title: Global and Site-Specific Analysis Revealing Unexpected and Extensive Protein S-GlcNAcylation in Human Cells.
abstract: Protein glycosylation is highly diverse and essential for mammalian cell survival. Heterogeneous glycans may be bound to different amino acid residues, forming multiple types of protein glycosylation. In this work, unexpected protein S-GlcNAcylation on cysteine residues was observed to extensively exist in human cells through global and site-specific analysis of protein GlcNAcylation by mass spectrometry. Three independent experiments produced similar results of many cysteine residues bound to N-acetylglucosamine (GlcNAc). Among well-localized S-GlcNAcylation sites, several motifs with an acidic amino acid around the sites were identified, which strongly suggests that a particular type of enzyme is responsible for this modification. Clustering results show that glycoproteins modified with S-GlcNAc are mainly involved in cell-cell adhesion and gene expression. For the first time, we found that proteins were extensively bound to GlcNAc through the side chains of cysteine residues in human cells, and the current discovery further advances our understanding of protein glycosylation.
authors.affiliation: School of Chemistry and Biochemistry and the Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology , Atlanta, Georgia 30332, United States.
authors.forename: Haopeng
authors.initials: H
authors.lastname: Xiao
authors.affiliation: School of Chemistry and Biochemistry and the Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology , Atlanta, Georgia 30332, United States.
authors.forename: Ronghu
authors.identifier: 0000-0001-9493-9462
authors.initials: R
authors.lastname: Wu
mesh_terms: D000117:Acetylglucosamine / Q000032:analysis* / Q000378:metabolism; D003545:Cysteine / Q000737:chemistry / Q000378:metabolism; D006023:Glycoproteins / Q000737:chemistry / Q000378:metabolism*; D006031:Glycosylation; D006801:Humans; D061986:MCF-7 Cells; D013058:Mass Spectrometry; D008968:Molecular Conformation; D011499:Protein Processing, Post-Translational; D040901:Proteomics; D011786:Quality Control; D014407:Tumor Cells, Cultured
chemical_list: D006023:Glycoproteins; D003545:Cysteine; D000117:Acetylglucosamine