Gastric mucin (MUC) (MUC)

Gastric mucins are high-molecular-weight glycoproteins that serve as the primary structural components of the gastric mucus-bicarbonate barrier, which is essential for protecting the stomach epithelium from the highly acidic environment and the proteolytic activity of pepsin [2][5]. The two dominant types in the human stomach are MUC5AC, primarily expressed by surface mucous cells, and MUC6, found in the deeper gastric glands [1]. These mucins form a complex, viscoelastic gel through the formation of disulfide bonds between cysteine-rich domains, creating a protective shield that also traps bicarbonate ions to maintain a near-neutral pH at the cell surface [5]. In conditions like peptic ulcer disease or Helicobacter pylori infection, the integrity and composition of this mucin layer are often compromised, leading to mucosal injury and inflammation [3]. Pharmacological intervention focuses on enhancing this barrier using cytoprotective agents like sucralfate or stimulating its production with prostaglandin analogs like misoprostol [4]. Additionally, the expression and glycosylation patterns of gastric mucins are frequently altered in gastric cancer, making them significant targets for diagnostic and therapeutic research [3].

Other names

Gastric mucusMucin-5ACMucin-6MUC5ACMUC6Gastric gel-forming mucinGastric mucus-bicarbonate barrier

Cytoprotective agents like sucralfate bind directly to the mucin-gel layer and exposed ulcer proteins to form a physical barrier against acid and pepsin [4]. Prostaglandin analogs and other secretagogues stimulate the synthesis and secretion of mucins from mucous cells to thicken the protective layer [2]. Mucolytics act by reducing the viscosity of the mucus through the cleavage of disulfide bonds that hold the mucin polymers together [5].