Glycome Atlas
protein
Also known as mucin-2, intestinal mucin, MUC2 mucin
Plain-language answer
MUC2 is the main mucin that builds the mucus lining of the intestines. Goblet cells in the gut wall make and release it, and once outside the cell it swells and links together into the gel that forms the intestinal mucus layer. It is by far the most abundant gel-forming mucin in the colon.1
Because MUC2 forms the bulk of intestinal mucus, it is central to keeping gut bacteria away from the intestinal wall. When MUC2 is missing or poorly made, the protective inner layer breaks down, bacteria reach the epithelium, and inflammation can follow, which is why MUC2 is closely tied to gut barrier health.1
Technical detail
MUC2, encoded by the MUC2 gene and secreted by intestinal goblet cells, is the principal gel-forming mucin of the gut whose densely O-glycosylated central tandem-repeat domain and terminal cysteine-rich von Willebrand factor-like domains drive disulfide-mediated oligomerization into the structural network of the intestinal mucus barrier.1
MUC2 is synthesized by goblet cells and dimerizes through C-terminal cysteine-rich domains in the endoplasmic reticulum. Its central proline, threonine, and serine-rich tandem repeats are then extensively decorated with O-glycans in the Golgi, and N-terminal domains mediate further trimerization, producing large net-like polymers that are packaged and stored before regulated secretion.1
Upon release, MUC2 polymers hydrate and expand many-fold to build the intestinal mucus layer. In the colon this yields a stratified, largely bacteria-free inner layer attached to the epithelium and a looser outer layer that microbes colonize, so MUC2 quantity and glycosylation directly set the thickness and permeability of the protective barrier.1
Human relevance
Deficient or defective MUC2 is mechanistically linked to a penetrable colonic mucus layer and spontaneous colitis in experimental models, and reduced or altered MUC2-based mucus is described in ulcerative colitis.1
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