The primary function of the GAP domain is to accelerate the intrinsic GTPase activity of G-proteins. By increasing the rate at which GTP is hydrolyzed to GDP, GAPs effectively turn off the GTPase signaling. This is vital for ensuring that signaling pathways are tightly regulated and do not remain active longer than necessary. GAPs bind to the active, GTP-bound form of GTPases and stabilize the transition state for GTP hydrolysis, thereby promoting the conversion to the inactive GDP-bound state.
