Mucinelor

Mucinelor, commonly known as mucins, are high-molecular-weight glycoproteins produced by epithelial tissues. They are the main constituents of mucus, a hydrated gel that coats mucosal surfaces to provide lubrication, hydration and a barrier against pathogens.

Mucins are classified as secreted gel-forming mucins and membrane-tethered mucins. Secreted mucins such as MUC2, MUC5AC and MUC5B form viscoelastic networks that trap microbes and particulates, while MUC6 is expressed in the stomach. Membrane-associated mucins, including MUC1, MUC4 and MUC16, are attached to the cell surface and participate in signaling and protection of the epithelial barrier. The proteins are characterized by extensive O-glycosylation of tandem repeat regions rich in serine and threonine, giving mucins a highly hydrated, charged, and gel-forming structure.

Functionally, mucins provide lubrication, moisture retention and a physical barrier to pathogens, while their glycan coatings can modulate microbial communities and immune responses. Their expression and glycosylation patterns are tightly regulated and tissue-specific.

Alterations in mucin production or glycosylation are linked to disease. In the airways and lungs, imbalances can affect mucus viscosity; in the gastrointestinal tract, MUC2 is essential for mucus layering; and changes in mucin expression are observed in various cancers, where mucin profiles aid diagnosis and may influence tumor behavior.

Mucins are also explored as targets for therapy and as components of mucin-based biomaterials for drug delivery and tissue engineering.