PLEKHG6 functions as a guanine nucleotide exchange factor activating the small GTPase RHOA, which, in turn, induces myosin filament formation. It activates RHOG but not activate RAC1, or to a much lower extent than RHOA and RHOG. Part of a functional unit, involving MyoGEF, MYH10 and RHOA, at the cleavage furrow to advance furrow ingression during cytokinesis. In epithelial cells, required for the formation of microvilli and membrane ruffles on the apical pole. Along with EZR, required for normal macropinocytosis.