title: Systematic identification of methyllysine-driven interactions for histone and nonhistone targets.
abstract: An important issue in epigenetic research is to understand how the numerous methylation marks associated with histone and certain nonhistone proteins are recognized and interpreted by the hundreds of chromatin-binding modules (CBMs) in a cell to control chromatin state, gene expression, and other cellular functions. We have assembled a peptide chip that represents known and putative lysine methylation marks on histones and p53 and probed the chip for binding to a group of CBMs to obtain a comprehensive interaction network mediated by lysine methylation. Interactions revealed by the peptide array screening were validated by in-solution binding assays. This study not only recapitulated known interactions but also uncovered new ones. A novel heterochromatin protein 1 beta (HP1β) chromodomain-binding site on histone H3, H3K23me, was discovered from the peptide array screen and subsequently verified by mass spectrometry. Data from peptide pull-down and colocalization in cells suggest that, besides the H3K9me mark, H3K23me may play a role in facilitating the recruitment of HP1β to the heterochromatin. Extending the peptide array and mass spectrometric approach presented here to more histone marks and CBMs would eventually afford a comprehensive specificity and interaction map to aid epigenetic studies.
authors.affiliation: Department of Biochemistry, The University of Western Ontario, London, Ontario, N6A 5C1, Canada.
authors.forename: Huadong
authors.initials: H
authors.lastname: Liu
authors.forename: Marek
authors.initials: M
authors.lastname: Galka
authors.forename: Aimee
authors.initials: A
authors.lastname: Iberg
authors.forename: Zezhou
authors.initials: Z
authors.lastname: Wang
authors.forename: Lei
authors.initials: L
authors.lastname: Li
authors.forename: Courtney
authors.initials: C
authors.lastname: Voss
authors.forename: Xinfeng
authors.initials: X
authors.lastname: Jiang
authors.forename: Gilles
authors.initials: G
authors.lastname: Lajoie
authors.forename: Zhiping
authors.initials: Z
authors.lastname: Huang
authors.forename: Mark T
authors.initials: MT
authors.lastname: Bedford
authors.forename: Shawn S C
authors.initials: SS
authors.lastname: Li
mesh_terms: D000090266:Chromobox Protein Homolog 5; D057890:Epigenomics; D006657:Histones / Q000032:analysis* / Q000378:metabolism; D006801:Humans; D008239:Lysine / Q000378:metabolism*; D008745:Methylation; D040081:Protein Array Analysis; D011485:Protein Binding; D016159:Tumor Suppressor Protein p53 / Q000032:analysis* / Q000378:metabolism
chemical_list: C000715593:CBX1 protein, human; D006657:Histones; D016159:Tumor Suppressor Protein p53; D000090266:Chromobox Protein Homolog 5; D008239:Lysine