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Meng Y, Li S, Lu D, Chen X, Li L, Duan Y, Wang G, Huang W, Liu R. Salt-inducible kinase 2 confers radioresistance in colorectal cancer by facilitating homologous recombination repair. MedComm (Beijing) 2025; 6:e70083. [PMID: 39877288 PMCID: PMC11774237 DOI: 10.1002/mco2.70083] [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: 05/22/2024] [Revised: 10/22/2024] [Accepted: 11/14/2024] [Indexed: 01/31/2025] Open
Abstract
Resistance to radiotherapy remains a critical barrier in treating colorectal cancer (CRC), particularly in cases of locally advanced rectal cancer (LARC). To identify key kinases involved in CRC radioresistance, we employed a kinase-targeted CRISPR-Cas9 library screen. This approach aimed to identify potential kinase inhibitors as radiosensitizers. Our screening identified salt-inducible kinase 2 (SIK2) as a critical factor in CRC radioresistance. Increased SIK2 expression correlated with reduced tumor regression and poorer outcomes in LARC patients undergoing neoadjuvant chemoradiotherapy. The depletion of SIK2 significantly enhanced radiation-induced apoptosis and tumor regression. Mechanistically, SIK2 interacts with valosin-containing protein (VCP), promoting its hyperphosphorylation. This modification improves VCP's capacity to extract K48-linked ubiquitin-conjugated proteins from chromatin, thus aiding the recruitment of RPA and RAD51 to DNA damage sites. This mechanism strengthens homologous recombination-mediated DNA repair, which contributes to radioresistance. Importantly, ARN-3236, a SIK2 inhibitor, markedly sensitized CRC cells to radiation both in vivo and in vitro, providing a potential strategy to overcome radioresistance. In summary, our findings reveal a novel mechanism by which SIK2 contributes to the radioresistance of CRC, proposing SIK2 as a potential therapeutic target with its inhibitor significantly enhancing CRC radiotherapy efficacy.
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Affiliation(s)
- Yuan Meng
- State Key Laboratory of Oncology in South ChinaGuangdong Provincial Clinical Research Center for CancerSun Yat‐sen University Cancer CenterGuangzhouChina
| | - Shuo Li
- State Key Laboratory of Oncology in South ChinaGuangdong Provincial Clinical Research Center for CancerSun Yat‐sen University Cancer CenterGuangzhouChina
- Department of PathologySun Yat‐sen University Cancer CenterGuangzhouChina
| | - Da‐Shan Lu
- State Key Laboratory of Oncology in South ChinaGuangdong Provincial Clinical Research Center for CancerSun Yat‐sen University Cancer CenterGuangzhouChina
| | - Xue Chen
- State Key Laboratory of Oncology in South ChinaGuangdong Provincial Clinical Research Center for CancerSun Yat‐sen University Cancer CenterGuangzhouChina
| | - Lu Li
- State Key Laboratory of Oncology in South ChinaGuangdong Provincial Clinical Research Center for CancerSun Yat‐sen University Cancer CenterGuangzhouChina
| | - You‐fa Duan
- State Key Laboratory of Oncology in South ChinaGuangdong Provincial Clinical Research Center for CancerSun Yat‐sen University Cancer CenterGuangzhouChina
| | - Gao‐yuan Wang
- State Key Laboratory of Oncology in South ChinaGuangdong Provincial Clinical Research Center for CancerSun Yat‐sen University Cancer CenterGuangzhouChina
| | - Wenlin Huang
- State Key Laboratory of Oncology in South ChinaGuangdong Provincial Clinical Research Center for CancerSun Yat‐sen University Cancer CenterGuangzhouChina
- Guangdong Provincial Key Laboratory of Tumor Targeted Drugs & Guangzhou Enterprise Key Laboratory of Gene MedicineGuangzhou DoublleBioproduct Co., Ltd.GuangzhouChina
| | - Ran‐yi Liu
- State Key Laboratory of Oncology in South ChinaGuangdong Provincial Clinical Research Center for CancerSun Yat‐sen University Cancer CenterGuangzhouChina
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2
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Mannar D, Ahmed S, Subramaniam S. AAA ATPase protein-protein interactions as therapeutic targets in cancer. Curr Opin Cell Biol 2024; 86:102291. [PMID: 38056141 DOI: 10.1016/j.ceb.2023.102291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 10/30/2023] [Accepted: 11/09/2023] [Indexed: 12/08/2023]
Abstract
AAA ATPases are a conserved group of enzymes that couple ATP hydrolysis to diverse activities critical for cellular homeostasis by targeted protein-protein interactions. Some of these interactions are potential therapeutic targets because of their role in cancers which rely on increased AAA ATPase activities for maintenance of genomic stability. Two well-characterized members of this family are p97/VCP and RUVBL ATPases where there is a growing understanding of their structure and function, as well as an emerging landscape of selective inhibitors. Here we highlight recent progress in this field, with particular emphasis on structural advances enabled by cryo-electron microscopy (cryo-EM).
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Affiliation(s)
- Dhiraj Mannar
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Sana Ahmed
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Sriram Subramaniam
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada; Gandeeva Therapeutics, Inc., Burnaby, BC V5C 6N5, Canada.
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3
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Ghouil R, Miron S, Sato K, Ristic D, van Rossum-Fikkert SE, Legrand P, Ouldali M, Winter JM, Ropars V, David G, Arteni AA, Wyman C, Knipscheer P, Kanaar R, Zelensky AN, Zinn-Justin S. BRCA2-HSF2BP oligomeric ring disassembly by BRME1 promotes homologous recombination. SCIENCE ADVANCES 2023; 9:eadi7352. [PMID: 37889963 PMCID: PMC10610910 DOI: 10.1126/sciadv.adi7352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 09/20/2023] [Indexed: 10/29/2023]
Abstract
In meiotic homologous recombination (HR), BRCA2 facilitates loading of the recombinases RAD51 and DMC1 at the sites of double-strand breaks (DSBs). The HSF2BP-BRME1 complex interacts with BRCA2. Its absence causes a severe reduction in recombinase loading at meiotic DSB. We previously showed that, in somatic cancer cells ectopically producing HSF2BP, DNA damage can trigger HSF2BP-dependent degradation of BRCA2, which prevents HR. Here, we report that, upon binding to BRCA2, HSF2BP forms octameric rings that are able to interlock into a large ring-shaped 24-mer. Addition of BRME1 leads to dissociation of both of these ring structures and cancels the disruptive effect of HSF2BP on cancer cell resistance to DNA damage. It also prevents BRCA2 degradation during interstrand DNA crosslink repair in Xenopus egg extracts. We propose that, during meiosis, the control of HSF2BPBRCA2 oligomerization by BRME1 ensures timely assembly of the ring complex that concentrates BRCA2 and controls its turnover, thus promoting HR.
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Affiliation(s)
- Rania Ghouil
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Simona Miron
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Koichi Sato
- Oncode Institute, Hubrecht Institute–KNAW and University Medical Center Utrecht, Utrecht, Netherlands
| | - Dejan Ristic
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, 3000 CA, Rotterdam, Netherlands
| | - Sari E. van Rossum-Fikkert
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, 3000 CA, Rotterdam, Netherlands
| | - Pierre Legrand
- Synchrotron SOLEIL, HelioBio group, L’Orme des Merisiers, Gif sur-Yvette, France
| | - Malika Ouldali
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | | | - Virginie Ropars
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Gabriel David
- Synchrotron SOLEIL, HelioBio group, L’Orme des Merisiers, Gif sur-Yvette, France
| | - Ana-Andreea Arteni
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Claire Wyman
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, 3000 CA, Rotterdam, Netherlands
- Department of Radiation Oncology, Erasmus MC Cancer Institute, Erasmus University Medical Center, 3000 CA, Rotterdam, Netherlands
| | - Puck Knipscheer
- Oncode Institute, Hubrecht Institute–KNAW and University Medical Center Utrecht, Utrecht, Netherlands
- Department of Human Genetics, Leiden University Medical Center, Leiden, Netherlands
| | - Roland Kanaar
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, 3000 CA, Rotterdam, Netherlands
| | - Alex N. Zelensky
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, 3000 CA, Rotterdam, Netherlands
| | - Sophie Zinn-Justin
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
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4
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Phospho-Ser 784-VCP Drives Resistance of Pancreatic Ductal Adenocarcinoma to Genotoxic Chemotherapies and Predicts the Chemo-Sensitizing Effect of VCP Inhibitor. Cancers (Basel) 2021; 13:cancers13205076. [PMID: 34680224 PMCID: PMC8534018 DOI: 10.3390/cancers13205076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 10/05/2021] [Accepted: 10/07/2021] [Indexed: 11/17/2022] Open
Abstract
Pancreatic ductal adenocarcinoma (PDAC) patients have a dismal prognosis due in large part to chemotherapy resistance. However, a small subset containing defects in the DNA damage response (DDR) pathways are chemotherapy-sensitive. Identifying intrinsic and therapeutically inducible DDR defects can improve precision and efficacy of chemotherapies for PDAC. DNA repair requires dynamic reorganization of chromatin-associated proteins, which is orchestrated by the AAA+ ATPase VCP. We recently discovered that the DDR function of VCP is selectively activated by Ser784 phosphorylation. In this paper, we show that pSer784-VCP but not total VCP levels in primary PDAC tumors negatively correlate with patient survival. In PDAC cell lines, different pSer784-VCP levels are induced by genotoxic chemotherapy agents and positively correlate with genome stability and cell survival. Causal effects of pSer784-VCP on DNA repair and cell survival were confirmed using VCP knockdown and functional rescue. Importantly, DNA damage-induced pSer784-VCP rather than total VCP levels in PDAC cell lines predict their chemotherapy response and chemo-sensitizing ability of selective VCP inhibitor NMS-873. Therefore, pSer784-VCP drives genotoxic chemotherapy resistance of PDAC, and can potentially be used as a predictive biomarker as well as a sensitizing target to enhance the chemotherapy response of PDAC.
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Wall JM, Basu A, Zunica ERM, Dubuisson OS, Pergola K, Broussard JP, Kirwan JP, Axelrod CL, Johnson AE. CRISPR/Cas9-engineered Drosophila knock-in models to study VCP diseases. Dis Model Mech 2021; 14:dmm048603. [PMID: 34160014 PMCID: PMC8325010 DOI: 10.1242/dmm.048603] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Accepted: 06/11/2021] [Indexed: 01/08/2023] Open
Abstract
Mutations in Valosin Containing Protein (VCP) are associated with several degenerative diseases, including multisystem proteinopathy (MSP-1) and amyotrophic lateral sclerosis. However, patients with VCP mutations vary widely in their pathology and clinical penetrance, making it difficult to devise effective treatment strategies. A deeper understanding of how each mutation affects VCP function could enhance the prediction of clinical outcomes and design of personalized treatment options. The power of a genetically tractable model organism coupled with well-established in vivo assays and a relatively short life cycle make Drosophila an attractive system to study VCP disease pathogenesis. Using CRISPR/Cas9, we have generated individual Drosophila knock-in mutants that include nine hereditary VCP disease mutations. Our models display many hallmarks of VCP-mediated degeneration, including progressive decline in mobility, protein aggregate accumulation and defects in lysosomal and mitochondrial function. We also made some novel and unexpected findings, including nuclear morphology defects and sex-specific phenotypic differences in several mutants. Taken together, the Drosophila VCP disease models generated in this study will be useful for studying the etiology of individual VCP patient mutations and testing potential genetic and/or pharmacological therapies.
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Affiliation(s)
- Jordan M. Wall
- Louisiana State University, Department of Biological Sciences, Baton Rouge, LA 70803, USA
| | - Ankita Basu
- Louisiana State University, Department of Biological Sciences, Baton Rouge, LA 70803, USA
| | - Elizabeth R. M. Zunica
- Integrated Physiology and Molecular Medicine Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA
| | - Olga S. Dubuisson
- Louisiana State University, Department of Biological Sciences, Baton Rouge, LA 70803, USA
| | - Kathryn Pergola
- Integrated Physiology and Molecular Medicine Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA
- Department of Translational Services, Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA
| | - Joshua P. Broussard
- Louisiana State University, Department of Biological Sciences, Baton Rouge, LA 70803, USA
| | - John P. Kirwan
- Integrated Physiology and Molecular Medicine Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA
| | - Christopher L. Axelrod
- Integrated Physiology and Molecular Medicine Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA
- Department of Translational Services, Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA
| | - Alyssa E. Johnson
- Louisiana State University, Department of Biological Sciences, Baton Rouge, LA 70803, USA
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Garrison P, Bangs JD. p97 Inhibitor CB-5083 Blocks ERAD in Trypanosoma brucei. Mol Biochem Parasitol 2020; 239:111313. [PMID: 32735998 DOI: 10.1016/j.molbiopara.2020.111313] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 07/22/2020] [Accepted: 07/23/2020] [Indexed: 11/26/2022]
Abstract
Misfolded proteins trapped in the endoplasmic reticulum (ER) are specifically recognized and retrotranslocated to the cytosol by the ER-Associated Degradation (ERAD) system and delivered to the proteasome for destruction. This process was recently described in Trypanosoma brucei (T. brucei) using the misfolded epitope tagged Transferrin Receptor subunits ESAG7:Ty and HA:ESAG6 (HA:E6). Critical to this work was the proteasomal inhibitor MG132. However, MG132 has off-target inhibitory effects on lysosomal Cathepsin L that could cause misinterpretation of turnover results. Here, we evaluate an orally bioavailable p97 inhibitor, CB-5083, for use in T. brucei. p97 is a ubiquitous protein involved in many cellular events including the membrane extraction step of ERAD. CB-5083 strongly inhibits turnover of HA:E6, with comparable protein recovery to MG132 treatment. Interestingly, little deglycosylated cytoplasmic species accumulates, though it normally emerges with MG132 treatment. This suggests that CB-5083 blocks ERAD upstream of the proteasome, as expected for inhibition of the trypanosomal p97 orthologue TbVCP. Under CB-5083 treatment, HA:E6 is also strongly membrane-associated, suggesting ER localization. Finally, we provide an experimental example where CB-5083 treatment offers clarity to the off-target effects of MG132 treatment.
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Affiliation(s)
- Paige Garrison
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo (SUNY), Buffalo, NY, 14203, USA
| | - James D Bangs
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo (SUNY), Buffalo, NY, 14203, USA.
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7
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Regulation of Histone Ubiquitination in Response to DNA Double Strand Breaks. Cells 2020; 9:cells9071699. [PMID: 32708614 PMCID: PMC7407225 DOI: 10.3390/cells9071699] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 07/10/2020] [Accepted: 07/14/2020] [Indexed: 12/11/2022] Open
Abstract
Eukaryotic cells are constantly exposed to both endogenous and exogenous stressors that promote the induction of DNA damage. Of this damage, double strand breaks (DSBs) are the most lethal and must be efficiently repaired in order to maintain genomic integrity. Repair of DSBs occurs primarily through one of two major pathways: non-homologous end joining (NHEJ) or homologous recombination (HR). The choice between these pathways is in part regulated by histone post-translational modifications (PTMs) including ubiquitination. Ubiquitinated histones not only influence transcription and chromatin architecture at sites neighboring DSBs but serve as critical recruitment platforms for repair machinery as well. The reversal of these modifications by deubiquitinating enzymes (DUBs) is increasingly being recognized in a number of cellular processes including DSB repair. In this context, DUBs ensure proper levels of ubiquitin, regulate recruitment of downstream effectors, dictate repair pathway choice, and facilitate appropriate termination of the repair response. This review outlines the current understanding of histone ubiquitination in response to DSBs, followed by a comprehensive overview of the DUBs that catalyze the removal of these marks.
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8
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Majera D, Skrott Z, Chroma K, Merchut-Maya JM, Mistrik M, Bartek J. Targeting the NPL4 Adaptor of p97/VCP Segregase by Disulfiram as an Emerging Cancer Vulnerability Evokes Replication Stress and DNA Damage while Silencing the ATR Pathway. Cells 2020; 9:cells9020469. [PMID: 32085572 PMCID: PMC7072750 DOI: 10.3390/cells9020469] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 02/17/2020] [Accepted: 02/17/2020] [Indexed: 12/20/2022] Open
Abstract
Research on repurposing the old alcohol-aversion drug disulfiram (DSF) for cancer treatment has identified inhibition of NPL4, an adaptor of the p97/VCP segregase essential for turnover of proteins involved in multiple pathways, as an unsuspected cancer cell vulnerability. While we reported that NPL4 is targeted by the anticancer metabolite of DSF, the bis-diethyldithiocarbamate-copper complex (CuET), the exact, apparently multifaceted mechanism(s) through which the CuET-induced aggregation of NPL4 kills cancer cells remains to be fully elucidated. Given the pronounced sensitivity to CuET in tumor cell lines lacking the genome integrity caretaker proteins BRCA1 and BRCA2, here we investigated the impact of NPL4 targeting by CuET on DNA replication dynamics and DNA damage response pathways in human cancer cell models. Our results show that CuET treatment interferes with DNA replication, slows down replication fork progression and causes accumulation of single-stranded DNA (ssDNA). Such a replication stress (RS) scenario is associated with DNA damage, preferentially in the S phase, and activates the homologous recombination (HR) DNA repair pathway. At the same time, we find that cellular responses to the CuET-triggered RS are seriously impaired due to concomitant malfunction of the ATRIP-ATR-CHK1 signaling pathway that reflects an unorthodox checkpoint silencing mode through ATR (Ataxia telangiectasia and Rad3 related) kinase sequestration within the CuET-evoked NPL4 protein aggregates.
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Affiliation(s)
- Dusana Majera
- Laboratory of Genome Integrity, Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, 77 147 Olomouc, Czech Republic
| | - Zdenek Skrott
- Laboratory of Genome Integrity, Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, 77 147 Olomouc, Czech Republic
| | - Katarina Chroma
- Laboratory of Genome Integrity, Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, 77 147 Olomouc, Czech Republic
| | | | - Martin Mistrik
- Laboratory of Genome Integrity, Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, 77 147 Olomouc, Czech Republic
- Correspondence: (M.M.); (J.B.)
| | - Jiri Bartek
- Laboratory of Genome Integrity, Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, 77 147 Olomouc, Czech Republic
- Danish Cancer Society Research Center, 2100 Copenhagen, Denmark
- Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Science for Life Laboratory, Karolinska Institute, 171 77 Stockholm, Sweden
- Correspondence: (M.M.); (J.B.)
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9
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Singh AN, Oehler J, Torrecilla I, Kilgas S, Li S, Vaz B, Guérillon C, Fielden J, Hernandez‐Carralero E, Cabrera E, Tullis IDC, Meerang M, Barber PR, Freire R, Parsons J, Vojnovic B, Kiltie AE, Mailand N, Ramadan K. The p97-Ataxin 3 complex regulates homeostasis of the DNA damage response E3 ubiquitin ligase RNF8. EMBO J 2019; 38:e102361. [PMID: 31613024 PMCID: PMC6826192 DOI: 10.15252/embj.2019102361] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 09/16/2019] [Accepted: 09/19/2019] [Indexed: 12/31/2022] Open
Abstract
The E3 ubiquitin ligase RNF8 (RING finger protein 8) is a pivotal enzyme for DNA repair. However, RNF8 hyper-accumulation is tumour-promoting and positively correlates with genome instability, cancer cell invasion, metastasis and poor patient prognosis. Very little is known about the mechanisms regulating RNF8 homeostasis to preserve genome stability. Here, we identify the cellular machinery, composed of the p97/VCP ubiquitin-dependent unfoldase/segregase and the Ataxin 3 (ATX3) deubiquitinase, which together form a physical and functional complex with RNF8 to regulate its proteasome-dependent homeostasis under physiological conditions. Under genotoxic stress, when RNF8 is rapidly recruited to sites of DNA lesions, the p97-ATX3 machinery stimulates the extraction of RNF8 from chromatin to balance DNA repair pathway choice and promote cell survival after ionising radiation (IR). Inactivation of the p97-ATX3 complex affects the non-homologous end joining DNA repair pathway and hypersensitises human cancer cells to IR. We propose that the p97-ATX3 complex is the essential machinery for regulation of RNF8 homeostasis under both physiological and genotoxic conditions and that targeting ATX3 may be a promising strategy to radio-sensitise BRCA-deficient cancers.
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Affiliation(s)
- Abhay Narayan Singh
- Department of OncologyCancer Research UK/Medical Research Council Oxford Institute for Radiation OncologyUniversity of OxfordOxfordUK
| | - Judith Oehler
- Department of OncologyCancer Research UK/Medical Research Council Oxford Institute for Radiation OncologyUniversity of OxfordOxfordUK
- Present address:
Department of BiochemistryUniversity of OxfordOxfordUK
| | - Ignacio Torrecilla
- Department of OncologyCancer Research UK/Medical Research Council Oxford Institute for Radiation OncologyUniversity of OxfordOxfordUK
| | - Susan Kilgas
- Department of OncologyCancer Research UK/Medical Research Council Oxford Institute for Radiation OncologyUniversity of OxfordOxfordUK
| | - Shudong Li
- Department of OncologyCancer Research UK/Medical Research Council Oxford Institute for Radiation OncologyUniversity of OxfordOxfordUK
| | - Bruno Vaz
- Department of OncologyCancer Research UK/Medical Research Council Oxford Institute for Radiation OncologyUniversity of OxfordOxfordUK
| | - Claire Guérillon
- Novo Nordisk Foundation Center for Protein ResearchUniversity of CopenhagenCopenhagenDenmark
| | - John Fielden
- Department of OncologyCancer Research UK/Medical Research Council Oxford Institute for Radiation OncologyUniversity of OxfordOxfordUK
| | - Esperanza Hernandez‐Carralero
- Unidad de InvestigaciónHospital Universitario de CanariasLa LagunaSpain
- Instituto de Tecnologías BiomédicasUniversidad de La LagunaLa LagunaSpain
| | - Elisa Cabrera
- Unidad de InvestigaciónHospital Universitario de CanariasLa LagunaSpain
- Instituto de Tecnologías BiomédicasUniversidad de La LagunaLa LagunaSpain
| | - Iain DC Tullis
- Department of OncologyCancer Research UK/Medical Research Council Oxford Institute for Radiation OncologyUniversity of OxfordOxfordUK
| | - Mayura Meerang
- Institute of Pharmacology and Toxicology‐Vetsuisse FacultyUniversity of ZurichZurichSwitzerland
- Present address:
Department of Thoracic SurgeryUniversity Hospital ZurichZurichSwitzerland
| | - Paul R Barber
- Department of OncologyCancer Research UK/Medical Research Council Oxford Institute for Radiation OncologyUniversity of OxfordOxfordUK
| | - Raimundo Freire
- Unidad de InvestigaciónHospital Universitario de CanariasLa LagunaSpain
- Instituto de Tecnologías BiomédicasUniversidad de La LagunaLa LagunaSpain
- Universidad Fernando Pessoa CanariasSanta Maria de GuiaSpain
| | - Jason Parsons
- Department of Molecular and Clinical Cancer MedicineCancer Research CentreUniversity of LiverpoolLiverpoolUK
| | - Borivoj Vojnovic
- Department of OncologyCancer Research UK/Medical Research Council Oxford Institute for Radiation OncologyUniversity of OxfordOxfordUK
| | - Anne E Kiltie
- Department of OncologyCancer Research UK/Medical Research Council Oxford Institute for Radiation OncologyUniversity of OxfordOxfordUK
| | - Niels Mailand
- Novo Nordisk Foundation Center for Protein ResearchUniversity of CopenhagenCopenhagenDenmark
| | - Kristijan Ramadan
- Department of OncologyCancer Research UK/Medical Research Council Oxford Institute for Radiation OncologyUniversity of OxfordOxfordUK
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10
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Ali MAM, Strickfaden H, Lee BL, Spyracopoulos L, Hendzel MJ. RYBP Is a K63-Ubiquitin-Chain-Binding Protein that Inhibits Homologous Recombination Repair. Cell Rep 2019; 22:383-395. [PMID: 29320735 DOI: 10.1016/j.celrep.2017.12.047] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 11/07/2017] [Accepted: 12/13/2017] [Indexed: 12/14/2022] Open
Abstract
Ring1-YY1-binding protein (RYBP) is a member of the non-canonical polycomb repressive complex 1 (PRC1), and like other PRC1 members, it is best described as a transcriptional regulator. However, several PRC1 members were recently shown to function in DNA repair. Here, we report that RYBP preferentially binds K63-ubiquitin chains via its Npl4 zinc finger (NZF) domain. Since K63-linked ubiquitin chains are assembled at DNA double-strand breaks (DSBs), we examined the contribution of RYBP to DSB repair. Surprisingly, we find that RYBP is K48 polyubiquitylated by RNF8 and rapidly removed from chromatin upon DNA damage by the VCP/p97 segregase. High expression of RYBP competitively inhibits recruitment of BRCA1 repair complex to DSBs, reducing DNA end resection and homologous recombination (HR) repair. Moreover, breast cancer cell lines expressing high endogenous RYBP levels show increased sensitivity to DNA-damaging agents and poly ADP-ribose polymerase (PARP) inhibition. These data suggest that RYBP negatively regulates HR repair by competing for K63-ubiquitin chain binding.
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Affiliation(s)
- Mohammad A M Ali
- Department of Oncology, Faculty of Medicine and Dentistry, University of Alberta, 11560 University Avenue, Edmonton, AB T6G 2H7, Canada
| | - Hilmar Strickfaden
- Department of Oncology, Faculty of Medicine and Dentistry, University of Alberta, 11560 University Avenue, Edmonton, AB T6G 2H7, Canada
| | - Brian L Lee
- Department of Biochemistry, Faculty of Medicine and Dentistry, University of Alberta, 11560 University Avenue, Edmonton, AB T6G 2H7, Canada
| | - Leo Spyracopoulos
- Department of Biochemistry, Faculty of Medicine and Dentistry, University of Alberta, 11560 University Avenue, Edmonton, AB T6G 2H7, Canada
| | - Michael J Hendzel
- Department of Oncology, Faculty of Medicine and Dentistry, University of Alberta, 11560 University Avenue, Edmonton, AB T6G 2H7, Canada.
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11
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Torrecilla I, Oehler J, Ramadan K. The role of ubiquitin-dependent segregase p97 (VCP or Cdc48) in chromatin dynamics after DNA double strand breaks. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0282. [PMID: 28847819 PMCID: PMC5577460 DOI: 10.1098/rstb.2016.0282] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/24/2017] [Indexed: 12/27/2022] Open
Abstract
DNA double strand breaks (DSBs) are the most cytotoxic DNA lesions and, if not repaired, lead to chromosomal rearrangement, genomic instability and cell death. Cells have evolved a complex network of DNA repair and signalling molecules which promptly detect and repair DSBs, commonly known as the DNA damage response (DDR). The DDR is orchestrated by various post-translational modifications such as phosphorylation, methylation, ubiquitination or SUMOylation. As DSBs are located in complex chromatin structures, the repair of DSBs is engineered at two levels: (i) at sites of broken DNA and (ii) at chromatin structures that surround DNA lesions. Thus, DNA repair and chromatin remodelling machineries must work together to efficiently repair DSBs. Here, we summarize the current knowledge of the ubiquitin-dependent molecular unfoldase/segregase p97 (VCP in vertebrates and Cdc48 in worms and lower eukaryotes) in DSB repair. We identify p97 as an essential factor that regulates DSB repair. p97-dependent extraction of ubiquitinated substrates mediates spatio-temporal protein turnover at and around the sites of DSBs, thus orchestrating chromatin remodelling and DSB repair. As p97 is a druggable target, p97 inhibition in the context of DDR has great potential for cancer therapy, as shown for other DDR components such as PARP, ATR and CHK1.This article is part of the themed issue 'Chromatin modifiers and remodellers in DNA repair and signalling'.
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Affiliation(s)
- Ignacio Torrecilla
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Judith Oehler
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Kristijan Ramadan
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Roosevelt Drive, Oxford OX3 7DQ, UK
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Baranes-Bachar K, Levy-Barda A, Oehler J, Reid DA, Soria-Bretones I, Voss TC, Chung D, Park Y, Liu C, Yoon JB, Li W, Dellaire G, Misteli T, Huertas P, Rothenberg E, Ramadan K, Ziv Y, Shiloh Y. The Ubiquitin E3/E4 Ligase UBE4A Adjusts Protein Ubiquitylation and Accumulation at Sites of DNA Damage, Facilitating Double-Strand Break Repair. Mol Cell 2018; 69:866-878.e7. [PMID: 29499138 PMCID: PMC6265044 DOI: 10.1016/j.molcel.2018.02.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2016] [Revised: 12/12/2017] [Accepted: 01/31/2018] [Indexed: 11/18/2022]
Abstract
Double-strand breaks (DSBs) are critical DNA lesions that robustly activate the elaborate DNA damage response (DDR) network. We identified a critical player in DDR fine-tuning: the E3/E4 ubiquitin ligase UBE4A. UBE4A's recruitment to sites of DNA damage is dependent on primary E3 ligases in the DDR and promotes enhancement and sustainment of K48- and K63-linked ubiquitin chains at these sites. This step is required for timely recruitment of the RAP80 and BRCA1 proteins and proper organization of RAP80- and BRCA1-associated protein complexes at DSB sites. This pathway is essential for optimal end resection at DSBs, and its abrogation leads to upregulation of the highly mutagenic alternative end-joining repair at the expense of error-free homologous recombination repair. Our data uncover a critical regulatory level in the DSB response and underscore the importance of fine-tuning the complex DDR network for accurate and balanced execution of DSB repair.
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Affiliation(s)
- Keren Baranes-Bachar
- The David and Inez Myers Laboratory for Cancer Research, Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Adva Levy-Barda
- The David and Inez Myers Laboratory for Cancer Research, Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Judith Oehler
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, UK
| | - Dylan A Reid
- Perlmutter NYU Cancer Center and Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, USA
| | - Isabel Soria-Bretones
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER) and Department of Genetics, University of Sevilla, Sevilla, Spain
| | - Ty C Voss
- National Cancer Institute, NIH, Bethesda, MD, USA
| | - Dudley Chung
- Departments of Pathology and Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS, Canada
| | - Yoon Park
- Department of Biochemistry and Protein Network Research Center, Yonsei University, 134 Shinchon-Dong, Seodaemoon-Gu, Seoul, Korea
| | - Chao Liu
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Jong-Bok Yoon
- Department of Biochemistry and Protein Network Research Center, Yonsei University, 134 Shinchon-Dong, Seodaemoon-Gu, Seoul, Korea
| | - Wei Li
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Graham Dellaire
- Departments of Pathology and Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS, Canada
| | - Tom Misteli
- National Cancer Institute, NIH, Bethesda, MD, USA
| | - Pablo Huertas
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER) and Department of Genetics, University of Sevilla, Sevilla, Spain
| | - Eli Rothenberg
- Perlmutter NYU Cancer Center and Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, USA
| | - Kristijan Ramadan
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, UK
| | - Yael Ziv
- The David and Inez Myers Laboratory for Cancer Research, Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Yosef Shiloh
- The David and Inez Myers Laboratory for Cancer Research, Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
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Lee BL, Singh A, Mark Glover JN, Hendzel MJ, Spyracopoulos L. Molecular Basis for K63-Linked Ubiquitination Processes in Double-Strand DNA Break Repair: A Focus on Kinetics and Dynamics. J Mol Biol 2017; 429:3409-3429. [PMID: 28587922 DOI: 10.1016/j.jmb.2017.05.029] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 05/20/2017] [Accepted: 05/30/2017] [Indexed: 11/18/2022]
Abstract
Cells are exposed to thousands of DNA damage events on a daily basis. This damage must be repaired to preserve genetic information and prevent development of disease. The most deleterious damage is a double-strand break (DSB), which is detected and repaired by mechanisms known as non-homologous end-joining (NHEJ) and homologous recombination (HR), which are components of the DNA damage response system. NHEJ is an error-prone first line of defense, whereas HR invokes error-free repair and is the focus of this review. The functions of the protein components of HR-driven DNA repair are regulated by the coordinated action of post-translational modifications including lysine acetylation, phosphorylation, ubiquitination, and SUMOylation. The latter two mechanisms are fundamental for recognition of DSBs and reorganizing chromatin to facilitate repair. We focus on the structures and molecular mechanisms for the protein components underlying synthesis, recognition, and cleavage of K63-linked ubiquitin chains, which are abundant at damage sites and obligatory for DSB repair. The forward flux of the K63-linked ubiquitination cascade is driven by the combined activity of E1 enzyme, the heterodimeric E2 Mms2-Ubc13, and its cognate E3 ligases RNF8 and RNF168, which is balanced through the binding and cleavage of chains by the deubiquitinase BRCC36, and the proteasome, and through the binding of chains by recognition modules on repair proteins such as RAP80. We highlight a number of aspects regarding our current understanding for the role of kinetics and dynamics in determining the function of the enzymes and chain recognition modules that drive K63 ubiquitination.
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Affiliation(s)
- Brian L Lee
- Department of Biochemistry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - Anamika Singh
- Department of Biochemistry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - J N Mark Glover
- Department of Biochemistry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - Michael J Hendzel
- Department of Oncology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada; Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - Leo Spyracopoulos
- Department of Biochemistry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada.
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p97 Promotes a Conserved Mechanism of Helicase Unloading during DNA Cross-Link Repair. Mol Cell Biol 2016; 36:2983-2994. [PMID: 27644328 DOI: 10.1128/mcb.00434-16] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 09/16/2016] [Indexed: 01/07/2023] Open
Abstract
Interstrand cross-links (ICLs) are extremely toxic DNA lesions that create an impassable roadblock to DNA replication. When a replication fork collides with an ICL, it triggers a damage response that promotes multiple DNA processing events required to excise the cross-link from chromatin and resolve the stalled replication fork. One of the first steps in this process involves displacement of the CMG replicative helicase (comprised of Cdc45, MCM2-7, and GINS), which obstructs the underlying cross-link. Here we report that the p97/Cdc48/VCP segregase plays a critical role in ICL repair by unloading the CMG complex from chromatin. Eviction of the stalled helicase involves K48-linked polyubiquitylation of MCM7, p97-mediated extraction of CMG, and a largely degradation-independent mechanism of MCM7 deubiquitylation. Our results show that ICL repair and replication termination both utilize a similar mechanism to displace the CMG complex from chromatin. However, unlike termination, repair-mediated helicase unloading involves the tumor suppressor protein BRCA1, which acts upstream of MCM7 ubiquitylation and p97 recruitment. Together, these findings indicate that p97 plays a conserved role in dismantling the CMG helicase complex during different cellular events, but that distinct regulatory signals ultimately control when and where unloading takes place.
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15
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Vij N. Nano-based rescue of dysfunctional autophagy in chronic obstructive lung diseases. Expert Opin Drug Deliv 2016; 14:483-489. [PMID: 27561233 DOI: 10.1080/17425247.2016.1223040] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
INTRODUCTION ΔF508-CFTR (cystic fibrosis transmembrane conductance regulator) is a common CF-mutation that is known to induce oxidative-inflammatory stress through activation of reactive oxygen species (ROS), which induces autophagy-impairment resulting in accumulation of CFTR in aggresome-bodies. Cysteamine, the reduced form of cystamine, is a FDA-approved drug that has anti-oxidant, anti-bacterial, and mucolytic properties. This drug has been shown in a recent clinical trial to decrease lung inflammation and improve lung function in CF patients by potentially restoring autophagy and allowing CFTR to be trafficked to the cell membrane. Areas covered: The delivery of cysteamine to airway epithelia of chronic subjects prerequisite the need for a delivery system to allow rescue of dysfunctional autophagy. Expert opinion: We anticipate based on our ongoing studies that PLGA-PEG- or Dendrimer-mediated cysteamine delivery could allow sustained airway delivery over standard cysteamine tablets or delay release capsules that are currently used for systemic treatment. In addition, proposed nano-based autophagy induction strategy can also allow rescue of cigarette smoke (CS) induced acquired-CFTR dysfunction seen in chronic obstructive pulmonary disease (COPD)-emphysema subjects. The CS induced acquired-CFTR dysfunction involves CFTR-accumulation in aggresome-bodies that can be rescued by an autophagy-inducing antioxidant drug, cysteamine. Moreover, chronic CS-exposure generates ROS that induces overall protein-misfolding and aggregation of ubiquitinated-proteins as aggresome-bodies via autophagy-impairment that can be also be resolved by treatment with autophagy-inducing antioxidant drug, cysteamine.
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Affiliation(s)
- Neeraj Vij
- a College of Medicine , Central Michigan University , Mount Pleasant , MI , USA.,b Department of Pediatric Respiratory Sciences , The Johns Hopkins School of Medicine , Baltimore , MD , USA
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Morris C, Tomimatsu N, Burma S, Jalinot P. INT6/EIF3E Controls the RNF8-Dependent Ubiquitylation Pathway and Facilitates DNA Double-Strand Break Repair in Human Cells. Cancer Res 2016; 76:6054-6065. [PMID: 27550454 DOI: 10.1158/0008-5472.can-16-0723] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 07/27/2016] [Indexed: 11/16/2022]
Abstract
Unrepaired DNA double-strand breaks (DSB) are the most destructive chromosomal lesions driving genomic instability, a core hallmark of cancer. Here, we identify the antioncogenic breast cancer factor INT6/EIF3E as an essential regulator of DSB repair that promotes homologous recombination (HR)-mediated repair and, to a lesser extent, nonhomologous end-joining repair. INT6 silencing impaired the accrual of the ubiquitin ligase RNF8 at DSBs and the formation of ubiquitin conjugates at DSB sites, especially Lys63-linked polyubiquitin chains, resulting in impaired recruitment of BRCA1, BRCA2, and RAD51, which are all involved in HR repair. In contrast, INT6 deficiency did not affect the accumulation of RNF168, 53BP1, or RPA at DSBs. In INT6-silenced cells, there was also an alteration in DNA damage-induced localization of MDC1, a key target for ATM phosphorylation, which is a prerequisite for RNF8 recruitment. The attenuated DNA damage localization of RNF8 resulting from INT6 depletion could be attributed to the defective retention of ATM previously reported by us. Our findings deepen insights into how INT6 protects against breast cancer by showing how it functions in DSB repair, with potential clinical implications for cancer therapy. Cancer Res; 76(20); 6054-65. ©2016 AACR.
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Affiliation(s)
- Christelle Morris
- Laboratory of Biology and Modelling of the Cell, CNRS UMR 5239, INSERM U1210, ENS de Lyon, University of Lyon, Lyon, France
| | - Nozomi Tomimatsu
- Division of Molecular Radiation Biology, Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Sandeep Burma
- Division of Molecular Radiation Biology, Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Pierre Jalinot
- Laboratory of Biology and Modelling of the Cell, CNRS UMR 5239, INSERM U1210, ENS de Lyon, University of Lyon, Lyon, France.
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Publisher’s Note. DNA Repair (Amst) 2016. [DOI: 10.1016/j.dnarep.2016.05.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Abstract
Nucleotide excision repair (NER) protects genome stability by eliminating DNA helix distorting lesions, such as those induced by UV radiation. The addition and removal of ubiquitin, namely, ubiquitination and deubiquitination, have recently been demonstrated as general mechanisms to regulate protein functions. Accumulating evidence shows that several NER factors are subjected to extensive regulation by ubiquitination and deubiquitination. Thus, the balance between E3 ligases and deubiquitinating enzyme activities can dynamically alter the ubiquitin landscape at DNA damage sites, thereby regulating NER efficiency. Current knowledge about XPC ubiquitination by different ubiquitin E3 ligases highlights the importance of ubiquitin linkage types in regulating XPC binding and release from damaged DNA. Here, we discuss the emerging roles of deubiquitinating enzymes and their ubiquitin linkage specificities in NER.
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19
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Fenoy IM, Bogado SS, Contreras SM, Gottifredi V, Angel SO. The Knowns Unknowns: Exploring the Homologous Recombination Repair Pathway in Toxoplasma gondii. Front Microbiol 2016; 7:627. [PMID: 27199954 PMCID: PMC4853372 DOI: 10.3389/fmicb.2016.00627] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 04/18/2016] [Indexed: 12/17/2022] Open
Abstract
Toxoplasma gondii is an apicomplexan parasite of medical and veterinary importance which causes toxoplasmosis in humans. Great effort is currently being devoted toward the identification of novel drugs capable of targeting such illness. In this context, we believe that the thorough understanding of the life cycle of this model parasite will facilitate the identification of new druggable targets in T. gondii. It is important to exploit the available knowledge of pathways which could modulate the sensitivity of the parasite to DNA damaging agents. The homologous recombination repair (HRR) pathway may be of particular interest in this regard as its inactivation sensitizes other cellular models such as human cancer to targeted therapy. Herein we discuss the information available on T. gondii's HRR pathway from the perspective of its conservation with respect to yeast and humans. Special attention was devoted to BRCT domain-containing and end-resection associated proteins in T. gondii as in other experimental models such proteins have crucial roles in early/late steps or HRR and in the pathway choice for double strand break resolution. We conclude that T. gondii HRR pathway is a source of several lines of investigation that allow to to comprehend the extent of diversification of HRR in T. gondii. Such an effort will serve to determine if HRR could represent a potential targer for the treatment of toxoplasmosis.
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Affiliation(s)
- Ignacio M Fenoy
- Laboratorio de Parasitología Molecular, IIB-INTECH, CONICET-UNSAM Chascomús, Argentina
| | - Silvina S Bogado
- Laboratorio de Parasitología Molecular, IIB-INTECH, CONICET-UNSAM Chascomús, Argentina
| | - Susana M Contreras
- Laboratorio de Parasitología Molecular, IIB-INTECH, CONICET-UNSAM Chascomús, Argentina
| | - Vanesa Gottifredi
- Cell Cycle Genomic Instability Laboratory, Fundación Instituto Leloir, IIBBA-CONICET Chascomús, Argentina
| | - Sergio O Angel
- Laboratorio de Parasitología Molecular, IIB-INTECH, CONICET-UNSAM Chascomús, Argentina
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Ramadan K, Halder S, Wiseman K, Vaz B. Strategic role of the ubiquitin-dependent segregase p97 (VCP or Cdc48) in DNA replication. Chromosoma 2016; 126:17-32. [PMID: 27086594 DOI: 10.1007/s00412-016-0587-4] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 03/10/2016] [Accepted: 03/16/2016] [Indexed: 01/01/2023]
Abstract
Genome amplification (DNA synthesis) is one of the most demanding cellular processes in all proliferative cells. The DNA replication machinery (also known as the replisome) orchestrates genome amplification during S-phase of the cell cycle. Genetic material is particularly vulnerable to various events that can challenge the replisome during its assembly, activation (firing), progression (elongation) and disassembly from chromatin (termination). Any disturbance of the replisome leads to stalling of the DNA replication fork and firing of dormant replication origins, a process known as DNA replication stress. DNA replication stress is considered to be one of the main causes of sporadic cancers and other pathologies related to tissue degeneration and ageing. The mechanisms of replisome assembly and elongation during DNA synthesis are well understood. However, once DNA synthesis is complete, the process of replisome disassembly, and its removal from chromatin, remains unclear. In recent years, a growing body of evidence has alluded to a central role in replisome regulation for the ubiquitin-dependent protein segregase p97, also known as valosin-containing protein (VCP) in metazoans and Cdc48 in lower eukaryotes. By orchestrating the spatiotemporal turnover of the replisome, p97 plays an essential role in DNA replication. In this review, we will summarise our current knowledge about how p97 controls the replisome from replication initiation, to elongation and finally termination. We will also further examine the more recent findings concerning the role of p97 and how mutations in p97 cofactors, also known as adaptors, cause DNA replication stress induced genomic instability that leads to cancer and accelerated ageing. To our knowledge, this is the first comprehensive review concerning the mechanisms involved in the regulation of DNA replication by p97.
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Affiliation(s)
- Kristijan Ramadan
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Roosevelt Drive, Oxford, OX3 7DQ, UK.
| | - Swagata Halder
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Roosevelt Drive, Oxford, OX3 7DQ, UK
| | - Katherine Wiseman
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Roosevelt Drive, Oxford, OX3 7DQ, UK
| | - Bruno Vaz
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Roosevelt Drive, Oxford, OX3 7DQ, UK
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Dantuma NP, van Attikum H. Spatiotemporal regulation of posttranslational modifications in the DNA damage response. EMBO J 2015; 35:6-23. [PMID: 26628622 DOI: 10.15252/embj.201592595] [Citation(s) in RCA: 156] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 11/06/2015] [Indexed: 11/09/2022] Open
Abstract
A timely and accurate cellular response to DNA damage requires tight regulation of the action of DNA damage response (DDR) proteins at lesions. A multitude of posttranslational modifications (PTMs) of chromatin and chromatin-associated proteins coordinates the recruitment of critical proteins that dictate the appropriate DNA repair pathway and enable the actual repair of lesions. Phosphorylation, ubiquitylation, SUMOylation, neddylation, poly(ADP-ribosyl)ation, acetylation, and methylation are among the DNA damage-induced PTMs that have taken center stage as important DDR regulators. Redundant and multivalent interactions of DDR proteins with PTMs may not only be a means to facilitate efficient relocalization, but also a feature that allows high temporal and spatial resolution of protein recruitment to, and extraction from, DNA damage sites. In this review, we will focus on the complex interplay between such PTMs, and discuss the importance of their interconnectivity in coding DNA lesions and maintaining the integrity of the genome.
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Affiliation(s)
- Nico P Dantuma
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Haico van Attikum
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
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Grigoreva TA, Tribulovich VG, Garabadzhiu AV, Melino G, Barlev NA. The 26S proteasome is a multifaceted target for anti-cancer therapies. Oncotarget 2015; 6:24733-49. [PMID: 26295307 PMCID: PMC4694792 DOI: 10.18632/oncotarget.4619] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2015] [Accepted: 07/10/2015] [Indexed: 12/30/2022] Open
Abstract
Proteasomes play a critical role in the fate of proteins that are involved in major cellular processes, including signal transduction, gene expression, cell cycle, replication, differentiation, immune response, cellular response to stress, etc. In contrast to non-specific degradation by lysosomes, proteasomes are highly selective and destroy only the proteins that are covalently labelled with small proteins, called ubiquitins. Importantly, many diseases, including neurodegenerative diseases and cancers, are intimately connected to the activity of proteasomes making them an important pharmacological target. Currently, the vast majority of inhibitors are aimed at blunting the proteolytic activities of proteasomes. However, recent achievements in solving structures of proteasomes at very high resolution provided opportunities to design new classes of small molecules that target other physiologically-important enzymatic activities of proteasomes, including the de-ubiquitinating one. This review attempts to catalog the information available to date about novel classes of proteasome inhibitors that may have important pharmacological ramifications.
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Affiliation(s)
- Tatyana A Grigoreva
- St. Petersburg State Technological Institute (Technical University), St. Petersburng, Russia
| | | | | | - Gerry Melino
- St. Petersburg State Technological Institute (Technical University), St. Petersburng, Russia
- University of Rome Tor Vergata, Roma, Italy
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23
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Nadeau MÈ, Rico C, Tsoi M, Vivancos M, Filimon S, Paquet M, Boerboom D. Pharmacological targeting of valosin containing protein (VCP) induces DNA damage and selectively kills canine lymphoma cells. BMC Cancer 2015; 15:479. [PMID: 26104798 PMCID: PMC4479320 DOI: 10.1186/s12885-015-1489-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Accepted: 06/14/2015] [Indexed: 12/20/2022] Open
Abstract
Background Valosin containing protein (VCP) is a critical mediator of protein homeostasis and may represent a valuable therapeutic target for several forms of cancer. Overexpression of VCP occurs in many cancers, and often in a manner correlating with malignancy and poor outcome. Here, we analyzed VCP expression in canine lymphoma and assessed its potential as a therapeutic target for this disease. Methods VCP expression in canine lymphomas was evaluated by immunoblotting and immunohistochemistry. The canine lymphoma cell lines CLBL-1, 17–71 and CL-1 were treated with the VCP inhibitor Eeyarestatin 1 (EER-1) at varying concentrations and times and were assessed for viability by trypan blue exclusion, apoptosis by TUNEL and caspase activity assays, and proliferation by propidium iodide incorporation and FACS. The mechanism of EER-1 action was determined by immunoblotting and immunofluorescence analyses of Lys48 ubiquitin and markers of ER stress (DDIT3), autophagy (SQSTM1, MAP1LC3A) and DNA damage (γH2AFX). TRP53/ATM-dependent signaling pathway activity was assessed by immunoblotting for TRP53 and phospho-TRP53 and real-time RT-PCR measurement of Cdkn1a mRNA. Results VCP expression levels in canine B cell lymphomas were found to increase with grade. EER-1 treatment killed canine lymphoma cells preferentially over control peripheral blood mononuclear cells. EER-1 treatment of CLBL-1 cells was found to both induce apoptosis and cell cycle arrest in G1. Unexpectedly, EER-1 did not appear to act either by inducing ER stress or inhibiting the aggresome-autophagy pathway. Rather, a rapid and dramatic increase in γH2AFX expression was noted, indicating that EER-1 may act by promoting DNA damage accumulation. Increased TRP53 phosphorylation and Cdkn1a mRNA levels indicated an activation of the TRP53/ATM DNA damage response pathway in response to EER-1, likely contributing to the induction of apoptosis and cell cycle arrest. Conclusions These results correlate VCP expression with malignancy in canine B cell lymphoma. The selective activity of EER-1 against lymphoma cells suggests that VCP will represent a clinically useful therapeutic target for the treatment of lymphoma. We further suggest a mechanism of EER-1 action centered on the DNA repair response that may be of central importance for the design and characterization of VCP inhibitory compounds for therapeutic use. Electronic supplementary material The online version of this article (doi:10.1186/s12885-015-1489-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Marie-Ève Nadeau
- Département des Sciences Cliniques, Université de Montréal, Saint-Hyacinthe, QC, J2S7C6, Canada.
| | - Charlène Rico
- Département de Biomédecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, QC, J2S7C6, Canada.
| | - Mayra Tsoi
- Département de Biomédecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, QC, J2S7C6, Canada.
| | - Mélanie Vivancos
- Département de Biomédecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, QC, J2S7C6, Canada.
| | - Sabin Filimon
- Département de Biomédecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, QC, J2S7C6, Canada.
| | - Marilène Paquet
- Département de Pathologie et de Microbiologie, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, QC, J2S7C6, Canada.
| | - Derek Boerboom
- Département de Biomédecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, QC, J2S7C6, Canada.
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Køhler JB, Jørgensen MLM, Beinoraité G, Thorsen M, Thon G. Concerted action of the ubiquitin-fusion degradation protein 1 (Ufd1) and Sumo-targeted ubiquitin ligases (STUbLs) in the DNA-damage response. PLoS One 2013; 8:e80442. [PMID: 24265825 PMCID: PMC3827193 DOI: 10.1371/journal.pone.0080442] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2013] [Accepted: 10/02/2013] [Indexed: 01/04/2023] Open
Abstract
In eukaryotes many players in the DNA-damage response (DDR) catalyze protein sumoylation or ubiquitylation. Emphasis has been placed on how these modifications orchestrate the sequential recruitment of repair factors to sites of DNA damage or stalled replication forks. Here, we shed light on a pathway in which sumoylated factors are eliminated through the coupled action of Sumo-targeted ubiquitin ligases (STUbLs) and the ubiquitin-fusion degradation protein 1 (Ufd1). Ufd1 is a subunit of the Cdc48-Ufd1-Npl4 complex implicated in the sorting of ubiquitylated substrates for degradation by the proteasome. We find that in fission yeast, Ufd1 interacts physically and functionally with the Sumo-targeted ubiquitin ligase (STUbL) Rfp1, homologous to human RNF4, and with the Sumo E3 ligase Pli1, homologous to human PIAS1. Deleting a C-terminal domain of Ufd1 that mediates the interaction of Ufd1 with Rfp1, Pli1, and Sumo (ufd1ΔCt213-342) lead to an accumulation of high-molecular-weight Sumo conjugates and caused severe genomic instabilities. The spectrum of sensitivity of ufd1ΔCt213-342 cells to genotoxins, the epistatic relationships of ufd1ΔCt213-342 with mutations in DNA repair factors, and the localization of the repair factor Rad22 in ufd1ΔCt213-342 cells point to ufd1ΔCt213-342 cells accumulating aberrant structures during replication that require homologous recombination (HR) for their repair. We present evidence that HR is however often not successful in ufd1ΔCt213-342 cells and we identify Rad22 as one of the high-molecular-weight conjugates accumulating in the ufd1ΔCt213-342 mutant consistent with Rad22 being a STUbL/Ufd1 substrate. Suggesting a direct role of Ufd1 in the processing of Sumo-conjugates, Ufd1 formed nuclear foci colocalizing with Sumo during the DDR, and Sumo-conjugates accumulated in foci in the ufd1ΔCt213-342 mutant. Broader functional relationships between Ufd1 and STUbLs conceivably affect numerous cellular processes beyond the DDR.
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Mermershtain I, Glover JNM. Structural mechanisms underlying signaling in the cellular response to DNA double strand breaks. Mutat Res 2013; 750:15-22. [PMID: 23896398 DOI: 10.1016/j.mrfmmm.2013.07.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Revised: 07/12/2013] [Accepted: 07/16/2013] [Indexed: 01/04/2023]
Abstract
DNA double strand breaks (DSBs) constitute one of the most dangerous forms of DNA damage. In actively replicating cells, these breaks are first recognized by specialized proteins that initiate a signal transduction cascade that modulates the cell cycle and results in the repair of the breaks by homologous recombination (HR). Protein signaling in response to double strand breaks involves phosphorylation and ubiquitination of chromatin and a variety of associated proteins. Here we review the emerging structural principles that underlie how post-translational protein modifications control protein signaling that emanates from these DNA lesions.
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Affiliation(s)
- Inbal Mermershtain
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
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26
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Fessart D, Marza E, Taouji S, Delom F, Chevet E. P97/CDC-48: proteostasis control in tumor cell biology. Cancer Lett 2013; 337:26-34. [PMID: 23726843 DOI: 10.1016/j.canlet.2013.05.030] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Revised: 05/16/2013] [Accepted: 05/23/2013] [Indexed: 12/17/2022]
Abstract
P97/CDC-48 is a prominent member of a highly evolutionary conserved Walker cassette - containing AAA+ATPases. It has been involved in numerous cellular processes ranging from the control of protein homeostasis to membrane trafficking through the intervention of specific accessory proteins. Expression of p97/CDC-48 in cancers has been correlated with tumor aggressiveness and prognosis, however the precise underlying molecular mechanisms remain to be characterized. Moreover p97/CDC-48 inhibitors were developed and are currently under intense investigation as anticancer drugs. Herein, we discuss the role of p97/CDC-48 in cancer development and its therapeutic potential in tumor cell biology.
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Vaz B, Halder S, Ramadan K. Role of p97/VCP (Cdc48) in genome stability. Front Genet 2013; 4:60. [PMID: 23641252 PMCID: PMC3639377 DOI: 10.3389/fgene.2013.00060] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Accepted: 04/05/2013] [Indexed: 11/13/2022] Open
Abstract
Ubiquitin-dependent molecular chaperone p97, also known as valosin-containing protein (VCP) or Cdc48, is an AAA ATPase involved in protein turnover and degradation. p97 converts its own ATPase hydrolysis into remodeling activity on a myriad of ubiquitinated substrates from different cellular locations and pathways. In this way, p97 mediates extraction of targeted protein from cellular compartments or protein complexes. p97-dependent protein extraction from various cellular environments maintains cellular protein homeostasis. In recent years, p97-dependent protein extraction from chromatin has emerged as an essential evolutionarily conserved process for maintaining genome stability. Inactivation of p97 segregase activity leads to accumulation of ubiquitinated substrates on chromatin, consequently leading to protein-induced chromatin stress (PICHROS). PICHROS directly and negatively affects multiple DNA metabolic processes, including replication, damage responses, mitosis, and transcription, leading to genotoxic stress and genome instability. By summarizing and critically evaluating recent data on p97 function in various chromatin-associated protein degradation processes, we propose establishing p97 as a genome caretaker.
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Affiliation(s)
- Bruno Vaz
- Institute of Pharmacology and Toxicology, University Zürich-Vetsuisse Zürich, Switzerland ; Gray Institute for Radiation Oncology and Biology, Department of Oncology, University of Oxford Oxford, UK
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Franz A, Ackermann L, Hoppe T. Create and preserve: proteostasis in development and aging is governed by Cdc48/p97/VCP. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1843:205-15. [PMID: 23583830 DOI: 10.1016/j.bbamcr.2013.03.031] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Revised: 03/08/2013] [Accepted: 03/25/2013] [Indexed: 12/24/2022]
Abstract
The AAA-ATPase Cdc48 (also called p97 or VCP) acts as a key regulator in proteolytic pathways, coordinating recruitment and targeting of substrate proteins to the 26S proteasome or lysosomal degradation. However, in contrast to the well-known function in ubiquitin-dependent cellular processes, the physiological relevance of Cdc48 in organismic development and maintenance of protein homeostasis is less understood. Therefore, studies on multicellular model organisms help to decipher how Cdc48-dependent proteolysis is regulated in time and space to meet developmental requirements. Given the importance of developmental regulation and tissue maintenance, defects in Cdc48 activity have been linked to several human pathologies including protein aggregation diseases. Thus, addressing the underlying disease mechanisms not only contributes to our understanding on the organism-wide function of Cdc48 but also facilitates the design of specific medical therapies. In this review, we will portray the role of Cdc48 in the context of multicellular organisms, pointing out its importance for developmental processes, tissue surveillance, and disease prevention. This article is part of a Special Issue entitled: Ubiquitin-Proteasome System. Guest Editors: Thomas Sommer and Dieter H. Wolf.
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Affiliation(s)
- André Franz
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Zülpicher Straße 47a, 50674 Cologne, Germany
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29
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Pinder JB, Attwood KM, Dellaire G. Reading, writing, and repair: the role of ubiquitin and the ubiquitin-like proteins in DNA damage signaling and repair. Front Genet 2013; 4:45. [PMID: 23554604 PMCID: PMC3612592 DOI: 10.3389/fgene.2013.00045] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Accepted: 03/13/2013] [Indexed: 12/14/2022] Open
Abstract
Genomic instability is both a hallmark of cancer and a major contributing factor to tumor development. Central to the maintenance of genome stability is the repair of DNA damage, and the most toxic form of DNA damage is the DNA double-strand break. As a consequence the eukaryotic cell harbors an impressive array of protein machinery to detect and repair DNA breaks through the initiation of a multi-branched, highly coordinated signaling cascade. This signaling cascade, known as the DNA damage response (DDR), functions to integrate DNA repair with a host of cellular processes including cell cycle checkpoint activation, transcriptional regulation, and programmed cell death. In eukaryotes, DNA is packaged in chromatin, which provides a mechanism to regulate DNA transactions including DNA repair through an equally impressive array of post-translational modifications to proteins within chromatin, and the DDR machinery itself. Histones, as the major protein component of chromatin, are subject to a host of post-translational modifications including phosphorylation, methylation, and acetylation. More recently, modification of both the histones and DDR machinery by ubiquitin and other ubiquitin-like proteins, such as the small ubiquitin-like modifiers, has been shown to play a central role in coordinating the DDR. In this review, we explore how ubiquitination and sumoylation contribute to the “writing” of key post-translational modifications within chromatin that are in turn “read” by the DDR machinery and chromatin-remodeling factors, which act together to facilitate the efficient detection and repair of DNA damage.
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Affiliation(s)
- Jordan B Pinder
- Department of Pathology, Dalhousie University Halifax, NS, Canada
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30
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Abstract
Comment on: Macurek L, et al. Cell Cycle 2012; 12:251-62.
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Affiliation(s)
- Bruno Vaz
- Institute of Pharmacology and Toxicology, University of Zürich-Vetsuisse, Zürich, Switzerland
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31
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Altmeyer M, Lukas J. To spread or not to spread--chromatin modifications in response to DNA damage. Curr Opin Genet Dev 2013; 23:156-65. [PMID: 23312207 DOI: 10.1016/j.gde.2012.11.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Revised: 10/31/2012] [Accepted: 11/05/2012] [Indexed: 10/27/2022]
Abstract
Chromatin modifications in response to DNA damage are vital for genome integrity. Multiple proteins and pathways required to generate specialized chromatin domains around DNA lesions have been identified and the increasing amount of information calls for unifying concepts that would allow us to grasp the ever-increasing complexity. This review aims at contributing to this trend by focusing on feed-forward and feedback mechanisms, which in mammalian cells determine the extent of chromatin modifications after DNA damage. We highlight the emerging notion that the nodal points of these highly dynamic pathways operate in a rate-limiting mode, whose deregulation can disrupt physiological boundaries between damaged and undamaged chromatin, dictate repair pathway choice, and determine the fate of cells exposed to genotoxic stress.
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Affiliation(s)
- Matthias Altmeyer
- Chromosome Stability and Dynamics Unit, Department of Disease Biology, Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Blegdamsvej 3B, DK-2200 Copenhagen, Denmark.
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Mattiroli F, Vissers JHA, van Dijk WJ, Ikpa P, Citterio E, Vermeulen W, Marteijn JA, Sixma TK. RNF168 ubiquitinates K13-15 on H2A/H2AX to drive DNA damage signaling. Cell 2012; 150:1182-95. [PMID: 22980979 DOI: 10.1016/j.cell.2012.08.005] [Citation(s) in RCA: 514] [Impact Index Per Article: 39.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2012] [Revised: 05/29/2012] [Accepted: 07/09/2012] [Indexed: 01/01/2023]
Abstract
Ubiquitin-dependent signaling during the DNA damage response (DDR) to double-strand breaks (DSBs) is initiated by two E3 ligases, RNF8 and RNF168, targeting histone H2A and H2AX. RNF8 is the first ligase recruited to the damage site, and RNF168 follows RNF8-dependent ubiquitination. This suggests that RNF8 initiates H2A/H2AX ubiquitination with K63-linked ubiquitin chains and RNF168 extends them. Here, we show that RNF8 is inactive toward nucleosomal H2A, whereas RNF168 catalyzes the monoubiquitination of the histones specifically on K13-15. Structure-based mutagenesis of RNF8 and RNF168 RING domains shows that a charged residue determines whether nucleosomal proteins are recognized. We find that K63 ubiquitin chains are conjugated to RNF168-dependent H2A/H2AX monoubiquitination at K13-15 and not on K118-119. Using a mutant of RNF168 unable to target histones but still catalyzing ubiquitin chains at DSBs, we show that ubiquitin chains per se are insufficient for signaling, but RNF168 target ubiquitination is required for DDR.
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Affiliation(s)
- Francesca Mattiroli
- Division of Biochemistry and Center for Biomedical Genetics, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
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Dantuma NP, Hoppe T. Growing sphere of influence: Cdc48/p97 orchestrates ubiquitin-dependent extraction from chromatin. Trends Cell Biol 2012; 22:483-91. [PMID: 22818974 DOI: 10.1016/j.tcb.2012.06.003] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Revised: 06/14/2012] [Accepted: 06/18/2012] [Indexed: 11/30/2022]
Abstract
The AAA (ATPases associated with various cellular activities) family member Cdc48/p97 is best known for its role in ubiquitin-dependent proteasomal degradation of aberrant endoplasmic reticulum (ER) proteins, a process known as ER-associated degradation (ERAD). However, recent studies have also defined Cdc48/p97 as a central player in various chromatin-associated processes linked to cell cycle progression, DNA replication, transcription, and the DNA damage response. Notwithstanding the apparent differences in location and function, the role of Cdc48/p97 in ubiquitin-dependent extraction from chromatin (UDEC) bears striking similarities with its action in ERAD. Here, we discuss recent data that expand our current model of the role of Cdc48/p97 as a ubiquitin-selective segregase in the nuclear chromatin environment.
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Affiliation(s)
- Nico P Dantuma
- Department of Cell and Molecular Biology, Karolinska Institutet, von Eulers väg 3, S-17177 Stockholm, Sweden.
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34
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Thompson LH. Recognition, signaling, and repair of DNA double-strand breaks produced by ionizing radiation in mammalian cells: the molecular choreography. Mutat Res 2012; 751:158-246. [PMID: 22743550 DOI: 10.1016/j.mrrev.2012.06.002] [Citation(s) in RCA: 261] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Revised: 06/09/2012] [Accepted: 06/16/2012] [Indexed: 12/15/2022]
Abstract
The faithful maintenance of chromosome continuity in human cells during DNA replication and repair is critical for preventing the conversion of normal diploid cells to an oncogenic state. The evolution of higher eukaryotic cells endowed them with a large genetic investment in the molecular machinery that ensures chromosome stability. In mammalian and other vertebrate cells, the elimination of double-strand breaks with minimal nucleotide sequence change involves the spatiotemporal orchestration of a seemingly endless number of proteins ranging in their action from the nucleotide level to nucleosome organization and chromosome architecture. DNA DSBs trigger a myriad of post-translational modifications that alter catalytic activities and the specificity of protein interactions: phosphorylation, acetylation, methylation, ubiquitylation, and SUMOylation, followed by the reversal of these changes as repair is completed. "Superfluous" protein recruitment to damage sites, functional redundancy, and alternative pathways ensure that DSB repair is extremely efficient, both quantitatively and qualitatively. This review strives to integrate the information about the molecular mechanisms of DSB repair that has emerged over the last two decades with a focus on DSBs produced by the prototype agent ionizing radiation (IR). The exponential growth of molecular studies, heavily driven by RNA knockdown technology, now reveals an outline of how many key protein players in genome stability and cancer biology perform their interwoven tasks, e.g. ATM, ATR, DNA-PK, Chk1, Chk2, PARP1/2/3, 53BP1, BRCA1, BRCA2, BLM, RAD51, and the MRE11-RAD50-NBS1 complex. Thus, the nature of the intricate coordination of repair processes with cell cycle progression is becoming apparent. This review also links molecular abnormalities to cellular pathology as much a possible and provides a framework of temporal relationships.
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Affiliation(s)
- Larry H Thompson
- Biology & Biotechnology Division, L452, Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, CA 94551-0808, United States.
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