Part of signaling pathway that is required for completion of cytokinesis. gapA and rgaA control cortexillin localization to the cleavage furrow and hence may be involved in cleavage of the midbody in the final stage of cytokinesis by regulating the actin cytoskeleton. Forms a complex by linking activated rac1A to ctxA in the absence of rgaA. Assembly of this complex is necessary for the recruitment of cortexillin to the midzone of the dividing cell. Heterotetramer. Quaternary complex with activated rac1A, ctxA and ctxB in the absence of rgaA. Not required for development. Rapidly up-regulated by hyperosmotic stress, which is dependent on dstC. Strongly inducible by 8-bromo-cGMP and to a lesser extent by 8-bromo-cAMP. Not induced by DIF (differentiation-inducing factor- a chlorinated hexaphenone). Cells initiate cleavage furrow formation but rarely complete cytokinesis. They grow as giant and multinucleate cells both on a substratum and in suspension culture with increased cell mass but development remains unaffected. Mutants lacking both rgaA and gapA are extremely large, flat and multinucleate, and exhibit cytokinesis defects similar to that seen with simultaneous loss of ctxA and ctxB. Starved null cells form normal fruiting bodies with viable spores at the same time as wild-type cells and the increase in size of the plaque on the bacterial lawn and the terminal phenotype also unaffected. Earlier stages of cytokinesis characterized by accumulation of myosin II at the furrow not affected.