Gastric mucus glycoproteins (MUC)

Gastric mucus glycoproteins, primarily Mucin-5AC (MUC5AC) and Mucin-6 (MUC6), are high-molecular-weight glycoproteins that constitute the primary structural component of the gastric mucus gel layer (UniProt P98088; UniProt Q6W4X9). This layer serves as a critical physiological barrier, protecting the underlying gastric epithelium from the corrosive effects of hydrochloric acid and the proteolytic activity of pepsin (StatPearls: Physiology, Gastrointestinal). MUC5AC is predominantly expressed by surface mucous cells, while MUC6 is localized to the mucous neck cells of the gastric glands, creating a stratified defense system (PubMed: 15673989). In diseases such as peptic ulcer disease, gastritis, and Helicobacter pylori infection, this mucosal barrier is often degraded or its synthesis is impaired, leading to tissue damage (NIH: Gastric Mucosal Barrier). Therapeutic agents like sucralfate and rebamipide target these glycoproteins by either binding to them to reinforce the physical barrier or by stimulating their secretion via prostaglandin-dependent pathways (FDA Label: Carafate; PubMed: 24570952). These interactions are vital for promoting the healing of gastric lesions and maintaining mucosal integrity against both endogenous and exogenous stressors. Additionally, surface proteins such as trefoil factor family (TFF) peptides interact with these mucins to stabilize the gel and promote epithelial repair (PubMed: 12033438).

Other names

Gastric mucinsGastric mucosal surface proteinsMucin-5ACMucin-6Gastric mucus barrier

Drugs interact with these glycoproteins by forming protective polyanionic complexes at ulcer sites, stimulating increased synthesis and secretion of mucins, or enhancing the viscosity and hydrophobicity of the mucus gel layer (StatPearls: Sucralfate; PubMed: 24570952).