glikokalix

Glikokalix, more commonly spelled glycocalyx in English, refers to a carbohydrate-rich layer that coats the exterior of many cells. It is composed of glycoproteins, proteoglycans, glycolipids, and associated polysaccharides. In bacteria the term can describe a capsule or slime layer that forms a protective and adhesive envelope, often important for virulence and biofilm formation.

In eukaryotic cells the glycocalyx is a dynamic, sugar-rich coat anchored to the plasma membrane by transmembrane proteins and glycolipids. Its thickness and composition vary by cell type and physiological state. The layer is synthesized in the endoplasmic reticulum and Golgi apparatus, then trafficked to the cell surface or secreted into the extracellular space.

Functions include protection against mechanical damage and desiccation, reduction of shear stress, lubrication in mucosal surfaces, and mediation of cell–cell and cell–matrix interactions. The glycocalyx participates in recognition by lectins, modulates immune responses, and contributes to signal transduction. In blood vessels, endothelial glycocalyx components such as heparan sulfate regulate vascular permeability and mechanotransduction.

Clinical relevance: changes in glycocalyx composition or shedding of its components are linked to disorders such as diabetes mellitus, atherosclerosis, and sepsis, where endothelial function can be impaired.

Etymology: the name derives from Greek glykys (sweet) and kalux (cup, cover), reflecting its sugary surface coating.