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Hengel SR, Oppenheimer K, Smith C, Schaich MA, Rein HL, Martino J, Darrah K, Ezekwenna O, Burton K, Van Houten B, Spies M, Bernstein KA. The human Shu complex promotes RAD51 activity by modulating RPA dynamics on ssDNA. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.14.580393. [PMID: 38405734 PMCID: PMC10888808 DOI: 10.1101/2024.02.14.580393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Templated DNA repair that occurs during homologous recombination and replication stress relies on RAD51. RAD51 activity is positively regulated by BRCA2 and the RAD51 paralogs. The Shu complex is a RAD51 paralog-containing complex consisting of SWSAP1 and SWS1. We demonstrate that SWSAP1-SWS1 binds RAD51, maintains RAD51 filament stability, and enables strand exchange. Using single molecule confocal fluorescence microscopy combined with optical tweezers, we show that SWSAP1-SWS1 decorates RAD51 filaments proficient for homologous recombination. We also find SWSAP1-SWS1 enhances RPA diffusion on ssDNA. Importantly, we show human sgSWSAP1 and sgSWS1 knockout cells are sensitive to pharmacological inhibition of PARP and APE1. Lastly, we identify cancer variants in SWSAP1 that alter SWS1 complex formation. Together, we show that SWSAP1-SWS1 stimulates RAD51-dependent high-fidelity repair and may be an important new cancer therapeutic target.
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2
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Rinaldi F, Schipani F, Balboni B, Catalano F, Marotta R, Myers SH, Previtali V, Veronesi M, Scietti L, Cecatiello V, Pasqualato S, Ortega JA, Girotto S, Cavalli A. Isolation and Characterization of Monomeric Human RAD51: A Novel Tool for Investigating Homologous Recombination in Cancer. Angew Chem Int Ed Engl 2023; 62:e202312517. [PMID: 37924230 DOI: 10.1002/anie.202312517] [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: 08/25/2023] [Revised: 11/02/2023] [Accepted: 11/03/2023] [Indexed: 11/06/2023]
Abstract
DNA repair protein RAD51 is a key player in the homologous recombination pathway. Upon DNA damage, RAD51 is transported into the nucleus by BRCA2, where it can repair DNA double-strand breaks. Due to the structural complexity and dynamics, researchers have not yet clarified the mechanistic details of every step of RAD51 recruitment and DNA repair. RAD51 possesses an intrinsic tendency to form oligomeric structures, which make it challenging to conduct biochemical and biophysical investigations. Here, for the first time, we report on the isolation and characterization of a human monomeric RAD51 recombinant form, obtained through a double mutation, which preserves the protein's integrity and functionality. We investigated different buffers to identify the most suitable condition needed to definitively stabilize the monomer. The monomer of human RAD51 provides the community with a unique biological tool for investigating RAD51-mediated homologous recombination, and paves the way for more reliable structural, mechanistic, and drug discovery studies.
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Affiliation(s)
- Francesco Rinaldi
- Computational and Chemical Biology, Istituto Italiano di Tecnologia, Via Morego 30, 16163, Genoa, Italy
- Department of Pharmacy and Biotechnology, University of Bologna, Via Belmeloro 6, 40126, Bologna, Italy
| | - Fabrizio Schipani
- Computational and Chemical Biology, Istituto Italiano di Tecnologia, Via Morego 30, 16163, Genoa, Italy
| | - Beatrice Balboni
- Computational and Chemical Biology, Istituto Italiano di Tecnologia, Via Morego 30, 16163, Genoa, Italy
- Department of Pharmacy and Biotechnology, University of Bologna, Via Belmeloro 6, 40126, Bologna, Italy
| | - Federico Catalano
- Electron Microscopy Facility, Istituto Italiano di Tecnologia, via Morego 30, 16163, Genoa, Italy
| | - Roberto Marotta
- Electron Microscopy Facility, Istituto Italiano di Tecnologia, via Morego 30, 16163, Genoa, Italy
| | - Samuel H Myers
- Computational and Chemical Biology, Istituto Italiano di Tecnologia, Via Morego 30, 16163, Genoa, Italy
| | - Viola Previtali
- Computational and Chemical Biology, Istituto Italiano di Tecnologia, Via Morego 30, 16163, Genoa, Italy
| | - Marina Veronesi
- Structural Biophysics, Istituto Italiano di Tecnologia, via Morego 30, 16163, Genoa, Italy
| | - Luigi Scietti
- Biochemistry and Structural Biology Unit, Department of Experimental Oncology, IRCCS European Institute of Oncology, Via Adamello 16, 20139, Milan, Italy
| | - Valentina Cecatiello
- Biochemistry and Structural Biology Unit, Department of Experimental Oncology, IRCCS European Institute of Oncology, Via Adamello 16, 20139, Milan, Italy
- Current address: Structural Biology Research Centre, Human Technopole Milan, Italy Palazzo Italia Viale Rita Levi-Montalcini 1, 20157, Milan, Italy
| | - Sebastiano Pasqualato
- Biochemistry and Structural Biology Unit, Department of Experimental Oncology, IRCCS European Institute of Oncology, Via Adamello 16, 20139, Milan, Italy
- Current address: Structural Biology Research Centre, Human Technopole Milan, Italy Palazzo Italia Viale Rita Levi-Montalcini 1, 20157, Milan, Italy
| | - Jose Antonio Ortega
- Computational and Chemical Biology, Istituto Italiano di Tecnologia, Via Morego 30, 16163, Genoa, Italy
| | - Stefania Girotto
- Structural Biophysics, Istituto Italiano di Tecnologia, via Morego 30, 16163, Genoa, Italy
| | - Andrea Cavalli
- Computational and Chemical Biology, Istituto Italiano di Tecnologia, Via Morego 30, 16163, Genoa, Italy
- Department of Pharmacy and Biotechnology, University of Bologna, Via Belmeloro 6, 40126, Bologna, Italy
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3
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Honda M, Razzaghi M, Gaur P, Malacaria E, Di Biagi L, Aiello FA, Paintsil EA, Stanfield A, Deppe BJ, Gakhar L, Schnicker NJ, Spies MA, Pichierri P, Spies M. Human RAD52 double-ring remodels replication forks restricting fork reversal. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.14.566657. [PMID: 38014173 PMCID: PMC10680749 DOI: 10.1101/2023.11.14.566657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Human RAD52 1,2 is a multifunctional DNA repair protein involved in several cellular events that support genome stability including protection of stalled DNA replication forks from excessive degradation 3-7 . In its gatekeeper role, RAD52 binds to and stabilizes stalled replication forks during replication stress protecting them from reversal by SMARCAL1 5 . The structural and molecular mechanism of the RAD52-mediated fork protection remains elusive. Here, using P1 nuclease sensitivity, biochemical and single-molecule analyses we show that RAD52 dynamically remodels replication forks through its strand exchange activity. The presence of the ssDNA binding protein RPA at the fork modulates the kinetics of the strand exchange without impeding the reaction outcome. Mass photometry and single-particle cryo-electron microscopy show that the replication fork promotes a unique nucleoprotein structure containing head-to-head arrangement of two undecameric RAD52 rings with an extended positively charged surface that accommodates all three arms of the replication fork. We propose that the formation and continuity of this surface is important for the strand exchange reaction and for competition with SMARCAL1.
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4
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Li Z, Wang B, Luo W, Xu Y, Wang J, Xue Z, Niu Y, Cheng Z, Ge S, Zhang W, Zhang J, Li Q, Chong K. Natural variation of codon repeats in COLD11 endows rice with chilling resilience. SCIENCE ADVANCES 2023; 9:eabq5506. [PMID: 36608134 PMCID: PMC9821855 DOI: 10.1126/sciadv.abq5506] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 12/06/2022] [Indexed: 06/07/2023]
Abstract
Abnormal temperature caused by global climate change threatens the rice production. Defense signaling network for chilling has been uncovered in plants. However, less is known about repairing DNA damage produced from overwhelmed defense and its evolution during domestication. Here, we genetically identified a major QTL, COLD11, using the data-merging genome-wide association study based on an algorithm combining polarized data from two subspecies, indica and japonica, into one system. Rice loss-of-function mutations of COLD11 caused reduced chilling tolerance. Genome evolution analysis of representative rice germplasms suggested that numbers of GCG sequence repeats in the first exon of COLD11 were subjected to strong domestication selection during the northern expansion of rice planting. The repeat numbers affected the biochemical activity of DNA repair protein COLD11/RAD51A1 in renovating DNA damage under chilling stress. Our findings highlight a potential way to finely manipulate key genes in rice genome and effectively improve chilling tolerance through molecular designing.
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Affiliation(s)
- Zhitao Li
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Bo Wang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wei Luo
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yunyuan Xu
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jinjuan Wang
- School of Mathematics and Statistics, Beijing Institute of Technology, Beijing, 100181, China
| | - Zhihui Xue
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Yuda Niu
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Zhukuan Cheng
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou 225009, China
| | - Song Ge
- University of Chinese Academy of Sciences, Beijing 100049, China
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Wei Zhang
- LSC, NCMIS, Academy of Mathematics and Systems Science, Chinese Academy of Sciences, Beijing 100190, China
| | - Jingyu Zhang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qizhai Li
- University of Chinese Academy of Sciences, Beijing 100049, China
- LSC, NCMIS, Academy of Mathematics and Systems Science, Chinese Academy of Sciences, Beijing 100190, China
| | - Kang Chong
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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5
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Skoko JJ, Cao J, Gaboriau D, Attar M, Asan A, Hong L, Paulsen CE, Ma H, Liu Y, Wu H, Harkness T, Furdui CM, Manevich Y, Morrison CG, Brown ET, Normolle D, Spies M, Spies MA, Carroll K, Neumann CA. Redox regulation of RAD51 Cys319 and homologous recombination by peroxiredoxin 1. Redox Biol 2022; 56:102443. [PMID: 36058112 PMCID: PMC9450138 DOI: 10.1016/j.redox.2022.102443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 08/01/2022] [Accepted: 08/11/2022] [Indexed: 11/28/2022] Open
Abstract
RAD51 is a critical recombinase that functions in concert with auxiliary mediator proteins to direct the homologous recombination (HR) DNA repair pathway. We show that Cys319 RAD51 possesses nucleophilic characteristics and is important for irradiation-induced RAD51 foci formation and resistance to inhibitors of poly (ADP-ribose) polymerase (PARP). We have previously identified that cysteine (Cys) oxidation of proteins can be important for activity and modulated via binding to peroxiredoxin 1 (PRDX1). PRDX1 reduces peroxides and coordinates the signaling actions of protein binding partners. Loss of PRDX1 inhibits irradiation-induced RAD51 foci formation and represses HR DNA repair. PRDX1-deficient human breast cancer cells and mouse embryonic fibroblasts display disrupted RAD51 foci formation and decreased HR, resulting in increased DNA damage and sensitization of cells to irradiation. Following irradiation cells deficient in PRDX1 had increased incorporation of the sulfenylation probe DAz-2 in RAD51 Cys319, a functionally-significant, thiol that PRDX1 is critical for maintaining in a reduced state. Molecular dynamics (MD) simulations of dT-DNA bound to a non-oxidized RAD51 protein showed tight binding throughout the simulation, while dT-DNA dissociated from an oxidized Cys319 RAD51 filament. These novel data establish RAD51 Cys319 as a functionally-significant site for the redox regulation of HR and cellular responses to IR. A functionally-significant Cys319 was identified in RAD51 that possesses nucleophilic characteristics. RAD51 Cys319 plays a central role in RAD51-mediated repair of DNA double strand breaks (DSB). Loss of peroxiredoxin 1 (PRDX1) impairs DNA DSB repair by homologous recombination and results in DNA damage. PRDX1 is critical for maintaining RAD51 Cys319 in a reduced state. Molecular dynamic (MD) simulations suggest ssDNA to dissociate from sulfenylated and not reduced RAD51 Cys319.
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Affiliation(s)
- John J Skoko
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, 15261, USA; Women's Cancer Research Center, University of Pittsburgh Cancer Institute, Pittsburgh, PA, 15213, USA; Magee-Women's Research Institute, Magee-Women's Research Hospital of University of Pittsburgh Medical Center, Pittsburgh, PA, 15213, USA
| | - Juxiang Cao
- Department of Cell and Molecular Pharmacology, The Medical University of South Carolina, Charleston, SC, 29425, USA
| | - David Gaboriau
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland; Facility for Imaging By Light Microscopy, Imperial College London, London, SW7 2AZ, United Kingdom
| | - Myriam Attar
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, 15261, USA; Women's Cancer Research Center, University of Pittsburgh Cancer Institute, Pittsburgh, PA, 15213, USA; Magee-Women's Research Institute, Magee-Women's Research Hospital of University of Pittsburgh Medical Center, Pittsburgh, PA, 15213, USA
| | - Alparslan Asan
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, 15261, USA; Women's Cancer Research Center, University of Pittsburgh Cancer Institute, Pittsburgh, PA, 15213, USA; Magee-Women's Research Institute, Magee-Women's Research Hospital of University of Pittsburgh Medical Center, Pittsburgh, PA, 15213, USA
| | - Lisa Hong
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, 15261, USA; Women's Cancer Research Center, University of Pittsburgh Cancer Institute, Pittsburgh, PA, 15213, USA; Magee-Women's Research Institute, Magee-Women's Research Hospital of University of Pittsburgh Medical Center, Pittsburgh, PA, 15213, USA
| | - Candice E Paulsen
- Department of Chemistry, Scripps Research Institute Florida, Jupiter, FL, 33458, USA
| | - Hongqiang Ma
- Biomedical Optical Imaging Laboratory, Departments of Medicine and Bioengineering, University of Pittsburgh, Pittsburgh, PA, 15261, USA
| | - Yang Liu
- Biomedical Optical Imaging Laboratory, Departments of Medicine and Bioengineering, University of Pittsburgh, Pittsburgh, PA, 15261, USA
| | - Hanzhi Wu
- Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC, 27157, USA; Center for Redox Biology and Medicine, Wake Forest School of Medicine, Winston-Salem, NC, 27157, USA
| | - Trey Harkness
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, 15261, USA
| | - Cristina M Furdui
- Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC, 27157, USA; Center for Redox Biology and Medicine, Wake Forest School of Medicine, Winston-Salem, NC, 27157, USA
| | - Yefim Manevich
- Department of Cell and Molecular Pharmacology, The Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Ciaran G Morrison
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Erika T Brown
- Dartmouth Geisel School of Medicine, Hanover, NH, 03755, USA
| | - Daniel Normolle
- Department of Biostatistics, University of Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Maria Spies
- Department of Biochemistry and Molecular Biology, University of Iowa, IA, 52242, USA
| | - Michael Ashley Spies
- Department of Biochemistry and Molecular Biology, Department of Pharmaceutical Sciences and Experimental Therapeutics, University of Iowa, IA, 52242, USA
| | - Kate Carroll
- Department of Chemistry, Scripps Research Institute Florida, Jupiter, FL, 33458, USA
| | - Carola A Neumann
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, 15261, USA; Women's Cancer Research Center, University of Pittsburgh Cancer Institute, Pittsburgh, PA, 15213, USA; Magee-Women's Research Institute, Magee-Women's Research Hospital of University of Pittsburgh Medical Center, Pittsburgh, PA, 15213, USA.
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6
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Fanale D, Pivetti A, Cancelliere D, Spera A, Bono M, Fiorino A, Pedone E, Barraco N, Brando C, Perez A, Guarneri MF, Russo TDB, Vieni S, Guarneri G, Russo A, Bazan V. BRCA1/2 variants of unknown significance in hereditary breast and ovarian cancer (HBOC) syndrome: looking for the hidden meaning. Crit Rev Oncol Hematol 2022; 172:103626. [PMID: 35150867 DOI: 10.1016/j.critrevonc.2022.103626] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 01/28/2022] [Accepted: 02/07/2022] [Indexed: 01/04/2023] Open
Abstract
Hereditary breast and ovarian cancer syndrome is caused by germline mutations in BRCA1/2 genes. These genes are very large and their mutations are heterogeneous and scattered throughout the coding sequence. In addition to the above-mentioned mutations, variants of uncertain/unknown significance (VUSs) have been identified in BRCA genes, which make more difficult the clinical management of the patient and risk assessment. In the last decades, several laboratories have developed different databases that contain more than 2000 variants for the two genes and integrated strategies which include multifactorial prediction models based on direct and indirect genetic evidence, to classify the VUS and attribute them a clinical significance associated with a deleterious, high-low or neutral risk. This review provides a comprehensive overview of literature studies concerning the VUSs, in order to assess their impact on the population and provide new insight for the appropriate patient management in clinical practice.
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Affiliation(s)
- Daniele Fanale
- Section of Medical Oncology, Department of Surgical, Oncological and Oral Sciences, University of Palermo, 90127 Palermo, Italy
| | - Alessia Pivetti
- Section of Medical Oncology, Department of Surgical, Oncological and Oral Sciences, University of Palermo, 90127 Palermo, Italy
| | - Daniela Cancelliere
- Section of Medical Oncology, Department of Surgical, Oncological and Oral Sciences, University of Palermo, 90127 Palermo, Italy
| | - Antonio Spera
- Department of Radiotherapy, San Giovanni di Dio Hospital, ASP of Agrigento, Agrigento, Italy
| | - Marco Bono
- Section of Medical Oncology, Department of Surgical, Oncological and Oral Sciences, University of Palermo, 90127 Palermo, Italy
| | - Alessia Fiorino
- Section of Medical Oncology, Department of Surgical, Oncological and Oral Sciences, University of Palermo, 90127 Palermo, Italy
| | - Erika Pedone
- Section of Medical Oncology, Department of Surgical, Oncological and Oral Sciences, University of Palermo, 90127 Palermo, Italy
| | - Nadia Barraco
- Section of Medical Oncology, Department of Surgical, Oncological and Oral Sciences, University of Palermo, 90127 Palermo, Italy
| | - Chiara Brando
- Section of Medical Oncology, Department of Surgical, Oncological and Oral Sciences, University of Palermo, 90127 Palermo, Italy
| | - Alessandro Perez
- Section of Medical Oncology, Department of Surgical, Oncological and Oral Sciences, University of Palermo, 90127 Palermo, Italy
| | | | - Tancredi Didier Bazan Russo
- Section of Medical Oncology, Department of Surgical, Oncological and Oral Sciences, University of Palermo, 90127 Palermo, Italy
| | - Salvatore Vieni
- Division of General and Oncological Surgery, Department of Surgical, Oncological and Oral Sciences, University of Palermo, Italy
| | - Girolamo Guarneri
- Gynecology Section, Mother - Child Department, University of Palermo, 90127 Palermo, Italy
| | - Antonio Russo
- Section of Medical Oncology, Department of Surgical, Oncological and Oral Sciences, University of Palermo, 90127 Palermo, Italy.
| | - Viviana Bazan
- Department of Biomedicine, Neuroscience and Advanced Diagnostics, University of Palermo, 90127 Palermo, Italy
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7
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Lindenburg LH, Pantelejevs T, Gielen F, Zuazua-Villar P, Butz M, Rees E, Kaminski CF, Downs JA, Hyvönen M, Hollfelder F. Improved RAD51 binders through motif shuffling based on the modularity of BRC repeats. Proc Natl Acad Sci U S A 2021; 118:e2017708118. [PMID: 34772801 PMCID: PMC8727024 DOI: 10.1073/pnas.2017708118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/10/2021] [Indexed: 01/20/2023] Open
Abstract
Exchanges of protein sequence modules support leaps in function unavailable through point mutations during evolution. Here we study the role of the two RAD51-interacting modules within the eight binding BRC repeats of BRCA2. We created 64 chimeric repeats by shuffling these modules and measured their binding to RAD51. We found that certain shuffled module combinations were stronger binders than any of the module combinations in the natural repeats. Surprisingly, the contribution from the two modules was poorly correlated with affinities of natural repeats, with a weak BRC8 repeat containing the most effective N-terminal module. The binding of the strongest chimera, BRC8-2, to RAD51 was improved by -2.4 kCal/mol compared to the strongest natural repeat, BRC4. A crystal structure of RAD51:BRC8-2 complex shows an improved interface fit and an extended β-hairpin in this repeat. BRC8-2 was shown to function in human cells, preventing the formation of nuclear RAD51 foci after ionizing radiation.
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Affiliation(s)
- Laurens H Lindenburg
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, United Kingdom
| | - Teodors Pantelejevs
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, United Kingdom
| | - Fabrice Gielen
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, United Kingdom
- Living Systems Institute, University of Exeter, Exeter EX4 4QD, United Kingdom
| | - Pedro Zuazua-Villar
- Division of Cancer Biology, The Institute of Cancer Research, London SW3 6JB, United Kingdom
| | - Maren Butz
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, United Kingdom
| | - Eric Rees
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge CB3 0AS, United Kingdom
| | - Clemens F Kaminski
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge CB3 0AS, United Kingdom
| | - Jessica A Downs
- Division of Cancer Biology, The Institute of Cancer Research, London SW3 6JB, United Kingdom
| | - Marko Hyvönen
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, United Kingdom;
| | - Florian Hollfelder
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, United Kingdom;
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8
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Inhibiting homologous recombination by targeting RAD51 protein. Biochim Biophys Acta Rev Cancer 2021; 1876:188597. [PMID: 34332021 DOI: 10.1016/j.bbcan.2021.188597] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2021] [Revised: 07/09/2021] [Accepted: 07/24/2021] [Indexed: 02/06/2023]
Abstract
Homologous recombination (HR) is involved in repairing DNA double-strand breaks (DSB), the most harmful for the cell. Regulating HR is essential for maintaining genomic stability. In many forms of cancer, overactivation of HR increases tumor resistance to DNA-damaging treatments. RAD51, HR's core protein, is very often over-expressed in these cancers and plays a critical role in cancer cell development and survival. Targeting RAD51 directly to reduce its activity and its expression is therefore one strategy to sensitize and overcome resistance cancer cells to existing DNA-damaging therapies which remains the limiting factor for the success of targeted therapy. This review describes the structure and biological roles of RAD51, summarizes the different targeted sites of RAD51 and its inhibitory compounds discovered and described in the last decade.
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9
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Gui T, Yao C, Jia B, Shen K. Identification and analysis of genes associated with epithelial ovarian cancer by integrated bioinformatics methods. PLoS One 2021; 16:e0253136. [PMID: 34143800 PMCID: PMC8213194 DOI: 10.1371/journal.pone.0253136] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 05/31/2021] [Indexed: 12/24/2022] Open
Abstract
Background Though considerable efforts have been made to improve the treatment of epithelial ovarian cancer (EOC), the prognosis of patients has remained poor. Identifying differentially expressed genes (DEGs) involved in EOC progression and exploiting them as novel biomarkers or therapeutic targets is of great value. Methods Overlapping DEGs were screened out from three independent gene expression omnibus (GEO) datasets and were subjected to Gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) pathway enrichment analyses. The protein-protein interactions (PPI) network of DEGs was constructed based on the STRING database. The expression of hub genes was validated in GEPIA and GEO. The relationship of hub genes expression with tumor stage and overall survival and progression-free survival of EOC patients was investigated using the cancer genome atlas data. Results A total of 306 DEGs were identified, including 265 up-regulated and 41 down-regulated. Through PPI network analysis, the top 20 genes were screened out, among which 4 hub genes, which were not researched in depth so far, were selected after literature retrieval, including CDC45, CDCA5, KIF4A, ESPL1. The four genes were up-regulated in EOC tissues compared with normal tissues, but their expression decreased gradually with the continuous progression of EOC. Survival curves illustrated that patients with a lower level of CDCA5 and ESPL1 had better overall survival and progression-free survival statistically. Conclusion Two hub genes, CDCA5 and ESPL1, identified as probably playing tumor-promotive roles, have great potential to be utilized as novel therapeutic targets for EOC treatment.
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Affiliation(s)
- Ting Gui
- Department of Obstetrics and Gynecology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Chenhe Yao
- Department of R&D Technology Center, Beijing Zhicheng Biomedical Technology Co, Ltd, Beijing, China
| | - Binghan Jia
- Department of R&D Technology Center, Beijing Zhicheng Biomedical Technology Co, Ltd, Beijing, China
| | - Keng Shen
- Department of Obstetrics and Gynecology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
- * E-mail:
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10
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Zhang H, Schaub JM, Finkelstein IJ. RADX condenses single-stranded DNA to antagonize RAD51 loading. Nucleic Acids Res 2020; 48:7834-7843. [PMID: 32621611 PMCID: PMC7430644 DOI: 10.1093/nar/gkaa559] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 06/15/2020] [Accepted: 06/18/2020] [Indexed: 12/31/2022] Open
Abstract
RADX is a mammalian single-stranded DNA-binding protein that stabilizes telomeres and stalled replication forks. Cellular biology studies have shown that the balance between RADX and Replication Protein A (RPA) is critical for DNA replication integrity. RADX is also a negative regulator of RAD51-mediated homologous recombination at stalled forks. However, the mechanism of RADX acting on DNA and its interactions with RPA and RAD51 are enigmatic. Using single-molecule imaging of the key proteins in vitro, we reveal that RADX condenses ssDNA filaments, even when the ssDNA is coated with RPA at physiological protein ratios. RADX compacts RPA-coated ssDNA filaments via higher-order assemblies that can capture ssDNA in trans. Furthermore, RADX blocks RPA displacement by RAD51 and prevents RAD51 loading on ssDNA. Our results indicate that RADX is an ssDNA condensation protein that inhibits RAD51 filament formation and may antagonize other ssDNA-binding proteins on RPA-coated ssDNA.
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Affiliation(s)
- Hongshan Zhang
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Jeffrey M Schaub
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Ilya J Finkelstein
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA.,Center for Systems and Synthetic Biology, University of Texas at Austin, Austin, TX 78712, USA
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11
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Design of BRC analogous peptides based on the complex BRC8-RAD51 and the preliminary study on the peptide structures. Amino Acids 2020; 52:831-839. [PMID: 32417964 DOI: 10.1007/s00726-020-02856-x] [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: 01/14/2020] [Accepted: 04/30/2020] [Indexed: 10/24/2022]
Abstract
BRCA2 is an important tumor suppressor gene that plays a critical role in preserving the stability of cellular genetic information, participating in DNA repair by engaging in binding interactions with RAD51 proteins. However, the lack of structural data on BRCA2 and RAD51 makes the study of their interaction mechanism still a great challenge. We characterize the structure of the BRC8-RAD51 complex using ZDOCK protein docking software and identify the potential non-conserved active site of BRC8 via virtual alanine scanning, utilizing the obtained results to synthesize BRC8, its six analogous peptides (BRC8-1 to BRC8-6), and critical peptide fragment of RAD51 (RAD51(231-260)) by Fmoc solid-phase synthesis. The analogous peptides are found to exhibit a secondary structure significantly different from that of BRC8 by circular dichroism spectroscopy, which indicates that mutation sites determined by computer-aided simulation correspond to key amino acid residues substantially affecting polypeptide structure. On the other hand, the secondary structure of RAD51(231-260) was also considerably influenced by its interaction with BRC8 and analogs, e.g., the fraction of the α-helical structure in RAD51(231-260) increased to 23.6, 15.1, and 13.5% upon interaction with BRC8-1, BRC8-3, and BRC8-6, respectively. The results show that the properties of C-terminal amino acid residues significantly influence peptide-peptide interactions, in agreement with the results of virtual alanine scanning. Therefore, computer-aided simulation was confirmed to be a technique that is useful for narrowing down the range of sites responsible for interactions between peptides or proteins, and provides new inspirations for the design of peptides with strong interactions.
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12
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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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13
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Song Z, Tu X, Zhou Q, Huang J, Chen Y, Liu J, Lee S, Kim W, Nowsheen S, Luo K, Yuan J, Lou Z. A novel UCHL 3 inhibitor, perifosine, enhances PARP inhibitor cytotoxicity through inhibition of homologous recombination-mediated DNA double strand break repair. Cell Death Dis 2019; 10:398. [PMID: 31113933 PMCID: PMC6529448 DOI: 10.1038/s41419-019-1628-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 04/04/2019] [Accepted: 04/30/2019] [Indexed: 02/07/2023]
Abstract
Triple-negative breast cancer (TNBC) treatment remains a great challenge for clinical practice and novel therapeutic strategies are urgently needed. UCHL3 is a deubiquitinase that is overexpressed in TNBC and correlates with poor prognosis. UCHL3 deubiquitinates RAD51 thereby promoting the recruitment of RAD51 to DNA damage sites and augmenting DNA repair. Therefore, UCHL3 overexpression can render cancer cells resistant to DNA damage inducing chemo and radiotherapy, and targeting UCHL3 can sensitize TNBC to radiation and chemotherapy. However, small molecule inhibitors of UCHL3 are yet to be identified. Here we report that perifosine, a previously reported Akt inhibitor, can inhibit UCHL3 in vitro and in vivo. We found low dose (50 nM) perifosine inhibited UCHL3 deubiquitination activity without affecting Akt activity. Furthermore, perifosine enhanced Olaparib-induced growth inhibition in TNBC cells. Mechanistically, perifosine induced RAD51 ubiquitination and blocked the RAD51-BRCA2 interaction, which in turn decreased ionizing radiation-induced foci (IRIF) of Rad51 and, thereby, homologous recombination (HR)-mediated DNA double strand break repair. In addition, combination of perifosine and Olaparib showed synergistic antitumor activity in vivo in TNBC xenograft model. Thus, our present study provides a novel therapeutic approach to optimize PARP inhibitor treatment efficiency.
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Affiliation(s)
- Zhiwang Song
- Division of Oncology Research, Mayo Clinic, Rochester, MN, USA
| | - Xinyi Tu
- Division of Oncology Research, Mayo Clinic, Rochester, MN, USA
| | - Qin Zhou
- Division of Oncology Research, Mayo Clinic, Rochester, MN, USA
| | - Jinzhou Huang
- Division of Oncology Research, Mayo Clinic, Rochester, MN, USA
| | - Yuping Chen
- Division of Oncology Research, Mayo Clinic, Rochester, MN, USA
| | - Jiaqi Liu
- Division of Oncology Research, Mayo Clinic, Rochester, MN, USA
| | - SeungBaek Lee
- Division of Oncology Research, Mayo Clinic, Rochester, MN, USA
| | - Wootae Kim
- Division of Oncology Research, Mayo Clinic, Rochester, MN, USA
| | - Somaira Nowsheen
- Medical Scientist Training Program, Mayo Clinic Alix School of Medicine, Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN, 55905, USA
| | - Kuntian Luo
- Division of Oncology Research, Mayo Clinic, Rochester, MN, USA.
- Department of Molecular Pharmacology, Mayo Clinic, Rochester, MN, USA.
| | - Jian Yuan
- Division of Oncology Research, Mayo Clinic, Rochester, MN, USA.
- Department of Molecular Pharmacology, Mayo Clinic, Rochester, MN, USA.
| | - Zhenkun Lou
- Division of Oncology Research, Mayo Clinic, Rochester, MN, USA.
- Department of Molecular Pharmacology, Mayo Clinic, Rochester, MN, USA.
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14
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Vinnarasi S, Radhika R, Vijayakumar S, Shankar R. Structural insights into the anti-cancer activity of quercetin on G-tetrad, mixed G-tetrad, and G-quadruplex DNA using quantum chemical and molecular dynamics simulations. J Biomol Struct Dyn 2019; 38:317-339. [PMID: 30794082 DOI: 10.1080/07391102.2019.1574239] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Human telomerase referred as 'terminal transferase' is a nucleoprotein enzyme which inhibits the disintegration of telomere length and act as a drug target for the anticancer therapy. The tandem repeating structure of telomere sequence forms the guanine-rich quadruplex structures that stabilize stacked tetrads. In our present work, we have investigated the interaction of quercetin with DNA tetrads using DFT. Geometrical analysis revealed that the influence of quercetin drug induces the structural changes into the DNA tetrads. Among DNA tetrads, the quercetin stacked with GCGC tetrad has the highest interaction energy of -88.08 kcal/mol. The binding mode and the structural stability are verified by the absorption spectroscopy method. The longer wavelength was found at 380 nm and it exhibits bathochromic shift. The findings help us to understand the binding nature of quercetin drug with DNA tetrads and it also inhibits the telomerase activity. Further, the quercetin drug interacted with G-quadruplex DNA by using molecular dynamics (MD) simulation studies for 100 ns simulation at different temperatures and different pH levels (T = 298 K, 320 K and pH = 7.4, 5.4). The structural stability of the quercetin with G-quadruplex structure is confirmed by RMSD. For the acidic condition (pH = 5.4), the binding affinity is higher toward G-quadruplex DNA, this result resembles that the quercetin drug is well interacted with G-quadruplex DNA at acidic condition (pH = 7.4) than the neutral condition. The obtained results show that quercetin drug stabilizes the G-quadruplex DNA, which regulates telomerase enzyme and it potentially acts as a novel anti-cancer agent.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- S Vinnarasi
- Department of Physics, Bharathiar University, Coimbatore, Tamil Nadu, India
| | - R Radhika
- Department of Physics, Bharathiar University, Coimbatore, Tamil Nadu, India
| | - S Vijayakumar
- Department of Medical Physics, Bharathiar University, Coimbatore, Tamil Nadu, India
| | - R Shankar
- Department of Physics, Bharathiar University, Coimbatore, Tamil Nadu, India
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15
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The multiple functions of kinesin-4 family motor protein KIF4 and its clinical potential. Gene 2018; 678:90-99. [DOI: 10.1016/j.gene.2018.08.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 08/01/2018] [Accepted: 08/02/2018] [Indexed: 02/07/2023]
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16
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Chandran EA, Kennedy I. Significant Tumor Response to the Poly (ADP-ribose) Polymerase Inhibitor Olaparib in Heavily Pretreated Patient With Ovarian Carcinosarcoma Harboring a Germline RAD51D Mutation. JCO Precis Oncol 2018; 2:1-4. [DOI: 10.1200/po.18.00253] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Affiliation(s)
| | - Ian Kennedy
- All authors: Waikato District Health Board, Hamilton, New Zealand
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17
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van der Zon NL, Kanaar R, Wyman C. Variation in RAD51 details a hub of functions: opportunities to advance cancer diagnosis and therapy. F1000Res 2018; 7. [PMID: 30271574 PMCID: PMC6137408 DOI: 10.12688/f1000research.15650.2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/29/2018] [Indexed: 11/30/2022] Open
Abstract
Loss of genome stability is one of the hallmarks of the enabling characteristics of cancer development. Homologous recombination is a DNA repair process that often breaks down as a prelude to developing cancer. Conversely, homologous recombination can be the Achilles’ heel in common anti-cancer therapies, which are effective by inducing irreparable DNA damage. Here, we review recent structural and functional studies of RAD51, the protein that catalyzes the defining step of homologous recombination: homology recognition and DNA strand exchange. Specific mutations can be linked to structural changes and known essential functions. Additional RAD51 interactions and functions may be revealed. The identification of viable mutations in this essential protein may help define the range of activity and interactions needed. All of this information provides opportunities to fine-tune existing therapies based on homologous recombination status, guide diagnosis, and hopefully develop new clinical tools.
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Affiliation(s)
- Nick Ll van der Zon
- Department of Molecular Genetics, Erasmus MC, Rotterdam, PO Box 2040, 3000 CA, The Netherlands
| | - Roland Kanaar
- Department of Molecular Genetics, Erasmus MC, Rotterdam, PO Box 2040, 3000 CA, The Netherlands.,Oncode Institute, Erasmus MC, Rotterdam, PO Box 2040, 3000 CA, The Netherlands
| | - Claire Wyman
- Department of Molecular Genetics, Erasmus MC, Rotterdam, PO Box 2040, 3000 CA, The Netherlands.,Department of Radiation Oncology, Erasmus MC, Rotterdam, PO Box 2040, 3000 CA, The Netherlands
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18
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van der Zon NLL, Kanaar R, Wyman C. Variation in RAD51 details a hub of functions: opportunities to advance cancer diagnosis and therapy. F1000Res 2018; 7:F1000 Faculty Rev-1453. [PMID: 30271574 PMCID: PMC6137408 DOI: 10.12688/f1000research.15650.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/29/2018] [Indexed: 11/06/2023] Open
Abstract
Loss of genome stability is one of the hallmarks of the enabling characteristics of cancer development. Homologous recombination is a DNA repair process that often breaks down as a prelude to developing cancer. Conversely, homologous recombination can be the Achilles' heel in common anti-cancer therapies, which are effective by inducing irreparable DNA damage. Here, we review recent structural and functional studies of RAD51, the protein that catalyzes the defining step of homologous recombination: homology recognition and DNA strand exchange. Specific mutations can be linked to structural changes and known essential functions. Additional RAD51 interactions and functions may be revealed. The identification of viable mutations in this essential protein may help define the range of activity and interactions needed. All of this information provides opportunities to fine-tune existing therapies based on homologous recombination status, guide diagnosis, and hopefully develop new clinical tools.
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Affiliation(s)
- Nick LL van der Zon
- Department of Molecular Genetics, Erasmus MC, Rotterdam, PO Box 2040, 3000 CA, The Netherlands
| | - Roland Kanaar
- Department of Molecular Genetics, Erasmus MC, Rotterdam, PO Box 2040, 3000 CA, The Netherlands
- Oncode Institute, Erasmus MC, Rotterdam, PO Box 2040, 3000 CA, The Netherlands
| | - Claire Wyman
- Department of Molecular Genetics, Erasmus MC, Rotterdam, PO Box 2040, 3000 CA, The Netherlands
- Department of Radiation Oncology, Erasmus MC, Rotterdam, PO Box 2040, 3000 CA, The Netherlands
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19
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Li Q, Gakhar L, Ashley Spies M. Determinants of human glucokinase activation and implications for small molecule allosteric control. Biochim Biophys Acta Gen Subj 2018; 1862:1902-1912. [PMID: 29885360 DOI: 10.1016/j.bbagen.2018.06.001] [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: 04/05/2018] [Revised: 05/31/2018] [Accepted: 06/04/2018] [Indexed: 11/26/2022]
Abstract
Glucokinase (GK) is an enzyme that catalyzes the ATP-dependent phosphorylation of glucose to form glucose-6-phosphate, and it is a tightly regulated checkpoint in glucose homeostasis. GK is known to undergo substantial conformational changes upon glucose binding. The monomeric enzyme possesses a highly exotic kinetic activity profile with an unusual sigmoidal dependence on glucose concentration. In this interdisciplinary study, which draws on small angle X-ray scattering (SAXS) integrated with 250 ns of atomistic molecular dynamics (MD) simulations and experimental glucose binding thermodynamics, we reveal that the critical regulation of this glucose sensor is due to a solvent controlled "switch". We demonstrate that the "solvent switch" is driven by specific protein structural dynamics, which leads to an enzyme structure that has a much more favorable solvation energy than most of the protein ensemble. These findings uncover the physical workings of an agile and flexible protein scaffold, which derives its long-range allosteric control through specific regions with favorable solvation energy. The physiological framework presented herein provides insights that have direct implications for the design of small molecule GK activators as anti-diabetes therapeutics as well as for understanding how proteins can be designed to have built-in regulatory functions via solvation energy dynamics.
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Affiliation(s)
- Quinn Li
- Department of Biochemistry, The University of Iowa, Iowa City, IA 52242, United States
| | - Lokesh Gakhar
- Department of Biochemistry, The University of Iowa, Iowa City, IA 52242, United States; Protein Crystallography Facility, The University of Iowa, Iowa City, IA 52242, United States
| | - M Ashley Spies
- Department of Biochemistry, The University of Iowa, Iowa City, IA 52242, United States; Department of Medicinal Natural Products Chemistry, The University of Iowa, Iowa City, IA 52242, United States.
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20
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Li Q, Folly da Silva Constantino L, Spies MA. Integrating Experimental and In Silico HTS in the Discovery of Inhibitors of Protein-Nucleic Acid Interactions. Methods Enzymol 2018. [PMID: 29523234 DOI: 10.1016/bs.mie.2017.11.036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Discovery of novel tool compounds and drug leads against a range of unorthodox protein targets has pushed both experimental screening methodologies as well as the field of structure-based design to the limit in recent years. Increasingly, it has been recognized that some of the most desirable targets for the development of small-molecule effectors are actually protein-protein and protein-nucleic acid interactions. There are numerous nontrivial challenges to pursuing small-molecule lead compounds directed toward PPIs and PNIs: relatively shallow cavities, large surface areas that are natively complexed to macromolecules, complex patterns of interstitial waters, a paucity of "hot spots," large conformational changes upon ligand binding, etc. Although there have been some notable successes targeting PPIs in the last decade, there has been distinctly less success in the realm of targeting PNIs. This chapter focuses on an approach, successfully applied by our group to address the challenge of gaining traction on the PPI target RAD52, which is a protein that binds both single-stranded and double-stranded DNA, and is an anticancer target for certain types of cancer. There are many approaches to tackling the difficult problems of finding effective small molecules that disrupt PPIs and PNIs, but the methods presented here offer a series of elegant solutions, which integrate experimental HTS, biophysical methods, docking, and molecular dynamics in a powerful way. Additionally, the structural knowledge gained from these studies provides a means for rationally understanding what features lead to ligand affinity in these fascinating and highly unorthodox pockets.
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Affiliation(s)
- Quinn Li
- The University of Iowa, Iowa City, IA, United States
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21
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Abstract
The RAD51 DNA strand exchange protein plays an important role in maintaining the integrity of the human genome. It promotes homology-directed DNA repair by exchanging strands between the damaged and the intact DNA molecules. It also plays an important role in stabilizing distressed DNA replication forks. When overexpressed or misregulated, however, RAD51 contributes to "rogue," genome destabilizing events that can lead to cancer, cell death, and to acquisition of chemotherapy resistance by cancerous cells. Human RAD51 is, therefore, an important and highly coveted anticancer drug target. Biochemical, biophysical, and structural studies of the human RAD51 and establishment of its structure-activity relationship require purification of large quantities of protein. In this chapter we describe a robust method for expression and purification of human RAD51 and the methods for assessing its activity based on the single-strand DNA-binding stoichiometry and its capacity to carry out the DNA strand exchange reaction.
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22
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Abstract
Human RAD51 promotes accurate DNA repair by homologous recombination and is involved in protection and repair of damaged DNA replication forks. The active species of RAD51 and related recombinases in all organisms is a nucleoprotein filament assembled on single-stranded DNA (ssDNA). The formation of a nucleoprotein filament competent for the recombination reaction, or for DNA replication support, is a delicate and strictly regulated process, which occurs through filament nucleation followed by filament extension. The rates of these two phases of filament formation define the capacity of RAD51 to compete with the ssDNA-binding protein RPA, as well as the lengths of the resulting filament segments. Single-molecule approaches can provide a wealth of quantitative information on the kinetics of RAD51 nucleoprotein filament assembly, internal dynamics, and disassembly. In this chapter, we describe how to set up a single-molecule total internal reflection fluorescence microscopy experiment to monitor the initial steps of RAD51 nucleoprotein filament formation in real-time and at single-monomer resolution. This approach is based on the unique, stretched-ssDNA conformation within the recombinase nucleoprotein filament and follows the efficiency of Förster resonance energy transfer (EFRET) between two DNA-conjugated fluorophores. We will discuss the practical aspects of the experimental setup, extraction of the FRET trajectories, and how to analyze and interpret the data to obtain information on RAD51 nucleation kinetics, the mechanism of nucleation, and the oligomeric species involved in filament formation.
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23
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Hengel SR, Spies MA, Spies M. Small-Molecule Inhibitors Targeting DNA Repair and DNA Repair Deficiency in Research and Cancer Therapy. Cell Chem Biol 2017; 24:1101-1119. [PMID: 28938088 PMCID: PMC5679738 DOI: 10.1016/j.chembiol.2017.08.027] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 08/11/2017] [Accepted: 08/30/2017] [Indexed: 01/13/2023]
Abstract
To maintain stable genomes and to avoid cancer and aging, cells need to repair a multitude of deleterious DNA lesions, which arise constantly in every cell. Processes that support genome integrity in normal cells, however, allow cancer cells to develop resistance to radiation and DNA-damaging chemotherapeutics. Chemical inhibition of the key DNA repair proteins and pharmacologically induced synthetic lethality have become instrumental in both dissecting the complex DNA repair networks and as promising anticancer agents. The difficulty in capitalizing on synthetically lethal interactions in cancer cells is that many potential targets do not possess well-defined small-molecule binding determinates. In this review, we discuss several successful campaigns to identify and leverage small-molecule inhibitors of the DNA repair proteins, from PARP1, a paradigm case for clinically successful small-molecule inhibitors, to coveted new targets, such as RAD51 recombinase, RAD52 DNA repair protein, MRE11 nuclease, and WRN DNA helicase.
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Affiliation(s)
- Sarah R Hengel
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
| | - M Ashley Spies
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA; Department of Pharmaceutical Sciences and Experimental Therapeutics, Division of Medicinal and Natural Products Chemistry, University of Iowa, Iowa City, IA 52242, USA.
| | - Maria Spies
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA.
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24
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Fujii N. Potential Strategies to Target Protein-Protein Interactions in the DNA Damage Response and Repair Pathways. J Med Chem 2017; 60:9932-9959. [PMID: 28654754 DOI: 10.1021/acs.jmedchem.7b00358] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
This review article discusses some insights about generating novel mechanistic inhibitors of the DNA damage response and repair (DDR) pathways by focusing on protein-protein interactions (PPIs) of the key DDR components. General requirements for PPI strategies, such as selecting the target PPI site on the basis of its functionality, are discussed first. Next, on the basis of functional rationale and biochemical feasibility to identify a PPI inhibitor, 26 PPIs in DDR pathways (BER, MMR, NER, NHEJ, HR, TLS, and ICL repair) are specifically discussed for inhibitor discovery to benefit cancer therapies using a DNA-damaging agent.
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Affiliation(s)
- Naoaki Fujii
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital , 262 Danny Thomas Place, MS1000, Memphis, Tennessee 38105, United States
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25
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Collonnier C, Guyon-Debast A, Maclot F, Mara K, Charlot F, Nogué F. Towards mastering CRISPR-induced gene knock-in in plants: Survey of key features and focus on the model Physcomitrella patens. Methods 2017; 121-122:103-117. [PMID: 28478103 DOI: 10.1016/j.ymeth.2017.04.024] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 04/10/2017] [Accepted: 04/21/2017] [Indexed: 10/19/2022] Open
Abstract
Beyond its predominant role in human and animal therapy, the CRISPR-Cas9 system has also become an essential tool for plant research and plant breeding. Agronomic applications rely on the mastery of gene inactivation and gene modification. However, if the knock-out of genes by non-homologous end-joining (NHEJ)-mediated repair of the targeted double-strand breaks (DSBs) induced by the CRISPR-Cas9 system is rather well mastered, the knock-in of genes by homology-driven repair or end-joining remains difficult to perform efficiently in higher plants. In this review, we describe the different approaches that can be tested to improve the efficiency of CRISPR-induced gene modification in plants, which include the use of optimal transformation and regeneration protocols, the design of appropriate guide RNAs and donor templates and the choice of nucleases and means of delivery. We also present what can be done to orient DNA repair pathways in the target cells, and we show how the moss Physcomitrella patens can be used as a model plant to better understand what DNA repair mechanisms are involved, and how this knowledge could eventually be used to define more performant strategies of CRISPR-induced gene knock-in.
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Affiliation(s)
- Cécile Collonnier
- INRA Centre de Versailles-Grignon, IJPB (UMR1318) - route de St-Cyr, 78026 Versailles cedex, France.
| | - Anouchka Guyon-Debast
- INRA Centre de Versailles-Grignon, IJPB (UMR1318) - route de St-Cyr, 78026 Versailles cedex, France
| | - François Maclot
- INRA Centre de Versailles-Grignon, IJPB (UMR1318) - route de St-Cyr, 78026 Versailles cedex, France
| | - Kostlend Mara
- INRA Centre de Versailles-Grignon, IJPB (UMR1318) - route de St-Cyr, 78026 Versailles cedex, France
| | - Florence Charlot
- INRA Centre de Versailles-Grignon, IJPB (UMR1318) - route de St-Cyr, 78026 Versailles cedex, France
| | - Fabien Nogué
- INRA Centre de Versailles-Grignon, IJPB (UMR1318) - route de St-Cyr, 78026 Versailles cedex, France.
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26
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Luo K, Li L, Li Y, Wu C, Yin Y, Chen Y, Deng M, Nowsheen S, Yuan J, Lou Z. A phosphorylation-deubiquitination cascade regulates the BRCA2-RAD51 axis in homologous recombination. Genes Dev 2016; 30:2581-2595. [PMID: 27941124 PMCID: PMC5204351 DOI: 10.1101/gad.289439.116] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 11/30/2016] [Indexed: 11/24/2022]
Abstract
Homologous recombination (HR) is one of the major DNA double-strand break (DSB) repair pathways in mammalian cells. Defects in HR trigger genomic instability and result in cancer predisposition. The defining step of HR is homologous strand exchange directed by the protein RAD51, which is recruited to DSBs by BRCA2. However, the regulation of the BRCA2-RAD51 axis remains unclear. Here we report that ubiquitination of RAD51 hinders RAD51-BRCA2 interaction, while deubiquitination of RAD51 facilitates RAD51-BRCA2 binding and RAD51 recruitment and thus is critical for proper HR. Mechanistically, in response to DNA damage, the deubiquitinase UCHL3 is phosphorylated and activated by ATM. UCHL3, in turn, deubiquitinates RAD51 and promotes the binding between RAD51 and BRCA2. Overexpression of UCHL3 renders breast cancer cells resistant to radiation and chemotherapy, while depletion of UCHL3 sensitizes cells to these treatments, suggesting a determinant role of UCHL3 in cancer therapy. Overall, we identify UCHL3 as a novel regulator of DNA repair and reveal a model in which a phosphorylation-deubiquitination cascade dynamically regulates the BRCA2-RAD51 pathway.
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Affiliation(s)
- Kuntian Luo
- Research Center for Translational Medicine, East Hospital, Tongji University School of Medicine, Shanghai 200120, China.,Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai 200120, China.,Department of Oncology, Mayo Clinic, Rochester, Minnesota 55905, USA
| | - Lei Li
- Research Center for Translational Medicine, East Hospital, Tongji University School of Medicine, Shanghai 200120, China.,Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai 200120, China
| | - Yunhui Li
- Research Center for Translational Medicine, East Hospital, Tongji University School of Medicine, Shanghai 200120, China.,Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai 200120, China
| | - Chenming Wu
- Research Center for Translational Medicine, East Hospital, Tongji University School of Medicine, Shanghai 200120, China.,Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai 200120, China
| | - Yujiao Yin
- Research Center for Translational Medicine, East Hospital, Tongji University School of Medicine, Shanghai 200120, China.,Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai 200120, China
| | - Yuping Chen
- Research Center for Translational Medicine, East Hospital, Tongji University School of Medicine, Shanghai 200120, China.,Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai 200120, China
| | - Min Deng
- Department of Oncology, Mayo Clinic, Rochester, Minnesota 55905, USA
| | - Somaira Nowsheen
- Medical Scientist Training Program, Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic School of Medicine, Rochester, Minnesota 55905, USA
| | - Jian Yuan
- Research Center for Translational Medicine, East Hospital, Tongji University School of Medicine, Shanghai 200120, China.,Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai 200120, China.,Department of Oncology, Mayo Clinic, Rochester, Minnesota 55905, USA
| | - Zhenkun Lou
- Department of Oncology, Mayo Clinic, Rochester, Minnesota 55905, USA.,Beijing Proteome Research Center, Beijing Institute of Radiation Medicine, Beijing 100850, China
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27
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Moschetti T, Sharpe T, Fischer G, Marsh ME, Ng HK, Morgan M, Scott DE, Blundell TL, R. Venkitaraman A, Skidmore J, Abell C, Hyvönen M. Engineering Archeal Surrogate Systems for the Development of Protein-Protein Interaction Inhibitors against Human RAD51. J Mol Biol 2016; 428:4589-4607. [PMID: 27725183 PMCID: PMC5117717 DOI: 10.1016/j.jmb.2016.10.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2016] [Revised: 10/02/2016] [Accepted: 10/04/2016] [Indexed: 02/02/2023]
Abstract
Protein-protein interactions (PPIs) are increasingly important targets for drug discovery. Efficient fragment-based drug discovery approaches to tackle PPIs are often stymied by difficulties in the production of stable, unliganded target proteins. Here, we report an approach that exploits protein engineering to "humanise" thermophilic archeal surrogate proteins as targets for small-molecule inhibitor discovery and to exemplify this approach in the development of inhibitors against the PPI between the recombinase RAD51 and tumour suppressor BRCA2. As human RAD51 has proved impossible to produce in a form that is compatible with the requirements of fragment-based drug discovery, we have developed a surrogate protein system using RadA from Pyrococcus furiosus. Using a monomerised RadA as our starting point, we have adopted two parallel and mutually instructive approaches to mimic the human enzyme: firstly by mutating RadA to increase sequence identity with RAD51 in the BRC repeat binding sites, and secondly by generating a chimeric archaeal human protein. Both approaches generate proteins that interact with a fourth BRC repeat with affinity and stoichiometry comparable to human RAD51. Stepwise humanisation has also allowed us to elucidate the determinants of RAD51 binding to BRC repeats and the contributions of key interacting residues to this interaction. These surrogate proteins have enabled the development of biochemical and biophysical assays in our ongoing fragment-based small-molecule inhibitor programme and they have allowed us to determine hundreds of liganded structures in support of our structure-guided design process, demonstrating the feasibility and advantages of using archeal surrogates to overcome difficulties in handling human proteins.
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Affiliation(s)
- Tommaso Moschetti
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, UK
| | - Timothy Sharpe
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, UK
| | - Gerhard Fischer
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, UK
| | - May E. Marsh
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, UK
| | - Hong Kin Ng
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, UK
| | - Matthew Morgan
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, UK
| | - Duncan E. Scott
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Tom L. Blundell
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, UK
| | - Ashok R. Venkitaraman
- Medical Research Council Cancer Unit, University of Cambridge, Hills Road, Cambridge CB2 0XZ, UK
| | - John Skidmore
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Chris Abell
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Marko Hyvönen
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, UK,Corresponding author.
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28
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Tyrosine phosphorylation stimulates activity of human RAD51 recombinase through altered nucleoprotein filament dynamics. Proc Natl Acad Sci U S A 2016; 113:E6045-E6054. [PMID: 27671650 DOI: 10.1073/pnas.1604807113] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The DNA strand exchange protein RAD51 facilitates the central step in homologous recombination, a process fundamentally important for accurate repair of damaged chromosomes, restart of collapsed replication forks, and telomere maintenance. The active form of RAD51 is a nucleoprotein filament that assembles on single-stranded DNA (ssDNA) at the sites of DNA damage. The c-Abl tyrosine kinase and its oncogenic counterpart BCR-ABL fusion kinase phosphorylate human RAD51 on tyrosine residues 54 and 315. We combined biochemical reconstitutions of the DNA strand exchange reactions with total internal reflection fluorescence microscopy to determine how the two phosphorylation events affect the biochemical activities of human RAD51 and properties of the RAD51 nucleoprotein filament. By mimicking RAD51 tyrosine phosphorylation with a nonnatural amino acid, p-carboxymethyl-l-phenylalanine (pCMF), we demonstrated that Y54 phosphorylation enhances the RAD51 recombinase activity by at least two different mechanisms, modifies the RAD51 nucleoprotein filament formation, and allows RAD51 to compete efficiently with ssDNA binding protein RPA. In contrast, Y315 phosphorylation has little effect on the RAD51 activities. Based on our work and previous cellular studies, we propose a mechanism underlying RAD51 activation by c-Abl/BCR-ABL kinases.
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29
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Short JM, Liu Y, Chen S, Soni N, Madhusudhan MS, Shivji MKK, Venkitaraman AR. High-resolution structure of the presynaptic RAD51 filament on single-stranded DNA by electron cryo-microscopy. Nucleic Acids Res 2016; 44:9017-9030. [PMID: 27596592 PMCID: PMC5100573 DOI: 10.1093/nar/gkw783] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 08/24/2016] [Indexed: 12/21/2022] Open
Abstract
Homologous DNA recombination (HR) by the RAD51 recombinase enables error-free DNA break repair. To execute HR, RAD51 first forms a presynaptic filament on single-stranded (ss) DNA, which catalyses pairing with homologous double-stranded (ds) DNA. Here, we report a structure for the presynaptic human RAD51 filament at 3.5–5.0Å resolution using electron cryo-microscopy. RAD51 encases ssDNA in a helical filament of 103Å pitch, comprising 6.4 protomers per turn, with a rise of 16.1Å and a twist of 56.2°. Inter-protomer distance correlates with rotation of an α-helical region in the core catalytic domain that is juxtaposed to ssDNA, suggesting how the RAD51–DNA interaction modulates protomer spacing and filament pitch. We map Fanconi anaemia-like disease-associated RAD51 mutations, clarifying potential phenotypes. We predict binding sites on the presynaptic filament for two modules present in each BRC repeat of the BRCA2 tumour suppressor, a critical HR mediator. Structural modelling suggests that changes in filament pitch mask or expose one binding site with filament-inhibitory potential, rationalizing the paradoxical ability of the BRC repeats to either stabilize or inhibit filament formation at different steps during HR. Collectively, our findings provide fresh insight into the structural mechanism of HR and its dysregulation in human disease.
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Affiliation(s)
- Judith M Short
- Medical Research Council Cancer Unit, University of Cambridge, Hills Road, Cambridge CB2 0XZ, UK
| | - Yang Liu
- Medical Research Council Cancer Unit, University of Cambridge, Hills Road, Cambridge CB2 0XZ, UK
| | - Shaoxia Chen
- Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Neelesh Soni
- Indian Institute of Science, Education & Research, Dr Homi Babha Road, Pune 411 008, India
| | - Mallur S Madhusudhan
- Indian Institute of Science, Education & Research, Dr Homi Babha Road, Pune 411 008, India.,Bioinformatics Institute, A*STAR, 30 Biopolis Drive, 138671 Singapore
| | - Mahmud K K Shivji
- Medical Research Council Cancer Unit, University of Cambridge, Hills Road, Cambridge CB2 0XZ, UK
| | - Ashok R Venkitaraman
- Medical Research Council Cancer Unit, University of Cambridge, Hills Road, Cambridge CB2 0XZ, UK
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30
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Chen R, Subramanyam S, Elcock AH, Spies M, Wold MS. Dynamic binding of replication protein a is required for DNA repair. Nucleic Acids Res 2016; 44:5758-72. [PMID: 27131385 PMCID: PMC4937323 DOI: 10.1093/nar/gkw339] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 04/15/2016] [Indexed: 12/14/2022] Open
Abstract
Replication protein A (RPA), the major eukaryotic single-stranded DNA (ssDNA) binding protein, is essential for replication, repair and recombination. High-affinity ssDNA-binding by RPA depends on two DNA binding domains in the large subunit of RPA. Mutation of the evolutionarily conserved aromatic residues in these two domains results in a separation-of-function phenotype: aromatic residue mutants support DNA replication but are defective in DNA repair. We used biochemical and single-molecule analyses, and Brownian Dynamics simulations to determine the molecular basis of this phenotype. Our studies demonstrated that RPA binds to ssDNA in at least two modes characterized by different dissociation kinetics. We also showed that the aromatic residues contribute to the formation of the longer-lived state, are required for stable binding to short ssDNA regions and are needed for RPA melting of partially duplex DNA structures. We conclude that stable binding and/or the melting of secondary DNA structures by RPA is required for DNA repair, including RAD51 mediated DNA strand exchange, but is dispensable for DNA replication. It is likely that the binding modes are in equilibrium and reflect dynamics in the RPA-DNA complex. This suggests that dynamic binding of RPA to DNA is necessary for different cellular functions.
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Affiliation(s)
- Ran Chen
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Shyamal Subramanyam
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Adrian H Elcock
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Maria Spies
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Marc S Wold
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
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31
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Yang Q, Nair S, Laknaur A, Ismail N, Diamond MP, Al-Hendy A. The Polycomb Group Protein EZH2 Impairs DNA Damage Repair Gene Expression in Human Uterine Fibroids. Biol Reprod 2016; 94:69. [PMID: 26888970 PMCID: PMC4829092 DOI: 10.1095/biolreprod.115.134924] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 02/03/2016] [Indexed: 12/17/2022] Open
Abstract
Uterine fibroids are benign, smooth muscle tumors that occur in approximately 70%-80% of women by age 50 yr. The cellular and molecular mechanism(s) by which uterine fibroids (UFs) develop are not fully understood. Accumulating evidence demonstrates that several genetic abnormalities, including deletions, rearrangements, translocations, as well as mutations, have been found in UFs. These genetic anomalies suggest that low DNA damage repair capacity may be involved in UF formation. The objective of this study was to determine whether expression levels of DNA damage repair-related genes were altered, and how they were regulated in the pathogenesis of UFs. Expression levels of DNA repair-related genes RAD51 and BRCA1 were deregulated in fibroid tissues as compared to adjacent myometrial tissues. Expression levels of chromatin protein enhancer of zeste homolog 2 (EZH2) were higher in a subset of fibroids as compared to adjacent myometrial tissues by both immunohistochemistry and Western blot analysis. Treatment with an inhibitor of EZH2 markedly increased expression levels of RAD51 and BRCA1 in fibroid cells and inhibited cell proliferation paired with cell cycle arrest. Restoring the expression of RAD51 and BRCA1 by treatment with EZH2 inhibitor was dependent on reducing the enrichment of trimethylation of histone 3 lysine 27 epigenetic mark in their promoter regions. This study reveals the important role of EZH2-regulated DNA damage-repair genes via histone methylation in fibroid biology, and may provide novel therapeutic targets for the medical treatment of women with symptomatic UFs.
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Affiliation(s)
- Qiwei Yang
- Division of Translation Research, Department of Obstetrics and Gynecology, Augusta University, Medical College of Georgia, Augusta, Georgia
| | - Sangeeta Nair
- Division of Translation Research, Department of Obstetrics and Gynecology, Augusta University, Medical College of Georgia, Augusta, Georgia
| | - Archana Laknaur
- Division of Translation Research, Department of Obstetrics and Gynecology, Augusta University, Medical College of Georgia, Augusta, Georgia
| | - Nahed Ismail
- Clinical Microbiology Division, Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Michael P Diamond
- Division of Translation Research, Department of Obstetrics and Gynecology, Augusta University, Medical College of Georgia, Augusta, Georgia
| | - Ayman Al-Hendy
- Division of Translation Research, Department of Obstetrics and Gynecology, Augusta University, Medical College of Georgia, Augusta, Georgia
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32
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FBH1 influences DNA replication fork stability and homologous recombination through ubiquitylation of RAD51. Nat Commun 2015; 6:5931. [PMID: 25585578 DOI: 10.1038/ncomms6931] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Accepted: 11/19/2014] [Indexed: 11/09/2022] Open
Abstract
Unscheduled homologous recombination (HR) can lead to genomic instability, which greatly increases the threat of neoplastic transformation in humans. The F-box DNA helicase 1 (FBH1) is a 3'-5' DNA helicase with a putative function as a negative regulator of HR. It is the only known DNA helicase to contain an F-box, suggesting that one of its functions is to act as a ubiquitin ligase as part of an SCF (SKP1, CUL1 and F-box) complex. Here we report that the central player in HR, RAD51, is ubiquitylated by the SCF(FBH1) complex. Expression of an ubiquitylation-resistant form of RAD51 in human cells leads to hyperrecombination, as well as several phenotypes indicative of an altered response to DNA replication stress. These effects are likely to be mediated by the enhanced nuclear matrix association of the ubiquitylation-resistant RAD51. These data are consistent with FBH1 acting as a negative regulator of RAD51 function in human cells.
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33
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Kirsch R, Gramzow L, Theißen G, Siegfried BD, Ffrench-Constant RH, Heckel DG, Pauchet Y. Horizontal gene transfer and functional diversification of plant cell wall degrading polygalacturonases: Key events in the evolution of herbivory in beetles. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2014; 52:33-50. [PMID: 24978610 DOI: 10.1016/j.ibmb.2014.06.008] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 06/12/2014] [Accepted: 06/19/2014] [Indexed: 05/26/2023]
Abstract
Plant cell walls are the largest reservoir of organic carbon on earth. To breach and utilize this carbohydrate-rich protective barrier, microbes secrete plant cell wall degrading enzymes (PCWDEs) targeting pectin, cellulose and hemicelluloses. There is a growing body of evidence that genomes of some herbivorous insects also encode PCWDEs, raising questions about their evolutionary origins and functions. Among herbivorous beetles, pectin-degrading polygalacturonases (PGs) are found in the diverse superfamilies Chrysomeloidea (leaf beetles, long-horn beetles) and Curculionoidea (weevils). Here our aim was to test whether these arose from a common ancestor of beetles or via horizontal gene transfer (HGT), and whether PGs kept their ancestral function in degrading pectin or evolved novel functions. Transcriptome data derived from 10 beetle species were screened for PG-encoding sequences and used for phylogenetic comparisons with their bacterial, fungal and plant counterparts. These analyses revealed a large family of PG-encoding genes of Chrysomeloidea and Curculionoidea sharing a common ancestor, most similar to PG genes of ascomycete fungi. In addition, 50 PGs from beetle digestive systems were heterologously expressed and functionally characterized, showing a set of lineage-specific consecutively pectin-degrading enzymes, as well as conserved but enzymatically inactive PG proteins. The evidence indicates that a PG gene was horizontally transferred ∼200 million years ago from an ascomycete fungus to a common ancestor of Chrysomeloidea and Curculionoidea. This has been followed by independent duplications in these two lineages, as well as independent replacement in two sublineages of Chrysomeloidea by two other subsequent HGTs. This origin, leading to subsequent functional diversification of the PG gene family within its new hosts, was a key event promoting the evolution of herbivory in these beetles.
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Affiliation(s)
- Roy Kirsch
- Department of Entomology, Max Planck Institute for Chemical Ecology, Hans-Knoell-Str. 8, 07745 Jena, Germany.
| | - Lydia Gramzow
- Department of Genetics, Friedrich Schiller University Jena, Philosophenweg 12, 07743 Jena, Germany
| | - Günter Theißen
- Department of Genetics, Friedrich Schiller University Jena, Philosophenweg 12, 07743 Jena, Germany
| | - Blair D Siegfried
- Department of Entomology, University of Nebraska, 312A Entomology Hall, Lincoln, 68583-0816 NE, United States
| | | | - David G Heckel
- Department of Entomology, Max Planck Institute for Chemical Ecology, Hans-Knoell-Str. 8, 07745 Jena, Germany
| | - Yannick Pauchet
- Department of Entomology, Max Planck Institute for Chemical Ecology, Hans-Knoell-Str. 8, 07745 Jena, Germany.
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