What is the Origin of cAMP Signaling?

The discovery of cAMP as a second messenger was pioneered by Earl Sutherland Jr. in the late 1950s and early 1960s, a breakthrough that fundamentally changed the understanding of hormone action. His work elucidated how hormones like adrenaline act on the cell surface but exert their influence through an internal chemical intermediary. The term 'cAMP signaling' refers to the entire cascade initiated by this nucleotide, originating from its synthesis by the enzyme adenylyl cyclase.

What is the Mechanism of cAMP Signaling?

The pathway begins when a hormone binds to a G protein-coupled receptor (GPCR) on the cell membrane, leading to the activation of the enzyme adenylyl cyclase. Adenylyl cyclase then catalyzes the conversion of adenosine triphosphate (ATP) into the second messenger, cAMP. Elevated intracellular cAMP levels subsequently activate protein kinase A (PKA), which phosphorylates specific target proteins within the cell. This phosphorylation ultimately triggers the cellular response, thereby linking the initial external hormonal stimulus to the final internal physiological action.

cAMP Signaling

Meaning

Cyclic adenosine monophosphate (cAMP) signaling is a ubiquitous intracellular transduction cascade crucial for mediating the effects of many hormones and neurotransmitters within the cell. This fundamental biochemical process translates an extracellular hormonal signal, which cannot cross the cell membrane, into a specific physiological response inside the target cell. As a classic second messenger system, cAMP plays a pivotal role in endocrinology, regulating diverse cellular functions from metabolism and secretion to gene expression.