Fig. 3

The GDP/GTP-cycle of RhoA and its regulators. RhoA cycles between a GDP-bound “inactive” and a GTP-bound “active” state. When the RhoA is anchored to the plasma membrane it is accessible for the binding of a GEF which promotes the exchange of GDP for GTP. The GTP-bound active RhoA then interacts directly with effectors, activating them and inducing downstream signaling pathways. GAPs in turn catalyze the hydrolysis of GTP to GDP (+ P_i), bringing RhoA back into its inactive form. GDIs dislocate the RhoA-GDP from the plasma membrane, keeping it in the inactive state. GDFs on the other hand induce the dissociation of the GDIs from RhoA, allowing it’s translocation to the membrane and the start of a new GDP/GTP-cycle