title: Mapping the O-Mannose Glycoproteome in Saccharomyces cerevisiae.
abstract: O-Mannosylation is a vital protein modification conserved from fungi to humans. Yeast is a perfect model to study this post-translational modification, because in contrast to mammalsO-mannosylation is the only type ofO-glycosylation. In an essential step toward the full understanding of proteinO-mannosylation we mapped theO-mannose glycoproteome in baker's yeast. Taking advantage of anO-glycan elongation deficient yeast strain to simplify sample complexity, we identified over 500O-glycoproteins from all subcellular compartments for which over 2300O-mannosylation sites were mapped by electron-transfer dissociation (ETD)-based MS/MS. In this study, we focus on the 293O-glycoproteins (over 1900 glycosylation sites identified by ETD-MS/MS) that enter the secretory pathway and are targets of ER-localized proteinO-mannosyltransferases. We find thatO-mannosylation is not only a prominent modification of cell wall and plasma membrane proteins, but also of a large number of proteins from the secretory pathway with crucial functions in protein glycosylation, folding, quality control, and trafficking. The analysis of glycosylation sites revealed thatO-mannosylation is favored in unstructured regions and β-strands. Furthermore,O-mannosylation is impeded in the proximity ofN-glycosylation sites suggesting the interplay of these types of post-translational modifications. The detailed knowledge of the target proteins and theirO-mannosylation sites opens for discovery of new roles of this essential modification in eukaryotes, and for a first glance on the evolution of different types ofO-glycosylation from yeast to mammals.
authors.affiliation: From the ‡Centre for Organismal Studies (COS), Department of Cell Chemistry, Heidelberg University, Im Neuenheimer Feld 360, D-69120 Heidelberg, Germany;
authors.forename: Patrick
authors.initials: P
authors.lastname: Neubert
authors.affiliation: §Copenhagen Center for Glycomics, Departments of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark;
authors.forename: Adnan
authors.initials: A
authors.lastname: Halim
authors.affiliation: From the ‡Centre for Organismal Studies (COS), Department of Cell Chemistry, Heidelberg University, Im Neuenheimer Feld 360, D-69120 Heidelberg, Germany;
authors.forename: Martin
authors.initials: M
authors.lastname: Zauser
authors.affiliation: ¶Institute of Microbiology, Department of Biology, Swiss Federal Institute of Technology, ETH Zürich, CH-8093 Zürich, Switzerland.
authors.forename: Andreas
authors.initials: A
authors.lastname: Essig
authors.affiliation: §Copenhagen Center for Glycomics, Departments of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark;
authors.forename: Hiren J
authors.initials: HJ
authors.lastname: Joshi
authors.affiliation: From the ‡Centre for Organismal Studies (COS), Department of Cell Chemistry, Heidelberg University, Im Neuenheimer Feld 360, D-69120 Heidelberg, Germany;
authors.forename: Ewa
authors.initials: E
authors.lastname: Zatorska
authors.affiliation: §Copenhagen Center for Glycomics, Departments of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark;
authors.forename: Ida Signe Bohse
authors.initials: IS
authors.lastname: Larsen
authors.affiliation: From the ‡Centre for Organismal Studies (COS), Department of Cell Chemistry, Heidelberg University, Im Neuenheimer Feld 360, D-69120 Heidelberg, Germany;
authors.forename: Martin
authors.initials: M
authors.lastname: Loibl
authors.affiliation: From the ‡Centre for Organismal Studies (COS), Department of Cell Chemistry, Heidelberg University, Im Neuenheimer Feld 360, D-69120 Heidelberg, Germany;
authors.forename: Joan
authors.initials: J
authors.lastname: Castells-Ballester
authors.affiliation: ¶Institute of Microbiology, Department of Biology, Swiss Federal Institute of Technology, ETH Zürich, CH-8093 Zürich, Switzerland.
authors.forename: Markus
authors.initials: M
authors.lastname: Aebi
authors.affiliation: §Copenhagen Center for Glycomics, Departments of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark;
authors.forename: Henrik
authors.initials: H
authors.lastname: Clausen
authors.affiliation: From the ‡Centre for Organismal Studies (COS), Department of Cell Chemistry, Heidelberg University, Im Neuenheimer Feld 360, D-69120 Heidelberg, Germany; sabine.strahl@cos.uni-heidelberg.de.
authors.forename: Sabine
authors.initials: S
authors.lastname: Strahl
mesh_terms: D001665:Binding Sites; D004721:Endoplasmic Reticulum / Q000378:metabolism; D006023:Glycoproteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D006031:Glycosylation; D008358:Mannose / Q000378:metabolism*; D008958:Models, Molecular; D000072417:Protein Domains; D017433:Protein Structure, Secondary; D040901:Proteomics / Q000379:methods*; D012441:Saccharomyces cerevisiae / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D006023:Glycoproteins; D029701:Saccharomyces cerevisiae Proteins; D008358:Mannose