title: Nucleocytoplasmic human O-GlcNAc transferase is sufficient for O-GlcNAcylation of mitochondrial proteins.
abstract: O-linked N-acetylglucosamine modification (O-GlcNAcylation) is a nutrient-dependent protein post-translational modification (PTM), dynamically and reversibly driven by two enzymes: O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA) that catalyse the addition and the removal of the O-GlcNAc moieties to/from serine and threonine residues of target proteins respectively. Increasing evidence suggests involvement of O-GlcNAcylation in many biological processes, including transcription, signalling, neuronal development and mitochondrial function. The presence of a mitochondrial O-GlcNAc proteome and a mitochondrial OGT (mOGT) isoform has been reported. We explored the presence of mOGT in human cell lines and mouse tissues. Surprisingly, analysis of genomic sequences indicates that this isoform cannot be expressed in most of the species analysed, except some primates. In addition, we were not able to detect endogenous mOGT in a range of human cell lines. Knockdown experiments and Western blot analysis of all the predicted OGT isoforms suggested the expression of only a single OGT isoform. In agreement with this, we demonstrate that overexpression of the nucleocytoplasmic OGT (ncOGT) isoform leads to increased O-GlcNAcylation of mitochondrial proteins, suggesting that ncOGT is necessary and sufficient for the generation of the O-GlcNAc mitochondrial proteome.
authors.affiliation: School of Life Sciences, University of Dundee, Dundee DD1 4HN, U.K.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Trapannone
authors.affiliation: School of Life Sciences, University of Dundee, Dundee DD1 4HN, U.K.
authors.forename: Daniel
authors.initials: D
authors.lastname: Mariappa
authors.affiliation: School of Life Sciences, University of Dundee, Dundee DD1 4HN, U.K.
authors.forename: Andrew T
authors.initials: AT
authors.lastname: Ferenbach
authors.affiliation: School of Life Sciences, University of Dundee, Dundee DD1 4HN, U.K. Division of Molecular Microbiology, College of Life Sciences, University of Dundee, Dundee DD1 4HN, U.K. d.m.f.vanaalten@dundee.ac.uk.
authors.forename: Daan M F
authors.initials: DM
authors.lastname: van Aalten
mesh_terms: D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D002460:Cell Line; D002467:Cell Nucleus / Q000201:enzymology*; D003593:Cytoplasm / Q000201:enzymology*; D004591:Electrophoresis, Polyacrylamide Gel; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D047468:Immunoprecipitation; D051379:Mice; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D017351:N-Acetylglucosaminyltransferases / Q000235:genetics / Q000378:metabolism*; D016366:Open Reading Frames / Q000235:genetics; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D001619:beta-N-Acetylhexosaminidases / Q000235:genetics / Q000378:metabolism
chemical_list: D024101:Mitochondrial Proteins; D020033:Protein Isoforms; D017351:N-Acetylglucosaminyltransferases; C449880:O-GlcNAc transferase; C110628:hexosaminidase C; D001619:beta-N-Acetylhexosaminidases
keywords: O-GlcNAc transferase (OGT); O-linked N-acetylglucosamine (O-GlcNAc); alternative splicing; glycobiology; mitochondria; post-translational modification (PTM)