Mucini

Mucini is not a standard term in contemporary biology. It may appear in older texts or in certain linguistic contexts as a variant of mucin, the glycoprotein family that constitutes mucus. In current usage, the plural form mucins is preferred for scientific clarity.

Mucins are high-molecular-weight glycoproteins produced by goblet cells and mucous glands in epithelia throughout the body. They are heavily glycosylated, with extensive carbohydrate chains that give mucus its gel-like properties, hydration, and protective function. Mucins contribute to lubrication of surfaces and act as a barrier against mechanical damage, pathogens, and chemical irritants. They also participate in cell signaling and immune modulation.

There are two broad classes of mucins: secreted gel-forming mucins, which form the mucus gel (examples include MUC2, MUC5AC, MUC5B in humans); and membrane-bound mucins, which span the cell membrane and participate in signaling and cell–cell interactions (such as MUC1, MUC4, MUC16). The human genome encodes a large family of MUC genes, with tissue-specific expression patterns.

Physiological roles of mucins include protection of mucosal surfaces, maintenance of hydration, and involvement in host defense and tissue repair. Dysregulation of mucin production or expression is associated with various diseases, including chronic respiratory conditions with mucus hypersecretion, inflammatory bowel diseases, and certain cancers where mucin genes, particularly MUC1, are overexpressed or aberrantly glycosylated.

Research on mucins employs methods such as immunohistochemistry, biochemical assays for soluble mucins, and genetic analyses of MUC genes. Etymologically, the term derives from mucus; for modern scientific writing, mucins is the preferred term and mucini is rarely used.