1
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Jirapongwattana N, Bunting SF, Ronning DR, Ghosal G, Karpf AR. RHNO1: at the crossroads of DNA replication stress, DNA repair, and cancer. Oncogene 2024; 43:2613-2620. [PMID: 39107463 DOI: 10.1038/s41388-024-03117-x] [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: 06/03/2024] [Revised: 07/24/2024] [Accepted: 07/26/2024] [Indexed: 08/28/2024]
Abstract
The DNA replication stress (DRS) response is a crucial homeostatic mechanism for maintaining genome integrity in the face of intrinsic and extrinsic barriers to DNA replication. Importantly, DRS is often significantly increased in tumor cells, making tumors dependent on the cellular DRS response for growth and survival. Rad9-Hus1-Rad1 Interacting Nuclear Orphan 1 (RHNO1), a protein involved in the DRS response, has recently emerged as a potential therapeutic target in cancer. RHNO1 interacts with the 9-1-1 checkpoint clamp and TopBP1 to activate the ATR/Chk1 signaling pathway, the crucial mediator of the DRS response. Moreover, RHNO1 was also recently identified as a key facilitator of theta-mediated end joining (TMEJ), a DNA repair mechanism implicated in cancer progression and chemoresistance. In this literature review, we provide an overview of our current understanding of RHNO1, including its structure, function in the DRS response, and role in DNA repair, and discuss its potential as a cancer therapeutic target. Therapeutic targeting of RHNO1 holds promise for tumors with elevated DRS as well as tumors with DNA repair deficiencies, including homologous recombination DNA repair deficient (HRD) tumors. Further investigation into RHNO1 function in cancer, and development of approaches to target RHNO1, are expected to yield novel strategies for cancer treatment.
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Affiliation(s)
- Niphat Jirapongwattana
- Eppley Institute for Research in Cancer, University of Nebraska Medical Center, Omaha, NE, 68198-6805, USA
- Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, 68198-6805, USA
| | - Samuel F Bunting
- Department of Molecular Biology and Biochemistry, Rutgers, The State University of New Jersey, Piscataway, NJ, 08854-8021, USA
| | - Donald R Ronning
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE, 68198-6805, USA
| | - Gargi Ghosal
- Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, 68198-6805, USA
- Department of Genetics, Cell Biology, and Anatomy, University of Nebraska Medical Center, Omaha, NE, 68198-6805, USA
| | - Adam R Karpf
- Eppley Institute for Research in Cancer, University of Nebraska Medical Center, Omaha, NE, 68198-6805, USA.
- Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, 68198-6805, USA.
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2
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Huang W, Qiu F, Zheng L, Shi M, Shen M, Zhao X, Xiang S. Structural insights into Rad18 targeting by the SLF1 BRCT domains. J Biol Chem 2023; 299:105288. [PMID: 37748650 PMCID: PMC10598736 DOI: 10.1016/j.jbc.2023.105288] [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: 06/24/2023] [Revised: 09/18/2023] [Accepted: 09/20/2023] [Indexed: 09/27/2023] Open
Abstract
Rad18 interacts with the SMC5/6 localization factor 1 (SLF1) to recruit the SMC5/6 complex to DNA damage sites for repair. The mechanism of the specific Rad18 recognition by SLF1 is unclear. Here, we present the crystal structure of the tandem BRCT repeat (tBRCT) in SLF1 (SLF1tBRCT) bound with the interacting Rad18 peptide. Our structure and biochemical studies demonstrate that SLF1tBRCT interacts with two phosphoserines and adjacent residues in Rad18 for high-affinity and specificity Rad18 recognition. We found that SLF1tBRCT utilizes mechanisms common among tBRCTs as well as unique ones for Rad18 binding, the latter include interactions with an α-helical structure in Rad18 that has not been observed in other tBRCT-bound ligand proteins. Our work provides structural insights into Rad18 targeting by SLF1 and expands the understanding of BRCT-mediated complex assembly.
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Affiliation(s)
- Wei Huang
- Department of Biochemistry and Molecular Biology, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Tianjin Medical University, Tianjin, P. R. China
| | - Fangjie Qiu
- Department of Biochemistry and Molecular Biology, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Tianjin Medical University, Tianjin, P. R. China
| | - Lin Zheng
- Department of Biochemistry and Molecular Biology, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Tianjin Medical University, Tianjin, P. R. China
| | - Meng Shi
- Department of Biochemistry and Molecular Biology, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Tianjin Medical University, Tianjin, P. R. China
| | - Miaomiao Shen
- National Clinical Research Center for Cancer, Tianjin Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin Medical University Cancer Institute and Hospital, Tianjin, P. R. China
| | - Xiaolan Zhao
- Department of Molecular Biology, Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | - Song Xiang
- Department of Biochemistry and Molecular Biology, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Tianjin Medical University, Tianjin, P. R. China.
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3
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Day M, Oliver AW, Pearl LH. Phosphorylation-dependent assembly of DNA damage response systems and the central roles of TOPBP1. DNA Repair (Amst) 2021; 108:103232. [PMID: 34678589 PMCID: PMC8651625 DOI: 10.1016/j.dnarep.2021.103232] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 09/23/2021] [Accepted: 09/24/2021] [Indexed: 11/11/2022]
Abstract
The cellular response to DNA damage (DDR) that causes replication collapse and/or DNA double strand breaks, is characterised by a massive change in the post-translational modifications (PTM) of hundreds of proteins involved in the detection and repair of DNA damage, and the communication of the state of damage to the cellular systems that regulate replication and cell division. A substantial proportion of these PTMs involve targeted phosphorylation, which among other effects, promotes the formation of multiprotein complexes through the specific binding of phosphorylated motifs on one protein, by specialised domains on other proteins. Understanding the nature of these phosphorylation mediated interactions allows definition of the pathways and networks that coordinate the DDR, and helps identify new targets for therapeutic intervention that may be of benefit in the treatment of cancer, where DDR plays a key role. In this review we summarise the present understanding of how phosphorylated motifs are recognised by BRCT domains, which occur in many DDR proteins. We particularly focus on TOPBP1 - a multi-BRCT domain scaffold protein with essential roles in replication and the repair and signalling of DNA damage.
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Affiliation(s)
- Matthew Day
- Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK
| | - Antony W Oliver
- Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK
| | - Laurence H Pearl
- Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK; Division of Structural Biology, Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London SW1E 6BT, UK.
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4
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Prabhakar AT, James CD, Das D, Otoa R, Day M, Burgner J, Fontan CT, Wang X, Glass SH, Wieland A, Donaldson MM, Bristol ML, Li R, Oliver AW, Pearl LH, Smith BO, Morgan IM. CK2 Phosphorylation of Human Papillomavirus 16 E2 on Serine 23 Promotes Interaction with TopBP1 and Is Critical for E2 Interaction with Mitotic Chromatin and the Viral Life Cycle. mBio 2021; 12:e0116321. [PMID: 34544280 PMCID: PMC8546539 DOI: 10.1128/mbio.01163-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2021] [Accepted: 08/19/2021] [Indexed: 01/05/2023] Open
Abstract
During the human papillomavirus 16 (HPV16) life cycle, the E2 protein interacts with host factors to regulate viral transcription, replication, and genome segregation/retention. Our understanding of host partner proteins and their roles in E2 functions remains incomplete. Here we demonstrate that CK2 phosphorylation of E2 on serine 23 promotes interaction with TopBP1 in vitro and in vivo and that E2 is phosphorylated on this residue during the HPV16 life cycle. We investigated the consequences of mutating serine 23 on E2 functions. E2-S23A (E2 with serine 23 mutated to alanine) activates and represses transcription identically to E2-WT (wild-type E2), and E2-S23A is as efficient as E2-WT in transient replication assays. However, E2-S23A has compromised interaction with mitotic chromatin compared with E2-WT. In E2-WT cells, both E2 and TopBP1 levels increase during mitosis compared with vector control cells. In E2-S23A cells, neither E2 nor TopBP1 levels increase during mitosis. Introduction of the S23A mutation into the HPV16 genome resulted in delayed immortalization of human foreskin keratinocytes (HFK) and higher episomal viral genome copy number in resulting established HFK. Remarkably, S23A cells had a disrupted viral life cycle in organotypic raft cultures, with a loss of E2 expression and a failure of viral replication. Overall, our results demonstrate that CK2 phosphorylation of E2 on serine 23 promotes interaction with TopBP1 and that this interaction is critical for the viral life cycle. IMPORTANCE Human papillomaviruses are causative agents in around 5% of all cancers, with no specific antiviral therapeutics available for treating infections or resultant cancers. In this report, we demonstrate that phosphorylation of HPV16 E2 by CK2 promotes formation of a complex with the cellular protein TopBP1 in vitro and in vivo. This complex results in stabilization of E2 during mitosis. We demonstrate that CK2 phosphorylates E2 on serine 23 in vivo and that CK2 inhibitors disrupt the E2-TopBP1 complex. Mutation of E2 serine 23 to alanine disrupts the HPV16 life cycle, hindering immortalization and disrupting the viral life cycle, demonstrating a critical function for this residue.
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Affiliation(s)
- Apurva T. Prabhakar
- Virginia Commonwealth University (VCU), Philips Institute for Oral Health Research, School of Dentistry, Richmond, Virginia, USA
| | - Claire D. James
- Virginia Commonwealth University (VCU), Philips Institute for Oral Health Research, School of Dentistry, Richmond, Virginia, USA
| | - Dipon Das
- Virginia Commonwealth University (VCU), Philips Institute for Oral Health Research, School of Dentistry, Richmond, Virginia, USA
| | - Raymonde Otoa
- Virginia Commonwealth University (VCU), Philips Institute for Oral Health Research, School of Dentistry, Richmond, Virginia, USA
| | - Matthew Day
- Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - John Burgner
- Virginia Commonwealth University (VCU), Philips Institute for Oral Health Research, School of Dentistry, Richmond, Virginia, USA
| | - Christian T. Fontan
- Virginia Commonwealth University (VCU), Philips Institute for Oral Health Research, School of Dentistry, Richmond, Virginia, USA
| | - Xu Wang
- Virginia Commonwealth University (VCU), Philips Institute for Oral Health Research, School of Dentistry, Richmond, Virginia, USA
| | - Sarah H. Glass
- VCU School of Dentistry, Department of Oral Diagnostic Sciences, Richmond, Virginia, USA
| | - Andreas Wieland
- Emory Vaccine Center, Emory University School of Medicine, Atlanta, Georgia, USA
- Department of Microbiology & Immunology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Mary M. Donaldson
- School of Veterinary Medicine, University of Glasgow, Bearsden, United Kingdom
| | - Molly L. Bristol
- Virginia Commonwealth University (VCU), Philips Institute for Oral Health Research, School of Dentistry, Richmond, Virginia, USA
| | - Renfeng Li
- Virginia Commonwealth University (VCU), Philips Institute for Oral Health Research, School of Dentistry, Richmond, Virginia, USA
- VCU Massey Cancer Center, Richmond, Virginia, USA
| | - Anthony W. Oliver
- Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - Laurence H. Pearl
- Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - Brian O. Smith
- Institute of Molecular, Cell & Systems Biology, University of Glasgow, Glasgow, United Kingdom
| | - Iain M. Morgan
- Virginia Commonwealth University (VCU), Philips Institute for Oral Health Research, School of Dentistry, Richmond, Virginia, USA
- VCU Massey Cancer Center, Richmond, Virginia, USA
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5
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Ovejero S, Bueno A, Sacristán MP. Working on Genomic Stability: From the S-Phase to Mitosis. Genes (Basel) 2020; 11:E225. [PMID: 32093406 PMCID: PMC7074175 DOI: 10.3390/genes11020225] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 02/17/2020] [Accepted: 02/18/2020] [Indexed: 12/15/2022] Open
Abstract
Fidelity in chromosome duplication and segregation is indispensable for maintaining genomic stability and the perpetuation of life. Challenges to genome integrity jeopardize cell survival and are at the root of different types of pathologies, such as cancer. The following three main sources of genomic instability exist: DNA damage, replicative stress, and chromosome segregation defects. In response to these challenges, eukaryotic cells have evolved control mechanisms, also known as checkpoint systems, which sense under-replicated or damaged DNA and activate specialized DNA repair machineries. Cells make use of these checkpoints throughout interphase to shield genome integrity before mitosis. Later on, when the cells enter into mitosis, the spindle assembly checkpoint (SAC) is activated and remains active until the chromosomes are properly attached to the spindle apparatus to ensure an equal segregation among daughter cells. All of these processes are tightly interconnected and under strict regulation in the context of the cell division cycle. The chromosomal instability underlying cancer pathogenesis has recently emerged as a major source for understanding the mitotic processes that helps to safeguard genome integrity. Here, we review the special interconnection between the S-phase and mitosis in the presence of under-replicated DNA regions. Furthermore, we discuss what is known about the DNA damage response activated in mitosis that preserves chromosomal integrity.
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Affiliation(s)
- Sara Ovejero
- Instituto de Biología Molecular y Celular del Cáncer (IBMCC), Universidad de Salamanca-CSIC, Campus Miguel de Unamuno, 37007 Salamanca, Spain
- Institute of Human Genetics, CNRS, University of Montpellier, 34000 Montpellier, France
- Department of Biological Hematology, CHU Montpellier, 34295 Montpellier, France
| | - Avelino Bueno
- Instituto de Biología Molecular y Celular del Cáncer (IBMCC), Universidad de Salamanca-CSIC, Campus Miguel de Unamuno, 37007 Salamanca, Spain
- Departamento de Microbiología y Genética, Universidad de Salamanca, Campus Miguel de Unamuno, 37007 Salamanca, Spain
| | - María P. Sacristán
- Instituto de Biología Molecular y Celular del Cáncer (IBMCC), Universidad de Salamanca-CSIC, Campus Miguel de Unamuno, 37007 Salamanca, Spain
- Departamento de Microbiología y Genética, Universidad de Salamanca, Campus Miguel de Unamuno, 37007 Salamanca, Spain
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6
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Structure and regulation of human epithelial cell transforming 2 protein. Proc Natl Acad Sci U S A 2019; 117:1027-1035. [PMID: 31888991 DOI: 10.1073/pnas.1913054117] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Epithelial cell transforming 2 (Ect2) protein activates Rho GTPases and controls cytokinesis and many other cellular processes. Dysregulation of Ect2 is associated with various cancers. Here, we report the crystal structure of human Ect2 and complementary mechanistic analyses. The data show the C-terminal PH domain of Ect2 folds back and blocks the canonical RhoA-binding site at the catalytic center of the DH domain, providing a mechanism of Ect2 autoinhibition. Ect2 is activated by binding of GTP-bound RhoA to the PH domain, which suggests an allosteric mechanism of Ect2 activation and a positive-feedback loop reinforcing RhoA signaling. This bimodal RhoA binding of Ect2 is unusual and was confirmed with Förster resonance energy transfer (FRET) and hydrogen-deuterium exchange mass spectrometry (HDX-MS) analyses. Several recurrent cancer-associated mutations map to the catalytic and regulatory interfaces, and dysregulate Ect2 in vitro and in vivo. Together, our findings provide mechanistic insights into Ect2 regulation in normal cells and under disease conditions.
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7
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Wu T, Zhang Z, Wang X. Preparation of endogenous TopBP1/Dpb11 and effect on central checkpoint kinase Mec1- Ddc2 (human ATR-ATRIP homolog). Biochem Biophys Res Commun 2019; 517:291-296. [PMID: 31349966 DOI: 10.1016/j.bbrc.2019.07.055] [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: 07/06/2019] [Accepted: 07/17/2019] [Indexed: 11/18/2022]
Abstract
The Saccharomyces cerevisiae Mec1 kinase, the mammalian ATR ortholog, is essential for sensing a variety of DNA lesions and initiating DNA damage response. The Dpb11, a homolog of human TopBP1, functions in activating the Mec1 upon DNA replication stress and DNA damages. Here, we report an affinity purification and ion exchange chromatography method to efficiently purify endogenous Dpb11 under normal expression level directly from yeast whole cell extraction. The final concentration of 5 μM of high purity and homogeneity biochemical preparation enables functional and structural characterization of the physical interaction between Dpb11 and Mec1-Ddc2 complex. The Dpb11 obtained by endogenous purification strongly stimulates the Mec1 kinase activity and promotes the changes in conformational distribution. This observation suggests the Dpb11 activates Mec1 kinase probably through modulation in the kinase conformations.
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Affiliation(s)
- Tengwei Wu
- School of Life Sciences, University of Science and Technology of China, Hefei, 230027, Anhui, China and Hefei National Laboratory for Physical Sciences at Microscale, Hefei, 230026, Anhui, China
| | - Zhihui Zhang
- School of Life Sciences, University of Science and Technology of China, Hefei, 230027, Anhui, China and Hefei National Laboratory for Physical Sciences at Microscale, Hefei, 230026, Anhui, China
| | - Xuejuan Wang
- School of Life Sciences, University of Science and Technology of China, Hefei, 230027, Anhui, China and Hefei National Laboratory for Physical Sciences at Microscale, Hefei, 230026, Anhui, China.
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8
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Bigot N, Day M, Baldock RA, Watts FZ, Oliver AW, Pearl LH. Phosphorylation-mediated interactions with TOPBP1 couple 53BP1 and 9-1-1 to control the G1 DNA damage checkpoint. eLife 2019; 8:e44353. [PMID: 31135337 PMCID: PMC6561707 DOI: 10.7554/elife.44353] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 05/25/2019] [Indexed: 12/30/2022] Open
Abstract
Coordination of the cellular response to DNA damage is organised by multi-domain 'scaffold' proteins, including 53BP1 and TOPBP1, which recognise post-translational modifications such as phosphorylation, methylation and ubiquitylation on other proteins, and are themselves carriers of such regulatory signals. Here we show that the DNA damage checkpoint regulating S-phase entry is controlled by a phosphorylation-dependent interaction of 53BP1 and TOPBP1. BRCT domains of TOPBP1 selectively bind conserved phosphorylation sites in the N-terminus of 53BP1. Mutation of these sites does not affect formation of 53BP1 or ATM foci following DNA damage, but abolishes recruitment of TOPBP1, ATR and CHK1 to 53BP1 damage foci, abrogating cell cycle arrest and permitting progression into S-phase. TOPBP1 interaction with 53BP1 is structurally complimentary to its interaction with RAD9-RAD1-HUS1, allowing these damage recognition factors to bind simultaneously to the same TOPBP1 molecule and cooperate in ATR activation in the G1 DNA damage checkpoint.
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Affiliation(s)
- Nicolas Bigot
- Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life SciencesUniversity of SussexBrightonUnited Kingdom
| | - Matthew Day
- Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life SciencesUniversity of SussexBrightonUnited Kingdom
| | - Robert A Baldock
- Genome Damage and Stability Centre, School of Life SciencesUniversity of SussexBrightonUnited Kingdom
| | - Felicity Z Watts
- Genome Damage and Stability Centre, School of Life SciencesUniversity of SussexBrightonUnited Kingdom
| | - Antony W Oliver
- Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life SciencesUniversity of SussexBrightonUnited Kingdom
| | - Laurence H Pearl
- Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life SciencesUniversity of SussexBrightonUnited Kingdom
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9
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Polo LM, Xu Y, Hornyak P, Garces F, Zeng Z, Hailstone R, Matthews SJ, Caldecott KW, Oliver AW, Pearl LH. Efficient Single-Strand Break Repair Requires Binding to Both Poly(ADP-Ribose) and DNA by the Central BRCT Domain of XRCC1. Cell Rep 2019; 26:573-581.e5. [PMID: 30650352 PMCID: PMC6334254 DOI: 10.1016/j.celrep.2018.12.082] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 11/26/2018] [Accepted: 12/18/2018] [Indexed: 12/11/2022] Open
Abstract
XRCC1 accelerates repair of DNA single-strand breaks by acting as a scaffold protein for the recruitment of Polβ, LigIIIα, and end-processing factors, such as PNKP and APTX. XRCC1 itself is recruited to DNA damage through interaction of its central BRCT domain with poly(ADP-ribose) chains generated by PARP1 or PARP2. XRCC1 is believed to interact directly with DNA at sites of damage, but the molecular basis for this interaction within XRCC1 remains unclear. We now show that the central BRCT domain simultaneously mediates interaction of XRCC1 with poly(ADP-ribose) and DNA, through separate and non-overlapping binding sites on opposite faces of the domain. Mutation of residues within the DNA binding site, which includes the site of a common disease-associated human polymorphism, affects DNA binding of this XRCC1 domain in vitro and impairs XRCC1 recruitment and retention at DNA damage and repair of single-strand breaks in vivo.
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Affiliation(s)
- Luis M Polo
- Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK
| | - Yingqi Xu
- Cross-Faculty NMR Centre, Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, UK
| | - Peter Hornyak
- Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK; Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK
| | - Fernando Garces
- Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK
| | - Zhihong Zeng
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK
| | - Richard Hailstone
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK
| | - Steve J Matthews
- Cross-Faculty NMR Centre, Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, UK
| | - Keith W Caldecott
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK.
| | - Antony W Oliver
- Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK.
| | - Laurence H Pearl
- Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK; Division of Structural Biology, Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London SW1E 6BT, UK.
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10
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Day M, Rappas M, Ptasinska K, Boos D, Oliver AW, Pearl LH. BRCT domains of the DNA damage checkpoint proteins TOPBP1/Rad4 display distinct specificities for phosphopeptide ligands. eLife 2018; 7:e39979. [PMID: 30295604 PMCID: PMC6175577 DOI: 10.7554/elife.39979] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 09/24/2018] [Indexed: 12/28/2022] Open
Abstract
TOPBP1 and its fission yeast homologueRad4, are critical players in a range of DNA replication, repair and damage signalling processes. They are composed of multiple BRCT domains, some of which bind phosphorylated motifs in other proteins. They thus act as multi-point adaptors bringing proteins together into functional combinations, dependent on post-translational modifications downstream of cell cycle and DNA damage signals. We have now structurally and/or biochemically characterised a sufficient number of high-affinity complexes for the conserved N-terminal region of TOPBP1 and Rad4 with diverse phospho-ligands, including human RAD9 and Treslin, and Schizosaccharomyces pombe Crb2 and Sld3, to define the determinants of BRCT domain specificity. We use this to identify and characterise previously unknown phosphorylation-dependent TOPBP1/Rad4-binding motifs in human RHNO1 and the fission yeast homologue of MDC1, Mdb1. These results provide important insights into how multiple BRCT domains within TOPBP1/Rad4 achieve selective and combinatorial binding of their multiple partner proteins.
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Affiliation(s)
- Matthew Day
- Cancer Research UK DNA Repair Enzymes GroupGenome Damage and Stability Centre, School of Life Sciences, University of SussexFalmerUnited Kingdom
| | - Mathieu Rappas
- Cancer Research UK DNA Repair Enzymes GroupGenome Damage and Stability Centre, School of Life Sciences, University of SussexFalmerUnited Kingdom
| | - Katie Ptasinska
- Genome Damage and Stability CentreSchool of Life Sciences, University of SussexFalmerUnited Kingdom
| | - Dominik Boos
- Fakultät für BiologieUniversität Duisburg-EssenGermanyUnited Kingdom
| | - Antony W Oliver
- Cancer Research UK DNA Repair Enzymes GroupGenome Damage and Stability Centre, School of Life Sciences, University of SussexFalmerUnited Kingdom
| | - Laurence H Pearl
- Cancer Research UK DNA Repair Enzymes GroupGenome Damage and Stability Centre, School of Life Sciences, University of SussexFalmerUnited Kingdom
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11
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Sun L, Huang Y, Edwards RA, Yang S, Blackford AN, Niedzwiedz W, Glover JNM. Structural Insight into BLM Recognition by TopBP1. Structure 2017; 25:1582-1588.e3. [PMID: 28919440 PMCID: PMC6044410 DOI: 10.1016/j.str.2017.08.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2017] [Revised: 07/28/2017] [Accepted: 08/15/2017] [Indexed: 01/07/2023]
Abstract
Topoisomerase IIβ binding protein 1 (TopBP1) is a critical protein-protein interaction hub in DNA replication checkpoint control. It was proposed that TopBP1 BRCT5 interacts with Bloom syndrome helicase (BLM) to regulate genome stability through either phospho-Ser304 or phospho-Ser338 of BLM. Here we show that TopBP1 BRCT5 specifically interacts with the BLM region surrounding pSer304, not pSer338. Our crystal structure of TopBP1 BRCT4/5 bound to BLM reveals recognition of pSer304 by a conserved pSer-binding pocket, and interactions between an FVPP motif N-terminal to pSer304 and a hydrophobic groove on BRCT5. This interaction utilizes the same surface of BRCT5 that recognizes the DNA damage mediator, MDC1; however the binding orientations of MDC1 and BLM are reversed. While the MDC1 interactions are largely electrostatic, the interaction with BLM has higher affinity and relies on a mix of electrostatics and hydrophobicity. We suggest that similar evolutionarily conserved interactions may govern interactions between TopBP1 and 53BP1.
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Affiliation(s)
- Luxin Sun
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Yuhao Huang
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Ross A Edwards
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Sukmin Yang
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Andrew N Blackford
- Department of Oncology, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK; Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, University of Oxford, Oxford OX3 7DQ, UK
| | - Wojciech Niedzwiedz
- Department of Oncology, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK
| | - J N Mark Glover
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada.
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12
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Abstract
Tandem BRCT domains are phophoprotein binding modules. In this issue of Structure, Sun et al. (2017) show that a single BRCT domain in TopBP1 binds tightly and specifically to phosphorylated Bloom syndrome helicase (BLM). This work reveals a novel BRCT binding mode and suggests a similar mechanism for TopBP1 interaction with 53BP1.
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Affiliation(s)
- Georges Mer
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
| | - Maria Victoria Botuyan
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA.
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13
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Chen YH, Wang GY, Hao HC, Chao CJ, Wang Y, Jin QW. Facile manipulation of protein localization in fission yeast through binding of GFP-binding protein to GFP. J Cell Sci 2017; 130:1003-1015. [PMID: 28082423 DOI: 10.1242/jcs.198457] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 01/05/2017] [Indexed: 12/20/2022] Open
Abstract
GFP-binding protein (or GBP) has been recently developed in various systems and organisms as an efficient tool to purify GFP-fusion proteins. Due to the high affinity between GBP and GFP or GFP variants, this GBP-based approach is also ideally suited to alter the localization of functional proteins in live cells. In order to facilitate the wide use of the GBP-targeting approach in the fission yeast Schizosaccharomyces pombe, we developed a set of pFA6a-, pJK148- and pUC119-based vectors containing GBP- or GBP-mCherry-coding sequences and variants of inducible nmt1 or constitutive adh1 promoters that result in different levels of expression. The GBP or GBP-mCherry fragments can serve as cassettes for N- or C-terminal genomic tagging of genes of interest. We illustrated the application of these vectors in the construction of yeast strains with Dma1 or Cdc7 tagged with GBP-mCherry and efficient targeting of Dma1- or Cdc7-GBP-mCherry to the spindle pole body by Sid4-GFP. This series of vectors should help to facilitate the application of the GBP-targeting approach in manipulating protein localization and the analysis of gene function in fission yeast, at the level of single genes, as well as at a systematic scale.
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Affiliation(s)
- Ying-Hui Chen
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Gao-Yuan Wang
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Hao-Chao Hao
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Chun-Jiang Chao
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Yamei Wang
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Quan-Wen Jin
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
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14
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Wan B, Hang LE, Zhao X. Multi-BRCT scaffolds use distinct strategies to support genome maintenance. Cell Cycle 2016; 15:2561-2570. [PMID: 27580271 DOI: 10.1080/15384101.2016.1218102] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Genome maintenance requires coordinated actions of diverse DNA metabolism processes. Scaffolding proteins, such as those containing multiple BRCT domains, can influence these processes by collaborating with numerous partners. The best-studied examples of multi-BRCT scaffolds are the budding yeast Dpb11 and its homologues in other organisms, which regulate DNA replication, repair, and damage checkpoints. Recent studies have shed light on another group of multi-BRCT scaffolds, including Rtt107 in budding yeast and related proteins in other organisms. These proteins also influence several DNA metabolism pathways, though they use strategies unlike those employed by the Dpb11 family of proteins. Yet, at the same time, these 2 classes of multi-BRCT proteins can collaborate under specific situations. This review summarizes recent advances in our understanding of how these multi-BRCT proteins function in distinct manners and how they collaborate, with a focus on Dpb11 and Rtt107.
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Affiliation(s)
- Bingbing Wan
- a Molecular Biology Program, Memorial Sloan Kettering Cancer Center , New York , NY , USA
| | - Lisa E Hang
- a Molecular Biology Program, Memorial Sloan Kettering Cancer Center , New York , NY , USA
| | - Xiaolan Zhao
- a Molecular Biology Program, Memorial Sloan Kettering Cancer Center , New York , NY , USA
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15
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Liu Y, Smolka MB. TOPBP1 takes RADical command in recombinational DNA repair. J Cell Biol 2016; 212:263-6. [PMID: 26811424 PMCID: PMC4748579 DOI: 10.1083/jcb.201601028] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 01/08/2016] [Indexed: 12/15/2022] Open
Abstract
TOPBP1 is a key player in DNA replication and DNA damage signaling. In this issue, Moudry et al. (2016. J. Cell Biol.http://dx.doi.org/10.1083/jcb.201507042) uncover a crucial role for TOPBP1 in DNA repair by revealing its requirement for RAD51 loading during repair of double strand breaks by homologous recombination.
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Affiliation(s)
- Yi Liu
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853
| | - Marcus B Smolka
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853
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16
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Huet S, Gorre H, Perrocheau A, Picot J, Cinier M. Use of the Nanofitin Alternative Scaffold as a GFP-Ready Fusion Tag. PLoS One 2015; 10:e0142304. [PMID: 26539718 PMCID: PMC4634965 DOI: 10.1371/journal.pone.0142304] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 10/19/2015] [Indexed: 11/26/2022] Open
Abstract
With the continuous diversification of recombinant DNA technologies, the possibilities for new tailor-made protein engineering have extended on an on-going basis. Among these strategies, the use of the green fluorescent protein (GFP) as a fusion domain has been widely adopted for cellular imaging and protein localization. Following the lead of the direct head-to-tail fusion of GFP, we proposed to provide additional features to recombinant proteins by genetic fusion of artificially derived binders. Thus, we reported a GFP-ready fusion tag consisting of a small and robust fusion-friendly anti-GFP Nanofitin binding domain as a proof-of-concept. While limiting steric effects on the carrier, the GFP-ready tag allows the capture of GFP or its blue (BFP), cyan (CFP) and yellow (YFP) alternatives. Here, we described the generation of the GFP-ready tag from the selection of a Nanofitin variant binding to the GFP and its spectral variants with a nanomolar affinity, while displaying a remarkable folding stability, as demonstrated by its full resistance upon thermal sterilization process or the full chemical synthesis of Nanofitins. To illustrate the potential of the Nanofitin-based tag as a fusion partner, we compared the expression level in Escherichia coli and activity profile of recombinant human tumor necrosis factor alpha (TNFα) constructs, fused to a SUMO or GFP-ready tag. Very similar expression levels were found with the two fusion technologies. Both domains of the GFP-ready tagged TNFα were proved fully active in ELISA and interferometry binding assays, allowing the simultaneous capture by an anti-TNFα antibody and binding to the GFP, and its spectral mutants. The GFP-ready tag was also shown inert in a L929 cell based assay, demonstrating the potent TNFα mediated apoptosis induction by the GFP-ready tagged TNFα. Eventually, we proposed the GFP-ready tag as a versatile capture and labeling system in addition to expected applications of anti-GFP Nanofitins (as illustrated with previously described state-of-the-art anti-GFP binders applied to living cells and in vitro applications). Through a single fusion domain, the GFP-ready tagged proteins benefit from subsequent customization within a wide range of fluorescence spectra upon indirect binding of a chosen GFP variant.
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17
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Luo S, Xin X, Du LL, Ye K, Wei Y. Dimerization Mediated by a Divergent Forkhead-associated Domain Is Essential for the DNA Damage and Spindle Functions of Fission Yeast Mdb1. J Biol Chem 2015; 290:21054-21066. [PMID: 26160178 DOI: 10.1074/jbc.m115.642538] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Indexed: 01/13/2023] Open
Abstract
MDC1 is a key factor of DNA damage response in mammalian cells. It possesses two phospho-binding domains. In its C terminus, a tandem BRCA1 C-terminal domain binds phosphorylated histone H2AX, and in its N terminus, a forkhead-associated (FHA) domain mediates a phosphorylation-enhanced homodimerization. The FHA domain of the Drosophila homolog of MDC1, MU2, also forms a homodimer but utilizes a different dimer interface. The functional importance of the dimerization of MDC1 family proteins is uncertain. In the fission yeast Schizosaccharomyces pombe, a protein sharing homology with MDC1 in the tandem BRCA1 C-terminal domain, Mdb1, regulates DNA damage response and mitotic spindle functions. Here, we report the crystal structure of the N-terminal 91 amino acids of Mdb1. Despite a lack of obvious sequence conservation to the FHA domain of MDC1, this region of Mdb1 adopts an FHA-like fold and is therefore termed Mdb1-FHA. Unlike canonical FHA domains, Mdb1-FHA lacks all the conserved phospho-binding residues. It forms a stable homodimer through an interface distinct from those of MDC1 and MU2. Mdb1-FHA is important for the localization of Mdb1 to DNA damage sites and the spindle midzone, contributes to the roles of Mdb1 in cellular responses to genotoxins and an antimicrotubule drug, and promotes in vitro binding of Mdb1 to a phospho-H2A peptide. The defects caused by the loss of Mdb1-FHA can be rescued by fusion with either of two heterologous dimerization domains, suggesting that the main function of Mdb1-FHA is mediating dimerization. Our data support that FHA-mediated dimerization is conserved for MDC1 family proteins.
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Affiliation(s)
- Shukun Luo
- National Institute of Biological Sciences, Beijing 102206, China
| | - Xiaoran Xin
- National Institute of Biological Sciences, Beijing 102206, China
| | - Li-Lin Du
- National Institute of Biological Sciences, Beijing 102206, China.
| | - Keqiong Ye
- National Institute of Biological Sciences, Beijing 102206, China; Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
| | - Yi Wei
- National Institute of Biological Sciences, Beijing 102206, China
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18
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Cussiol JR, Jablonowski CM, Yimit A, Brown GW, Smolka MB. Dampening DNA damage checkpoint signalling via coordinated BRCT domain interactions. EMBO J 2015; 34:1704-17. [PMID: 25896509 DOI: 10.15252/embj.201490834] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 03/27/2015] [Indexed: 11/09/2022] Open
Abstract
In response to DNA damage, checkpoint signalling protects genome integrity at the cost of repressing cell cycle progression and DNA replication. Mechanisms for checkpoint down-regulation are therefore necessary for proper cellular proliferation. We recently uncovered a phosphatase-independent mechanism for dampening checkpoint signalling, where the checkpoint adaptor Rad9 is counteracted by the repair scaffolds Slx4-Rtt107. Here, we establish the molecular requirements for this new mode of checkpoint regulation. We engineered a minimal multi-BRCT-domain (MBD) module that recapitulates the action of Slx4-Rtt107 in checkpoint down-regulation. MBD mimics the damage-induced Dpb11-Slx4-Rtt107 complex by synergistically interacting with lesion-specific phospho-sites in Ddc1 and H2A. We propose that efficient recruitment of Dpb11-Slx4-Rtt107 or MBD via a cooperative 'two-site-docking' mechanism displaces Rad9. MBD also interacts with the Mus81 nuclease following checkpoint dampening, suggesting a spatio-temporal coordination of checkpoint signalling and DNA repair via a combinatorial mode of BRCT-domains interactions.
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Affiliation(s)
- José R Cussiol
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, USA
| | - Carolyn M Jablonowski
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, USA
| | - Askar Yimit
- Donnelly Centre and Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Grant W Brown
- Donnelly Centre and Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Marcus B Smolka
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, USA
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19
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Wardlaw CP, Carr AM, Oliver AW. TopBP1: A BRCT-scaffold protein functioning in multiple cellular pathways. DNA Repair (Amst) 2014; 22:165-74. [PMID: 25087188 DOI: 10.1016/j.dnarep.2014.06.004] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 06/11/2014] [Indexed: 11/25/2022]
Abstract
Human TopBP1 contains nine BRCT domains and functions in DNA replication initiation, checkpoint signalling, DNA repair and influences transcriptional control. TopBP1 and its homologues have been the subject of numerous scientific publications since the last comprehensive review in 2005, emerging as a key scaffold protein that links crucial components within these distinct cellular processes. This review focuses on recently published work, with particular emphasis on structural insights into TopBP1 function and the binding partners identified for DNA replication initiation, DNA-dependent checkpoints, DNA repair and transcription. We further summarise what is known about TopBP1 and links to human disease.
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Affiliation(s)
- Christopher P Wardlaw
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer BN1 9RQ, UK.
| | - Antony M Carr
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer BN1 9RQ, UK
| | - Antony W Oliver
- Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer BN1 9RQ, UK
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20
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Pal M, Morgan M, Phelps SEL, Roe SM, Parry-Morris S, Downs JA, Polier S, Pearl LH, Prodromou C. Structural basis for phosphorylation-dependent recruitment of Tel2 to Hsp90 by Pih1. Structure 2014; 22:805-18. [PMID: 24794838 PMCID: PMC4058522 DOI: 10.1016/j.str.2014.04.001] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2014] [Revised: 03/24/2014] [Accepted: 04/04/2014] [Indexed: 11/22/2022]
Abstract
Client protein recruitment to the Hsp90 system depends on cochaperones that bind the client and Hsp90 simultaneously and facilitate their interaction. Hsp90 involvement in the assembly of snoRNPs, RNA polymerases, PI3-kinase-like kinases, and chromatin remodeling complexes depends on the TTT (Tel2-Tti1-Tti2), and R2TP complexes-consisting of the AAA-ATPases Rvb1 and Rvb2, Tah1 (Spagh/RPAP3 in metazoa), and Pih1 (Pih1D1 in humans)-that together provide the connection to Hsp90. The biochemistry underlying R2TP function is still poorly understood. Pih1 in particular, at the heart of the complex, has not been described at a structural level, nor have the multiple protein-protein interactions it mediates been characterized. Here we present a structural and biochemical analysis of Hsp90-Tah1-Pih1, Hsp90-Spagh, and Pih1D1-Tel2 complexes that reveal a domain in Pih1D1 specific for binding CK2 phosphorylation sites, and together define the structural basis by which the R2TP complex connects the Hsp90 chaperone system to the TTT complex.
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Affiliation(s)
- Mohinder Pal
- MRC Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK
| | - Marc Morgan
- MRC Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK
| | - Sarah E L Phelps
- MRC Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK
| | - S Mark Roe
- MRC Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK
| | - Sarah Parry-Morris
- MRC Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK
| | - Jessica A Downs
- MRC Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK
| | - Sigrun Polier
- MRC Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK
| | - Laurence H Pearl
- MRC Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK.
| | - Chrisostomos Prodromou
- MRC Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK.
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21
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Mahyous Saeyd SA, Ewert-Krzemieniewska K, Liu B, Caspari T. Hyperactive Cdc2 kinase interferes with the response to broken replication forks by trapping S.pombe Crb2 in its mitotic T215 phosphorylated state. Nucleic Acids Res 2014; 42:7734-47. [PMID: 24861625 PMCID: PMC4081076 DOI: 10.1093/nar/gku452] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Although it is well established that Cdc2 kinase phosphorylates the DNA damage checkpoint protein Crb2(53BP1) in mitosis, the full impact of this modification is still unclear. The Tudor-BRCT domain protein Crb2 binds to modified histones at DNA lesions to mediate the activation of Chk1 by Rad3ATR kinase. We demonstrate here that fission yeast cells harbouring a hyperactive Cdc2CDK1 mutation (cdc2.1w) are specifically sensitive to the topoisomerase 1 inhibitor camptothecin (CPT) which breaks DNA replication forks. Unlike wild-type cells, which delay only briefly in CPT medium by activating Chk1 kinase, cdc2.1w cells bypass Chk1 to enter an extended cell-cycle arrest which depends on Cds1 kinase. Intriguingly, the ability to bypass Chk1 requires the mitotic Cdc2 phosphorylation site Crb2-T215. This implies that the presence of the mitotic phosphorylation at Crb2-T215 channels Rad3 activity towards Cds1 instead of Chk1 when forks break in S phase. We also provide evidence that hyperactive Cdc2.1w locks cells in a G1-like DNA repair mode which favours non-homologous end joining over interchromosomal recombination. Taken together, our data support a model such that elevated Cdc2 activity delays the transition of Crb2 from its G1 to its G2 mode by blocking Srs2 DNA helicase and Casein Kinase 1 (Hhp1).
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Affiliation(s)
- Salah Adam Mahyous Saeyd
- Genome Biology Group, College of Natural Sciences, School of Biological Sciences, Bangor University, Brambell Building, Deiniol Road, Bangor LL57 2UW, Wales, United Kingdom
| | - Katarzyna Ewert-Krzemieniewska
- Genome Biology Group, College of Natural Sciences, School of Biological Sciences, Bangor University, Brambell Building, Deiniol Road, Bangor LL57 2UW, Wales, United Kingdom
| | - Boyin Liu
- Genome Biology Group, College of Natural Sciences, School of Biological Sciences, Bangor University, Brambell Building, Deiniol Road, Bangor LL57 2UW, Wales, United Kingdom
| | - Thomas Caspari
- Genome Biology Group, College of Natural Sciences, School of Biological Sciences, Bangor University, Brambell Building, Deiniol Road, Bangor LL57 2UW, Wales, United Kingdom
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22
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Wei Y, Wang HT, Zhai Y, Russell P, Du LL. Mdb1, a fission yeast homolog of human MDC1, modulates DNA damage response and mitotic spindle function. PLoS One 2014; 9:e97028. [PMID: 24806815 PMCID: PMC4013092 DOI: 10.1371/journal.pone.0097028] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Accepted: 04/14/2014] [Indexed: 11/18/2022] Open
Abstract
During eukaryotic DNA damage response (DDR), one of the earliest events is the phosphorylation of the C-terminal SQ motif of histone H2AX (H2A in yeasts). In human cells, phosphorylated H2AX (γH2AX) is recognized by MDC1, which serves as a binding platform for the accumulation of a myriad of DDR factors on chromatin regions surrounding DNA lesions. Despite its important role in DDR, no homolog of MDC1 outside of metazoans has been described. Here, we report the characterization of Mdb1, a protein from the fission yeast Schizosaccharomyces pombe, which shares significant sequence homology with human MDC1 in their C-terminal tandem BRCT (tBRCT) domains. We show that in vitro, recombinant Mdb1 protein binds a phosphorylated H2A (γH2A) peptide, and the phospho-specific binding requires two conserved phospho-binding residues in the tBRCT domain of Mdb1. In vivo, Mdb1 forms nuclear foci at DNA double strand breaks (DSBs) induced by the HO endonuclease and ionizing radiation (IR). IR-induced Mdb1 focus formation depends on γH2A and the phospho-binding residues of Mdb1. Deleting the mdb1 gene does not overtly affect DNA damage sensitivity in a wild type background, but alters the DNA damage sensitivity of cells lacking another γH2A binder Crb2. Overexpression of Mdb1 causes severe DNA damage sensitivity in a manner that requires the interaction between Mdb1 and γH2A. During mitosis, Mdb1 localizes to spindles and concentrates at spindle midzones at late mitosis. The spindle midzone localization of Mdb1 requires its phospho-binding residues, but is independent of γH2A. Loss of Mdb1 or mutating its phospho-binding residues makes cells more resistant to the microtubule depolymerizing drug thiabendazole. We propose that Mdb1 performs dual roles in DDR and mitotic spindle regulation.
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Affiliation(s)
- Yi Wei
- College of Life Sciences, Beijing Normal University, Beijing, China
- National Institute of Biological Sciences, Beijing, China
| | - Hai-Tao Wang
- National Institute of Biological Sciences, Beijing, China
| | - Yonggong Zhai
- College of Life Sciences, Beijing Normal University, Beijing, China
| | - Paul Russell
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, California, United States of America
- * E-mail: (PR); (LLD)
| | - Li-Lin Du
- National Institute of Biological Sciences, Beijing, China
- * E-mail: (PR); (LLD)
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23
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Belfield C, Queenan C, Rao H, Kitamura K, Walworth NC. The oxidative stress responsive transcription factor Pap1 confers DNA damage resistance on checkpoint-deficient fission yeast cells. PLoS One 2014; 9:e89936. [PMID: 24587136 PMCID: PMC3934961 DOI: 10.1371/journal.pone.0089936] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Accepted: 01/28/2014] [Indexed: 11/19/2022] Open
Abstract
Eukaryotic cells invoke mechanisms to promote survival when confronted with cellular stress or damage to the genome. The protein kinase Chk1 is an integral and conserved component of the DNA damage response pathway. Mutation or inhibition of Chk1 results in mitotic death when cells are exposed to DNA damage. Oxidative stress activates a pathway that results in nuclear accumulation of the bZIP transcription factor Pap1. We report the novel finding that fission yeast Pap1 confers resistance to drug- and non-drug-induced DNA damage even when the DNA damage checkpoint is compromised. Multi-copy expression of Pap1 restores growth to chk1-deficient cells exposed to camptothecin or hydroxyurea. Unexpectedly, increased Pap1 expression also promotes survival of chk1-deficient cells with mutations in genes encoding DNA ligase (cdc17) or DNA polymerase δ (cdc6), but not DNA replication initiation mutants. The ability of Pap1 to confer resistance to DNA damage was not specific to chk1 mutants, as it also improved survival of rad1- and rad9-deficient cells in the presence of CPT. To confer resistance to DNA damage Pap1 must localize to the nucleus and be transcriptionally active.
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Affiliation(s)
- Carrie Belfield
- Department of Pharmacology, Rutgers Robert Wood Johnson Medical School, Piscataway, New Jersey, United States of America
- Graduate Program in Cellular and Molecular Pharmacology, Rutgers Graduate School of Biomedical Sciences, Piscataway, New Jersey, United States of America
| | - Craig Queenan
- Department of Pharmacology, Rutgers Robert Wood Johnson Medical School, Piscataway, New Jersey, United States of America
| | - Hui Rao
- Department of Pharmacology, Rutgers Robert Wood Johnson Medical School, Piscataway, New Jersey, United States of America
| | - Kenji Kitamura
- Center for Gene Science, Hiroshima University, Higashi-Hiroshima, Japan
| | - Nancy C. Walworth
- Department of Pharmacology, Rutgers Robert Wood Johnson Medical School, Piscataway, New Jersey, United States of America
- Graduate Program in Cellular and Molecular Pharmacology, Rutgers Graduate School of Biomedical Sciences, Piscataway, New Jersey, United States of America
- Member, Rutgers Cancer Institute of New Jersey, New Brunswick, New Jersey, United States of America
- * E-mail:
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