Recombinant Human Mucin-2 (MUC2), partial

Function

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 (PubMed:17058067, PubMed:19432394, PubMed:33031746). Major constituent of the colon mucus, which is mainly formed by large polymeric networks of MUC2 secreted by goblet cells that cover the exposed surfaces of intestine (PubMed:19432394, PubMed:33031746). MUC2 networks form hydrogels that guard the underlying epithelium from pathogens and other hazardous matter entering from the outside world, while permitting nutrient absorption and gas exchange (PubMed:33031746, PubMed:36206754). Acts as a divalent copper chaperone that protects intestinal cells from copper toxicity and facilitates nutritional copper unptake into cells (PubMed:36206754). Binds both Cu(2+) and its reduced form, Cu(1+), at two juxtaposed binding sites: Cu(2+), once reduced to Cu(1+) by vitamin C (ascorbate) or other dietary antioxidants, transits to the other binding site (PubMed:36206754). MUC2-bound Cu(1+) is protected from oxidation in aerobic environments, and can be released for nutritional delivery to cells (PubMed:36206754). Mucin gels store antimicrobial molecules that participate in innate immunity (PubMed:33031746). Mucin glycoproteins also house and feed the microbiome, lubricate tissue surfaces, and may facilitate the removal of contaminants and waste products from the body (PubMed:33031746). Goblet cells synthesize two forms of MUC2 mucin that differ in branched chain O-glycosylation and the site of production in the colon: a (1) 'thick' mucus that wraps the microbiota to form fecal pellets is produced in the proximal, ascending colon (By similarity). 'Thick' mucus transits along the descending colon and is lubricated by a (2) 'thin' MUC2 mucus produced in the distal colon which adheres to the 'thick' mucus (By similarity)

Subcellular Location

Secreted

Tissue Specificity

Colon, small intestine, colonic tumors, bronchus, cervix and gall bladder

Subunit

(Microbial infection) Interacts in vitro with L.monocytogenes internalin proteins InlB, InlC and InlJ; for InlC binding is slightly better at pH 5.5, (the pH of the intestine) than at pH 7.4

• Gum J.R. Jr. et al. Molecular cloning of human intestinal mucin (MUC2) cDNA. Identification of the amino terminus and overall sequence similarity to prepro-von Willebrand factor. — J. Biol. Chem. (1994)
• Taylor T.D. et al. Human chromosome 11 DNA sequence and analysis including novel gene identification. — Nature (2006)
• Gum J.R. Jr. et al. The human MUC2 intestinal mucin has cysteine-rich subdomains located both upstream and downstream of its central repetitive region. — J. Biol. Chem. (1992)
• Toribara N.W. et al. MUC-2 human small intestinal mucin gene structure. Repeated arrays and polymorphism. — J. Clin. Invest. (1991)
• Gum J.R. Jr. et al. Molecular cloning of human intestinal mucin cDNAs. Sequence analysis and evidence for genetic polymorphism. — J. Biol. Chem. (1989)
• Xu G. et al. Human intestinal mucin-like protein (MLP) is homologous with rat MLP in the C-terminal region, and is encoded by a gene on chromosome 11 p 15.5. — Biochem. Biophys. Res. Commun. (1992)
• Silverman H.S. et al. In vivo glycosylation of mucin tandem repeats. — Glycobiology (2001)
• Godl K. et al. The N terminus of the MUC2 mucin forms trimers that are held together within a trypsin-resistant core fragment. — J. Biol. Chem. (2002)