title: Regulation of Oct1/Pou2f1 transcription activity by O-GlcNAcylation.
abstract: The Oct1 transcription factor is a potent regulator of stress responses, metabolism, and tumorigenicity. Although Oct1 is regulated by phosphorylation and ubiquitination, the presence and importance of other modifications is unknown. Here we show that Oct1 is modified by O-linked β-N-acetylglucosamine (O-GlcNAc) moieties. We map two sites of O-GlcNAcylation at positions T255 and S728 within human Oct1. Under anchorage-independent overgrowth conditions, Oct1 associates 3-fold more strongly with the Gadd45a promoter and mediates transcriptional repression. Increased binding correlates with quantitative reductions in Oct1 nuclear periphery-associated puncta, and a reduced association with lamin B1. The O-GlcNAc modification sites are important for both Gadd45a repression and anchorage-independent survival. In contrast to chronic overgrowth conditions, following acute nutrient starvation Oct1 mediates Gadd45a activation. The O-GlcNAc sites are also important for Gadd45a activation under these conditions. We also, for the first time, identify specific Oct1 ubiquitination sites. The findings suggest that Oct1 integrates metabolic and stress signals via O-GlcNAc modification to regulate target gene activity.
authors.affiliation: Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT 84112, USA.
authors.forename: Jinsuk
authors.initials: J
authors.lastname: Kang
authors.forename: Zuolian
authors.initials: Z
authors.lastname: Shen
authors.forename: Jae-Min
authors.initials: JM
authors.lastname: Lim
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Handa
authors.forename: Lance
authors.initials: L
authors.lastname: Wells
authors.forename: Dean
authors.initials: D
authors.lastname: Tantin
mesh_terms: D016475:3T3 Cells; D000117:Acetylglucosamine / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites / Q000235:genetics; D018797:Cell Cycle Proteins / Q000235:genetics; D004622:Embryo, Mammalian / Q000166:cytology; D005347:Fibroblasts / Q000378:metabolism; D005786:Gene Expression Regulation; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D015151:Immunoblotting; D051379:Mice; D018345:Mice, Knockout; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050819:Transcription Factor Brn-3A / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation; D000097642:GADD45 Proteins
chemical_list: D000117:Acetylglucosamine; D018797:Cell Cycle Proteins; D049452:Green Fluorescent Proteins; D009687:Nuclear Proteins; D050819:Transcription Factor Brn-3A; C439070:GADD45A protein, human; D000097642:GADD45 Proteins; C494188:POU4F1 protein, human
keywords: Gadd45a; Lamin B