InterPro domain: IPR001054

Guanylate cyclases ( 4.6.1.2 ) catalyse the formation of cyclic GMP (cGMP) from GTP. cGMP acts as an intracellular messenger, activating cGMP-dependent kinases and regulating cGMP-sensitive ion channels. The role of cGMP as a second messenger in vascular smooth muscle relaxation and retinal photo-transduction is well established. Guanylate cyclase is found both in thesoluble and particulate fractions of eukaryotic cells. The soluble and plasmamembrane-bound forms differ in structure, regulation and other properties [ 1 , 2 , 3 , 4 ]. Most currently known plasma membrane-boundforms are receptors for small polypeptides. The soluble forms of guanylate cyclase arecytoplasmic heterodimers having alpha and beta subunits.

In all characterised eukaryote guanylyl- and adenylyl cyclases, cyclic nucleotide synthesis is carried out by the conserved class III cyclase domain.

1. Guanylyl cyclase-linked receptors. Annu. Rev. Neurosci. 15, 193-225
2. Guanylyl cyclase receptors and their endocrine, paracrine, and autocrine ligands. Cell 71, 1-4
3. Guanylyl cyclases, a growing family of signal-transducing enzymes. FASEB J. 5, 2785-91
4. The guanylyl cyclase receptor family. New Biol. 2, 499-504