9. Which of the statement is INCORRECT for GTPase?
(A) GTP-bound as the "on" state
(B) GDP-bound as the "off" state
(C) GTPase activating proteins switch GTPases from "off" to "on" state
(D) guanine nucleotide-exchange factor release GDP from GTPases
(E) Two major classes of GTPases: trimeric and monomeric G proteins