title: Mitotic phosphorylation of histone H3 threonine 80.
abstract: The onset and regulation of mitosis is dependent on phosphorylation of a wide array of proteins. Among the proteins that are phosphorylated during mitosis is histone H3, which is heavily phosphorylated on its N-terminal tail. In addition, large-scale mass spectrometry screens have revealed that histone H3 phosphorylation can occur at multiple sites within its globular domain, yet detailed analyses of the functions of these phosphorylations are lacking. Here, we explore one such histone H3 phosphorylation site, threonine 80 (H3T80), which is located on the nucleosome surface. Phosphorylated H3T80 (H3T80ph) is enriched in metazoan cells undergoing mitosis. Unlike H3S10 and H3S28, H3T80 is not phosphorylated by the Aurora B kinase. Further, mutations of T80 to either glutamic acid, a phosphomimetic, or to alanine, an unmodifiable residue, result in an increase in cells in prophase and an increase in anaphase/telophase bridges, respectively. SILAC-coupled mass spectrometry shows that phosphorylated H3T80 (H3T80ph) preferentially interacts with histones H2A and H4 relative to non-phosphorylated H3T80, and this result is supported by increased binding of H3T80ph to histone octamers in vitro. These findings support a model where H3T80ph, protruding from the nucleosome surface, promotes interactions between adjacent nucleosomes to promote chromatin compaction during mitosis in metazoan cells.
authors.affiliation: Department of Biochemistry and Molecular Biology; University of Texas; MD Anderson Cancer Center; Houston, TX USA; Department of Molecular and Cellular Biology; Baylor College of Medicine; Houston, Texas USA.
authors.forename: Sharra L
authors.initials: SL
authors.lastname: Hammond
authors.affiliation: Department of Biochemistry and Molecular Biology; University of Arkansas for Medical Sciences; Little Rock, AR USA.
authors.forename: Stephanie D
authors.initials: SD
authors.lastname: Byrum
authors.affiliation: Department of Biochemistry and Molecular Biology; University of Texas; MD Anderson Cancer Center; Houston, TX USA.
authors.forename: Sarita
authors.initials: S
authors.lastname: Namjoshi
authors.affiliation: Department of Biochemistry and Molecular Biology; University of Texas; MD Anderson Cancer Center; Houston, TX USA.
authors.forename: Hillary K
authors.initials: HK
authors.lastname: Graves
authors.affiliation: Department of Biochemistry and Molecular Biology; University of Texas; MD Anderson Cancer Center; Houston, TX USA.
authors.forename: Briana K
authors.initials: BK
authors.lastname: Dennehey
authors.affiliation: Department of Biochemistry and Molecular Biology; University of Arkansas for Medical Sciences; Little Rock, AR USA.
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Tackett
authors.affiliation: Department of Biochemistry and Molecular Biology; University of Texas; MD Anderson Cancer Center; Houston, TX USA; Department of Molecular and Cellular Biology; Baylor College of Medicine; Houston, Texas USA.
authors.forename: Jessica K
authors.initials: JK
authors.lastname: Tyler
mesh_terms: D000595:Amino Acid Sequence; D000906:Antibodies / Q000276:immunology; D000918:Antibody Specificity; D045744:Cell Line, Tumor; D002843:Chromatin / Q000378:metabolism; D006657:Histones / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D008938:Mitosis; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D009707:Nucleosomes / Q000378:metabolism; D010766:Phosphorylation; D011485:Protein Binding; D013912:Threonine / Q000378:metabolism*
chemical_list: D000906:Antibodies; D002843:Chromatin; D006657:Histones; D009707:Nucleosomes; D013912:Threonine
keywords: chromatin condensation; histone phosphorylation; mitosis