Secondary Messenger

Definition

Secondary messengers are molecules that relay signals received at receptors on the cell surface — such as the arrival of protein hormones, growth factors, etc. — to target molecules in the cytosol and/or nucleus.

Related terms

cAMP (Cyclic Adenosine Monophosphate): A common secondary messenger in cells that is derived from ATP and used for intracellular signal transduction.

G-Protein Coupled Receptors: These are cell surface receptors that work with the help of a G protein; they activate secondary messengers when a ligand binds to them.

Signal Transduction:

The process by which a chemical or physical signal is transmitted through a cell via a series of molecular events.