GTPase activity serves as the shutoff mechanism for the signaling roles of GTPases by returning the active, GTP-bound protein to the inactive, GDP-bound state.[1][2] Most “GTPases” have functional GTPase activity, allowing them to remain active (that is, bound to GTP) only for a short time before deactivating themselves by converting bound GTP to bound GDP.[2][3] However, many GTPases also use accessory proteins named GTPase-activating proteins or GAPs to accelerate their GTPase activity.