This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
If there is a Gs alpha subunit gain-of function mutation, this results in 
Select and explain. 
A. Decreased cAMP, B. Decreased IP, C. Increassed GTPase activity, D. Increased cAMP
D: Increased cAMP
Answer: D: Increased cAMP 
Explanation: The Gs alpha subunit (Gas, Gsa) is a subunit of the heterotrimeric G protein Gs that stimulates the cAMP-dependent pathway by activating adenylyl cyclase. Gsa is a GTPase that functions as a cellular signaling protein Ref-Harper 28/e p447