Proteoglycans function

Selleck SB Genetic dissection of proteoglycan function in Drosophila and C. elegans. Semin Cell DevBiol 2001 12 127. 

Proteoglycans resemble polysaccharides more than proteins in as much as the carbohydrate makes up as much as 95% of the hiomolecule hy weight. Proteoglycans function as lubricants and structural components in connective tissue, mediate adhesion of cells to the extracellular matrix, and bind factors that stimulate cell proliferation. 

R.V. lozzo. 1999. The biology of small leucine-rich proteoglycans Functional network of interactive proteins J. Biol. Chem. 274 18843-18846. (PubMed)... 

Nakato, El., and K. Kimata. 2002. Eleparan sulfate fine structure and specificity of proteoglycan functions. Biochim. Biophys. Acta 1573 312-318. 

Salmivirta, M. and Jalkanen, M. Syndecan family of cell surface proteoglycans developmentaUy regulated receptors for extracellular effector molecules. Experientia, 51, 863,1995. lozzo, R. V. The biology of the small leucine-rich proteoglycans. Functional network of interactive proteins. J Biol Chem, 274,18843,1999. 

FIGURE 9.32 Proteoglycans serve a variety of functions on the cytoplasmic and extracellular surfaces of the plasma membrane. Many of these functions appear to involve the binding of specific proteins to the glycosaminoglycan groups. 

Proteoglycans are also found in intracellular locations such as the nucleus their function in this organelle has not been elucidated. They are present in some storage or secretory granules, such as the chromaffin granules of the adrenal medulla. It has been posm-lated that they play a role in release of the contents of such granules. The various functions of GAGs are summarized in Table 48-8. 

GAGs occur in tissues bound to various proteins (hnker proteins and core proteins), constituting proteoglycans. These structures are often of very high molecular weight and serve many functions in tissues. 

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