Question

Describe the activation and inactivation of a G-protein.Follow the action of a G-protein-linked receptor through activation of adenylate cyclase to cell response.

Answer 1

Ans) The binding of the primary ligand will induce conformational change in the G protein coupled receptor (GPCR) and the GPCR gets activated which inturn activated the G protein by exchanging the GDP to GTP. Once the G protein is bound with GTP, the G-alpha subunit-GTP dissociates from the G-beta-gamma subunit and binds to the effector like adenylyl cyclase.Adenylyl cyclase will convert AMP to cAMP.Increase in the cAMP concentration will activate the PKA (Protein kinase A) which then activates the CREB Protein (cAMP response element binding protein) which enters the nucleus to turn ON the cell cycle.