Receptors for natriuretic peptides

Receptors for natriuretic peptides

Receptors for natriuretic peptides: The natriuretic peptides are the A type, B type, C type and the D type. There are two groups of receptors for the natriuretic peptides: guanylyl cyclase receptors which lead to the formation of cyclic guanosyl monophosphate (cGMP) and the natriuretic peptide clearance receptors. Of the former, two receptors – A and B have been identified. Natriuretic peptide receptor A (NPR-C) and natriuretic peptide receptor B (NPR-B) are linked to the cyclic GMP signaling cascade. Natriuretic peptide receptor A binds to both ANP (atrial natriuretic peptide) and BNP (brain type natriuretic peptide). C type natriuretic peptide (CNP) binds to the B type natriuretic peptide receptor (NPR-B). The predominant receptors in the blood vessels are of the A type, while the B type receptors predominate in the brain. When the natriuretic peptides bind to their receptors, guanylyl cyclase is activated, which in turn leads to elevation of intracellular cyclic GMP. cGMP is an important intracellular signaling molecule. Natriuretic peptide receptor C (NPR-C) is a clearance receptor. NPR-C is devoid of guanylyl cyclase activity. NPR-C is the most abundant type of natriuretic peptide receptor and all the three types of natriuretic peptides bind to NPR-C, though the affinity is most for ANP and least for BNP, with that of CNP in between. Once the natriuretic peptide binds to NPR-C, the complex is internalised and enzymatically degraded. The receptor then (NPR-C) then returns to the cell surface for binding further peptides. NPR-C has a G protein activating sequence in its 37 amino acid cytoplasmic domain.
NPR-A is also known as NPR-1. Still another name is guanylyl cyclase A (GC-A). Similarly, NPR-B is also known as GC-B [Mol Cell Biochem. 2002;230:31-47]. GC-A has a role in the regulation of blood pressure and cardiac and renal functions. GC-B has a structure and regulation which is similar to GC-A.