RRC ID 34856
Author Harada Y, Buser R, Ngwa EM, Hirayama H, Aebi M, Suzuki T.
Title Eukaryotic oligosaccharyltransferase generates free oligosaccharides during N-glycosylation.
Journal J Biol Chem
Abstract Asparagine (N)-linked glycosylation regulates numerous cellular activities, such as glycoprotein quality control, intracellular trafficking, and cell-cell communications. In eukaryotes, the glycosylation reaction is catalyzed by oligosaccharyltransferase (OST), a multimembrane protein complex that is localized in the endoplasmic reticulum (ER). During N-glycosylation in the ER, the protein-unbound form of oligosaccharides (free oligosaccharides; fOSs), which is structurally related to N-glycan, is released into the ER lumen. However, the enzyme responsible for this process remains unidentified. Here, we demonstrate that eukaryotic OST generates fOSs. Biochemical and genetic analyses using mutant strains of Saccharomyces cerevisiae revealed that the generation of fOSs is tightly correlated with the N-glycosylation activity of OST. Furthermore, we present evidence that the purified OST complex can generate fOSs by hydrolyzing dolichol-linked oligosaccharide, the glycan donor substrate for N-glycosylation. The heterologous expression of a single subunit of OST from the protozoan Leishmania major in S. cerevisiae demonstrated that this enzyme functions both in N-glycosylation and generation of fOSs. This study provides insight into the mechanism of PNGase-independent formation of fOSs.
Volume 288(45)
Pages 32673-32684
Published 2013-11-8
DOI 10.1074/jbc.M113.486985
PII S0021-9258(20)48600-4
PMID 24062310
PMC PMC3820902
MeSH Glycosylation Hexosyltransferases / genetics Hexosyltransferases / metabolism* Leishmania major / enzymology* Leishmania major / genetics Membrane Proteins / genetics Membrane Proteins / metabolism* Oligosaccharides / genetics Oligosaccharides / metabolism* Polyisoprenyl Phosphate Oligosaccharides / metabolism Protozoan Proteins / genetics Protozoan Proteins / metabolism* Saccharomyces cerevisiae / enzymology* Saccharomyces cerevisiae / genetics Saccharomyces cerevisiae Proteins / genetics Saccharomyces cerevisiae Proteins / metabolism*
IF 4.238
Times Cited 30
DNA material YEp352-OST3 (RDB13158) YEp352-OST6 (RDB13159) pPRS425-GPD-ScSTT3 (RDB13160).