Identification and characterization of CMP-NeuAc:GalNAc-IgA1 alpha2,6-sialyltransferase in IgA1-producing cells

Research output: Contribution to journalArticle

Abstract

Glycosylation defects occur in several human diseases. In IgA nephropathy, IgA1 contains O-glycans that are galactose-deficient and consist mostly of core 1 alpha2,6 sialylated N-acetylgalactosamine, a configuration suspected to prevent beta1,3 galactosylation. We confirmed the same aberrancy in IgA1 secreted by the human DAKIKI B cell line. Biochemical assays indicated CMP-NeuAc:GalNAc-IgA1 alpha2,6-sialyltransferase activity in this cell line. However, a candidate enzyme, ST6-GalNAcI, was not transcribed in DAKIKI cells, B cells isolated from blood, or Epstein-Barr virus (EBV)-immortalized IgA1-producing cells from the blood of IgAN patients and healthy controls. Instead, ST6-GalNAcII transcription was detected at a high level. Expression of the ST6-GalNAcII gene and activity of the CMP-NeuAc:GalNAc-IgA1 alpha2,6-sialyltransferase were higher in IgA1-producing cell lines from IgAN patients than in such cells from healthy controls. These data are the first evidence that human cells that lack ST6-GalNAcI can sialylate core 1 GalNAc-Ser/Thr.

Details

Authors
  • Milan Raska
  • Zina Moldoveanu
  • Hitoshi Suzuki
  • Rhubell Brown
  • Rose Kulhavy
  • Judit Andrasi
  • Stacy Hall
  • Huong L Vu
  • Fredric Carlsson
  • Gunnar Lindahl
  • Milan Tomana
  • Bruce A Julian
  • Robert J Wyatt
  • Jiri Mestecky
  • Jan Novak
Organisations
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Microbiology in the medical area
Original languageEnglish
Pages (from-to)69-78
JournalJournal of Molecular Biology
Volume369
Issue number1
Publication statusPublished - 2007
Publication categoryResearch
Peer-reviewedYes