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Ohashi E, Tsurimoto T. Functions of Multiple Clamp and Clamp-Loader Complexes in Eukaryotic DNA Replication. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1042:135-162. [PMID: 29357057 DOI: 10.1007/978-981-10-6955-0_7] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Proliferating cell nuclear antigen (PCNA) and replication factor C (RFC) were identified in the late 1980s as essential factors for replication of simian virus 40 DNA in human cells, by reconstitution of the reaction in vitro. Initially, they were only thought to be involved in the elongation stage of DNA replication. Subsequent studies have demonstrated that PCNA functions as more than a replication factor, through its involvement in multiple protein-protein interactions. PCNA appears as a functional hub on replicating and replicated chromosomal DNA and has an essential role in the maintenance genome integrity in proliferating cells.Eukaryotes have multiple paralogues of sliding clamp, PCNA and its loader, RFC. The PCNA paralogues, RAD9, HUS1, and RAD1 form the heterotrimeric 9-1-1 ring that is similar to the PCNA homotrimeric ring, and the 9-1-1 clamp complex is loaded onto sites of DNA damage by its specific loader RAD17-RFC. This alternative clamp-loader system transmits DNA-damage signals in genomic DNA to the checkpoint-activation network and the DNA-repair apparatus.Another two alternative loader complexes, CTF18-RFC and ELG1-RFC, have roles that are distinguishable from the role of the canonical loader, RFC. CTF18-RFC interacts with one of the replicative DNA polymerases, Polε, and loads PCNA onto leading-strand DNA, and ELG1-RFC unloads PCNA after ligation of lagging-strand DNA. In the progression of S phase, these alternative PCNA loaders maintain appropriate amounts of PCNA on the replicating sister DNAs to ensure that specific enzymes are tethered at specific chromosomal locations.
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Affiliation(s)
- Eiji Ohashi
- Department of Biology, Faculty of Science, Kyushu University, Fukuoka, Japan
| | - Toshiki Tsurimoto
- Department of Biology, Faculty of Science, Kyushu University, Fukuoka, Japan.
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Shanmugam I, Abbas M, Ayoub F, Mirabal S, Bsaili M, Caulder EK, Weinstock DM, Tomkinson AE, Hromas R, Shaheen M. Ubiquitin-specific peptidase 20 regulates Rad17 stability, checkpoint kinase 1 phosphorylation and DNA repair by homologous recombination. J Biol Chem 2014; 289:22739-22748. [PMID: 24923443 DOI: 10.1074/jbc.m114.550459] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Rad17 is a subunit of the Rad9-Hus1-Rad1 clamp loader complex, which is required for Chk1 activation after DNA damage. Rad17 has been shown to be regulated by the ubiquitin-proteasome system. We have identified a deubiquitylase, USP20 that is required for Rad17 protein stability in the steady-state and post DNA damage. We demonstrate that USP20 and Rad17 interact, and that this interaction is enhanced by UV exposure. We show that USP20 regulation of Rad17 is at the protein level in a proteasome-dependent manner. USP20 depletion results in poor activation of Chk1 protein by phosphorylation, consistent with Rad17 role in ATR-mediated phosphorylation of Chk1. Similar to other DNA repair proteins, USP20 is phosphorylated post DNA damage, and its depletion sensitizes cancer cells to damaging agents that form blocks ahead of the replication forks. Similar to Chk1 and Rad17, which enhance recombinational repair of collapsed replication forks, we demonstrate that USP20 depletion impairs DNA double strand break repair by homologous recombination. Together, our data establish a new function of USP20 in genome maintenance and DNA repair.
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Affiliation(s)
- Ilanchezhian Shanmugam
- Division of Hematology-Oncology, Dept of Internal Medicine, and the Cancer Center, University Of New Mexico, Albuquerque, New Mexico 87131
| | - Mohammad Abbas
- Division of Hematology-Oncology, Dept of Internal Medicine, and the Cancer Center, University Of New Mexico, Albuquerque, New Mexico 87131
| | - Farhan Ayoub
- Division of Hematology-Oncology, Dept of Internal Medicine, and the Cancer Center, University Of New Mexico, Albuquerque, New Mexico 87131
| | - Susan Mirabal
- Division of Hematology-Oncology, Dept of Internal Medicine, and the Cancer Center, University Of New Mexico, Albuquerque, New Mexico 87131
| | - Manal Bsaili
- Division of Hematology-Oncology, Dept of Internal Medicine, and the Cancer Center, University Of New Mexico, Albuquerque, New Mexico 87131
| | - Erin K Caulder
- Division of Hematology-Oncology, Dept of Internal Medicine, and the Cancer Center, University Of New Mexico, Albuquerque, New Mexico 87131
| | - David M Weinstock
- Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02215
| | - Alan E Tomkinson
- Division of Hematology-Oncology, Dept of Internal Medicine, and the Cancer Center, University Of New Mexico, Albuquerque, New Mexico 87131
| | - Robert Hromas
- Department of Medicine, University of Florida, Gainesville, Florida 32610, and
| | - Monte Shaheen
- Division of Hematology-Oncology, Dept of Internal Medicine, and the Cancer Center, University Of New Mexico, Albuquerque, New Mexico 87131,.
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Abstract
Rad17 is best known as a checkpoint clamp loader in the activation of ATR kinase signaling. A new study in The EMBO Journal suggests that it also plays a role in initial recruitment of the MRN complex to sites of DNA double-strand breaks, thereby promoting early ATM checkpoint responses and homologous recombination repair.
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Affiliation(s)
- Tanya T Paull
- The Department of Molecular Biosciences, The Howard Hughes Medical Institute, The University of Texas at AustinAustin, TX, USA
- Institute for Cellular and Molecular Biology, The University of Texas at AustinAustin, TX, USA
| | - Ji-Hoon Lee
- The Department of Molecular Biosciences, The Howard Hughes Medical Institute, The University of Texas at AustinAustin, TX, USA
- Institute for Cellular and Molecular Biology, The University of Texas at AustinAustin, TX, USA
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Wang Q, Goldstein M, Alexander P, Wakeman TP, Sun T, Feng J, Lou Z, Kastan MB, Wang XF. Rad17 recruits the MRE11-RAD50-NBS1 complex to regulate the cellular response to DNA double-strand breaks. EMBO J 2014; 33:862-77. [PMID: 24534091 PMCID: PMC4194111 DOI: 10.1002/embj.201386064] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2013] [Revised: 01/05/2014] [Accepted: 01/08/2014] [Indexed: 11/09/2022] Open
Abstract
The MRE11-RAD50-NBS1 (MRN) complex is essential for the detection of DNA double-strand breaks (DSBs) and initiation of DNA damage signaling. Here, we show that Rad17, a replication checkpoint protein, is required for the early recruitment of the MRN complex to the DSB site that is independent of MDC1 and contributes to ATM activation. Mechanistically, Rad17 is phosphorylated by ATM at a novel Thr622 site resulting in a direct interaction of Rad17 with NBS1, facilitating recruitment of the MRN complex and ATM to the DSB, thereby enhancing ATM signaling. Repetition of these events creates a positive feedback for Rad17-dependent activation of MRN/ATM signaling which appears to be a requisite for the activation of MDC1-dependent MRN complex recruitment. A point mutation of the Thr622 residue of Rad17 leads to a significant reduction in MRN/ATM signaling and homologous recombination repair, suggesting that Thr622 phosphorylation is important for regulation of the MRN/ATM signaling by Rad17. These findings suggest that Rad17 plays a critical role in the cellular response to DNA damage via regulation of the MRN/ATM pathway.
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Affiliation(s)
- Qinhong Wang
- Department of Pharmacology and Cancer Biology, Duke University Medical CenterDurham, NC, USA
| | - Michael Goldstein
- Department of Pharmacology and Cancer Biology, Duke University Medical CenterDurham, NC, USA
- Duke Cancer Institute, Duke University Medical CenterDurham, NC, USA
| | - Peter Alexander
- Department of Pharmacology and Cancer Biology, Duke University Medical CenterDurham, NC, USA
| | - Timothy P Wakeman
- Department of Pharmacology and Cancer Biology, Duke University Medical CenterDurham, NC, USA
| | - Tao Sun
- Department of Pharmacology and Cancer Biology, Duke University Medical CenterDurham, NC, USA
| | - Junjie Feng
- Department of Pharmacology and Cancer Biology, Duke University Medical CenterDurham, NC, USA
| | - Zhenkun Lou
- Division of Oncology Research and Department of Molecular Pharmacology and Experimental Therapeutics, Mayo ClinicRochester, MN, USA
| | - Michael B Kastan
- Department of Pharmacology and Cancer Biology, Duke University Medical CenterDurham, NC, USA
- Duke Cancer Institute, Duke University Medical CenterDurham, NC, USA
| | - Xiao-Fan Wang
- Department of Pharmacology and Cancer Biology, Duke University Medical CenterDurham, NC, USA
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Bruno T, Desantis A, Bossi G, Di Agostino S, Sorino C, De Nicola F, Iezzi S, Franchitto A, Benassi B, Galanti S, La Rosa F, Floridi A, Bellacosa A, Passananti C, Blandino G, Fanciulli M. Che-1 promotes tumor cell survival by sustaining mutant p53 transcription and inhibiting DNA damage response activation. Cancer Cell 2010; 18:122-34. [PMID: 20708154 DOI: 10.1016/j.ccr.2010.05.027] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2009] [Revised: 04/06/2010] [Accepted: 06/23/2010] [Indexed: 11/25/2022]
Abstract
Che-1 is a RNA polymerase II binding protein involved in the regulation of gene transcription and, in response to DNA damage, promotes p53 transcription. In this study, we investigated whether Che-1 regulates mutant p53 expression. We found that Che-1 is required for sustaining mutant p53 expression in several cancer cell lines, and that Che-1 depletion by siRNA induces apoptosis both in vitro and in vivo. Notably, loss of Che-1 activates DNA damage checkpoint response and induces transactivation of p73. Therefore, these findings underline the important role that Che-1 has in survival of cells expressing mutant p53.
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Affiliation(s)
- Tiziana Bruno
- Department of Therapeutic Programs Development, Regina Elena Cancer Institute, Rome, Italy
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