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Wu J, Song L, Lu M, Gao Q, Xu S, Zhou P, Ma T. The multifaceted functions of DNA-PKcs: implications for the therapy of human diseases. MedComm (Beijing) 2024; 5:e613. [PMID: 38898995 PMCID: PMC11185949 DOI: 10.1002/mco2.613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 05/07/2024] [Accepted: 05/09/2024] [Indexed: 06/21/2024] Open
Abstract
The DNA-dependent protein kinase (DNA-PK), catalytic subunit, also known as DNA-PKcs, is complexed with the heterodimer Ku70/Ku80 to form DNA-PK holoenzyme, which is well recognized as initiator in the nonhomologous end joining (NHEJ) repair after double strand break (DSB). During NHEJ, DNA-PKcs is essential for both DNA end processing and end joining. Besides its classical function in DSB repair, DNA-PKcs also shows multifaceted functions in various biological activities such as class switch recombination (CSR) and variable (V) diversity (D) joining (J) recombination in B/T lymphocytes development, innate immunity through cGAS-STING pathway, transcription, alternative splicing, and so on, which are dependent on its function in NHEJ or not. Moreover, DNA-PKcs deficiency has been proven to be related with human diseases such as neurological pathogenesis, cancer, immunological disorder, and so on through different mechanisms. Therefore, it is imperative to summarize the latest findings about DNA-PKcs and diseases for better targeting DNA-PKcs, which have shown efficacy in cancer treatment in preclinical models. Here, we discuss the multifaceted roles of DNA-PKcs in human diseases, meanwhile, we discuss the progresses of DNA-PKcs inhibitors and their potential in clinical trials. The most updated review about DNA-PKcs will hopefully provide insights and ideas to understand DNA-PKcs associated diseases.
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Affiliation(s)
- Jinghong Wu
- Cancer Research CenterBeijing Chest HospitalCapital Medical University/Beijing Tuberculosis and Thoracic Tumor Research InstituteBeijingChina
| | - Liwei Song
- Department of Thoracic SurgeryBeijing Chest HospitalCapital Medical University, Beijing Tuberculosis and Thoracic Tumor Research InstituteBeijingChina
| | - Mingjun Lu
- Cancer Research CenterBeijing Chest HospitalCapital Medical University/Beijing Tuberculosis and Thoracic Tumor Research InstituteBeijingChina
| | - Qing Gao
- Cancer Research CenterBeijing Chest HospitalCapital Medical University/Beijing Tuberculosis and Thoracic Tumor Research InstituteBeijingChina
| | - Shaofa Xu
- Department of Thoracic SurgeryBeijing Chest HospitalCapital Medical University, Beijing Tuberculosis and Thoracic Tumor Research InstituteBeijingChina
| | - Ping‐Kun Zhou
- Beijing Key Laboratory for RadiobiologyBeijing Institute of Radiation MedicineBeijingChina
| | - Teng Ma
- Cancer Research CenterBeijing Chest HospitalCapital Medical University/Beijing Tuberculosis and Thoracic Tumor Research InstituteBeijingChina
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2
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Han Y, Zhao H, Li G, Jia J, Guo H, Tan J, Sun X, Li S, Ran Q, Bai C, Gu Y, Li Z, Guan H, Gao S, Zhou PK. GCN5 mediates DNA-PKcs crotonylation for DNA double-strand break repair and determining cancer radiosensitivity. Br J Cancer 2024; 130:1621-1634. [PMID: 38575732 PMCID: PMC11091118 DOI: 10.1038/s41416-024-02636-4] [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: 12/12/2023] [Revised: 02/18/2024] [Accepted: 02/21/2024] [Indexed: 04/06/2024] Open
Abstract
BACKGROUND DNA double-strand break (DSB) induction and repair are important events for determining cell survival and the outcome of cancer radiotherapy. The DNA-dependent protein kinase (DNA-PK) complex functions at the apex of DSBs repair, and its assembly and activity are strictly regulated by post-translation modifications (PTMs)-associated interactions. However, the PTMs of the catalytic subunit DNA-PKcs and how they affect DNA-PKcs's functions are not fully understood. METHODS Mass spectrometry analyses were performed to identify the crotonylation sites of DNA-PKcs in response to γ-ray irradiation. Co-immunoprecipitation (Co-IP), western blotting, in vitro crotonylation assays, laser microirradiation assays, in vitro DNA binding assays, in vitro DNA-PK assembly assays and IF assays were employed to confirm the crotonylation, identify the crotonylase and decrotonylase, and elucidate how crotonylation regulates the activity and function of DNA-PKcs. Subcutaneous xenografts of human HeLa GCN5 WT or HeLa GCN5 siRNA cells in BALB/c nude mice were generated and utilized to assess tumor proliferation in vivo after radiotherapy. RESULTS Here, we reveal that K525 is an important site of DNA-PKcs for crotonylation, and whose level is sharply increased by irradiation. The histone acetyltransferase GCN5 functions as the crotonylase for K525-Kcr, while HDAC3 serves as its dedicated decrotonylase. K525 crotonylation enhances DNA binding activity of DNA-PKcs, and facilitates assembly of the DNA-PK complex. Furthermore, GCN5-mediated K525 crotonylation is indispensable for DNA-PKcs autophosphorylation and the repair of double-strand breaks in the NHEJ pathway. GCN5 suppression significantly sensitizes xenograft tumors of mice to radiotherapy. CONCLUSIONS Our study defines K525 crotonylation of DNA-PKcs is important for the DNA-PK complex assembly and DSBs repair activity via NHEJ pathway. Targeting GCN5-mediated K525 Kcr of DNA-PKcs may be a promising therapeutic strategy for improving the outcome of cancer radiotherapy.
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Affiliation(s)
- Yang Han
- Department of Radiation Biology, Beijing Key Laboratory for Radiobiology, Beijing Institute of Radiation Medicine, Beijing, China
| | - Hongling Zhao
- Department of Radiation Biology, Beijing Key Laboratory for Radiobiology, Beijing Institute of Radiation Medicine, Beijing, China
| | - Gang Li
- School of Public Health, Institute for Environmental Medicine and Radiation Hygiene, University of South China, Hengyang, China
- Department of Hospital Infection Control, Shenzhen Luohu Peoples Hospital, Shenzhen, China
| | - Jin Jia
- School of Medicine, University of South China, Hengyang, China
| | - Hejiang Guo
- Department of Radiation Biology, Beijing Key Laboratory for Radiobiology, Beijing Institute of Radiation Medicine, Beijing, China
| | - Jinpeng Tan
- School of Medicine, University of South China, Hengyang, China
| | - Xingyao Sun
- School of Medicine, University of South China, Hengyang, China
| | - Saiyu Li
- School of life Sciences, Hebei University, Baoding, China
| | - Qian Ran
- Laboratory of Radiation Biology, Laboratory Medicine Center, Department of Blood Transfusion, The Second Affiliated Hospital, Army Military Medical University, Chongqing, China
| | - Chenjun Bai
- Department of Radiation Biology, Beijing Key Laboratory for Radiobiology, Beijing Institute of Radiation Medicine, Beijing, China
| | - Yongqing Gu
- Department of Radiation Biology, Beijing Key Laboratory for Radiobiology, Beijing Institute of Radiation Medicine, Beijing, China
| | - ZhongJun Li
- Laboratory of Radiation Biology, Laboratory Medicine Center, Department of Blood Transfusion, The Second Affiliated Hospital, Army Military Medical University, Chongqing, China.
| | - Hua Guan
- Department of Radiation Biology, Beijing Key Laboratory for Radiobiology, Beijing Institute of Radiation Medicine, Beijing, China.
| | - Shanshan Gao
- Department of Radiation Biology, Beijing Key Laboratory for Radiobiology, Beijing Institute of Radiation Medicine, Beijing, China.
| | - Ping-Kun Zhou
- Department of Radiation Biology, Beijing Key Laboratory for Radiobiology, Beijing Institute of Radiation Medicine, Beijing, China.
- School of Public Health, Institute for Environmental Medicine and Radiation Hygiene, University of South China, Hengyang, China.
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Feng P, Wang Y, Liu N, Chen Y, Hu Y, Huang Z, Liu Y, Zheng S, Jiang T, Xiao X, Dai W, Huang P, Xia Y. High expression of PPP1CC promotes NHEJ-mediated DNA repair leading to radioresistance and poor prognosis in nasopharyngeal carcinoma. Cell Death Differ 2024; 31:683-696. [PMID: 38589496 PMCID: PMC11094031 DOI: 10.1038/s41418-024-01287-5] [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: 08/08/2023] [Revised: 03/19/2024] [Accepted: 03/20/2024] [Indexed: 04/10/2024] Open
Abstract
Protein phosphatase 1 catalytic subunit gamma (PPP1CC) promotes DNA repair and tumor development and progression, however, its underlying mechanisms remain unclear. This study investigated the molecular mechanism of PPP1CC's involvement in DNA repair and the potential clinical implications. High expression of PPP1CC was significantly correlated with radioresistance and poor prognosis in human nasopharyngeal carcinoma (NPC) patients. The mechanistic study revealed that PPP1CC bound to Ku70/Ku80 heterodimers and activated DNA-PKcs by promoting DNA-PK holoenzyme formation, which enhanced nonhomologous end junction (NHEJ) -mediated DNA repair and led to radioresistance. Importantly, BRCA1-BRCA2-containing complex subunit 3 (BRCC3) interacted with PPP1CC to enhance its stability by removing the K48-linked polyubiquitin chain at Lys234 to prevent PPP1CC degradation. Therefore, BRCC3 helped the overexpressed PPP1CC to maintain its high protein level, thereby sustaining the elevation of DNA repair capacity and radioresistance. Our study identified the molecular mechanism by which PPP1CC promotes NHEJ-mediated DNA repair and radioresistance, suggesting that the BRCC3-PPP1CC-Ku70 axis is a potential therapeutic target to improve the efficacy of radiotherapy.
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Affiliation(s)
- Ping Feng
- State Key Laboratory of Oncology in South China; Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy; Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou, 510060, China
- Department of Radiation Oncology, Sun Yat-sen University Cancer Center, Guangzhou, 510060, China
| | - Ying Wang
- State Key Laboratory of Oncology in South China; Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy; Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou, 510060, China
- Department of Radiation Oncology, Sun Yat-sen University Cancer Center, Guangzhou, 510060, China
| | - Na Liu
- State Key Laboratory of Oncology in South China; Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy; Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou, 510060, China
- Department of Radiation Oncology, Sun Yat-sen University Cancer Center, Guangzhou, 510060, China
| | - Yanming Chen
- The Second Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, 421001, Hunan, China
| | - Yujun Hu
- State Key Laboratory of Oncology in South China; Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy; Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou, 510060, China
- Department of Radiation Oncology, Sun Yat-sen University Cancer Center, Guangzhou, 510060, China
| | - Zilu Huang
- State Key Laboratory of Oncology in South China; Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy; Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou, 510060, China
- Department of Radiation Oncology, Sun Yat-sen University Cancer Center, Guangzhou, 510060, China
| | - Ya Liu
- State Key Laboratory of Oncology in South China; Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy; Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou, 510060, China
- Department of Radiation Oncology, Sun Yat-sen University Cancer Center, Guangzhou, 510060, China
| | - Shuohan Zheng
- State Key Laboratory of Oncology in South China; Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy; Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou, 510060, China
- Department of Radiation Oncology, Sun Yat-sen University Cancer Center, Guangzhou, 510060, China
| | - Tongchao Jiang
- State Key Laboratory of Oncology in South China; Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy; Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou, 510060, China
- Department of Radiation Oncology, Sun Yat-sen University Cancer Center, Guangzhou, 510060, China
| | - Xiang Xiao
- State Key Laboratory of Oncology in South China; Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy; Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou, 510060, China
- Department of Radiation Oncology, Sun Yat-sen University Cancer Center, Guangzhou, 510060, China
| | - Wei Dai
- Department of Clinical Oncology, University of Hong Kong, Hong Kong (SAR), China
- University of Hong Kong-Shenzhen Hospital, Shenzhen, China
| | - Peng Huang
- State Key Laboratory of Oncology in South China; Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy; Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou, 510060, China.
- Metabolic Innovation Center, Sun Yat-sen University, Guangzhou, 510060, China.
| | - Yunfei Xia
- State Key Laboratory of Oncology in South China; Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy; Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou, 510060, China.
- Department of Radiation Oncology, Sun Yat-sen University Cancer Center, Guangzhou, 510060, China.
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Ubiquitination and degradation of SIK2 by DNA-PKcs deficiency promote radiation-induced mitotic catastrophe. Genes Dis 2022; 10:313-316. [DOI: 10.1016/j.gendis.2022.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 01/22/2022] [Accepted: 02/22/2022] [Indexed: 11/21/2022] Open
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Schreiter T, Gieseler RK, Vílchez-Vargas R, Jauregui R, Sowa JP, Klein-Scory S, Broering R, Croner RS, Treckmann JW, Link A, Canbay A. Transcriptome-Wide Analysis of Human Liver Reveals Age-Related Differences in the Expression of Select Functional Gene Clusters and Evidence for a PPP1R10-Governed 'Aging Cascade'. Pharmaceutics 2021; 13:pharmaceutics13122009. [PMID: 34959291 PMCID: PMC8709089 DOI: 10.3390/pharmaceutics13122009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Revised: 11/17/2021] [Accepted: 11/21/2021] [Indexed: 12/27/2022] Open
Abstract
A transcriptome-wide analysis of human liver for demonstrating differences between young and old humans has not yet been performed. However, identifying major age-related alterations in hepatic gene expression may pinpoint ontogenetic shifts with important hepatic and systemic consequences, provide novel pharmacogenetic information, offer clues to efficiently counteract symptoms of old age, and improve the overarching understanding of individual decline. Next-generation sequencing (NGS) data analyzed by the Mann-Whitney nonparametric test and Ensemble Feature Selection (EFS) bioinformatics identified 44 transcripts among 60,617 total and 19,986 protein-encoding transcripts that significantly (p = 0.0003 to 0.0464) and strikingly (EFS score > 0.3:16 transcripts; EFS score > 0.2:28 transcripts) differ between young and old livers. Most of these age-related transcripts were assigned to the categories 'regulome', 'inflammaging', 'regeneration', and 'pharmacogenes'. NGS results were confirmed by quantitative real-time polymerase chain reaction. Our results have important implications for the areas of ontogeny/aging and the age-dependent increase in major liver diseases. Finally, we present a broadly substantiated and testable hypothesis on a genetically governed 'aging cascade', wherein PPP1R10 acts as a putative ontogenetic master regulator, prominently flanked by IGFALS and DUSP1. This transcriptome-wide analysis of human liver offers potential clues towards developing safer and improved therapeutic interventions against major liver diseases and increased insights into key mechanisms underlying aging.
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Affiliation(s)
- Thomas Schreiter
- Department of Medicine, University Hospital Knappschaftskrankenhaus Bochum, Ruhr University Bochum, 44892 Bochum, Germany; (T.S.); (R.K.G.); (J.-P.S.); (S.K.-S.)
- Laboratory of Immunology & Molecular Biology, University Hospital Knappschaftskrankenhaus Bochum, Ruhr University Bochum, 44892 Bochum, Germany
| | - Robert K. Gieseler
- Department of Medicine, University Hospital Knappschaftskrankenhaus Bochum, Ruhr University Bochum, 44892 Bochum, Germany; (T.S.); (R.K.G.); (J.-P.S.); (S.K.-S.)
- Laboratory of Immunology & Molecular Biology, University Hospital Knappschaftskrankenhaus Bochum, Ruhr University Bochum, 44892 Bochum, Germany
| | - Ramiro Vílchez-Vargas
- Department of Gastroenterology, Hepatology, and Infectious Diseases, Medical Faculty, Otto-von-Guericke University, 39120 Magdeburg, Germany; (R.V.-V.); (A.L.)
| | - Ruy Jauregui
- Data Science Grasslands, Grasslands Research Centre, AgResearch, Palmerston North 4410, New Zealand;
| | - Jan-Peter Sowa
- Department of Medicine, University Hospital Knappschaftskrankenhaus Bochum, Ruhr University Bochum, 44892 Bochum, Germany; (T.S.); (R.K.G.); (J.-P.S.); (S.K.-S.)
- Laboratory of Immunology & Molecular Biology, University Hospital Knappschaftskrankenhaus Bochum, Ruhr University Bochum, 44892 Bochum, Germany
| | - Susanne Klein-Scory
- Department of Medicine, University Hospital Knappschaftskrankenhaus Bochum, Ruhr University Bochum, 44892 Bochum, Germany; (T.S.); (R.K.G.); (J.-P.S.); (S.K.-S.)
- Laboratory of Immunology & Molecular Biology, University Hospital Knappschaftskrankenhaus Bochum, Ruhr University Bochum, 44892 Bochum, Germany
| | - Ruth Broering
- Department of Gastroenterology and Hepatology, University Hospital Essen, University of Duisburg-Essen, 45147 Essen, Germany;
| | - Roland S. Croner
- Department of General, Visceral, Vascular and Transplantation Surgery, Medical Faculty, Otto-von-Guericke University, 39120 Magdeburg, Germany;
| | - Jürgen W. Treckmann
- Department of General, Visceral and Transplantation Surgery, University Hospital Essen, University of Duisburg-Essen, 45147 Essen, Germany;
| | - Alexander Link
- Department of Gastroenterology, Hepatology, and Infectious Diseases, Medical Faculty, Otto-von-Guericke University, 39120 Magdeburg, Germany; (R.V.-V.); (A.L.)
| | - Ali Canbay
- Department of Medicine, University Hospital Knappschaftskrankenhaus Bochum, Ruhr University Bochum, 44892 Bochum, Germany; (T.S.); (R.K.G.); (J.-P.S.); (S.K.-S.)
- Section of Hepatology and Gastroenterology, University Hospital Knappschaftskrankenhaus Bochum, Ruhr University Bochum, 44892 Bochum, Germany
- Correspondence: ; Tel.: +49-234-299-3401
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6
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Li Y, Kardell MB, Wang F, Wang L, Zhu S, Bessho T, Peng A. The Sm core components of small nuclear ribonucleoproteins promote homologous recombination repair. DNA Repair (Amst) 2021; 108:103244. [PMID: 34768043 DOI: 10.1016/j.dnarep.2021.103244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 10/01/2021] [Accepted: 10/29/2021] [Indexed: 11/17/2022]
Abstract
DNA Double strand breaks (DSBs) are highly hazardous to the cell, and are repaired predominantly via non-homologous end joining (NHEJ) and homologous recombination (HR). Using DSB-mimicking DNA templates, our proteomic studies identified a group of Sm core proteins of small nuclear ribonucleoproteins (snRNPs) as potential DSB-associated proteins. We further confirmed that these Sm proteins were recruited to laser-induced DNA damage sites, and co-localized with established DNA damage repair factors. Depletion of Sm-D3 or Sm-B induced accumulation of γ-H2AX, and impaired the repair efficiency of HR, but not NHEJ. Furthermore, disruption of Sm-D3 reduced the protein level of HR factors, especially RAD51 and CHK1, but caused no change in the expression of repair factors involved in NHEJ. Mechanistically, Sm-D3 proteins bound RAD51, suppressed the ubiquitination of RAD51, and mediated the stabilization of RAD51; Sm-D3 depletion particularly impacted the level of RAD51 and CHK1 on damaged chromatin. As such, our studies characterized a role of Sm proteins in HR repair, via a new mechanism that is distinct from their conventional functions in RNA processing and gene regulation, but consistent with their direct recruitment to DNA damage sites and association with repair factors.
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Affiliation(s)
- Yanqiu Li
- Department of Oral Biology, University of Nebraska Medical Center, Lincoln, NE, USA
| | - Mary Bridget Kardell
- Department of Oral Biology, University of Nebraska Medical Center, Lincoln, NE, USA
| | - Feifei Wang
- Department of Oral Biology, University of Nebraska Medical Center, Lincoln, NE, USA
| | - Ling Wang
- Department of Oral Biology, University of Nebraska Medical Center, Lincoln, NE, USA
| | - Songli Zhu
- Department of Oral Biology, University of Nebraska Medical Center, Lincoln, NE, USA
| | - Tadayoshi Bessho
- The Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, USA
| | - Aimin Peng
- Department of Oral Biology, University of Nebraska Medical Center, Lincoln, NE, USA.
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Isobe SY, Hiraga SI, Nagao K, Sasanuma H, Donaldson AD, Obuse C. Protein phosphatase 1 acts as a RIF1 effector to suppress DSB resection prior to Shieldin action. Cell Rep 2021; 36:109383. [PMID: 34260925 PMCID: PMC8293623 DOI: 10.1016/j.celrep.2021.109383] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 04/14/2021] [Accepted: 06/21/2021] [Indexed: 12/29/2022] Open
Abstract
DNA double-strand breaks (DSBs) are repaired mainly by non-homologous end joining (NHEJ) or homologous recombination (HR). RIF1 negatively regulates resection through the effector Shieldin, which associates with a short 3' single-stranded DNA (ssDNA) overhang by the MRN (MRE11-RAD50-NBS1) complex, to prevent further resection and HR repair. In this study, we show that RIF1, but not Shieldin, inhibits the accumulation of CtIP at DSB sites immediately after damage, suggesting that RIF1 has another effector besides Shieldin. We find that protein phosphatase 1 (PP1), a known RIF1 effector in replication, localizes at damage sites dependent on RIF1, where it suppresses downstream CtIP accumulation and limits the resection by the MRN complex. PP1 therefore acts as a RIF1 effector distinct from Shieldin. Furthermore, PP1 deficiency in the context of Shieldin depletion elevates HR immediately after irradiation. We conclude that PP1 inhibits resection before the action of Shieldin to prevent precocious HR in the early phase of the damage response.
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Affiliation(s)
- Shin-Ya Isobe
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama-Cho, Toyonaka, Osaka 560-0043, Japan
| | - Shin-Ichiro Hiraga
- Institute of Medical Sciences, School of Medicine, Medical Sciences & Nutrition, University of Aberdeen, Aberdeen AB25 2ZD, UK
| | - Koji Nagao
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama-Cho, Toyonaka, Osaka 560-0043, Japan
| | - Hiroyuki Sasanuma
- Department of Genome Medicine, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Anne D Donaldson
- Institute of Medical Sciences, School of Medicine, Medical Sciences & Nutrition, University of Aberdeen, Aberdeen AB25 2ZD, UK
| | - Chikashi Obuse
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama-Cho, Toyonaka, Osaka 560-0043, Japan.
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8
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Jia C, Wang Q, Yao X, Yang J. The Role of DNA Damage Induced by Low/High Dose Ionizing Radiation in Cell Carcinogenesis. EXPLORATORY RESEARCH AND HYPOTHESIS IN MEDICINE 2021; 000:000-000. [DOI: 10.14218/erhm.2021.00020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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9
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Hanaki S, Habara M, Masaki T, Maeda K, Sato Y, Nakanishi M, Shimada M. PP1 regulatory subunit NIPP1 regulates transcription of E2F1 target genes following DNA damage. Cancer Sci 2021; 112:2739-2752. [PMID: 33939241 PMCID: PMC8253265 DOI: 10.1111/cas.14924] [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: 02/03/2021] [Revised: 04/14/2021] [Accepted: 04/14/2021] [Indexed: 12/21/2022] Open
Abstract
DNA damage induces transcriptional repression of E2F1 target genes and a reduction in histone H3‐Thr11 phosphorylation (H3‐pThr11) at E2F1 target gene promoters. Dephosphorylation of H3‐pThr11 is partly mediated by Chk1 kinase and protein phosphatase 1γ (PP1γ) phosphatase. Here, we isolated NIPP1 as a regulator of PP1γ‐mediated H3‐pThr11 by surveying nearly 200 PP1 interactor proteins. We found that NIPP1 inhibits PP1γ‐mediated dephosphorylation of H3‐pThr11 both in vivo and in vitro. By generating NIPP1‐depleted cells, we showed that NIPP1 is required for cell proliferation and the expression of E2F1 target genes. Upon DNA damage, activated protein kinase A (PKA) phosphorylated the NIPP1‐Ser199 residue, adjacent to the PP1 binding motif (RVxF), and triggered the dissociation of NIPP1 from PP1γ, leading to the activation of PP1γ. Furthermore, the inhibition of PKA activity led to the activation of E2F target genes. Statistical analysis confirmed that the expression of NIPP1 was positively correlated with E2F target genes. Taken together, these findings demonstrate that the PP1 regulatory subunit NIPP1 modulates E2F1 target genes by linking PKA and PP1γ during DNA damage.
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Affiliation(s)
- Shunsuke Hanaki
- Department of Biochemistry, Joint Faculty of Veterinary Science, Yamaguchi University, Yamaguchi, Japan
| | - Makoto Habara
- Department of Biochemistry, Joint Faculty of Veterinary Science, Yamaguchi University, Yamaguchi, Japan
| | - Takahiro Masaki
- Department of Biochemistry, Joint Faculty of Veterinary Science, Yamaguchi University, Yamaguchi, Japan
| | - Keisuke Maeda
- Department of Biochemistry, Joint Faculty of Veterinary Science, Yamaguchi University, Yamaguchi, Japan
| | - Yuki Sato
- Department of Biochemistry, Joint Faculty of Veterinary Science, Yamaguchi University, Yamaguchi, Japan
| | - Makoto Nakanishi
- Division of Cancer Biology, Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Midori Shimada
- Department of Biochemistry, Joint Faculty of Veterinary Science, Yamaguchi University, Yamaguchi, Japan
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10
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Abbasi S, Schild-Poulter C. Identification of Ku70 Domain-Specific Interactors Using BioID2. Cells 2021; 10:cells10030646. [PMID: 33799447 PMCID: PMC8001828 DOI: 10.3390/cells10030646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 03/04/2021] [Accepted: 03/10/2021] [Indexed: 11/23/2022] Open
Abstract
Since its inception, proximity-dependent biotin identification (BioID), an in vivo biochemical screening method to identify proximal protein interactors, has seen extensive developments. Improvements and variants of the original BioID technique are being reported regularly, each expanding upon the existing potential of the original technique. While this is advancing our capabilities to study protein interactions under different contexts, we have yet to explore the full potential of the existing BioID variants already at our disposal. Here, we used BioID2 in an innovative manner to identify and map domain-specific protein interactions for the human Ku70 protein. Four HEK293 cell lines were created, each stably expressing various BioID2-tagged Ku70 segments designed to collectively identify factors that interact with different regions of Ku70. Historically, although many interactions have been mapped to the C-terminus of the Ku70 protein, few have been mapped to the N-terminal von Willebrand A-like domain, a canonical protein-binding domain ideally situated as a site for protein interaction. Using this segmented approach, we were able to identify domain-specific interactors as well as evaluate advantages and drawbacks of the BioID2 technique. Our study identifies several potential new Ku70 interactors and validates RNF113A and Spindly as proteins that contact or co-localize with Ku in a Ku70 vWA domain-specific manner.
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11
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Gui SJ, Ding RL, Wan YP, Zhou L, Chen XJ, Zeng GQ, He CZ. Knockdown of annexin VII enhances nasopharyngeal carcinoma cell radiosensitivity in vivo and in vitro. Cancer Biomark 2021; 28:129-139. [PMID: 31958076 DOI: 10.3233/cbm-190739] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND Radioresistance leads to treatment failure in patients with nasopharyngeal carcinoma (NPC). Thus, enhancing the radiosensitivity of NPC cells would likely increase the effectiveness of radiotherapy. Annexin VII (Annexin A7, ANXA7) might be a tumor promoter in NPC but its functions in radiosensitivity remain unclear. METHODS NPC cell lines CNE2-shANXA7 and CNE2-pLKO.1 were generated and CNE2-shANXA7 nude mice xenograft tumor models were established. The main effects and molecular mechanisms of ANXA7 knockdown in NPC radiosensitivity were studied in vitro and in vivo by analyzing cell viability, clonogenicity, apoptosis, cell cycle distribution, tumor radioresponse and immunohistochemistry assay. RESULTS ANXA7 knockdown revealed potentially enhanced NPC cell radiosensitivity via apoptosis and increased the cell number at the G2/M phase. In the xenograft model, NPC cells with ANXA7 knockdown were dramatically sensitive to irradiation and tumor growth was significantly suppressed. Compared to CNE2-pLKO.1 xenografts, CNE2-shANXA7 showed more γ-H2AX foci and less phospho-DNA PKcs. CONCLUSIONS ANXA7 knockdown increased the radiosensitivity of NPC by enhancing apoptosis, modulating the cell cycle distribution into more radiosensitive phases, promoting DNA damage, and inhibiting repair. We showed that decreased ANXA7 levels enhanced radiosensitivity and provided insights into the therapeutic targets for NPC radiotherapy.
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Affiliation(s)
- Si-Jie Gui
- Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi, China
| | - Ru-Lei Ding
- School of Nursing, University of South China, Hengyang, Hunan, China
| | - Yan-Ping Wan
- School of Nursing, University of South China, Hengyang, Hunan, China
| | - Li Zhou
- School of Nursing, University of South China, Hengyang, Hunan, China
| | - Xu-Jun Chen
- Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi, China
| | - Gu-Qing Zeng
- School of Nursing, University of South China, Hengyang, Hunan, China
| | - Chao-Zhu He
- Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi, China
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12
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Yue X, Bai C, Xie D, Ma T, Zhou PK. DNA-PKcs: A Multi-Faceted Player in DNA Damage Response. Front Genet 2020; 11:607428. [PMID: 33424929 PMCID: PMC7786053 DOI: 10.3389/fgene.2020.607428] [Citation(s) in RCA: 80] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 12/01/2020] [Indexed: 12/17/2022] Open
Abstract
DNA-dependent protein kinase catalytic subunit (DNA-PKcs) is a member of the phosphatidylinositol 3-kinase related kinase family, which can phosphorylate more than 700 substrates. As the core enzyme, DNA-PKcs forms the active DNA-PK holoenzyme with the Ku80/Ku70 heterodimer to play crucial roles in cellular DNA damage response (DDR). Once DNA double strand breaks (DSBs) occur in the cells, DNA-PKcs is promptly recruited into damage sites and activated. DNA-PKcs is auto-phosphorylated and phosphorylated by Ataxia-Telangiectasia Mutated at multiple sites, and phosphorylates other targets, participating in a series of DDR and repair processes, which determine the cells' fates: DSBs NHEJ repair and pathway choice, replication stress response, cell cycle checkpoints, telomeres length maintenance, senescence, autophagy, etc. Due to the special and multi-faceted roles of DNA-PKcs in the cellular responses to DNA damage, it is important to precisely regulate the formation and dynamic of its functional complex and activities for guarding genomic stability. On the other hand, targeting DNA-PKcs has been considered as a promising strategy of exploring novel radiosensitizers and killing agents of cancer cells. Combining DNA-PKcs inhibitors with radiotherapy can effectively enhance the efficacy of radiotherapy, offering more possibilities for cancer therapy.
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Affiliation(s)
- Xiaoqiao Yue
- School of Public Health, University of South China, Hengyang, China.,Department of Radiation Biology, Beijing Key Laboratory for Radiobiology, Beijing Institute of Radiation Medicine, Beijing, China
| | - Chenjun Bai
- Department of Radiation Biology, Beijing Key Laboratory for Radiobiology, Beijing Institute of Radiation Medicine, Beijing, China
| | - Dafei Xie
- Department of Radiation Biology, Beijing Key Laboratory for Radiobiology, Beijing Institute of Radiation Medicine, Beijing, China
| | - Teng Ma
- Department of Cellular and Molecular Biology, Beijing Chest Hospital, Capital Medical University/Beijing Tuberculosis and Thoracic Tumor Research Institute, Beijing, China
| | - Ping-Kun Zhou
- Department of Radiation Biology, Beijing Key Laboratory for Radiobiology, Beijing Institute of Radiation Medicine, Beijing, China
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13
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Casamayor A, Ariño J. Controlling Ser/Thr protein phosphatase PP1 activity and function through interaction with regulatory subunits. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2020; 122:231-288. [PMID: 32951813 DOI: 10.1016/bs.apcsb.2020.06.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Protein phosphatase 1 is a major Ser/Thr protein phosphatase activity in eukaryotic cells. It is composed of a catalytic polypeptide (PP1C), with little substrate specificity, that interacts with a large variety of proteins of diverse structure (regulatory subunits). The diversity of holoenzymes that can be formed explain the multiplicity of cellular functions under the control of this phosphatase. In quite a few cases, regulatory subunits have an inhibitory role, downregulating the activity of the phosphatase. In this chapter we shall introduce PP1C and review the most relevant families of PP1C regulatory subunits, with particular emphasis in describing the structural basis for their interaction.
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Affiliation(s)
- Antonio Casamayor
- Institut de Biotecnologia i Biomedicina & Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Cerdanyola, del Vallès, Spain
| | - Joaquín Ariño
- Institut de Biotecnologia i Biomedicina & Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Cerdanyola, del Vallès, Spain
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14
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Zhu S, Paydar M, Wang F, Li Y, Wang L, Barrette B, Bessho T, Kwok BH, Peng A. Kinesin Kif2C in regulation of DNA double strand break dynamics and repair. eLife 2020; 9:53402. [PMID: 31951198 PMCID: PMC7012618 DOI: 10.7554/elife.53402] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 01/16/2020] [Indexed: 12/12/2022] Open
Abstract
DNA double strand breaks (DSBs) have detrimental effects on cell survival and genomic stability, and are related to cancer and other human diseases. In this study, we identified microtubule-depolymerizing kinesin Kif2C as a protein associated with DSB-mimicking DNA templates and known DSB repair proteins in Xenopus egg extracts and mammalian cells. The recruitment of Kif2C to DNA damage sites was dependent on both PARP and ATM activities. Kif2C knockdown or knockout led to accumulation of endogenous DNA damage, DNA damage hypersensitivity, and reduced DSB repair via both NHEJ and HR. Interestingly, Kif2C depletion, or inhibition of its microtubule depolymerase activity, reduced the mobility of DSBs, impaired the formation of DNA damage foci, and decreased the occurrence of foci fusion and resolution. Taken together, our study established Kif2C as a new player of the DNA damage response, and presented a new mechanism that governs DSB dynamics and repair.
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Affiliation(s)
- Songli Zhu
- Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Omaha, United States
| | - Mohammadjavad Paydar
- Institute for Research in Immunology and Cancer (IRIC), Département de médecine, Université de Montréal, Montréal, Canada
| | - Feifei Wang
- Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Omaha, United States.,Institute of Physical Science and Information Technology, Anhui University, Hefei, China
| | - Yanqiu Li
- Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Omaha, United States
| | - Ling Wang
- Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Omaha, United States
| | - Benoit Barrette
- Institute for Research in Immunology and Cancer (IRIC), Département de médecine, Université de Montréal, Montréal, Canada
| | - Tadayoshi Bessho
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, United States
| | - Benjamin H Kwok
- Institute for Research in Immunology and Cancer (IRIC), Département de médecine, Université de Montréal, Montréal, Canada
| | - Aimin Peng
- Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Omaha, United States
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15
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Cell Cycle and DNA Repair Regulation in the Damage Response: Protein Phosphatases Take Over the Reins. Int J Mol Sci 2020; 21:ijms21020446. [PMID: 31936707 PMCID: PMC7014277 DOI: 10.3390/ijms21020446] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 12/29/2019] [Accepted: 01/02/2020] [Indexed: 12/14/2022] Open
Abstract
Cells are constantly suffering genotoxic stresses that affect the integrity of our genetic material. Genotoxic insults must be repaired to avoid the loss or inappropriate transmission of the genetic information, a situation that could lead to the appearance of developmental abnormalities and tumorigenesis. To combat this threat, eukaryotic cells have evolved a set of sophisticated molecular mechanisms that are collectively known as the DNA damage response (DDR). This surveillance system controls several aspects of the cellular response, including the detection of lesions, a temporary cell cycle arrest, and the repair of the broken DNA. While the regulation of the DDR by numerous kinases has been well documented over the last decade, the complex roles of protein dephosphorylation have only recently begun to be investigated. Here, we review recent progress in the characterization of DDR-related protein phosphatases during the response to a DNA lesion, focusing mainly on their ability to modulate the DNA damage checkpoint and the repair of the damaged DNA. We also discuss their protein composition and structure, target specificity, and biochemical regulation along the different stages encompassed in the DDR. The compilation of this information will allow us to better comprehend the physiological significance of protein dephosphorylation in the maintenance of genome integrity and cell viability in response to genotoxic stress.
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16
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Dziegielewski J, Bońkowska MA, Poniecka EA, Heo J, Du K, Crittenden RB, Bender TP, Brautigan DL, Larner JM. Deletion of the SAPS1 subunit of protein phosphatase 6 in mice increases radiosensitivity and impairs the cellular DNA damage response. DNA Repair (Amst) 2019; 85:102737. [PMID: 31751917 DOI: 10.1016/j.dnarep.2019.102737] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 09/17/2019] [Accepted: 10/15/2019] [Indexed: 12/24/2022]
Abstract
Cellular responses to DNA damage include activation of DNA-dependent protein kinase (DNA-PK) through, among others, the serine/threonine protein phosphatase 6 (PP6). We previously showed that recognition of DNA-PKcs is mediated by the SAPS1 PP6 regulatory subunit. Here, we report and characterize a SAPS1 null mouse and investigate the effects of deletion on DNA damage signaling and repair. Strikingly, neither SAPS1-null animals nor cells derived from them show gross defects, unless subjected to DNA damage by radiation or chemical agents. The overall survival of SAPS1-null animals following whole body irradiation is significantly shortened as compared to wild-type mice, and the clonogenic survival of null cells subjected to ionizing radiation is reduced. The dephosphorylation of DNA damage/repair markers, such as γH2AX, p53 and Kap1, is diminished in SAPS1-null cells as compared to wild-type controls. Our results demonstrate that loss of SAPS1 confers sensitivity to DNA damage and confirms previously reported cellular phenotypes of SAPS1 knock-down in human glioma cells. The results support a role for PP6 regulatory subunit SAPS1 in DNA damage responses, and offer a novel target for sensitization to enhance current tumor therapies, with a potential for limited deleterious side effects.
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Affiliation(s)
- Jaroslaw Dziegielewski
- Center for Cell Signaling, University of Virginia School of Medicine, Charlottesville, VA 22908, USA; Department of Radiation Oncology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Magdalena A Bońkowska
- Center for Cell Signaling, University of Virginia School of Medicine, Charlottesville, VA 22908, USA; Department of Microbiology, Immunology and Cancer Biology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Ewa A Poniecka
- Center for Cell Signaling, University of Virginia School of Medicine, Charlottesville, VA 22908, USA; Department of Microbiology, Immunology and Cancer Biology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Jinho Heo
- Center for Cell Signaling, University of Virginia School of Medicine, Charlottesville, VA 22908, USA; Department of Microbiology, Immunology and Cancer Biology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Kangping Du
- Center for Cell Signaling, University of Virginia School of Medicine, Charlottesville, VA 22908, USA; Department of Radiation Oncology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Rowena B Crittenden
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA; Beirne B. Carter Center for Immunology Research, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Timothy P Bender
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA; Beirne B. Carter Center for Immunology Research, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - David L Brautigan
- Center for Cell Signaling, University of Virginia School of Medicine, Charlottesville, VA 22908, USA; Department of Microbiology, Immunology and Cancer Biology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - James M Larner
- Center for Cell Signaling, University of Virginia School of Medicine, Charlottesville, VA 22908, USA; Department of Radiation Oncology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA.
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17
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Ramos F, Villoria MT, Alonso-Rodríguez E, Clemente-Blanco A. Role of protein phosphatases PP1, PP2A, PP4 and Cdc14 in the DNA damage response. Cell Stress 2019; 3:70-85. [PMID: 31225502 PMCID: PMC6551743 DOI: 10.15698/cst2019.03.178] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Maintenance of genome integrity is fundamental for cellular physiology. Our hereditary information encoded in the DNA is intrinsically susceptible to suffer variations, mostly due to the constant presence of endogenous and environmental genotoxic stresses. Genomic insults must be repaired to avoid loss or inappropriate transmission of the genetic information, a situation that could lead to the appearance of developmental anomalies and tumorigenesis. To safeguard our genome, cells have evolved a series of mechanisms collectively known as the DNA damage response (DDR). This surveillance system regulates multiple features of the cellular response, including the detection of the lesion, a transient cell cycle arrest and the restoration of the broken DNA molecule. While the role of multiple kinases in the DDR has been well documented over the last years, the intricate roles of protein dephosphorylation have only recently begun to be addressed. In this review, we have compiled recent information about the function of protein phosphatases PP1, PP2A, PP4 and Cdc14 in the DDR, focusing mainly on their capacity to regulate the DNA damage checkpoint and the repair mechanism encompassed in the restoration of a DNA lesion.
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Affiliation(s)
- Facundo Ramos
- Cell Cycle and Genome Stability Group. Institute of Functional Biology and Genomics (IBFG). Spanish National Research Council (CSIC), University of Salamanca (USAL), C/Zacarías González 2, Salamanca 37007, SPAIN
| | - María Teresa Villoria
- Cell Cycle and Genome Stability Group. Institute of Functional Biology and Genomics (IBFG). Spanish National Research Council (CSIC), University of Salamanca (USAL), C/Zacarías González 2, Salamanca 37007, SPAIN
| | - Esmeralda Alonso-Rodríguez
- Cell Cycle and Genome Stability Group. Institute of Functional Biology and Genomics (IBFG). Spanish National Research Council (CSIC), University of Salamanca (USAL), C/Zacarías González 2, Salamanca 37007, SPAIN
| | - Andrés Clemente-Blanco
- Cell Cycle and Genome Stability Group. Institute of Functional Biology and Genomics (IBFG). Spanish National Research Council (CSIC), University of Salamanca (USAL), C/Zacarías González 2, Salamanca 37007, SPAIN
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18
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Wang F, Zhu S, Fisher LA, Wang L, Eurek NJ, Wahl JK, Lan L, Peng A. Phosphatase 1 Nuclear Targeting Subunit Mediates Recruitment and Function of Poly (ADP-Ribose) Polymerase 1 in DNA Repair. Cancer Res 2019; 79:2526-2535. [PMID: 30733193 DOI: 10.1158/0008-5472.can-18-1673] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 10/26/2018] [Accepted: 01/31/2019] [Indexed: 12/17/2022]
Abstract
PARP, particularly PARP1, plays an essential role in the detection and repair of DNA single-strand breaks and double-strand breaks. PARP1 accumulates at DNA damage sites within seconds after DNA damage to catalyze the massive induction of substrate protein poly ADP-ribosylation (PARylation). However, the molecular mechanisms underlying the recruitment and activation of PARP1 in DNA repair are not fully understood. Here we show that phosphatase 1 nuclear targeting subunit 1 (PNUTS) is a robust binding partner of PARP1. Inhibition of PNUTS led to strong accumulation of endogenous DNA damage and sensitized the cellular response to a wide range of DNA-damaging agents, implicating PNUTS as an essential and multifaceted regulator of DNA repair. Recruitment of PNUTS to laser-induced DNA damage was similar to that of PARP1, and depletion or inhibition of PARP1 abrogated recruitment of PNUTS to sites of DNA damage. Conversely, PNUTS was required for efficient induction of substrate PARylation after DNA damage. PNUTS bound the BRCA1 C-terminal (BRCT) domain of PARP1 and was required for the recruitment of PARP1 to sites of DNA damage. Finally, depletion of PNUTS rendered cancer cells hypersensitive to PARP inhibition. Taken together, our study characterizes PNUTS as an essential partner of PARP1 in DNA repair and a potential drug target in cancer therapy. SIGNIFICANCE: These findings reveal PNUTS as an essential functional partner of PARP1 in DNA repair and suggest its inhibition as a potential therapeutic strategy in conjunction with DNA-damaging agents or PARP inhibitors.See related commentary by Murai and Pommier, p. 2460.
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Affiliation(s)
- Feifei Wang
- Institute of Physical Science and Information Technology, Anhui University, Hefei, P.R. China.,Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Lincoln, Nebraska
| | - Songli Zhu
- Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Lincoln, Nebraska
| | - Laura A Fisher
- Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Lincoln, Nebraska
| | - Ling Wang
- Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Lincoln, Nebraska
| | - Nicholas J Eurek
- Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Lincoln, Nebraska
| | - James K Wahl
- Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Lincoln, Nebraska
| | - Li Lan
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.,UPMC Hillman Cancer Center, Pittsburgh, Pennsylvania
| | - Aimin Peng
- Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Lincoln, Nebraska.
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19
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Abbasi S, Schild-Poulter C. Mapping the Ku Interactome Using Proximity-Dependent Biotin Identification in Human Cells. J Proteome Res 2019; 18:1064-1077. [PMID: 30585729 DOI: 10.1021/acs.jproteome.8b00771] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The Ku heterodimer, composed of Ku70 and Ku80, is best characterized for its role in repairing double-stranded DNA breaks but is also known to participate in other regulatory processes. Despite our understanding of Ku protein interplay during DNA repair, the extent of Ku's protein interactions in other processes has never been fully determined. Using proximity-dependent biotin identification (BioID) and affinity purification coupled to mass spectrometry (AP-MS) with wild-type Ku70, we identified candidate proteins that interact with the Ku heterodimer in HEK293 cells, in the absence of exogenously induced DNA damage. BioID analysis identified approximately 250 nuclear proteins, appearing in at least two replicates, including known Ku-interacting factors such as MRE11A, WRN, and NCOA6. Meanwhile, AP-MS analysis identified approximately 50 candidate proteins. Of the novel protein interactors identified, many were involved in functions already suspected to involve Ku such as transcriptional regulation, DNA replication, and DNA repair, while several others suggest that Ku may be involved in additional functions such as RNA metabolism, chromatin-remodeling, and microtubule dynamics. Using a combination of BioID and AP-MS, this is the first report that comprehensively characterizes the Ku protein interaction landscape, revealing new cellular processes and protein complexes involving the Ku complex.
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Affiliation(s)
- Sanna Abbasi
- Robarts Research Institute and Department of Biochemistry, Schulich School of Medicine and Dentistry , University of Western Ontario , London , Ontario N6A 5B7 , Canada
| | - Caroline Schild-Poulter
- Robarts Research Institute and Department of Biochemistry, Schulich School of Medicine and Dentistry , University of Western Ontario , London , Ontario N6A 5B7 , Canada
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20
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Role of protein phosphatases in the cancer microenvironment. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2019; 1866:144-152. [DOI: 10.1016/j.bbamcr.2018.07.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 06/29/2018] [Accepted: 07/11/2018] [Indexed: 12/15/2022]
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21
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Wang F, Wang L, Fisher LA, Li C, Wang W, Peng A. Phosphatase 1 Nuclear Targeting Subunit (PNUTS) Regulates Aurora Kinases and Mitotic Progression. Mol Cancer Res 2018; 17:10-19. [PMID: 30190438 DOI: 10.1158/1541-7786.mcr-17-0670] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 05/31/2018] [Accepted: 08/27/2018] [Indexed: 11/16/2022]
Abstract
Mitotic progression is regulated largely by reversible phosphorylation events that are mediated by mitotic kinases and phosphatases. Protein phosphatase 1 (PP1) has been shown to play a crucial role in regulation of mitotic entry, progression, and exit. We previously observed, in Xenopus egg extracts, that phosphatase 1 nuclear targeting subunit (PPP1R10/PNUTS) acts as a mitotic regulator by negatively modulating PP1. This study investigates the role of PNUTS in mitotic progression in mammalian cells, and demonstrates that PNUTS expression is elevated in mitosis and depletion partially blocks mitotic entry. Cells that enter mitosis after PNUTS knockdown exhibit frequent chromosome mis-segregation. Aurora A/B kinase complexes and several kinetochore components are identified as PNUTS-associated proteins. PNUTS depletion suppresses the activation of Aurora A/B kinases, and disrupts the spatiotemporal regulation of the chromosomal passenger complex (CPC). PNUTS dynamically localizes to kinetochores, and is required for the activation of the spindle assembly checkpoint. Finally, PNUTS depletion sensitizes the tumor cell response to Aurora inhibition, suggesting that PNUTS is a potential drug target in combination anticancer therapy. IMPLICATIONS: Delineation of how PNUTS governs the mitotic activation and function of Aurora kinases will improve the understanding of the complex phospho-regulation in mitotic progression, and suggest new options to enhance the therapeutic efficacy of Aurora inhibitors.
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Affiliation(s)
- Feifei Wang
- Institute of Physical Science and Information Technology, Anhui University, Hefei, China.,Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Lincoln, Nebraska.,Institute of Hypertension, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Ling Wang
- Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Lincoln, Nebraska
| | - Laura A Fisher
- Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Lincoln, Nebraska
| | - Chunling Li
- Institute of Hypertension, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Weidong Wang
- Institute of Hypertension, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Aimin Peng
- Department of Oral Biology, College of Dentistry, University of Nebraska Medical Center, Lincoln, Nebraska.
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22
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Winkler C, Rouget R, Wu D, Beullens M, Van Eynde A, Bollen M. Overexpression of PP1-NIPP1 limits the capacity of cells to repair DNA double-strand breaks. J Cell Sci 2018; 131:jcs.214932. [PMID: 29898919 DOI: 10.1242/jcs.214932] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 05/29/2018] [Indexed: 12/20/2022] Open
Abstract
The ubiquitously expressed nuclear protein NIPP1 (also known as PPP1R8) recruits phosphoproteins for regulated dephosphorylation by the associated protein phosphatase PP1. To bypass the PP1 titration artifacts seen upon NIPP1 overexpression, we have engineered covalently linked fusions of PP1 and NIPP1, and demonstrate their potential to selectively explore the function of the PP1:NIPP1 holoenzyme. By using inducible stable cell lines, we show that PP1-NIPP1 fusions cause replication stress in a manner that requires both PP1 activity and substrate recruitment via the ForkHead Associated domain of NIPP1. More specifically, PP1-NIPP1 expression resulted in the build up of RNA-DNA hybrids (R-loops), enhanced chromatin compaction and a diminished repair of DNA double-strand breaks (DSBs), culminating in the accumulation of DSBs. These effects were associated with a reduced expression of DNA damage signaling and repair proteins. Our data disclose a key role for dephosphorylation of PP1:NIPP1 substrates in setting the threshold for DNA repair, and indicate that activators of this phosphatase hold therapeutic potential as sensitizers for DNA-damaging agents.
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Affiliation(s)
- Claudia Winkler
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium
| | - Raphael Rouget
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium
| | - Dan Wu
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium
| | - Monique Beullens
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium
| | - Aleyde Van Eynde
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium
| | - Mathieu Bollen
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium
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