MUC6

MUC6 is a gene that encodes mucin-6, a high molecular weight, secreted gel-forming mucin of the mucin family. In humans, MUC6 is mainly expressed by glandular cells of the stomach, particularly in the antral and pyloric mucosa, contributing to the mucous layer that protects the gastric epithelium.

Mucin-6 is a secreted glycoprotein characterized by a central tandem repeat domain rich in serine, threonine and proline, which undergo extensive O-glycosylation. The N- and C-terminal regions mediate polymerization and association with other gel-forming mucins, such as MUC5AC, enabling formation of a viscoelastic mucus gel that coats the gastric mucosa.

Its primary role is to augment the protective mucus barrier, providing lubrication and trapping of microbes and chemical irritants, thus reducing mucosal injury from gastric acid and digestive enzymes.

Alterations in MUC6 expression or glycosylation have been reported in gastric inflammatory conditions and neoplasia. In some gastric cancers, MUC6 expression persists and can aid histopathological characterization of tumors and their metaplastic backgrounds. Immunohistochemical detection of MUC6 is used in diagnostic pathology to differentiate gastric from intestinal-type mucosa in metaplastic lesions.

Like other mucins, MUC6 displays polymorphic VNTR regions in its mucin domain, contributing to size variation among individuals. The gene is part of a larger family of mucins that maintain the protective mucosal barrier throughout the gastrointestinal tract.

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