Cyclic Guanosine Monophosphate (cGMP)

cGMP is a multi-functional second messenger molecule. It is generated via two pathways distinguished by the types of Guanylyl Cyclase (GC) that mediate its conversion from guanosine triphosphate (GTP). In the soluble pathway, cGMP is generated via cytoplasmic nitric oxide (NO)-activated GC. GCs in the particulate pathway share some homology with those activated by NO but are transmembrane proteins with extracellular ligand-binding domains. The ligands for a subset of membrane GCs are members of the Natriuretic Peptide (NP) hormone family including Atrial NP hormone,B-type NP hormone, and C-type NP hormone.cGMP primarily affects cellular activities through four different pathways. These include cGMP-dependent Protein Kinases (PKG/GK), cyclic nucleotide-gated (CNG) channels, cAMP-dependent Protein Kinase (PKA), and Phosphodiesterases.PKGs (PKG I and PKG II) are serine/threonine kinases activated by cGMP.