Question

Resetting the switch requires tightly bound GDP to dissociate. This is a slow step which is greatly accelerated by specific signals such as what?

Answer 1

Resetting of a G-protein switch is accelerated by the binding of a signaling molecule to a G-protein-coupled receptor, which leads to GDP dissociation and the activation of the G-protein.

Step-by-step explanation:

The resetting of a G-protein switch, which involves the dissociation of GDP from the G-protein α subunit, is a key regulator of cell signaling. The process is slow on its own but is significantly accelerated when a specific signal is received. This acceleration occurs when a signaling molecule binds to a G-protein-coupled receptor (GPCR), which prompts the α subunit to release GDP and pick up GTP, thus activating the G-protein. The β and γ subunits then dissociate from the α subunit, leading to a cellular response. Ultimately, the hydrolysis of GTP back to GDP by the α subunit terminates the signal, and the subunits reassemble, ready for another cycle of activation and signaling.