title: G9a-mediated lysine methylation alters the function of CCAAT/enhancer-binding protein-beta.
abstract: The functional capacity of the transcriptional regulatory CCAAT/enhancer-binding protein-beta (C/EBPbeta) is governed by protein interactions and post-translational protein modifications. In a proteome-wide interaction screen, the histone-lysine N-methyltransferase, H3 lysine 9-specific 3 (G9a), was found to directly interact with the C/EBPbeta transactivation domain (TAD). Binding between G9a and C/EBPbeta was confirmed by glutathione S-transferase pulldown and co-immunoprecipitation. Metabolic labeling showed that C/EBPbeta is post-translationally modified by methylation in vivo. A conserved lysine residue in the C/EBPbeta TAD served as a substrate for G9a-mediated methylation. G9a, but not a methyltransferase-defective G9a mutant, abrogated the transactivation potential of wild type C/EBPbeta. A C/EBPbeta TAD mutant that contained a lysine-to-alanine exchange was resistant to G9a-mediated inhibition. Moreover, the same mutation conferred super-activation of a chromatin-embedded, endogenous C/EBPbeta target gene. Our data identify C/EBPbeta as a direct substrate of G9a-mediated post-translational modification that alters the functional properties of C/EBPbeta during gene regulation.
authors.affiliation: Max Delbrück Center for Molecular Medicine, Humboldt University of Berlin, Berlin, Germany.
authors.forename: Ole
authors.initials: O
authors.lastname: Pless
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Kowenz-Leutz
authors.forename: Maria
authors.initials: M
authors.lastname: Knoblich
authors.forename: Jörn
authors.initials: J
authors.lastname: Lausen
authors.forename: Michael
authors.initials: M
authors.lastname: Beyermann
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Walsh
authors.forename: Achim
authors.initials: A
authors.lastname: Leutz
mesh_terms: D022782:CCAAT-Enhancer-Binding Protein-beta / Q000235:genetics / Q000378:metabolism*; D006367:HeLa Cells; D006649:Histocompatibility Antigens / Q000235:genetics / Q000378:metabolism*; D011495:Histone-Lysine N-Methyltransferase / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D009154:Mutation; D011499:Protein Processing, Post-Translational / Q000502:physiology*; D017434:Protein Structure, Tertiary / Q000502:physiology; D020543:Proteome / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation / Q000502:physiology*
chemical_list: D022782:CCAAT-Enhancer-Binding Protein-beta; D006649:Histocompatibility Antigens; D020543:Proteome; C445405:EHMT2 protein, human; D011495:Histone-Lysine N-Methyltransferase