Identification and characterization of CMP-NeuAc:GalNAc-IgA1 alpha2,6-sialyltransferase in IgA1-producing cells.
J Mol Biol
; 369(1): 69-78, 2007 May 25.
Article
em En
| MEDLINE
| ID: mdl-17418236
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-NeuAcGalNAc-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-NeuAcGalNAc-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.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Sialiltransferases
/
Imunoglobulina A
Tipo de estudo:
Diagnostic_studies
Limite:
Humans
Idioma:
En
Revista:
J Mol Biol
Ano de publicação:
2007
Tipo de documento:
Article