title: A method for systematic mapping of protein lysine methylation identifies functions for HP1β in DNA damage response.
abstract: Lysine methylation occurs on both histone and nonhistone proteins. However, our knowledge on the prevalence and function of nonhistone protein methylation is poor. We describe an approach that combines peptide array, bioinformatics, and mass spectrometry to systematically identify lysine methylation sites and map methyllysine-driven protein-protein interactions. Using this approach, we identified a high-confidence and high-resolution interactome of the heterochromatin protein 1β (HP1β) and uncovered, simultaneously, numerous methyllysine sites on nonhistone proteins. We found that HP1β binds to DNA-dependent protein kinase catalytic subunit (DNA-PKcs) and regulates its localization to double-strand breaks (DSBs) during DNA damage response (DDR). Mutation of the methylation sites in DNA-PKcs or depletion of HP1β in cells caused defects in DDR. Furthermore, we showed that the methylation of DNA-PKcs and many other proteins in the HP1β interactome undergoes large changes in response to DNA damage, indicating that Lys methylation is a highly dynamic posttranslational modification.
authors.affiliation: Department of Biochemistry and the Siebens-Drake Medical Research Institute, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON N6A 5C1, Canada.
authors.forename: Huadong
authors.initials: H
authors.lastname: Liu
authors.forename: Marek
authors.initials: M
authors.lastname: Galka
authors.forename: Eiichiro
authors.initials: E
authors.lastname: Mori
authors.forename: Xuguang
authors.initials: X
authors.lastname: Liu
authors.forename: Yu-Fen
authors.initials: YF
authors.lastname: Lin
authors.forename: Ran
authors.initials: R
authors.lastname: Wei
authors.forename: Paula
authors.initials: P
authors.lastname: Pittock
authors.forename: Courtney
authors.initials: C
authors.lastname: Voss
authors.forename: Gurpreet
authors.initials: G
authors.lastname: Dhami
authors.forename: Xing
authors.initials: X
authors.lastname: Li
authors.forename: Masaaki
authors.initials: M
authors.lastname: Miyaji
authors.forename: Gilles
authors.initials: G
authors.lastname: Lajoie
authors.forename: Benjamin
authors.initials: B
authors.lastname: Chen
authors.forename: Shawn Shun-Cheng
authors.initials: SS
authors.lastname: Li
mesh_terms: D020134:Catalytic Domain; D000090266:Chromobox Protein Homolog 5; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism*; D053903:DNA Breaks, Double-Stranded; D004249:DNA Damage; D051747:DNA-Activated Protein Kinase / Q000378:metabolism; D057166:High-Throughput Screening Assays / Q000379:methods*; D006801:Humans; D008239:Lysine / Q000378:metabolism*; D008745:Methylation; D009154:Mutation; D011499:Protein Processing, Post-Translational; D011506:Proteins / Q000032:analysis* / Q000378:metabolism; D015203:Reproducibility of Results
chemical_list: C000715593:CBX1 protein, human; D002868:Chromosomal Proteins, Non-Histone; D011506:Proteins; D000090266:Chromobox Protein Homolog 5; D051747:DNA-Activated Protein Kinase; D008239:Lysine