General Description
The gene guanylate cyclase activator 2A (GUCA2A) is mapped to human chromosome 1p35-p34. GUCA2A mRNA is mainly detected in the gastrointestinal tract and kidney.
Biochem/physiol Actions
Guanylate cyclase activator 2A (GUCA2A) is mainly an intestinal peptide hormone and endogenous ligand of guanylyl cyclase C. It is produced as prohormone proguanylin. In the intestine, GUCA2A along with guanylate cyclase C receptor activates epithelial cells. Activation of this pathway results in secretion of Cl- and HCO3- and inhibition of Na+ absorption, which drives water secretion into the intestinal lumen. In the renal tissue GUCA2A elicits natriuresis, kaliuresis, and diuresis, along with increasing urinary cyclic guanosine monophosphate (cGMP) levels. GUCA2A is suggested to elevate the exrection of urinary salt and water, which results in the prevention of hypernatremia and hypervolemia following increased salt uptake by the body. The protein is also expressed in epithelial cells of the ductal system of human parotid and submandibular glands. It is released into the saliva through salivary duct cells. GUCA2A is highly expressed in salivary gland tumors. On the other hand, GUCA2A is down-regulated in colorectal cancer.
