title: The hydroxylation activity of Jmjd6 is required for its homo-oligomerization.
abstract: Jumonji C-terminal (JmjC) domain-containing proteins are protein hydroxylases and histone demethylases that control gene expression. Jumonji domain-containing protein 6 (Jmjd6) is indispensable for embryonic development and has both histone arginine demethylase and lysyl-hydroxylase activities. The protein undergoes post-translational homo-oligomerization, but the underlying mechanism remains unknown. In this study, we examined the enzymatic activity of Jmjd6 and uncovered the mechanism underlying its homo-oligomerization. An in vitro enzymatic assay monitored by matrix-assisted laser desorption-ionization time-of-flight (MALDI-TOF) mass spectrometry indicates that Jmjd6 is unable to remove the methyl group from histone arginine residues but can hydroxylate the histone H4 tail at lysine residues in a 2-oxoglutarate (2-OG)- and Fe (II)-dependent manner. A mutational analysis reveals that the homo-oligomerization of Jmjd6 requires its enzymatic activity and the N- and C-termini. Using an in vitro enzymatic assay, we further demonstrate that Jmjd6 can hydroxylate its N-terminus but not its C-terminus. In summary, we did not detect arginine demethylase activity for Jmjd6, but we did confirm that it could catalyze the lysyl-hydroxylation of histone peptides. In addition, we demonstrated that the homo-oligomerization of Jmjd6 requires its own enzymatic activity and the N- and C-termini. We propose that Jmjd6 forms intermolecular covalent bonds between its N- and C-termini via autohydroxylation.
authors.affiliation: State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Han
authors.forename: Jiajia
authors.initials: J
authors.lastname: Li
authors.forename: Yiqin
authors.initials: Y
authors.lastname: Wang
authors.forename: Xia
authors.initials: X
authors.lastname: Li
authors.forename: Hailei
authors.initials: H
authors.lastname: Mao
authors.forename: Yifan
authors.initials: Y
authors.lastname: Liu
authors.forename: Charlie Degui
authors.initials: CD
authors.lastname: Chen
mesh_terms: D000595:Amino Acid Sequence; D057809:HEK293 Cells; D006657:Histones / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D006801:Humans; D006900:Hydroxylation; D066298:In Vitro Techniques; D056484:Jumonji Domain-Containing Histone Demethylases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D008240:Procollagen-Lysine, 2-Oxoglutarate 5-Dioxygenase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D055503:Protein Multimerization; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013379:Substrate Specificity
chemical_list: D006657:Histones; D011994:Recombinant Proteins; C498707:JMJD6 protein, human; D056484:Jumonji Domain-Containing Histone Demethylases; D008240:Procollagen-Lysine, 2-Oxoglutarate 5-Dioxygenase