Glycocalyx

Glycocalyx is a general term referring to extracellular polymeric material (glycoprotein) produced by some bacteria, epithelia and other cells. For instance, the slime on the outside of a fish is considered to be a glycocalyx. The term was initially applied to the polysaccharide matrix excreted by epithelial cells forming a coating on the surface of epithelial tissue, but its functions have been discovered to go well beyond that. Most animal epithelial cells have a fuzzy coat called the glycocalyx on the external surface of its plasma membrane. This coating consists of several carbohydrate moieties of membrane glycolipids and glycoproteins, which serve as backbone molecules for support. Further research has shown that the glycocalyx, which is located on the apical surface of endothelial cells, is composed of a negatively charged network of proteoglycans, glycoproteins, and glycolipids. Generally, the carbohydrate portion of the glycolipids found on the surface of plasma membranes helps these molecules contribute to cell-cell recognition, communication, and intracellular adhesion.