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Bedir M, Outwin E, Colnaghi R, Bassett L, Abramowicz I, O'Driscoll M. A novel role for the peptidyl-prolyl cis-trans isomerase Cyclophilin A in DNA-repair following replication fork stalling via the MRE11-RAD50-NBS1 complex. EMBO Rep 2024; 25:3432-3455. [PMID: 38943005 PMCID: PMC11315929 DOI: 10.1038/s44319-024-00184-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 05/28/2024] [Accepted: 06/05/2024] [Indexed: 06/30/2024] Open
Abstract
Cyclosporin A (CsA) induces DNA double-strand breaks in LIG4 syndrome fibroblasts, specifically upon transit through S-phase. The basis underlying this has not been described. CsA-induced genomic instability may reflect a direct role of Cyclophilin A (CYPA) in DNA repair. CYPA is a peptidyl-prolyl cis-trans isomerase (PPI). CsA inhibits the PPI activity of CYPA. Using an integrated approach involving CRISPR/Cas9-engineering, siRNA, BioID, co-immunoprecipitation, pathway-specific DNA repair investigations as well as protein expression interaction analysis, we describe novel impacts of CYPA loss and inhibition on DNA repair. We characterise a direct CYPA interaction with the NBS1 component of the MRE11-RAD50-NBS1 complex, providing evidence that CYPA influences DNA repair at the level of DNA end resection. We define a set of genetic vulnerabilities associated with CYPA loss and inhibition, identifying DNA replication fork protection as an important determinant of viability. We explore examples of how CYPA inhibition may be exploited to selectively kill cancers sharing characteristic genomic instability profiles, including MYCN-driven Neuroblastoma, Multiple Myeloma and Chronic Myelogenous Leukaemia. These findings propose a repurposing strategy for Cyclophilin inhibitors.
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Affiliation(s)
- Marisa Bedir
- Human DNA Damage Response Disorders Group, Genome Damage & Stability Centre, University of Sussex, Brighton, BN1 9RQ, UK
| | - Emily Outwin
- Human DNA Damage Response Disorders Group, Genome Damage & Stability Centre, University of Sussex, Brighton, BN1 9RQ, UK
| | - Rita Colnaghi
- Human DNA Damage Response Disorders Group, Genome Damage & Stability Centre, University of Sussex, Brighton, BN1 9RQ, UK
| | - Lydia Bassett
- Human DNA Damage Response Disorders Group, Genome Damage & Stability Centre, University of Sussex, Brighton, BN1 9RQ, UK
| | - Iga Abramowicz
- Human DNA Damage Response Disorders Group, Genome Damage & Stability Centre, University of Sussex, Brighton, BN1 9RQ, UK
| | - Mark O'Driscoll
- Human DNA Damage Response Disorders Group, Genome Damage & Stability Centre, University of Sussex, Brighton, BN1 9RQ, UK.
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2
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Lorković ZJ, Klingenbrunner M, Cho CH, Berger F. Identification of plants' functional counterpart of the metazoan mediator of DNA Damage checkpoint 1. EMBO Rep 2024; 25:1936-1961. [PMID: 38438802 PMCID: PMC11014961 DOI: 10.1038/s44319-024-00107-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 02/13/2024] [Accepted: 02/19/2024] [Indexed: 03/06/2024] Open
Abstract
Induction of DNA damage triggers rapid phosphorylation of the histone H2A.X (γH2A.X). In animals, mediator of DNA damage checkpoint 1 (MDC1) binds γH2A.X through a tandem BRCA1 carboxyl-terminal (tBRCT) domain and mediates recruitment of downstream effectors of DNA damage response (DDR). However, readers of this modification in plants have remained elusive. We show that from the Arabidopsis BRCT domain proteome, BCP1-4 proteins with tBRCT domains are involved in DDR. Through its tBRCT domain BCP4 binds γH2A.X in vitro and localizes to DNA damage-induced foci in an H2A.X-dependent manner. BCP4 also contains a domain that interacts directly with NBS1 and thus acts as a functional counterpart of MDC1. We also show that BCP1, that contains two tBRCT domains, co-localizes with γH2A.X but it does not bind γH2A.X suggesting functional similarity with human PAXIP1. A phylogenetic analysis supports that PAXIP1 and MDC1 in metazoa and their plant counterparts evolved independently from common ancestors with tBRCT domains. Collectively, our study reveals missing components and provides mechanistic and evolutionary insights into plant DDR.
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Affiliation(s)
- Zdravko J Lorković
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria.
| | - Michael Klingenbrunner
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Chung Hyun Cho
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria
| | - Frédéric Berger
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria.
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3
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El‐Kamand S, Adams MN, Matthews JM, Du Plessis M, Crossett B, Connolly A, Breen N, Dudley A, Richard DJ, Gamsjaeger R, Cubeddu L. The molecular details of a novel phosphorylation-dependent interaction between MRN and the SOSS complex. Protein Sci 2023; 32:e4782. [PMID: 37705456 PMCID: PMC10521234 DOI: 10.1002/pro.4782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 08/08/2023] [Accepted: 09/11/2023] [Indexed: 09/15/2023]
Abstract
The repair of double-strand DNA breaks (DSBs) by homologous recombination is crucial in the maintenance of genome integrity. While the key role of the Mre11-Rad50-Nbs1 (MRN) complex in repair is well known, hSSB1 (SOSSB and OBFC2B), one of the main components of the sensor of single-stranded DNA (SOSS) protein complex, has also been shown to rapidly localize to DSB breaks and promote repair. We have previously demonstrated that hSSB1 binds directly to Nbs1, a component of the MRN complex, in a DNA damage-independent manner. However, recruitment of the MRN complex has also been demonstrated by an interaction between Integrator Complex Subunit 3 (INTS3; also known as SOSSA), another member of the SOSS complex, and Nbs1. In this study, we utilize a combined approach of in silico, biochemical, and functional experiments to uncover the molecular details of INTS3 binding to Nbs1. We demonstrate that the forkhead-associated domain of Nbs1 interacts with INTS3 via phosphorylation-dependent binding to INTS3 at Threonine 592, with contributions from Serine 590. Based on these data, we propose a model of MRN recruitment to a DSB via INTS3.
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Affiliation(s)
- Serene El‐Kamand
- School of ScienceWestern Sydney UniversityPenrithNew South WalesAustralia
| | - Mark N. Adams
- Centre for Genomics and Personalised Health, School of Biomedical Sciences, Faculty of HealthTranslational Research Institute, Queensland University of TechnologyBrisbaneQueenslandAustralia
| | - Jacqueline M. Matthews
- School of Life and Environmental SciencesUniversity of SydneySydneyNew South WalesAustralia
| | | | - Ben Crossett
- Sydney Mass SpectrometryUniversity of SydneySydneyNew South WalesAustralia
| | - Angela Connolly
- Sydney Mass SpectrometryUniversity of SydneySydneyNew South WalesAustralia
| | - Natasha Breen
- School of ScienceWestern Sydney UniversityPenrithNew South WalesAustralia
| | - Alexander Dudley
- School of ScienceWestern Sydney UniversityPenrithNew South WalesAustralia
| | - Derek J. Richard
- Centre for Genomics and Personalised Health, School of Biomedical Sciences, Faculty of HealthTranslational Research Institute, Queensland University of TechnologyBrisbaneQueenslandAustralia
| | - Roland Gamsjaeger
- School of ScienceWestern Sydney UniversityPenrithNew South WalesAustralia
- School of Life and Environmental SciencesUniversity of SydneySydneyNew South WalesAustralia
| | - Liza Cubeddu
- School of ScienceWestern Sydney UniversityPenrithNew South WalesAustralia
- School of Life and Environmental SciencesUniversity of SydneySydneyNew South WalesAustralia
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4
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Mre11-Rad50: the DNA end game. Biochem Soc Trans 2023; 51:527-538. [PMID: 36892213 DOI: 10.1042/bst20220754] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 02/09/2023] [Accepted: 02/17/2023] [Indexed: 03/10/2023]
Abstract
The Mre11-Rad50-(Nbs1/Xrs2) complex is an evolutionarily conserved factor for the repair of DNA double-strand breaks and other DNA termini in all kingdoms of life. It is an intricate DNA associated molecular machine that cuts, among other functions, a large variety of free and obstructed DNA termini for DNA repair by end joining or homologous recombination, yet leaves undamaged DNA intact. Recent years have brought progress in both the structural and functional analyses of Mre11-Rad50 orthologs, revealing mechanisms of DNA end recognition, endo/exonuclease activities, nuclease regulation and DNA scaffolding. Here, I review our current understanding and recent progress on the functional architecture Mre11-Rad50 and how this chromosome associated coiled-coil ABC ATPase acts as DNA topology specific endo-/exonuclease.
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5
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Dullovi A, Ozgencil M, Rajvee V, Tse WY, Cutillas PR, Martin SA, Hořejší Z. Microtubule-associated proteins MAP7 and MAP7D1 promote DNA double-strand break repair in the G1 cell cycle phase. iScience 2023; 26:106107. [PMID: 36852271 PMCID: PMC9958362 DOI: 10.1016/j.isci.2023.106107] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 12/12/2022] [Accepted: 01/27/2023] [Indexed: 02/04/2023] Open
Abstract
The DNA-damage response is a complex signaling network that guards genomic integrity. The microtubule cytoskeleton is involved in the repair of DNA double-strand breaks; however, little is known about which cytoskeleton-related proteins are involved in DNA repair and how. Using quantitative proteomics, we discovered that microtubule associated proteins MAP7 and MAP7D1 interact with several DNA repair proteins including DNA double-strand break repair proteins RAD50, BRCA1 and 53BP1. We observed that downregulation of MAP7 and MAP7D1 leads to increased phosphorylation of p53 after γ-irradiation. Moreover, we determined that the downregulation of MAP7D1 leads to a strong G1 arrest and that the downregulation of MAP7 and MAP7D1 in G1 arrested cells negatively affects DNA repair, recruitment of RAD50 to chromatin and localization of 53BP1 to the sites of damage. These findings describe for the first time a novel function of MAP7 and MAP7D1 in cell cycle regulation and repair of DNA double-strand breaks.
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Affiliation(s)
- Arlinda Dullovi
- Centre for Cancer Cell & Molecular Biology, Barts Cancer Institute, Queen Mary University of London, Charterhouse Square, London EC1M 6BQ, UK
| | - Meryem Ozgencil
- Centre for Cancer Cell & Molecular Biology, Barts Cancer Institute, Queen Mary University of London, Charterhouse Square, London EC1M 6BQ, UK
| | - Vinothini Rajvee
- Mass Spectrometry Laboratory, Barts Cancer Institute, Queen Mary University of London, Charterhouse Square, London EC1M 6BQ, UK
| | - Wai Yiu Tse
- Centre for Cancer Cell & Molecular Biology, Barts Cancer Institute, Queen Mary University of London, Charterhouse Square, London EC1M 6BQ, UK
| | - Pedro R. Cutillas
- Centre for Genomics & Computational Biology, Barts Cancer Institute, Queen Mary University of London, Charterhouse Square, London EC1M 6BQ, UK
| | - Sarah A. Martin
- Centre for Cancer Cell & Molecular Biology, Barts Cancer Institute, Queen Mary University of London, Charterhouse Square, London EC1M 6BQ, UK
| | - Zuzana Hořejší
- Centre for Cancer Cell & Molecular Biology, Barts Cancer Institute, Queen Mary University of London, Charterhouse Square, London EC1M 6BQ, UK,Corresponding author
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6
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The Role of Hsp90-R2TP in Macromolecular Complex Assembly and Stabilization. Biomolecules 2022; 12:biom12081045. [PMID: 36008939 PMCID: PMC9406135 DOI: 10.3390/biom12081045] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 07/19/2022] [Accepted: 07/25/2022] [Indexed: 01/27/2023] Open
Abstract
Hsp90 is a ubiquitous molecular chaperone involved in many cell signaling pathways, and its interactions with specific chaperones and cochaperones determines which client proteins to fold. Hsp90 has been shown to be involved in the promotion and maintenance of proper protein complex assembly either alone or in association with other chaperones such as the R2TP chaperone complex. Hsp90-R2TP acts through several mechanisms, such as by controlling the transcription of protein complex subunits, stabilizing protein subcomplexes before their incorporation into the entire complex, and by recruiting adaptors that facilitate complex assembly. Despite its many roles in protein complex assembly, detailed mechanisms of how Hsp90-R2TP assembles protein complexes have yet to be determined, with most findings restricted to proteomic analyses and in vitro interactions. This review will discuss our current understanding of the function of Hsp90-R2TP in the assembly, stabilization, and activity of the following seven classes of protein complexes: L7Ae snoRNPs, spliceosome snRNPs, RNA polymerases, PIKKs, MRN, TSC, and axonemal dynein arms.
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Abdisalaam S, Mukherjee S, Bhattacharya S, Kumari S, Sinha D, Ortega J, Li GM, Sadek H, Krishnan S, Asaithamby A. NBS1-CtIP-mediated DNA end resection suppresses cGAS binding to micronuclei. Nucleic Acids Res 2022; 50:2681-2699. [PMID: 35189637 PMCID: PMC8934670 DOI: 10.1093/nar/gkac079] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 01/12/2022] [Accepted: 01/25/2022] [Indexed: 01/07/2023] Open
Abstract
Cyclic guanosine monophosphate-adenosine monophosphate synthase (cGAS) is activated in cells with defective DNA damage repair and signaling (DDR) factors, but a direct role for DDR factors in regulating cGAS activation in response to micronuclear DNA is still poorly understood. Here, we provide novel evidence that Nijmegen breakage syndrome 1 (NBS1) protein, a well-studied DNA double-strand break (DSB) sensor-in coordination with Ataxia Telangiectasia Mutated (ATM), a protein kinase, and Carboxy-terminal binding protein 1 interacting protein (CtIP), a DNA end resection factor-functions as an upstream regulator that prevents cGAS from binding micronuclear DNA. When NBS1 binds to micronuclear DNA via its fork-head-associated domain, it recruits CtIP and ATM via its N- and C-terminal domains, respectively. Subsequently, ATM stabilizes NBS1's interaction with micronuclear DNA, and CtIP converts DSB ends into single-strand DNA ends; these two key events prevent cGAS from binding micronuclear DNA. Additionally, by using a cGAS tripartite system, we show that cells lacking NBS1 not only recruit cGAS to a major fraction of micronuclear DNA but also activate cGAS in response to these micronuclear DNA. Collectively, our results underscore how NBS1 and its binding partners prevent cGAS from binding micronuclear DNA, in addition to their classical functions in DDR signaling.
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Affiliation(s)
- Salim Abdisalaam
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Shibani Mukherjee
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Souparno Bhattacharya
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Sharda Kumari
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Debapriya Sinha
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Janice Ortega
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Guo-Min Li
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Hesham A Sadek
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Sunil Krishnan
- Department of Radiation Oncology, Mayo Clinic Florida, Jacksonville, FL 32082, USA
| | - Aroumougame Asaithamby
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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8
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Species variations in XRCC1 recruitment strategies for FHA domain-containing proteins. DNA Repair (Amst) 2022; 110:103263. [PMID: 35026705 PMCID: PMC9282668 DOI: 10.1016/j.dnarep.2021.103263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 11/07/2021] [Accepted: 12/21/2021] [Indexed: 02/03/2023]
Abstract
DNA repair scaffolds XRCC1 and XRCC4 utilize a phosphopeptide FHA domain binding motif (FBM) of the form Y-x-x-pS-pT-D-E that supports recruitment of three identified FHA domain-containing DNA repair proteins: polynucleotide kinase/phosphatase (PNKP), aprataxin (APTX), and a third protein, APLF, that functions as a scaffold in support of non-homologous end joining (NHEJ). Mammalian dimeric XRCC4 is able to interact with two of these proteins at any given time, while monomeric XRCC1 binds only one. However, sequence analysis indicates that amphibian and teleost XRCC1 generally contain two FHA binding motifs. X1-FBM1, is similar to the single mammalian XRCC1 FBM and probably functions similarly. X1-FBM2, is more similar to mammalian XRCC4 FBM; it is located closer to the XRCC1 BRCT1 domain and probably is less discriminating among its three likely binding partners. Availability of an additional PNKP or APTX recruitment motif may alleviate the bottleneck that results from using a single FBM motif for recruitment of multiple repair factors. Alternatively, recruitment of APLF by X1-FBM2 may function to rescue a misdirected or unsuccessful SSB repair response by redirecting the damaged DNA to the NHEJ pathway, - a need that results from the ambiguity of the PARP1 signal regarding the nature of the damage. Evaluation of XRCC4 FBMs in acanthomorphs, which account for a majority of the reported teleost sequences, reveals the presence of an additional XRCC4-like paralog, distinct from other previously described members of the XRCC4 superfamily. The FBM is typically absent in acanthomorph XRCC4, but present in the XRCC4-like paralog. Modeling suggests that XRCC4 and its paralog may form homodimers or XRCC4-XRCC4-like heterodimers.
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9
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Giaccherini C, Gaillard P. Control of structure-specific endonucleases during homologous recombination in eukaryotes. Curr Opin Genet Dev 2021; 71:195-205. [PMID: 34624742 DOI: 10.1016/j.gde.2021.09.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 09/10/2021] [Accepted: 09/13/2021] [Indexed: 01/14/2023]
Abstract
Structure-Specific Endonucleases (SSE) are specialized DNA endonucleases that recognize and process DNA secondary structures without any strict dependency on the nucleotide sequence context. This enables them to act virtually anywhere in the genome and to make key contributions to the maintenance of genome stability by removing DNA structures that may stall essential cellular processes such as DNA replication, transcription, repair and chromosome segregation. During repair of double strand breaks by homologous recombination mechanisms, DNA secondary structures are formed and processed in a timely manner. Their homeostasis relies on the combined action of helicases, SSE and topoisomerases. In this review, we focus on how SSE contribute to DNA end resection, single-strand annealing and double-strand break repair, with an emphasis on how their action is fine-tuned in those processes.
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Affiliation(s)
- C Giaccherini
- Centre de Recherche en Cancérologie de Marseille, CRCM, Inserm, CNRS, Aix-Marseille Université, Institut Paoli-Calmettes, Marseille, France
| | - Phl Gaillard
- Centre de Recherche en Cancérologie de Marseille, CRCM, Inserm, CNRS, Aix-Marseille Université, Institut Paoli-Calmettes, Marseille, France.
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10
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Frock RL, Sadeghi C, Meng J, Wang JL. DNA End Joining: G0-ing to the Core. Biomolecules 2021; 11:biom11101487. [PMID: 34680120 PMCID: PMC8533500 DOI: 10.3390/biom11101487] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 10/05/2021] [Accepted: 10/06/2021] [Indexed: 12/28/2022] Open
Abstract
Humans have evolved a series of DNA double-strand break (DSB) repair pathways to efficiently and accurately rejoin nascently formed pairs of double-stranded DNA ends (DSEs). In G0/G1-phase cells, non-homologous end joining (NHEJ) and alternative end joining (A-EJ) operate to support covalent rejoining of DSEs. While NHEJ is predominantly utilized and collaborates extensively with the DNA damage response (DDR) to support pairing of DSEs, much less is known about A-EJ collaboration with DDR factors when NHEJ is absent. Non-cycling lymphocyte progenitor cells use NHEJ to complete V(D)J recombination of antigen receptor genes, initiated by the RAG1/2 endonuclease which holds its pair of targeted DSBs in a synapse until each specified pair of DSEs is handed off to the NHEJ DSB sensor complex, Ku. Similar to designer endonuclease DSBs, the absence of Ku allows for A-EJ to access RAG1/2 DSEs but with random pairing to complete their repair. Here, we describe recent insights into the major phases of DSB end joining, with an emphasis on synapsis and tethering mechanisms, and bring together new and old concepts of NHEJ vs. A-EJ and on RAG2-mediated repair pathway choice.
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11
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Ye Z, Xu S, Shi Y, Bacolla A, Syed A, Moiani D, Tsai CL, Shen Q, Peng G, Leonard PG, Jones DE, Wang B, Tainer JA, Ahmed Z. GRB2 enforces homology-directed repair initiation by MRE11. SCIENCE ADVANCES 2021; 7:7/32/eabe9254. [PMID: 34348893 PMCID: PMC8336959 DOI: 10.1126/sciadv.abe9254] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 06/17/2021] [Indexed: 05/10/2023]
Abstract
DNA double-strand break (DSB) repair is initiated by MRE11 nuclease for both homology-directed repair (HDR) and alternative end joining (Alt-EJ). Here, we found that GRB2, crucial to timely proliferative RAS/MAPK pathway activation, unexpectedly forms a biophysically validated GRB2-MRE11 (GM) complex for efficient HDR initiation. GRB2-SH2 domain targets the GM complex to phosphorylated H2AX at DSBs. GRB2 K109 ubiquitination by E3 ubiquitin ligase RBBP6 releases MRE11 promoting HDR. RBBP6 depletion results in prolonged GM complex and HDR defects. GRB2 knockout increased MRE11-XRCC1 complex and Alt-EJ. Reconstitution with separation-of-function GRB2 mutant caused HDR deficiency and synthetic lethality with PARP inhibitor. Cell and cancer genome analyses suggest biomarkers of low GRB2 for noncanonical HDR deficiency and high MRE11 and GRB2 expression for worse survival in HDR-proficient patients. These findings establish GRB2's role in binding, targeting, and releasing MRE11 to promote efficient HDR over Alt-EJ DSB repair, with implications for genome stability and cancer biology.
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Affiliation(s)
- Zu Ye
- Departments of Molecular and Cellular Oncology and Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Shengfeng Xu
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Yin Shi
- Department of Biochemistry, Zhejiang University School of Medicine, Hangzhou 310058, China
- Division of Pediatrics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Albino Bacolla
- Departments of Molecular and Cellular Oncology and Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Aleem Syed
- Departments of Molecular and Cellular Oncology and Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Davide Moiani
- Departments of Molecular and Cellular Oncology and Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Chi-Lin Tsai
- Departments of Molecular and Cellular Oncology and Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Qiang Shen
- Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
| | - Guang Peng
- Department of Clinical Cancer Prevention, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Paul G Leonard
- Institute for Applied Cancer Science, The University of Texas MD Anderson Cancer Center, 1881 East Road, Houston, TX 77054, USA
| | - Darin E Jones
- Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, 4301 West Markham Street, Little Rock, AR 72205, USA
| | - Bin Wang
- Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - John A Tainer
- Departments of Molecular and Cellular Oncology and Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
| | - Zamal Ahmed
- Departments of Molecular and Cellular Oncology and Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
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12
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Kim K, Kirby TW, Perera L, London RE. Phosphopeptide interactions of the Nbs1 N-terminal FHA-BRCT1/2 domains. Sci Rep 2021; 11:9046. [PMID: 33907233 PMCID: PMC8079451 DOI: 10.1038/s41598-021-88400-7] [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: 12/16/2020] [Accepted: 04/05/2021] [Indexed: 11/21/2022] Open
Abstract
Human Nbs1, a component of the MRN complex involved in DNA double strand break repair, contains a concatenated N-terminal FHA-BRCT1/2 sequence that supports interaction with multiple phosphopeptide binding partners. MDC1 binding localizes Nbs1 to the damage site, while binding of CDK-phosphorylated CtIP activates additional ATM-dependent CtIP phosphorylation, modulating substrate-dependent resection. We have investigated the phosphopeptide binding characteristics of Nbs1 BRCT1/2 based on a molecular modeling approach that revealed structural homology with the tandem TopBP1 BRCT7/8 domains. Relevance of the model was substantiated by the ability of TopBP1-binding FANCJ phosphopeptide to interact with hsNbsBRCT1/2, albeit with lower affinity. The modeled BRCT1/2 is characterized by low pSer/pThr selectivity, preference for a cationic residue at the + 2 position, and an inter-domain binding cleft selective for hydrophobic residues at the + 3/ + 4 positions. These features provide insight into the basis for interaction of SDT motifs with the BRCT1/2 domains and allowed identification of CtIP pSer347- and pThr847-containing phosphopeptides as high and lower affinity ligands, respectively. Among other binding partners considered, rodent XRCC1 contains an SDT sequence in the second linker consistent with high-affinity Nbs1 binding, while human XRCC1 lacks this motif, but contains other phosphorylated sequences that exhibit low-affinity binding.
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Affiliation(s)
- Kyungmin Kim
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC, 27709, USA
| | - Thomas W Kirby
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC, 27709, USA
| | - Lalith Perera
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC, 27709, USA
| | - Robert E London
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC, 27709, USA.
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13
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Rahman S, Beikzadeh M, Latham MP. Biochemical and structural characterization of analogs of MRE11 breast cancer-associated mutant F237C. Sci Rep 2021; 11:7089. [PMID: 33782469 PMCID: PMC8007570 DOI: 10.1038/s41598-021-86552-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 03/17/2021] [Indexed: 12/25/2022] Open
Abstract
The MRE11-RAD50-NBS1 (MRN) protein complex plays a vital role in DNA double strand break sensing, signaling, and repair. Mutation in any component of this complex may lead to disease as disrupting DNA double strand break repair has the potential to cause translocations and loss of genomic information. Here, we have investigated an MRE11 mutation, F237C, identified in a breast cancer tumor. We found that the analogous mutant of Pyrococcus furiosus Mre11 diminishes both the exonuclease and endonuclease activities of Mre11 in vitro. Solution state NMR experiments show that this mutant causes structural changes in the DNA-bound Mre11 for both exo- and endonuclease substrates and causes the protein to become generally more rigid. Moreover, by comparing the NMR data for this cancer-associated mutant with two previously described Mre11 separation-of-nuclease function mutants, a potential allosteric network was detected within Mre11 that connects the active site to regions responsible for recognizing the DNA ends and for dimerization. Together, our data further highlight the dynamics required for Mre11 nuclease function and illuminate the presence of allostery within the enzyme.
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Affiliation(s)
- Samiur Rahman
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, 79409-1061, USA
| | - Mahtab Beikzadeh
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, 79409-1061, USA
| | - Michael P Latham
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, 79409-1061, USA.
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14
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Panigrahi R, Glover JNM. Structural insights into DNA double-strand break signaling. Biochem J 2021; 478:135-156. [PMID: 33439989 DOI: 10.1042/bcj20200066] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 12/10/2020] [Accepted: 12/15/2020] [Indexed: 12/14/2022]
Abstract
Genomic integrity is most threatened by double-strand breaks, which, if left unrepaired, lead to carcinogenesis or cell death. The cell generates a network of protein-protein signaling interactions that emanate from the DNA damage which are now recognized as a rich basis for anti-cancer therapy development. Deciphering the structures of signaling proteins has been an uphill task owing to their large size and complex domain organization. Recent advances in mammalian protein expression/purification and cryo-EM-based structure determination have led to significant progress in our understanding of these large multidomain proteins. This review is an overview of the structural principles that underlie some of the key signaling proteins that function at the double-strand break site. We also discuss some plausible ideas that could be considered for future structural approaches to visualize and build a more complete understanding of protein dynamics at the break site.
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Affiliation(s)
- Rashmi Panigrahi
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - J N Mark Glover
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
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15
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McPherson MT, Holub AS, Husbands AY, Petreaca RC. Mutation Spectra of the MRN (MRE11, RAD50, NBS1/NBN) Break Sensor in Cancer Cells. Cancers (Basel) 2020; 12:cancers12123794. [PMID: 33339169 PMCID: PMC7765586 DOI: 10.3390/cancers12123794] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 12/04/2020] [Accepted: 12/14/2020] [Indexed: 12/12/2022] Open
Abstract
Simple Summary A DNA double strand break cuts a chromosome in two and is one of the most dangerous forms of DNA damage. Improper repair can lead to various chromosomal re-arrangements that have been detected in almost all cancer cells. A complex of three proteins (MRE11, RAD50, NBS1 or NBN) detects chromosome breaks and orchestrates repair processes. Mutations in these “break sensor” genes have been described in a multitude of cancers. Here, we provide a comprehensive analysis of reported mutations from data deposited on the Catalogue of Somatic Mutations in Cancer (COSMIC) archive. We also undertake an evolutionary analysis of these genes with the aim to understand whether these mutations preferentially accumulate in conserved residues. Interestingly, we find that mutations are overrepresented in evolutionarily conserved residues of RAD50 and NBS1/NBN but not MRE11. Abstract The MRN complex (MRE11, RAD50, NBS1/NBN) is a DNA double strand break sensor in eukaryotes. The complex directly participates in, or coordinates, several activities at the break such as DNA resection, activation of the DNA damage checkpoint, chromatin remodeling and recruitment of the repair machinery. Mutations in components of the MRN complex have been described in cancer cells for several decades. Using the Catalogue of Somatic Mutations in Cancer (COSMIC) database, we characterized all the reported MRN mutations. This analysis revealed several hotspot frameshift mutations in all three genes that introduce premature stop codons and truncate large regions of the C-termini. We also found through evolutionary analyses that COSMIC mutations are enriched in conserved residues of NBS1/NBN and RAD50 but not in MRE11. Given that all three genes are important to carcinogenesis, we propose these differential enrichment patterns may reflect a more severe pleiotropic role for MRE11.
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16
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Beikzadeh M, Latham MP. The dynamic nature of the Mre11-Rad50 DNA break repair complex. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2020; 163:14-22. [PMID: 33121960 DOI: 10.1016/j.pbiomolbio.2020.10.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 10/02/2020] [Accepted: 10/23/2020] [Indexed: 01/18/2023]
Abstract
The Mre11-Rad50-Nbs1/Xrs2 protein complex plays a pivotal role in the detection and repair of DNA double strand breaks. Through traditional and emerging structural biology techniques, various functional structural states of this complex have been visualized; however, relatively little is known about the transitions between these states. Indeed, it is these structural transitions that are important for Mre11-Rad50-mediated DNA unwinding at a break and the activation of downstream repair signaling events. Here, we present a brief overview of the current understanding of the structure of the core Mre11-Rad50 complex. We then highlight our recent studies emphasizing the contributions of solution state NMR spectroscopy and other biophysical techniques in providing insight into the structures and dynamics associated with Mre11-Rad50 functions.
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Affiliation(s)
- Mahtab Beikzadeh
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, USA
| | - Michael P Latham
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, USA.
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17
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A Survey of Reported Disease-Related Mutations in the MRE11-RAD50-NBS1 Complex. Cells 2020; 9:cells9071678. [PMID: 32668560 PMCID: PMC7407228 DOI: 10.3390/cells9071678] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 07/01/2020] [Accepted: 07/06/2020] [Indexed: 12/24/2022] Open
Abstract
The MRE11-RAD50-NBS1 (MRN) protein complex is one of the primary vehicles for repairing DNA double strand breaks and maintaining the genomic stability within the cell. The role of the MRN complex to recognize and process DNA double-strand breaks as well as signal other damage response factors is critical for maintaining proper cellular function. Mutations in any one of the components of the MRN complex that effect function or expression of the repair machinery could be detrimental to the cell and may initiate and/or propagate disease. Here, we discuss, in a structural and biochemical context, mutations in each of the three MRN components that have been associated with diseases such as ataxia telangiectasia-like disorder (ATLD), Nijmegen breakage syndrome (NBS), NBS-like disorder (NBSLD) and certain types of cancers. Overall, deepening our understanding of disease-causing mutations of the MRN complex at the structural and biochemical level is foundational to the future aim of treating diseases associated with these aberrations.
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18
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Yu TY, Garcia VE, Symington LS. CDK and Mec1/Tel1-catalyzed phosphorylation of Sae2 regulate different responses to DNA damage. Nucleic Acids Res 2020; 47:11238-11249. [PMID: 31552432 PMCID: PMC6868371 DOI: 10.1093/nar/gkz814] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 09/09/2019] [Accepted: 09/20/2019] [Indexed: 11/14/2022] Open
Abstract
Sae2 functions in the DNA damage response by controlling Mre11-Rad50-Xrs2 (MRX)-catalyzed end resection, an essential step for homology-dependent repair of double-strand breaks (DSBs), and by attenuating DNA damage checkpoint signaling. Phosphorylation of Sae2 by cyclin-dependent kinase (CDK1/Cdc28) activates the Mre11 endonuclease, while the physiological role of Sae2 phosphorylation by Mec1 and Tel1 checkpoint kinases is not fully understood. Here, we compare the phenotype of sae2 mutants lacking the main CDK (sae2-S267A) or Mec1 and Tel1 phosphorylation sites (sae2-5A) with sae2Δ and Mre11 nuclease defective (mre11-nd) mutants. The phosphorylation-site mutations confer DNA damage sensitivity, but not to the same extent as sae2Δ. The sae2-S267A mutation is epistatic to mre11-nd for camptothecin (CPT) sensitivity and synergizes with sgs1Δ, whereas sae2-5A synergizes with mre11-nd and exhibits epistasis with sgs1Δ. We find that attenuation of checkpoint signaling by Sae2 is mostly independent of Mre11 endonuclease activation but requires Mec1 and Tel1-dependent phosphorylation of Sae2. These results support a model whereby CDK-catalyzed phosphorylation of Sae2 activates resection via Mre11 endonuclease, whereas Sae2 phosphorylation by Mec1 and Tel1 promotes resection by the Dna2-Sgs1 and Exo1 pathways indirectly by dampening the DNA damage response.
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Affiliation(s)
- Tai-Yuan Yu
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Valerie E Garcia
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Lorraine S Symington
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY 10032, USA.,Department of Genetics & Development, Columbia University Irving Medical Center, New York, NY 10032, USA
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19
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Tisi R, Vertemara J, Zampella G, Longhese MP. Functional and structural insights into the MRX/MRN complex, a key player in recognition and repair of DNA double-strand breaks. Comput Struct Biotechnol J 2020; 18:1137-1152. [PMID: 32489527 PMCID: PMC7260605 DOI: 10.1016/j.csbj.2020.05.013] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Revised: 05/07/2020] [Accepted: 05/09/2020] [Indexed: 01/20/2023] Open
Abstract
Chromosomal DNA double-strand breaks (DSBs) are potentially lethal DNA lesions that pose a significant threat to genome stability and therefore need to be repaired to preserve genome integrity. Eukaryotic cells possess two main mechanisms for repairing DSBs: non-homologous end-joining (NHEJ) and homologous recombination (HR). HR requires that the 5' terminated strands at both DNA ends are nucleolytically degraded by a concerted action of nucleases in a process termed DNA-end resection. This degradation leads to the formation of 3'-ended single-stranded DNA (ssDNA) ends that are essential to use homologous DNA sequences for repair. The evolutionarily conserved Mre11-Rad50-Xrs2/NBS1 complex (MRX/MRN) has enzymatic and structural activities to initiate DSB resection and to maintain the DSB ends tethered to each other for their repair. Furthermore, it is required to recruit and activate the protein kinase Tel1/ATM, which plays a key role in DSB signaling. All these functions depend on ATP-regulated DNA binding and nucleolytic activities of the complex. Several structures have been obtained in recent years for Mre11 and Rad50 subunits from archaea, and a few from the bacterial and eukaryotic orthologs. Nevertheless, the mechanism of activation of this protein complex is yet to be fully elucidated. In this review, we focused on recent biophysical and structural insights on the MRX complex and their interplay.
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Affiliation(s)
- Renata Tisi
- Dipartimento di Biotecnologie and Bioscienze, Università degli Studi di Milano-Bicocca, Milan, Italy
| | - Jacopo Vertemara
- Dipartimento di Biotecnologie and Bioscienze, Università degli Studi di Milano-Bicocca, Milan, Italy
| | - Giuseppe Zampella
- Dipartimento di Biotecnologie and Bioscienze, Università degli Studi di Milano-Bicocca, Milan, Italy
| | - Maria Pia Longhese
- Dipartimento di Biotecnologie and Bioscienze, Università degli Studi di Milano-Bicocca, Milan, Italy
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20
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Nitrogen starvation reveals the mitotic potential of mutants in the S/MAPK pathways. Nat Commun 2020; 11:1973. [PMID: 32332728 PMCID: PMC7181643 DOI: 10.1038/s41467-020-15880-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 03/24/2020] [Indexed: 02/08/2023] Open
Abstract
The genetics of quiescence is an emerging field compared to that of growth, yet both states generate spontaneous mutations and genetic diversity fueling evolution. Reconciling mutation rates in dividing conditions and mutation accumulation as a function of time in non-dividing situations remains a challenge. Nitrogen-starved fission yeast cells reversibly arrest proliferation, are metabolically active and highly resistant to a variety of stresses. Here, we show that mutations in stress- and mitogen-activated protein kinase (S/MAPK) signaling pathways are enriched in aging cultures. Targeted resequencing and competition experiments indicate that these mutants arise in the first month of quiescence and expand clonally during the second month at the expense of the parental population. Reconstitution experiments show that S/MAPK modules mediate the sacrifice of many cells for the benefit of some mutants. These findings suggest that non-dividing conditions promote genetic diversity to generate a social cellular environment prone to kin selection. Nitrogen-starved fission yeast cells survive for weeks without dividing. Here, the authors show that some of these surviving cells accumulate mutations in the stress- and mitogen-activated protein kinase pathways and outcompete their parental cells, which provide nutrients for the mutant cells.
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21
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Mutation of Conserved Mre11 Residues Alter Protein Dynamics to Separate Nuclease Functions. J Mol Biol 2020; 432:3289-3308. [PMID: 32246962 DOI: 10.1016/j.jmb.2020.03.030] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 03/25/2020] [Accepted: 03/26/2020] [Indexed: 02/08/2023]
Abstract
Naked and protein-blocked DNA ends occur naturally during immune cell development, meiosis, and at telomeres as well as from aborted topoisomerase reactions, collapsed replication forks, and other stressors. Damaged DNA ends are dangerous in cells and if left unrepaired can lead to genomic rearrangement, loss of genetic information, and eventually cancer. Mre11 is part of the Mre11-Rad50-Nbs1 complex that recognizes DNA double-strand breaks and has exonuclease and endonuclease activities that help to initiate the repair processes to resolve these broken DNA ends. In fact, these activities are crucial for proper DNA damage repair pathway choice. Here, using Pyrococcus furiosus Mre11, we question how two Mre11 separation-of-function mutants, one previously described but the second first described here, maintain endonuclease activity in the absence of exonuclease activity. To start, we performed solution-state NMR experiments to assign the side-chain methyl groups of the 64-kDa Mre11 nuclease and capping domains, which allowed us to describe the structural differences between Mre11 bound to exo- and endonuclease substrates. Then, through biochemical and biophysical characterization, including NMR structural and dynamics studies, we compared the two mutants and determined that both affect the dynamic features and double-stranded DNA binding properties of Mre11, but in different ways. In total, our results illuminate the structural and dynamic landscape of Mre11 nuclease function.
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22
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Boswell ZK, Canny MD, Buschmann TA, Sang J, Latham MP. Adjacent mutations in the archaeal Rad50 ABC ATPase D-loop disrupt allosteric regulation of ATP hydrolysis through different mechanisms. Nucleic Acids Res 2020; 48:2457-2472. [PMID: 31889185 PMCID: PMC7049730 DOI: 10.1093/nar/gkz1228] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 11/25/2019] [Accepted: 12/20/2019] [Indexed: 11/29/2022] Open
Abstract
DNA damage is the driving force for mutation and genomic instability, which can both lead to cell death or carcinogenesis. DNA double strand breaks are detected and processed in part by the Mre11-Rad50-Nbs1 protein complex. Although the Mre11-Rad50-Nbs1 complex is essential, several spontaneous mutations have been noted in various cancers. One of these mutations, within a conserved motif of Rad50, resulted in an outlier curative response in a clinical trial. We show through biochemical and biophysical characterization that this cancer-associated mutation and a second mutation to the adjacent residue, previously described in a breast cancer patient, both have gain-of-function Rad50 ATP hydrolysis activity that results not from faster association of the ATP-bound form but faster dissociation leading to less stable Rad50 dimer. This disruption impairs the regulatory functions of the protein complex leading to a loss of exonuclease activity from Mre11. Interestingly, these two mutations affect Rad50 structure and dynamics quite differently. These studies describe the relationship between function, structure, and molecular motions in improperly regulated Rad50, which reveal the underlying biophysical mechanism for how these two cancer-associated mutations affect the cell.
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Affiliation(s)
- Zachary K Boswell
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409-1061, USA
| | - Marella D Canny
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409-1061, USA
| | - Tanner A Buschmann
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409-1061, USA
| | - Julie Sang
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409-1061, USA
| | - Michael P Latham
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409-1061, USA
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23
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NBS1 is required for SPO11-linked DNA double-strand break repair in male meiosis. Cell Death Differ 2020; 27:2176-2190. [PMID: 31965061 PMCID: PMC7308329 DOI: 10.1038/s41418-020-0493-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 01/01/2020] [Accepted: 01/09/2020] [Indexed: 01/21/2023] Open
Abstract
DNA double-strand breaks (DSBs) pose a serious threat to genomic stability. Paradoxically, hundreds of programed DSBs are generated by SPO11 in meiotic prophase, which are exclusively repaired by homologous recombination (HR) to promote obligate crossover between homologous chromosomes. In somatic cells, MRE11-RAD50-NBS1 (MRN) complex-dependent DNA end resection is a prerequisite for HR repair, especially for DSBs that are covalently linked with proteins or chemicals. Interestingly, all meiotic DSBs are linked with SPO11 after being generated. Although MRN complex’s function in meiotic DSB repair has been established in lower organisms, the role of MRN complex in mammalian meiotic DSB repair is not clear. Here, we show that MRN complex is essential for repairing meiotic SPO11-linked DSBs in male mice. In male germ cells, conditional inactivation of NBS1, a key component of MRN complex, causes dramatic reduction of DNA end resection and defective HR repair in meiotic prophase. NBS1 loss severely disrupts chromosome synapsis, generates abnormal chromosome structures, and eventually leads to meiotic arrest and male infertility in mice. Unlike in somatic cells, the recruitment of NBS1 to SPO11-linked DSB sites is MDC1-independent but requires other phosphorylated proteins. Collectively, our study not only reveals the significance of MRN complex in repairing meiotic DSBs but also discovers a unique mechanism that recruits MRN complex to SPO11-linked DSB sites.
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24
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Sun Y, McCorvie TJ, Yates LA, Zhang X. Structural basis of homologous recombination. Cell Mol Life Sci 2020; 77:3-18. [PMID: 31748913 PMCID: PMC6957567 DOI: 10.1007/s00018-019-03365-1] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 10/10/2019] [Accepted: 10/31/2019] [Indexed: 12/12/2022]
Abstract
Homologous recombination (HR) is a pathway to faithfully repair DNA double-strand breaks (DSBs). At the core of this pathway is a DNA recombinase, which, as a nucleoprotein filament on ssDNA, pairs with homologous DNA as a template to repair the damaged site. In eukaryotes Rad51 is the recombinase capable of carrying out essential steps including strand invasion, homology search on the sister chromatid and strand exchange. Importantly, a tightly regulated process involving many protein factors has evolved to ensure proper localisation of this DNA repair machinery and its correct timing within the cell cycle. Dysregulation of any of the proteins involved can result in unchecked DNA damage, leading to uncontrolled cell division and cancer. Indeed, many are tumour suppressors and are key targets in the development of new cancer therapies. Over the past 40 years, our structural and mechanistic understanding of homologous recombination has steadily increased with notable recent advancements due to the advances in single particle cryo electron microscopy. These have resulted in higher resolution structural models of the signalling proteins ATM (ataxia telangiectasia mutated), and ATR (ataxia telangiectasia and Rad3-related protein), along with various structures of Rad51. However, structural information of the other major players involved, such as BRCA1 (breast cancer type 1 susceptibility protein) and BRCA2 (breast cancer type 2 susceptibility protein), has been limited to crystal structures of isolated domains and low-resolution electron microscopy reconstructions of the full-length proteins. Here we summarise the current structural understanding of homologous recombination, focusing on key proteins in recruitment and signalling events as well as the mediators for the Rad51 recombinase.
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Affiliation(s)
- Yueru Sun
- Section of Structural Biology, Department of Infectious Diseases, Imperial College, London, SW7 2AZ, UK
| | - Thomas J McCorvie
- Section of Structural Biology, Department of Infectious Diseases, Imperial College, London, SW7 2AZ, UK
| | - Luke A Yates
- Section of Structural Biology, Department of Infectious Diseases, Imperial College, London, SW7 2AZ, UK
| | - Xiaodong Zhang
- Section of Structural Biology, Department of Infectious Diseases, Imperial College, London, SW7 2AZ, UK.
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25
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Fiévet A, Bellanger D, Zahed L, Burglen L, Derrien AC, Dubois d'Enghien C, Lespinasse J, Parfait B, Pedespan JM, Rieunier G, Stoppa-Lyonnet D, Stern MH. DNA repair functional analyses of NBN hypomorphic variants associated with NBN-related infertility. Hum Mutat 2019; 41:608-618. [PMID: 31729086 DOI: 10.1002/humu.23955] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Revised: 10/17/2019] [Accepted: 11/03/2019] [Indexed: 01/17/2023]
Abstract
Nijmegen breakage syndrome caused by biallelic pathogenic variants of the DNA-damage response gene NBN, is characterized by severe microcephaly, cancer proneness, infertility, and karyotype abnormalities. We previously reported NBN variants in siblings suffering from fertility defects. Here, we identify a new founder NBN variant (c.442A>G, p.(Thr148Ala)) in Lebanese patients associated with isolated infertility. Functional analyses explored preserved or altered functions correlated with their remarkably mild phenotype. Transcript and protein analyses supported the use of an alternative transcript with in-frame skipping of exons 4-5, leading to p84-NBN protein with a preserved forkhead-associated (FHA) domain. The level of NBN was dramatically reduced and the MRN complex delocalized to the cytoplasm. Interestingly, ataxia-elangiectasia mutated (ATM) also shifted from the nucleus to the cytoplasm, suggesting some interaction between ATM and the MRN complex at a steady state. The ATM pathway activation, attenuated in typical patients with NBS, appeared normal under camptothecin treatment in these new NBN-related infertile patients. Cell cycle checkpoint defect was present in these atypical patients, although to a lesser extent than in typical patients with NBS. In conclusion, we report three new NBN-related infertile patients and we suggest that preserved FHA domain could be responsible for the mild phenotype and intermediate DNA-damage response defects.
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Affiliation(s)
- Alice Fiévet
- INSERM U830, Institut Curie, PSL Research University, Paris, France.,D.R.U.M. Team, INSERM U830, Institut Curie, Paris, France.,Service de Génétique, Institut Curie Hôpital, Paris, France.,Service Génétique des Tumeurs, Gustave Roussy, Villejuif, France
| | - Dorine Bellanger
- INSERM U830, Institut Curie, PSL Research University, Paris, France.,D.R.U.M. Team, INSERM U830, Institut Curie, Paris, France
| | - Laila Zahed
- Department of Clinical Laboratory, Saint George Hospital University Medical Center, Beirut, Lebanon
| | - Lydie Burglen
- Centre de Référence des, Malformations et Maladies Congénitales du Cervelet, Paris, France.,GRC n°19, Pathologies Congénitales du Cervelet-LeucoDystrophies, Hôpital Armand Trousseau (APHP), Sorbonne Université, Paris, France.,INSERM U1141, Université Paris Diderot, Paris, France.,Département de Génétique Médicale (GHUEP), Hôpital Armand Trousseau (APHP), Paris, France
| | - Anne-Céline Derrien
- INSERM U830, Institut Curie, PSL Research University, Paris, France.,D.R.U.M. Team, INSERM U830, Institut Curie, Paris, France
| | | | - James Lespinasse
- Génétique Chromosomique, Centre Hospitalier Metropole Savoie, Chambéry-Hôtel-Dieu, Chambéry, France
| | - Béatrice Parfait
- Centre de ressources Biologiques, Hôpital Cochin, Assistance Publique - Hôpitaux de Paris, Paris, France
| | | | - Guillaume Rieunier
- INSERM U830, Institut Curie, PSL Research University, Paris, France.,D.R.U.M. Team, INSERM U830, Institut Curie, Paris, France
| | - Dominique Stoppa-Lyonnet
- D.R.U.M. Team, INSERM U830, Institut Curie, Paris, France.,Service de Génétique, Institut Curie Hôpital, Paris, France.,Université Paris Descartes, Sorbonne-Paris-Cité, Paris, France
| | - Marc-Henri Stern
- INSERM U830, Institut Curie, PSL Research University, Paris, France.,D.R.U.M. Team, INSERM U830, Institut Curie, Paris, France.,Service de Génétique, Institut Curie Hôpital, Paris, France
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26
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Deshpande I, Keusch JJ, Challa K, Iesmantavicius V, Gasser SM, Gut H. The Sir4 H-BRCT domain interacts with phospho-proteins to sequester and repress yeast heterochromatin. EMBO J 2019; 38:e101744. [PMID: 31515872 PMCID: PMC6792019 DOI: 10.15252/embj.2019101744] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 07/24/2019] [Accepted: 08/11/2019] [Indexed: 12/22/2022] Open
Abstract
In Saccharomyces cerevisiae, the silent information regulator (SIR) proteins Sir2/3/4 form a complex that suppresses transcription in subtelomeric regions and at the homothallic mating-type (HM) loci. Here, we identify a non-canonical BRCA1 C-terminal domain (H-BRCT) in Sir4, which is responsible for tethering telomeres to the nuclear periphery. We show that Sir4 H-BRCT and the closely related Dbf4 H-BRCT serve as selective phospho-epitope recognition domains that bind to a variety of phosphorylated target peptides. We present detailed structural information about the binding mode of established Sir4 interactors (Esc1, Ty5, Ubp10) and identify several novel interactors of Sir4 H-BRCT, including the E3 ubiquitin ligase Tom1. Based on these findings, we propose a phospho-peptide consensus motif for interaction with Sir4 H-BRCT and Dbf4 H-BRCT. Ablation of the Sir4 H-BRCT phospho-peptide interaction disrupts SIR-mediated repression and perinuclear localization. In conclusion, the Sir4 H-BRCT domain serves as a hub for recruitment of phosphorylated target proteins to heterochromatin to properly regulate silencing and nuclear order.
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Affiliation(s)
- Ishan Deshpande
- Friedrich Miescher Institute for Biomedical ResearchBaselSwitzerland
- Faculty of Natural SciencesUniversity of BaselBaselSwitzerland
- Present address:
Department of Pharmaceutical ChemistryUniversity of California San FranciscoSan FranciscoCAUSA
| | - Jeremy J Keusch
- Friedrich Miescher Institute for Biomedical ResearchBaselSwitzerland
| | - Kiran Challa
- Friedrich Miescher Institute for Biomedical ResearchBaselSwitzerland
| | | | - Susan M Gasser
- Friedrich Miescher Institute for Biomedical ResearchBaselSwitzerland
- Faculty of Natural SciencesUniversity of BaselBaselSwitzerland
| | - Heinz Gut
- Friedrich Miescher Institute for Biomedical ResearchBaselSwitzerland
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27
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Nbn-Mre11 interaction is required for tumor suppression and genomic integrity. Proc Natl Acad Sci U S A 2019; 116:15178-15183. [PMID: 31285322 DOI: 10.1073/pnas.1905305116] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
We derived a mouse model in which a mutant form of Nbn/Nbs1mid8 (hereafter Nbnmid8) exhibits severely impaired binding to the Mre11-Rad50 core of the Mre11 complex. The Nbn mid8 allele was expressed exclusively in hematopoietic lineages (in Nbn -/mid8vav mice). Unlike Nbn flox/floxvav mice with Nbn deficiency in the bone marrow, Nbn -/mid8vav mice were viable. Nbn -/mid8vav mice hematopoiesis was profoundly defective, exhibiting reduced cellularity of thymus and bone marrow, and stage-specific blockage of B cell development. Within 6 mo, Nbn -/mid8 mice developed highly penetrant T cell leukemias. Nbn -/mid8vav leukemias recapitulated mutational features of human T cell acute lymphoblastic leukemia (T-ALL), containing mutations in NOTCH1, TP53, BCL6, BCOR, and IKZF1, suggesting that Nbn mid8 mice may provide a venue to examine the relationship between the Mre11 complex and oncogene activation in the hematopoietic compartment. Genomic analysis of Nbn -/mid8vav malignancies showed focal amplification of 9qA2, causing overexpression of MRE11 and CHK1 We propose that overexpression of MRE11 compensates for the metastable Mre11-Nbnmid8 interaction, and that selective pressure for overexpression reflects the essential role of Nbn in promoting assembly and activity of the Mre11 complex.
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28
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Leimbacher PA, Jones SE, Shorrocks AMK, de Marco Zompit M, Day M, Blaauwendraad J, Bundschuh D, Bonham S, Fischer R, Fink D, Kessler BM, Oliver AW, Pearl LH, Blackford AN, Stucki M. MDC1 Interacts with TOPBP1 to Maintain Chromosomal Stability during Mitosis. Mol Cell 2019; 74:571-583.e8. [PMID: 30898438 PMCID: PMC6509287 DOI: 10.1016/j.molcel.2019.02.014] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 12/30/2018] [Accepted: 02/11/2019] [Indexed: 12/29/2022]
Abstract
In mitosis, cells inactivate DNA double-strand break (DSB) repair pathways to preserve genome stability. However, some early signaling events still occur, such as recruitment of the scaffold protein MDC1 to phosphorylated histone H2AX at DSBs. Yet, it remains unclear whether these events are important for maintaining genome stability during mitosis. Here, we identify a highly conserved protein-interaction surface in MDC1 that is phosphorylated by CK2 and recognized by the DNA-damage response mediator protein TOPBP1. Disruption of MDC1-TOPBP1 binding causes a specific loss of TOPBP1 recruitment to DSBs in mitotic but not interphase cells, accompanied by mitotic radiosensitivity, increased micronuclei, and chromosomal instability. Mechanistically, we find that TOPBP1 forms filamentous structures capable of bridging MDC1 foci in mitosis, indicating that MDC1-TOPBP1 complexes tether DSBs until repair is reactivated in the following G1 phase. Thus, we reveal an important, hitherto-unnoticed cooperation between MDC1 and TOPBP1 in maintaining genome stability during cell division.
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Affiliation(s)
- Pia-Amata Leimbacher
- Department of Gynecology, University Hospital and University of Zurich, Wagistrasse 14, 8952 Schlieren, Switzerland
| | - Samuel E Jones
- Department of Oncology, Medical Research Council Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK; Cancer Research UK/Medical Research Council Oxford Institute for Radiation Oncology, University of Oxford, Oxford OX3 7DQ, UK
| | - Ann-Marie K Shorrocks
- Department of Oncology, Medical Research Council Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK; Cancer Research UK/Medical Research Council Oxford Institute for Radiation Oncology, University of Oxford, Oxford OX3 7DQ, UK
| | - Mara de Marco Zompit
- Department of Gynecology, University Hospital and University of Zurich, Wagistrasse 14, 8952 Schlieren, Switzerland
| | - Matthew Day
- Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer BN1 9RQ, UK
| | - Jordy Blaauwendraad
- Department of Gynecology, University Hospital and University of Zurich, Wagistrasse 14, 8952 Schlieren, Switzerland
| | - Diana Bundschuh
- Department of Gynecology, University Hospital and University of Zurich, Wagistrasse 14, 8952 Schlieren, Switzerland
| | - Sarah Bonham
- Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7FZ, UK
| | - Roman Fischer
- Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7FZ, UK
| | - Daniel Fink
- Department of Gynecology, University Hospital and University of Zurich, Wagistrasse 14, 8952 Schlieren, Switzerland
| | - Benedikt M Kessler
- Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7FZ, UK
| | - Antony W Oliver
- Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer BN1 9RQ, UK
| | - Laurence H Pearl
- Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer BN1 9RQ, UK
| | - Andrew N Blackford
- Department of Oncology, Medical Research Council Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK; Cancer Research UK/Medical Research Council Oxford Institute for Radiation Oncology, University of Oxford, Oxford OX3 7DQ, UK.
| | - Manuel Stucki
- Department of Gynecology, University Hospital and University of Zurich, Wagistrasse 14, 8952 Schlieren, Switzerland.
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29
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Anand R, Jasrotia A, Bundschuh D, Howard SM, Ranjha L, Stucki M, Cejka P. NBS1 promotes the endonuclease activity of the MRE11-RAD50 complex by sensing CtIP phosphorylation. EMBO J 2019; 38:e101005. [PMID: 30787182 PMCID: PMC6443204 DOI: 10.15252/embj.2018101005] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 01/08/2019] [Accepted: 02/01/2019] [Indexed: 11/09/2022] Open
Abstract
DNA end resection initiates DNA double-strand break repair by homologous recombination. MRE11-RAD50-NBS1 and phosphorylated CtIP perform the first resection step via MRE11-catalyzed endonucleolytic DNA cleavage. Human NBS1, more than its homologue Xrs2 in Saccharomyces cerevisiae, is crucial for this process, highlighting complex mechanisms that regulate the MRE11 nuclease in higher eukaryotes. Using a reconstituted system, we show here that NBS1, through its FHA and BRCT domains, functions as a sensor of CtIP phosphorylation. NBS1 then activates the MRE11-RAD50 nuclease through direct physical interactions with MRE11. In the absence of NBS1, MRE11-RAD50 exhibits a weaker nuclease activity, which requires CtIP but not strictly its phosphorylation. This identifies at least two mechanisms by which CtIP augments MRE11: a phosphorylation-dependent mode through NBS1 and a phosphorylation-independent mode without NBS1. In support, we show that limited DNA end resection occurs in vivo in the absence of the FHA and BRCT domains of NBS1. Collectively, our data suggest that NBS1 restricts the MRE11-RAD50 nuclease to S-G2 phase when CtIP is extensively phosphorylated. This defines mechanisms that regulate the MRE11 nuclease in DNA metabolism.
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Affiliation(s)
- Roopesh Anand
- Institute for Research in Biomedicine, Faculty of Biomedical Sciences, Università della Svizzera italiana (USI), Bellinzona, Switzerland
| | - Arti Jasrotia
- Department of Gynecology, University of Zurich, Schlieren, Switzerland
| | - Diana Bundschuh
- Department of Gynecology, University of Zurich, Schlieren, Switzerland
| | - Sean Michael Howard
- Institute for Research in Biomedicine, Faculty of Biomedical Sciences, Università della Svizzera italiana (USI), Bellinzona, Switzerland
| | - Lepakshi Ranjha
- Institute for Research in Biomedicine, Faculty of Biomedical Sciences, Università della Svizzera italiana (USI), Bellinzona, Switzerland
| | - Manuel Stucki
- Department of Gynecology, University of Zurich, Schlieren, Switzerland
| | - Petr Cejka
- Institute for Research in Biomedicine, Faculty of Biomedical Sciences, Università della Svizzera italiana (USI), Bellinzona, Switzerland
- Department of Biology, Institute of Biochemistry, Eidgenössische Technische Hochschule (ETH), Zürich, Switzerland
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30
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Oh J, Symington LS. Role of the Mre11 Complex in Preserving Genome Integrity. Genes (Basel) 2018; 9:E589. [PMID: 30501098 PMCID: PMC6315862 DOI: 10.3390/genes9120589] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 11/26/2018] [Accepted: 11/27/2018] [Indexed: 12/12/2022] Open
Abstract
DNA double-strand breaks (DSBs) are hazardous lesions that threaten genome integrity and cell survival. The DNA damage response (DDR) safeguards the genome by sensing DSBs, halting cell cycle progression and promoting repair through either non-homologous end joining (NHEJ) or homologous recombination (HR). The Mre11-Rad50-Xrs2/Nbs1 (MRX/N) complex is central to the DDR through its structural, enzymatic, and signaling roles. The complex tethers DNA ends, activates the Tel1/ATM kinase, resolves protein-bound or hairpin-capped DNA ends, and maintains telomere homeostasis. In addition to its role at DSBs, MRX/N associates with unperturbed replication forks, as well as stalled replication forks, to ensure complete DNA synthesis and to prevent chromosome rearrangements. Here, we summarize the significant progress made in characterizing the MRX/N complex and its various activities in chromosome metabolism.
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Affiliation(s)
- Julyun Oh
- Biological Sciences Program, Columbia University, New York, NY 10027, USA.
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY 10032, USA.
| | - Lorraine S Symington
- Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY 10032, USA.
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31
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Oh J, Lee SJ, Rothstein R, Symington LS. Xrs2 and Tel1 Independently Contribute to MR-Mediated DNA Tethering and Replisome Stability. Cell Rep 2018; 25:1681-1692.e4. [PMID: 30428339 PMCID: PMC6317890 DOI: 10.1016/j.celrep.2018.10.030] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 09/08/2018] [Accepted: 10/05/2018] [Indexed: 02/04/2023] Open
Abstract
The yeast Mre11-Rad50-Xrs2 (MRX) complex has structural, signaling, and catalytic functions in the response to DNA damage. Xrs2, the eukaryotic-specific component of the complex, is required for nuclear import of Mre11 and Rad50 and to recruit the Tel1 kinase to damage sites. We show that nuclear-localized MR complex (Mre11-NLS) catalyzes homology-dependent repair without Xrs2, but MR cannot activate Tel1, and it fails to tether DSBs, resulting in sensitivity to genotoxins, replisome instability, and increased gross chromosome rearrangements (GCRs). Fusing the Tel1 interaction domain from Xrs2 to Mre11-NLS is sufficient to restore telomere elongation and Tel1 signaling to Xrs2-deficient cells. Furthermore, Tel1 stabilizes Mre11-DNA association, and this stabilization function becomes important for DNA damage resistance in the absence of Xrs2. Enforcing Tel1 recruitment to the nuclear MR complex fully rescues end tethering and stalled replication fork stability, and suppresses GCRs, highlighting important roles for Xrs2 and Tel1 to ensure optimal MR activity.
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Affiliation(s)
- Julyun Oh
- Biological Sciences Program, Columbia University, New York, NY 10027, USA; Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - So Jung Lee
- Department of Genetics & Development, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Rodney Rothstein
- Biological Sciences Program, Columbia University, New York, NY 10027, USA; Department of Genetics & Development, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Lorraine S Symington
- Biological Sciences Program, Columbia University, New York, NY 10027, USA; Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY 10032, USA; Department of Genetics & Development, Columbia University Irving Medical Center, New York, NY 10032, USA.
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32
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Billing D, Horiguchi M, Wu-Baer F, Taglialatela A, Leuzzi G, Nanez SA, Jiang W, Zha S, Szabolcs M, Lin CS, Ciccia A, Baer R. The BRCT Domains of the BRCA1 and BARD1 Tumor Suppressors Differentially Regulate Homology-Directed Repair and Stalled Fork Protection. Mol Cell 2018; 72:127-139.e8. [PMID: 30244837 DOI: 10.1016/j.molcel.2018.08.016] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 06/23/2018] [Accepted: 08/07/2018] [Indexed: 10/28/2022]
Abstract
The BRCA1 tumor suppressor preserves genome integrity through both homology-directed repair (HDR) and stalled fork protection (SFP). In vivo, BRCA1 exists as a heterodimer with the BARD1 tumor suppressor, and both proteins harbor a phosphate-binding BRCT domain. Here, we compare mice with mutations that ablate BRCT phospho-recognition by Bard1 (Bard1S563F and Bard1K607A) or Brca1 (Brca1S1598F). Brca1S1598F abrogates both HDR and SFP, suggesting that both pathways are likely impaired in most BRCA1 mutant tumors. Although not affecting HDR, the Bard1 mutations ablate poly(ADP-ribose)-dependent recruitment of BRCA1/BARD1 to stalled replication forks, resulting in fork degradation and chromosome instability. Nonetheless, Bard1S563F/S563F and Bard1K607A/K607A mice, unlike Brca1S1598F/S1598F mice, are not tumor prone, indicating that HDR alone is sufficient to suppress tumor formation in the absence of SFP. Nevertheless, because SFP, unlike HDR, is also impaired in heterozygous Brca1/Bard1 mutant cells, SFP and HDR may contribute to distinct stages of tumorigenesis in BRCA1/BARD1 mutation carriers.
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Affiliation(s)
- David Billing
- Institute for Cancer Genetics, Columbia University Irving Medical Center, New York, NY 10032, USA; Department of Pathology & Cell Biology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Michiko Horiguchi
- Institute for Cancer Genetics, Columbia University Irving Medical Center, New York, NY 10032, USA; Department of Pathology & Cell Biology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Foon Wu-Baer
- Institute for Cancer Genetics, Columbia University Irving Medical Center, New York, NY 10032, USA; Department of Pathology & Cell Biology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Angelo Taglialatela
- Department of Genetics & Development, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Giuseppe Leuzzi
- Department of Genetics & Development, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Silvia Alvarez Nanez
- Department of Genetics & Development, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Wenxia Jiang
- Institute for Cancer Genetics, Columbia University Irving Medical Center, New York, NY 10032, USA; Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Shan Zha
- Institute for Cancer Genetics, Columbia University Irving Medical Center, New York, NY 10032, USA; Department of Pathology & Cell Biology, Columbia University Irving Medical Center, New York, NY 10032, USA; Department of Pediatrics, Columbia University Irving Medical Center, New York, NY 10032, USA; Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Matthias Szabolcs
- Department of Pathology & Cell Biology, Columbia University Irving Medical Center, New York, NY 10032, USA; Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Chyuan-Sheng Lin
- Department of Pathology & Cell Biology, Columbia University Irving Medical Center, New York, NY 10032, USA; Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Alberto Ciccia
- Department of Genetics & Development, Columbia University Irving Medical Center, New York, NY 10032, USA; Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Richard Baer
- Institute for Cancer Genetics, Columbia University Irving Medical Center, New York, NY 10032, USA; Department of Pathology & Cell Biology, Columbia University Irving Medical Center, New York, NY 10032, USA; Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY 10032, USA.
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33
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Phospho-dependent recruitment of the yeast NuA4 acetyltransferase complex by MRX at DNA breaks regulates RPA dynamics during resection. Proc Natl Acad Sci U S A 2018; 115:10028-10033. [PMID: 30224481 DOI: 10.1073/pnas.1806513115] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The KAT5 (Tip60/Esa1) histone acetyltransferase is part of NuA4, a large multifunctional complex highly conserved from yeast to mammals that targets lysines on H4 and H2A (X/Z) tails for acetylation. It is essential for cell viability, being a key regulator of gene expression, cell proliferation, and stem cell renewal and an important factor for genome stability. The NuA4 complex is directly recruited near DNA double-strand breaks (DSBs) to facilitate repair, in part through local chromatin modification and interplay with 53BP1 during the DNA damage response. While NuA4 is detected early after appearance of the lesion, its precise mechanism of recruitment remains to be defined. Here, we report a stepwise recruitment of yeast NuA4 to DSBs first by a DNA damage-induced phosphorylation-dependent interaction with the Xrs2 subunit of the Mre11-Rad50-Xrs2 (MRX) complex bound to DNA ends. This is followed by a DNA resection-dependent spreading of NuA4 on each side of the break along with the ssDNA-binding replication protein A (RPA). Finally, we show that NuA4 can acetylate RPA and regulate the dynamics of its binding to DNA, hence targeting locally both histone and nonhistone proteins for lysine acetylation to coordinate repair.
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34
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Su D, Ma S, Shan L, Wang Y, Wang Y, Cao C, Liu B, Yang C, Wang L, Tian S, Ding X, Liu X, Yu N, Song N, Liu L, Yang S, Zhang Q, Yang F, Zhang K, Shi L. Ubiquitin-specific protease 7 sustains DNA damage response and promotes cervical carcinogenesis. J Clin Invest 2018; 128:4280-4296. [PMID: 30179224 DOI: 10.1172/jci120518] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 07/24/2018] [Indexed: 12/24/2022] Open
Abstract
Central to the recognition, signaling, and repair of DNA double-strand breaks (DSBs) are the MRE11-RAD50-NBS1 (MRN) complex and mediator of DNA damage checkpoint protein 1 (MDC1), the interplay of which is essential for initiation and amplification of the DNA damage response (DDR). The intrinsic rule governing the regulation of the function of this molecular machinery remains to be investigated. We report here that the ubiquitin-specific protease USP7 was physically associated with the MRN-MDC1 complex and that the MRN-MDC1 complex acted as a platform for USP7 to efficiently deubiquitinate and stabilize MDC1, thereby sustaining the DDR. Accordingly, depletion of USP7 impaired the engagement of the MRN-MDC1 complex and the consequent recruitment of the downstream factors p53-binding protein 1 (53BP1) and breast cancer protein 1 (BRCA1) at DNA lesions. Significantly, USP7 was overexpressed in cervical cancer, and the level of its expression positively correlated with that of MDC1 and worse survival rates for patients with cervical cancer. We demonstrate that USP7-mediated MDC1 stabilization promoted cervical cancer cell survival and conferred cellular resistance to genotoxic insults. Together, our study reveals a role for USP7 in regulating the function of the MRN-MDC1 complex and activity of the DDR, supporting the pursuit of USP7 as a potential therapeutic target for MDC1-proficient cancers.
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Affiliation(s)
- Dongxue Su
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Shuai Ma
- 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, Tianjin Key Laboratory of Medical Epigenetics, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University, Tianjin, China
| | - Lin Shan
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Yue Wang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Yuejiao Wang
- 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, Tianjin Key Laboratory of Medical Epigenetics, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University, Tianjin, China
| | - Cheng Cao
- 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, Tianjin Key Laboratory of Medical Epigenetics, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University, Tianjin, China
| | - Beibei Liu
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Chao Yang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Liyong Wang
- Core Facilities for Molecular Biology, Capital Medical University, Beijing, China
| | - Shanshan Tian
- 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, Tianjin Key Laboratory of Medical Epigenetics, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University, Tianjin, China
| | - Xiang Ding
- Laboratory of Proteomics, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Xinhua Liu
- 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, Tianjin Key Laboratory of Medical Epigenetics, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University, Tianjin, China
| | - Na Yu
- 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, Tianjin Key Laboratory of Medical Epigenetics, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University, Tianjin, China
| | - Nan Song
- 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, Tianjin Key Laboratory of Medical Epigenetics, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University, Tianjin, China
| | - Ling Liu
- 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, Tianjin Key Laboratory of Medical Epigenetics, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University, Tianjin, China
| | - Shangda Yang
- 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, Tianjin Key Laboratory of Medical Epigenetics, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University, Tianjin, China
| | - Qi Zhang
- 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, Tianjin Key Laboratory of Medical Epigenetics, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University, Tianjin, China
| | - Fuquan Yang
- Laboratory of Proteomics, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Kai Zhang
- 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, Tianjin Key Laboratory of Medical Epigenetics, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University, Tianjin, China
| | - Lei Shi
- 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, Tianjin Key Laboratory of Medical Epigenetics, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University, Tianjin, China
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35
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Lin ZP, Zhu YL, Ratner ES. Targeting Cyclin-Dependent Kinases for Treatment of Gynecologic Cancers. Front Oncol 2018; 8:303. [PMID: 30135856 PMCID: PMC6092490 DOI: 10.3389/fonc.2018.00303] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 07/19/2018] [Indexed: 02/01/2023] Open
Abstract
Ovarian, uterine/endometrial, and cervical cancers are major gynecologic malignancies estimated to cause nearly 30,000 deaths in 2018 in US. Defective cell cycle regulation is the hallmark of cancers underpinning the development and progression of the disease. Normal cell cycle is driven by the coordinated and sequential rise and fall of cyclin-dependent kinases (CDK) activity. The transition of cell cycle phases is governed by the respective checkpoints that prevent the entry into the next phase until cellular or genetic defects are repaired. Checkpoint activation is achieved by p53- and ATM/ATR-mediated inactivation of CDKs in response to DNA damage. Therefore, an aberrant increase in CDK activity and/or defects in checkpoint activation lead to unrestricted cell cycle phase transition and uncontrolled proliferation that give rise to cancers and perpetuate malignant progression. Given that CDK activity is also required for homologous recombination (HR) repair, pharmacological inhibition of CDKs can be exploited as a synthetic lethal approach to augment the therapeutic efficacy of PARP inhibitors and other DNA damaging modalities for the treatment of gynecologic cancers. Here, we overview the basic of cell cycle and discuss the mechanistic studies that establish the intimate link between CDKs and HR repair. In addition, we present the perspective of preclinical and clinical development in small molecule inhibitors of CDKs and CDK-associated protein targets, as well as their potential use in combination with hormonal therapy, PARP inhibitors, chemotherapy, and radiation to improve treatment outcomes.
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Affiliation(s)
- Z Ping Lin
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale University School of Medicine, New Haven, CT, United States
| | - Yong-Lian Zhu
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale University School of Medicine, New Haven, CT, United States
| | - Elena S Ratner
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale University School of Medicine, New Haven, CT, United States
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Paull TT. 20 Years of Mre11 Biology: No End in Sight. Mol Cell 2018; 71:419-427. [PMID: 30057197 DOI: 10.1016/j.molcel.2018.06.033] [Citation(s) in RCA: 95] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 05/18/2018] [Accepted: 06/21/2018] [Indexed: 01/01/2023]
Abstract
The Mre11 nuclease has been the subject of intensive investigation for the past 20 years because of the central role that Mre11/Rad50 complexes play in genome maintenance. The last two decades of work on this complex has led to a much deeper understanding of the structure, biochemical activities, and regulation of Mre11/Rad50 complexes from archaea, bacteria, and eukaryotic cells. This review will discuss some of the important findings over recent years that have illuminated roles for the Mre11 nuclease in these different contexts as well as the insights from structural biology that have helped us to understand its mechanisms of action.
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Affiliation(s)
- Tanya T Paull
- Howard Hughes Medical Institute; Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX 78712, USA.
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37
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Syed A, Tainer JA. The MRE11-RAD50-NBS1 Complex Conducts the Orchestration of Damage Signaling and Outcomes to Stress in DNA Replication and Repair. Annu Rev Biochem 2018; 87:263-294. [PMID: 29709199 PMCID: PMC6076887 DOI: 10.1146/annurev-biochem-062917-012415] [Citation(s) in RCA: 255] [Impact Index Per Article: 42.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Genomic instability in disease and its fidelity in health depend on the DNA damage response (DDR), regulated in part from the complex of meiotic recombination 11 homolog 1 (MRE11), ATP-binding cassette-ATPase (RAD50), and phosphopeptide-binding Nijmegen breakage syndrome protein 1 (NBS1). The MRE11-RAD50-NBS1 (MRN) complex forms a multifunctional DDR machine. Within its network assemblies, MRN is the core conductor for the initial and sustained responses to DNA double-strand breaks, stalled replication forks, dysfunctional telomeres, and viral DNA infection. MRN can interfere with cancer therapy and is an attractive target for precision medicine. Its conformations change the paradigm whereby kinases initiate damage sensing. Delineated results reveal kinase activation, posttranslational targeting, functional scaffolding, conformations storing binding energy and enabling access, interactions with hub proteins such as replication protein A (RPA), and distinct networks at DNA breaks and forks. MRN biochemistry provides prototypic insights into how it initiates, implements, and regulates multifunctional responses to genomic stress.
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Affiliation(s)
- Aleem Syed
- Department of Molecular and Cellular Oncology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030, USA; ,
| | - John A Tainer
- Department of Molecular and Cellular Oncology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030, USA; ,
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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Interdependent and separable functions of Caenorhabditis elegans MRN-C complex members couple formation and repair of meiotic DSBs. Proc Natl Acad Sci U S A 2018; 115:E4443-E4452. [PMID: 29686104 DOI: 10.1073/pnas.1719029115] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Faithful inheritance of genetic information through sexual reproduction relies on the formation of crossovers between homologous chromosomes during meiosis, which, in turn, relies on the formation and repair of numerous double-strand breaks (DSBs). As DSBs pose a potential threat to the genome, mechanisms that ensure timely and error-free DSB repair are crucial for successful meiosis. Here, we identify NBS-1, the Caenorhabditis elegans ortholog of the NBS1 (mutated in Nijmegen Breakage Syndrome) subunit of the conserved MRE11-RAD50-NBS1/Xrs2 (MRN) complex, as a key mediator of DSB repair via homologous recombination (HR) during meiosis. Loss of nbs-1 leads to severely reduced loading of recombinase RAD-51, ssDNA binding protein RPA, and pro-crossover factor COSA-1 during meiotic prophase progression; aggregated and fragmented chromosomes at the end of meiotic prophase; and 100% progeny lethality. These phenotypes reflect a role for NBS-1 in processing of meiotic DSBs for HR that is shared with its interacting partners MRE-11-RAD-50 and COM-1 (ortholog of Com1/Sae2/CtIP). Unexpectedly, in contrast to MRE-11 and RAD-50, NBS-1 is not required for meiotic DSB formation. Meiotic defects of the nbs-1 mutant are partially suppressed by abrogation of the nonhomologous end-joining (NHEJ) pathway, indicating a role for NBS-1 in antagonizing NHEJ during meiosis. Our data further reveal that NBS-1 and COM-1 play distinct roles in promoting HR and antagonizing NHEJ. We propose a model in which different components of the MRN-C complex work together to couple meiotic DSB formation with efficient and timely engagement of HR, thereby ensuring crossover formation and restoration of genome integrity before the meiotic divisions.
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Limbo O, Yamada Y, Russell P. Mre11-Rad50-dependent activity of ATM/Tel1 at DNA breaks and telomeres in the absence of Nbs1. Mol Biol Cell 2018; 29:1389-1399. [PMID: 29851556 PMCID: PMC5994899 DOI: 10.1091/mbc.e17-07-0470] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The Mre11-Rad50-Nbs1 (MRN) protein complex and ATM/Tel1 kinase protect genome integrity through their functions in DNA double-strand break (DSB) repair, checkpoint signaling, and telomere maintenance. Nbs1 has a conserved C-terminal motif that binds ATM/Tel1, but the full extent and significance of ATM/Tel1 interactions with MRN are unknown. Here, we show that Tel1 overexpression bypasses the requirement for Nbs1 in DNA damage signaling and telomere maintenance. These activities require Mre11-Rad50, which localizes to DSBs and bind Tel1 in the absence of Nbs1. Fusion of the Tel1-binding motif of Nbs1 to Mre11 is sufficient to restore Tel1 signaling in nbs1Δ cells. Tel1 overexpression does not restore Tel1 signaling in cells carrying the rad50-I1192W mutation, which impairs the ability of Mre11-Rad50 to form the ATP-bound closed conformation. From these findings, we propose that Tel1 has a high-affinity interaction with the C-terminus of Nbs1 and a low-affinity association with Mre11-Rad50, which together accomplish efficient localization and activation of Tel1 at DSBs and telomeres.
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Affiliation(s)
- Oliver Limbo
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037
| | - Yoshiki Yamada
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037
| | - Paul Russell
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037
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Kim JH, Grosbart M, Anand R, Wyman C, Cejka P, Petrini JHJ. The Mre11-Nbs1 Interface Is Essential for Viability and Tumor Suppression. Cell Rep 2017; 18:496-507. [PMID: 28076792 DOI: 10.1016/j.celrep.2016.12.035] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2016] [Revised: 11/04/2016] [Accepted: 12/12/2016] [Indexed: 02/02/2023] Open
Abstract
The Mre11 complex (Mre11, Rad50, and Nbs1) is integral to both DNA repair and ataxia telangiectasia mutated (ATM)-dependent DNA damage signaling. All three Mre11 complex components are essential for viability at the cellular and organismal levels. To delineate essential and non-essential Mre11 complex functions that are mediated by Nbs1, we used TALEN-based genome editing to derive Nbs1 mutant mice (Nbs1mid mice), which harbor mutations in the Mre11 interaction domain of Nbs1. Nbs1mid alleles that abolished interaction were incompatible with viability. Conversely, a 108-amino-acid Nbs1 fragment comprising the Mre11 interface was sufficient to rescue viability and ATM activation in cultured cells and support differentiation of hematopoietic cells in vivo. These data indicate that the essential role of Nbs1 is via its interaction with Mre11 and that most of the Nbs1 protein is dispensable for Mre11 complex functions and suggest that Mre11 and Rad50 directly activate ATM.
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Affiliation(s)
- Jun Hyun Kim
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10021, USA
| | - Malgorzata Grosbart
- Department of Molecular Genetics, Erasmus University Medical Center, 3000 Rotterdam, the Netherlands; Department of Radiation Oncology, Erasmus University Medical Center, 3000 Rotterdam, the Netherlands
| | - Roopesh Anand
- Institute for Research in Biomedicine, Università della Svizzera Italiana, Via Vincenzo Vela 6, 6500 Bellinzona, Switzerland
| | - Claire Wyman
- Department of Molecular Genetics, Erasmus University Medical Center, 3000 Rotterdam, the Netherlands; Department of Radiation Oncology, Erasmus University Medical Center, 3000 Rotterdam, the Netherlands
| | - Petr Cejka
- Institute for Research in Biomedicine, Università della Svizzera Italiana, Via Vincenzo Vela 6, 6500 Bellinzona, Switzerland
| | - John H J Petrini
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10021, USA.
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41
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Mlody B, Wruck W, Martins S, Sperling K, Adjaye J. Nijmegen Breakage Syndrome fibroblasts and iPSCs: cellular models for uncovering disease-associated signaling pathways and establishing a screening platform for anti-oxidants. Sci Rep 2017; 7:7516. [PMID: 28790359 PMCID: PMC5548734 DOI: 10.1038/s41598-017-07905-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 07/04/2017] [Indexed: 12/28/2022] Open
Abstract
Nijmegen Breakage Syndrome (NBS) is associated with cancer predisposition, premature aging, immune deficiency, microcephaly and is caused by mutations in the gene coding for NIBRIN (NBN) which is involved in DNA damage repair. Dermal-derived fibroblasts from NBS patients were reprogrammed into induced pluripotent stem cells (iPSCs) in order to bypass premature senescence. The influence of antioxidants on intracellular levels of ROS and DNA damage were screened and it was found that EDHB-an activator of the hypoxia pathway, decreased DNA damage in the presence of high oxidative stress. Furthermore, NBS fibroblasts but not NBS-iPSCs were found to be more susceptible to the induction of DNA damage than their healthy counterparts. Global transcriptome analysis comparing NBS to healthy fibroblasts and NBS-iPSCs to embryonic stem cells revealed regulation of P53 in NBS fibroblasts and NBS-iPSCs. Cell cycle related genes were down-regulated in NBS fibroblasts. Furthermore, oxidative phosphorylation was down-regulated and glycolysis up-regulated specifically in NBS-iPSCs compared to embryonic stem cells. Our study demonstrates the utility of NBS-iPSCs as a screening platform for anti-oxidants capable of suppressing DNA damage and a cellular model for studying NBN de-regulation in cancer and microcephaly.
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Affiliation(s)
- Barbara Mlody
- Max-Delbrück-Centrum für Molekulare Medizin (MDC), 13092, Berlin, Germany
| | - Wasco Wruck
- Institute for Stem Cell Research and Regenerative Medicine, Medical Faculty, Heinrich Heine University, 40225, Düsseldorf, Germany
| | - Soraia Martins
- Institute for Stem Cell Research and Regenerative Medicine, Medical Faculty, Heinrich Heine University, 40225, Düsseldorf, Germany
| | - Karl Sperling
- Charité - Universitätsmedizin Berlin, Institute of Medical and Human Genetics, 13353, Berlin, Germany
| | - James Adjaye
- Institute for Stem Cell Research and Regenerative Medicine, Medical Faculty, Heinrich Heine University, 40225, Düsseldorf, Germany.
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42
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Almawi AW, Matthews LA, Guarné A. FHA domains: Phosphopeptide binding and beyond. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017; 127:105-110. [DOI: 10.1016/j.pbiomolbio.2016.12.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2016] [Accepted: 12/06/2016] [Indexed: 01/18/2023]
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43
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Abstract
Vertebrate CtIP, and its fission yeast (Ctp1), budding yeast (Sae2) and plant (Com1) orthologs have emerged as key regulatory molecules in cellular responses to DNA double strand breaks (DSBs). By modulating the nucleolytic 5'-3' resection activity of the Mre11/Rad50/Nbs1 (MRN) DSB repair processing and signaling complex, CtIP/Ctp1/Sae2/Com1 is integral to the channeling of DNA double strand breaks through DSB repair by homologous recombination (HR). Nearly two decades since its discovery, emerging new data are defining the molecular underpinnings for CtIP DSB repair regulatory activities. CtIP homologs are largely intrinsically unstructured proteins comprised of expanded regions of low complexity sequence, rather than defined folded domains typical of DNA damage metabolizing enzymes and nucleases. A compact structurally conserved N-terminus forms a functionally critical tetrameric helical dimer of dimers (THDD) region that bridges CtIP oligomers, and is flexibly appended to a conserved C-terminal Sae2-homology DNA binding and DSB repair pathway choice regulatory hub which influences nucleolytic activities of the MRN core nuclease complex. The emerging evidence from structural, biophysical, and biological studies converges on CtIP having functional roles in DSB repair that include: 1) dynamic DNA strand coordination through direct DNA binding and DNA bridging activities, 2) MRN nuclease complex cofactor functions that direct MRN endonucleolytic cleavage of protein-blocked DSB ends and 3) acting as a protein binding hub targeted by the cell cycle regulatory apparatus, which influences CtIP expression and activity via layers of post-translational modifications, protein-protein interactions and DNA binding.
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Affiliation(s)
- Sara N Andres
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, US National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, United States
| | - R Scott Williams
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, US National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, United States.
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44
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Henrich SM, Usadel C, Werwein E, Burdova K, Janscak P, Ferrari S, Hess D, Klempnauer KH. Interplay with the Mre11-Rad50-Nbs1 complex and phosphorylation by GSK3β implicate human B-Myb in DNA-damage signaling. Sci Rep 2017; 7:41663. [PMID: 28128338 PMCID: PMC5269693 DOI: 10.1038/srep41663] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 12/21/2016] [Indexed: 12/30/2022] Open
Abstract
B-Myb, a highly conserved member of the Myb transcription factor family, is expressed ubiquitously in proliferating cells and controls the cell cycle dependent transcription of G2/M-phase genes. Deregulation of B-Myb has been implicated in oncogenesis and loss of genomic stability. We have identified B-Myb as a novel interaction partner of the Mre11-Rad50-Nbs1 (MRN) complex, a key player in the repair of DNA double strand breaks. We show that B-Myb directly interacts with the Nbs1 subunit of the MRN complex and is recruited transiently to DNA-damage sites. In response to DNA-damage B-Myb is phosphorylated by protein kinase GSK3β and released from the MRN complex. A B-Myb mutant that cannot be phosphorylated by GSK3β disturbs the regulation of pro-mitotic B-Myb target genes and leads to inappropriate mitotic entry in response to DNA-damage. Overall, our work suggests a novel function of B-Myb in the cellular DNA-damage signalling.
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Affiliation(s)
- Sarah Marie Henrich
- Institut for Biochemistry, Westfälische-Wilhelms-Universität, D-48149 Münster, Germany
- Graduate School of Chemistry (GSC-MS), Westfälische-Wilhelms-Universität, D-48149 Münster, Germany
| | - Clemens Usadel
- Institut for Biochemistry, Westfälische-Wilhelms-Universität, D-48149 Münster, Germany
| | - Eugen Werwein
- Institut for Biochemistry, Westfälische-Wilhelms-Universität, D-48149 Münster, Germany
| | - Kamila Burdova
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, 143 00 Prague, Czech Republic
| | - Pavel Janscak
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, 143 00 Prague, Czech Republic
- Institute of Molecular Cancer Research, University of Zurich, Winterthurerstr.190, CH-8057 Zürich, Switzerland
| | - Stefano Ferrari
- Institute of Molecular Cancer Research, University of Zurich, Winterthurerstr.190, CH-8057 Zürich, Switzerland
| | - Daniel Hess
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstr. 66, CH-4058 Basel, Switzerland
| | - Karl-Heinz Klempnauer
- Institut for Biochemistry, Westfälische-Wilhelms-Universität, D-48149 Münster, Germany
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45
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Xu X, Fan Z, Liang C, Li L, Wang L, Liang Y, Wu J, Chang S, Yan Z, Lv Z, Fu J, Liu Y, Jin S, Wang T, Hong T, Dong Y, Ding L, Cheng L, Liu R, Fu S, Jiao S, Ye Q. A signature motif in LIM proteins mediates binding to checkpoint proteins and increases tumour radiosensitivity. Nat Commun 2017; 8:14059. [PMID: 28094252 PMCID: PMC5247581 DOI: 10.1038/ncomms14059] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2016] [Accepted: 11/24/2016] [Indexed: 01/22/2023] Open
Abstract
Tumour radiotherapy resistance involves the cell cycle pathway. CDC25 phosphatases are key cell cycle regulators. However, how CDC25 activity is precisely controlled remains largely unknown. Here, we show that LIM domain-containing proteins, such as FHL1, increase inhibitory CDC25 phosphorylation by forming a complex with CHK2 and CDC25, and sequester CDC25 in the cytoplasm by forming another complex with 14-3-3 and CDC25, resulting in increased radioresistance in cancer cells. FHL1 expression, induced by ionizing irradiation in a SP1- and MLL1-dependent manner, positively correlates with radioresistance in cancer patients. We identify a cell-penetrating 11 amino-acid motif within LIM domains (eLIM) that is sufficient for binding CHK2 and CDC25, reducing the CHK2–CDC25 and CDC25–14-3-3 interaction and enhancing CDC25 activity and cancer radiosensitivity accompanied by mitotic catastrophe and apoptosis. Our results provide novel insight into molecular mechanisms underlying CDC25 activity regulation. LIM protein inhibition or use of eLIM may be new strategies for improving tumour radiosensitivity. CDC25 phosphatases are important cell cycle regulators. Here, the authors show that the LIM domain-containing proteins (for example, FHL1) induce inhibitory CDC25 phosphorylation resulting in radioresistance and that a specific peptide can increase tumour radiosensitivity by increasing CDC25 activity.
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Affiliation(s)
- Xiaojie Xu
- Department of Medical Molecular Biology, Beijing Institute of Biotechnology, Collaborative Innovation Center for Cancer Medicine, Beijing 100850, China.,Institute of Cancer Stem Cell, Cancer Center, Dalian Medical University, Liaoning 116023, China
| | - Zhongyi Fan
- Department of Medical Molecular Biology, Beijing Institute of Biotechnology, Collaborative Innovation Center for Cancer Medicine, Beijing 100850, China.,Department of Oncology, PLA General Hospital, Beijing 100853, China
| | - Chaoyang Liang
- Department of Medical Molecular Biology, Beijing Institute of Biotechnology, Collaborative Innovation Center for Cancer Medicine, Beijing 100850, China.,Department of Thoracic Surgery, Hainan Branch of PLA General Hospital, Hainan 572013, China
| | - Ling Li
- Department of Medical Molecular Biology, Beijing Institute of Biotechnology, Collaborative Innovation Center for Cancer Medicine, Beijing 100850, China
| | - Lili Wang
- Medical Research Center of Shengjing Hospital, China Medical University, Liaoning 110004, China
| | - Yingchun Liang
- Department of Medical Molecular Biology, Beijing Institute of Biotechnology, Collaborative Innovation Center for Cancer Medicine, Beijing 100850, China
| | - Jun Wu
- Department of Microorganism Engineering, Beijing Institute of Biotechnology, Beijing 100071, China
| | - Shaohong Chang
- Department of Microorganism Engineering, Beijing Institute of Biotechnology, Beijing 100071, China
| | - Zhifeng Yan
- Department of Gynecology and Obstetrics, PLA General Hospital, Beijing 100853, China
| | - Zhaohui Lv
- Department of Endocrinology, PLA General Hospital, Beijing 100853, China
| | - Jing Fu
- Department of Endocrinology, PLA General Hospital, Beijing 100853, China
| | - Yang Liu
- Department of Thoracic Surgery, PLA General Hospital, Beijing 100853, China
| | - Shuai Jin
- Department of Thoracic Surgery, PLA General Hospital, Beijing 100853, China
| | - Tao Wang
- Department of Oncology, 307 Hospital of People's Liberation Army, Beijing 100071, China
| | - Tian Hong
- Department of Medical Molecular Biology, Beijing Institute of Biotechnology, Collaborative Innovation Center for Cancer Medicine, Beijing 100850, China
| | - Yishan Dong
- Department of Renal Cancer and Melanoma, Peking University Cancer Hospital &Institute, Beijing 100142, China
| | - Lihua Ding
- Department of Medical Molecular Biology, Beijing Institute of Biotechnology, Collaborative Innovation Center for Cancer Medicine, Beijing 100850, China
| | - Long Cheng
- Department of Medical Molecular Biology, Beijing Institute of Biotechnology, Collaborative Innovation Center for Cancer Medicine, Beijing 100850, China
| | - Rui Liu
- Department of Radiotherapy, The First Affiliated Hospital of Xi'an Jiao Tong University, Xi'an 710061, China
| | - Shenbo Fu
- Department of Radiotherapy, The First Affiliated Hospital of Xi'an Jiao Tong University, Xi'an 710061, China
| | - Shunchang Jiao
- Department of Oncology, PLA General Hospital, Beijing 100853, China
| | - Qinong Ye
- Department of Medical Molecular Biology, Beijing Institute of Biotechnology, Collaborative Innovation Center for Cancer Medicine, Beijing 100850, China.,Institute of Cancer Stem Cell, Cancer Center, Dalian Medical University, Liaoning 116023, China
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46
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Anand R, Ranjha L, Cannavo E, Cejka P. Phosphorylated CtIP Functions as a Co-factor of the MRE11-RAD50-NBS1 Endonuclease in DNA End Resection. Mol Cell 2016; 64:940-950. [PMID: 27889449 DOI: 10.1016/j.molcel.2016.10.017] [Citation(s) in RCA: 213] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 09/26/2016] [Accepted: 10/13/2016] [Indexed: 12/26/2022]
Abstract
To repair a DNA double-strand break (DSB) by homologous recombination (HR), the 5'-terminated strand of the DSB must be resected. The human MRE11-RAD50-NBS1 (MRN) and CtIP proteins were implicated in the initiation of DNA end resection, but the underlying mechanism remained undefined. Here, we show that CtIP is a co-factor of the MRE11 endonuclease activity within the MRN complex. This function is absolutely dependent on CtIP phosphorylation that includes the key cyclin-dependent kinase target motif at Thr-847. Unlike in yeast, where the Xrs2/NBS1 subunit is dispensable in vitro, NBS1 is absolutely required in the human system. The MRE11 endonuclease in conjunction with RAD50, NBS1, and phosphorylated CtIP preferentially cleaves 5'-terminated DNA strands near DSBs. Our results define the initial step of HR that is particularly relevant for the processing of DSBs bearing protein blocks.
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Affiliation(s)
- Roopesh Anand
- Institute of Molecular Cancer Research, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Lepakshi Ranjha
- Institute of Molecular Cancer Research, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Elda Cannavo
- Institute of Molecular Cancer Research, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Petr Cejka
- Institute of Molecular Cancer Research, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
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47
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Xrs2 Dependent and Independent Functions of the Mre11-Rad50 Complex. Mol Cell 2016; 64:405-415. [PMID: 27746018 DOI: 10.1016/j.molcel.2016.09.011] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 07/22/2016] [Accepted: 09/08/2016] [Indexed: 02/04/2023]
Abstract
The Mre11-Rad50-Xrs2/Nbs1 (MRX/N) complex orchestrates the cellular response to DSBs through its structural, enzymatic, and signaling roles. Xrs2/Nbs1 is essential for nuclear translocation of Mre11, but its role as a component of the complex is not well defined. Here, we demonstrate that nuclear localization of Mre11 (Mre11-NLS) is able to bypass several functions of Xrs2, including DNA end resection, meiosis, hairpin resolution, and cellular resistance to clastogens. Using purified components, we show that the MR complex has equivalent activity to MRX in cleavage of protein-blocked DNA ends. Although Xrs2 physically interacts with Sae2, we found that end resection in its absence remains Sae2 dependent in vivo and in vitro. MRE11-NLS was unable to rescue the xrs2Δ defects in Tel1/ATM kinase signaling and non-homologous end joining, consistent with the role of Xrs2 as a chaperone and adaptor protein coordinating interactions between the MR complex and other repair proteins.
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48
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Gobbini E, Cassani C, Villa M, Bonetti D, Longhese MP. Functions and regulation of the MRX complex at DNA double-strand breaks. MICROBIAL CELL (GRAZ, AUSTRIA) 2016; 3:329-337. [PMID: 28357369 PMCID: PMC5349012 DOI: 10.15698/mic2016.08.517] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 06/03/2016] [Indexed: 12/22/2022]
Abstract
DNA double-strand breaks (DSBs) pose a serious threat to genome stability and cell survival. Cells possess mechanisms that recognize DSBs and promote their repair through either homologous recombination (HR) or non-homologous end joining (NHEJ). The evolutionarily conserved Mre11-Rad50-Xrs2 (MRX) complex plays a central role in the cellular response to DSBs, as it is implicated in controlling end resection and in maintaining the DSB ends tethered to each other. Furthermore, it is responsible for DSB signaling by activating the checkpoint kinase Tel1 that, in turn, supports MRX function in a positive feedback loop. The present review focuses mainly on recent works in the budding yeast Saccharomyces cerevisiae to highlight structure and regulation of MRX as well as its interplays with Tel1.
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Affiliation(s)
- Elisa Gobbini
- Dipartimento di Biotecnologie e Bioscienze, Università di
Milano-Bicocca, Piazza della Scienza 2, 20126 Milan, Italy
| | - Corinne Cassani
- Dipartimento di Biotecnologie e Bioscienze, Università di
Milano-Bicocca, Piazza della Scienza 2, 20126 Milan, Italy
| | - Matteo Villa
- Dipartimento di Biotecnologie e Bioscienze, Università di
Milano-Bicocca, Piazza della Scienza 2, 20126 Milan, Italy
| | - Diego Bonetti
- Institute of Molecular Biology gGmbH (IMB), 55128 Mainz, Germany
| | - Maria P. Longhese
- Dipartimento di Biotecnologie e Bioscienze, Università di
Milano-Bicocca, Piazza della Scienza 2, 20126 Milan, Italy
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Paudyal SC, You Z. Sharpening the ends for repair: mechanisms and regulation of DNA resection. Acta Biochim Biophys Sin (Shanghai) 2016; 48:647-57. [PMID: 27174871 DOI: 10.1093/abbs/gmw043] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Accepted: 04/12/2016] [Indexed: 12/23/2022] Open
Abstract
DNA end resection is a key process in the cellular response to DNA double-strand break damage that is essential for genome maintenance and cell survival. Resection involves selective processing of 5' ends of broken DNA to generate ssDNA overhangs, which in turn control both DNA repair and checkpoint signaling. DNA resection is the first step in homologous recombination-mediated repair and a prerequisite for the activation of the ataxia telangiectasia mutated and Rad3-related (ATR)-dependent checkpoint that coordinates repair with cell cycle progression and other cellular processes. Resection occurs in a cell cycle-dependent manner and is regulated by multiple factors to ensure an optimal amount of ssDNA required for proper repair and genome stability. Here, we review the latest findings on the molecular mechanisms and regulation of the DNA end resection process and their implications for cancer formation and treatment.
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Affiliation(s)
- Sharad C Paudyal
- Department of Cell Biology and Physiology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Zhongsheng You
- Department of Cell Biology and Physiology, Washington University School of Medicine, St Louis, MO 63110, USA
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50
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DNA double-strand-break repair in higher eukaryotes and its role in genomic instability and cancer: Cell cycle and proliferation-dependent regulation. Semin Cancer Biol 2016; 37-38:51-64. [DOI: 10.1016/j.semcancer.2016.03.003] [Citation(s) in RCA: 178] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Revised: 03/11/2016] [Accepted: 03/21/2016] [Indexed: 12/18/2022]
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