Evaluate the significance of the seven transmembrane domains in GPCRs.

• A. They allow GPCRs to interact with both extracellular ligands and intracellular signaling proteins.
• B. They are responsible for the degradation of GPCRs.
• C. They are only involved in the structural stability of the cell membrane.
• D. They prevent GPCRs from interacting with any ligands.

Answer: (A)