1
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Zhang C, Liu J, Wu J, Ranjan K, Cui X, Wang X, Zhang D, Zhu S. Key molecular DNA damage responses of human cells to radiation. Front Cell Dev Biol 2024; 12:1422520. [PMID: 39050891 PMCID: PMC11266142 DOI: 10.3389/fcell.2024.1422520] [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] [Received: 04/24/2024] [Accepted: 06/19/2024] [Indexed: 07/27/2024] Open
Abstract
Our understanding of the DNA damage responses of human cells to radiation has increased remarkably over the recent years although some notable signaling events remain to be discovered. Here we provide a brief account of the key molecular events of the responses to reflect the current understanding of the key underlying mechanisms involved.
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Affiliation(s)
- Chencheng Zhang
- Cancer Research Center, Nantong Tumor Hospital, Nantong, China
- Cancer Research Institute, The Affiliated Tumor Hospital of Nantong University, Nantong, China
- Cancer Research Center, Nantong, China
| | - Jibin Liu
- Cancer Research Center, Nantong Tumor Hospital, Nantong, China
- Cancer Research Institute, The Affiliated Tumor Hospital of Nantong University, Nantong, China
- Cancer Research Center, Nantong, China
| | - Jun Wu
- Nantong Tumor Hospital, Nantong, China
| | - Kamakshi Ranjan
- Department of Bio-Medical Sciences, Philadelphia College of Osteopathic Medicine, Philadelphia, PA, United States
| | - Xiaopeng Cui
- Department of General Surgery, The Affiliated Hospital of Nantong University, Nantong, China
| | - Xingdan Wang
- Department of Radiotherapy, Nantong Tumor Hospital, The Affiliated Tumor Hospital of Nantong University, Nantong, China
| | - Dianzheng Zhang
- Department of Bio-Medical Sciences, Philadelphia College of Osteopathic Medicine, Philadelphia, PA, United States
| | - Shudong Zhu
- Cancer Research Center, Nantong Tumor Hospital, Nantong, China
- Cancer Research Institute, The Affiliated Tumor Hospital of Nantong University, Nantong, China
- Cancer Research Center, Nantong, China
- Argus Pharmaceuticals, Changsha, China
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2
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Li P, Yu X. The role of rRNA in maintaining genome stability. DNA Repair (Amst) 2024; 139:103692. [PMID: 38759435 DOI: 10.1016/j.dnarep.2024.103692] [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: 03/25/2024] [Revised: 05/06/2024] [Accepted: 05/06/2024] [Indexed: 05/19/2024]
Abstract
Over the past few decades, unbiased approaches such as genetic screening and protein affinity purification have unveiled numerous proteins involved in DNA double-strand break (DSB) repair and maintaining genome stability. However, despite our knowledge of these protein factors, the underlying molecular mechanisms governing key cellular events during DSB repair remain elusive. Recent evidence has shed light on the role of non-protein factors, such as RNA, in several pivotal steps of DSB repair. In this review, we provide a comprehensive summary of these recent findings, highlighting the significance of ribosomal RNA (rRNA) as a critical mediator of DNA damage response, meiosis, and mitosis. Moreover, we discuss potential mechanisms through which rRNA may influence genome integrity.
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Affiliation(s)
- Peng Li
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China; School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China; Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China
| | - Xiaochun Yu
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China; School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China; Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China.
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3
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Ascenção C, Sims JR, Dziubek A, Comstock W, Fogarty EA, Badar J, Freire R, Grimson A, Weiss RS, Cohen PE, Smolka MB. A TOPBP1 allele causing male infertility uncouples XY silencing dynamics from sex body formation. eLife 2024; 12:RP90887. [PMID: 38391183 PMCID: PMC10942628 DOI: 10.7554/elife.90887] [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] [Indexed: 02/24/2024] Open
Abstract
Meiotic sex chromosome inactivation (MSCI) is a critical feature of meiotic prophase I progression in males. While the ATR kinase and its activator TOPBP1 are key drivers of MSCI within the specialized sex body (SB) domain of the nucleus, how they promote silencing remains unclear given their multifaceted meiotic functions that also include DNA repair, chromosome synapsis, and SB formation. Here we report a novel mutant mouse harboring mutations in the TOPBP1-BRCT5 domain. Topbp1B5/B5 males are infertile, with impaired MSCI despite displaying grossly normal events of early prophase I, including synapsis and SB formation. Specific ATR-dependent events are disrupted, including phosphorylation and localization of the RNA:DNA helicase Senataxin. Topbp1B5/B5 spermatocytes initiate, but cannot maintain ongoing, MSCI. These findings reveal a non-canonical role for the ATR-TOPBP1 signaling axis in MSCI dynamics at advanced stages in pachynema and establish the first mouse mutant that separates ATR signaling and MSCI from SB formation.
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Affiliation(s)
- Carolline Ascenção
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell UniversityIthacaUnited States
| | - Jennie R Sims
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell UniversityIthacaUnited States
| | - Alexis Dziubek
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell UniversityIthacaUnited States
| | - William Comstock
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell UniversityIthacaUnited States
| | - Elizabeth A Fogarty
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell UniversityIthacaUnited States
| | - Jumana Badar
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell UniversityIthacaUnited States
| | - Raimundo Freire
- Fundación Canaria del Instituto de Investigación Sanitaria de Canarias (FIISC), Unidad de Investigación, Hospital Universitario de CanariasSanta Cruz de TenerifeSpain
- Instituto de Tecnologías Biomédicas, Universidad de La LagunaLa LagunaSpain
- Universidad Fernando Pessoa CanariasLas Palmas de Gran CanariaSpain
| | - Andrew Grimson
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell UniversityIthacaUnited States
| | - Robert S Weiss
- Department of Biomedical Sciences, Cornell UniversityIthacaUnited States
| | - Paula E Cohen
- Department of Biomedical Sciences, Cornell UniversityIthacaUnited States
| | - Marcus B Smolka
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell UniversityIthacaUnited States
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4
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Kumar V, Chunchagatta Lakshman PK, Prasad TK, Manjunath K, Bairy S, Vasu AS, Ganavi B, Jasti S, Kamariah N. Target-based drug discovery: Applications of fluorescence techniques in high throughput and fragment-based screening. Heliyon 2024; 10:e23864. [PMID: 38226204 PMCID: PMC10788520 DOI: 10.1016/j.heliyon.2023.e23864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 12/14/2023] [Accepted: 12/14/2023] [Indexed: 01/17/2024] Open
Abstract
Target-based discovery of first-in-class therapeutics demands an in-depth understanding of the molecular mechanisms underlying human diseases. Precise measurements of cellular and biochemical activities are critical to gain mechanistic knowledge of biomolecules and their altered function in disease conditions. Such measurements enable the development of intervention strategies for preventing or treating diseases by modulation of desired molecular processes. Fluorescence-based techniques are routinely employed for accurate and robust measurements of in-vitro activity of molecular targets and for discovering novel chemical molecules that modulate the activity of molecular targets. In the current review, the authors focus on the applications of fluorescence-based high throughput screening (HTS) and fragment-based ligand discovery (FBLD) techniques such as fluorescence polarization (FP), Förster resonance energy transfer (FRET), fluorescence thermal shift assay (FTSA) and microscale thermophoresis (MST) for the discovery of chemical probe to exploring target's role in disease biology and ultimately, serve as a foundation for drug discovery. Some recent advancements in these techniques for compound library screening against important classes of drug targets, such as G-protein-coupled receptors (GPCRs) and GTPases, as well as phosphorylation- and acetylation-mediated protein-protein interactions, are discussed. Overall, this review presents a landscape of how these techniques paved the way for the discovery of small-molecule modulators and biologics against these targets for therapeutic benefits.
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Affiliation(s)
| | | | - Thazhe Kootteri Prasad
- Centre for Chemical Biology & Therapeutics, inStem & NCBS, Bellary Road, Bangalore, 560065, India
| | - Kavyashree Manjunath
- Centre for Chemical Biology & Therapeutics, inStem & NCBS, Bellary Road, Bangalore, 560065, India
| | - Sneha Bairy
- Centre for Chemical Biology & Therapeutics, inStem & NCBS, Bellary Road, Bangalore, 560065, India
| | - Akshaya S. Vasu
- Centre for Chemical Biology & Therapeutics, inStem & NCBS, Bellary Road, Bangalore, 560065, India
| | - B. Ganavi
- Centre for Chemical Biology & Therapeutics, inStem & NCBS, Bellary Road, Bangalore, 560065, India
| | - Subbarao Jasti
- Centre for Chemical Biology & Therapeutics, inStem & NCBS, Bellary Road, Bangalore, 560065, India
| | - Neelagandan Kamariah
- Centre for Chemical Biology & Therapeutics, inStem & NCBS, Bellary Road, Bangalore, 560065, India
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5
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Ascencao CFR, Sims JR, Dziubek A, Comstock W, Fogarty EA, Badar J, Freire R, Grimson A, Weiss RS, Cohen PE, Smolka M. A TOPBP1 Allele Causing Male Infertility Uncouples XY Silencing Dynamics From Sex Body Formation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.31.543071. [PMID: 37398453 PMCID: PMC10312512 DOI: 10.1101/2023.05.31.543071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Meiotic sex chromosome inactivation (MSCI) is a critical feature of meiotic prophase I progression in males. While the ATR kinase and its activator TOPBP1 are key drivers of MSCI within the specialized sex body (SB) domain of the nucleus, how they promote silencing remains unclear given their multifaceted meiotic functions that also include DNA repair, chromosome synapsis and SB formation. Here we report a novel mutant mouse harboring mutations in the TOPBP1-BRCT5 domain. Topbp1 B5/B5 males are infertile, with impaired MSCI despite displaying grossly normal events of early prophase I, including synapsis and SB formation. Specific ATR-dependent events are disrupted including phosphorylation and localization of the RNA:DNA helicase Senataxin. Topbp1 B5/B5 spermatocytes initiate, but cannot maintain ongoing, MSCI. These findings reveal a non-canonical role for the ATR-TOPBP1 signaling axis in MSCI dynamics at advanced stages in pachynema and establish the first mouse mutant that separates ATR signaling and MSCI from SB formation.
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6
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Wu D, Huang H, Chen T, Gai X, Li Q, Wang C, Yao J, Liu Y, Cai S, Yu X. The BRCA1/BARD1 complex recognizes pre-ribosomal RNA to facilitate homologous recombination. Cell Discov 2023; 9:99. [PMID: 37789001 PMCID: PMC10547766 DOI: 10.1038/s41421-023-00590-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 07/16/2023] [Indexed: 10/05/2023] Open
Abstract
The BRCA1/BARD1 complex plays a key role in the repair of DNA double-strand breaks (DSBs) in both somatic cells and germ cells. However, the underlying molecular mechanism by which this complex mediates DSB repair is not fully understood. Here, we examined the XY body of male germ cells, where DSBs are accumulated. We show that the recruitment of the BRCA1/BARD1 complex to the unsynapsed axis of the XY body is mediated by pre-ribosomal RNA (pre-rRNA). Similarly, the BRCA1/BARD1 complex associates with pre-rRNA in somatic cells, which not only forms nuclear foci in response to DSBs, but also targets the BRCA1/BARD1 complex to DSBs. The interactions between the BRCT domains of the BRCA1/BARD1 complex and pre-rRNA induce liquid-liquid phase separations, which may be the molecular basis of DSB-induced nuclear foci formation of the BRCA1/BARD1 complex. Moreover, cancer-associated mutations in the BRCT domains of BRCA1 and BARD1 abolish their interactions with pre-rRNA. Pre-rRNA also mediates BRCA1-dependent homologous recombination, and suppression of pre-rRNA biogenesis sensitizes cells to PARP inhibitor treatment. Collectively, this study reveals that pre-rRNA is a functional partner of the BRCA1/BARD1 complex in the DSB repair.
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Affiliation(s)
- Duo Wu
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China
- School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China
- Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China
| | - Huang Huang
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China
- School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China
- Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China
| | - Tenglong Chen
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China
- School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China
- Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China
| | - Xiaochen Gai
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China
- School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China
- Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China
| | - Qilin Li
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China
- School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China
- Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China
| | - Chunhui Wang
- School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China
- Westlake Disease Modeling Lab, Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China
- Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China
| | - Jia Yao
- The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Yu Liu
- The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Shang Cai
- School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China
- Westlake Disease Modeling Lab, Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China
- Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China
| | - Xiaochun Yu
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China.
- School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China.
- Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China.
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7
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Xin D, Gai X, Ma Y, Li Z, Li Q, Yu X. Pre-rRNA Facilitates TopBP1-Mediated DNA Double-Strand Break Response. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2206931. [PMID: 37582658 PMCID: PMC10558638 DOI: 10.1002/advs.202206931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 06/28/2023] [Indexed: 08/17/2023]
Abstract
In response to genotoxic stress-induced DNA damage, TopBP1 mediates ATR activation for signaling transduction and DNA damage repair. However, the detailed molecular mechanism remains elusive. Here, using unbiased protein affinity purification and RNA sequencing, it is found that TopBP1 is associated with pre-ribosomal RNA (pre-rRNA). Pre-rRNA co-localized with TopBP1 at DNA double-strand breaks (DSBs). Similar to pre-rRNA, ribosomal proteins also colocalize with TopBP1 at DSBs. The recruitment of TopBP1 to DSBs is suppressed when cells are transiently treated with RNA polymerase I inhibitor (Pol I-i) to suppress pre-rRNA biogenesis but not protein translation. Moreover, the BRCT4-5 of TopBP1 recognizes pre-rRNA and forms liquid-liquid phase separation (LLPS) with pre-rRNA, which may be the molecular basis of DSB-induced foci of TopBP1. Finally, Pol I-i treatment impairs TopBP1-associated cell cycle checkpoint activation and homologous recombination repair. Collectively, this study reveals that pre-rRNA plays a key role in the TopBP1-dependent DNA damage response.
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Affiliation(s)
- Di Xin
- School of Life SciencesWestlake UniversityHangzhouZhejiang310024China
- Department of Hepatobiliary and Pancreatic Surgery and Zhejiang Provincial Key Laboratory of Pancreatic DiseaseThe First Affiliated HospitalZhejiang University School of MedicineHangzhouZhejiang310003China
- Westlake Laboratory of Life Sciences and BiomedicineHangzhouZhejiang310024China
- Institute of Basic Medical SciencesWestlake Institute for Advanced StudyHangzhouZhejiang310024China
| | - Xiaochen Gai
- School of Life SciencesWestlake UniversityHangzhouZhejiang310024China
- Westlake Laboratory of Life Sciences and BiomedicineHangzhouZhejiang310024China
- Institute of Basic Medical SciencesWestlake Institute for Advanced StudyHangzhouZhejiang310024China
| | - Yidi Ma
- School of Life SciencesWestlake UniversityHangzhouZhejiang310024China
- Westlake Laboratory of Life Sciences and BiomedicineHangzhouZhejiang310024China
- Institute of Basic Medical SciencesWestlake Institute for Advanced StudyHangzhouZhejiang310024China
| | - Zexing Li
- School of Life SciencesTianjin UniversityTianjin300072China
| | - Qilin Li
- School of Life SciencesWestlake UniversityHangzhouZhejiang310024China
- Westlake Laboratory of Life Sciences and BiomedicineHangzhouZhejiang310024China
- Institute of Basic Medical SciencesWestlake Institute for Advanced StudyHangzhouZhejiang310024China
| | - Xiaochun Yu
- School of Life SciencesWestlake UniversityHangzhouZhejiang310024China
- Westlake Laboratory of Life Sciences and BiomedicineHangzhouZhejiang310024China
- Institute of Basic Medical SciencesWestlake Institute for Advanced StudyHangzhouZhejiang310024China
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8
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Zhong AX, Chen Y, Chen PL. BRCA1 the Versatile Defender: Molecular to Environmental Perspectives. Int J Mol Sci 2023; 24:14276. [PMID: 37762577 PMCID: PMC10532398 DOI: 10.3390/ijms241814276] [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: 08/17/2023] [Revised: 09/13/2023] [Accepted: 09/14/2023] [Indexed: 09/29/2023] Open
Abstract
The evolving history of BRCA1 research demonstrates the profound interconnectedness of a single protein within the web of crucial functions in human cells. Mutations in BRCA1, a tumor suppressor gene, have been linked to heightened breast and ovarian cancer risks. However, despite decades of extensive research, the mechanisms underlying BRCA1's contribution to tissue-specific tumor development remain elusive. Nevertheless, much of the BRCA1 protein's structure, function, and interactions has been elucidated. Individual regions of BRCA1 interact with numerous proteins to play roles in ubiquitination, transcription, cell checkpoints, and DNA damage repair. At a cellular scale, these BRCA1 functions coordinate tumor suppression, R-loop prevention, and cellular differentiation, all of which may contribute to BRCA1's role in cancer tissue specificity. As research on BRCA1 and breast cancer continues to evolve, it will become increasingly evident that modern materials such as Bisphenol A should be examined for their relationship with DNA stability, cancer incidence, and chemotherapy. Overall, this review offers a comprehensive understanding of BRCA1's many roles at a molecular, cellular, organismal, and environmental scale. We hope that the knowledge gathered here highlights both the necessity of BRCA1 research and the potential for novel strategies to prevent and treat cancer in individuals carrying BRCA1 mutations.
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Affiliation(s)
- Amy X. Zhong
- Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA;
| | - Yumay Chen
- Department of Medicine, Division of Endocrinology, University of California, Irvine, CA 92697, USA;
| | - Phang-Lang Chen
- Department of Biological Chemistry, University of California, Irvine, CA 92697, USA
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9
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Regulation of DNA damage response by trimeric G-proteins. iScience 2023; 26:105973. [PMID: 36756378 PMCID: PMC9900518 DOI: 10.1016/j.isci.2023.105973] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 08/14/2022] [Accepted: 01/10/2023] [Indexed: 01/14/2023] Open
Abstract
Upon sensing DNA double-strand breaks (DSBs), eukaryotic cells either die or repair DSBs via one of the two competing pathways, i.e., non-homologous end-joining (NHEJ) or homologous recombination (HR). We show that cell fate after DSBs hinges on GIV/Girdin, a guanine nucleotide-exchange modulator of heterotrimeric Giα•βγ protein. GIV suppresses HR by binding and sequestering BRCA1, a key coordinator of multiple steps within the HR pathway, away from DSBs; it does so using a C-terminal motif that binds BRCA1's BRCT-modules via both phospho-dependent and -independent mechanisms. Using another non-overlapping C-terminal motif GIV binds and activates Gi and enhances the "free" Gβγ→PI-3-kinase→Akt pathway, which promotes survival and is known to suppress HR, favor NHEJ. Absence of GIV, or loss of either of its C-terminal motifs enhanced cell death upon genotoxic stress. Because GIV selectively binds other BRCT-containing proteins suggests that G-proteins may fine-tune sensing, repair, and survival after diverse types of DNA damage.
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10
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Park D, Gharghabi M, Reczek CR, Plow R, Yungvirt C, Aldaz CM, Huebner K. Wwox Binding to the Murine Brca1-BRCT Domain Regulates Timing of Brip1 and CtIP Phospho-Protein Interactions with This Domain at DNA Double-Strand Breaks, and Repair Pathway Choice. Int J Mol Sci 2022; 23:ijms23073729. [PMID: 35409089 PMCID: PMC8999063 DOI: 10.3390/ijms23073729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 03/21/2022] [Accepted: 03/24/2022] [Indexed: 11/16/2022] Open
Abstract
Wwox-deficient human cells show elevated homologous recombination, leading to resistance to killing by double-strand break-inducing agents. Human Wwox binds to the Brca1 981-PPLF-984 Wwox-binding motif, likely blocking the pChk2 phosphorylation site at Brca1-S988. This phosphorylation site is conserved across mammalian species; the PPLF motif is conserved in primates but not in rodents. We now show that murine Wwox does not bind Brca1 near the conserved mouse Brca1 phospho-S971 site, leaving it open for Chk2 phosphorylation and Brca1 activation. Instead, murine Wwox binds to Brca1 through its BRCT domain, where pAbraxas, pBrip1, and pCtIP, of the A, B, and C binding complexes, interact to regulate double-strand break repair pathway response. In Wwox-deficient mouse cells, the Brca1-BRCT domain is thus accessible for immediate binding of these phospho-proteins. We confirm elevated homologous recombination in Wwox-silenced murine cells, as in human cells. Wwox-deficient murine cells showed increased ionizing radiation-induced Abraxas, Brca1, and CtIP foci and long resected single-strand DNA, early after ionizing radiation. Wwox deletion increased the basal level of Brca1-CtIP interaction and the expression level of the MRN-CtIP protein complex, key players in end-resection, and facilitated Brca1 release from foci. Inhibition of phospho-Chk2 phosphorylation of Brca1-S971 delays the end-resection; the delay of premature end-resection by combining Chk2 inhibition with ionizing radiation or carboplatin treatment restored ionizing radiation and platinum sensitivity in Wwox-deficient murine cells, as in human cells, supporting the use of murine in vitro and in vivo models in preclinical cancer treatment research.
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Affiliation(s)
- Dongju Park
- Department of Cancer Biology and Genetics, The Comprehensive Cancer Center, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA; (M.G.); (R.P.); (C.Y.)
- Correspondence: (D.P.); (K.H.); Tel.: +1-614-685-9124 (D.P.); +1-614-292-4850 (K.H.)
| | - Mehdi Gharghabi
- Department of Cancer Biology and Genetics, The Comprehensive Cancer Center, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA; (M.G.); (R.P.); (C.Y.)
- Department of Outcomes and Translational Sciences, College of Pharmacy, The Ohio State University, Columbus, OH 43210, USA
| | - Colleen R. Reczek
- Department of Pathology & Cell Biology, Columbia University Irving Medical Center, Columbia University, New York, NY 10032, USA;
| | - Rebecca Plow
- Department of Cancer Biology and Genetics, The Comprehensive Cancer Center, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA; (M.G.); (R.P.); (C.Y.)
| | - Charles Yungvirt
- Department of Cancer Biology and Genetics, The Comprehensive Cancer Center, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA; (M.G.); (R.P.); (C.Y.)
| | - C. Marcelo Aldaz
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, 1881 East Road, Houston, TX 77054, USA;
| | - Kay Huebner
- Department of Cancer Biology and Genetics, The Comprehensive Cancer Center, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA; (M.G.); (R.P.); (C.Y.)
- Correspondence: (D.P.); (K.H.); Tel.: +1-614-685-9124 (D.P.); +1-614-292-4850 (K.H.)
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11
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Kliche J, Ivarsson Y. Orchestrating serine/threonine phosphorylation and elucidating downstream effects by short linear motifs. Biochem J 2022; 479:1-22. [PMID: 34989786 PMCID: PMC8786283 DOI: 10.1042/bcj20200714] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 12/16/2021] [Accepted: 12/20/2021] [Indexed: 12/13/2022]
Abstract
Cellular function is based on protein-protein interactions. A large proportion of these interactions involves the binding of short linear motifs (SLiMs) by folded globular domains. These interactions are regulated by post-translational modifications, such as phosphorylation, that create and break motif binding sites or tune the affinity of the interactions. In addition, motif-based interactions are involved in targeting serine/threonine kinases and phosphatases to their substrate and contribute to the specificity of the enzymatic actions regulating which sites are phosphorylated. Here, we review how SLiM-based interactions assist in determining the specificity of serine/threonine kinases and phosphatases, and how phosphorylation, in turn, affects motif-based interactions. We provide examples of SLiM-based interactions that are turned on/off, or are tuned by serine/threonine phosphorylation and exemplify how this affects SLiM-based protein complex formation.
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Affiliation(s)
- Johanna Kliche
- Department of Chemistry – BMC, Uppsala University, Husargatan 3, Box 576 751 23 Uppsala, Sweden
| | - Ylva Ivarsson
- Department of Chemistry – BMC, Uppsala University, Husargatan 3, Box 576 751 23 Uppsala, Sweden
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12
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Abd El-hafeez AA, Sun N, Chakraborty A, Ear J, Roy S, Chamarthi P, Rajapakse N, Das S, Luker KE, Hazra TK, Luker GD, Ghosh P. Regulation of DNA damage response by trimeric G-protein Signaling.. [DOI: 10.1101/2021.07.21.452842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
Abstract
AbstractUpon sensing DNA double-strand breaks (DSBs), eukaryotic cells either die or repair DSBs via one of two competing pathways, i.e., non-homologous end-joining (NHEJ) or homologous recombination (HR). We show that cell fate after DNA damage hinges on the guanine nucleotide-exchange modulator of heterotrimeric G-protein, Giα•βγ, GIV/Girdin. GIV suppresses HR by binding and sequestering BRCA1, a key coordinator of multiple steps within the HR pathway, away from DSBs; it does so using a C-terminal motif that binds BRCA1’s BRCT-modules via both phospho-dependent and -independent mechanisms. GIV promotes NHEJ, and binds and activates Gi and enhances the ‘free’ Gβγ→PI-3-kinase→Akt pathway, thus revealing the enigmatic origin of prosurvival Akt signals during dsDNA repair. Absence of GIV, or the loss of either of its two functions impaired DNA repair, and induced cell death when challenged with numerous cytotoxic agents. That GIV selectively binds few other BRCT-containing proteins suggests convergent signaling such that heterotrimeric G-proteins may finetune sensing, repair, and outcome after DNA damage.GRAPHIC ABSTRACTHIGHLIGHTSNon-receptor G protein modulator, GIV/Girdin binds BRCA1Binding occurs in both canonical and non-canonical modesGIV sequesters BRCA1 away from dsDNA breaks, suppresses HRActivation of Gi by GIV enhances Akt signals, favors NHEJIN BRIEFIn this work, the authors show that heterotrimeric G protein signaling that is triggered by non-receptor GEF, GIV/Girdin, in response to double-stranded DNA breaks is critical for decisive signaling events which favor non-homologous end-joining (NHEJ) and inhibit homologous recombination (HR).
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Williams RM, Zhang X. Roles of ATM and ATR in DNA double strand breaks and replication stress. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2021; 161:27-38. [DOI: 10.1016/j.pbiomolbio.2020.11.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 11/17/2020] [Accepted: 11/25/2020] [Indexed: 12/22/2022]
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Li Q, Engebrecht J. BRCA1 and BRCA2 Tumor Suppressor Function in Meiosis. Front Cell Dev Biol 2021; 9:668309. [PMID: 33996823 PMCID: PMC8121103 DOI: 10.3389/fcell.2021.668309] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 03/19/2021] [Indexed: 12/12/2022] Open
Abstract
Meiosis is a specialized cell cycle that results in the production of haploid gametes for sexual reproduction. During meiosis, homologous chromosomes are connected by chiasmata, the physical manifestation of crossovers. Crossovers are formed by the repair of intentionally induced double strand breaks by homologous recombination and facilitate chromosome alignment on the meiotic spindle and proper chromosome segregation. While it is well established that the tumor suppressors BRCA1 and BRCA2 function in DNA repair and homologous recombination in somatic cells, the functions of BRCA1 and BRCA2 in meiosis have received less attention. Recent studies in both mice and the nematode Caenorhabditis elegans have provided insight into the roles of these tumor suppressors in a number of meiotic processes, revealing both conserved and organism-specific functions. BRCA1 forms an E3 ubiquitin ligase as a heterodimer with BARD1 and appears to have regulatory roles in a number of key meiotic processes. BRCA2 is a very large protein that plays an intimate role in homologous recombination. As women with no indication of cancer but carrying BRCA mutations show decreased ovarian reserve and accumulated oocyte DNA damage, studies in these systems may provide insight into why BRCA mutations impact reproductive success in addition to their established roles in cancer.
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Affiliation(s)
- Qianyan Li
- Department of Molecular and Cellular Biology, and Biochemistry, Molecular, Cellular and Developmental Biology Graduate Group, University of California, Davis, Davis, CA, United States
| | - JoAnne Engebrecht
- Department of Molecular and Cellular Biology, and Biochemistry, Molecular, Cellular and Developmental Biology Graduate Group, University of California, Davis, Davis, CA, United States
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15
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Roles of ATM and ATR in DNA double strand breaks and replication stress. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2021; 163:109-119. [PMID: 33887296 DOI: 10.1016/j.pbiomolbio.2021.03.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 11/17/2020] [Accepted: 11/25/2020] [Indexed: 02/06/2023]
Abstract
The maintenance of genome integrity is critical for the faithful replication of the genome during cell division and for protecting cells from accumulation of DNA damage, which if left unrepaired leads to a loss of genetic information, a breakdown in cell function and ultimately cell death and cancer. ATM and ATR are master kinases that are integral to homologous recombination-mediated repair of double strand breaks and preventing accumulation of dangerous DNA structures and genome instability during replication stress. While the roles of ATM and ATR are heavily intertwined in response to double strand breaks, their roles diverge in the response to replication stress. This review summarises our understanding of the players and their mode of actions in recruitment, activation and activity of ATM and ATR in response to DNA damage and replication stress and discusses how controlling localisation of these kinases and their activators allows them to orchestrate a stress-specific response.
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16
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Activation of DNA damage response signaling in mammalian cells by ionizing radiation. Free Radic Res 2021; 55:581-594. [PMID: 33455476 DOI: 10.1080/10715762.2021.1876853] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Cellular responses to DNA damage are fundamental to preserve genomic integrity during various endogenous and exogenous stresses. Following radiation therapy and chemotherapy, this DNA damage response (DDR) also determines development of carcinogenesis and therapeutic outcome. In humans, DNA damage activates a robust network of signal transduction cascades, driven primarily through phosphorylation events. These responses primarily involve two key non-redundant signal transducing proteins of phosphatidylinositol 3-kinase-like (PIKK) family - ATR and ATM, and their downstream kinases (hChk1 and hChk2). They further phosphorylate effectors proteins such as p53, Cdc25A and Cdc25C which function either to activate the DNA damage checkpoints and cell death mechanisms, or DNA repair pathways. Identification of molecular pathways that determine signaling after DNA damage and trigger DNA repair in response to differing types of DNA lesions allows for a far better understanding of the consequences of radiation and chemotherapy on normal and tumor cells. Here we highlight the network of DNA damage response pathways that are activated after treatment with different types of radiation. Further, we discuss regulation of cell cycle checkpoint and DNA repair processes in the context of DDR in response to radiation.
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Zhang J, Yan Z, Wang Y, Wang Y, Guo X, Jing J, Dong X, Dong S, Liu X, Yu X, Wu C. Cancer-associated 53BP1 mutations induce DNA damage repair defects. Cancer Lett 2020; 501:43-54. [PMID: 33359708 DOI: 10.1016/j.canlet.2020.12.033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 12/18/2020] [Accepted: 12/21/2020] [Indexed: 12/29/2022]
Abstract
TP53 binding protein 1 (53BP1) plays an important role in DNA damage repair and maintaining genomic stability. However, the mutations of 53BP1 in human cancers have not been systematically examined. Here, we have analyzed 541 somatic mutations of 53BP1 across 34 types of human cancer from databases of The Cancer Genome Atlas, International Cancer Genome Consortium and Catalogue of Somatic Mutations in Cancer. Among these cancer-associated 53BP1 mutations, truncation mutations disrupt the nuclear localization of 53BP1 thus abolish its biological functions in DNA damage repair. Moreover, with biochemical analyses and structural modeling, we have examined the detailed molecular mechanism by which missense mutations in the key domains causes the DNA damage repair defects. Taken together, our results reveal the functional defects of a set of cancer-associated 53BP1 mutations.
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Affiliation(s)
- Jiajia Zhang
- School of Life Sciences, Institute of Life Sciences and Green Development, Hebei University, Baoding, 071002, Hebei, China
| | - Zhenzhen Yan
- School of Life Sciences, Institute of Life Sciences and Green Development, Hebei University, Baoding, 071002, Hebei, China
| | - Yukun Wang
- School of Life Sciences, Institute of Life Sciences and Green Development, Hebei University, Baoding, 071002, Hebei, China
| | - Yaguang Wang
- School of Life Sciences, Institute of Life Sciences and Green Development, Hebei University, Baoding, 071002, Hebei, China
| | - Xin Guo
- School of Life Sciences, Institute of Life Sciences and Green Development, Hebei University, Baoding, 071002, Hebei, China
| | - Ju Jing
- School of Life Sciences, Institute of Life Sciences and Green Development, Hebei University, Baoding, 071002, Hebei, China
| | - Xiangnan Dong
- School of Life Sciences, Institute of Life Sciences and Green Development, Hebei University, Baoding, 071002, Hebei, China
| | - Shasha Dong
- School of Life Sciences, Institute of Life Sciences and Green Development, Hebei University, Baoding, 071002, Hebei, China
| | - Xiuhua Liu
- School of Life Sciences, Institute of Life Sciences and Green Development, Hebei University, Baoding, 071002, Hebei, China.
| | - Xiaochun Yu
- School of Life Sciences, Westlake University, Hangzhou, Zhejiang, 310024, China.
| | - Chen Wu
- School of Life Sciences, Institute of Life Sciences and Green Development, Hebei University, Baoding, 071002, Hebei, China.
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18
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p50 mono-ubiquitination and interaction with BARD1 regulates cell cycle progression and maintains genome stability. Nat Commun 2020; 11:5007. [PMID: 33024116 PMCID: PMC7538584 DOI: 10.1038/s41467-020-18838-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 09/15/2020] [Indexed: 01/14/2023] Open
Abstract
p50, the mature product of NFKB1, is constitutively produced from its precursor, p105. Here, we identify BARD1 as a p50-interacting factor. p50 directly associates with the BARD1 BRCT domains via a C-terminal phospho-serine motif. This interaction is induced by ATR and results in mono-ubiquitination of p50 by the BARD1/BRCA1 complex. During the cell cycle, p50 is mono-ubiquitinated in S phase and loss of this post-translational modification increases S phase progression and chromosomal breakage. Genome-wide studies reveal a substantial decrease in p50 chromatin enrichment in S phase and Cycln E is identified as a factor regulated by p50 during the G1 to S transition. Functionally, interaction with BARD1 promotes p50 protein stability and consistent with this, in human cancer specimens, low nuclear BARD1 protein strongly correlates with low nuclear p50. These data indicate that p50 mono-ubiquitination by BARD1/BRCA1 during the cell cycle regulates S phase progression to maintain genome integrity. p50 is a constitutively produced NF-κB subunit that modulates the response to DNA damage. Here, the authors show that activation of ATR during S phase induces p50 interaction with BARD1 resulting in p50 mono-ubiquitination, facilitating cell cycle progression and promoting chromosome integrity.
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Sadeghi F, Asgari M, Matloubi M, Ranjbar M, Karkhaneh Yousefi N, Azari T, Zaki-Dizaji M. Molecular contribution of BRCA1 and BRCA2 to genome instability in breast cancer patients: review of radiosensitivity assays. Biol Proced Online 2020; 22:23. [PMID: 33013205 PMCID: PMC7528506 DOI: 10.1186/s12575-020-00133-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 08/04/2020] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND DNA repair pathways, cell cycle arrest checkpoints, and cell death induction are present in cells to process DNA damage and prevent genomic instability caused by various extrinsic and intrinsic ionizing factors. Mutations in the genes involved in these pathways enhances the ionizing radiation sensitivity, reduces the individual's capacity to repair DNA damages, and subsequently increases susceptibility to tumorigenesis. BODY BRCA1 and BRCA2 are two highly penetrant genes involved in the inherited breast cancer and contribute to different DNA damage pathways and cell cycle and apoptosis cascades. Mutations in these genes have been associated with hypersensitivity and genetic instability as well as manifesting severe radiotherapy complications in breast cancer patients. The genomic instability and DNA repair capacity of breast cancer patients with BRCA1/2 mutations have been analyzed in different studies using a variety of assays, including micronucleus assay, comet assay, chromosomal assay, colony-forming assay, γ -H2AX and 53BP1 biomarkers, and fluorescence in situ hybridization. The majority of studies confirmed the enhanced spontaneous & radiation-induced radiosensitivity of breast cancer patients compared to healthy controls. Using G2 micronucleus assay and G2 chromosomal assay, most studies have reported the lymphocyte of healthy carriers with BRCA1 mutation are hypersensitive to invitro ionizing radiation compared to non-carriers without a history of breast cancer. However, it seems this approach is not likely to be useful to distinguish the BRCA carriers from non-carrier with familial history of breast cancer. CONCLUSION In overall, breast cancer patients are more radiosensitive compared to healthy control; however, inconsistent results exist about the ability of current radiosensitive techniques in screening BRCA1/2 carriers or those susceptible to radiotherapy complications. Therefore, developing further radiosensitivity assay is still warranted to evaluate the DNA repair capacity of individuals with BRCA1/2 mutations and serve as a predictive factor for increased risk of cancer mainly in the relatives of breast cancer patients. Moreover, it can provide more evidence about who is susceptible to manifest severe complication after radiotherapy.
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Affiliation(s)
- Fatemeh Sadeghi
- Department of Immunology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
- Digestive Diseases Research Institute, Digestive Oncology Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Marzieh Asgari
- Rheumatology Research Center, Tehran University of Medical Sciences, Shariati Hospital, Kargar Ave, Tehran, Iran
| | - Mojdeh Matloubi
- Department of Immunology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Maral Ranjbar
- Department of Immunology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Nahid Karkhaneh Yousefi
- Cancer Research Center, Cancer Institute of Iran, Tehran University of Medical Sciences, Tehran, Iran
| | - Tahereh Azari
- Department of Immunology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Majid Zaki-Dizaji
- Legal Medicine Research Center, Legal Medicine Organization, Tehran, Iran
- Research Center for Immunodeficiencies, Children’s Medical Center, Tehran University of Medical Sciences, Tehran, Iran
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20
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Bagge J, Oestergaard VH, Lisby M. Functions of TopBP1 in preserving genome integrity during mitosis. Semin Cell Dev Biol 2020; 113:57-64. [PMID: 32912640 DOI: 10.1016/j.semcdb.2020.08.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 07/06/2020] [Accepted: 08/26/2020] [Indexed: 12/20/2022]
Abstract
TopBP1/Rad4/Dpb11 is an essential eukaryotic protein with important roles in DNA replication, DNA repair, DNA damage checkpoint activation, and chromosome segregation. TopBP1 serves as a scaffold to assemble protein complexes in a phosphorylation-dependent manner via its multiple BRCT-repeats. Recently, it has become clear that TopBP1 is repurposed to scaffold different processes dependent on cell cycle regulated changes in phosphorylation of client proteins. Here we review the functions of human TopBP1 in maintaining genome integrity during mitosis.
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Affiliation(s)
- Jonas Bagge
- Department of Biology, University of Copenhagen, DK-2200 Copenhagen N, Denmark
| | - Vibe H Oestergaard
- Department of Biology, University of Copenhagen, DK-2200 Copenhagen N, Denmark
| | - Michael Lisby
- Department of Biology, University of Copenhagen, DK-2200 Copenhagen N, Denmark.
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21
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Park D, Bergin SM, Jones D, Ru P, Koivisto CS, Jeon YJ, Sizemore GM, Kladney RD, Hadjis A, Shakya R, Ludwig T. Ablation of the Brca1-Palb2 Interaction Phenocopies Fanconi Anemia in Mice. Cancer Res 2020; 80:4172-4184. [PMID: 32732220 DOI: 10.1158/0008-5472.can-20-0486] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 05/01/2020] [Accepted: 07/21/2020] [Indexed: 11/16/2022]
Abstract
Heterozygous mutations in the BRCA1 gene predispose women to breast and ovarian cancer, while biallelic BRCA1 mutations are a cause of Fanconi anemia (FA), a rare genetic disorder characterized by developmental abnormalities, early-onset bone marrow failure, increased risk of cancers, and hypersensitivity to DNA-crosslinking agents. BRCA1 is critical for homologous recombination of DNA double-strand breaks (DSB). Through its coiled-coil domain, BRCA1 interacts with an essential partner, PALB2, recruiting BRCA2 and RAD51 to sites of DNA damage. Missense mutations within the coiled-coil domain of BRCA1 (e.g., L1407P) that affect the interaction with PALB2 have been reported in familial breast cancer. We hypothesized that if PALB2 regulates or mediates BRCA1 tumor suppressor function, ablation of the BRCA1-PALB2 interaction may also elicit genomic instability and tumor susceptibility. We generated mice defective for the Brca1-Palb2 interaction (Brca1 L1363P in mice) and established MEF cells from these mice. Brca1 L1363P/L1363P MEF exhibited hypersensitivity to DNA-damaging agents and failed to recruit Rad51 to DSB. Brca1 L1363P/L1363P mice were viable but exhibited various FA symptoms including growth retardation, hyperpigmentation, skeletal abnormalities, and male/female infertility. Furthermore, all Brca1 L1363P/L1363P mice exhibited macrocytosis and died due to bone marrow failure or lymphoblastic lymphoma/leukemia with activating Notch1 mutations. These phenotypes closely recapitulate clinical features observed in patients with FA. Collectively, this model effectively demonstrates the significance of the BRCA1-PALB2 interaction in genome integrity and provides an FA model to investigate hematopoietic stem cells for mechanisms underlying progressive failure of hematopoiesis and associated development of leukemia/lymphoma, and other FA phenotypes. SIGNIFICANCE: A new Brca1 mouse model for Fanconi anemia (FA) complementation group S provides a system in which to study phenotypes observed in human FA patients including bone marrow failure.See related commentary by Her and Bunting, p. 4044.
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Affiliation(s)
- Dongju Park
- Department of Cancer Biology and Genetics, The Ohio State University Comprehensive Cancer Center, Columbus, Ohio.
| | - Stephen M Bergin
- The Ohio State University Comprehensive Cancer Center, The James Cancer Hospital and Solove Research Institute, Columbus, Ohio
| | - Dan Jones
- The Ohio State University Comprehensive Cancer Center, The James Cancer Hospital and Solove Research Institute, Columbus, Ohio.,The James Polaris Molecular Laboratory, The James Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio.,Division of Molecular Pathology, Department of Pathology, The Ohio State University, Columbus, Ohio
| | - Peng Ru
- The James Polaris Molecular Laboratory, The James Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio
| | - Christopher S Koivisto
- The Ohio State University Comprehensive Cancer Center, The James Cancer Hospital and Solove Research Institute, Columbus, Ohio
| | - Young-Jun Jeon
- Department of Cancer Biology and Genetics, The Ohio State University Comprehensive Cancer Center, Columbus, Ohio.,Department of Integrative Biotechnology, College of Biotechnology and Bioengineering, Sungkyunkwan University, Suwon, South Korea
| | - Gina M Sizemore
- The Ohio State University Comprehensive Cancer Center, The James Cancer Hospital and Solove Research Institute, Columbus, Ohio.,Department of Radiation Oncology, The Ohio State University, Columbus, Ohio
| | - Raleigh D Kladney
- The Ohio State University Comprehensive Cancer Center, The James Cancer Hospital and Solove Research Institute, Columbus, Ohio
| | - Ashley Hadjis
- Department of Cancer Biology and Genetics, The Ohio State University Comprehensive Cancer Center, Columbus, Ohio
| | - Reena Shakya
- The Ohio State University Comprehensive Cancer Center, The James Cancer Hospital and Solove Research Institute, Columbus, Ohio
| | - Thomas Ludwig
- Department of Cancer Biology and Genetics, The Ohio State University Comprehensive Cancer Center, Columbus, Ohio.
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Trypanosoma brucei RAP1 Has Essential Functional Domains That Are Required for Different Protein Interactions. mSphere 2020; 5:5/1/e00027-20. [PMID: 32102938 PMCID: PMC7045384 DOI: 10.1128/msphere.00027-20] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Trypanosoma brucei causes human African trypanosomiasis and regularly switches its major surface antigen, VSG, to evade the host immune response. VSGs are expressed from subtelomeres in a monoallelic fashion. TbRAP1, a telomere protein, is essential for cell viability and VSG monoallelic expression and suppresses VSG switching. Although TbRAP1 has conserved functional domains in common with its orthologs from yeasts to mammals, the domain functions are unknown. RAP1 orthologs have pleiotropic functions, and interaction with different partners is an important means by which RAP1 executes its different roles. We have established a Cre-loxP-mediated conditional knockout system for TbRAP1 and examined the roles of various functional domains in protein expression, nuclear localization, and protein-protein interactions. This system enables further studies of TbRAP1 point mutation phenotypes. We have also determined functional domains of TbRAP1 that are required for several different protein interactions, shedding light on the underlying mechanisms of TbRAP1-mediated VSG silencing. RAP1 is a telomere protein that is well conserved from protozoa to mammals. It plays important roles in chromosome end protection, telomere length control, and gene expression/silencing at both telomeric and nontelomeric loci. Interaction with different partners is an important mechanism by which RAP1 executes its different functions in yeast. The RAP1 ortholog in Trypanosoma brucei is essential for variant surface glycoprotein (VSG) monoallelic expression, an important aspect of antigenic variation, where T. brucei regularly switches its major surface antigen, VSG, to evade the host immune response. Like other RAP1 orthologs, T. brucei RAP1 (TbRAP1) has conserved functional domains, including BRCA1 C terminus (BRCT), Myb, MybLike, and RAP1 C terminus (RCT). To study functions of various TbRAP1 domains, we established a strain in which one endogenous allele of TbRAP1 is flanked by loxP repeats, enabling its conditional deletion by Cre-mediated recombination. We replaced the other TbRAP1 allele with various mutant alleles lacking individual functional domains and examined their nuclear localization and protein interaction abilities. The N terminus, BRCT, and RCT of TbRAP1 are required for normal protein levels, while the Myb and MybLike domains are essential for normal cell growth. Additionally, the Myb domain of TbRAP1 is required for its interaction with T. brucei TTAGGG repeat-binding factor (TbTRF), while the BRCT domain is required for its self-interaction. Furthermore, the TbRAP1 MybLike domain contains a bipartite nuclear localization signal that is required for its interaction with importin α and its nuclear localization. Interestingly, RAP1’s self-interaction and the interaction between RAP1 and TRF are conserved from kinetoplastids to mammals. However, details of the interaction interfaces have changed throughout evolution. IMPORTANCETrypanosoma brucei causes human African trypanosomiasis and regularly switches its major surface antigen, VSG, to evade the host immune response. VSGs are expressed from subtelomeres in a monoallelic fashion. TbRAP1, a telomere protein, is essential for cell viability and VSG monoallelic expression and suppresses VSG switching. Although TbRAP1 has conserved functional domains in common with its orthologs from yeasts to mammals, the domain functions are unknown. RAP1 orthologs have pleiotropic functions, and interaction with different partners is an important means by which RAP1 executes its different roles. We have established a Cre-loxP-mediated conditional knockout system for TbRAP1 and examined the roles of various functional domains in protein expression, nuclear localization, and protein-protein interactions. This system enables further studies of TbRAP1 point mutation phenotypes. We have also determined functional domains of TbRAP1 that are required for several different protein interactions, shedding light on the underlying mechanisms of TbRAP1-mediated VSG silencing.
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Sun Y, McCorvie TJ, Yates LA, Zhang X. Structural basis of homologous recombination. Cell Mol Life Sci 2020; 77:3-18. [PMID: 31748913 PMCID: PMC6957567 DOI: 10.1007/s00018-019-03365-1] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 10/10/2019] [Accepted: 10/31/2019] [Indexed: 12/12/2022]
Abstract
Homologous recombination (HR) is a pathway to faithfully repair DNA double-strand breaks (DSBs). At the core of this pathway is a DNA recombinase, which, as a nucleoprotein filament on ssDNA, pairs with homologous DNA as a template to repair the damaged site. In eukaryotes Rad51 is the recombinase capable of carrying out essential steps including strand invasion, homology search on the sister chromatid and strand exchange. Importantly, a tightly regulated process involving many protein factors has evolved to ensure proper localisation of this DNA repair machinery and its correct timing within the cell cycle. Dysregulation of any of the proteins involved can result in unchecked DNA damage, leading to uncontrolled cell division and cancer. Indeed, many are tumour suppressors and are key targets in the development of new cancer therapies. Over the past 40 years, our structural and mechanistic understanding of homologous recombination has steadily increased with notable recent advancements due to the advances in single particle cryo electron microscopy. These have resulted in higher resolution structural models of the signalling proteins ATM (ataxia telangiectasia mutated), and ATR (ataxia telangiectasia and Rad3-related protein), along with various structures of Rad51. However, structural information of the other major players involved, such as BRCA1 (breast cancer type 1 susceptibility protein) and BRCA2 (breast cancer type 2 susceptibility protein), has been limited to crystal structures of isolated domains and low-resolution electron microscopy reconstructions of the full-length proteins. Here we summarise the current structural understanding of homologous recombination, focusing on key proteins in recruitment and signalling events as well as the mediators for the Rad51 recombinase.
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Affiliation(s)
- Yueru Sun
- Section of Structural Biology, Department of Infectious Diseases, Imperial College, London, SW7 2AZ, UK
| | - Thomas J McCorvie
- Section of Structural Biology, Department of Infectious Diseases, Imperial College, London, SW7 2AZ, UK
| | - Luke A Yates
- Section of Structural Biology, Department of Infectious Diseases, Imperial College, London, SW7 2AZ, UK
| | - Xiaodong Zhang
- Section of Structural Biology, Department of Infectious Diseases, Imperial College, London, SW7 2AZ, UK.
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Functional Impacts of the BRCA1-mTORC2 Interaction in Breast Cancer. Int J Mol Sci 2019; 20:ijms20235876. [PMID: 31771139 PMCID: PMC6928641 DOI: 10.3390/ijms20235876] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 11/20/2019] [Accepted: 11/21/2019] [Indexed: 12/26/2022] Open
Abstract
Deleterious mutations in Breast Cancer 1 (BRCA1) are associated with an increased risk of breast and ovarian cancer. Mutations in the tandem BRCA1 C-terminal (tBRCT) protein domain disrupt critical protein interactions required for the faithful repair of DNA through homologous recombination, which contributes to oncogenesis. Our studies have identified RICTOR, PRR5, and SIN1 subunits of the mammalian target of rapamycin complex 2 (mTORC2) as interacting partners with the tBRCT domain of BRCA1 leading to the disruption of the mTORC2 complex. However, the interplay between mTORC2 signaling and BRCA1 function in the DNA damage response (DDR) remains to be determined. In this study, we used protein interaction assays to determine the binary interactions between the tBRCT domain and mTORC2 subunits, evaluated the impact of mTOR inhibition on the transcriptional function of the tBRCT, evaluated the impact of mTOR signaling on BRCA1 recruitment to DNA damage-induced foci and determined the breast cancer cell line response to mTOR inhibition dependent upon BRCA1 expression and mutation. This study determined that PRR5, RICTOR, and SIN1 could each independently interact with the BRCA1 tBRCT. Inhibition of mTORC1, but not mTORC1/2, increases BRCA1 transcriptional activation activity. Treatment with pan-mTOR inhibitor PP242 diminishes DNA damage-induced γH2AX and BRCA1 foci formation. Breast cancer cells lacking expression of functional BRCA1 are more sensitive to mTOR inhibitors. These data suggest that mTOR signaling is required for BRCA1 response to DNA damage and breast cancer cells lacking BRCA1 are more sensitive to pan-mTOR inhibition. This work suggests chemotherapeutic strategies using mTOR inhibitors could be tailored for patients that lack functional BRCA1.
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25
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Phospho-peptide binding domains in S. cerevisiae model organism. Biochimie 2019; 163:117-127. [PMID: 31194995 DOI: 10.1016/j.biochi.2019.06.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2019] [Accepted: 06/06/2019] [Indexed: 02/07/2023]
Abstract
Protein phosphorylation is one of the main mechanisms by which signals are transmitted in eukaryotic cells, and it plays a crucial regulatory role in almost all cellular processes. In yeast, more than half of the proteins are phosphorylated in at least one site, and over 20,000 phosphopeptides have been experimentally verified. However, the functional consequences of these phosphorylation events for most of the identified phosphosites are unknown. A family of protein interaction domains selectively recognises phosphorylated motifs to recruit regulatory proteins and activate signalling pathways. Nine classes of dedicated modules are coded by the yeast genome: 14-3-3, FHA, WD40, BRCT, WW, PBD, and SH2. The recognition specificity relies on a few residues on the target protein and has coevolved with kinase specificity. In the present study, we review the current knowledge concerning yeast phospho-binding domains and their networks. We emphasise the relevance of both positive and negative amino acid selection to orchestrate the highly regulated outcomes of inter- and intra-molecular interactions. Finally, we hypothesise that only a small fraction of yeast phosphorylation events leads to the creation of a docking site on the target molecule, while many have a direct effect on the protein or, as has been proposed, have no function at all.
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26
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Chen SH, Yu X. Human DNA ligase IV is able to use NAD+ as an alternative adenylation donor for DNA ends ligation. Nucleic Acids Res 2019; 47:1321-1334. [PMID: 30496552 PMCID: PMC6379666 DOI: 10.1093/nar/gky1202] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 11/09/2018] [Accepted: 11/15/2018] [Indexed: 12/29/2022] Open
Abstract
All the eukaryotic DNA ligases are known to use adenosine triphosphate (ATP) for DNA ligation. Here, we report that human DNA ligase IV, a key enzyme in DNA double-strand break (DSB) repair, is able to use NAD+ as a substrate for double-stranded DNA ligation. In the in vitro ligation assays, we show that the recombinant Ligase IV can use both ATP and NAD+ for DNA ligation. For NAD+-mediated ligation, the BRCA1 C-terminal (BRCT) domain of Ligase IV recognizes NAD+ and facilitates the adenylation of Ligase IV, the first step of ligation. Although XRCC4, the functional partner of Ligase IV, is not required for the NAD+-mediated adenylation, it regulates the transfer of AMP moiety from Ligase IV to the DNA end. Moreover, cancer-associated mutation in the BRCT domain of Ligase IV disrupts the interaction with NAD+, thus abolishes the NAD+-mediated adenylation of Ligase IV and DSB ligation. Disrupting the NAD+ recognition site in the BRCT domain impairs non-homologous end joining (NHEJ) in cell. Taken together, our study reveals that in addition to ATP, Ligase IV may use NAD+ as an alternative adenylation donor for NHEJ repair and maintaining genomic stability.
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Affiliation(s)
- Shih-Hsun Chen
- Department of Cancer Genetics & Epigenetics, Beckman Research Institute, City of Hope, Duarte, CA 91010, USA
| | - Xiaochun Yu
- Department of Cancer Genetics & Epigenetics, Beckman Research Institute, City of Hope, Duarte, CA 91010, USA
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27
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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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28
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Nowsheen S, Aziz K, Luo K, Deng M, Qin B, Yuan J, Jeganathan KB, Yu J, Zhang H, Ding W, van Deursen JM, Lou Z. ZNF506-dependent positive feedback loop regulates H2AX signaling after DNA damage. Nat Commun 2018; 9:2736. [PMID: 30013081 PMCID: PMC6048040 DOI: 10.1038/s41467-018-05161-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 06/12/2018] [Indexed: 11/24/2022] Open
Abstract
Cells respond to cytotoxic DNA double-strand breaks by recruiting repair proteins to the damaged site. Phosphorylation of the histone variant H2AX at S139 and Y142 modulate its interaction with downstream DNA repair proteins and their recruitment to DNA lesions. Here we report ATM-dependent ZNF506 localization to the lesion through MDC1 following DNA damage. ZNF506, in turn, recruits the protein phosphatase EYA, resulting in dephosphorylation of H2AX at Y142, which further facilitates the recruitment of MDC1 and other downstream repair factors. Thus, ZNF506 regulates the early dynamic signaling in the DNA damage response (DDR) pathway and controls progressive downstream signal amplification. Cells lacking ZNF506 or harboring mutations found in cancer patient samples are more sensitive to radiation, offering a potential new therapeutic option for cancers with mutations in this pathway. Taken together, these results demonstrate how the DDR pathway is orchestrated by ZNF506 to maintain genomic integrity. Following double-strand break a cascade of events leads to the recruitment of repair factors to damaged sites. Here the authors identify ZNF506 as a key factor that mediates post-translational modification changes in H2AX affecting the DNA damage response.
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Affiliation(s)
- Somaira Nowsheen
- Mayo Clinic Medical Scientist Training Program, Mayo Clinic School of Medicine and Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN, 55905, USA.,Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, 55905, USA
| | - Khaled Aziz
- Mayo Clinic Medical Scientist Training Program, Mayo Clinic School of Medicine and Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN, 55905, USA
| | - Kuntian Luo
- Department of Oncology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Min Deng
- Department of Oncology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Bo Qin
- Department of Oncology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Jian Yuan
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, 55905, USA.,Research Center for Translational Medicine, Key Laboratory of Arrhythmias of the Ministry of Education of China, East Hospital, Tongji University School of Medicine, Shanghai, 200120, China
| | - Karthik B Jeganathan
- Department of Pediatrics and Adolescent Medicine, Mayo Clinic, Rochester, MN, 55905, USA
| | - Jia Yu
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, 55905, USA
| | - Henan Zhang
- Department of Hematology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Wei Ding
- Department of Hematology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Jan M van Deursen
- Department of Pediatrics and Adolescent Medicine, Mayo Clinic, Rochester, MN, 55905, USA
| | - Zhenkun Lou
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, 55905, USA. .,Department of Oncology, Mayo Clinic, Rochester, MN, 55905, USA.
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29
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Kim S, Jin H, Seo HR, Lee HJ, Lee YS. Regulating BRCA1 protein stability by cathepsin S-mediated ubiquitin degradation. Cell Death Differ 2018; 26:812-825. [PMID: 30006610 PMCID: PMC6461859 DOI: 10.1038/s41418-018-0153-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 05/25/2018] [Accepted: 06/08/2018] [Indexed: 01/21/2023] Open
Abstract
Cathepsin S (CTSS) is a cysteine protease that is thought to play a role in many physiological and pathological processes including tumor growth, angiogenesis, and metastasis; it has been identified as a radiation response gene. Here, we examined the role of CTSS in regulating the DNA damage response in breast cancer cells. Activating CTSS (producing the cleavage form of the protein) by radiation induced proteolytic degradation of BRCA1, which ultimately suppressed DNA double-strand break repair activity. Depletion of CTSS by RNAi or expression of a mutant type of CTSS enhanced the protein stability of BRCA1 by inhibiting its ubiquitination. CTSS interacted with the BRCT domain of BRCA1 and facilitated ubiquitin-mediated proteolytic degradation of BRCA1, which was tightly associated with decreased BRCA1-mediated DNA repair activity. Treatment with a pharmacological CTSS inhibitor inhibited proteolytic degradation of BRCA1 and restored BRCA1 function. Depletion of CTSS by shRNA delayed tumor growth in a xenograft mouse model, only in the presence of functional BRCA1. Spontaneously uced rat mammary tumors and human breast cancer tissues with high levels of CTSS expression showed low BRCA1 expression. From these data, we suggest that CTSS inhibition is a good strategy for functional restoration of BRCA1 in breast cancers with reduced BRCA1 protein stability.
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Affiliation(s)
- SeoYoung Kim
- Graduate School of Pharmaceutical Sciences, Ewha Womans University, Seoul, 120-750, Korea
| | - Hee Jin
- Graduate School of Pharmaceutical Sciences, Ewha Womans University, Seoul, 120-750, Korea
| | - Hang-Rhan Seo
- Functional Morphometry II, Institute Pasteur Korea, Bundang-gu, Seongnam-si, Gyeonggi-do, 463-400, Korea
| | - Hae June Lee
- Division of Basic Radiation Bioscience, Korea Institute of Radiological and Medical Sciences, Seoul, 139-706, Korea
| | - Yun-Sil Lee
- Graduate School of Pharmaceutical Sciences, Ewha Womans University, Seoul, 120-750, Korea.
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30
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Cusin I, Teixeira D, Zahn-Zabal M, Rech de Laval V, Gleizes A, Viassolo V, Chappuis PO, Hutter P, Bairoch A, Gaudet P. A new bioinformatics tool to help assess the significance of BRCA1 variants. Hum Genomics 2018; 12:36. [PMID: 29996917 PMCID: PMC6042458 DOI: 10.1186/s40246-018-0168-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Accepted: 06/25/2018] [Indexed: 12/23/2022] Open
Abstract
Background Germline pathogenic variants in the breast cancer type 1 susceptibility gene BRCA1 are associated with a 60% lifetime risk for breast and ovarian cancer. This overall risk estimate is for all BRCA1 variants; obviously, not all variants confer the same risk of developing a disease. In cancer patients, loss of BRCA1 function in tumor tissue has been associated with an increased sensitivity to platinum agents and to poly-(ADP-ribose) polymerase (PARP) inhibitors. For clinical management of both at-risk individuals and cancer patients, it would be important that each identified genetic variant be associated with clinical significance. Unfortunately for the vast majority of variants, the clinical impact is unknown. The availability of results from studies assessing the impact of variants on protein function may provide insight of crucial importance. Results and conclusion We have collected, curated, and structured the molecular and cellular phenotypic impact of 3654 distinct BRCA1 variants. The data was modeled in triple format, using the variant as a subject, the studied function as the object, and a predicate describing the relation between the two. Each annotation is supported by a fully traceable evidence. The data was captured using standard ontologies to ensure consistency, and enhance searchability and interoperability. We have assessed the extent to which functional defects at the molecular and cellular levels correlate with the clinical interpretation of variants by ClinVar submitters. Approximately 30% of the ClinVar BRCA1 missense variants have some molecular or cellular assay available in the literature. Pathogenic variants (as assigned by ClinVar) have at least some significant functional defect in 94% of testable cases. For benign variants, 77% of ClinVar benign variants, for which neXtProt Cancer variant portal has data, shows either no or mild experimental functional defects. While this does not provide evidence for clinical interpretation of variants, it may provide some guidance for variants of unknown significance, in the absence of more reliable data. The neXtProt Cancer variant portal (https://www.nextprot.org/portals/breast-cancer) contains over 6300 observations at the molecular and/or cellular level for BRCA1 variants.
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Affiliation(s)
- Isabelle Cusin
- CALIPHO group, SIB Swiss Institute of Bioinformatics, 1211, Geneva 4, Switzerland
| | - Daniel Teixeira
- CALIPHO group, SIB Swiss Institute of Bioinformatics, 1211, Geneva 4, Switzerland
| | - Monique Zahn-Zabal
- CALIPHO group, SIB Swiss Institute of Bioinformatics, 1211, Geneva 4, Switzerland
| | - Valentine Rech de Laval
- CALIPHO group, SIB Swiss Institute of Bioinformatics, 1211, Geneva 4, Switzerland.,Department of Human Protein Sciences, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Anne Gleizes
- CALIPHO group, SIB Swiss Institute of Bioinformatics, 1211, Geneva 4, Switzerland
| | - Valeria Viassolo
- Oncogenetics and Cancer Prevention Unit, Division of Oncology, University Hospitals of Geneva, 1205, Geneva, Switzerland
| | - Pierre O Chappuis
- Oncogenetics and Cancer Prevention Unit, Division of Oncology, University Hospitals of Geneva, 1205, Geneva, Switzerland.,Division of Genetic Medicine, University Hospitals of Geneva, 1205, Geneva, Switzerland
| | - Pierre Hutter
- Sophia Genetics, Rue du Centre 172, 1025, Saint Sulpice, Switzerland
| | - Amos Bairoch
- CALIPHO group, SIB Swiss Institute of Bioinformatics, 1211, Geneva 4, Switzerland.,Department of Human Protein Sciences, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Pascale Gaudet
- CALIPHO group, SIB Swiss Institute of Bioinformatics, 1211, Geneva 4, Switzerland. .,Department of Human Protein Sciences, Faculty of Medicine, University of Geneva, Geneva, Switzerland.
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31
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Periasamy J, Kurdekar V, Jasti S, Nijaguna MB, Boggaram S, Hurakadli MA, Raina D, Kurup LM, Chintha C, Manjunath K, Goyal A, Sadasivam G, Bharatham K, Padigaru M, Potluri V, Venkitaraman AR. Targeting Phosphopeptide Recognition by the Human BRCA1 Tandem BRCT Domain to Interrupt BRCA1-Dependent Signaling. Cell Chem Biol 2018; 25:677-690.e12. [PMID: 29606576 PMCID: PMC6015222 DOI: 10.1016/j.chembiol.2018.02.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 11/24/2017] [Accepted: 02/22/2018] [Indexed: 02/06/2023]
Abstract
Intracellular signals triggered by DNA breakage flow through proteins containing BRCT (BRCA1 C-terminal) domains. This family, comprising 23 conserved phosphopeptide-binding modules in man, is inaccessible to small-molecule chemical inhibitors. Here, we develop Bractoppin, a drug-like inhibitor of phosphopeptide recognition by the human BRCA1 tandem (t)BRCT domain, which selectively inhibits substrate binding with nanomolar potency in vitro. Structure-activity exploration suggests that Bractoppin engages BRCA1 tBRCT residues recognizing pSer in the consensus motif, pSer-Pro-Thr-Phe, plus an abutting hydrophobic pocket that is distinct in structurally related BRCT domains, conferring selectivity. In cells, Bractoppin inhibits substrate recognition detected by Förster resonance energy transfer, and diminishes BRCA1 recruitment to DNA breaks, in turn suppressing damage-induced G2 arrest and assembly of the recombinase, RAD51. But damage-induced MDC1 recruitment, single-stranded DNA (ssDNA) generation, and TOPBP1 recruitment remain unaffected. Thus, an inhibitor of phosphopeptide recognition selectively interrupts BRCA1 tBRCT-dependent signals evoked by DNA damage. Bractoppin selectively blocks phosphopeptide recognition by the BRCA1 tBRCT domain Bractoppin engages tBRCT residues recognizing pSer, plus an adjacent pocket Bractoppin interrupts BRCA1 tBRCT-dependent cellular signals evoked by DNA damage This work opens avenues to inhibit intracellular signaling by the tBRCT domain family
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Affiliation(s)
- Jayaprakash Periasamy
- Center for Chemical Biology & Therapeutics, InSTEM, Bellary Road, Bangalore, Karnataka 560065, India
| | - Vadiraj Kurdekar
- Center for Chemical Biology & Therapeutics, InSTEM, Bellary Road, Bangalore, Karnataka 560065, India
| | - Subbarao Jasti
- Center for Chemical Biology & Therapeutics, InSTEM, Bellary Road, Bangalore, Karnataka 560065, India
| | - Mamatha B Nijaguna
- Center for Chemical Biology & Therapeutics, InSTEM, Bellary Road, Bangalore, Karnataka 560065, India
| | - Sanjana Boggaram
- Center for Chemical Biology & Therapeutics, InSTEM, Bellary Road, Bangalore, Karnataka 560065, India
| | - Manjunath A Hurakadli
- Center for Chemical Biology & Therapeutics, InSTEM, Bellary Road, Bangalore, Karnataka 560065, India
| | - Dhruv Raina
- Center for Chemical Biology & Therapeutics, InSTEM, Bellary Road, Bangalore, Karnataka 560065, India
| | - Lokavya Meenakshi Kurup
- Center for Chemical Biology & Therapeutics, InSTEM, Bellary Road, Bangalore, Karnataka 560065, India
| | - Chetan Chintha
- Center for Chemical Biology & Therapeutics, InSTEM, Bellary Road, Bangalore, Karnataka 560065, India
| | - Kavyashree Manjunath
- Center for Chemical Biology & Therapeutics, InSTEM, Bellary Road, Bangalore, Karnataka 560065, India
| | - Aneesh Goyal
- Center for Chemical Biology & Therapeutics, InSTEM, Bellary Road, Bangalore, Karnataka 560065, India
| | - Gayathri Sadasivam
- Center for Chemical Biology & Therapeutics, InSTEM, Bellary Road, Bangalore, Karnataka 560065, India
| | - Kavitha Bharatham
- Center for Chemical Biology & Therapeutics, InSTEM, Bellary Road, Bangalore, Karnataka 560065, India
| | - Muralidhara Padigaru
- Center for Chemical Biology & Therapeutics, InSTEM, Bellary Road, Bangalore, Karnataka 560065, India
| | - Vijay Potluri
- Center for Chemical Biology & Therapeutics, InSTEM, Bellary Road, Bangalore, Karnataka 560065, India
| | - Ashok R Venkitaraman
- Center for Chemical Biology & Therapeutics, InSTEM, Bellary Road, Bangalore, Karnataka 560065, India; Medical Research Council Cancer Unit, University of Cambridge, Hills Road, Cambridge CB2 0XZ, UK.
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32
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Nowsheen S, Aziz K, Aziz A, Deng M, Qin B, Luo K, Jeganathan KB, Zhang H, Liu T, Yu J, Deng Y, Yuan J, Ding W, van Deursen JM, Lou Z. L3MBTL2 orchestrates ubiquitin signalling by dictating the sequential recruitment of RNF8 and RNF168 after DNA damage. Nat Cell Biol 2018; 20:455-464. [PMID: 29581593 PMCID: PMC6083879 DOI: 10.1038/s41556-018-0071-x] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 02/22/2018] [Indexed: 12/12/2022]
Abstract
Cells respond to cytotoxic DNA double-strand breaks (DSBs) by recruiting DNA repair proteins to the damaged site. This recruitment is dependent on ubiquitylation of adjacent chromatin areas by E3 ubiquitin ligases such as RNF8 and RNF168, which are recruited sequentially to the DSBs. However, it is unclear what dictates the sequential order and recruits RNF168 to the DNA lesion. Here, we reveal that L3MBTL2 (lethal(3)malignant brain tumour-like protein 2) is the missing link between RNF8 and RNF168. We found that L3MBTL2 is recruited by MDC1 and subsequently ubiquitylated by RNF8. Ubiquitylated L3MBTL2, in turn, facilitates recruitment of RNF168 to the DNA lesion and promotes DNA DSB repair. These results identify L3MBTL2 as a key target of RNF8 following DNA damage and demonstrates how the DNA damage response pathway is orchestrated by ubiquitin signalling.
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Affiliation(s)
- Somaira Nowsheen
- Mayo Medical Scientist Training Program, Mayo Clinic School of Medicine and Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN, USA
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, USA
| | - Khaled Aziz
- Mayo Medical Scientist Training Program, Mayo Clinic School of Medicine and Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN, USA
| | - Asef Aziz
- Department of Pediatrics and Adolescent Medicine, Mayo Clinic, Rochester, MN, USA
| | - Min Deng
- Department of Oncology, Mayo Clinic, Rochester, MN, USA
| | - Bo Qin
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, USA
- Department of Oncology, Mayo Clinic, Rochester, MN, USA
| | - Kuntian Luo
- Department of Oncology, Mayo Clinic, Rochester, MN, USA
| | - Karthik B Jeganathan
- Department of Pediatrics and Adolescent Medicine, Mayo Clinic, Rochester, MN, USA
| | - Henan Zhang
- Department of Hematology, Mayo Clinic, Rochester, MN, USA
| | - Tongzheng Liu
- Department of Oncology, Mayo Clinic, Rochester, MN, USA
- Institute of Tumor Pharmacology, Jinan University, Guangzhou, China
| | - Jia Yu
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, USA
| | - Yibin Deng
- Laboratory of Cancer Genetics, The University of Minnesota Hormel Institute, Austin, MN, USA
| | - Jian Yuan
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, USA
- Research Center for Translational Medicine, East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Wei Ding
- Department of Hematology, Mayo Clinic, Rochester, MN, USA
| | - Jan M van Deursen
- Department of Pediatrics and Adolescent Medicine, Mayo Clinic, Rochester, MN, USA
| | - Zhenkun Lou
- Department of Oncology, Mayo Clinic, Rochester, MN, USA.
- Research Center for Translational Medicine, East Hospital, Tongji University School of Medicine, Shanghai, China.
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33
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Hou WH, Chen SH, Yu X. Poly-ADP ribosylation in DNA damage response and cancer therapy. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2017; 780:82-91. [PMID: 31395352 DOI: 10.1016/j.mrrev.2017.09.004] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 09/06/2017] [Accepted: 09/18/2017] [Indexed: 12/12/2022]
Abstract
Poly(ADP-ribosyl)ation (aka PARylation) is a unique protein post-translational modification (PTM) first described over 50 years ago. PARylation regulates a number of biological processes including chromatin remodeling, the DNA damage response (DDR), transcription, apoptosis, and mitosis. The subsequent discovery of poly(ADP-ribose) polymerase-1 (PARP-1) catalyzing DNA-dependent PARylation spearheaded the field of DDR. The expanding knowledge about the poly ADP-ribose (PAR) recognition domains prompted the discovery of novel DDR factors and revealed crosstalk with other protein PTMs including phosphorylation, ubiquitination, methylation and acetylation. In this review, we highlight the current knowledge on PAR-regulated DDR, PAR recognition domain, and PARP inhibition in cancer therapy.
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Affiliation(s)
- Wei-Hsien Hou
- Department of Radiation Oncology, City of Hope National Medical Center, Duarte, California, USA
| | - Shih-Hsun Chen
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute, City of Hope National Medical Center, Duarte, California, USA
| | - Xiaochun Yu
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute, City of Hope National Medical Center, Duarte, California, USA.
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34
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Takaoka M, Miki Y. BRCA1 gene: function and deficiency. Int J Clin Oncol 2017; 23:36-44. [PMID: 28884397 DOI: 10.1007/s10147-017-1182-2] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 08/17/2017] [Indexed: 10/18/2022]
Abstract
The BRCA1 protein, a hereditary breast and ovarian cancer-causing gene product, is known as a multifunctional protein that performs various functions in cells. It is well known, along with BRCA 2, to cause hereditary breast and ovarian cancer, but here we will specifically focus on BRCA1. We introduce the mechanism and the latest report on homologous recombination repair, replication, involvement in checkpoint regulation, transcription, chromatin remodeling, and cytoplasmic function (centrosome regulation, apoptosis, selective autophagy), and consider the possibility of carcinogenesis from inhibition of the intracellular functions in each. We also consider the possibility of drug development based on each function. Finally, we will explain, from data obtained through basic research, that an appropriate regimen is important for raising the response rate for poly (ADP)-ribose polymerase inhibitors, in the case of low susceptibility, iatrogenic toxicity, tolerance, etc.
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Affiliation(s)
- Miho Takaoka
- Department of Molecular Genetics, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan
| | - Yoshio Miki
- Department of Molecular Genetics, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan. .,Department of Genetic Diagnosis, The Cancer Institute, Japanese Foundation for Cancer Research, 3-10-6 Ariake, Koto-ku, Tokyo, 135-8550, Japan.
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35
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Chen Y, Liu H, Zhang H, Sun C, Hu Z, Tian Q, Peng C, Jiang P, Hua H, Li X, Pei H. And-1 coordinates with CtIP for efficient homologous recombination and DNA damage checkpoint maintenance. Nucleic Acids Res 2017; 45:2516-2530. [PMID: 27940552 PMCID: PMC5389581 DOI: 10.1093/nar/gkw1212] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 11/25/2016] [Indexed: 12/29/2022] Open
Abstract
To prevent genomic instability, cells respond to DNA lesions by blocking cell cycle progression and initiating DNA repair. Homologous recombination repair of DNA breaks requires CtIP-dependent resection of the DNA ends, which is thought to play a key role in activation of CHK1 kinase to induce the cell cycle checkpoint. But the mechanism is still not fully understood. Here, we establish that And-1, a replisome component, promotes DNA-end resection and DNA repair by homologous recombination. Mechanistically, And-1 interacts with CtIP and regulates CtIP recruitment to DNA damage sites. And-1 localizes to sites of DNA damage dependent on MDC1-RNF8 pathway, and is required for resistance to many DNA-damaging and replication stress-inducing agents. Furthermore, we show that And-1-CtIP axis is critically required for sustained ATR-CHK1 checkpoint signaling and for maintaining both the intra-S- and G2-phase checkpoints. Our findings thus identify And-1 as a novel DNA repair regulator and reveal how the replisome regulates the DNA damage induced checkpoint and genomic stability.
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Affiliation(s)
- Yali Chen
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, Beijing Institute of Radiation Medicine, Beijing 100850, China
| | - Hailong Liu
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, Beijing Institute of Radiation Medicine, Beijing 100850, China
| | - Haoxing Zhang
- School of Life Sciences and Oceanography, Shenzhen University, Shenzhen, Guangdong Province 518060, China
| | - Changqing Sun
- Department of neurosurgery, Tianjin Baodi Hospital, Baodi Clinical College of Tianjin Medical University, Tianjin 301800, China
| | - Zhaohua Hu
- Department of Orthopedics, Renhe Hospital of Three Gorges University, Yichang 443001, China
| | - Qingsong Tian
- Department of Orthopedics, Renhe Hospital of Three Gorges University, Yichang 443001, China
| | - Changmin Peng
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Industrial Microbiology Key Lab, College of Biotechnology, Tianjin University of Science and Technology, No 29, 13ST. TEDA, Tianjin 300457, China
| | - Pei Jiang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, Beijing Institute of Radiation Medicine, Beijing 100850, China
| | - Hui Hua
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, Beijing Institute of Radiation Medicine, Beijing 100850, China
| | - Xinzhi Li
- Department of Orthopedics, Renhe Hospital of Three Gorges University, Yichang 443001, China
| | - Huadong Pei
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, Beijing Institute of Radiation Medicine, Beijing 100850, China
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Ma J, Dai Q, Li X, Zhu X, Ma T, Qiao X, Shen S, Liu X. Dipentaerythritol penta-/hexa-acrylate based-highly cross-linked hybrid monolithic column: Preparation and its applications for ultrahigh efficiency separation of proteins. Anal Chim Acta 2017; 963:143-152. [DOI: 10.1016/j.aca.2017.01.057] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 01/21/2017] [Accepted: 01/23/2017] [Indexed: 12/16/2022]
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Liu Y, Cussiol JR, Dibitetto D, Sims JR, Twayana S, Weiss RS, Freire R, Marini F, Pellicioli A, Smolka MB. TOPBP1 Dpb11 plays a conserved role in homologous recombination DNA repair through the coordinated recruitment of 53BP1 Rad9. J Cell Biol 2017; 216:623-639. [PMID: 28228534 PMCID: PMC5350513 DOI: 10.1083/jcb.201607031] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 11/30/2016] [Accepted: 01/09/2017] [Indexed: 01/24/2023] Open
Abstract
The scaffold protein TOPBP1Dpb11 has been implicated in homologous recombination DNA repair, but its function and mechanism of action remain unclear. Liu et al. define a conserved role for TOPBP1Dpb11 in recombination control through regulated, opposing interactions with pro- and anti-resection factors. Genome maintenance and cancer suppression require homologous recombination (HR) DNA repair. In yeast and mammals, the scaffold protein TOPBP1Dpb11 has been implicated in HR, although its precise function and mechanism of action remain elusive. In this study, we show that yeast Dpb11 plays an antagonistic role in recombination control through regulated protein interactions. Dpb11 mediates opposing roles in DNA end resection by coordinating both the stabilization and exclusion of Rad9 from DNA lesions. The Mec1 kinase promotes the pro-resection function of Dpb11 by mediating its interaction with the Slx4 scaffold. Human TOPBP1Dpb11 engages in interactions with the anti-resection factor 53BP1 and the pro-resection factor BRCA1, suggesting that TOPBP1 also mediates opposing functions in HR control. Hyperstabilization of the 53BP1–TOPBP1 interaction enhances the recruitment of 53BP1 to nuclear foci in the S phase, resulting in impaired HR and the accumulation of chromosomal aberrations. Our results support a model in which TOPBP1Dpb11 plays a conserved role in mediating a phosphoregulated circuitry for the control of recombinational DNA repair.
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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
| | - José Renato Cussiol
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853
| | - Diego Dibitetto
- Department of Biosciences, University of Milan, 20133 Milan, Italy
| | - Jennie Rae Sims
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853
| | - Shyam Twayana
- Department of Biosciences, University of Milan, 20133 Milan, Italy
| | | | - Raimundo Freire
- Unidad de Investigación, Hospital Universitario de Canarias, Instituto de Tecnologias Biomedicas, 38320 Tenerife, Spain
| | - Federica Marini
- Department of Biosciences, University of Milan, 20133 Milan, Italy
| | | | - Marcus Bustamante Smolka
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853
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Liang S, Esswein SR, Ochi T, Wu Q, Ascher DB, Chirgadze D, Sibanda BL, Blundell TL. Achieving selectivity in space and time with DNA double-strand-break response and repair: molecular stages and scaffolds come with strings attached. Struct Chem 2016. [DOI: 10.1007/s11224-016-0841-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Her J, Soo Lee N, Kim Y, Kim H. Factors forming the BRCA1-A complex orchestrate BRCA1 recruitment to the sites of DNA damage. Acta Biochim Biophys Sin (Shanghai) 2016; 48:658-64. [PMID: 27325824 DOI: 10.1093/abbs/gmw047] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2016] [Accepted: 04/18/2016] [Indexed: 12/28/2022] Open
Abstract
Sustaining genomic integrity is essential for preventing onset of cancers. Therefore, human cells evolve to have refined biological pathways to defend genetic materials from various genomic insults. DNA damage response and DNA repair pathways essential for genome maintenance are accomplished by cooperative executions of multiple factors including breast cancer type 1 susceptibility protein (BRCA1). BRCA1 is initially identified as an altered gene in the hereditary breast cancer patients. Since then, tremendous efforts to understand the functions of BRAC1 reveal that BRCA1 is found in distinct complexes, including BRCA1-A, BRCA1-B, BRCA1-C, and the BRCA1/PALB2/BRCA2 complex, and plays diverse roles in a context-dependent manner. Among the complexes, BRCA1-A is critical for BRCA1 recruitment to the sites of DNA damage. Factors comprising the BRCA1-A include RAP80, CCDC98/Abraxas, BRCC36, BRCC45, BARD1, BRCA1, and MERIT40, a RAP80-associated factor. In this review, we summarize recent findings of the factors that form the BRCA1-A complex.
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Affiliation(s)
- Joonyoung Her
- Department of Biological Sciences, Sookmyung Women's University, Seoul 04310, Republic of Korea
| | - Nam Soo Lee
- Department of Biological Sciences, Sungkyunkwan University, Suwon 440-746, Republic of Korea
| | - Yonghwan Kim
- Department of Biological Sciences, Sookmyung Women's University, Seoul 04310, Republic of Korea
| | - Hongtae Kim
- Department of Biological Sciences, Sungkyunkwan University, Suwon 440-746, Republic of Korea Center for Neuroscience Imaging Research, Institute for Basic Science (IBS), Sungkyunkwan University, Suwon 440-746, Republic of Korea
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40
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Jhuraney A, Woods NT, Wright G, Rix L, Kinose F, Kroeger JL, Remily-Wood E, Cress WD, Koomen JM, Brantley SG, Gray JE, Haura EB, Rix U, Monteiro AN. PAXIP1 Potentiates the Combination of WEE1 Inhibitor AZD1775 and Platinum Agents in Lung Cancer. Mol Cancer Ther 2016; 15:1669-81. [PMID: 27196765 PMCID: PMC4936941 DOI: 10.1158/1535-7163.mct-15-0182] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2015] [Accepted: 04/09/2016] [Indexed: 11/16/2022]
Abstract
The DNA damage response (DDR) involves a complex network of signaling events mediated by modular protein domains such as the BRCA1 C-terminal (BRCT) domain. Thus, proteins that interact with BRCT domains and are a part of the DDR constitute potential targets for sensitization to DNA-damaging chemotherapy agents. We performed a pharmacologic screen to evaluate 17 kinases, identified in a BRCT-mediated interaction network as targets to enhance platinum-based chemotherapy in lung cancer. Inhibition of mitotic kinase WEE1 was found to have the most effective response in combination with platinum compounds in lung cancer cell lines. In the BRCT-mediated interaction network, WEE1 was found in complex with PAXIP1, a protein containing six BRCT domains involved in transcription and in the cellular response to DNA damage. We show that PAXIP1 BRCT domains regulate WEE1-mediated phosphorylation of CDK1. Furthermore, ectopic expression of PAXIP1 promotes enhanced caspase-3-mediated apoptosis in cells treated with WEE1 inhibitor AZD1775 (formerly, MK-1775) and cisplatin compared with cells treated with AZD1775 alone. Cell lines and patient-derived xenograft models expressing both PAXIP1 and WEE1 exhibited synergistic effects of AZD1775 and cisplatin. In summary, PAXIP1 is involved in sensitizing lung cancer cells to the WEE1 inhibitor AZD1775 in combination with platinum-based treatment. We propose that WEE1 and PAXIP1 levels may be used as mechanism-based biomarkers of response when WEE1 inhibitor AZD1775 is combined with DNA-damaging agents. Mol Cancer Ther; 15(7); 1669-81. ©2016 AACR.
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Affiliation(s)
- Ankita Jhuraney
- Department of Cancer Epidemiology, H. Lee Moffitt Cancer Center & Research Institute, Tampa, Florida. Cancer Biology PhD Program, University of South Florida, Tampa, Florida
| | - Nicholas T Woods
- Department of Cancer Epidemiology, H. Lee Moffitt Cancer Center & Research Institute, Tampa, Florida
| | - Gabriela Wright
- Department of Drug Discovery, H. Lee Moffitt Cancer Center & Research Institute, Tampa, Florida
| | - Lily Rix
- Department of Drug Discovery, H. Lee Moffitt Cancer Center & Research Institute, Tampa, Florida
| | - Fumi Kinose
- Department of Thoracic Oncology, H. Lee Moffitt Cancer Center & Research Institute, Tampa, Florida
| | - Jodi L Kroeger
- Flow Cytometry Core, H. Lee Moffitt Cancer Center & Research Institute, Tampa, Florida
| | - Elizabeth Remily-Wood
- Molecular Oncology Program, H. Lee Moffitt Cancer Center & Research Institute, Tampa, Florida
| | - W Douglas Cress
- Molecular Oncology Program, H. Lee Moffitt Cancer Center & Research Institute, Tampa, Florida
| | - John M Koomen
- Molecular Oncology Program, H. Lee Moffitt Cancer Center & Research Institute, Tampa, Florida
| | - Stephen G Brantley
- M2Gen, H. Lee Moffitt Cancer Center & Research Institute, Tampa, Florida
| | - Jhanelle E Gray
- Department of Thoracic Oncology, H. Lee Moffitt Cancer Center & Research Institute, Tampa, Florida
| | - Eric B Haura
- Department of Thoracic Oncology, H. Lee Moffitt Cancer Center & Research Institute, Tampa, Florida
| | - Uwe Rix
- Department of Drug Discovery, H. Lee Moffitt Cancer Center & Research Institute, Tampa, Florida.
| | - Alvaro N Monteiro
- Department of Cancer Epidemiology, H. Lee Moffitt Cancer Center & Research Institute, Tampa, Florida.
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Abstract
Recent advances in the development of functional materials offer new tools to dissect human health and disease mechanisms. The use of tunable surfaces is especially appealing as substrates can be tailored to fit applications involving specific cell types or tissues. Here we use tunable materials to facilitate the three-dimensional (3D) analysis of BRCA1 gene regulatory complexes derived from human cancer cells. We employed a recently developed microchip platform to isolate BRCA1 protein assemblies natively formed in breast cancer cells with and without BRCA1 mutations. The captured assemblies proved amenable to cryo-electron microscopy (EM) imaging and downstream computational analysis. Resulting 3D structures reveal the manner in which wild-type BRCA1 engages the RNA polymerase II (RNAP II) core complex that contained K63-linked ubiquitin moieties—a putative signal for DNA repair. Importantly, we also determined that molecular assemblies harboring the BRCA15382insC mutation exhibited altered protein interactions and ubiquitination patterns compared to wild-type complexes. Overall, our analyses proved optimal for developing new structural oncology applications involving patient-derived cancer cells, while expanding our knowledge of BRCA1’s role in gene regulatory events.
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42
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New concepts on BARD1: Regulator of BRCA pathways and beyond. Int J Biochem Cell Biol 2016; 72:1-17. [DOI: 10.1016/j.biocel.2015.12.008] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 12/15/2015] [Accepted: 12/16/2015] [Indexed: 01/09/2023]
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Wu Q, Paul A, Su D, Mehmood S, Foo TK, Ochi T, Bunting EL, Xia B, Robinson CV, Wang B, Blundell TL. Structure of BRCA1-BRCT/Abraxas Complex Reveals Phosphorylation-Dependent BRCT Dimerization at DNA Damage Sites. Mol Cell 2016; 61:434-448. [PMID: 26778126 PMCID: PMC4747905 DOI: 10.1016/j.molcel.2015.12.017] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 10/22/2015] [Accepted: 12/09/2015] [Indexed: 01/22/2023]
Abstract
BRCA1 accumulation at DNA damage sites is an important step for its function in the DNA damage response and in DNA repair. BRCA1-BRCT domains bind to proteins containing the phosphorylated serine-proline-x-phenylalanine (pSPxF) motif including Abraxas, Bach1/FancJ, and CtIP. In this study, we demonstrate that ionizing radiation (IR)-induces ATM-dependent phosphorylation of serine 404 (S404) next to the pSPxF motif. Crystal structures of BRCT/Abraxas show that phosphorylation of S404 is important for extensive interactions through the N-terminal sequence outside the pSPxF motif and leads to formation of a stable dimer. Mutation of S404 leads to deficiency in BRCA1 accumulation at DNA damage sites and cellular sensitivity to IR. In addition, two germline mutations of BRCA1 are found to disrupt the dimer interface and dimer formation. Thus, we demonstrate a mechanism involving IR-induced phosphorylation and dimerization of the BRCT/Abraxas complex for regulating Abraxas-mediated recruitment of BRCA1 in response to IR.
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Affiliation(s)
- Qian Wu
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, CB2 1GA Cambridge, UK
| | - Atanu Paul
- Department of Genetics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA; Genes and Development Program, The University of Texas Graduate School of Biomedical Sciences at Houston, 6767 Bertner Avenue, Houston, TX 77030, USA
| | - Dan Su
- Department of Genetics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA
| | - Shahid Mehmood
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, OX1 3QZ Oxford, UK
| | - Tzeh Keong Foo
- Department of Radiation Oncology, Robert Wood Johnson Medical School, Rutgers Cancer Institute of New Jersey, 195 Little Albany Street, New Brunswick, NJ 08903, USA
| | - Takashi Ochi
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, CB2 1GA Cambridge, UK
| | - Emma L Bunting
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, CB2 1GA Cambridge, UK
| | - Bing Xia
- Department of Radiation Oncology, Robert Wood Johnson Medical School, Rutgers Cancer Institute of New Jersey, 195 Little Albany Street, New Brunswick, NJ 08903, USA
| | - Carol V Robinson
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, OX1 3QZ Oxford, UK
| | - Bin Wang
- Department of Genetics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA; Genes and Development Program, The University of Texas Graduate School of Biomedical Sciences at Houston, 6767 Bertner Avenue, Houston, TX 77030, USA.
| | - Tom L Blundell
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, CB2 1GA Cambridge, UK.
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44
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Baldock RA, Day M, Wilkinson OJ, Cloney R, Jeggo PA, Oliver AW, Watts FZ, Pearl LH. ATM Localization and Heterochromatin Repair Depend on Direct Interaction of the 53BP1-BRCT2 Domain with γH2AX. Cell Rep 2015; 13:2081-9. [PMID: 26628370 PMCID: PMC4688034 DOI: 10.1016/j.celrep.2015.10.074] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 09/28/2015] [Accepted: 10/26/2015] [Indexed: 01/02/2023] Open
Abstract
53BP1 plays multiple roles in mammalian DNA damage repair, mediating pathway choice and facilitating DNA double-strand break repair in heterochromatin. Although it possesses a C-terminal BRCT2 domain, commonly involved in phospho-peptide binding in other proteins, initial recruitment of 53BP1 to sites of DNA damage depends on interaction with histone post-translational modifications--H4K20me2 and H2AK13/K15ub--downstream of the early γH2AX phosphorylation mark of DNA damage. We now show that, contrary to current models, the 53BP1-BRCT2 domain binds γH2AX directly, providing a third post-translational mark regulating 53BP1 function. We find that the interaction of 53BP1 with γH2AX is required for sustaining the 53BP1-dependent focal concentration of activated ATM that facilitates repair of DNA double-strand breaks in heterochromatin in G1.
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Affiliation(s)
- Robert A Baldock
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK
| | - 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
| | - Oliver J Wilkinson
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK
| | - Ross Cloney
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK
| | - Penelope A Jeggo
- 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
| | - Felicity Z Watts
- 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.
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hPso4/hPrp19: a critical component of DNA repair and DNA damage checkpoint complexes. Oncogene 2015; 35:2279-86. [PMID: 26364595 DOI: 10.1038/onc.2015.321] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Revised: 07/16/2015] [Accepted: 07/19/2015] [Indexed: 12/15/2022]
Abstract
Genome integrity is vital to cellular homeostasis and its forfeiture is linked to deleterious consequences-cancer, immunodeficiency, genetic disorders and premature aging. The human ubiquitin ligase Pso4/Prp19 has emerged as a critical component of multiple DNA damage response (DDR) signaling networks. It not only senses DNA damage, binds double-stranded DNA in a sequence-independent manner, facilitates processing of damaged DNA, promotes DNA end joining, regulates replication protein A (RPA2) phosphorylation and ubiquitination at damaged DNA, but also regulates RNA splicing and mitotic spindle formation in its integral capacity as a scaffold for a multimeric core complex. Accordingly, by virtue of its regulatory and structural interactions with key proteins critical for genome integrity-DNA double-strand break (DSB) repair, DNA interstrand crosslink repair, repair of stalled replication forks and DNA end joining-it fills a unique niche in restoring genomic integrity after multiple types of DNA damage and thus has a vital role in maintaining chromatin integrity and cellular functions. These properties may underlie its ability to thwart replicative senescence and, not surprisingly, have been linked to the self-renewal and colony-forming ability of murine hematopoietic stem cells. This review highlights recent advances in hPso4 research that provides a fascinating glimpse into the pleiotropic activities of a ubiquitously expressed multifunctional E3 ubiquitin ligase.
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46
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White ER, Sun L, Ma Z, Beckta JM, Danzig BA, Hacker DE, Huie M, Williams DC, Edwards RA, Valerie K, Mark Glover JN, Hartman MCT. Peptide library approach to uncover phosphomimetic inhibitors of the BRCA1 C-terminal domain. ACS Chem Biol 2015; 10:1198-208. [PMID: 25654734 PMCID: PMC4433557 DOI: 10.1021/cb500757u] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Many intracellular protein-protein interactions are mediated by the phosphorylation of serine, and phosphoserine-containing peptides can inhibit these interactions. However, hydrolysis of the phosphate by phosphatases, and the poor cell permeability associated with phosphorylated peptides has limited their utility in cellular and in vivo contexts. Compounding the problem, strategies to replace phosphoserine in peptide inhibitors with easily accessible mimetics (such as Glu or Asp) routinely fail. Here, we present an in vitro selection strategy for replacement of phosphoserine. Using mRNA display, we created a 10 trillion member structurally diverse unnatural peptide library. From this library, we found a peptide that specifically binds to the C-terminal domain (BRCT)2 of breast cancer associated protein 1 (BRCA1) with an affinity comparable to phosphorylated peptides. A crystal structure of the peptide bound reveals that the pSer-x-x-Phe motif normally found in BRCA1 (BRCT)2 binding partners is replaced by a Glu-x-x-4-fluoroPhe and that the peptide picks up additional contacts on the protein surface not observed in cognate phosphopeptide binding. Expression of the peptide in human cells led to defects in DNA repair by homologous recombination, a process BRCA1 is known to coordinate. Overall, this work validates a new in vitro selection approach for the development of inhibitors of protein-protein interactions mediated by serine phosphorylation.
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Affiliation(s)
- E. Railey White
- Department of Chemistry, Virginia Commonwealth University (VCU), 1001 West Main Street, P.O. Box 842006, Richmond, Virginia 23284, United States
- Massey Cancer Center, Virginia Commonwealth University, 401 College Street, Richmond, Virginia 23298, United States
| | - Luxin Sun
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - Zhong Ma
- Massey Cancer Center, Virginia Commonwealth University, 401 College Street, Richmond, Virginia 23298, United States
| | - Jason M. Beckta
- Massey Cancer Center, Virginia Commonwealth University, 401 College Street, Richmond, Virginia 23298, United States
- Department of Radiation Oncology, Virginia Commonwealth University, 401 College Street, Richmond, Virginia 23298, United States
| | - Brittany A. Danzig
- Department of Chemistry, Virginia Commonwealth University (VCU), 1001 West Main Street, P.O. Box 842006, Richmond, Virginia 23284, United States
- Massey Cancer Center, Virginia Commonwealth University, 401 College Street, Richmond, Virginia 23298, United States
| | - David E. Hacker
- Department of Chemistry, Virginia Commonwealth University (VCU), 1001 West Main Street, P.O. Box 842006, Richmond, Virginia 23284, United States
- Massey Cancer Center, Virginia Commonwealth University, 401 College Street, Richmond, Virginia 23298, United States
| | - Melissa Huie
- Massey Cancer Center, Virginia Commonwealth University, 401 College Street, Richmond, Virginia 23298, United States
| | - David C. Williams
- Massey Cancer Center, Virginia Commonwealth University, 401 College Street, Richmond, Virginia 23298, United States
- Department of Pathology, Virginia Commonwealth University, 401 College Street, Richmond, Virginia 23298, United States
| | - Ross A. Edwards
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - Kristoffer Valerie
- Massey Cancer Center, Virginia Commonwealth University, 401 College Street, Richmond, Virginia 23298, United States
- Department of Radiation Oncology, Virginia Commonwealth University, 401 College Street, Richmond, Virginia 23298, United States
| | - J. N. Mark Glover
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - Matthew C. T. Hartman
- Department of Chemistry, Virginia Commonwealth University (VCU), 1001 West Main Street, P.O. Box 842006, Richmond, Virginia 23284, United States
- Massey Cancer Center, Virginia Commonwealth University, 401 College Street, Richmond, Virginia 23298, United States
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47
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XRCC1 Polymorphisms and Urinary 8-Hydroxydeoxyguanine Levels Are Associated with Urothelial Carcinoma. PLoS One 2015; 10:e0124066. [PMID: 25938407 PMCID: PMC4418762 DOI: 10.1371/journal.pone.0124066] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 02/25/2015] [Indexed: 11/19/2022] Open
Abstract
The aim of this study was to examine the associations between the combined effects of urinary 8-Hydroxydeoxyguanine (8-OHdG) level and polymorphisms of XRCC1 Arg194Trp and XRCC1 Arg399Gln on the risk of urothelial carcinoma (UC). We conducted a hospital-based case-control study that included 168 cases of UC and 336 age- and gender-matched healthy controls. We used polymerase chain reaction and restriction fragment length polymorphism analyses to examine the genotypes of XRCC1 Arg194Trp and XRCC1 Arg399Gln. We used a competitive in vitro enzyme-linked immunosorbent assay to determine urinary 8-OHdG levels. The XRCC1 399 Gln/Gln genotype and the XRCC1 194 Arg/Arg genotype were positively correlated to UC (OR [95%CI] = 2.27 [1.20-4.27] and 1.59 [1.06-2.36], respectively). Urinary 8-OHdG levels were associated with UC in a dose-dependent manner. Participants with the XRCC1 (Arg399Gln) Gln/Gln genotype or the G-C/A-C haplotype of XRCC1 and a high urinary 8-OHdG level had a significantly higher risk of UC than those with the Arg/Arg + Arg/Gln genotype or the G-T haplotype and a low urinary 8-OHdG level. This is the first study to investigate the combined effect of urinary 8-OHdG level and XRCC1 polymorphisms on UC risk. The findings are especially meaningful for participants with XRCC1 399Gln or XRCC1 Arg194 genotypes and a high urinary 8-OHdG level, since these variables are associated with an increased risk of UC.
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48
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Abstract
The mammalian CtIP protein and its orthologs in other eukaryotes promote the resection of DNA double-strand breaks and are essential for meiotic recombination. Here we review the current literature supporting the role of CtIP in DNA end processing and the importance of CtIP endonuclease activity in DNA repair. We also examine the regulation of CtIP function by post-translational modifications, and its involvement in transcription- and replication-dependent functions through association with other protein complexes. The tumor suppressor function of CtIP likely is dependent on a combination of these roles in many aspects of DNA metabolism.
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49
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Wu Q, Jubb H, Blundell TL. Phosphopeptide interactions with BRCA1 BRCT domains: More than just a motif. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2015; 117:143-148. [PMID: 25701377 PMCID: PMC4728184 DOI: 10.1016/j.pbiomolbio.2015.02.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2014] [Revised: 01/05/2015] [Accepted: 02/10/2015] [Indexed: 01/15/2023]
Abstract
BRCA1 BRCT domains function as phosphoprotein-binding modules for recognition of the phosphorylated protein-sequence motif pSXXF. While the motif interaction interface provides strong anchor points for binding, protein regions outside the motif have recently been found to be important for binding affinity. In this review, we compare the available structural data for BRCA1 BRCT domains in complex with phosphopeptides in order to gain a more complete understanding of the interaction between phosphopeptides and BRCA1-BRCT domains.
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Affiliation(s)
- Qian Wu
- Department of Biochemistry, 80 Tennis Court Road, University of Cambridge, CB2 1GA, Cambridge, United Kingdom.
| | - Harry Jubb
- Department of Biochemistry, 80 Tennis Court Road, University of Cambridge, CB2 1GA, Cambridge, United Kingdom
| | - Tom L Blundell
- Department of Biochemistry, 80 Tennis Court Road, University of Cambridge, CB2 1GA, Cambridge, United Kingdom
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50
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Abraham S, Paknikar R, Bhumbra S, Luan D, Garg R, Dressler GR, Patel SR. The Groucho-associated phosphatase PPM1B displaces Pax transactivation domain interacting protein (PTIP) to switch the transcription factor Pax2 from a transcriptional activator to a repressor. J Biol Chem 2015; 290:7185-94. [PMID: 25631048 DOI: 10.1074/jbc.m114.607424] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Pax genes encode developmental regulatory proteins that specify cell lineages and tissues in metazoans. Upon binding to DNA through the conserved paired domain, Pax proteins can recruit both activating and repressing complexes that imprint distinct patterns of histone methylation associated with either gene activation or silencing. How the switch from Pax-mediated activation to repression is regulated remains poorly understood. In this report, we identify the phosphatase PPM1B as an essential component of the Groucho4 repressor complex that is recruited by Pax2 to chromatin. PPM1B can dephosphorylate the Pax2 activation domain and displace the adaptor protein PTIP, thus inhibiting H3K4 methylation and gene activation. Loss of PPM1B prevents Groucho-mediated gene repression. Thus, PPM1B helps switch Pax2 from a transcriptional activator to a repressor protein. This can have profound implications for developmental regulation by Pax proteins and suggests a model for imprinting specific epigenetic marks depending on the availability of co-factors.
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Affiliation(s)
| | | | | | - Danny Luan
- From the Departments of Internal Medicine and
| | - Rohan Garg
- From the Departments of Internal Medicine and
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