What is the function of cAMP in the signaling pathway initiated by the B2 adrenergic receptor?

cAMP, or cyclic adenosine monophosphate, serves as an important second messenger in the signaling pathway initiated by the B2 adrenergic receptor. When the B2 adrenergic receptor is activated by an agonist, it undergoes a conformational change that allows it to interact with the G protein, specifically Gs. This interaction activates Gs, leading to the stimulation of adenylyl cyclase, an enzyme responsible for the conversion of ATP to cAMP.

Once produced, cAMP activates protein kinase A (PKA) by binding to its regulatory subunits. This activation allows PKA to phosphorylate various target proteins, which leads to a range of cellular responses, including the modulation of enzyme activity, gene expression, and metabolic pathways. This key role of cAMP in activating PKA establishes it as a crucial mediator in the signaling cascade initiated by the B2 adrenergic receptor.

In contrast to the other options, cAMP does not bind directly to glucose, as glucose is not a target for cAMP's signaling action. It also does not deactivate GPCRs; rather, it functions to propagate the signal initiated by the receptor activation. Furthermore, cAMP does not hydrolyze ATP; instead, it