Dermatan sulfate epimerase 1 and dermatan 4- O-sulfotransferase 1 form complexes that generate long epimerized 4- O-sulfated blocks

J Biol Chem. 2018 Aug 31;293(35):13725-13735. doi: 10.1074/jbc.RA118.003875. Epub 2018 Jul 5.

Abstract

During the biosynthesis of chondroitin/dermatan sulfate (CS/DS), a variable fraction of glucuronic acid is converted to iduronic acid through the activities of two epimerases, dermatan sulfate epimerases 1 (DS-epi1) and 2 (DS-epi2). Previous in vitro studies indicated that without association with other enzymes, DS-epi1 activity produces structures that have only a few adjacent iduronic acid units. In vivo, concomitant with epimerization, dermatan 4-O-sulfotransferase 1 (D4ST1) sulfates the GalNAc adjacent to iduronic acid. This sulfation facilitates DS-epi1 activity and enables the formation of long blocks of sulfated iduronic acid-containing domains, which can be major components of CS/DS. In this report, we used recombinant enzymes to confirm the concerted action of DS-epi1 and D4ST1. Confocal microscopy revealed that these two enzymes colocalize to the Golgi, and FRET experiments indicated that they physically interact. Furthermore, FRET, immunoprecipitation, and cross-linking experiments also revealed that DS-epi1, DS-epi2, and D4ST1 form homomers and are all part of a hetero-oligomeric complex where D4ST1 directly interacts with DS-epi1, but not with DS-epi2. The cooperation of DS-epi1 with D4ST1 may therefore explain the processive mode of the formation of iduronic acid blocks. In conclusion, the iduronic acid-forming enzymes operate in complexes, similar to other enzymes active in glycosaminoglycan biosynthesis. This knowledge shed light on regulatory mechanisms controlling the biosynthesis of the structurally diverse CS/DS molecule.

Keywords: D4ST1; DS-epi1; DS-epi2; Golgi; chondroitin sulfate; dermatan sulfate; epimerase; epimerization; glycobiology; glycosaminoglycan.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigens, Neoplasm / analysis
  • Antigens, Neoplasm / metabolism*
  • COS Cells
  • Chlorocebus aethiops
  • DNA-Binding Proteins / analysis
  • DNA-Binding Proteins / metabolism*
  • Dermatan Sulfate / metabolism*
  • Humans
  • Iduronic Acid / metabolism*
  • Neoplasm Proteins / analysis
  • Neoplasm Proteins / metabolism*
  • Recombinant Proteins / analysis
  • Recombinant Proteins / metabolism
  • Sulfotransferases / analysis
  • Sulfotransferases / metabolism*

Substances

  • Antigens, Neoplasm
  • DNA-Binding Proteins
  • Neoplasm Proteins
  • Recombinant Proteins
  • Dermatan Sulfate
  • Iduronic Acid
  • Sulfotransferases
  • dermatan-4-sulfotransferase-1
  • DSE protein, human