GTPase-activating protein (GAP) for Rho1; functions with the ERM protein Moe to regulate Rho1 and control proliferation in the developing epithelium. Recruited by Moe to the cell cortex where it negatively regulates Rho1 activity. Can also promote cell proliferation independently of its GAP activity, perhaps by acting with Arf51F (Arf6) to positively regulate Rac1. Interacts with Moe (via FERM domain). Recruited by Moe to the cell cortex. In the epithelium, predominately expressed at the apical cortex. RNAi-mediated knockdown does not affect epithelial integrity or apoptosis.