Heparan Sulfate 6-Sulfotransferase
The carbohydrate backbone in heparan sulfate (HS) and heparin is composed of HexA-GlcNAc/GlcNSO3 repeating unit in which HexA is either D-GlcA or L-IdoA. Sulfate groups are present on the various positions of the repeating units: position 2 of HexA, position 6 of GlcNAc/GlcNSO3, and position 3 of GlcNAc/GlcNSO3. Heparan sulfate 6-O-sulfotransferase (HS6ST) transfers sulfate to position 6 of the N-sulfated glucosamine residue in HS and heparin. HS6STs serve as enzymes catalyzing the final modification step for the formation of the IdoA/IdoA(2SO4)-GlcNSO3(6SO4) unit and the GlcA-GlcNSO3(6SO4) unit in HS and heparin. HS chains in heparan sulfate proteoglycans (HSPGs) are known to interact with a variety of proteins, such as heparin- binding growth factors, extracellular matrix components, protease inhibitors, proteases, and lipoprotein lipase. As described in Chapter 67, these interactions are implicated not only in various dynamic cellular behaviors such as cell proliferation, cell differentiation, cell adhesion, cell migration, and cell morphology but also in various physiological phenomena such as inflammation, blood coagulation, and tumor cell invasion and malignancy. Moreover, infections of host cells with some living pathogens such as viruses and parasites have been shown to occur through the interactions with cell surface HSs on host cells. The interactions of HS with such various ligands seem to be mediated by particular regions of HS chains where the 6- O-sulfated sugar residues play important roles as factors to determine their specific structures (Ashikari et al. 1995).
KeywordsHepatocyte Growth Factor Heparan Sulfate Chinese Hamster Ovary Cell Heparan Sulfate Chain Hexuronic Acid
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