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dc.contributor.authorKaraoglu, Denise
dc.contributor.authorKelleher, Daniel J.
dc.contributor.authorGilmore, Reid
dc.date2022-08-11T08:10:05.000
dc.date.accessioned2022-08-23T16:54:57Z
dc.date.available2022-08-23T16:54:57Z
dc.date.issued1995-08-01
dc.date.submitted2008-10-31
dc.identifier.citationJ Cell Biol. 1995 Aug;130(3):567-77.
dc.identifier.issn0021-9525 (Print)
dc.identifier.pmid7622558
dc.identifier.urihttp://hdl.handle.net/20.500.14038/42615
dc.description.abstractWithin the lumen of the rough endoplasmic reticulum, oligosaccharyltransferase catalyzes the en bloc transfer of a high mannose oligosaccharide moiety from the lipid-linked oligosaccharide donor to asparagine acceptor sites in nascent polypeptides. The Saccharomyces cerevisiae oligosaccharyltransferase was purified as a heteroligomeric complex consisting of six subunits (alpha-zeta) having apparent molecular masses of 64 kD (Ost1p), 45 kD (Wbp1p), 34 kD, 30 kD (Swp1p), 16 kD, and 9 kD. Here we report a structural and functional characterization of Ost3p which corresponds to the 34-kD gamma-subunit of the oligosaccharyltransferase. Unlike Ost1p, Wbp1p, and Swp1p, expression of Ost3p is not essential for viability of yeast. Instead, ost3 null mutant yeast grow at wild-type rates on solid or in liquid media irrespective of culture temperature. Nonetheless, detergent extracts prepared from ost3 null mutant membranes are twofold less active than extracts prepared from wild-type membranes in an in vitro oligosaccharyltransferase assay. Furthermore, loss of Ost3p is accompanied by significant underglycosylation of soluble and membrane-bound glycoproteins in vivo. Compared to the previously characterized ost1-1 mutant in the oligosaccharyltransferase, and the alg5 mutant in the oligosaccharide assembly pathway, ost3 null mutant yeast appear to be selectively impaired in the glycosylation of several membrane glycoproteins. The latter observation suggests that Ost3p may enhance oligosaccharide transfer in vivo to a subset of acceptor substrates.
dc.language.isoen_US
dc.relation<a href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&list_uids=7622558&dopt=Abstract">Link to Article in PubMed</a>
dc.subjectAmino Acid Sequence
dc.subjectBase Sequence
dc.subjectCarbohydrate Sequence
dc.subjectCrosses, Genetic
dc.subjectEndoplasmic Reticulum
dc.subjectGenes, Fungal
dc.subjectGenomic Library
dc.subjectGlycosylation
dc.subject*Hexosyltransferases
dc.subjectMembrane Glycoproteins
dc.subject*Membrane Proteins
dc.subjectMolecular Sequence Data
dc.subjectMutagenesis
dc.subjectOligosaccharides
dc.subjectPrecipitin Tests
dc.subjectProtein Conformation
dc.subjectProtein Processing, Post-Translational
dc.subjectSaccharomyces cerevisiae
dc.subjectSequence Analysis
dc.subjectTransferases
dc.subjectBiochemistry
dc.subjectCell Biology
dc.subjectMolecular Biology
dc.titleFunctional characterization of Ost3p. Loss of the 34-kD subunit of the Saccharomyces cerevisiae oligosaccharyltransferase results in biased underglycosylation of acceptor substrates
dc.typeArticle
dc.source.journaltitleThe Journal of cell biology
dc.source.volume130
dc.source.issue3
dc.identifier.legacyfulltexthttps://escholarship.umassmed.edu/cgi/viewcontent.cgi?article=1946&amp;context=oapubs&amp;unstamped=1
dc.identifier.legacycoverpagehttps://escholarship.umassmed.edu/oapubs/947
dc.identifier.contextkey659128
refterms.dateFOA2022-08-23T16:54:58Z
html.description.abstract<p>Within the lumen of the rough endoplasmic reticulum, oligosaccharyltransferase catalyzes the en bloc transfer of a high mannose oligosaccharide moiety from the lipid-linked oligosaccharide donor to asparagine acceptor sites in nascent polypeptides. The Saccharomyces cerevisiae oligosaccharyltransferase was purified as a heteroligomeric complex consisting of six subunits (alpha-zeta) having apparent molecular masses of 64 kD (Ost1p), 45 kD (Wbp1p), 34 kD, 30 kD (Swp1p), 16 kD, and 9 kD. Here we report a structural and functional characterization of Ost3p which corresponds to the 34-kD gamma-subunit of the oligosaccharyltransferase. Unlike Ost1p, Wbp1p, and Swp1p, expression of Ost3p is not essential for viability of yeast. Instead, ost3 null mutant yeast grow at wild-type rates on solid or in liquid media irrespective of culture temperature. Nonetheless, detergent extracts prepared from ost3 null mutant membranes are twofold less active than extracts prepared from wild-type membranes in an in vitro oligosaccharyltransferase assay. Furthermore, loss of Ost3p is accompanied by significant underglycosylation of soluble and membrane-bound glycoproteins in vivo. Compared to the previously characterized ost1-1 mutant in the oligosaccharyltransferase, and the alg5 mutant in the oligosaccharide assembly pathway, ost3 null mutant yeast appear to be selectively impaired in the glycosylation of several membrane glycoproteins. The latter observation suggests that Ost3p may enhance oligosaccharide transfer in vivo to a subset of acceptor substrates.</p>
dc.identifier.submissionpathoapubs/947
dc.contributor.departmentDepartment of Biochemistry and Molecular Biology
dc.source.pages567-77


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