glycocalyx abbr., GCX (rus. гликокаликс abbr., ГЛК) — carbohydrate-rich peripheral zone of the external surface coating of the membrane in most eukaryotic cells.

Description

The outer surface of cells is covered with lipopolysaccharide "hairs" consisting of proteoglycans, glycoproteins and glycolipids, which are called “glycocalyx” (see Fig.). Carbohydrate components of the glycocalyx include both compounds covalently bound to proteins or, to a lesser extent, to lipids on the cell surface, and additional glycoproteins and polysaccharides which are non-covalently attached to them. Some of the adsorbed macromolecules are components of the extracellular matrix, which makes it difficult to distinguish between such matrices and the glycocalyx with the cell membrane. In microvessels the endothelial cell glycocalyx has the size of 400-500 nm and occupies 10-20% of the vascular volume. Glycocalyx is considered as a protective layer on the vessel wall against pathogenic effects, a network barrier to the movement of molecules, and a porous hydrodynamic element of intercellular interaction (for example, between the endothelium of the vascular wall and the blood cells). Destruction of the glycocalyx often becomes one of the first signs of cell destruction with formation of nano-sized fragments (oligomers glycosaminoglycans products of limited proteolysis of glycoproteins, etc.) characterised by diverse biological activity, sometimes with very different scopes, depending on the size of the resulting molecules / nanoparticles. It is assumed that the endothelial glycocalyx has a definite ultrastructure and may be connected with the cytoskeleton (Fig.) to serve as a mechanochemical transducer of blood flow effects (shear stress) into other processes of cell signaling. Studying of cell glycocalyx and its fragments contributes to the development of nanopharmacology and early diagnostics of pathological lesions.

Illustrations

A symbolic representation of a glycocalyx chain attached to a cytoskeleton. 
 

A symbolic representation of a glycocalyx chain attached to a cytoskeleton.

 


Author

  • Maksimenko Alexander V.

Sources

  1. Squire J.M., Chew M., Nneji G. et al. Quasi-periodic substructure in the microvessel endothelial glycocalyx: a possible explanation for molecular filtering? // J. Struc. Biol. 2001. V. 136. P. 239–255.
  2. Jan Koolman, Klaus-Heinrich Röhm, Taschenatlas der Biochemie. 207 Farbtafeln von Jurgen Wirth 2., uberarbeitete und erweiterte Auflage 1998 Georg Thieme Verlag Stuttgart • New York.
  3. Weinbaum S., Tarbell J .M., Damiano E. R. The structure and function of the endothelial glycocalyx layer // Annu. Rev. Biomed. Eng. 2007. V. 9. P. 121–187.
  4. Albert L. Lehninger Principles of Biochemistry. W.H.: Freeman, 2008. - 1100 pp.
  5. Maksimenko A. V., Turashev A. D. Glycocalyx and its fragments in the functioning of the microcirculation (in Russian) // Regionarnoe krovoobrashhenie i mikrocirkuljacija. 2009. V. 8, No3.

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