Guanylate cyclase activator 2B (GUCA2B)

Guanylate cyclase activator 2B (GUCA2B), also known as uroguanylin, is a peptide hormone primarily produced in the intestinal epithelium. It functions as an endogenous ligand for the guanylate cyclase-C (GC-C) receptor found on the luminal surface of intestinal epithelial cells. Upon binding to this receptor, GUCA2B stimulates the production of cyclic GMP (cGMP), which activates ion channels and leads to the secretion of chloride and bicarbonate ions and the inhibition of sodium absorption—ultimately regulating intestinal fluid and electrolyte homeostasis. This process is vital for normal digestive function and maintenance of mucosal barrier integrity. GUCA2B is proteolytically processed from a preproprotein and is structurally related to guanylin (GUCA2A), another regulator of intestinal ion transport. Expression changes and signaling disruptions involving GUCA2B and the guanylate cyclase-C pathway have been implicated in diseases such as inflammatory bowel disease and colorectal neoplasia.

Other names

Guanylate cyclase C-activating peptide 2UroguanylinGCAP-IIUGNGuanylate cyclase C-activating peptide IIprepro-uroguanylin

Binds to guanylate cyclase-C receptor (GUCY2C), activating the receptor’s intracellular catalytic domain, leading to increased cyclic GMP (cGMP) in target cells and downstream signaling that changes electrolyte/fluid secretion.