Sulfation of glucuronic acid in the linkage tetrasaccharide by HNK-1 sulfotransferase is an inhibitory signal for the expression of a chondroitin sulfate chain on thrombomodulin

Biochem Biophys Res Commun. 2011 Nov 11;415(1):109-13. doi: 10.1016/j.bbrc.2011.10.023. Epub 2011 Oct 12.

Abstract

HNK-1 (human natural killer-1) carbohydrate epitope (HSO(3)-3GlcAβ1-3Galβ1-4GlcNAc-) recognized by a HNK-1 monoclonal antibody is highly expressed in the nervous system and biosynthesized by a glucuronyltransferase (GlcAT-P or GlcAT-S), and sulfotransferase (HNK-1ST). A similar oligosaccharide (HSO(3)-3GlcAβ1-3Galβ1-3Galβ1-4Xyl) also recognized by the HNK-1 antibody had been found in a glycosaminoglycan (GAG)-protein linkage region of α-thrombomodulin (TM) from human urine. However, which sulfotransferase is involved in sulfation of the terminal GlcA in the GAG-protein linkage region remains unclear. In this study, using CHO-K1 cells in which neither GlcAT-P nor GlcAT-S is endogenously expressed, we found that HNK-1ST has the ability to produce HNK-1 immunoreactivity on α-TM. We also demonstrated that HNK-1ST caused the suppression of chondroitin sulfate (CS) synthesis on TM and a reduction of its anti-coagulant activity. Moreover, using an in vitro enzyme assay system, the HNK-1-positive TM was found not to be utilized as a substrate for CS-polymerizing enzymes (chondroitin synthase (ChSy) and chondroitin polymerizing factor (ChPF)). These results suggest that HNK-1ST is involved in 3-O-sulfation of the terminal GlcA of the linkage tetrasaccharide which acts as an inhibitory signal for the initiation of CS biosynthesis on TM.

MeSH terms

  • Animals
  • Carbohydrate Sequence
  • Cell Line
  • Chondroitin Sulfates / biosynthesis*
  • Chondroitin Sulfates / chemistry
  • Cricetinae
  • Cricetulus
  • Glucuronic Acid / metabolism*
  • Humans
  • Molecular Sequence Data
  • Oligosaccharides / chemistry
  • Oligosaccharides / metabolism*
  • Sulfates
  • Sulfotransferases / metabolism*
  • Thrombomodulin / chemistry
  • Thrombomodulin / metabolism*

Substances

  • HSO(3)-3GlcAbeta1-3Galbeta1-3Galbeta1-4Xyl
  • Oligosaccharides
  • Sulfates
  • Thrombomodulin
  • Glucuronic Acid
  • Chondroitin Sulfates
  • HNK-1 sulfotransferase
  • Sulfotransferases