memories (PubMed:33892766). During MD development, required to stop the MB beta-lobe from crossing the brain midline, possibly acting via its role in the CLIC/GEEC endocytic pathway to down-regulate the Egfr-ras-MAPK signaling at the tip of the beta-lobes (PubMed:33892766). Required during embryo cellularization for maintaining and regulating the rate of actomyosin ring constriction (PubMed:33835025). During cellularization, inhibits Rho-GTP levels at the furrow canal tip in a spatiotemporal manner, thus delaying the onset of actomyosin contraction and ensuring appropriate closure of the cells at the base of nuclei after membrane extension (PubMed:33835025). Interacts with Egfr (when ubiquitinated). During embryonic cellularization, detected at the furrow canal tips with enrichment at the edges (PubMed:33835025). Recruited to the furrow tips at early cellularization, expression levels are highest during mid-cellularization but then decrease at late cellularization when it becomes predominately cytosolic (PubMed:33835025). In embryos and larvae, displays a punctate localization in the cytoplasm of plasmatocytes (PubMed:28993397). In larvae, also displays a punctate localization in hemolymph crystal cells (PubMed:28993397). During Egfr internalization, localizes with Egfr and spi, to punctate or tubular structures connected to the cell surface (PubMed:28993397). In the adult brain, expressed in the antennal lobe, the subesophageal ganglion and the alpha/beta neurons of the mushroom body. In the larval primary lymph gland, expressed throughout the medullary and cortical zones (at protein level). Also detected in larval and embryo plasmatocytes (at protein level). The Rho-GAP domain is necessary for inhibiting contractile ring constriction during cellularization. RNAi-mediated knockdown in embryos is lethal at 24 hr, likely due to defective cellularization (PubMed:33835025). During cellularization, the F-actin network at the base of the furrow canal is unorganized, the furrow tips contain wavy edges and there is a loss of contact between adjacent furrow tips (PubMed:33835025). Actomyosin ring constriction is enhanced, and the nuclei have a bottleneck appearance likely due to premature constriction at the furrow canal tip during the mid cellularization stage (PubMed:33835025). Another study reports that flies are viable and fertile (PubMed:28993397). RNAi-mediated knockdown in the alpha/beta neurons of the adult mushroom body (MB), results in abnormal crossing of the MB beta lobe over the brain midline (PubMed:33892766).