Composition and functional role of the mucus layers in the intestine
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In discussions on intestinal protection, the protective capacity of mucus has not been very much considered. The progress in the last years in understanding the molecular nature of mucins, the main building blocks of mucus, has, however, changed this. The intestinal enterocytes have their apical surfaces covered by transmembrane mucins and the whole intestinal surface is further covered by mucus, built around the gel-forming mucin MUC2. The mucus of the small intestine has only one layer, whereas the large intestine has a two-layered mucus where the inner, attached layer has a protective function for the intestine, as it is impermeable to the luminal bacteria.
KeywordsMucus Mucin MUC2 Colon Commensal bacteria Small intestine
This work was supported by the Swedish Research Council (no. 7461, 21027, and 342-2004-4434), The Swedish Cancer Foundation, The Knut and Alice Wallenberg Foundation (KAW2007.0118), IngaBritt and Arne Lundberg Foundation, Sahlgren’s University Hospital (LUA-ALF), EU-FP7 IBDase (no. 200931), Wilhelm and Martina Lundgren’s Foundation, Torsten och Ragnar Söderbergs Stiftelser, The Sahlgrenska Academy Foundations, and The Swedish Foundation for Strategic Research—The Mucosal Immunobiology and Vaccine Center (MIVAC) and the Mucus-Bacteria-Colitis Center (MBC) of the Innate Immunity Program (2010-2014). We also acknowledge the Mammalian Protein Expression Core Facility at the University of Gothenburg.
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