Question

After a Gprotein is activated by a receptor, what is the next thing that happens to the Gprotein?

1) The Gprotein phosphorylates the a subunit
2) The Gprotein breaks into ab and y subunits
3) The Gprotein hydrolyzes GTP to GDP
4) The Gprotein creates cAMP
5) None of the above

Answer 1

After activation by a receptor, a G-protein splits into alpha and beta-gamma subunits, leading to the activation of other intracellular enzymes or molecules and downstream cellular responses.

Step-by-step explanation:

After a G-protein is activated by a receptor, the next step is that the G-protein breaks into the α (alpha) and βγ (beta and gamma) subunits, which is option 2. This process leads to downstream effects that result in cellular responses. An activated G-protein undergoes a conformational change that causes GDP to be released and replaced with GTP. The exchange of GDP for GTP causes the α subunit to dissociate from the βγ subunits.

The α subunit or the βγ complex then goes on to activate other molecules or enzymes within the cell, such as adenylyl cyclase, which then catalyzes the conversion of ATP to cAMP. This sequence of events is crucial for transmitting signals from outside the cell to the inside, leading to various cellular responses.