Second messenger system

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In biochemistry and signal transduction, a second messenger system are "Systems in which an intracellular signal is generated in response to an intercellular primary messenger such as a hormone or neurotransmitter. They are intermediate signals in cellular processes such as metabolism, secretion, contraction, phototransduction, and cell growth. Examples of second messenger systems are the adenyl cyclase-cyclic AMP system, the phosphatidylinositol diphosphate-inositol triphosphate system, and the cyclic GMP system"^[1]

In signal transduction, cell surface receptors may activate second messenger systems such as adenyl cyclase-cyclic AMP and cyclic GMP which then may activate protein kinases which then affect downstream targets (see figure).^[2]

References

1. ↑ Anonymous, (2009) Second messenger system (English). Medical Subject Headings. U.S. National Library of Medicine.
2. ↑ Lodish, Harvey F. (1999). “20.1. Overview of Extracellular Signaling”, Molecular cell biology. New York: Scientific American Books. ISBN 0-7167-3136-3.