title: Chromosomal protein HMGN1 modulates the phosphorylation of serine 1 in histone H2A.
abstract: Here we demonstrate that HMGN1, a nuclear protein that binds specifically to nucleosomes, modulates the level of histone H2A phosphorylation. In Hmgn1-/- cells, loss of HMGN1 elevates the steady-state levels of H2AS1ph throughout the cell cycle. In vitro, HMGN1 reduces the rate of Rsk2- and Msk1-mediated phosphorylation of nucleosomal, but not free, histone H2A. HMGN1 inhibits H2A phosphorylation by binding to nucleosomes since an HMGN mutant, which cannot bind to chromatin, does not inhibit the Rsk2- mediated H2A phosphorylation. HMGN2 also inhibits H2A phosphorylation, suggesting that the inhibition of H2A phosphorylation is not specific to only one member of this protein family. Thus, the present data add modifications of histone H2A to the list of histone modifications affected by HMGN proteins. It supports the suggestion that structural chromatin binding proteins can modify the whole profile of post-translational modifications of core histones.
authors.affiliation: Protein Section, Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA. yupo@helix.nih.gov
authors.forename: Yuri V
authors.initials: YV
authors.lastname: Postnikov
authors.forename: Galina I
authors.initials: GI
authors.lastname: Belova
authors.forename: Jae-Hwan
authors.initials: JH
authors.lastname: Lim
authors.forename: Michael
authors.initials: M
authors.lastname: Bustin
mesh_terms: D000818:Animals; D002453:Cell Cycle / Q000235:genetics; D002460:Cell Line; D024241:HMGN1 Protein / Q000235:genetics / Q000378:metabolism*; D006657:Histones / Q000378:metabolism*; D051379:Mice; D009154:Mutation; D009707:Nucleosomes / Q000378:metabolism; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational / Q000235:genetics; D038744:Ribosomal Protein S6 Kinases, 90-kDa / Q000378:metabolism; D012694:Serine / Q000378:metabolism
chemical_list: D024241:HMGN1 Protein; D006657:Histones; D009707:Nucleosomes; D012694:Serine; D038744:Ribosomal Protein S6 Kinases, 90-kDa; C116919:mitogen and stress-activated protein kinase 1; C069330:ribosomal protein S6 kinase, 90kDa, polypeptide 3