GEFH1 binds ASAP1 and regulates podosome formation

► Invadopodia and podosomes are regulated by Arf and Rho family GTP-binding proteins. ► Arf regulators, including ASAP1, have been identified in podosome function but Rho regulators have not. ► GEF-H1, a Rho family exchange factor, was identified as a binding partner of ASAP1. ► GEF-H1opposes the effects of ASAP1 on the formation of podosomes. ► A complex of ASAP1 with GEF-H1 regulates podosome dynamics.