What effect does activation of adenylyl cyclase have on cAMP levels?

Activation of adenylyl cyclase significantly increases cAMP levels within a cell. Adenylyl cyclase is an enzyme that catalyzes the conversion of ATP (adenosine triphosphate) to cAMP (cyclic adenosine monophosphate). This process is a key step in many signal transduction pathways, particularly those involving G protein-coupled receptors (GPCRs). When a ligand binds to a GPCR, it can activate a specific G protein, which then stimulates adenylyl cyclase, resulting in higher concentrations of cAMP.

cAMP serves as a crucial second messenger that activates various protein kinases, particularly protein kinase A (PKA), thereby influencing a variety of cellular responses including metabolism, gene expression, and cell signaling. Therefore, by facilitating the production of cAMP, adenylyl cyclase plays an essential role in amplifying the cellular response to various stimuli, making the increase of cAMP levels a critical event in many physiological processes.