1
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Jirapongwattana N, Bunting SF, Ronning DR, Ghosal G, Karpf AR. RHNO1: at the crossroads of DNA replication stress, DNA repair, and cancer. Oncogene 2024; 43:2613-2620. [PMID: 39107463 DOI: 10.1038/s41388-024-03117-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2024] [Revised: 07/24/2024] [Accepted: 07/26/2024] [Indexed: 08/28/2024]
Abstract
The DNA replication stress (DRS) response is a crucial homeostatic mechanism for maintaining genome integrity in the face of intrinsic and extrinsic barriers to DNA replication. Importantly, DRS is often significantly increased in tumor cells, making tumors dependent on the cellular DRS response for growth and survival. Rad9-Hus1-Rad1 Interacting Nuclear Orphan 1 (RHNO1), a protein involved in the DRS response, has recently emerged as a potential therapeutic target in cancer. RHNO1 interacts with the 9-1-1 checkpoint clamp and TopBP1 to activate the ATR/Chk1 signaling pathway, the crucial mediator of the DRS response. Moreover, RHNO1 was also recently identified as a key facilitator of theta-mediated end joining (TMEJ), a DNA repair mechanism implicated in cancer progression and chemoresistance. In this literature review, we provide an overview of our current understanding of RHNO1, including its structure, function in the DRS response, and role in DNA repair, and discuss its potential as a cancer therapeutic target. Therapeutic targeting of RHNO1 holds promise for tumors with elevated DRS as well as tumors with DNA repair deficiencies, including homologous recombination DNA repair deficient (HRD) tumors. Further investigation into RHNO1 function in cancer, and development of approaches to target RHNO1, are expected to yield novel strategies for cancer treatment.
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Affiliation(s)
- Niphat Jirapongwattana
- Eppley Institute for Research in Cancer, University of Nebraska Medical Center, Omaha, NE, 68198-6805, USA
- Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, 68198-6805, USA
| | - Samuel F Bunting
- Department of Molecular Biology and Biochemistry, Rutgers, The State University of New Jersey, Piscataway, NJ, 08854-8021, USA
| | - Donald R Ronning
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE, 68198-6805, USA
| | - Gargi Ghosal
- Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, 68198-6805, USA
- Department of Genetics, Cell Biology, and Anatomy, University of Nebraska Medical Center, Omaha, NE, 68198-6805, USA
| | - Adam R Karpf
- Eppley Institute for Research in Cancer, University of Nebraska Medical Center, Omaha, NE, 68198-6805, USA.
- Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, 68198-6805, USA.
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2
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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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Chen B, Ren C, Ouyang Z, Xu J, Xu K, Li Y, Guo H, Bai X, Tian M, Xu X, Wang Y, Li H, Bo X, Chen H. Stratifying TAD boundaries pinpoints focal genomic regions of regulation, damage, and repair. Brief Bioinform 2024; 25:bbae306. [PMID: 38935071 PMCID: PMC11210073 DOI: 10.1093/bib/bbae306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 06/01/2024] [Accepted: 06/13/2024] [Indexed: 06/28/2024] Open
Abstract
Advances in chromatin mapping have exposed the complex chromatin hierarchical organization in mammals, including topologically associating domains (TADs) and their substructures, yet the functional implications of this hierarchy in gene regulation and disease progression are not fully elucidated. Our study delves into the phenomenon of shared TAD boundaries, which are pivotal in maintaining the hierarchical chromatin structure and regulating gene activity. By integrating high-resolution Hi-C data, chromatin accessibility, and DNA double-strand breaks (DSBs) data from various cell lines, we systematically explore the complex regulatory landscape at high-level TAD boundaries. Our findings indicate that these boundaries are not only key architectural elements but also vibrant hubs, enriched with functionally crucial genes and complex transcription factor binding site-clustered regions. Moreover, they exhibit a pronounced enrichment of DSBs, suggesting a nuanced interplay between transcriptional regulation and genomic stability. Our research provides novel insights into the intricate relationship between the 3D genome structure, gene regulation, and DNA repair mechanisms, highlighting the role of shared TAD boundaries in maintaining genomic integrity and resilience against perturbations. The implications of our findings extend to understanding the complexities of genomic diseases and open new avenues for therapeutic interventions targeting the structural and functional integrity of TAD boundaries.
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Affiliation(s)
- Bijia Chen
- Academy of Military Medical Sciences, Beijing 100850, China
| | - Chao Ren
- Academy of Military Medical Sciences, Beijing 100850, China
| | - Zhangyi Ouyang
- Academy of Military Medical Sciences, Beijing 100850, China
| | - Jingxuan Xu
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Gastrointestinal Surgery, Peking University Cancer Hospital & Institute, Beijing 100142, China
| | - Kang Xu
- School of Software, Shandong University, Jinan 250101, China
| | - Yaru Li
- Academy of Military Medical Sciences, Beijing 100850, China
| | - Hejiang Guo
- Academy of Military Medical Sciences, Beijing 100850, China
| | - Xuemei Bai
- Academy of Military Medical Sciences, Beijing 100850, China
| | - Mengge Tian
- The First Affiliated Hospital of Harbin Medical University, Harbin 150001, China
| | - Xiang Xu
- Academy of Military Medical Sciences, Beijing 100850, China
| | - Yuyang Wang
- College of Computer and Data Science, Fuzhou University, Fuzhou 350108, China
| | - Hao Li
- Academy of Military Medical Sciences, Beijing 100850, China
| | - Xiaochen Bo
- Academy of Military Medical Sciences, Beijing 100850, China
| | - Hebing Chen
- Academy of Military Medical Sciences, Beijing 100850, China
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4
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Yuan L, Liang X, He L. Insights into the Dissociation Process and Binding Pattern of the BRCT7/8-PHF8 Complex. ACS OMEGA 2024; 9:20819-20831. [PMID: 38764655 PMCID: PMC11097150 DOI: 10.1021/acsomega.3c09433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Revised: 02/27/2024] [Accepted: 04/24/2024] [Indexed: 05/21/2024]
Abstract
DNA topoisomerase 2-binding protein 1 (Topbp1) plays a crucial role in activating the ataxia-telangiectasia mutated and rad3-related (ATR) complex to initiate DNA damage repair responses. For this process to occur, it is necessary for PHF8 to dissociate from Topbp1. Topbp1 binds to the acidic patch sequence (APS) of PHF8 through its C-terminal BRCT7/8 domain, and disrupting this interaction could be a promising strategy for cancer treatment. To investigate the dissociation process and binding pattern of BRCT7/8-PHF8, we employed enhanced sampling techniques, such as steered molecular dynamics (SMD) simulations and accelerated molecular dynamics (aMD) simulations, along with self-organizing maps (SOM) and time-resolved force distribution analysis (TRFDA) methodologies. Our results demonstrate that the dissociation of PHF8 from BRCT7/8 starts from the N-terminus, leading to the unfolding of the N-terminal helix. Additionally, we identified critical residues that play a pivotal role in this dissociation process. These findings provide valuable insights into the disassociation of PHF8 from BRCT7/8, which could potentially guide the development of novel drugs targeting Topbp1 for cancer therapy.
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Affiliation(s)
- Longxiao Yuan
- State
Key Laboratory of Medicinal Chemical Biology, College of Pharmacy, Nankai University, Tianjin 300353, China
| | - Xiaodan Liang
- School
of Computer Sciences and Technology, Tiangong
University, Tianjin 300387, China
| | - Lei He
- Institute
for Fetology, The First Affiliated Hospital
of Soochow University, Suzhou 215006, China
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5
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Tatsukawa K, Sakamoto R, Kawasoe Y, Kubota Y, Tsurimoto T, Takahashi T, Ohashi E. Resection of DNA double-strand breaks activates Mre11-Rad50-Nbs1- and Rad9-Hus1-Rad1-dependent mechanisms that redundantly promote ATR checkpoint activation and end processing in Xenopus egg extracts. Nucleic Acids Res 2024; 52:3146-3163. [PMID: 38349040 PMCID: PMC11014350 DOI: 10.1093/nar/gkae082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 01/21/2024] [Accepted: 01/29/2024] [Indexed: 04/14/2024] Open
Abstract
Sensing and processing of DNA double-strand breaks (DSBs) are vital to genome stability. DSBs are primarily detected by the ATM checkpoint pathway, where the Mre11-Rad50-Nbs1 (MRN) complex serves as the DSB sensor. Subsequent DSB end resection activates the ATR checkpoint pathway, where replication protein A, MRN, and the Rad9-Hus1-Rad1 (9-1-1) clamp serve as the DNA structure sensors. ATR activation depends also on Topbp1, which is loaded onto DNA through multiple mechanisms. While different DNA structures elicit specific ATR-activation subpathways, the regulation and mechanisms of the ATR-activation subpathways are not fully understood. Using DNA substrates that mimic extensively resected DSBs, we show here that MRN and 9-1-1 redundantly stimulate Dna2-dependent long-range end resection and ATR activation in Xenopus egg extracts. MRN serves as the loading platform for ATM, which, in turn, stimulates Dna2- and Topbp1-loading. Nevertheless, MRN promotes Dna2-mediated end processing largely independently of ATM. 9-1-1 is dispensable for bulk Dna2 loading, and Topbp1 loading is interdependent with 9-1-1. ATR facilitates Mre11 phosphorylation and ATM dissociation. These data uncover that long-range end resection activates two redundant pathways that facilitate ATR checkpoint signaling and DNA processing in a vertebrate system.
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Affiliation(s)
- Kensuke Tatsukawa
- Graduate School of Systems Life Sciences, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Reihi Sakamoto
- Graduate School of Systems Life Sciences, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Yoshitaka Kawasoe
- Faculty of Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Yumiko Kubota
- Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan
| | - Toshiki Tsurimoto
- Faculty of Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Tatsuro S Takahashi
- Faculty of Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Eiji Ohashi
- Faculty of Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
- Nagahama Institute of Bio-Science and Technology, 1266 Tamura-cho, Nagahama, Shiga 526-0829, Japan
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6
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Wendel S, Wallace NA. Interactions among human papillomavirus proteins and host DNA repair factors differ during the viral life cycle and virus-induced tumorigenesis. mSphere 2023; 8:e0042723. [PMID: 37850786 PMCID: PMC10732048 DOI: 10.1128/msphere.00427-23] [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: 10/19/2023] Open
Abstract
This review focuses on the impact of human papillomavirus (HPV) oncogenes on DNA repair pathways with a particular focus on how these relationships change as productive HPV infections transition to malignant lesions. We made specific efforts to incorporate advances in the understanding of HPV and DNA damage repair over the last 4 years. We apologize for any articles that we missed in compiling this report.
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Affiliation(s)
- Sebastian Wendel
- Kansas State University, Division of Biology, Manhattan, Kansas, USA
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7
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Ummethum H, Li J, Lisby M, Oestergaard V. Emerging roles of the CIP2A-TopBP1 complex in genome integrity. NAR Cancer 2023; 5:zcad052. [PMID: 37829116 PMCID: PMC10566317 DOI: 10.1093/narcan/zcad052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2023] [Revised: 08/27/2023] [Accepted: 09/24/2023] [Indexed: 10/14/2023] Open
Abstract
CIP2A is an inhibitor of the tumour suppressor protein phosphatase 2A. Recently, CIP2A was identified as a synthetic lethal interactor of BRCA1 and BRCA2 and a driver of basal-like breast cancers. In addition, a joint role of TopBP1 (topoisomerase IIβ-binding protein 1) and CIP2A for maintaining genome integrity during mitosis was discovered. TopBP1 has multiple functions as it is a scaffold for proteins involved in DNA replication, transcriptional regulation, cell cycle regulation and DNA repair. Here, we briefly review details of the CIP2A-TopBP1 interaction, its role in maintaining genome integrity, its involvement in cancer and its potential as a therapeutic target.
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Affiliation(s)
- Henning Ummethum
- Department of Biology, University of Copenhagen, Copenhagen 2200, Denmark
| | - Jiayi Li
- Department of Biology, University of Copenhagen, Copenhagen 2200, Denmark
| | - Michael Lisby
- Department of Biology, University of Copenhagen, Copenhagen 2200, Denmark
| | - Vibe H Oestergaard
- Department of Biology, University of Copenhagen, Copenhagen 2200, Denmark
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8
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Wang ZQ, Zhang ZC, Wu YY, Pi YN, Lou SH, Liu TB, Lou G, Yang C. Bromodomain and extraterminal (BET) proteins: biological functions, diseases, and targeted therapy. Signal Transduct Target Ther 2023; 8:420. [PMID: 37926722 PMCID: PMC10625992 DOI: 10.1038/s41392-023-01647-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 08/23/2023] [Accepted: 09/12/2023] [Indexed: 11/07/2023] Open
Abstract
BET proteins, which influence gene expression and contribute to the development of cancer, are epigenetic interpreters. Thus, BET inhibitors represent a novel form of epigenetic anticancer treatment. Although preliminary clinical trials have shown the anticancer potential of BET inhibitors, it appears that these drugs have limited effectiveness when used alone. Therefore, given the limited monotherapeutic activity of BET inhibitors, their use in combination with other drugs warrants attention, including the meaningful variations in pharmacodynamic activity among chosen drug combinations. In this paper, we review the function of BET proteins, the preclinical justification for BET protein targeting in cancer, recent advances in small-molecule BET inhibitors, and preliminary clinical trial findings. We elucidate BET inhibitor resistance mechanisms, shed light on the associated adverse events, investigate the potential of combining these inhibitors with diverse therapeutic agents, present a comprehensive compilation of synergistic treatments involving BET inhibitors, and provide an outlook on their future prospects as potent antitumor agents. We conclude by suggesting that combining BET inhibitors with other anticancer drugs and innovative next-generation agents holds great potential for advancing the effective targeting of BET proteins as a promising anticancer strategy.
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Affiliation(s)
- Zhi-Qiang Wang
- Department of Gynecology Oncology, Harbin Medical University Cancer Hospital, Harbin, 150086, China
| | - Zhao-Cong Zhang
- Department of Gynecology Oncology, Harbin Medical University Cancer Hospital, Harbin, 150086, China
| | - Yu-Yang Wu
- School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Ya-Nan Pi
- Department of Gynecology Oncology, Harbin Medical University Cancer Hospital, Harbin, 150086, China
| | - Sheng-Han Lou
- Department of Colorectal Surgery, Harbin Medical University Cancer Hospital, Harbin, China
| | - Tian-Bo Liu
- Department of Gynecology Oncology, Harbin Medical University Cancer Hospital, Harbin, 150086, China
| | - Ge Lou
- Department of Gynecology Oncology, Harbin Medical University Cancer Hospital, Harbin, 150086, China.
| | - Chang Yang
- Department of Gynecology Oncology, Harbin Medical University Cancer Hospital, Harbin, 150086, China.
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9
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Lin FT, Liu K, Garan LAW, Folly-Kossi H, Song Y, Lin SJ, Lin WC. A small-molecule inhibitor of TopBP1 exerts anti-MYC activity and synergy with PARP inhibitors. Proc Natl Acad Sci U S A 2023; 120:e2307793120. [PMID: 37878724 PMCID: PMC10622895 DOI: 10.1073/pnas.2307793120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 09/19/2023] [Indexed: 10/27/2023] Open
Abstract
We have previously identified TopBP1 (topoisomerase IIβ-binding protein 1) as a promising target for cancer therapy, given its role in the convergence of Rb, PI(3)K/Akt, and p53 pathways. Based on this, we conducted a large-scale molecular docking screening to identify a small-molecule inhibitor that specifically targets the BRCT7/8 domains of TopBP1, which we have named 5D4. Our studies show that 5D4 inhibits TopBP1 interactions with E2F1, mutant p53, and Cancerous Inhibitor of Protein Phosphatase 2A. This leads to the activation of E2F1-mediated apoptosis and the inhibition of mutant p53 gain of function. In addition, 5D4 disrupts the interaction of TopBP1 with MIZ1, which in turn allows MIZ1 to bind to its target gene promoters and repress MYC activity. Moreover, 5D4 inhibits the association of the TopBP1-PLK1 complex and prevents the formation of Rad51 foci. When combined with inhibitors of PARP1/2 or PARP14, 5D4 synergizes to effectively block cancer cell proliferation. Our animal studies have demonstrated the antitumor activity of 5D4 in breast and ovarian cancer xenograft models. Moreover, the effectiveness of 5D4 is further enhanced when combined with a PARP1/2 inhibitor talazoparib. Taken together, our findings strongly support the potential use of TopBP1-BRCT7/8 inhibitors as a targeted cancer therapy.
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Affiliation(s)
- Fang-Tsyr Lin
- Section of Hematology/Oncology, Department of Medicine, Baylor College of Medicine, Houston, TX77030
- Dan L. Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, TX77030
| | - Kang Liu
- Section of Hematology/Oncology, Department of Medicine, Baylor College of Medicine, Houston, TX77030
| | - Lidija A. Wilhelms Garan
- Section of Hematology/Oncology, Department of Medicine, Baylor College of Medicine, Houston, TX77030
- Cancer and Cell Biology Graduate Program, Baylor College of Medicine, Houston, TX77030
| | - Helena Folly-Kossi
- Section of Hematology/Oncology, Department of Medicine, Baylor College of Medicine, Houston, TX77030
| | - Yongcheng Song
- Department of Pharmacology, Baylor College of Medicine, Houston, TX77030
| | - Shwu-Jiuan Lin
- Department of Pharmaceutical Sciences, School of Pharmacy, Taipei Medical University, Taipei11031, Taiwan
- PhD Program in Clinical Drug Development of Herbal Medicine, College of Pharmacy, Taipei Medical University, Taipei 11031, Taiwan
| | - Weei-Chin Lin
- Section of Hematology/Oncology, Department of Medicine, Baylor College of Medicine, Houston, TX77030
- Dan L. Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, TX77030
- Cancer and Cell Biology Graduate Program, Baylor College of Medicine, Houston, TX77030
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX77030
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10
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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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11
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Mota MBS, Woods NT, Carvalho MA, Monteiro ANA, Mesquita RD. Evolution of the triplet BRCT domain. DNA Repair (Amst) 2023; 129:103532. [PMID: 37453244 DOI: 10.1016/j.dnarep.2023.103532] [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: 02/06/2023] [Revised: 06/28/2023] [Accepted: 07/01/2023] [Indexed: 07/18/2023]
Abstract
Organisms have evolved a complex system, called the DNA damage response (DDR), which maintains genome integrity. The DDR is responsible for identifying and repairing a variety of lesions and alterations in DNA. DDR proteins coordinate DNA damage detection, cell cycle arrest, and repair, with many of these events regulated by protein phosphorylation. In the human proteome, 23 proteins contain the BRCT (BRCA1 C-Terminus domain) domain, a modular signaling domain that can bind phosphopeptides and mediate protein-protein interactions. BRCTs can be found as functional single units, tandem (tBRCT), triplet (tpBRCT), and quartet. Here we examine the evolution of the tpBRCT architecture present in TOPBP1 (DNA topoisomerase II binding protein 1) and ECT2 (epithelial cell transforming 2), and their respective interaction partners RAD9 (Cell cycle checkpoint control protein RAD9) and CYK-4 (Rac GTPase-activating protein 1), with a focus on the conservation of the phosphopeptide-binding residues. The pair TOPBP1-RAD9 arose with the Eukaryotes and ECT2-CYK-4 with the Eumetazoans. Triplet structural and functional characteristics were conserved in almost all organisms. The first unit of the triplet (BRCT0) is different from the other two BRCTs but conserved between orthologs for both TOPBP1 and ECT2. BRCT domain evolution simulations suggest a trend to retain the singlet or towards two or three BRCT copies per protein consistent with functional tBRCT and tpBRCT architectures. Our results shed light on the emergence of the function and architecture of multiple BRCT domain organizations and provide information about the evolution of the BRCT triplet. Knowledge of BRCT domain evolution can improve the understanding of DNA damage response mechanisms and signal transduction in DDR.
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Affiliation(s)
- M B S Mota
- Departamento de Bioquímica, Instituto de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - N T Woods
- Eppley Institute, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - M A Carvalho
- Instituto Federal de Educação, Ciência e Tecnologia do Rio de Janeiro, RJ, Brazil; Instituto Nacional de Câncer, Rio de Janeiro, RJ, Brazil
| | - A N A Monteiro
- Cancer Epidemiology Program, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL 33612, USA
| | - R D Mesquita
- Departamento de Bioquímica, Instituto de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
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12
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Gelot C, Kovacs MT, Miron S, Mylne E, Haan A, Boeffard-Dosierre L, Ghouil R, Popova T, Dingli F, Loew D, Guirouilh-Barbat J, Del Nery E, Zinn-Justin S, Ceccaldi R. Polθ is phosphorylated by PLK1 to repair double-strand breaks in mitosis. Nature 2023; 621:415-422. [PMID: 37674080 PMCID: PMC10499603 DOI: 10.1038/s41586-023-06506-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 08/01/2023] [Indexed: 09/08/2023]
Abstract
DNA double-strand breaks (DSBs) are deleterious lesions that challenge genome integrity. To mitigate this threat, human cells rely on the activity of multiple DNA repair machineries that are tightly regulated throughout the cell cycle1. In interphase, DSBs are mainly repaired by non-homologous end joining and homologous recombination2. However, these pathways are completely inhibited in mitosis3-5, leaving the fate of mitotic DSBs unknown. Here we show that DNA polymerase theta6 (Polθ) repairs mitotic DSBs and thereby maintains genome integrity. In contrast to other DSB repair factors, Polθ function is activated in mitosis upon phosphorylation by Polo-like kinase 1 (PLK1). Phosphorylated Polθ is recruited by a direct interaction with the BRCA1 C-terminal domains of TOPBP1 to mitotic DSBs, where it mediates joining of broken DNA ends. Loss of Polθ leads to defective repair of mitotic DSBs, resulting in a loss of genome integrity. This is further exacerbated in cells that are deficient in homologous recombination, where loss of mitotic DSB repair by Polθ results in cell death. Our results identify mitotic DSB repair as the underlying cause of synthetic lethality between Polθ and homologous recombination. Together, our findings reveal the critical importance of mitotic DSB repair in the maintenance of genome integrity.
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Affiliation(s)
- Camille Gelot
- INSERM U830, PSL Research University, Institut Curie, Paris, France
| | | | - Simona Miron
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Paris-Saclay University, Gif-sur-Yvette, France
| | - Emilie Mylne
- INSERM U830, PSL Research University, Institut Curie, Paris, France
| | - Alexis Haan
- INSERM U830, PSL Research University, Institut Curie, Paris, France
| | - Liza Boeffard-Dosierre
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Paris-Saclay University, Gif-sur-Yvette, France
| | - Rania Ghouil
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Paris-Saclay University, Gif-sur-Yvette, France
| | - Tatiana Popova
- INSERM U830, DNA Repair and Uveal Melanoma (D.R.U.M.), Equipe labellisée par la Ligue Nationale Contre le Cancer, PSL Research University, Institut Curie, Paris, France
| | - Florent Dingli
- CurieCoreTech Mass Spectrometry Proteomics, Institut Curie, PSL Research University, Paris, France
| | - Damarys Loew
- CurieCoreTech Mass Spectrometry Proteomics, Institut Curie, PSL Research University, Paris, France
| | - Josée Guirouilh-Barbat
- Université de Paris, INSERM U1016, UMR 8104 CNRS, Equipe Labellisée Ligue Nationale Contre le Cancer, Institut Cochin, Paris, France
| | - Elaine Del Nery
- Department of Translational Research-Biophenics High-Content Screening Laboratory, Cell and Tissue Imaging Facility (PICT-IBiSA), PSL Research University, Institut Curie, Paris, France
| | - Sophie Zinn-Justin
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Paris-Saclay University, Gif-sur-Yvette, France
| | - Raphael Ceccaldi
- INSERM U830, PSL Research University, Institut Curie, Paris, France.
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13
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Haccard O, Ciardo D, Narrissamprakash H, Bronchain O, Kumagai A, Dunphy WG, Goldar A, Marheineke K. Rif1 restrains the rate of replication origin firing in Xenopus laevis. Commun Biol 2023; 6:788. [PMID: 37516798 PMCID: PMC10387115 DOI: 10.1038/s42003-023-05172-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 07/24/2023] [Indexed: 07/31/2023] Open
Abstract
Metazoan genomes are duplicated by the coordinated activation of clusters of replication origins at different times during S phase, but the underlying mechanisms of this temporal program remain unclear during early development. Rif1, a key replication timing factor, inhibits origin firing by recruiting protein phosphatase 1 (PP1) to chromatin counteracting S phase kinases. We have previously described that Rif1 depletion accelerates early Xenopus laevis embryonic cell cycles. Here, we find that in the absence of Rif1, patterns of replication foci change along with the acceleration of replication cluster activation. However, initiations increase only moderately inside active clusters. Our numerical simulations suggest that the absence of Rif1 compresses the temporal program towards more homogeneity and increases the availability of limiting initiation factors. We experimentally demonstrate that Rif1 depletion increases the chromatin-binding of the S phase kinase Cdc7/Drf1, the firing factors Treslin, MTBP, Cdc45, RecQL4, and the phosphorylation of both Treslin and MTBP. We show that Rif1 globally, but not locally, restrains the replication program in early embryos, possibly by inhibiting or excluding replication factors from chromatin.
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Affiliation(s)
- Olivier Haccard
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Diletta Ciardo
- Institut de Biologie de l'Ecole Normale Supérieure, Ecole Normale Supérieure, CNRS, INSERM, PSL Research University, Paris, France
| | - Hemalatha Narrissamprakash
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Odile Bronchain
- Paris-Saclay Institute of Neuroscience, CNRS, Université Paris-Saclay, CERTO-Retina France, 91400, Saclay, France
| | - Akiko Kumagai
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - William G Dunphy
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Arach Goldar
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Kathrin Marheineke
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France.
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14
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Peña-Guerrero J, Fernández-Rubio C, García-Sosa AT, Nguewa PA. BRCT Domains: Structure, Functions, and Implications in Disease-New Therapeutic Targets for Innovative Drug Discovery against Infections. Pharmaceutics 2023; 15:1839. [PMID: 37514027 PMCID: PMC10386641 DOI: 10.3390/pharmaceutics15071839] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 06/12/2023] [Accepted: 06/22/2023] [Indexed: 07/30/2023] Open
Abstract
The search for new therapeutic targets and their implications in drug development remains an emerging scientific topic. BRCT-bearing proteins are found in Archaea, Bacteria, Eukarya, and viruses. They are traditionally involved in DNA repair, recombination, and cell cycle control. To carry out these functions, BRCT domains are able to interact with DNA and proteins. Moreover, such domains are also implicated in several pathogenic processes and malignancies including breast, ovarian, and lung cancer. Although these domains exhibit moderately conserved folding, their sequences show very low conservation. Interestingly, sequence variations among species are considered positive traits in the search for suitable therapeutic targets, since non-specific drug interactions might be reduced. These main characteristics of BRCT, as well as its critical implications in key biological processes in the cell, have prompted the study of these domains as therapeutic targets. This review explores the possible roles of BRCT domains as therapeutic targets for drug discovery. We describe their common structural features and relevant interactions and pathways, as well as their implications in pathologic processes. Drugs commonly used to target these domains are also presented. Finally, based on their structures, we describe new drug design possibilities using modern and innovative techniques.
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Affiliation(s)
- José Peña-Guerrero
- ISTUN Institute of Tropical Health, Department of Microbiology and Parasitology, University of Navarra, IdiSNA (Navarra Institute for Health Research), E-31008 Pamplona, Navarra, Spain
| | - Celia Fernández-Rubio
- ISTUN Institute of Tropical Health, Department of Microbiology and Parasitology, University of Navarra, IdiSNA (Navarra Institute for Health Research), E-31008 Pamplona, Navarra, Spain
| | - Alfonso T García-Sosa
- Chair of Molecular Technology, Institute of Chemistry, University of Tartu, Ravila 14a, 50411 Tartu, Estonia
| | - Paul A Nguewa
- ISTUN Institute of Tropical Health, Department of Microbiology and Parasitology, University of Navarra, IdiSNA (Navarra Institute for Health Research), E-31008 Pamplona, Navarra, Spain
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15
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Trivedi P, Steele CD, Au FKC, Alexandrov LB, Cleveland DW. Mitotic tethering enables inheritance of shattered micronuclear chromosomes. Nature 2023; 618:1049-1056. [PMID: 37316668 PMCID: PMC10424572 DOI: 10.1038/s41586-023-06216-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 05/12/2023] [Indexed: 06/16/2023]
Abstract
Chromothripsis, the shattering and imperfect reassembly of one (or a few) chromosome(s)1, is an ubiquitous2 mutational process generating localized and complex chromosomal rearrangements that drive genome evolution in cancer. Chromothripsis can be initiated by mis-segregation errors in mitosis3,4 or DNA metabolism5-7 that lead to entrapment of chromosomes within micronuclei and their subsequent fragmentation in the next interphase or following mitotic entry6,8-10. Here we use inducible degrons to demonstrate that chromothriptically produced pieces of a micronucleated chromosome are tethered together in mitosis by a protein complex consisting of mediator of DNA damage checkpoint 1 (MDC1), DNA topoisomerase II-binding protein 1 (TOPBP1) and cellular inhibitor of PP2A (CIP2A), thereby enabling en masse segregation to the same daughter cell. Such tethering is shown to be crucial for the viability of cells undergoing chromosome mis-segregation and shattering after transient inactivation of the spindle assembly checkpoint. Transient, degron-induced reduction in CIP2A following chromosome micronucleation-dependent chromosome shattering is shown to drive acquisition of segmental deletions and inversions. Analyses of pancancer tumour genomes showed that expression of CIP2A and TOPBP1 was increased overall in cancers with genomic rearrangements, including copy number-neutral chromothripsis with minimal deletions, but comparatively reduced in cancers with canonical chromothripsis in which deletions were frequent. Thus, chromatin-bound tethers maintain the proximity of fragments of a shattered chromosome enabling their re-encapsulation into, and religation within, a daughter cell nucleus to form heritable, chromothriptically rearranged chromosomes found in the majority of human cancers.
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Affiliation(s)
- Prasad Trivedi
- Ludwig Institute for Cancer Research, University of California at San Diego, La Jolla, CA, USA
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA, USA
| | - Christopher D Steele
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA, USA
- Department of Bioengineering, University of California at San Diego, La Jolla, CA, USA
- Moores Cancer Center, University of California at San Diego, La Jolla, CA, USA
| | - Franco K C Au
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA, USA
| | - Ludmil B Alexandrov
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA, USA
- Department of Bioengineering, University of California at San Diego, La Jolla, CA, USA
- Moores Cancer Center, University of California at San Diego, La Jolla, CA, USA
| | - Don W Cleveland
- Ludwig Institute for Cancer Research, University of California at San Diego, La Jolla, CA, USA.
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA, USA.
- Moores Cancer Center, University of California at San Diego, La Jolla, CA, USA.
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16
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Nechay M, Kleiner RE. Oxaliplatin Inhibits RNA Polymerase I via DNA Damage Signaling Targeted to the Nucleolus. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.02.535301. [PMID: 37066425 PMCID: PMC10103995 DOI: 10.1101/2023.04.02.535301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/18/2023]
Abstract
Platinum (Pt) compounds are an important class of anti-cancer therapeutics, but outstanding questions remain regarding their mode of action. In particular, emerging evidence indicates that oxaliplatin, a Pt drug used to treat colorectal cancer, kills cells by inducing ribosome biogenesis stress rather than through DNA damage generation, but the underlying mechanism is unknown. Here, we demonstrate that oxaliplatin-induced ribosomal RNA (rRNA) transcriptional silencing and nucleolar stress occur downstream of DNA damage signaling involving ATM and ATR. We show that NBS1 and TOPBP1, two proteins involved in the nucleolar DNA damage response (n-DDR), are recruited to nucleoli upon oxaliplatin treatment. However, we find that rRNA transcriptional inhibition by oxaliplatin does not depend upon NBS1 or TOPBP1, nor does oxaliplatin induce substantial amounts of nucleolar DNA damage, distinguishing it from previously characterized n-DDR pathways. Taken together, our work indicates that oxaliplatin induces a distinct DDR signaling pathway that functions in trans to inhibit Pol I transcription in the nucleolus, demonstrating how nucleolar stress can be linked to DNA damage signaling and highlighting an important mechanism of Pt drug cytotoxicity.
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17
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Huynh O, Ruis K, Montales K, Michael WM. NBS1 binds directly to TOPBP1 via disparate interactions between the NBS1 BRCT1 domain and the TOPBP1 BRCT1 and BRCT2 domains. DNA Repair (Amst) 2023; 123:103461. [PMID: 36738687 PMCID: PMC9992324 DOI: 10.1016/j.dnarep.2023.103461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 01/20/2023] [Accepted: 01/26/2023] [Indexed: 02/05/2023]
Abstract
The TOPBP1 and NBS1 proteins are key components of DNA repair and DNA-based signaling systems. TOPBP1 is a multi-BRCT domain containing protein that plays important roles in checkpoint signaling, DNA replication, and DNA repair. Likewise, NBS1, which is a component of the MRE11-RAD50-NBS1 (MRN) complex, functions in both checkpoint signaling and DNA repair. NBS1 also contains BRCT domains, and previous works have shown that TOPBP1 and NBS1 interact with one another. In this work we examine the interaction between TOPBP1 and NBS1 in detail. We report that NBS1 uses its BRCT1 domain to interact with TOPBP1's BRCT1 domain and, separately, with TOPBP1's BRCT2 domain. Thus, NBS1 can make two distinct contacts with TOPBP1. We report that recombinant TOPBP1 and NBS1 proteins bind one another in a purified system, showing that the interaction is direct and does not require post-translational modifications. Surprisingly, we also report that intact BRCT domains are not required for these interactions, as truncated versions of the domains are sufficient to confer binding. For TOPBP1, we find that small 24-29 amino acid sequences within BRCT1 or BRCT2 allow binding to NBS1, in a transferrable manner. These data expand our knowledge of how the crucial DNA damage response proteins TOPBP1 and NBS1 interact with one another and set the stage for functional analysis of the two disparate binding sites for NBS1 on TOPBP1.
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Affiliation(s)
- Oanh Huynh
- Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Kenna Ruis
- Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Katrina Montales
- Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - W Matthew Michael
- Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA.
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18
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Zhao Y, Huang X, Zhu D, Wei M, Luo J, Yu S, Tian Y, Zheng X. Deubiquitinase OTUD6A promotes breast cancer progression by increasing TopBP1 stability and rendering tumor cells resistant to DNA-damaging therapy. Cell Death Differ 2022; 29:2531-2544. [PMID: 35768646 PMCID: PMC9751275 DOI: 10.1038/s41418-022-01036-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 06/14/2022] [Accepted: 06/15/2022] [Indexed: 01/31/2023] Open
Abstract
The DNA damage response (DDR) is critical for maintaining cellular homeostasis and genome integrity. Mounting evidence has shown that posttranslational protein modifications play vital roles in the DDR. In this study, we showed that deubiquitinase OTUD6A is involved in the DDR and is important for maintaining genomic stability. Mechanistically, in response to DNA damage, the abundance of OTUD6A was increased; meanwhile, PP2A interacted with OTUD6A and dephosphorylated OTUD6A at sites S70/71/74, which promoted nuclear localization of OTUD6A. Subsequently, OTUD6A was recruited to the damage site, where it interacted with TopBP1 and blocked the interaction between TopBP1 and its ubiquitin E3 ligase UBR5, decreasing K48-linked polyubiquitination and increasing the stability of TopBP1. OTUD6A depletion impaired CHK1 S345 phosphorylation and blocked cell cycle progression under DNA replication stress. Consistently, knockout of OTUD6A rendered mice hypersensitive to irradiation, shortened survival, and inhibited tumor growth by regulating TopBP1 in xenografted nude mice. Moreover, OTUD6A is expressed at high levels in breast cancer, and OTUD6A overexpression promotes cell proliferation, migration and invasion, indicating that dysregulation of OTUD6A expression contributes to genomic instability and is associated with tumor development. In summary, this study demonstrates that OTUD6A plays a critical role in promoting tumor cell resistance to chemoradiotherapy by deubiquitinating and stabilizing TopBP1.
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Affiliation(s)
- Yan Zhao
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
- Department of Biochemistry and Molecular Biology, School of Life Sciences, Peking University, Beijing, China
| | - Xinping Huang
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
- Department of Biochemistry and Molecular Biology, School of Life Sciences, Peking University, Beijing, China
| | - Dan Zhu
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
- Department of Biochemistry and Molecular Biology, School of Life Sciences, Peking University, Beijing, China
| | - Min Wei
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
- Department of Biochemistry and Molecular Biology, School of Life Sciences, Peking University, Beijing, China
| | - Jiechen Luo
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
- Department of Biochemistry and Molecular Biology, School of Life Sciences, Peking University, Beijing, China
| | - Shuyu Yu
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
- Department of Biochemistry and Molecular Biology, School of Life Sciences, Peking University, Beijing, China
| | - Yonglu Tian
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China
| | - Xiaofeng Zheng
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China.
- Department of Biochemistry and Molecular Biology, School of Life Sciences, Peking University, Beijing, China.
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19
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Zhang J, Pei J, Durham J, Bos T, Cong Q. Computed cancer interactome explains the effects of somatic mutations in cancers. Protein Sci 2022; 31:e4479. [PMID: 36261849 PMCID: PMC9667826 DOI: 10.1002/pro.4479] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 09/28/2022] [Accepted: 10/13/2022] [Indexed: 12/13/2022]
Abstract
Protein-protein interactions (PPIs) are involved in almost all essential cellular processes. Perturbation of PPI networks plays critical roles in tumorigenesis, cancer progression, and metastasis. While numerous high-throughput experiments have produced a vast amount of data for PPIs, these data sets suffer from high false positive rates and exhibit a high degree of discrepancy. Coevolution of amino acid positions between protein pairs has proven to be useful in identifying interacting proteins and providing structural details of the interaction interfaces with the help of deep learning methods like AlphaFold (AF). In this study, we applied AF to investigate the cancer protein-protein interactome. We predicted 1,798 PPIs for cancer driver proteins involved in diverse cellular processes such as transcription regulation, signal transduction, DNA repair, and cell cycle. We modeled the spatial structures for the predicted binary protein complexes, 1,087 of which lacked previous 3D structure information. Our predictions offer novel structural insight into many cancer-related processes such as the MAP kinase cascade and Fanconi anemia pathway. We further investigated the cancer mutation landscape by mapping somatic missense mutations (SMMs) in cancer to the predicted PPI interfaces and performing enrichment and depletion analyses. Interfaces enriched or depleted with SMMs exhibit different preferences for functional categories. Interfaces enriched in mutations tend to function in pathways that are deregulated in cancers and they may help explain the molecular mechanisms of cancers in patients; interfaces lacking mutations appear to be essential for the survival of cancer cells and thus may be future targets for PPI modulating drugs.
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Affiliation(s)
- Jing Zhang
- Eugene McDermott Center for Human Growth and DevelopmentUniversity of Texas Southwestern Medical CenterDallasTexasUSA
- Department of BiophysicsUniversity of Texas Southwestern Medical CenterDallasTexasUSA
| | - Jimin Pei
- Eugene McDermott Center for Human Growth and DevelopmentUniversity of Texas Southwestern Medical CenterDallasTexasUSA
- Department of BiophysicsUniversity of Texas Southwestern Medical CenterDallasTexasUSA
| | - Jesse Durham
- Eugene McDermott Center for Human Growth and DevelopmentUniversity of Texas Southwestern Medical CenterDallasTexasUSA
- Department of BiophysicsUniversity of Texas Southwestern Medical CenterDallasTexasUSA
| | - Tasia Bos
- Eugene McDermott Center for Human Growth and DevelopmentUniversity of Texas Southwestern Medical CenterDallasTexasUSA
- Department of BiophysicsUniversity of Texas Southwestern Medical CenterDallasTexasUSA
| | - Qian Cong
- Eugene McDermott Center for Human Growth and DevelopmentUniversity of Texas Southwestern Medical CenterDallasTexasUSA
- Department of BiophysicsUniversity of Texas Southwestern Medical CenterDallasTexasUSA
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20
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Day M, Oliver AW, Pearl LH. Structure of the human RAD17-RFC clamp loader and 9-1-1 checkpoint clamp bound to a dsDNA-ssDNA junction. Nucleic Acids Res 2022; 50:8279-8289. [PMID: 35819203 PMCID: PMC9371934 DOI: 10.1093/nar/gkac588] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 06/20/2022] [Accepted: 06/27/2022] [Indexed: 11/14/2022] Open
Abstract
The RAD9-RAD1-HUS1 (9-1-1) clamp forms one half of the DNA damage checkpoint system that signals the presence of substantial regions of single-stranded DNA arising from replication fork collapse or resection of DNA double strand breaks. Loaded at the 5'-recessed end of a dsDNA-ssDNA junction by the RAD17-RFC clamp loader complex, the phosphorylated C-terminal tail of the RAD9 subunit of 9-1-1 engages with the mediator scaffold TOPBP1 which in turn activates the ATR kinase, localised through the interaction of its constitutive partner ATRIP with RPA-coated ssDNA. Using cryogenic electron microscopy (cryoEM) we have determined the structure of a complex of the human RAD17-RFC clamp loader bound to human 9-1-1, engaged with a dsDNA-ssDNA junction. The structure answers the key questions of how RAD17 confers specificity for 9-1-1 over PCNA, and how the clamp loader specifically recognises the recessed 5' DNA end and fixes the orientation of 9-1-1 on the ssDNA.
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Affiliation(s)
- Matthew Day
- Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK
| | - Antony W Oliver
- Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK
| | - Laurence H Pearl
- Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK
- Division of Structural Biology, Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London SW1E 6BT, UK
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21
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Montales K, Ruis K, Lindsay H, Michael WM. MRN-dependent and independent pathways for recruitment of TOPBP1 to DNA double-strand breaks. PLoS One 2022; 17:e0271905. [PMID: 35917319 PMCID: PMC9345342 DOI: 10.1371/journal.pone.0271905] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 07/08/2022] [Indexed: 12/31/2022] Open
Abstract
Ataxia Telangiectasia mutated and RAD3-related (ATR) kinase is activated by DNA replication stress and also by various forms of DNA damage, including DNA double-strand breaks (DSBs). Recruitment to sites of damage is insufficient for ATR activation as one of two known ATR activators, either topoisomerase II-binding protein (TOPBP1) or Ewing’s tumor-associated antigen 1, must also be present for signaling to initiate. Here, we employ our recently established DSB-mediated ATR activation in Xenopus egg extract (DMAX) system to examine how TOPBP1 is recruited to DSBs, so that it may activate ATR. We report that TOPBP1 is only transiently present at DSBs, with a half-life of less than 10 minutes. We also examined the relationship between TOPBP1 and the MRE11-RAD50-NBS1 (MRN), CtBP interacting protein (CtIP), and Ataxia Telangiectasia mutated (ATM) network of proteins. Loss of MRN prevents CtIP recruitment to DSBs, and partially inhibits TOPBP1 recruitment. Loss of CtIP has no impact on either MRN or TOPBP1 recruitment. Loss of ATM kinase activity prevents CtIP recruitment and enhances MRN and TOPBP1 recruitment. These findings demonstrate that there are MRN-dependent and independent pathways that recruit TOPBP1 to DSBs for ATR activation. Lastly, we find that both the 9-1-1 complex and MDC1 are dispensable for TOPBP1 recruitment to DSBs.
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Affiliation(s)
- Katrina Montales
- Department of Biological Sciences, Molecular and Computational Biology Section, University of Southern California, Los Angeles, California, United States of America
| | - Kenna Ruis
- Department of Biological Sciences, Molecular and Computational Biology Section, University of Southern California, Los Angeles, California, United States of America
| | - Howard Lindsay
- Faculty of Health and Medicine, Lancaster Medical School, Lancaster University, Lancaster, United Kingdom
| | - W. Matthew Michael
- Department of Biological Sciences, Molecular and Computational Biology Section, University of Southern California, Los Angeles, California, United States of America
- * E-mail:
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22
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Interaction with TopBP1 Is Required for Human Papillomavirus 16 E2 Plasmid Segregation/Retention Function during Mitosis. J Virol 2022; 96:e0083022. [PMID: 35880889 PMCID: PMC9400484 DOI: 10.1128/jvi.00830-22] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human papillomavirus 16 (HPV16) E2 is a DNA-binding protein that regulates transcription, replication and potentially, segregation of the HPV16 genome during the viral life cycle. In the segregation model, E2 simultaneously binds to viral and host chromatin, acting as a bridge to ensure that viral genomes reside in daughter nuclei following cell division. The host chromatin receptor for E2 mediating this function is unknown. Recently, we demonstrated that CK2 phosphorylation of E2 on serine 23 (S23) is required for interaction with TopBP1, and that this interaction promotes E2 and TopBP1 recruitment to mitotic chromatin. Here, we demonstrate that in U2OS cells expressing wild-type E2 and a non-TopBP1-binding mutant (S23A, serine 23 mutated to alanine), interaction with TopBP1 is essential for E2 recruitment of plasmids to mitotic chromatin. Using novel quantitative segregation assays, we demonstrate that interaction with TopBP1 is required for E2 plasmid segregation function in U2OS and N/Tert-1 cells. Small interfering RNA (siRNA) knockdown of TopBP1 or CK2 enzyme components disrupts E2 segregation/retention function. The interaction of E2 with TopBP1 promotes increased levels of E2 protein during mitosis in U2OS and N/Tert-1 cells, as well as in human foreskin keratinocytes (HFK) immortalized by the HPV16 genome. Overall, our results demonstrate that E2 has plasmid segregation activity, and that the E2-TopBP1 interaction is essential for this E2 function. IMPORTANCE HPV16 causes 3% to 4% of all human cancers. It is proposed that during the viral life cycle, the viral genome is actively segregated into daughter nuclei, ensuring viral replication in the subsequent S phase. The E2 protein potentially bridges the viral and host genomes during mitosis to mediate segregation of the circular viral plasmid. Here, we demonstrate that E2 has the ability to mediate plasmid segregation, and that this function is dependent upon interaction with the host protein TopBP1. Additionally, we demonstrate that the E2-TopBP1 interaction promotes enhanced E2 expression during mitosis, which likely promotes the plasmid segregation function of E2. Overall, our results present a mechanism of how HPV16 can segregate its viral genome during an active infection, a critical aspect of the viral life cycle.
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Lei T, Du S, Peng Z, Chen L. Multifaceted regulation and functions of 53BP1 in NHEJ‑mediated DSB repair (Review). Int J Mol Med 2022; 50:90. [PMID: 35583003 PMCID: PMC9162042 DOI: 10.3892/ijmm.2022.5145] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Accepted: 04/29/2022] [Indexed: 12/02/2022] Open
Abstract
The repair of DNA double-strand breaks (DSBs) is crucial for the preservation of genomic integrity and the maintenance of cellular homeostasis. Non-homologous DNA end joining (NHEJ) is the predominant repair mechanism for any type of DNA DSB during the majority of the cell cycle. NHEJ defects regulate tumor sensitivity to ionizing radiation and anti-neoplastic agents, resulting in immunodeficiencies and developmental abnormalities in malignant cells. p53-binding protein 1 (53BP1) is a key mediator involved in DSB repair, which functions to maintain a balance in the repair pathway choices and in preserving genomic stability. 53BP1 promotes DSB repair via NHEJ and antagonizes DNA end overhang resection. At present, novel lines of evidence have revealed the molecular mechanisms underlying the recruitment of 53BP1 and DNA break-responsive effectors to DSB sites, and the promotion of NHEJ-mediated DSB repair via 53BP1, while preventing homologous recombination. In the present review article, recent advances made in the elucidation of the structural and functional characteristics of 53BP1, the mechanisms of 53BP1 recruitment and interaction with the reshaping of the chromatin architecture around DSB sites, the post-transcriptional modifications of 53BP1, and the up- and downstream pathways of 53BP1 are discussed. The present review article also focuses on the application perspectives, current challenges and future directions of 53BP1 research.
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Affiliation(s)
- Tiantian Lei
- Department of Pharmacy, Women and Children's Hospital of Chongqing Medical University, Chongqing 401147, P.R. China
| | - Suya Du
- Department of Clinical Pharmacy, Sichuan Cancer Hospital and Institute, Sichuan Cancer Center, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan 610041, P.R. China
| | - Zhe Peng
- Department of Pharmacy, Women and Children's Hospital of Chongqing Medical University, Chongqing 401147, P.R. China
| | - Lin Chen
- Department of Pharmacy, Women and Children's Hospital of Chongqing Medical University, Chongqing 401147, P.R. China
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A PARylation-phosphorylation cascade promotes TOPBP1 loading and RPA-RAD51 exchange in homologous recombination. Mol Cell 2022; 82:2571-2587.e9. [PMID: 35597237 DOI: 10.1016/j.molcel.2022.04.031] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 02/14/2022] [Accepted: 04/22/2022] [Indexed: 01/30/2023]
Abstract
The efficiency of homologous recombination (HR) in the repair of DNA double-strand breaks (DSBs) is closely associated with genome stability and tumor response to chemotherapy. While many factors have been functionally characterized in HR, such as TOPBP1, their precise regulation remains unclear. Here, we report that TOPBP1 interacts with the RNA-binding protein HTATSF1 in a cell-cycle- and phosphorylation-dependent manner. Mechanistically, CK2 phosphorylates HTATSF1 to facilitate binding to TOPBP1, which promotes S-phase-specific TOPBP1 recruitment to damaged chromatin and subsequent RPA/RAD51-dependent HR, genome integrity, and cancer-cell viability. The localization of HTATSF1-TOPBP1 to DSBs is potentially independent of the transcription-coupled RNA-binding and processing capacity of HTATSF1 but rather relies on the recognition of poly(ADP-ribosyl)ated RPA by HTATSF1, which can be blunted with PARP inhibitors. Together, our study provides a mechanistic insight into TOPBP1 loading at HR-prone DSB sites via HTATSF1 and reveals how RPA-RAD51 exchange is tuned by a PARylation-phosphorylation cascade.
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Ruis K, Huynh O, Montales K, Barr NA, Michael WM. Delineation of a minimal topoisomerase II binding protein 1 (TOPBP1) for regulated activation of ATR at DNA double-strand breaks. J Biol Chem 2022; 298:101992. [PMID: 35490781 PMCID: PMC9257406 DOI: 10.1016/j.jbc.2022.101992] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 04/18/2022] [Accepted: 04/20/2022] [Indexed: 11/30/2022] Open
Abstract
Topoisomerase II Binding Protein 1 (TOPBP1) is an important activator of the DNA damage response kinase Ataxia Telangiectasia and Rad3-related (ATR), although the mechanism by which this activation occurs is not yet known. TOPBP1 contains nine copies of the BRCA1 C-terminal repeat (BRCT) motif, which allows protein–protein and protein–DNA interactions. TOPBP1 also contains an ATR activation domain (AAD), which physically interacts with ATR and its partner ATR-interacting protein (ATRIP) in a manner that stimulates ATR kinase activity. It is unclear which of TOPBP1’s nine BRCT domains participate in the reaction, as well as the individual roles played by these relevant BRCT domains. To address this knowledge gap, here, we delineated a minimal TOPBP1 that can activate ATR at DNA double-strand breaks in a regulated manner. We named this minimal TOPBP1 “Junior” and we show that Junior is composed of just three regions: BRCT0-2, the AAD, and BRCT7&8. We further defined the individual functions of these three regions by showing that BRCT0-2 is required for recruitment to DNA double-strand breaks and is dispensable thereafter, and that BRCT7&8 is dispensable for recruitment but essential to allow the AAD to multimerize and activate ATR. The delineation of TOPBP1 Junior creates a leaner, simplified, and better understood TOPBP1 and provides insight into the mechanism of ATR activation.
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Affiliation(s)
- Kenna Ruis
- Department of Biological Sciences, Molecular and Computational Biology Section, University of Southern California, Los Angeles, CA, 90089
| | - Oanh Huynh
- Department of Biological Sciences, Molecular and Computational Biology Section, University of Southern California, Los Angeles, CA, 90089
| | - Katrina Montales
- Department of Biological Sciences, Molecular and Computational Biology Section, University of Southern California, Los Angeles, CA, 90089
| | - Nina A Barr
- Department of Biological Sciences, Molecular and Computational Biology Section, University of Southern California, Los Angeles, CA, 90089
| | - W Matthew Michael
- Department of Biological Sciences, Molecular and Computational Biology Section, University of Southern California, Los Angeles, CA, 90089.
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Ma S, Zhang J, Guo Q, Cao C, Bao K, Liu L, Chen CD, Liu Z, Yang J, Yang N, Yao Z, Shi L. Disrupting PHF8-TOPBP1 connection elicits a breast tumor-specific vulnerability to chemotherapeutics. Cancer Lett 2022; 530:29-44. [PMID: 35051531 DOI: 10.1016/j.canlet.2022.01.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 12/27/2021] [Accepted: 01/10/2022] [Indexed: 12/14/2022]
Abstract
The DNA damage response (DDR) pathway generally protects against genome instability, and defects in DDR have been exploited therapeutically in cancer treatment. We have reported that histone demethylase PHF8 demethylates TOPBP1 K118 mono-methylation (K118me1) to drive the activation of ATR kinase, one of the master regulators of replication stress. However, whether dysregulation of this physiological signalling is involved in tumorigenesis remains unknown. Here, we showed PHF8-promoted TOPBP1 demethylation is clinically associated with breast tumorigenesis and patient survival. Mammary gland tumors from Phf8 knockout mice grow slowly and exhibit higher level of K118me1, lower ATR activity, and increased chromosomal instability. Importantly, we found that disruption of PHF8-TOPBP1 axis suppresses breast tumorigenesis and creates a breast tumor-specific vulnerability to PARP inhibitor (PARPi) and platinum drug. CRISPR/Cas9 mutation modelling of the deleted or truncated mutation of PHF8 in clinical tumor samples demonstrated breast tumor cells expressing the mimetic variants are more vulnerable to PARPi. Together, our study supports the pursuit of PHF8-TOPBP1 signalling pathway as promising avenues for targeted therapies of PHF8-TOPBP1 proficient tumors, and provides proof-of-concept evidence for loss-of-function of PHF8 as a therapeutic indicator of PARPis.
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Affiliation(s)
- Shuai Ma
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University General Hospital, Tianjin Medical University, Tianjin, 300070, China
| | - Jieyou Zhang
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University General Hospital, Tianjin Medical University, Tianjin, 300070, China
| | - Qiushi Guo
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University General Hospital, Tianjin Medical University, Tianjin, 300070, China
| | - Cheng Cao
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University General Hospital, Tianjin Medical University, Tianjin, 300070, China
| | - Kaiwen Bao
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University General Hospital, Tianjin Medical University, Tianjin, 300070, China
| | - Ling Liu
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University General Hospital, Tianjin Medical University, Tianjin, 300070, China
| | - Charlie Degui Chen
- State Key Laboratory of Molecular Biology, Shanghai Key Laboratory of Molecular Andrology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200031, China
| | - Zhe Liu
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University General Hospital, Tianjin Medical University, Tianjin, 300070, China
| | - Jie Yang
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University General Hospital, Tianjin Medical University, Tianjin, 300070, China
| | - Na Yang
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy and Key Laboratory of Medical Data Analysis and Statistical Research of Tianjin, Nankai University, 300353, Tianjin, China.
| | - Zhi Yao
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University General Hospital, Tianjin Medical University, Tianjin, 300070, China.
| | - Lei Shi
- State Key Laboratory of Experimental Hematology, The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University General Hospital, Tianjin Medical University, Tianjin, 300070, China.
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27
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TOPBP1 regulates resistance of gastric cancer to oxaliplatin by promoting transcription of PARP1. DNA Repair (Amst) 2022; 111:103278. [DOI: 10.1016/j.dnarep.2022.103278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 01/11/2022] [Accepted: 01/27/2022] [Indexed: 11/18/2022]
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28
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Tegowski M, Flamand MN, Meyer KD. scDART-seq reveals distinct m 6A signatures and mRNA methylation heterogeneity in single cells. Mol Cell 2022; 82:868-878.e10. [PMID: 35081365 PMCID: PMC8857065 DOI: 10.1016/j.molcel.2021.12.038] [Citation(s) in RCA: 75] [Impact Index Per Article: 37.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 12/22/2021] [Accepted: 12/23/2021] [Indexed: 12/14/2022]
Abstract
N6-methyladenosine (m6A) is an abundant RNA modification that plays critical roles in RNA regulation and cellular function. Global m6A profiling has revealed important aspects of m6A distribution and function, but to date such studies have been restricted to large populations of cells. Here, we develop a method to identify m6A sites transcriptome-wide in single cells. We uncover surprising heterogeneity in the presence and abundance of m6A sites across individual cells and identify differentially methylated mRNAs across the cell cycle. Additionally, we show that cellular subpopulations can be distinguished based on their RNA methylation signatures, independent from gene expression. These studies reveal fundamental features of m6A that have been missed by m6A profiling of bulk cells and suggest the presence of cell-intrinsic mechanisms for m6A deposition.
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Affiliation(s)
- Matthew Tegowski
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
| | - Mathieu N. Flamand
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
| | - Kate D. Meyer
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA,Department of Neurobiology, Duke University School of Medicine, Durham, NC 27710, USA,Lead contact,Correspondence:
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29
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Day M, Oliver AW, Pearl LH. Phosphorylation-dependent assembly of DNA damage response systems and the central roles of TOPBP1. DNA Repair (Amst) 2021; 108:103232. [PMID: 34678589 PMCID: PMC8651625 DOI: 10.1016/j.dnarep.2021.103232] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 09/23/2021] [Accepted: 09/24/2021] [Indexed: 11/11/2022]
Abstract
The cellular response to DNA damage (DDR) that causes replication collapse and/or DNA double strand breaks, is characterised by a massive change in the post-translational modifications (PTM) of hundreds of proteins involved in the detection and repair of DNA damage, and the communication of the state of damage to the cellular systems that regulate replication and cell division. A substantial proportion of these PTMs involve targeted phosphorylation, which among other effects, promotes the formation of multiprotein complexes through the specific binding of phosphorylated motifs on one protein, by specialised domains on other proteins. Understanding the nature of these phosphorylation mediated interactions allows definition of the pathways and networks that coordinate the DDR, and helps identify new targets for therapeutic intervention that may be of benefit in the treatment of cancer, where DDR plays a key role. In this review we summarise the present understanding of how phosphorylated motifs are recognised by BRCT domains, which occur in many DDR proteins. We particularly focus on TOPBP1 - a multi-BRCT domain scaffold protein with essential roles in replication and the repair and signalling of DNA damage.
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Affiliation(s)
- Matthew Day
- Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK
| | - Antony W Oliver
- Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK
| | - Laurence H Pearl
- Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK; Division of Structural Biology, Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London SW1E 6BT, UK.
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30
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Yoshida K, Fujita M. DNA damage responses that enhance resilience to replication stress. Cell Mol Life Sci 2021; 78:6763-6773. [PMID: 34463774 PMCID: PMC11072782 DOI: 10.1007/s00018-021-03926-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 08/16/2021] [Accepted: 08/24/2021] [Indexed: 12/12/2022]
Abstract
During duplication of the genome, eukaryotic cells may experience various exogenous and endogenous replication stresses that impede progression of DNA replication along chromosomes. Chemical alterations in template DNA, imbalances of deoxynucleotide pools, repetitive sequences, tight DNA-protein complexes, and conflict with transcription can negatively affect the replication machineries. If not properly resolved, stalled replication forks can cause chromosome breaks leading to genomic instability and tumor development. Replication stress is enhanced in cancer cells due, for example, to the loss of DNA repair genes or replication-transcription conflict caused by activation of oncogenic pathways. To prevent these serious consequences, cells are equipped with diverse mechanisms that enhance the resilience of replication machineries to replication stresses. This review describes DNA damage responses activated at stressed replication forks and summarizes current knowledge on the pathways that promote faithful chromosome replication and protect chromosome integrity, including ATR-dependent replication checkpoint signaling, DNA cross-link repair, and SLX4-mediated responses to tight DNA-protein complexes that act as barriers. This review also focuses on the relevance of replication stress responses to selective cancer chemotherapies.
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Affiliation(s)
- Kazumasa Yoshida
- Department of Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
- Department of Cell Biology, Faculty of Medicine, Fukuoka University, Fukuoka, 814-0180, Japan
- Central Research Institute for Advanced Molecular Medicine, Fukuoka University, Fukuoka, 814-0180, Japan
| | - Masatoshi Fujita
- Department of Cellular Biochemistry, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
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31
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Hussmann JA, Ling J, Ravisankar P, Yan J, Cirincione A, Xu A, Simpson D, Yang D, Bothmer A, Cotta-Ramusino C, Weissman JS, Adamson B. Mapping the genetic landscape of DNA double-strand break repair. Cell 2021; 184:5653-5669.e25. [PMID: 34672952 PMCID: PMC9074467 DOI: 10.1016/j.cell.2021.10.002] [Citation(s) in RCA: 81] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Revised: 08/31/2021] [Accepted: 09/29/2021] [Indexed: 12/20/2022]
Abstract
Cells repair DNA double-strand breaks (DSBs) through a complex set of pathways critical for maintaining genomic integrity. To systematically map these pathways, we developed a high-throughput screening approach called Repair-seq that measures the effects of thousands of genetic perturbations on mutations introduced at targeted DNA lesions. Using Repair-seq, we profiled DSB repair products induced by two programmable nucleases (Cas9 and Cas12a) in the presence or absence of oligonucleotides for homology-directed repair (HDR) after knockdown of 476 genes involved in DSB repair or associated processes. The resulting data enabled principled, data-driven inference of DSB end joining and HDR pathways. Systematic interrogation of this data uncovered unexpected relationships among DSB repair genes and demonstrated that repair outcomes with superficially similar sequence architectures can have markedly different genetic dependencies. This work provides a foundation for mapping DNA repair pathways and for optimizing genome editing across diverse modalities.
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Affiliation(s)
- Jeffrey A Hussmann
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA; Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94158, USA; Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94158, USA; Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Jia Ling
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Purnima Ravisankar
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Jun Yan
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Ann Cirincione
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Albert Xu
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA; Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Danny Simpson
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Dian Yang
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA; Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94158, USA; Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | | | | | - Jonathan S Weissman
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA; Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94158, USA; Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, Cambridge, MA 02142, USA; Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
| | - Britt Adamson
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA; Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.
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Prabhakar AT, James CD, Das D, Otoa R, Day M, Burgner J, Fontan CT, Wang X, Glass SH, Wieland A, Donaldson MM, Bristol ML, Li R, Oliver AW, Pearl LH, Smith BO, Morgan IM. CK2 Phosphorylation of Human Papillomavirus 16 E2 on Serine 23 Promotes Interaction with TopBP1 and Is Critical for E2 Interaction with Mitotic Chromatin and the Viral Life Cycle. mBio 2021; 12:e0116321. [PMID: 34544280 PMCID: PMC8546539 DOI: 10.1128/mbio.01163-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2021] [Accepted: 08/19/2021] [Indexed: 01/05/2023] Open
Abstract
During the human papillomavirus 16 (HPV16) life cycle, the E2 protein interacts with host factors to regulate viral transcription, replication, and genome segregation/retention. Our understanding of host partner proteins and their roles in E2 functions remains incomplete. Here we demonstrate that CK2 phosphorylation of E2 on serine 23 promotes interaction with TopBP1 in vitro and in vivo and that E2 is phosphorylated on this residue during the HPV16 life cycle. We investigated the consequences of mutating serine 23 on E2 functions. E2-S23A (E2 with serine 23 mutated to alanine) activates and represses transcription identically to E2-WT (wild-type E2), and E2-S23A is as efficient as E2-WT in transient replication assays. However, E2-S23A has compromised interaction with mitotic chromatin compared with E2-WT. In E2-WT cells, both E2 and TopBP1 levels increase during mitosis compared with vector control cells. In E2-S23A cells, neither E2 nor TopBP1 levels increase during mitosis. Introduction of the S23A mutation into the HPV16 genome resulted in delayed immortalization of human foreskin keratinocytes (HFK) and higher episomal viral genome copy number in resulting established HFK. Remarkably, S23A cells had a disrupted viral life cycle in organotypic raft cultures, with a loss of E2 expression and a failure of viral replication. Overall, our results demonstrate that CK2 phosphorylation of E2 on serine 23 promotes interaction with TopBP1 and that this interaction is critical for the viral life cycle. IMPORTANCE Human papillomaviruses are causative agents in around 5% of all cancers, with no specific antiviral therapeutics available for treating infections or resultant cancers. In this report, we demonstrate that phosphorylation of HPV16 E2 by CK2 promotes formation of a complex with the cellular protein TopBP1 in vitro and in vivo. This complex results in stabilization of E2 during mitosis. We demonstrate that CK2 phosphorylates E2 on serine 23 in vivo and that CK2 inhibitors disrupt the E2-TopBP1 complex. Mutation of E2 serine 23 to alanine disrupts the HPV16 life cycle, hindering immortalization and disrupting the viral life cycle, demonstrating a critical function for this residue.
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Affiliation(s)
- Apurva T. Prabhakar
- Virginia Commonwealth University (VCU), Philips Institute for Oral Health Research, School of Dentistry, Richmond, Virginia, USA
| | - Claire D. James
- Virginia Commonwealth University (VCU), Philips Institute for Oral Health Research, School of Dentistry, Richmond, Virginia, USA
| | - Dipon Das
- Virginia Commonwealth University (VCU), Philips Institute for Oral Health Research, School of Dentistry, Richmond, Virginia, USA
| | - Raymonde Otoa
- Virginia Commonwealth University (VCU), Philips Institute for Oral Health Research, School of Dentistry, Richmond, Virginia, USA
| | - Matthew Day
- Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - John Burgner
- Virginia Commonwealth University (VCU), Philips Institute for Oral Health Research, School of Dentistry, Richmond, Virginia, USA
| | - Christian T. Fontan
- Virginia Commonwealth University (VCU), Philips Institute for Oral Health Research, School of Dentistry, Richmond, Virginia, USA
| | - Xu Wang
- Virginia Commonwealth University (VCU), Philips Institute for Oral Health Research, School of Dentistry, Richmond, Virginia, USA
| | - Sarah H. Glass
- VCU School of Dentistry, Department of Oral Diagnostic Sciences, Richmond, Virginia, USA
| | - Andreas Wieland
- Emory Vaccine Center, Emory University School of Medicine, Atlanta, Georgia, USA
- Department of Microbiology & Immunology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Mary M. Donaldson
- School of Veterinary Medicine, University of Glasgow, Bearsden, United Kingdom
| | - Molly L. Bristol
- Virginia Commonwealth University (VCU), Philips Institute for Oral Health Research, School of Dentistry, Richmond, Virginia, USA
| | - Renfeng Li
- Virginia Commonwealth University (VCU), Philips Institute for Oral Health Research, School of Dentistry, Richmond, Virginia, USA
- VCU Massey Cancer Center, Richmond, Virginia, USA
| | - Anthony W. Oliver
- Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - Laurence H. Pearl
- Cancer Research UK DNA Repair Enzymes Group, Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - Brian O. Smith
- Institute of Molecular, Cell & Systems Biology, University of Glasgow, Glasgow, United Kingdom
| | - Iain M. Morgan
- Virginia Commonwealth University (VCU), Philips Institute for Oral Health Research, School of Dentistry, Richmond, Virginia, USA
- VCU Massey Cancer Center, Richmond, Virginia, USA
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33
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Toh M, Ngeow J. Homologous Recombination Deficiency: Cancer Predispositions and Treatment Implications. Oncologist 2021; 26:e1526-e1537. [PMID: 34021944 PMCID: PMC8417864 DOI: 10.1002/onco.13829] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 12/03/2020] [Indexed: 12/19/2022] Open
Abstract
Homologous recombination (HR) is a highly accurate DNA repair mechanism. Several HR genes are established cancer susceptibility genes with clinically actionable pathogenic variants (PVs). Classically, BRCA1 and BRCA2 germline PVs are associated with significant breast and ovarian cancer risks. Patients with BRCA1 or BRCA2 PVs display worse clinical outcomes but respond better to platinum-based chemotherapies and poly-ADP ribose polymerase inhibitors, a trait termed "BRCAness." With the advent of whole-exome sequencing and multigene panels, PVs in other HR genes are increasingly identified among familial cancers. As such, several genes such as PALB2 are reclassified as cancer predisposition genes. But evidence for cancer risks remains unclear for many others. In this review, we will discuss cancer predispositions and treatment implications beyond BRCA1 and BRCA2, with a focus on 24 HR genes: 53BP1, ATM, ATR, ATRIP, BARD1, BLM, BRIP1, DMC1, MRE11A, NBN, PALB2, RAD50, RAD51, RAD51B, RAD51C, RAD51D, RIF1, RMI1, RMI2, RPA1, TOP3A, TOPBP1, XRCC2, and XRCC3. IMPLICATIONS FOR PRACTICE: This review provides a comprehensive reference for readers to quickly identify potential cancer predisposing homologous recombination (HR) genes, and to generate research questions for genes with inconclusive evidence. This review also evaluates the "BRCAness" of each HR member. Clinicians can refer to these discussions to identify potential candidates for future clinical trials.
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Affiliation(s)
- MingRen Toh
- Duke–National University of Singapore Medical SchoolSingapore
| | - Joanne Ngeow
- Cancer Genetics Service, Division of Medical Oncology, National Cancer CenterSingapore
- Lee Kong Chian School of Medicine, Nanyang Technological UniversitySingapore
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34
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De Marco Zompit M, Stucki M. Mechanisms of genome stability maintenance during cell division. DNA Repair (Amst) 2021; 108:103215. [PMID: 34455186 DOI: 10.1016/j.dnarep.2021.103215] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 08/16/2021] [Accepted: 08/20/2021] [Indexed: 01/12/2023]
Abstract
During mitosis, chromosomes undergo extensive structural changes resulting in the formation of compact cylindrical bodies and in the termination of the bulk of DNA-dependent metabolic activities. Therefore, DNA lesions that interfere with processes such as DNA replication and transcription in interphase are not expected to pose a major threat to genome stability in mitosis. There are, however, a few exceptions. DNA replication and repair intermediates that physically interconnect the sister chromatids jeopardize faithful chromosome segregation and need to be resolved before the onset of anaphase. In addition, dicentric chromosomes can form chromatin bridges and induce breakage-fusion-breakage cycles with dire consequences for genome stability. Finally, chromosome breaks that escape the G2/M DNA damage checkpoint or emerge early in mitosis may result in lagging acentric DNA fragments that mis-segregate and form micronuclei when cells exit from mitosis. Both chromatin bridges and micronuclei are potential sources of a mutational cascade that results in massive chromosomal instability and significantly contributes to genomic complexity. Here, we review recent progress in our understanding of the origins and consequences of chromosome bridges and micronuclei and the mechanisms by which cells suppress them.
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Affiliation(s)
- Mara De Marco Zompit
- Department of Gynecology, University Hospital Zurich, University of Zurich, Wagistrasse 14, CH-8952 Schlieren, Switzerland
| | - Manuel Stucki
- Department of Gynecology, University Hospital Zurich, University of Zurich, Wagistrasse 14, CH-8952 Schlieren, Switzerland.
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35
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Velichko AK, Ovsyannikova N, Petrova NV, Luzhin AV, Vorobjeva M, Gavrikov AS, Mishin AS, Kireev II, Razin SV, Kantidze OL. Treacle and TOPBP1 control replication stress response in the nucleolus. J Cell Biol 2021; 220:212262. [PMID: 34100862 PMCID: PMC8190600 DOI: 10.1083/jcb.202008085] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Revised: 04/26/2021] [Accepted: 05/18/2021] [Indexed: 12/22/2022] Open
Abstract
Replication stress is one of the main sources of genome instability. Although the replication stress response in eukaryotic cells has been extensively studied, almost nothing is known about the replication stress response in nucleoli. Here, we demonstrate that initial replication stress-response factors, such as RPA, TOPBP1, and ATR, are recruited inside the nucleolus in response to drug-induced replication stress. The role of TOPBP1 goes beyond the typical replication stress response; it interacts with the low-complexity nucleolar protein Treacle (also referred to as TCOF1) and forms large Treacle-TOPBP1 foci inside the nucleolus. In response to replication stress, Treacle and TOPBP1 facilitate ATR signaling at stalled replication forks, reinforce ATR-mediated checkpoint activation inside the nucleolus, and promote the recruitment of downstream replication stress response proteins inside the nucleolus without forming nucleolar caps. Characterization of the Treacle-TOPBP1 interaction mode leads us to propose that these factors can form a molecular platform for efficient stress response in the nucleolus.
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Affiliation(s)
- Artem K Velichko
- Institute of Gene Biology Russian Academy of Sciences, Moscow, Russia.,Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology Russian Academy of Sciences, Moscow, Russia.,Institute for Translational Medicine and Biotechnology, Sechenov First Moscow State Medical University, Moscow, Russia
| | - Natalia Ovsyannikova
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | | | - Artem V Luzhin
- Institute of Gene Biology Russian Academy of Sciences, Moscow, Russia.,Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology Russian Academy of Sciences, Moscow, Russia
| | - Maria Vorobjeva
- Institute of Gene Biology Russian Academy of Sciences, Moscow, Russia
| | - Alexey S Gavrikov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry Russian Academy of Sciences, Moscow, Russia
| | - Alexander S Mishin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry Russian Academy of Sciences, Moscow, Russia
| | - Igor I Kireev
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia.,V.I. Kulakov National Medical Research Center for Obstetrics, Gynecology, and Perinatology, Moscow, Russia
| | - Sergey V Razin
- Institute of Gene Biology Russian Academy of Sciences, Moscow, Russia
| | - Omar L Kantidze
- Institute of Gene Biology Russian Academy of Sciences, Moscow, Russia
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36
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Ma S, Cao C, Che S, Wang Y, Su D, Liu S, Gong W, Liu L, Sun J, Zhao J, Wang Q, Song N, Ge T, Guo Q, Tian S, Chen CD, Zhang T, Wang J, Ding X, Yang F, Ying G, Yang J, Zhang K, Zhu Y, Yao Z, Yang N, Shi L. PHF8-promoted TOPBP1 demethylation drives ATR activation and preserves genome stability. SCIENCE ADVANCES 2021; 7:7/19/eabf7684. [PMID: 33952527 PMCID: PMC8099190 DOI: 10.1126/sciadv.abf7684] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 03/16/2021] [Indexed: 05/03/2023]
Abstract
The checkpoint kinase ATR [ATM (ataxia-telangiectasia mutated) and rad3-related] is a master regulator of DNA damage response. Yet, how ATR activity is regulated remains to be investigated. We report here that histone demethylase PHF8 (plant homeodomain finger protein 8) plays a key role in ATR activation and replication stress response. Mechanistically, PHF8 interacts with and demethylates TOPBP1 (DNA topoisomerase 2-binding protein 1), an essential allosteric activator of ATR, under unperturbed conditions, but replication stress results in PHF8 phosphorylation and dissociation from TOPBP1. Consequently, hypomethylated TOPBP1 facilitates RAD9 (RADiation sensitive 9) binding and chromatin loading of the TOPBP1-RAD9 complex to fully activate ATR and thus safeguard the genome and protect cells against replication stress. Our study uncovers a demethylation and phosphorylation code that controls the assembly of TOPBP1-scaffolded protein complex, and provides molecular insight into non-histone methylation switch in ATR activation.
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Affiliation(s)
- Shuai Ma
- State Key Laboratory of Experimental Hematology, 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University General Hospital, Tianjin Medical University, Tianjin 300070, China
| | - Cheng Cao
- State Key Laboratory of Experimental Hematology, 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University General Hospital, Tianjin Medical University, Tianjin 300070, China
| | - Shiyou Che
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy and Key Laboratory of Medical Data Analysis and Statistical Research of Tianjin, Nankai University, 300353 Tianjin, China
| | - Yuejiao Wang
- State Key Laboratory of Experimental Hematology, 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University General Hospital, Tianjin Medical University, Tianjin 300070, China
| | - Dongxue Su
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Shuai Liu
- State Key Laboratory of Experimental Hematology, 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University General Hospital, Tianjin Medical University, Tianjin 300070, China
| | - Wenchen Gong
- State Key Laboratory of Experimental Hematology, 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University General Hospital, Tianjin Medical University, Tianjin 300070, China
| | - Ling Liu
- State Key Laboratory of Experimental Hematology, 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University General Hospital, Tianjin Medical University, Tianjin 300070, China
| | - Jixue Sun
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy and Key Laboratory of Medical Data Analysis and Statistical Research of Tianjin, Nankai University, 300353 Tianjin, China
| | - Jiao Zhao
- State Key Laboratory of Experimental Hematology, 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University General Hospital, Tianjin Medical University, Tianjin 300070, China
| | - Qian Wang
- State Key Laboratory of Experimental Hematology, 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University General Hospital, Tianjin Medical University, Tianjin 300070, China
| | - Nan Song
- State Key Laboratory of Experimental Hematology, 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University General Hospital, Tianjin Medical University, Tianjin 300070, China
| | - Tong Ge
- State Key Laboratory of Experimental Hematology, 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University General Hospital, Tianjin Medical University, Tianjin 300070, China
| | - Qiushi Guo
- State Key Laboratory of Experimental Hematology, 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University General Hospital, Tianjin Medical University, Tianjin 300070, China
| | - Shanshan Tian
- State Key Laboratory of Experimental Hematology, 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University General Hospital, Tianjin Medical University, Tianjin 300070, China
| | - Charlie Degui Chen
- State Key Laboratory of Molecular Biology, Shanghai Key Laboratory of Molecular Andrology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Tao Zhang
- State Key Laboratory of Experimental Hematology, 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University General Hospital, Tianjin Medical University, Tianjin 300070, China
| | - Ju Wang
- State Key Laboratory of Experimental Hematology, 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University General Hospital, Tianjin Medical University, Tianjin 300070, China
| | - Xiang Ding
- Laboratory of Proteomics, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Fuquan Yang
- Laboratory of Proteomics, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Guoguang Ying
- State Key Laboratory of Experimental Hematology, 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University General Hospital, Tianjin Medical University, Tianjin 300070, China
| | - Jie Yang
- State Key Laboratory of Experimental Hematology, 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University General Hospital, Tianjin Medical University, Tianjin 300070, China
| | - Kai Zhang
- State Key Laboratory of Experimental Hematology, 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University General Hospital, Tianjin Medical University, Tianjin 300070, China
| | - Yi Zhu
- State Key Laboratory of Experimental Hematology, 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University General Hospital, Tianjin Medical University, Tianjin 300070, China
| | - Zhi Yao
- State Key Laboratory of Experimental Hematology, 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University General Hospital, Tianjin Medical University, Tianjin 300070, China.
| | - Na Yang
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy and Key Laboratory of Medical Data Analysis and Statistical Research of Tianjin, Nankai University, 300353 Tianjin, China.
| | - Lei Shi
- State Key Laboratory of Experimental Hematology, 2011 Collaborative Innovation Center of Tianjin for Medical Epigenetics, Key Laboratory of Breast Cancer Prevention and Therapy (Ministry of Education), Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University Cancer Institute and Hospital, Tianjin Medical University General Hospital, Tianjin Medical University, Tianjin 300070, China.
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37
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Sanford EJ, Comstock WJ, Faça VM, Vega SC, Gnügge R, Symington LS, Smolka MB. Phosphoproteomics reveals a distinctive Mec1/ATR signaling response upon DNA end hyper-resection. EMBO J 2021; 40:e104566. [PMID: 33764556 DOI: 10.15252/embj.2020104566] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 02/16/2021] [Accepted: 02/22/2021] [Indexed: 01/27/2023] Open
Abstract
The Mec1/ATR kinase is crucial for genome maintenance in response to a range of genotoxic insults, but it remains unclear how it promotes context-dependent signaling and DNA repair. Using phosphoproteomic analyses, we uncovered a distinctive Mec1/ATR signaling response triggered by extensive nucleolytic processing (resection) of DNA ends. Budding yeast cells lacking Rad9, a checkpoint adaptor and an inhibitor of resection, exhibit a selective increase in Mec1-dependent phosphorylation of proteins associated with single-strand DNA (ssDNA) transactions, including the ssDNA-binding protein Rfa2, the translocase/ubiquitin ligase Uls1, and the Sgs1-Top3-Rmi1 (STR) complex that regulates homologous recombination (HR). Extensive Mec1-dependent phosphorylation of the STR complex, mostly on the Sgs1 helicase subunit, promotes an interaction between STR and the DNA repair scaffolding protein Dpb11. Fusion of Sgs1 to phosphopeptide-binding domains of Dpb11 strongly impairs HR-mediated repair, supporting a model whereby Mec1 signaling regulates STR upon hyper-resection to influence recombination outcomes. Overall, the identification of a distinct Mec1 signaling response triggered by hyper-resection highlights the multi-faceted action of this kinase in the coordination of checkpoint signaling and HR-mediated DNA repair.
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Affiliation(s)
- Ethan J Sanford
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, USA
| | - William J Comstock
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, USA
| | - Vitor M Faça
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, USA.,Department of Biochemistry and Immunology and Cell-Based Therapy Center, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, Brazil
| | - Stephanie C Vega
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, USA
| | - Robert Gnügge
- Department of Microbiology and Immunology, Columbia University Irving Medical Center, New York, NY, USA
| | - Lorraine S Symington
- Department of Microbiology and Immunology, Columbia University Irving Medical Center, New York, NY, USA
| | - Marcus B Smolka
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, USA
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38
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Liu K, Graves JD, Lin FT, Lin WC. Overexpression of TopBP1, a canonical ATR/Chk1 activator, paradoxically hinders ATR/Chk1 activation in cancer. J Biol Chem 2021; 296:100382. [PMID: 33556369 PMCID: PMC7949146 DOI: 10.1016/j.jbc.2021.100382] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 01/26/2021] [Accepted: 02/02/2021] [Indexed: 11/05/2022] Open
Abstract
Topoisomerase IIβ-binding protein 1 (TopBP1) is involved in cellular replication among other functions and is known to activate ATR/Chk1 during replicative stress. TopBP1 is also expressed at high levels in many cancers. However, the impact of TopBP1 overexpression on ATR/Chk1 activation and cancer development has not been investigated. Here we demonstrate that the degree of ATR/Chk1 activation is regulated by TopBP1 in a biphasic, concentration-dependent manner in a nontransformed MCF10A cell line and several cancer cell lines, including H1299, MDA-MB468, and U2OS. At low levels, TopBP1 activates ATR/Chk1, but once TopBP1 protein accumulates above an optimal level, it paradoxically leads to lower activation of ATR/Chk1. This is due to the perturbation of ATR–TopBP1 interaction and ATR chromatin loading by excessive TopBP1. Overexpression of TopBP1 thus hinders the ATR/Chk1 checkpoint response, leading to the impairment of genome integrity as demonstrated by the cytokinesis-block micronucleus assay. In contrast, moderate depletion of TopBP1 by shRNA in TopBP1-overexpressing cancer cells enhanced ATR/Chk1 activation and S-phase checkpoint response after replicative stress. The clinical significance of these findings is supported by an association between TopBP1 overexpression and genome instability in many types of human cancer. Taken together, our study illustrates an unexpected relationship between the levels of TopBP1 and the final functional outcome and suggests TopBP1 overexpression as a new mechanism directly contributing to genomic instability during tumorigenesis.
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Affiliation(s)
- Kang Liu
- Section of Hematology/Oncology, Department of Medicine, Baylor College of Medicine, Houston, Texas, USA
| | - Joshua D Graves
- Section of Hematology/Oncology, Department of Medicine, Baylor College of Medicine, Houston, Texas, USA
| | - Fang-Tsyr Lin
- Section of Hematology/Oncology, Department of Medicine, Baylor College of Medicine, Houston, Texas, USA
| | - Weei-Chin Lin
- Section of Hematology/Oncology, Department of Medicine, Baylor College of Medicine, Houston, Texas, USA; Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA.
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39
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Structure-function analysis of TOPBP1's role in ATR signaling using the DSB-mediated ATR activation in Xenopus egg extracts (DMAX) system. Sci Rep 2021; 11:467. [PMID: 33432091 PMCID: PMC7801695 DOI: 10.1038/s41598-020-80626-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 12/23/2020] [Indexed: 11/20/2022] Open
Abstract
The protein kinase ATR is activated at sites of DNA double-strand breaks where it plays important roles in promoting DNA end resection and regulating cell cycle progression. TOPBP1 is a multi BRCT repeat containing protein that activates ATR at DSBs. Here we have developed an experimental tool, the DMAX system, to study the biochemical mechanism for TOPBP1-mediated ATR signalling. DMAX combines simple, linear dsDNA molecules with Xenopus egg extracts and results in a physiologically relevant, DSB-induced activation of ATR. We find that DNAs of 5000 nucleotides, at femtomolar concentration, potently activate ATR in this system. By combining immunodepletion and add-back of TOPBP1 point mutants we use DMAX to determine which of TOPBP1’s nine BRCT domains are required for recruitment of TOPBP1 to DSBs and which domains are needed for ATR-mediated phosphorylation of CHK1. We find that BRCT1 and BRCT7 are important for recruitment and that BRCT5 functions downstream of recruitment to promote ATR-mediated phosphorylation of CHK1. We also show that BRCT7 plays a second role, independent of recruitment, in promoting ATR signalling. These findings supply a new research tool for, and new insights into, ATR biology.
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40
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Ackerson SM, Gable CI, Stewart JA. Human CTC1 promotes TopBP1 stability and CHK1 phosphorylation in response to telomere dysfunction and global replication stress. Cell Cycle 2020; 19:3491-3507. [PMID: 33269665 PMCID: PMC7781613 DOI: 10.1080/15384101.2020.1849979] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 10/30/2020] [Accepted: 11/07/2020] [Indexed: 01/21/2023] Open
Abstract
CST (CTC1-STN1-TEN1) is a heterotrimeric, RPA-like complex that binds to single-stranded DNA (ssDNA) and functions in the replication of telomeric and non-telomeric DNA. Previous studies demonstrated that deletion of CTC1 results in decreased cell proliferation and telomere DNA damage signaling. However, a detailed analysis of the consequences of conditional CTC1 knockout (KO) has not been fully elucidated. Here, we investigated the effects of CTC1 KO on cell cycle progression, genome-wide replication and activation of the DNA damage response. Consistent with previous findings, we demonstrate that CTC1 KO results in decreased cell proliferation, G2 arrest and RPA-bound telomeric ssDNA. However, despite the increased levels of telomeric RPA-ssDNA, global ATR-dependent CHK1 and p53 phosphorylation was not detected in CTC1 KO cells. Nevertheless, we show that RPA-ssDNA does activate ATR, leading to the phosphorylation of RPA and autophosphorylation of ATR. Further analysis determined that inactivation of ATR, but not CHK1 or ATM, suppressed the accumulation of G2 arrested cells and phosphorylated RPA following CTC1 removal. These results suggest that ATR is localized and active at telomeres but is unable to elicit a global checkpoint response through CHK1. Furthermore, CTC1 KO inhibited CHK1 phosphorylation following hydroxyurea-induced replication stress. Additional studies revealed that this suppression of CHK1 phosphorylation, following replication stress, is caused by decreased levels of the ATR activator TopBP1. Overall, our results identify CST as a novel regulator of the ATR-CHK1 pathway.
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Affiliation(s)
| | - Caroline I. Gable
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
| | - Jason A. Stewart
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
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41
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Feng H, Lu J, Song X, Thongkum A, Zhang F, Lou L, Reizes O, Almasan A, Gong Z. CK2 kinase-mediated PHF8 phosphorylation controls TopBP1 stability to regulate DNA replication. Nucleic Acids Res 2020; 48:10940-10952. [PMID: 33010150 PMCID: PMC7641741 DOI: 10.1093/nar/gkaa756] [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: 02/10/2020] [Revised: 08/31/2020] [Accepted: 09/03/2020] [Indexed: 11/12/2022] Open
Abstract
ATR functions as a master regulator of the DNA-damage response. ATR activation requires the ATR activator, topoisomerase IIβ-binding protein 1 (TopBP1). However, the underlying mechanism of TopBP1 regulation and how its regulation affects DNA replication remain unknown. Here, we report a specific interaction between TopBP1 and the histone demethylase PHF8. The TopBP1/PHF8 interaction is mediated by the BRCT 7+8 domain of TopBP1 and phosphorylation of PHF8 at Ser854. This interaction is cell-cycle regulated and phosphorylation-dependent. PHF8 is phosphorylated by CK2, which regulates binding of PHF8 to TopBP1. Importantly, PHF8 regulates TopBP1 protein level by preventing its ubiquitination and degradation mediated by the E3 ligase UBR5. Interestingly, PHF8pS854 is likely to contribute to regulation of TopBP1 stability and DNA replication checkpoint. Further, both TopBP1 and PHF8 are required for efficient replication fork restart. Together, these data identify PHF8 as a TopBP1-binding protein and provide mechanistic insight into how PHF8 regulates TopBP1 stability to maintain DNA replication.
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Affiliation(s)
- Haihua Feng
- Department of Cancer Biology, Cleveland Clinic Lerner Research Institute, Cleveland, OH 44195, USA
| | - Jingchen Lu
- Department of Cancer Biology, Cleveland Clinic Lerner Research Institute, Cleveland, OH 44195, USA.,Department of Medical Oncology, Xiangya Hospital, Central South University, Changsha, China
| | - Xiaotian Song
- Department of Cancer Biology, Cleveland Clinic Lerner Research Institute, Cleveland, OH 44195, USA
| | - Angkana Thongkum
- Department of Cancer Biology, Cleveland Clinic Lerner Research Institute, Cleveland, OH 44195, USA
| | - Fan Zhang
- Department of Cancer Biology, Cleveland Clinic Lerner Research Institute, Cleveland, OH 44195, USA
| | - Lihong Lou
- Department of Cancer Biology, Cleveland Clinic Lerner Research Institute, Cleveland, OH 44195, USA
| | - Ofer Reizes
- Department of Cardiovascular & Metabolic Sciences, Cleveland Clinic Lerner Research Institute, Cleveland, OH 44195, USA
| | - Alexandru Almasan
- Department of Cancer Biology, Cleveland Clinic Lerner Research Institute, Cleveland, OH 44195, USA
| | - Zihua Gong
- Department of Cancer Biology, Cleveland Clinic Lerner Research Institute, Cleveland, OH 44195, USA.,Case Comprehensive Cancer Center, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
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42
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Das D, Bristol ML, Pichierri P, Morgan IM. Using a Human Papillomavirus Model to Study DNA Replication and Repair of Wild Type and Damaged DNA Templates in Mammalian Cells. Int J Mol Sci 2020; 21:E7564. [PMID: 33066318 PMCID: PMC7589113 DOI: 10.3390/ijms21207564] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 10/06/2020] [Accepted: 10/12/2020] [Indexed: 12/13/2022] Open
Abstract
Human papillomaviruses have 8kbp DNA episomal genomes that replicate autonomously from host DNA. During initial infection, the virus increases its copy number to 20-50 copies per cell, causing torsional stress on the replicating DNA. This activates the DNA damage response (DDR) and HPV replicates its genome, at least in part, using homologous recombination. An active DDR is on throughout the HPV life cycle. Two viral proteins are required for replication of the viral genome; E2 binds to 12bp palindromic sequences around the A/T rich origin of replication and recruits the viral helicase E1 via a protein-protein interaction. E1 forms a di-hexameric complex that replicates the viral genome in association with host factors. Transient replication assays following transfection with E1-E2 expression plasmids, along with an origin containing plasmid, allow monitoring of E1-E2 replication activity. Incorporating a bacterial lacZ gene into the origin plasmid allows for the determination of replication fidelity. Here we describe how we exploited this system to investigate replication and repair in mammalian cells, including using damaged DNA templates. We propose that this system has the potential to enhance the understanding of cellular components involved in DNA replication and repair.
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Affiliation(s)
- Dipon Das
- Department of Oral and Craniofacial Molecular Biology, VCU Philips Institute for Oral Health Research, Virginia Commonwealth University School of Dentistry, Richmond, VA 23298, USA; (D.D.); (M.L.B.)
| | - Molly L. Bristol
- Department of Oral and Craniofacial Molecular Biology, VCU Philips Institute for Oral Health Research, Virginia Commonwealth University School of Dentistry, Richmond, VA 23298, USA; (D.D.); (M.L.B.)
| | - Pietro Pichierri
- Department of Environment and Health, Istituto Superiore di Sanita’, 00161 Rome, Italy;
| | - Iain M. Morgan
- Department of Oral and Craniofacial Molecular Biology, VCU Philips Institute for Oral Health Research, Virginia Commonwealth University School of Dentistry, Richmond, VA 23298, USA; (D.D.); (M.L.B.)
- VCU Massey Cancer Center, Richmond, VA 23298, USA
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43
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Biochemical analysis of TOPBP1 oligomerization. DNA Repair (Amst) 2020; 96:102973. [PMID: 32987353 DOI: 10.1016/j.dnarep.2020.102973] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 08/20/2020] [Accepted: 09/09/2020] [Indexed: 11/24/2022]
Abstract
TOPBP1 is an important scaffold protein that helps orchestrate the cellular response to DNA damage. Although it has been previously appreciated that TOPBP1 can form oligomers, how this occurs and the functional consequences for oligomerization were not yet known. Here, we use protein binding assays and other biochemical techniques to study how TOPBP1 self associates. TOPBP1 contains 9 copies of the BRCT domain, and we report that a subset of these BRCT domains interact with one another to drive oligomerization. An intact BRCT 2 domain is required for TOPBP1 oligomerization and we find that the BRCT1&2 region of TOPBP1 interacts with itself and with the BRCT4&5 pair. RAD9 and RHINO are two heterologous binding partners for TOPBP1's BRCT 1&2 domains, and we show that binding of these partners does not come at the expense of TOPBP1 oligomerization. Furthermore, we show that a TOPBP1 oligomer can simultaneously interact with both RAD9 and RHINO. Lastly, we find that the oligomeric state necessary for TOPBP1 to activate the ATR protein kinase is likely to be a tetramer.
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44
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Zhou Y, Chen R, Luo X, Zhang WD, Qin JJ. The E2 ubiquitin-conjugating enzyme UbcH5c: an emerging target in cancer and immune disorders. Drug Discov Today 2020; 25:S1359-6446(20)30369-X. [PMID: 32947046 DOI: 10.1016/j.drudis.2020.09.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 07/14/2020] [Accepted: 09/10/2020] [Indexed: 02/06/2023]
Abstract
Ubiquitination is a crucial post-translational modification (PTM) of proteins and regulates their stabilities and activities, thereby modulating multiple signaling pathways. UbcH5c, a member of the UbcH5 ubiquitin-conjugating enzyme (E2) protein family, engages in the ubiquitination of dozens of proteins and regulates nuclear factor kappa-B (NF-κB), p53 tumor suppressor, and several other essential signaling pathways. UbcH5c has been reported to be abnormally expressed in human cancer and immune disorders and is involved in the initiation and progression of these diseases. In this review, we mainly focus on UbcH5c structure, activity, signaling pathways, and its relevance to cancer and immune disorders. We end by integrating all known factors relating to UbcH5c inhibition as a potential cancer therapy method, and discuss associated challenges.
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Affiliation(s)
- Yuan Zhou
- College of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou 310053, China
| | - Runzhe Chen
- Department of Thoracic/Head and Neck Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Xiaofang Luo
- College of Chemistry and Bioengineering, Hunan University of Science and Engineering, Yongzhou 425199, China
| | - Wei-Dong Zhang
- School of Pharmacy, Naval Medical University, Shanghai 200433, China.
| | - Jiang-Jiang Qin
- College of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou 310053, China; Institute of Cancer and Basic Medicine, Chinese Academy of Sciences; Cancer Hospital of the University of Chinese Academy of Sciences; Zhejiang Cancer Hospital, Hangzhou 310022, China.
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45
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Kleinberger T. En Guard! The Interactions between Adenoviruses and the DNA Damage Response. Viruses 2020; 12:v12090996. [PMID: 32906746 PMCID: PMC7552057 DOI: 10.3390/v12090996] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 09/01/2020] [Accepted: 09/01/2020] [Indexed: 02/07/2023] Open
Abstract
Virus–host cell interactions include several skirmishes between the virus and its host, and the DNA damage response (DDR) network is one of their important battlegrounds. Although some aspects of the DDR are exploited by adenovirus (Ad) to improve virus replication, especially at the early phase of infection, a large body of evidence demonstrates that Ad devotes many of its proteins, including E1B-55K, E4orf3, E4orf4, E4orf6, and core protein VII, and utilizes varied mechanisms to inhibit the DDR. These findings indicate that the DDR would strongly restrict Ad replication if allowed to function efficiently. Various Ad serotypes inactivate DNA damage sensors, including the Mre11-Rad50-Nbs1 (MRN) complex, DNA-dependent protein kinase (DNA-PK), and Poly (ADP-ribose) polymerase 1 (PARP-1). As a result, these viruses inhibit signaling via DDR transducers, such as the ataxia-telangiectasia mutated (ATM) and ATM- and Rad3-related (ATR) kinases, to downstream effectors. The different Ad serotypes utilize both shared and distinct mechanisms to inhibit various branches of the DDR. The aim of this review is to understand the interactions between Ad proteins and the DDR and to appreciate how these interactions contribute to viral replication.
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Affiliation(s)
- Tamar Kleinberger
- Department of Molecular Microbiology, Faculty of Medicine, Technion-Israel Institute of Technology, 1 Efron St., Bat Galim, Haifa 31096, Israel
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46
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Manickavinayaham S, Velez-Cruz R, Biswas AK, Chen J, Guo R, Johnson DG. The E2F1 transcription factor and RB tumor suppressor moonlight as DNA repair factors. Cell Cycle 2020; 19:2260-2269. [PMID: 32787501 PMCID: PMC7513849 DOI: 10.1080/15384101.2020.1801190] [Citation(s) in RCA: 17] [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: 05/26/2020] [Revised: 06/19/2020] [Accepted: 07/06/2020] [Indexed: 02/08/2023] Open
Abstract
The E2F1 transcription factor and RB tumor suppressor are best known for their roles in regulating the expression of genes important for cell cycle progression but, they also have transcription-independent functions that facilitate DNA repair at sites of damage. Depending on the type of DNA damage, E2F1 can recruit either the GCN5 or p300/CBP histone acetyltransferases to deposit different histone acetylation marks in flanking chromatin. At DNA double-strand breaks, E2F1 also recruits RB and the BRG1 ATPase to remodel chromatin and promote loading of the MRE11-RAD50-NBS1 complex. Knock-in mouse models demonstrate important roles for E2F1 post-translational modifications in regulating DNA repair and physiological responses to DNA damage. This review highlights how E2F1 moonlights in DNA repair, thus revealing E2F1 as a versatile protein that recruits many of the same chromatin-modifying enzymes to sites of DNA damage to promote repair that it recruits to gene promoters to regulate transcription.
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Affiliation(s)
- Swarnalatha Manickavinayaham
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX, USA
| | - Renier Velez-Cruz
- Department of Biochemistry and Molecular Genetics, College of Graduate Studies, Midwestern University, Downers Grove, IL, USA
| | - Anup K. Biswas
- Herbert Irving Comprehensive Cancer Center, Columbia University, New York, NY, USA
| | - Jie Chen
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX, USA
| | - Ruifeng Guo
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - David G. Johnson
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX, USA
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47
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Li K, Peng S, Li Z, Lai Y, Wang Q, Tao Y, Wu W, Zhou Q, Gao Z, Chen J, Li H, Cai W, Guo Z, Huang H. Topoisomerase II-binding protein 1 promotes the progression of prostate cancer via ATR-CHK1 signaling pathway. Aging (Albany NY) 2020; 12:9948-9958. [PMID: 32459662 PMCID: PMC7288942 DOI: 10.18632/aging.103260] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 04/18/2020] [Indexed: 12/24/2022]
Abstract
DNA damage response (DDR) plays an important role in the progression of cancers, including prostate cancer (PCa). Topoisomerase II-binding protein 1 (TopBP1) is an essential promotor of ATR-mediated DDR. Herein, we investigated the association between TopBP1 and PCa and determined its effect on the progression of PCa. The expression and clinical features of TopBP1 were analyzed using large-scale cohort of tissue microarray analyses and The Cancer Genome Atlas database, which indicated that TopBP1 was positively correlated with high Gleason Score, advanced clinical and pathological stages, the metastasis status. Multivariate analysis revealed that the upregulation of TopBP1 was an independent predictor for a worse biochemical recurrence-free survival (BCR-free survival). Furthermore, we discovered that downregulation of TopBP1 significantly suppressed the growth and migration ability of PCa lines by loss-of-function assays in vitro. Further mechanistic investigations clarified that TopBP1 promoted proliferation and migration by activating ATR-Chk1 signaling pathway.
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Affiliation(s)
- Kaiwen Li
- Department of Urology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Shirong Peng
- Department of Urology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Zean Li
- Department of Urology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Yiming Lai
- Department of Urology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Qiong Wang
- Department of Urology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Yiran Tao
- Department of Urology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Wanhua Wu
- Department of Urology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Qianghua Zhou
- Department of Urology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Ze Gao
- Department of Urology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Junxiu Chen
- Department of Urology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Hui Li
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22903, USA
| | - Wenli Cai
- Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Zhenghui Guo
- Department of Urology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Hai Huang
- Department of Urology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
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48
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Blackford AN, Stucki M. How Cells Respond to DNA Breaks in Mitosis. Trends Biochem Sci 2020; 45:321-331. [PMID: 32001093 DOI: 10.1016/j.tibs.2019.12.010] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 12/05/2019] [Accepted: 12/31/2019] [Indexed: 12/16/2022]
Abstract
DNA double-strand breaks (DSBs) are highly toxic lesions that can lead to chromosomal instability if they are not repaired correctly. DSBs are especially dangerous in mitosis when cells go through the complex process of equal chromosome segregation into daughter cells. When cells encounter DSBs in interphase, they are able to arrest the cell cycle until the breaks are repaired before entering mitosis. However, when DSBs occur during mitosis, cells no longer arrest but prioritize completion of cell division over repair of DNA damage. This review focuses on recent progress in our understanding of the mechanisms that allow mitotic cells to postpone DSB repair without accumulating massive chromosomal instability. Additionally, we review possible physiological consequences of failed DSB responses in mitosis.
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Affiliation(s)
- Andrew N Blackford
- Department of Oncology, MRC Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK; Cancer Research UK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford OX3 7DQ, UK.
| | - Manuel Stucki
- Department of Gynecology, University of Zurich, Wagistrasse 14, CH-8952 Schlieren, Switzerland.
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49
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Cell Cycle-Dependent Switch of TopBP1 Functions by Cdk2 and Akt. Mol Cell Biol 2020; 40:MCB.00599-19. [PMID: 31964753 DOI: 10.1128/mcb.00599-19] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 01/07/2020] [Indexed: 01/25/2023] Open
Abstract
Cdk2-dependent TopBP1-treslin interaction is critical for DNA replication initiation. However, it remains unclear how this association is terminated after replication initiation is finished. Here, we demonstrate that phosphorylation of TopBP1 by Akt coincides with cyclin A activation during S and G2 phases and switches the TopBP1-interacting partner from treslin to E2F1, which results in the termination of replication initiation. Premature activation of Akt in G1 phase causes an early switch and inhibits DNA replication. TopBP1 is often overexpressed in cancer and can bypass control by Cdk2 to interact with treslin, leading to enhanced DNA replication. Consistent with this notion, reducing the levels of TopBP1 in cancer cells restores sensitivity to a Cdk2 inhibitor. Together, our study links Cdk2 and Akt pathways to the control of DNA replication through the regulation of TopBP1-treslin interaction. These data also suggest an important role for TopBP1 in driving abnormal DNA replication in cancer.
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50
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Baudier J, Deloulme JC, Shaw GS. The Zn 2+ and Ca 2+ -binding S100B and S100A1 proteins: beyond the myths. Biol Rev Camb Philos Soc 2020; 95:738-758. [PMID: 32027773 DOI: 10.1111/brv.12585] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 01/06/2020] [Accepted: 01/20/2020] [Indexed: 12/17/2022]
Abstract
The S100 genes encode a conserved group of 21 vertebrate-specific EF-hand calcium-binding proteins. Since their discovery in 1965, S100 proteins have remained enigmatic in terms of their cellular functions. In this review, we summarize the calcium- and zinc-binding properties of the dimeric S100B and S100A1 proteins and highlight data that shed new light on the extracellular and intracellular regulation and functions of S100B. We point out that S100B and S100A1 homodimers are not functionally interchangeable and that in a S100A1/S100B heterodimer, S100A1 acts as a negative regulator for the ability of S100B to bind Zn2+ . The Ca2+ and Zn2+ -dependent interactions of S100B with a wide array of proteins form the basis of its activities and have led to the derivation of some initial rules for S100B recognition of protein targets. However, recent findings have strongly suggested that these rules need to be revisited. Here, we describe a new consensus S100B binding motif present in intracellular and extracellular vertebrate-specific proteins and propose a new model for stable interactions of S100B dimers with full-length target proteins. A chaperone-associated function for intracellular S100B in adaptive cellular stress responses is also discussed. This review may help guide future studies on the functions of S100 proteins in general.
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Affiliation(s)
- Jacques Baudier
- Institut de Biologie du Développement de Marseille-UMR CNRS 7288, Aix Marseille Université, 13288, Marseille Cedex 9, France
| | - Jean Christophe Deloulme
- Grenoble Institut des Neurosciences, INSERM U1216, Université Grenoble Alpes, 38000, Grenoble, France
| | - Gary S Shaw
- Department of Biochemistry, University of Western Ontario, London, Ontario, N6A5C1, Canada
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