| Literature DB >> 17418236 |
Milan Raska1, 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.
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.Entities:
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Year: 2007 PMID： 17418236 PMCID： PMC1995659 DOI： 10.1016/j.jmb.2007.03.002
Source DB: PubMed Journal: J Mol Biol ISSN： 0022-2836 Impact factor: 5.469