Question

On the cytoplasmic site of GCPRs, the G-proteins bind to ___________________

(a) amino-terminus

(b) promoter region

(c) second loop

(d) third loop

I had been asked this question at a job interview.

Query is from Cell Signaling and Signal Transduction topic in chapter Cell Signaling and Signal Transduction of Cell Biology

Answer 1

The correct answer is (d) third loop

Explanation: There are 3 loops of G-protein coupled receptor located on the outside of the cell and 3 loops located on the cytoplasmic site. The G-proteins bind to the third intracellular loop while the loops located outside the cell form the ligand-binding active site.