CGMP

cGMP (or 3'-5'-cyclic GMP[?]) is a second messenger molecule, used for intracellular signal transduction. It is made from GTP[?] by guanylate cyclase[?]. Its main purpose is the regulation of protein kinases; it is also use to regulate the passage of cations (for example, Ca²⁺)through ion channels, a mechanism used in retina cells by mammals.