title: Effects of N-glycosylation and inositol on the ER stress response in yeast Saccharomyces cerevisiae.
abstract: IRE1 and HAC1 are essential for the unfolded protein response in the endoplasmic reticulum (ER). IRE1- and HAC1-disruptants require high concentrations of inositol for its normal growth. The ALG6, ALG8, and ALG10 genes encode the glucosyltransferases necessary for the completion of the synthesis of the lipid-linked oligosaccharide used for the asparagine-linked glycosylation of proteins in that order. Here we show that, given a combination of the hac1 defect with a disruption of ALG6, ALG8, and ALG10, no strains grow on inositol-free medium. However, the growth defect of the hac1-alg10 double disrupted was partially, but significantly, suppressed by the addition of inositol to the medium. These results indicate that inositol, according to the numbers of glucose residues in the oligosaccharide, plays an important role in the stress response and quality control of glycoproteins in the ER.
authors.affiliation: Department of Bioscience and Bioinformatics, Faculty of Computer Science and Systems Engineering, Kyushu Institute of Technology, Iizuka, Fukuoka 820-8502, Japan.
authors.forename: Seiichi
authors.initials: S
authors.lastname: Uchimura
authors.forename: Minetaka
authors.initials: M
authors.lastname: Sugiyama
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Nikawa
mesh_terms: D002455:Cell Division / Q000187:drug effects / Q000235:genetics; D003470:Culture Media / Q000494:pharmacology; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects; D005838:Genotype; D005964:Glucosyltransferases / Q000235:genetics / Q000378:metabolism; D006031:Glycosylation; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D007294:Inositol / Q000494:pharmacology*; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism; D009004:Monosaccharide Transport Proteins; D009154:Mutation; D010641:Phenotype; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D014415:Tunicamycin / Q000494:pharmacology
chemical_list: D003470:Culture Media; D005656:Fungal Proteins; D018840:HSP70 Heat-Shock Proteins; C069143:ITR1 protein, S cerevisiae; C060153:KAR2 protein, yeast; D026901:Membrane Transport Proteins; D009004:Monosaccharide Transport Proteins; D029701:Saccharomyces cerevisiae Proteins; D014415:Tunicamycin; D007294:Inositol; C087974:Alg8 protein, S cerevisiae; C113849:DIE2 protein, S cerevisiae; D005964:Glucosyltransferases