Guanylin
Script error: No such module "Infobox".Template:Template otherScript error: No such module "Check for unknown parameters". Template:Pfam box Guanylin is a 15 amino acid peptide that is secreted by goblet cells in the colon. Guanylin acts as an agonist of the guanylyl cyclase receptor GC-C and regulates electrolyte and water transport in intestinal and renal epithelia.[1][2] Upon receptor binding, guanylin increases the intracellular concentration of cGMP, induces chloride secretion and decreases intestinal fluid absorption, ultimately causing diarrhoea.[3] The peptide stimulates the enzyme through the same receptor binding region as the heat-stable enterotoxins.[2]
Researches have found that a loss in guanylin expression can lead to colorectal cancer due to guanylyl cyclase C's function as an intestinal tumor suppressor.[4] When guanylin expression was measured on over 250 colon cancer patients, more than 85% of patients had a loss of guanylin expression in cancerous tissue samples by 100-1000 times when compared to the same patients's nearby healthy colon tissue.[4] Another study done on genetically engineered mice found that mice on a high calorie diet had reduced guanylin expression in the colon.[5] This loss of expression then resulted in guanylyl cyclase C inhibition and the formation of tumors, therefore linking diet-induced obesity with colorectal cancer. [5]
Human proteins containing this domain
Structure
This peptide has two topogies,[6] both isoforms are shown below:
References
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