試題詳解

26. Which of the following statements regarding heterotrimeric G protein and G-protein-mediated signaling is correct?

(1) The alpha subunit of heterotrimeric G protein (G-alpha), belong to the larger group of enzymes called GTPase.

(2) There are several different classes of heterotrimeric G-proteins that are defined by their different G-alpha, G-beta or G-gamma subunits.

(3) G-protein coupled receptors (GPCRs) associate with heterotrimeric G-proteins. Upon ligand binding to GPCRs, G-alpha hydrolyze bounded GTP to GDP and dissociate from the other subunits of heterotrimeric G-proteins.
(A) (1) and (2)
(B) (1) and (3)
(C) (2) and (3)
(D) All are correct
(E) None is correct