The step immediately following the binding of aligand to a G -protein coupled receptor is
A) Dissociation of the a subunit from the $\beta$ and Ƴ subunit
B) Activation of some protein by the a subunit
C) Exchange of GTP for GDP on the a subunit
D) Hydrolysis of GTP by the a subunit
E) Exchange of GTP for GDP on the $\beta$Ƴ subunit

Question

Quizplus · Accepted Answer

The immediate step after a ligand binds to a G-protein coupled receptor (GPCR) is the exchange of GTP for GDP on the alpha (α) subunit. This exchange activates the G-protein by allowing the α subunit to dissociate from the β and γ subunits, enabling it to interact with downstream effectors.

The Step Immediately Following the Binding of Aligand to a G