What is the second messenger produced by adenylyl cyclase?

Adenylyl cyclase is an enzyme that converts ATP into cyclic adenosine monophosphate (cAMP), which is a critical second messenger in various signaling pathways. When a signaling molecule binds to a receptor on the cell surface, it often activates G-proteins that can then stimulate adenylyl cyclase to produce cAMP. This molecule plays a key role in transmitting signals within the cell, leading to various biological responses such as the activation of protein kinase A, ultimately affecting many physiological processes like metabolism, gene expression, and memory formation.

In contrast, inositol trisphosphate (IP3) and diacylglycerol (DAG) are products of the phospholipase C pathway and serve as second messengers related to different signaling cascades. cGMP, on the other hand, is primarily produced by guanylyl cyclase and acts as a second messenger in distinct pathways related to vascular smooth muscle relaxation, among other functions. Thus, cAMP is the correct answer as it directly results from the activity of adenylyl cyclase.