MUC2
Description
The MUC2 (mucin 2, oligomeric mucus/gel-forming) is a protein-coding gene located on chromosome 11.
Mucin 2, oligomeric mucus gel-forming, also known as MUC2, is a protein that in humans is encoded by the MUC2 gene. This gene encodes a member of the mucin protein family. The protein encoded by this gene, also called mucin 2, is secreted onto mucosal surfaces. Mucin 2 is particularly prominent in the gut where it is secreted from goblet cells in the epithelial lining into the lumen of the large intestine. There, mucin 2, along with small amounts of related-mucin proteins, polymerizes into a gel of which 80% by weight is oligosaccharide side-chains that are added as post-translational modifications to the mucin proteins. This gel provides an insoluble mucous barrier that serves to protect the intestinal epithelium. The mucin 2 protein features a central domain containing tandem repeats rich in threonine and proline that varies between 50 and 115 copies in different individuals. Alternatively spliced transcript variants of this gene have been described, but their full-length nature is not known.
MUC2 coats the epithelia of the intestines and other mucus membrane-containing organs to provide a protective, lubricating barrier against particles and infectious agents at mucosal surfaces. It is the major constituent of the colon mucus, which is formed by large polymeric networks of MUC2 secreted by goblet cells. These networks form hydrogels that protect the underlying epithelium from pathogens and other harmful substances, while allowing nutrient absorption and gas exchange. MUC2 also acts as a divalent copper chaperone, protecting intestinal cells from copper toxicity and facilitating nutritional copper uptake. It binds both Cu(2+) and its reduced form, Cu(1+), at two juxtaposed binding sites, protecting Cu(1+) from oxidation and releasing it for nutritional delivery to cells. Mucin gels store antimicrobial molecules, participate in innate immunity, house and feed the microbiome, lubricate tissue surfaces, and facilitate the removal of contaminants and waste products. Goblet cells synthesize two forms of MUC2 mucin, a 'thick' mucus that wraps the microbiota to form fecal pellets in the proximal, ascending colon, and a 'thin' mucus that lubricates the 'thick' mucus in the distal colon.
MUC2 is also known as MLP, MUC-2, SMUC.
