How does binding of a ligand (such as epinephrine) activate a G protein coupled receptor? The ligand binds to the alpha subunit

Question

How does binding of a ligand (such as epinephrine) activate a G protein coupled receptor?
The ligand binds to the alpha subunit of the G protein and induces release of GDP.
The ligand phosphorylates the G-protein coupled receptor.
Ligand binding causes dimerization of G protein coupled receptors.
Ligand binding induces a conformation change in the cytosolic domain of the receptor.

Kunduz · Accepted Answer

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