glykokalix

Glykokalix, often referred to in English as the glycocalyx, is a carbohydrate-rich layer that coats the exterior of many eukaryotic cell membranes and some prokaryotes. It is composed primarily of glycoproteins, proteoglycans, glycosaminoglycans, glycolipids, and, in mucus-secreting cells, mucins. The layer sits just outside the plasma membrane, frequently blending with the extracellular matrix, and its thickness and composition vary among cell types and conditions.

The glycocalyx serves multiple roles. It provides a protective barrier against mechanical and chemical stress, mediates cell–cell and cell–matrix interactions, and participates in cell signaling and recognition through carbohydrate-binding proteins such as lectins. In the immune system, it can influence pathogen binding and leukocyte trafficking. In the vascular system, the endothelial glycocalyx contributes to vascular permeability and anticoagulant properties, and its disruption is associated with inflammation and thrombosis.

Variations exist between kingdoms. In bacteria, the glycocalyx refers to a capsule (a well-defined, tightly attached layer) or a slime layer (a looser, diffuse coating). Capsules often enhance virulence by resisting phagocytosis.

Clinical and research relevance: alterations in glycocalyx composition or integrity are linked to processes such as cancer progression, inflammation, and atherosclerosis. The glycocalyx is studied as a factor in cell adhesion, signaling, and as a potential target for biomaterials, drug delivery, and diagnostic approaches.