Signaling of GPCRs (G-protein coupled receptors) is terminated by which mechanism?

A. Phosphorylation of receptors by cAMP (cyclic adenosine monophosphate) activated PKA (protein kinase A), which blocks the interaction with G-protein

B. Cleavage of the GPCRs by receptor-specific serine or threonine proteases

C. Hydrolysis of GTP (guanosine triphosphate) to GDP (guonosine diphosphate) by G-protein α.

D. None of the above

E. All of the above

Answer: G protein coupled receptors signalling is terminated by phosphorylation of receptors by cyclic adenosine monophosphate activated protein kinase which blocks the interaction with G protein.

Explanation:

G protein coupled receptors (GPCR) signalling constitute a large protein family that detect molecules outside the cell and signal transduction internally and allow responses. They are majorly found in eukaryotes like yeast. The signalling of GPCR by G protein is terminated by phosphorylation of active receptor by GCPR kinases and protein kinase and also the binding of arrestin proteins.