1
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Okuda M, Tsunaka Y, Nishimura Y. Dynamic structures of intrinsically disordered proteins related to the general transcription factor TFIIH, nucleosomes, and histone chaperones. Biophys Rev 2022; 14:1449-1472. [PMID: 36659983 PMCID: PMC9842849 DOI: 10.1007/s12551-022-01014-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 11/06/2022] [Indexed: 11/19/2022] Open
Abstract
Advances in structural analysis by cryogenic electron microscopy (cryo-EM) and X-ray crystallography have revealed the tertiary structures of various chromatin-related proteins, including transcription factors, RNA polymerases, nucleosomes, and histone chaperones; however, the dynamic structures of intrinsically disordered regions (IDRs) in these proteins remain elusive. Recent studies using nuclear magnetic resonance (NMR), together with molecular dynamics (MD) simulations, are beginning to reveal dynamic structures of the general transcription factor TFIIH complexed with target proteins including the general transcription factor TFIIE, the tumor suppressor p53, the cell cycle protein DP1, the DNA repair factors XPC and UVSSA, and three RNA polymerases, in addition to the dynamics of histone tails in nucleosomes and histone chaperones. In complexes of TFIIH, the PH domain of the p62 subunit binds to an acidic string formed by the IDR in TFIIE, p53, XPC, UVSSA, DP1, and the RPB6 subunit of three RNA polymerases by a common interaction mode, namely extended string-like binding of the IDR on the positively charged surface of the PH domain. In the nucleosome, the dynamic conformations of the N-tails of histones H2A and H2B are correlated, while the dynamic conformations of the N-tails of H3 and H4 form a histone tail network dependent on their modifications and linker DNA. The acidic IDRs of the histone chaperones of FACT and NAP1 play important roles in regulating the accessibility to histone proteins in the nucleosome.
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Affiliation(s)
- Masahiko Okuda
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-Cho, Tsurumi-Ku, Yokohama, 230-0045 Japan
| | - Yasuo Tsunaka
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-Cho, Tsurumi-Ku, Yokohama, 230-0045 Japan
| | - Yoshifumi Nishimura
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-Cho, Tsurumi-Ku, Yokohama, 230-0045 Japan
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-4-4 Kagamiyama, Higashi-Hiroshima, 739-8528 Japan
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2
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Abascal-Palacios G, Jochem L, Pla-Prats C, Beuron F, Vannini A. Structural basis of Ty3 retrotransposon integration at RNA Polymerase III-transcribed genes. Nat Commun 2021; 12:6992. [PMID: 34848735 PMCID: PMC8632968 DOI: 10.1038/s41467-021-27338-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 11/15/2021] [Indexed: 12/29/2022] Open
Abstract
Retrotransposons are endogenous elements that have the ability to mobilise their DNA between different locations in the host genome. The Ty3 retrotransposon integrates with an exquisite specificity in a narrow window upstream of RNA Polymerase (Pol) III-transcribed genes, representing a paradigm for harmless targeted integration. Here we present the cryo-EM reconstruction at 4.0 Å of an active Ty3 strand transfer complex bound to TFIIIB transcription factor and a tRNA gene. The structure unravels the molecular mechanisms underlying Ty3 targeting specificity at Pol III-transcribed genes and sheds light into the architecture of retrotransposon machinery during integration. Ty3 intasome contacts a region of TBP, a subunit of TFIIIB, which is blocked by NC2 transcription regulator in RNA Pol II-transcribed genes. A newly-identified chromodomain on Ty3 integrase interacts with TFIIIB and the tRNA gene, defining with extreme precision the integration site position.
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Affiliation(s)
| | - Laura Jochem
- Division of Structural Biology, The Institute of Cancer Research, London, SW7 3RP, UK
| | - Carlos Pla-Prats
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Fabienne Beuron
- Division of Structural Biology, The Institute of Cancer Research, London, SW7 3RP, UK
| | - Alessandro Vannini
- Division of Structural Biology, The Institute of Cancer Research, London, SW7 3RP, UK.
- Human Technopole, 20157, Milan, Italy.
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3
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Shi XX, Wang ZZ, Wang YL, Huang GY, Yang JF, Wang F, Hao GF, Yang GF. PTMdyna: exploring the influence of post-translation modifications on protein conformational dynamics. Brief Bioinform 2021; 23:6394992. [PMID: 34643234 DOI: 10.1093/bib/bbab424] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Revised: 09/02/2021] [Accepted: 09/14/2021] [Indexed: 11/14/2022] Open
Abstract
Protein post-translational modifications (PTM) play vital roles in cellular regulation, modulating functions by driving changes in protein structure and dynamics. Exploring comprehensively the influence of PTM on conformational dynamics can facilitate the understanding of the related biological function and molecular mechanism. Currently, a series of excellent computation tools have been designed to analyze the time-dependent structural properties of proteins. However, the protocol aimed to explore conformational dynamics of post-translational modified protein is still a blank. To fill this gap, we present PTMdyna to visually predict the conformational dynamics differences between unmodified and modified proteins, thus indicating the influence of specific PTM. PTMdyna exhibits an AUC of 0.884 tested on 220 protein-protein complex structures. The case of heterochromatin protein 1α complexed with lysine 9-methylated histone H3, which is critical for genomic stability and cell differentiation, was used to demonstrate its applicability. PTMdyna provides a reliable platform to predict the influence of PTM on protein dynamics, making it easier to interpret PTM functionality at the structure level. The web server is freely available at http://ccbportal.com/PTMdyna.
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Affiliation(s)
- Xing-Xing Shi
- Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, Hubei, P. R. China.,International Joint Research Center for Intelligent Biosensor Technology and Health, Central China Normal University, Wuhan, Hubei, P. R. China
| | - Zhi-Zheng Wang
- Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, Hubei, P. R. China.,International Joint Research Center for Intelligent Biosensor Technology and Health, Central China Normal University, Wuhan, Hubei, P. R. China
| | - Yu-Liang Wang
- Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, Hubei, P. R. China.,International Joint Research Center for Intelligent Biosensor Technology and Health, Central China Normal University, Wuhan, Hubei, P. R. China
| | - Guang-Yi Huang
- Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, Hubei, P. R. China.,International Joint Research Center for Intelligent Biosensor Technology and Health, Central China Normal University, Wuhan, Hubei, P. R. China
| | - Jing-Fang Yang
- Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, Hubei, P. R. China.,International Joint Research Center for Intelligent Biosensor Technology and Health, Central China Normal University, Wuhan, Hubei, P. R. China
| | - Fan Wang
- Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, Hubei, P. R. China.,International Joint Research Center for Intelligent Biosensor Technology and Health, Central China Normal University, Wuhan, Hubei, P. R. China
| | - Ge-Fei Hao
- Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, Hubei, P. R. China.,International Joint Research Center for Intelligent Biosensor Technology and Health, Central China Normal University, Wuhan, Hubei, P. R. China.,State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Research and Development Center for Fine Chemicals, Guizhou University, Guiyang, Guizhou, P. R. China
| | - Guang-Fu Yang
- Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, Hubei, P. R. China.,International Joint Research Center for Intelligent Biosensor Technology and Health, Central China Normal University, Wuhan, Hubei, P. R. China
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4
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Bjarnason S, Ruidiaz SF, McIvor J, Mercadante D, Heidarsson PO. Protein intrinsic disorder on a dynamic nucleosomal landscape. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2021; 183:295-354. [PMID: 34656332 DOI: 10.1016/bs.pmbts.2021.06.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The complex nucleoprotein landscape of the eukaryotic cell nucleus is rich in dynamic proteins that lack a stable three-dimensional structure. Many of these intrinsically disordered proteins operate directly on the first fundamental level of genome compaction: the nucleosome. Here we give an overview of how disordered interactions with and within nucleosomes shape the dynamics, architecture, and epigenetic regulation of the genetic material, controlling cellular transcription patterns. We highlight experimental and computational challenges in the study of protein disorder and illustrate how integrative approaches are increasingly unveiling the fine details of nuclear interaction networks. We finally dissect sequence properties encoded in disordered regions and assess common features of disordered nucleosome-binding proteins. As drivers of many critical biological processes, disordered proteins are integral to a comprehensive molecular view of the dynamic nuclear milieu.
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Affiliation(s)
- Sveinn Bjarnason
- Department of Biochemistry, Science Institute, University of Iceland, Reykjavík, Iceland
| | - Sarah F Ruidiaz
- Department of Biochemistry, Science Institute, University of Iceland, Reykjavík, Iceland
| | - Jordan McIvor
- School of Chemical Science, University of Auckland, Auckland, New Zealand
| | - Davide Mercadante
- School of Chemical Science, University of Auckland, Auckland, New Zealand.
| | - Pétur O Heidarsson
- Department of Biochemistry, Science Institute, University of Iceland, Reykjavík, Iceland.
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5
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Parisi G, Palopoli N, Tosatto SC, Fornasari MS, Tompa P. "Protein" no longer means what it used to. Curr Res Struct Biol 2021; 3:146-152. [PMID: 34308370 PMCID: PMC8283027 DOI: 10.1016/j.crstbi.2021.06.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 06/18/2021] [Accepted: 06/22/2021] [Indexed: 01/02/2023] Open
Abstract
Every biologist knows that the word protein describes a group of macromolecules essential to sustain life on Earth. As biologists, we are invariably trained under a protein paradigm established since the early twentieth century. However, in recent years, the term protein unveiled itself as an euphemism to describe the overwhelming heterogeneity of these compounds. Most of our current studies are targeted on carefully selected subsets of proteins, but we tend to think and write about these as representative of the whole population. Here we discuss how seeking for universal definitions and general rules in any arbitrarily segmented study would be misleading about the conclusions. Of course, it is not our purpose to discourage the use of the word protein. Instead, we suggest to embrace the extended universe of proteins to reach a deeper understanding of their full potential, realizing that the term encompasses a group of molecules very heterogeneous in terms of size, shape, chemistry and functions, i.e. the term protein no longer means what it used to.
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Affiliation(s)
- Gustavo Parisi
- Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes, CONICET, Bernal, Buenos Aires, Argentina
| | - Nicolas Palopoli
- Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes, CONICET, Bernal, Buenos Aires, Argentina
| | | | - María Silvina Fornasari
- Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes, CONICET, Bernal, Buenos Aires, Argentina
| | - Peter Tompa
- VIB-VUB Center for Structural Biology (CSB), Brussels, Belgium
- Structural Biology Brussels (SBB), Vrije Universiteit Brussel (VUB), Brussels, Belgium
- Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary
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6
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Suetake I, Nakazawa S, Sato K, Mutoh R, Mishima Y, Kawakami T, Takei T, Watanabe M, Sakai N, Fujiwara T, Takui T, Miyata M, Shinohara A, Hojo H, Arata T. Structural dynamics of the chromo-shadow domain and chromodomain of HP1 bound to histone H3K9 methylated peptide, as measured by site-directed spin-labeling EPR spectroscopy. Biochem Biophys Res Commun 2021; 567:42-48. [PMID: 34139556 DOI: 10.1016/j.bbrc.2021.06.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Accepted: 06/03/2021] [Indexed: 10/21/2022]
Abstract
The structural dynamics of the chromo-shadow domain (CSD) and chromodomain (CD) of human HP1 proteins essential for heterochromatin formation were investigated at the nanosecond and nanometer scales by site-directed spin labeling electron paramagnetic resonance and pulsed double resonance spectroscopy. Distance measurements showed that the spin-labeled CSD of human HP1α and HP1γ tightly dimerizes. Unlike CD-CD interaction observed in fission yeast HP1 in an inactivated state (Canzio et al., 2013), the two CDs of HP1α and HP1γ were spatially separated from each other, dynamically mobile, and ready for a Brownian search for H3K9-tri-methyl(me3) on histones. Complex formation of the CD with H3K9me3 slowed dynamics of the domain due to a decreased diffusion constant. CSD mobility was significantly (∼1.3-fold) lower in full-length HP1α than in HP1γ, suggesting that the immobilized conformation of human HP1α shows an auto-inactivated state. Differential properties of HP1α and HP1γ to form the inactive conformation could be relevant to its physiological role in the heterochromatin formation in a cell.
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Affiliation(s)
- Isao Suetake
- Institute for Protein Research, Osaka University, Osaka, 565-0871, Japan; Center for Twin Research, Graduate School of Medicine, Osaka University, Osaka, 565-0871, Japan; Department of Nutritional Sciences, Graduate School of Nutritional Sciences, Nakamura Gakuen University, Fukuoka, 814-0198, Japan.
| | - Shigeaki Nakazawa
- Department of Chemistry and Molecular Materials Sciences, Graduate School of Science, Osaka City University, Osaka, 558-8585, Japan
| | - Kazunobu Sato
- Department of Chemistry and Molecular Materials Sciences, Graduate School of Science, Osaka City University, Osaka, 558-8585, Japan
| | - Risa Mutoh
- Department of Applied Physics, Faculty of Science, Fukuoka University, Fukuoka, 814-0180, Japan
| | - Yuichi Mishima
- Institute for Protein Research, Osaka University, Osaka, 565-0871, Japan
| | - Toru Kawakami
- Institute for Protein Research, Osaka University, Osaka, 565-0871, Japan
| | - Toshiki Takei
- Institute for Protein Research, Osaka University, Osaka, 565-0871, Japan
| | - Mikio Watanabe
- Center for Twin Research, Graduate School of Medicine, Osaka University, Osaka, 565-0871, Japan
| | - Norio Sakai
- Center for Twin Research, Graduate School of Medicine, Osaka University, Osaka, 565-0871, Japan
| | | | - Takeji Takui
- Department of Chemistry and Molecular Materials Sciences, Graduate School of Science, Osaka City University, Osaka, 558-8585, Japan
| | - Makoto Miyata
- Department of Biology, Graduate School of Science, Osaka City University, Osaka, 558-8585, Japan
| | - Akira Shinohara
- Institute for Protein Research, Osaka University, Osaka, 565-0871, Japan
| | - Hironobu Hojo
- Institute for Protein Research, Osaka University, Osaka, 565-0871, Japan
| | - Toshiaki Arata
- Institute for Protein Research, Osaka University, Osaka, 565-0871, Japan; Department of Biology, Graduate School of Science, Osaka City University, Osaka, 558-8585, Japan.
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7
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Oki M, Masai H. Regulation of HP1 protein by phosphorylation during transcriptional repression and cell cycle. J Biochem 2021; 169:629-632. [PMID: 33772590 DOI: 10.1093/jb/mvab040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 03/11/2021] [Indexed: 11/12/2022] Open
Abstract
HP1 (Heterochromatin Protein 1), a key factor for the formation of heterochromatin, binds to the methylated lysine 9 of histone H3 (H3K9me), and represses transcription. While the H3K9me mark and HP1 binding are thought to be faithfully propagated to daughter cells, the heterochromatin structure could be dynamically regulated during cell cycle. As evidenced by the well-known phenomenon called Position Effect Variegation (PEV), heterochromatin structure is dynamically and stochastically altered during developmental processes, and thus the expression of genes within or in the vicinity of heterochromatin could be affected by mutations in factors regulating DNA replication as well as by other epigenetic factors. Recent reports show that HP1 also plays an important role in the maintenance and transmission of chromosomes. Like many other factors ensuring faithful chromosome segregation, HP1 family proteins are subjected to posttranslational modifications, most notably phosphorylation, in a cell-cycle dependent manner. Recent studies identified a conserved phosphorylation site that profoundly affects the functions of HP1 during mitotic phase. In this commentary, we discuss dynamic regulation of HP1 protein by phosphorylation during transcriptional repression and cell cycle.
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Affiliation(s)
- Masaya Oki
- Department of Applied Chemistry and Biotechnology, Graduate School of Engineering, University of Fukui, Fukui, JAPAN
| | - Hisao Masai
- Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo, 156-8506, JAPAN, Tel: 81-3-5316-3220
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8
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Palopoli N, Marchetti J, Monzon AM, Zea DJ, Tosatto SCE, Fornasari MS, Parisi G. Intrinsically Disordered Protein Ensembles Shape Evolutionary Rates Revealing Conformational Patterns. J Mol Biol 2020; 433:166751. [PMID: 33310020 DOI: 10.1016/j.jmb.2020.166751] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 12/01/2020] [Accepted: 12/05/2020] [Indexed: 10/22/2022]
Abstract
Intrinsically disordered proteins (IDPs) lack stable tertiary structure under physiological conditions. The unique composition and complex dynamical behaviour of IDPs make them a challenge for structural biology and molecular evolution studies. Using NMR ensembles, we found that IDPs evolve under a strong site-specific evolutionary rate heterogeneity, mainly originated by different constraints derived from their inter-residue contacts. Evolutionary rate profiles correlate with the experimentally observed conformational diversity of the protein, allowing the description of different conformational patterns possibly related to their structure-function relationships. The correlation between evolutionary rates and contact information improves when structural information is taken not from any individual conformer or the whole ensemble, but from combining a limited number of conformers. Our results suggest that residue contacts in disordered regions constrain evolutionary rates to conserve the dynamic behaviour of the ensemble and that evolutionary rates can be used as a proxy for the conformational diversity of IDPs.
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Affiliation(s)
- Nicolas Palopoli
- Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes, CONICET, Bernal, Buenos Aires, Argentina
| | - Julia Marchetti
- Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes, CONICET, Bernal, Buenos Aires, Argentina
| | | | - Diego J Zea
- Sorbonne Université, CNRS, IBPS, Laboratoire de Biologie Computationnelle et Quantitative (LCQB), Paris, France
| | | | - Maria S Fornasari
- Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes, CONICET, Bernal, Buenos Aires, Argentina
| | - Gustavo Parisi
- Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes, CONICET, Bernal, Buenos Aires, Argentina.
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9
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Pokorná P, Krepl M, Šponer J. Residues flanking the ARK me3T/S motif allow binding of diverse targets to the HP1 chromodomain: Insights from molecular dynamics simulations. Biochim Biophys Acta Gen Subj 2020; 1865:129771. [PMID: 33153976 DOI: 10.1016/j.bbagen.2020.129771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 09/15/2020] [Accepted: 10/20/2020] [Indexed: 11/28/2022]
Abstract
BACKGROUND The chromodomain (CD) of HP1 proteins is an established H3K9me3 reader that also binds H1, EHMT2 and H3K23 lysine-methylated targets. Structural experiments have provided atomistic pictures of its recognition of the conserved ARKme3S/T motif, but structural dynamics' contribution to the recognition may have been masked by ensemble averaging. METHODS We acquired ~350 μs of explicit solvent molecular dynamics (MD) simulations of the CD domain interacting with several peptides using the latest AMBER force fields. RESULTS The simulations reproduced the experimentally observed static binding patterns well but also revealed visible structural dynamics at the interfaces. While the buried K0me3 and A-2 target residues are tightly bound, several flanking sidechains sample diverse sites on the CD surface. Different amino acid positions of the targets can substitute for each other by forming mutually replaceable interactions with CD, thereby explaining the lack of strict requirement for cationic H3 target residues at the -3 position. The Q-4 residue of H3 targets further stabilizes the binding. The recognition pattern of the H3K23 ATKme3A motif, for which no structure is available, is predicted. CONCLUSIONS The CD reads a longer target segment than previously thought, ranging from positions -7 to +3. The CD anionic clamp can be neutralized not only by the -3 and -1 residues, but also by -7, -6, -5 and +3 residues. GENERAL SIGNIFICANCE Structural dynamics, not immediately apparent from the structural data, contribute to molecular recognition between the HP1 CD domain and its targets. Mutual replaceability of target residues increases target sequence flexibility.
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Affiliation(s)
- Pavlína Pokorná
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65 Brno, Czech Republic; National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic.
| | - Miroslav Krepl
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65 Brno, Czech Republic
| | - Jiří Šponer
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65 Brno, Czech Republic.
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10
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How HP1 Post-Translational Modifications Regulate Heterochromatin Formation and Maintenance. Cells 2020; 9:cells9061460. [PMID: 32545538 PMCID: PMC7349378 DOI: 10.3390/cells9061460] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 06/10/2020] [Accepted: 06/11/2020] [Indexed: 12/12/2022] Open
Abstract
Heterochromatin Protein 1 (HP1) is a highly conserved protein that has been used as a classic marker for heterochromatin. HP1 binds to di- and tri-methylated histone H3K9 and regulates heterochromatin formation, functions and structure. Besides the well-established phosphorylation of histone H3 Ser10 that has been shown to modulate HP1 binding to chromatin, several studies have recently highlighted the importance of HP1 post-translational modifications and additional epigenetic features for the modulation of HP1-chromatin binding ability and heterochromatin formation. In this review, we summarize the recent literature of HP1 post-translational modifications that have contributed to understand how heterochromatin is formed, regulated and maintained.
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11
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Kumar A, Kono H. Heterochromatin protein 1 (HP1): interactions with itself and chromatin components. Biophys Rev 2020; 12:387-400. [PMID: 32144738 PMCID: PMC7242596 DOI: 10.1007/s12551-020-00663-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 02/23/2020] [Indexed: 12/12/2022] Open
Abstract
Isoforms of heterochromatin protein 1 (HP1) have been known to perform a multitude of functions ranging from gene silencing, gene activation to cell cycle regulation, and cell differentiation. This functional diversity arises from the dissimilarities coded in protein sequence which confers different biophysical and biochemical properties to individual structural elements of HP1 and thereby different behavior and interaction patterns. Hence, an understanding of various interactions of the structural elements of HP1 will be of utmost importance to better elucidate chromatin dynamics in its presence. In this review, we have gathered available information about interactions of HP1 both within and with itself as well as with chromatin elements. Also, the possible implications of these interactions are discussed.
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Affiliation(s)
- Amarjeet Kumar
- Molecular Modelling and Simulation (MMS) Group, Institute for Quantum Life Science (iQLS), National Institutes for Quantum and Radiological Science and Technology (QST), Kizugawa, Kyoto, 619-0215, Japan
| | - Hidetoshi Kono
- Molecular Modelling and Simulation (MMS) Group, Institute for Quantum Life Science (iQLS), National Institutes for Quantum and Radiological Science and Technology (QST), Kizugawa, Kyoto, 619-0215, Japan.
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12
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Mayanagi K, Saikusa K, Miyazaki N, Akashi S, Iwasaki K, Nishimura Y, Morikawa K, Tsunaka Y. Structural visualization of key steps in nucleosome reorganization by human FACT. Sci Rep 2019; 9:10183. [PMID: 31308435 PMCID: PMC6629675 DOI: 10.1038/s41598-019-46617-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Accepted: 07/02/2019] [Indexed: 12/30/2022] Open
Abstract
Facilitates chromatin transcription (FACT) is a histone chaperone, which accomplishes both nucleosome assembly and disassembly. Our combined cryo-electron microscopy (EM) and native mass spectrometry (MS) studies revealed novel key steps of nucleosome reorganization conducted by a Mid domain and its adjacent acidic AID segment of human FACT. We determined three cryo-EM structures of respective octasomes complexed with the Mid-AID and AID regions, and a hexasome alone. We discovered extensive contacts between a FACT region and histones H2A, H2B, and H3, suggesting that FACT is competent to direct functional replacement of a nucleosomal DNA end by its phosphorylated AID segment (pAID). Mutational assays revealed that the aromatic and phosphorylated residues within pAID are essential for octasome binding. The EM structure of the hexasome, generated by the addition of Mid-pAID or pAID, indicated that the dissociation of H2A-H2B dimer causes significant alteration from the canonical path of the nucleosomal DNA.
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Affiliation(s)
- Kouta Mayanagi
- Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka-shi, Fukuoka, 812-8582, Japan.
| | - Kazumi Saikusa
- Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8526, Japan
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan
- National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki, 305-8563, Japan
| | - Naoyuki Miyazaki
- Laboratory of Protein Synthesis and Expression, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Satoko Akashi
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan
| | - Kenji Iwasaki
- Laboratory of Protein Synthesis and Expression, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
- Life Science Center for Survival Dynamics Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8577, Japan
| | - Yoshifumi Nishimura
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan
| | - Kosuke Morikawa
- Department of Gene Mechanisms, Graduate School of Biostudies, Kyoto University, Yoshida-konoemachi, Sakyo-ku, Kyoto, 606-8501, Japan.
| | - Yasuo Tsunaka
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, 230-0045, Japan.
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13
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Nishibuchi G, Machida S, Nakagawa R, Yoshimura Y, Hiragami-Hamada K, Abe Y, Kurumizaka H, Tagami H, Nakayama JI. Mitotic phosphorylation of HP1α regulates its cell cycle-dependent chromatin binding. J Biochem 2018; 165:433-446. [DOI: 10.1093/jb/mvy117] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 12/14/2018] [Indexed: 11/13/2022] Open
Affiliation(s)
- Gohei Nishibuchi
- Graduate School of Natural Sciences, Nagoya City University, Yamanohata 1, Mizuho-cho, Mizuho-ku, Nagoya, Japan
| | - Shinichi Machida
- Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, Shinjuku-ku, Tokyo, Japan
| | - Reiko Nakagawa
- Laboratory for Phyloinformatics, RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe, Japan
| | - Yuriko Yoshimura
- Division of Chromatin Regulation, National Institute for Basic Biology, Nishigonaka 38, Myodaiji, Okazaki, Japan
| | - Kyoko Hiragami-Hamada
- Division of Chromatin Regulation, National Institute for Basic Biology, Nishigonaka 38, Myodaiji, Okazaki, Japan
- Department of Basic Biology, School of Life Science, The Graduate University for Advanced Studies (SOKENDAI), Nishigonaka 38, Myodaiji, Okazaki, Japan
| | - Yusuke Abe
- Division of Experimental Pathology, Cancer Institute of the Japanese Foundation for Cancer Research, Koto-ku, Tokyo, Japan
| | - Hitoshi Kurumizaka
- Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, Shinjuku-ku, Tokyo, Japan
- Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Hideaki Tagami
- Graduate School of Natural Sciences, Nagoya City University, Yamanohata 1, Mizuho-cho, Mizuho-ku, Nagoya, Japan
| | - Jun-ichi Nakayama
- Graduate School of Natural Sciences, Nagoya City University, Yamanohata 1, Mizuho-cho, Mizuho-ku, Nagoya, Japan
- Division of Chromatin Regulation, National Institute for Basic Biology, Nishigonaka 38, Myodaiji, Okazaki, Japan
- Department of Basic Biology, School of Life Science, The Graduate University for Advanced Studies (SOKENDAI), Nishigonaka 38, Myodaiji, Okazaki, Japan
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14
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Li Z, Kono H. Investigating the Influence of Arginine Dimethylation on Nucleosome Dynamics Using All-Atom Simulations and Kinetic Analysis. J Phys Chem B 2018; 122:9625-9634. [DOI: 10.1021/acs.jpcb.8b05067] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Zhenhai Li
- Molecular Modeling and Simulation (MMS) Group, National Institutes for Quantum and Radiological Science and Technology (QST), 8-1-7, Umemidai, Kizugawa, Kyoto 619-0215, Japan
| | - Hidetoshi Kono
- Molecular Modeling and Simulation (MMS) Group, National Institutes for Quantum and Radiological Science and Technology (QST), 8-1-7, Umemidai, Kizugawa, Kyoto 619-0215, Japan
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15
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Watanabe S, Mishima Y, Shimizu M, Suetake I, Takada S. Interactions of HP1 Bound to H3K9me3 Dinucleosome by Molecular Simulations and Biochemical Assays. Biophys J 2018; 114:2336-2351. [PMID: 29685391 PMCID: PMC6129468 DOI: 10.1016/j.bpj.2018.03.025] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 02/27/2018] [Accepted: 03/26/2018] [Indexed: 01/01/2023] Open
Abstract
Heterochromatin protein 1 (HP1), associated with heterochromatin formation, recognizes an epigenetically repressive marker, trimethylated lysine 9 in histone H3 (H3K9me3), and generally contributes to long-term silencing. How HP1 induces heterochromatin is not fully understood. Recent experiments suggested that not one, but two nucleosomes provide a platform for this recognition. Integrating previous and new biochemical assays with computational modeling, we provide near-atomic structural models for HP1 binding to the dinucleosomes. We found that the dimeric HP1α tends to bind two H3K9me3s that are in adjacent nucleosomes, thus bridging two nucleosomes. We identified, to our knowledge, a novel DNA binding motif in the hinge region that is specific to HP1α and is essential for recognizing the H3K9me3 sites of two nucleosomes. An HP1 isoform, HP1γ, does not easily bridge two nucleosomes in extended conformations because of the absence of the above binding motif and its shorter hinge region. We propose a molecular mechanism for chromatin structural changes caused by HP1.
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Affiliation(s)
- Shuhei Watanabe
- Department of Biophysics, Graduate School of Science, Kyoto University, Kitashirakawa, Sakyo, Kyoto, Japan
| | - Yuichi Mishima
- Institute for Protein Research, Osaka University, Suita, Osaka, Japan
| | - Masahiro Shimizu
- Department of Biophysics, Graduate School of Science, Kyoto University, Kitashirakawa, Sakyo, Kyoto, Japan
| | - Isao Suetake
- Institute for Protein Research, Osaka University, Suita, Osaka, Japan; College of Nutrition, Koshien University, Takarazuka, Japan.
| | - Shoji Takada
- Department of Biophysics, Graduate School of Science, Kyoto University, Kitashirakawa, Sakyo, Kyoto, Japan.
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16
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Kawaguchi T, Machida S, Kurumizaka H, Tagami H, Nakayama JI. Phosphorylation of CBX2 controls its nucleosome-binding specificity. J Biochem 2017; 162:343-355. [PMID: 28992316 DOI: 10.1093/jb/mvx040] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Accepted: 05/22/2017] [Indexed: 01/08/2023] Open
Abstract
Chromobox 2 (CBX2), a component of polycomb repressive complex 1 (PRC1), binds lysine 27-methylated histone H3 (H3K27me3) via its chromodomain (CD) and plays a critical role in repressing developmentally regulated genes. The phosphorylation of CBX2 has been described in several studies, but the biological implications of this modification remain largely elusive. Here, we show that CBX2's phosphorylation plays an important role in its nucleosome binding. CBX2 is stably phosphorylated in vivo, and domain analysis showed that residues in CBX2's serine-rich (SR) region are the predominant phosphorylation sites. The serine residues in an SR region followed by an acidic-residue (AR) cluster coincide with the consensus target of casein kinase II (CK2), and CK2 efficiently phosphorylated the SR region in vitro. A nucleosome pull-down assay revealed that CK2-phosphorylated CBX2 had a high specificity for H3K27me3-modified nucleosomes. An electrophoretic mobility-shift assay showed that CK2-mediated phosphorylation diminished CBX2's AT-hook-associated DNA-binding activity. Mutant CBX2 lacking the SR region or its neighboring AR cluster failed to repress the transcription of p21, a gene targeted by PRC1. These results suggest that CBX2's phosphorylation is critical for its transcriptional repression of target genes.
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Affiliation(s)
- Takayuki Kawaguchi
- Division of Chromatin Regulation, National Institute for Basic Biology, Nishigonaka 38, Myodaiji, Okazaki, Aichi 444-8585, Japan.,Graduate School of Natural Sciences, Nagoya City University, 1 Yamanohata, Mizuho-cho, Mizuho-ku, Nagoya, Aichi 467-8501, Japan
| | - Shinichi Machida
- Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Hitoshi Kurumizaka
- Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Hideaki Tagami
- Graduate School of Natural Sciences, Nagoya City University, 1 Yamanohata, Mizuho-cho, Mizuho-ku, Nagoya, Aichi 467-8501, Japan
| | - Jun-Ichi Nakayama
- Division of Chromatin Regulation, National Institute for Basic Biology, Nishigonaka 38, Myodaiji, Okazaki, Aichi 444-8585, Japan.,Graduate School of Natural Sciences, Nagoya City University, 1 Yamanohata, Mizuho-cho, Mizuho-ku, Nagoya, Aichi 467-8501, Japan
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17
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Bryan LC, Weilandt DR, Bachmann AL, Kilic S, Lechner CC, Odermatt PD, Fantner GE, Georgeon S, Hantschel O, Hatzimanikatis V, Fierz B. Single-molecule kinetic analysis of HP1-chromatin binding reveals a dynamic network of histone modification and DNA interactions. Nucleic Acids Res 2017; 45:10504-10517. [PMID: 28985346 PMCID: PMC5737501 DOI: 10.1093/nar/gkx697] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 07/27/2017] [Indexed: 12/20/2022] Open
Abstract
Chromatin recruitment of effector proteins involved in gene regulation depends on multivalent interaction with histone post-translational modifications (PTMs) and structural features of the chromatin fiber. Due to the complex interactions involved, it is currently not understood how effectors dynamically sample the chromatin landscape. Here, we dissect the dynamic chromatin interactions of a family of multivalent effectors, heterochromatin protein 1 (HP1) proteins, using single-molecule fluorescence imaging and computational modeling. We show that the three human HP1 isoforms are recruited and retained on chromatin by a dynamic exchange between histone PTM and DNA bound states. These interactions depend on local chromatin structure, the HP1 isoforms as well as on PTMs on HP1 itself. Of the HP1 isoforms, HP1α exhibits the longest residence times and fastest binding rates due to DNA interactions in addition to PTM binding. HP1α phosphorylation further increases chromatin retention through strengthening of multivalency while reducing DNA binding. As DNA binding in combination with specific PTM recognition is found in many chromatin effectors, we propose a general dynamic capture mechanism for effector recruitment. Multiple weak protein and DNA interactions result in a multivalent interaction network that targets effectors to a specific chromatin modification state, where their activity is required.
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Affiliation(s)
- Louise C Bryan
- Laboratory of Biophysical Chemistry of Macromolecules, Institute of Chemical Sciences and Engineering (ISIC), Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Daniel R Weilandt
- Laboratory of Computational Systems Biotechnology, ISIC, EPFL, 1015 Lausanne, Switzerland
| | - Andreas L Bachmann
- Laboratory of Biophysical Chemistry of Macromolecules, Institute of Chemical Sciences and Engineering (ISIC), Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Sinan Kilic
- Laboratory of Biophysical Chemistry of Macromolecules, Institute of Chemical Sciences and Engineering (ISIC), Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Carolin C Lechner
- Laboratory of Biophysical Chemistry of Macromolecules, Institute of Chemical Sciences and Engineering (ISIC), Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Pascal D Odermatt
- Laboratory for Bio- and Nano instrumentation, Institute of Bioengineering, EPFL, 1015 Lausanne, Switzerland
| | - Georg E Fantner
- Laboratory for Bio- and Nano instrumentation, Institute of Bioengineering, EPFL, 1015 Lausanne, Switzerland
| | - Sandrine Georgeon
- ISREC foundation chair in translational oncology, School of Life Sciences, EPFL, 1015 Lausanne, Switzerland
| | - Oliver Hantschel
- ISREC foundation chair in translational oncology, School of Life Sciences, EPFL, 1015 Lausanne, Switzerland
| | - Vassily Hatzimanikatis
- Laboratory of Computational Systems Biotechnology, ISIC, EPFL, 1015 Lausanne, Switzerland
| | - Beat Fierz
- Laboratory of Biophysical Chemistry of Macromolecules, Institute of Chemical Sciences and Engineering (ISIC), Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
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18
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Wiley EA, Horrell S, Yoshino A, Schornak CC, Bagnani C, Chalker DL. Diversification of HP1-like Chromo Domain Proteins in Tetrahymena thermophila. J Eukaryot Microbiol 2017; 65:104-116. [PMID: 28692189 PMCID: PMC5762428 DOI: 10.1111/jeu.12443] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 06/23/2017] [Accepted: 06/27/2017] [Indexed: 12/18/2022]
Abstract
Proteins that possess a chromo domain are well-known for their roles in heterochromatin assembly and maintenance. The Heterochromatin Protein 1 (HP1) family, with a chromo domain and carboxy-terminal chromo shadow domain, targets heterochromatin through interaction with histone H3 methylated on lysine 9 (H3K9me2/3). The structural and functional diversity of these proteins observed in both fission yeast and metazoans correlate with chromatin specialization. To expand these studies, we examined chromo domain proteins in the ciliate Tetrahymena thermophila, which has functionally diverse and developmentally regulated heterochromatin domains. We identified thirteen proteins similar to HP1. Together they possess only a fraction of the possible chromo domain subtypes and most lack a recognizable chromo shadow domain. Using fluorescence microscopy to track chromatin localization of tagged proteins through the life cycle, we show evidence that in T. thermophila this family has diversified with biological roles in RNAi-directed DNA elimination, germline genome structure, and somatic heterochromatin. Those proteins with H3K27me3 binding sequence characteristics localize to chromatin in mature nuclei, whereas those with H3K9me2/3 binding characteristics localize to developing nuclei undergoing DNA elimination. Findings point to an expanded and diversified family of chromo domain proteins that parallels heterochromatin diversity in ciliates.
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Affiliation(s)
- Emily A Wiley
- W.M. Keck Science Center of Claremont McKenna, Pitzer, and Scripps Colleges, Claremont, California, 91711
| | - Scott Horrell
- Department of Biology, Washington University, St. Louis, Missouri, 63130
| | - Alyssa Yoshino
- W.M. Keck Science Center of Claremont McKenna, Pitzer, and Scripps Colleges, Claremont, California, 91711
| | - Cara C Schornak
- Department of Biology, Washington University, St. Louis, Missouri, 63130
| | - Claire Bagnani
- W.M. Keck Science Center of Claremont McKenna, Pitzer, and Scripps Colleges, Claremont, California, 91711
| | - Douglas L Chalker
- Department of Biology, Washington University, St. Louis, Missouri, 63130
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19
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Gibbs EB, Cook EC, Showalter SA. Application of NMR to studies of intrinsically disordered proteins. Arch Biochem Biophys 2017; 628:57-70. [PMID: 28502465 DOI: 10.1016/j.abb.2017.05.008] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 05/08/2017] [Accepted: 05/10/2017] [Indexed: 12/20/2022]
Abstract
The prevalence of intrinsically disordered protein regions, particularly in eukaryotic proteins, and their clear functional advantages for signaling and gene regulation have created an imperative for high-resolution structural and mechanistic studies. NMR spectroscopy has played a central role in enhancing not only our understanding of the intrinsically disordered native state, but also how that state contributes to biological function. While pathological functions associated with protein aggregation are well established, it has recently become clear that disordered regions also mediate functionally advantageous assembly into high-order structures that promote the formation of membrane-less sub-cellular compartments and even hydrogels. Across the range of functional assembly states accessed by disordered regions, post-translational modifications and regulatory macromolecular interactions, which can also be investigated by NMR spectroscopy, feature prominently. Here we will explore the many ways in which NMR has advanced our understanding of the physical-chemical phase space occupied by disordered protein regions and provide prospectus for the future role of NMR in this emerging and exciting field.
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Affiliation(s)
- Eric B Gibbs
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA
| | - Erik C Cook
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA
| | - Scott A Showalter
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA; Center for Eukaryotic Gene Regulation, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA.
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20
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du Preez LL, Patterton HG. The effect of epigenetic modifications on the secondary structures and possible binding positions of the N-terminal tail of histone H3 in the nucleosome: a computational study. J Mol Model 2017; 23:137. [PMID: 28353152 PMCID: PMC5391383 DOI: 10.1007/s00894-017-3308-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 03/06/2017] [Indexed: 11/05/2022]
Abstract
The roles of histone tails as substrates for reversible chemical modifications and dynamic cognate surfaces for the binding of regulatory proteins are well established. Despite these crucial roles, experimentally derived knowledge of the structure and possible binding sites of histone tails in chromatin is limited. In this study, we utilized molecular dynamics of isolated histone H3 N-terminal peptides to investigate its structure as a function of post-translational modifications that are known to be associated with defined chromatin states. We observed a structural preference for α-helices in isoforms associated with an inactive chromatin state, while isoforms associated with active chromatin states lacked α-helical content. The physicochemical effect of the post-translational modifications was highlighted by the interaction of arginine side-chains with the phosphorylated serine residues in the inactive isoform. We also showed that the isoforms exhibit different tail lengths, and, using molecular docking of the first 15 N-terminal residues of an H3 isoform, identified potential binding sites between the superhelical gyres on the octamer surface, close to the site of DNA entry/exit in the nucleosome. We discuss the possible functional role of the binding of the H3 tail within the nucleosome on both nucleosome and chromatin structure and stability.
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Affiliation(s)
- Louis L du Preez
- Department of Microbiological, Biochemical and Food Biotechnology, University of the Free State, Bloemfontein, 9301, South Africa
| | - Hugh-G Patterton
- Division of Bioinformatics and Department of Biochemistry, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa.
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