Question

Which of the following is different between stimulatory and inhibitory G proteins in the cyclic AMP pathway? a)β subunit b)α subunit c)only the inhibitory G protein acts as a guanine nucleotide exchange factor (GEF) d)only the stimulatory G protein binds GTP

Answer 1

In the cyclic AMP pathway, the main difference between stimulatory and inhibitory G proteins is that only the stimulatory G protein binds GTP. The stimulatory G protein triggers the production of cyclic AMP (cAMP) which then activates other proteins that affect gene transcription. The inhibitory G protein acts by inhibiting the production of cAMP.

Step-by-step explanation:

In the cyclic AMP pathway, the main difference between stimulatory and inhibitory G proteins is that only the stimulatory G protein binds GTP. When a signaling molecule binds to a G-protein-coupled receptor, the G protein alpha (α) subunit exchanges GDP for GTP. This activation of the stimulatory G protein triggers the production of cyclic AMP (cAMP) which then activates other proteins that affect gene transcription. On the other hand, the inhibitory G protein does not bind GTP and does not have a role in generating cAMP. Instead, it acts by inhibiting the production of cAMP by adenylate cyclase, thereby exerting an inhibitory effect on the pathway.