title: β-N-Acetylglucosamine (O-GlcNAc) is a novel regulator of mitosis-specific phosphorylations on histone H3.
abstract: O-Linked β-N-acetylglucosamine, or O-GlcNAc, is a dynamic post-translational modification that cycles on and off serine and threonine residues of nucleocytoplasmic proteins. The O-GlcNAc modification shares a complex relationship with phosphorylation, as both modifications are capable of mutually inhibiting the occupation of each other on the same or nearby amino acid residue. In addition to diabetes, cancer, and neurodegenerative diseases, O-GlcNAc appears to play a significant role in cell growth and cell cycle progression, although the precise mechanisms are still not well understood. A recent study also found that all four core nucleosomal histones (H2A, H2B, H3, and H4) are modified with O-GlcNAc, although no specific sites on H3 were reported. Here, we describe that histone H3, a protein highly phosphorylated during mitosis, is modified with O-GlcNAc. Several biochemical assays were used to validate that H3 is modified with O-GlcNAc. Mass spectrometry analysis identified threonine 32 as a novel O-GlcNAc site. O-GlcNAc was detected at higher levels on H3 during interphase than mitosis, which inversely correlated with phosphorylation. Furthermore, increased O-GlcNAcylation was observed to reduce mitosis-specific phosphorylation at serine 10, serine 28, and threonine 32. Finally, inhibiting OGA, the enzyme responsible for removing O-GlcNAc, hindered the transition from G2 to M phase of the cell cycle, displaying a phenotype similar to preventing mitosis-specific phosphorylation on H3. Taken together, these data indicate that O-GlcNAcylation regulates mitosis-specific phosphorylations on H3, providing a mechanistic switch that orchestrates the G2-M transition of the cell cycle.
authors.affiliation: Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas 77030-3498, USA.
authors.forename: Jerry J
authors.initials: JJ
authors.lastname: Fong
authors.forename: Brenda L
authors.initials: BL
authors.lastname: Nguyen
authors.forename: Robert
authors.initials: R
authors.lastname: Bridger
authors.forename: Estela E
authors.initials: EE
authors.lastname: Medrano
authors.forename: Lance
authors.initials: L
authors.lastname: Wells
authors.forename: Shujuan
authors.initials: S
authors.lastname: Pan
authors.forename: Richard N
authors.initials: RN
authors.lastname: Sifers
mesh_terms: D000117:Acetylglucosamine / Q000378:metabolism / Q000502:physiology*; D000595:Amino Acid Sequence; D016195:G2 Phase; D006031:Glycosylation; D006367:HeLa Cells; D006657:Histones / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D047468:Immunoprecipitation; D008938:Mitosis; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D013912:Threonine / Q000378:metabolism
chemical_list: D006657:Histones; D010446:Peptide Fragments; D013912:Threonine; D000117:Acetylglucosamine