A researcher is studying a G protein-coupled receptor in eukaryotic cells. In one group of cells, he notices that even though a ligand can bind to its G protein-coupled receptor, nothing happens. Why could this happen?
A)The G protein-coupled receptor might carry a mutation, so that it fails to undergo a conformational change upon the binding of its ligand.
B)The G protein-coupled receptor might carry a mutation that affects the receptor's transmembrane portion.
C)These cells might carry mutations in the downstream signaling pathway associated with this G protein-coupled receptor.
D)All of these choices are correct.

Question

Quizplus · Accepted Answer

All of these choices are possible explanations for why a ligand binding to a G protein-coupled receptor may not result in a response. The receptor may carry a mutation that prevents its conformational change or affects its transmembrane domain, or there may be mutations downstream in the signaling pathway. Therefore, it is difficult to say which is the best choice without further information.

A Researcher Is Studying a G Protein-Coupled Receptor in Eukaryotic