title: Advances in mass spectrometry driven O-glycoproteomics.
abstract: BACKGROUND
  Global analyses of proteins and their modifications by mass spectrometry are essential tools in cell biology and biomedical research. Analyses of glycoproteins represent particular challenges and we are only at the beginnings of the glycoproteomic era. Some of the challenges have been overcome with N-glycoproteins and proteome-wide analysis of N-glycosylation sites is accomplishable today but only by sacrificing information of structures at individual glycosites. More recently advances in analysis of O-glycoproteins have been made and proteome-wide analysis of O-glycosylation sites is becoming available as well.
  
  
  METHODS
  Here we discuss the challenges of analysis of O-glycans and new O-glycoproteomics strategies focusing on O-GalNAc and O-Man glycoproteomes.
  
  
  CONCLUSIONS
  A variety of strategies are now available for proteome-wide analysis of O-glycosylation sites enabling functional studies. However, further developments are still needed for complete analysis of glycan structures at individual sites for both N- and O-glycoproteomics strategies.
  
  
  CONCLUSIONS
  The advances in O-glycoproteomics have led to identification of new biological functions of O-glycosylation and a new understanding of the importance of where O-glycans are positioned on proteins.
authors.affiliation: Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark.
authors.forename: Steven B
authors.initials: SB
authors.lastname: Levery
authors.affiliation: Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark.
authors.forename: Catharina
authors.initials: C
authors.lastname: Steentoft
authors.affiliation: Copenhagen Center for Glycomics, Department 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: Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark.
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Narimatsu
authors.affiliation: Copenhagen Center for Glycomics, Department 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: Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark. Electronic address: seva@sund.ku.dk.
authors.forename: Sergey Y
authors.initials: SY
authors.lastname: Vakhrushev
mesh_terms: D002460:Cell Line; D045744:Cell Line, Tumor; D006023:Glycoproteins / Q000378:metabolism*; D006031:Glycosylation; D006801:Humans; D013058:Mass Spectrometry / Q000379:methods* / Q000639:trends; D011134:Polysaccharides / Q000378:metabolism; D020543:Proteome / Q000378:metabolism*; D040901:Proteomics / Q000379:methods* / Q000639:trends
chemical_list: D006023:Glycoproteins; D011134:Polysaccharides; D020543:Proteome
keywords: ETD; Glycopeptide; Lectin; Orbitrap; SimpleCell; Site-specific