MUC2

MUC2 encodes the major gel-forming mucin produced by intestinal goblet cells and constitutes the structural backbone of the gastrointestinal mucus barrier, where it physically separates luminal microorganisms from the epithelial surface and supports mucosal homeostasis^[4][5]. Mechanistically, MUC2 polymers form highly organized mucus networks that generate the characteristic inner and outer colonic mucus layers, thereby regulating microbial access, antigen exposure, and host defense responses^[1][2]. Through these barrier functions, MUC2 contributes to intestinal immune regulation and maintenance of a stable microbiota, while defective synthesis, secretion, or organization of MUC2 compromises barrier integrity and promotes epithelial contact with bacteria^[5][6]. In disease settings, dysregulated MUC2 production has been closely associated with inflammatory bowel disease and chronic intestinal inflammation, and experimental studies demonstrate that impairment of the MUC2 barrier increases susceptibility to colitis and inflammation-related pathology^[2][6][3]. Compared with related membrane-associated mucins such as MUC1, MUC3, and MUC17, MUC2 is distinguished by its role as a secreted polymeric mucin that forms the bulk extracellular mucus scaffold rather than functioning primarily at the epithelial cell surface^[3]. For experimental applications, MUC2 serves as a widely used biomarker of goblet cell differentiation, mucus barrier integrity, and host-microbiota interactions, making it a valuable target for studies investigating intestinal barrier dysfunction, mucosal immunity, and therapeutic strategies aimed at restoring mucus homeostasis^[4][6].