1
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Petiot V, White CI, Da Ines O. DNA-binding site II is required for RAD51 recombinogenic activity in Arabidopsis thaliana. Life Sci Alliance 2024; 7:e202402701. [PMID: 38803223 PMCID: PMC11106524 DOI: 10.26508/lsa.202402701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Revised: 05/03/2024] [Accepted: 05/07/2024] [Indexed: 05/29/2024] Open
Abstract
Homologous recombination is a major pathway for the repair of DNA double strand breaks, essential both to maintain genomic integrity and to generate genetic diversity. Mechanistically, homologous recombination involves the use of a homologous DNA molecule as a template to repair the break. In eukaryotes, the search for and invasion of the homologous DNA molecule is carried out by two recombinases, RAD51 in somatic cells and RAD51 and DMC1 in meiotic cells. During recombination, the recombinases bind overhanging single-stranded DNA ends to form a nucleoprotein filament, which is the active species in promoting DNA invasion and strand exchange. RAD51 and DMC1 carry two major DNA-binding sites-essential for nucleofilament formation and DNA strand exchange, respectively. Here, we show that the function of RAD51 DNA-binding site II is conserved in the plant, Arabidopsis. Mutation of three key amino acids in site II does not affect RAD51 nucleofilament formation but inhibits its recombinogenic activity, analogous to results from studies of the yeast and human proteins. We further confirm that recombinogenic function of RAD51 DNA-binding site II is not required for meiotic double-strand break repair when DMC1 is present. The Arabidopsis AtRAD51-II3A separation of function mutant shows a dominant negative phenotype, pointing to distinct biochemical properties of eukaryotic RAD51 proteins.
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Affiliation(s)
- Valentine Petiot
- https://ror.org/052d1cv78 Institut Génétique, Reproduction et Développement (iGReD), CNRS UMR 6293, INSERM U1103, Université Clermont Auvergne, Clermont-Ferrand, France
| | - Charles I White
- https://ror.org/052d1cv78 Institut Génétique, Reproduction et Développement (iGReD), CNRS UMR 6293, INSERM U1103, Université Clermont Auvergne, Clermont-Ferrand, France
| | - Olivier Da Ines
- https://ror.org/052d1cv78 Institut Génétique, Reproduction et Développement (iGReD), CNRS UMR 6293, INSERM U1103, Université Clermont Auvergne, Clermont-Ferrand, France
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2
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Takahashi M, Ito K, Iwasaki H, Norden B. Linear dichroism reveals the perpendicular orientation of DNA bases in the RecA and Rad51 recombinase filaments: A possible mechanism for the strand exchange reaction. Chirality 2024; 36:e23664. [PMID: 38561319 DOI: 10.1002/chir.23664] [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: 01/31/2024] [Revised: 02/26/2024] [Accepted: 03/06/2024] [Indexed: 04/04/2024]
Abstract
Linear dichroism spectroscopy is used to investigate the structure of RecA family recombinase filaments (RecA and Rad51 proteins) with DNA for clarifying the molecular mechanism of DNA strand exchange promoted by these proteins and its activation. The measurements show that the recombinases promote the perpendicular base orientation of single-stranded DNA only in the presence of activators, indicating the importance of base orientation in the reaction. We summarize the results and discuss the role of DNA base orientation.
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Affiliation(s)
- Masayuki Takahashi
- School of Life Science and Technology, Tokyo Institute of Technology, Tokyo, Japan
| | - Kentaro Ito
- Graduate School of Medical Life Science, Yokohama City University, Yokohama, Japan
| | - Hiroshi Iwasaki
- School of Life Science and Technology, Tokyo Institute of Technology, Tokyo, Japan
- Innovative Science Institute, Tokyo Institute of Technology, Yokohama, Japan
| | - Bengt Norden
- Department of Chemical and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
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3
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Shioi T, Hatazawa S, Oya E, Hosoya N, Kobayashi W, Ogasawara M, Kobayashi T, Takizawa Y, Kurumizaka H. Cryo-EM structures of RAD51 assembled on nucleosomes containing a DSB site. Nature 2024; 628:212-220. [PMID: 38509361 PMCID: PMC10990931 DOI: 10.1038/s41586-024-07196-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2023] [Accepted: 02/13/2024] [Indexed: 03/22/2024]
Abstract
RAD51 is the central eukaryotic recombinase required for meiotic recombination and mitotic repair of double-strand DNA breaks (DSBs)1,2. However, the mechanism by which RAD51 functions at DSB sites in chromatin has remained elusive. Here we report the cryo-electron microscopy structures of human RAD51-nucleosome complexes, in which RAD51 forms ring and filament conformations. In the ring forms, the N-terminal lobe domains (NLDs) of RAD51 protomers are aligned on the outside of the RAD51 ring, and directly bind to the nucleosomal DNA. The nucleosomal linker DNA that contains the DSB site is recognized by the L1 and L2 loops-active centres that face the central hole of the RAD51 ring. In the filament form, the nucleosomal DNA is peeled by the RAD51 filament extension, and the NLDs of RAD51 protomers proximal to the nucleosome bind to the remaining nucleosomal DNA and histones. Mutations that affect nucleosome-binding residues of the RAD51 NLD decrease nucleosome binding, but barely affect DNA binding in vitro. Consistently, yeast Rad51 mutants with the corresponding mutations are substantially defective in DNA repair in vivo. These results reveal an unexpected function of the RAD51 NLD, and explain the mechanism by which RAD51 associates with nucleosomes, recognizes DSBs and forms the active filament in chromatin.
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Affiliation(s)
- Takuro Shioi
- Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, Tokyo, Japan
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Suguru Hatazawa
- Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, Tokyo, Japan
| | - Eriko Oya
- Laboratory of Genome Regeneration, Institute for Quantitative Biosciences, The University of Tokyo, Tokyo, Japan
| | - Noriko Hosoya
- Laboratory of Molecular Radiology, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Wataru Kobayashi
- Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, Tokyo, Japan
| | - Mitsuo Ogasawara
- Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, Tokyo, Japan
| | - Takehiko Kobayashi
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
- Laboratory of Genome Regeneration, Institute for Quantitative Biosciences, The University of Tokyo, Tokyo, Japan
| | - Yoshimasa Takizawa
- Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, Tokyo, Japan
| | - Hitoshi Kurumizaka
- Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, Tokyo, Japan.
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan.
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4
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Renodon-Corniere A, Mikawa T, Kuwabara N, Ito K, Levitsky D, Iwasaki H, Takahashi M. Human Rad51 Protein Requires Higher Concentrations of Calcium Ions for D-Loop Formation than for Oligonucleotide Strand Exchange. Int J Mol Sci 2024; 25:3633. [PMID: 38612444 PMCID: PMC11011376 DOI: 10.3390/ijms25073633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2024] [Revised: 03/20/2024] [Accepted: 03/21/2024] [Indexed: 04/14/2024] Open
Abstract
Human Rad51 protein (HsRad51)-promoted DNA strand exchange, a crucial step in homologous recombination, is regulated by proteins and calcium ions. Both the activator protein Swi5/Sfr1 and Ca2+ ions stimulate different reaction steps and induce perpendicular DNA base alignment in the presynaptic complex. To investigate the role of base orientation in the strand exchange reaction, we examined the Ca2+ concentration dependence of strand exchange activities and structural changes in the presynaptic complex. Our results show that optimal D-loop formation (strand exchange with closed circular DNA) required Ca2+ concentrations greater than 5 mM, whereas 1 mM Ca2+ was sufficient for strand exchange between two oligonucleotides. Structural changes indicated by increased fluorescence intensity of poly(dεA) (a poly(dA) analog) reached a plateau at 1 mM Ca2+. Ca2+ > 2 mM was required for saturation of linear dichroism signal intensity at 260 nm, associated with rigid perpendicular DNA base orientation, suggesting a correlation with the stimulation of D-loop formation. Therefore, Ca2+ exerts two different effects. Thermal stability measurements suggest that HsRad51 binds two Ca2+ ions with KD values of 0.2 and 2.5 mM, implying that one step is stimulated by one Ca2+ bond and the other by two Ca2+ bonds. Our results indicate parallels between the Mg2+ activation of RecA and the Ca2+ activation of HsRad51.
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Affiliation(s)
| | - Tsutomu Mikawa
- RIKEN Center for Biosystems Dynamics Research, Yokohama 230-0045, Japan;
| | - Naoyuki Kuwabara
- Structural Biology Research Center, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Tsukuba 305-0801, Japan;
| | - Kentaro Ito
- Graduate School of Medical Life Science, Yokohama City University, Yokohama 230-0045, Japan;
| | - Dmitri Levitsky
- Nantes Université, CNRS, US2B, UMR 6286, F-44000 Nantes, France; (A.R.-C.); (D.L.)
| | - Hiroshi Iwasaki
- School of Life Science and Technology, Tokyo Institute of Technology, Tokyo 152-8550, Japan;
- Innovative Science Institute, Tokyo Institute of Technology, Yokohama 226-8503, Japan
| | - Masayuki Takahashi
- School of Life Science and Technology, Tokyo Institute of Technology, Tokyo 152-8550, Japan;
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5
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Emmenecker C, Mézard C, Kumar R. Repair of DNA double-strand breaks in plant meiosis: role of eukaryotic RecA recombinases and their modulators. PLANT REPRODUCTION 2023; 36:17-41. [PMID: 35641832 DOI: 10.1007/s00497-022-00443-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 05/09/2022] [Indexed: 06/15/2023]
Abstract
Homologous recombination during meiosis is crucial for the DNA double-strand breaks (DSBs) repair that promotes the balanced segregation of homologous chromosomes and enhances genetic variation. In most eukaryotes, two recombinases RAD51 and DMC1 form nucleoprotein filaments on single-stranded DNA generated at DSB sites and play a central role in the meiotic DSB repair and genome stability. These nucleoprotein filaments perform homology search and DNA strand exchange to initiate repair using homologous template-directed sequences located elsewhere in the genome. Multiple factors can regulate the assembly, stability, and disassembly of RAD51 and DMC1 nucleoprotein filaments. In this review, we summarize the current understanding of the meiotic functions of RAD51 and DMC1 and the role of their positive and negative modulators. We discuss the current models and regulators of homology searches and strand exchange conserved during plant meiosis. Manipulation of these repair factors during plant meiosis also holds a great potential to accelerate plant breeding for crop improvements and productivity.
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Affiliation(s)
- Côme Emmenecker
- Institut Jean-Pierre Bourgin (IJPB), Université Paris-Saclay, INRAE, AgroParisTech, 78000, Versailles, France
- University of Paris-Sud, Université Paris-Saclay, 91405, Orsay, France
| | - Christine Mézard
- Institut Jean-Pierre Bourgin (IJPB), CNRS, Université Paris-Saclay, INRAE, AgroParisTech, 78000, Versailles, France.
| | - Rajeev Kumar
- Institut Jean-Pierre Bourgin (IJPB), Université Paris-Saclay, INRAE, AgroParisTech, 78000, Versailles, France.
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6
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ATPase Activity of Bacillus subtilis RecA Affects the Dynamic Formation of RecA Filaments at DNA Double Strand Breaks. mSphere 2022; 7:e0041222. [PMID: 36321831 PMCID: PMC9769622 DOI: 10.1128/msphere.00412-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
RecA plays a central role in DNA repair and is a main actor involved in homologous recombination (HR). In vivo, RecA forms filamentous structures termed "threads," which are essential for HR, but whose nature is still ill defined. We show that RecA from Bacillus subtilis having lower ATP binding activity can still form nucleoprotein filaments in vitro, features lower dsDNA binding activity, but still retains most of wild type RecA activity in vivo. Contrarily, loss of ATPase activity strongly reduced formation of nucleoprotein filaments in vitro, and effectivity to repair double strand breaks (DSBs) in vivo. In the presence of wild type RecA protein, additionally expressed RecA with lowered ATPbinding activity only moderately affected RecA dynamics, while loss of ATPase activity leads to a large reduction of the formation of threads, as well as of their dynamic changes observed in a seconds-scale. Single molecule tracking of RecA revealed incorporation of freely diffusing and nonspecifically DNA-bound molecules into threads upon induction of a single DSB. This change of dynamics was highly perturbed in the absence of ATPase activity, revealing that filamentous forms of RecA as well as their dynamics depend on ATPase activity. Based on the idea that ATPase activity of RecA is most important for DNA strand exchange activity, our data suggest that extension and retraction of threads due is to many local strand invasion events during the search for sequences homologous to the induced DNA break site. IMPORTANCE Single-strand (ss) DNA binding ATPase RecA is the central recombinase in homologous recombination, and therefore essential for DNA repair pathways involving DNA strand exchange reactions. In several bacterial, RecA forms filamentous structures along the long axis of cells after induction of double strand breaks (DSBs) in the chromosome. These striking assemblies likely reflect RecA/ssDNA nucleoprotein filaments, which can extend and remodel within a time frame of few minutes. We show that ATPase activity of RecA is pivotal for these dynamic rearrangements, which include recruitment of freely diffusing molecules into low-mobile molecules within filaments. Our data suggest that ssDNA binding- and unbinding reactions are at the heart of RecA dynamics that power the dynamics of subcellular filamentous assemblies, leading to strand exchange reactions over a distance of several micrometers.
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7
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Blay V, Gailiunaite S, Lee CY, Chang HY, Hupp T, Houston DR, Chi P. Comparison of ATP-binding pockets and discovery of homologous recombination inhibitors. Bioorg Med Chem 2022; 70:116923. [PMID: 35841829 DOI: 10.1016/j.bmc.2022.116923] [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: 04/27/2022] [Revised: 06/16/2022] [Accepted: 07/06/2022] [Indexed: 11/02/2022]
Abstract
The ATP binding sites of many enzymes are structurally related, which complicates their development as therapeutic targets. In this work, we explore a diverse set of ATPases and compare their ATP binding pockets using different strategies, including direct and indirect structural methods, in search of pockets attractive for drug discovery. We pursue different direct and indirect structural strategies, as well as ligandability assessments to help guide target selection. The analyses indicate human RAD51, an enzyme crucial in homologous recombination, as a promising, tractable target. Inhibition of RAD51 has shown promise in the treatment of certain cancers but more potent inhibitors are needed. Thus, we design compounds computationally against the ATP binding pocket of RAD51 with consideration of multiple criteria, including predicted specificity, drug-likeness, and toxicity. The molecules designed are evaluated experimentally using molecular and cell-based assays. Our results provide two novel hit compounds against RAD51 and illustrate a computational pipeline to design new inhibitors against ATPases.
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Affiliation(s)
- Vincent Blay
- Institute of Quantitative Biology, Biochemistry and Biotechnology, University of Edinburgh, Edinburgh, Scotland EH9 3BF, UK; Department of Microbiology and Environmental Toxicology, University of California at Santa Cruz, Santa Cruz, CA 95064, USA; Institute for Integrative Systems Biology (I2Sysbio), Universitat de València and Spanish Research Council (CSIC), 46980 Valencia, Spain.
| | - Saule Gailiunaite
- Institute of Quantitative Biology, Biochemistry and Biotechnology, University of Edinburgh, Edinburgh, Scotland EH9 3BF, UK
| | - Chih-Ying Lee
- Institute of Biochemical Sciences, National Taiwan University, Taipei 10617, Taiwan
| | - Hao-Yen Chang
- Institute of Biochemical Sciences, National Taiwan University, Taipei 10617, Taiwan
| | - Ted Hupp
- MRC Institute of Genetics & Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh, UK
| | - Douglas R Houston
- Institute of Quantitative Biology, Biochemistry and Biotechnology, University of Edinburgh, Edinburgh, Scotland EH9 3BF, UK.
| | - Peter Chi
- Institute of Biochemical Sciences, National Taiwan University, Taipei 10617, Taiwan; Institute of Biological Chemistry, Academia Sinica, Taipei 11529, Taiwan
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8
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Woodbury DJ, Whitt EC, Coffman RE. A review of TNP-ATP in protein binding studies: benefits and pitfalls. BIOPHYSICAL REPORTS 2021; 1:100012. [PMID: 36425312 PMCID: PMC9680771 DOI: 10.1016/j.bpr.2021.100012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Accepted: 08/03/2021] [Indexed: 06/16/2023]
Abstract
We review 50 years of use of 2',3'-O-trinitrophenyl (TNP)-ATP, a fluorescently tagged ATP analog. It has been extensively used to detect binding interactions of ATP to proteins and to measure parameters of those interactions such as the dissociation constant, Kd, or inhibitor dissociation constant, Ki. TNP-ATP has also found use in other applications, for example, as a fluorescence marker in microscopy, as a FRET pair, or as an antagonist (e.g., of P2X receptors). However, its use in protein binding studies has limitations because the TNP moiety often enhances binding affinity, and the fluorescence changes that occur with binding can be masked or mimicked in unexpected ways. The goal of this review is to provide a clear perspective of the pros and cons of using TNP-ATP to allow for better experimental design and less ambiguous data in future experiments using TNP-ATP and other TNP nucleotides.
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Affiliation(s)
- Dixon J. Woodbury
- Department of Cell Biology and Physiology
- Neuroscience Center, Brigham Young University, Provo, Utah
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9
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Muraszko J, Kramarz K, Argunhan B, Ito K, Baranowska G, Kurokawa Y, Murayama Y, Tsubouchi H, Lambert S, Iwasaki H, Dziadkowiec D. Rrp1 translocase and ubiquitin ligase activities restrict the genome destabilising effects of Rad51 in fission yeast. Nucleic Acids Res 2021; 49:6832-6848. [PMID: 34157114 PMCID: PMC8266636 DOI: 10.1093/nar/gkab511] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 05/27/2021] [Accepted: 06/06/2021] [Indexed: 11/20/2022] Open
Abstract
Rad51 is the key protein in homologous recombination that plays important roles during DNA replication and repair. Auxiliary factors regulate Rad51 activity to facilitate productive recombination, and prevent inappropriate, untimely or excessive events, which could lead to genome instability. Previous genetic analyses identified a function for Rrp1 (a member of the Rad5/16-like group of SWI2/SNF2 translocases) in modulating Rad51 function, shared with the Rad51 mediator Swi5-Sfr1 and the Srs2 anti-recombinase. Here, we show that Rrp1 overproduction alleviates the toxicity associated with excessive Rad51 levels in a manner dependent on Rrp1 ATPase domain. Purified Rrp1 binds to DNA and has a DNA-dependent ATPase activity. Importantly, Rrp1 directly interacts with Rad51 and removes it from double-stranded DNA, confirming that Rrp1 is a translocase capable of modulating Rad51 function. Rrp1 affects Rad51 binding at centromeres. Additionally, we demonstrate in vivo and in vitro that Rrp1 possesses E3 ubiquitin ligase activity with Rad51 as a substrate, suggesting that Rrp1 regulates Rad51 in a multi-tiered fashion.
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Affiliation(s)
| | - Karol Kramarz
- Institut Curie, Université PSL, CNRS UMR3348, 91400 Orsay, France.,Université Paris-Saclay, CNRS UMR3348, 91400 Orsay, France
| | - Bilge Argunhan
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Japan
| | - Kentaro Ito
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Japan
| | | | - Yumiko Kurokawa
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Japan
| | - Yasuto Murayama
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Japan
| | - Hideo Tsubouchi
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Japan
| | - Sarah Lambert
- Institut Curie, Université PSL, CNRS UMR3348, 91400 Orsay, France.,Université Paris-Saclay, CNRS UMR3348, 91400 Orsay, France
| | - Hiroshi Iwasaki
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Japan
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10
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Tsubouchi H, Argunhan B, Iwasaki H. Biochemical properties of fission yeast homologous recombination enzymes. Curr Opin Genet Dev 2021; 71:19-26. [PMID: 34246071 DOI: 10.1016/j.gde.2021.06.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 06/06/2021] [Accepted: 06/14/2021] [Indexed: 12/20/2022]
Abstract
Homologous recombination (HR) is a universal phenomenon conserved from viruses to humans. The mechanisms of HR are essentially the same in humans and simple unicellular eukaryotes like yeast. Two highly diverged yeast species, Saccharomyces cerevisiae and Schizosaccharomyces pombe, have proven exceptionally useful in understanding the fundamental mechanisms of eukaryotic HR by serving as a source for unique biological insights and also complementing each other. Here, we will review the features of S. pombe HR mechanisms in comparison to S. cerevisiae and other model organisms. Particular emphasis will be put on the biochemical characterization of HR mechanisms uncovered using S. pombe proteins.
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Affiliation(s)
- Hideo Tsubouchi
- Institute of Innovative Research, Tokyo Institute of Technology, Kanagawa, Japan; School of Life Science and Technology, Tokyo Institute of Technology, Kanagawa, Japan.
| | - Bilge Argunhan
- Institute of Innovative Research, Tokyo Institute of Technology, Kanagawa, Japan
| | - Hiroshi Iwasaki
- Institute of Innovative Research, Tokyo Institute of Technology, Kanagawa, Japan; School of Life Science and Technology, Tokyo Institute of Technology, Kanagawa, Japan.
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11
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Shkundina IS, Gall AA, Dick A, Cocklin S, Mazin AV. New RAD51 Inhibitors to Target Homologous Recombination in Human Cells. Genes (Basel) 2021; 12:genes12060920. [PMID: 34208492 PMCID: PMC8235719 DOI: 10.3390/genes12060920] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 06/10/2021] [Accepted: 06/11/2021] [Indexed: 12/31/2022] Open
Abstract
Targeting DNA repair proteins with small-molecule inhibitors became a proven anti-cancer strategy. Previously, we identified an inhibitor of a major protein of homologous recombination (HR) RAD51, named B02. B02 inhibited HR in human cells and sensitized them to chemotherapeutic drugs in vitro and in vivo. Here, using a medicinal chemistry approach, we aimed to improve the potency of B02. We identified the B02 analog, B02-isomer, which inhibits HR in human cells with significantly higher efficiency. We also show that B02-iso sensitizes triple-negative breast cancer MDA-MB-231 cells to the PARP inhibitor (PARPi) olaparib.
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Affiliation(s)
- Irina S. Shkundina
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, USA; (I.S.S.); (A.D.); (S.C.)
| | | | - Alexej Dick
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, USA; (I.S.S.); (A.D.); (S.C.)
| | - Simon Cocklin
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, USA; (I.S.S.); (A.D.); (S.C.)
| | - Alexander V. Mazin
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, USA; (I.S.S.); (A.D.); (S.C.)
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, TX 78229, USA
- Correspondence:
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12
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Argunhan B, Iwasaki H, Tsubouchi H. Post-translational modification of factors involved in homologous recombination. DNA Repair (Amst) 2021; 104:103114. [PMID: 34111757 DOI: 10.1016/j.dnarep.2021.103114] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 03/29/2021] [Accepted: 03/31/2021] [Indexed: 02/04/2023]
Abstract
DNA is the molecule that stores the chemical instructions necessary for life and its stability is therefore of the utmost importance. Despite this, DNA is damaged by both exogenous and endogenous factors at an alarming frequency. The most severe type of DNA damage is a double-strand break (DSB), in which a scission occurs in both strands of the double helix, effectively dividing a single normal chromosome into two pathological chromosomes. Homologous recombination (HR) is a universal DSB repair mechanism that solves this problem by identifying another region of the genome that shares high sequence similarity with the DSB site and using it as a template for repair. Rad51 possess the enzymatic activity that is essential for this repair but several auxiliary factors are required for Rad51 to fulfil its function. It is becoming increasingly clear that many HR factors are subjected to post-translational modification. Here, we review what is known about how these modifications affect HR. We first focus on cases where there is experimental evidence to support a function for the modification, then discuss speculative cases where a function can be inferred. Finally, we contemplate why such modifications might be necessary.
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Affiliation(s)
- Bilge Argunhan
- Institute of Innovative Research, Tokyo Institute of Technology, Tokyo, Japan.
| | - Hiroshi Iwasaki
- Institute of Innovative Research, Tokyo Institute of Technology, Tokyo, Japan; School of Life Science and Technology, Tokyo Institute of Technology, Tokyo, Japan
| | - Hideo Tsubouchi
- Institute of Innovative Research, Tokyo Institute of Technology, Tokyo, Japan; School of Life Science and Technology, Tokyo Institute of Technology, Tokyo, Japan
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13
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Afshar N, Argunhan B, Palihati M, Taniguchi G, Tsubouchi H, Iwasaki H. A novel motif of Rad51 serves as an interaction hub for recombination auxiliary factors. eLife 2021; 10:64131. [PMID: 33493431 PMCID: PMC7837696 DOI: 10.7554/elife.64131] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Accepted: 12/26/2020] [Indexed: 12/14/2022] Open
Abstract
Homologous recombination (HR) is essential for maintaining genome stability. Although Rad51 is the key protein that drives HR, multiple auxiliary factors interact with Rad51 to potentiate its activity. Here, we present an interdisciplinary characterization of the interactions between Rad51 and these factors. Through structural analysis, we identified an evolutionarily conserved acidic patch of Rad51. The neutralization of this patch completely abolished recombinational DNA repair due to defects in the recruitment of Rad51 to DNA damage sites. This acidic patch was found to be important for the interaction with Rad55-Rad57 and essential for the interaction with Rad52. Furthermore, biochemical reconstitutions demonstrated that neutralization of this acidic patch also impaired the interaction with Rad54, indicating that a single motif is important for the interaction with multiple auxiliary factors. We propose that this patch is a fundamental motif that facilitates interactions with auxiliary factors and is therefore essential for recombinational DNA repair.
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Affiliation(s)
- Negar Afshar
- School of Life Science and Technology, Tokyo Institute of Technology, Tokyo, Japan.,Institute of Innovative Research, Tokyo Institute of Technology, Tokyo, Japan
| | - Bilge Argunhan
- Institute of Innovative Research, Tokyo Institute of Technology, Tokyo, Japan
| | - Maierdan Palihati
- School of Life Science and Technology, Tokyo Institute of Technology, Tokyo, Japan.,Institute of Innovative Research, Tokyo Institute of Technology, Tokyo, Japan
| | - Goki Taniguchi
- School of Life Science and Technology, Tokyo Institute of Technology, Tokyo, Japan.,Institute of Innovative Research, Tokyo Institute of Technology, Tokyo, Japan
| | - Hideo Tsubouchi
- School of Life Science and Technology, Tokyo Institute of Technology, Tokyo, Japan.,Institute of Innovative Research, Tokyo Institute of Technology, Tokyo, Japan
| | - Hiroshi Iwasaki
- School of Life Science and Technology, Tokyo Institute of Technology, Tokyo, Japan.,Institute of Innovative Research, Tokyo Institute of Technology, Tokyo, Japan
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BRET- and fluorescence anisotropy-based assays for real-time monitoring of ligand binding to M 2 muscarinic acetylcholine receptors. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2020; 1868:118930. [PMID: 33347921 DOI: 10.1016/j.bbamcr.2020.118930] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 11/26/2020] [Accepted: 12/11/2020] [Indexed: 12/14/2022]
Abstract
BRET and fluorescence anisotropy (FA) are two fluorescence-based techniques used for the characterization of ligand binding to G protein-coupled receptors (GPCRs) and both allow monitoring of ligand binding in real time. In this study, we present the first direct comparison of BRET-based and FA-based binding assays using the human M2 muscarinic acetylcholine receptor (M2R) and two TAMRA (5-carboxytetramethylrhodamine)-labeled fluorescent ligands as a model system. The determined fluorescent ligand affinities from both assays were in good agreement with results obtained from radioligand competition binding experiments. The assays yielded real-time kinetic binding data revealing differences in the mechanism of binding for the investigated fluorescent probes. Furthermore, the investigation of various unlabeled M2R ligands yielded pharmacological profiles in accordance with earlier reported data. Taken together, this study showed that BRET- and FA-based binding assays represent valuable alternatives to radioactivity-based methods for screening purposes and for a precise characterization of binding kinetics supporting the exploration of binding mechanisms.
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