Human pathology

Home page > A. Molecular pathology > proteoglycans

proteoglycans

Proteoglycans are specialized glycoproteins with heterogeneous structures that are found in all connective tissues and on cell surfaces.

Proteoglycans and hyaluronic acid (HA, hyaluronan or hyaluronate) make up the third type of component in the extracellualr matrix (ECM), besides the fibrous structural proteins and cell adhesion proteins.

Proteoglycans consist of a core protein linked to one or more polysaccharides called glycosaminoglycans (GAGs). These are long repeating polymers of specific disaccharides in which one (or both) contains a sulfate residue. Proteoglycans are remarkable in their diversity. A specific ECM may contain several different core proteins, each containing different GAGs.

Proteoglycans are named according to the structure of their principal repeating disaccharide. Some of the most common are heparan sulfate, chondroitin sulfate, and dermatan sulfate. They have diverse roles in regulating connective tissue structure and permeability. Proteoglycans can also be integral membrane proteins and, through their binding to other proteins and fibroblast growth factor, act as modulators of cell growth and differentiation.

Proteoglycans are assembled in the Golgi apparatus.

Types

- heparan sulphate proteoglycans
- basement membrane proteoglycans

Pathology

- proteoglycans defects

References

- Hacker U, Nybakken K, Perrimon N. Heparan sulphate proteoglycans: the sweet side of development. Nat Rev Mol Cell Biol. 2005 Jul;6(7):530-41. PMID: 16072037

- Hebert DN, Garman SC, Molinari M. The glycan code of the endoplasmic reticulum: asparagine-linked carbohydrates as protein maturation and quality-control tags. Trends Cell Biol. 2005 Jun 3; PMID: 15939591

- Selleck SB. Proteoglycans and pattern formation: sugar biochemistry meets developmental genetics. Trends Genet. 2000 May;16(5):206-12. PMID: 10782114