1
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Yuan Z, Georgescu R, Yao NY, Yurieva O, O'Donnell ME, Li H. Mechanism of PCNA loading by Ctf18-RFC for leading-strand DNA synthesis. Science 2024; 385:eadk5901. [PMID: 39088616 DOI: 10.1126/science.adk5901] [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: 08/30/2023] [Revised: 02/10/2024] [Accepted: 05/31/2024] [Indexed: 08/03/2024]
Abstract
The proliferating cell nuclear antigen (PCNA) clamp encircles DNA to hold DNA polymerases (Pols) to DNA for processivity. The Ctf18-RFC PCNA loader, a replication factor C (RFC) variant, is specific to the leading-strand Pol (Polε). We reveal here the underlying mechanism of Ctf18-RFC specificity to Polε using cryo-electron microscopy and biochemical studies. We found that both Ctf18-RFC and Polε contain specific structural features that direct PCNA loading onto DNA. Unlike other clamp loaders, Ctf18-RFC has a disordered ATPase associated with a diverse cellular activities (AAA+) motor that requires Polε to bind and stabilize it for efficient PCNA loading. In addition, Ctf18-RFC can pry prebound Polε off of DNA, then load PCNA onto DNA and transfer the PCNA-DNA back to Polε. These elements in both Ctf18-RFC and Polε provide specificity in loading PCNA onto DNA for Polε.
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Affiliation(s)
- Zuanning Yuan
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI, USA
| | - Roxana Georgescu
- DNA Replication Laboratory, The Rockefeller University, New York, NY, USA
- Howard Hughes Medical Institute, New York, NY, USA
| | - Nina Y Yao
- DNA Replication Laboratory, The Rockefeller University, New York, NY, USA
| | - Olga Yurieva
- DNA Replication Laboratory, The Rockefeller University, New York, NY, USA
- Howard Hughes Medical Institute, New York, NY, USA
| | - Michael E O'Donnell
- DNA Replication Laboratory, The Rockefeller University, New York, NY, USA
- Howard Hughes Medical Institute, New York, NY, USA
| | - Huilin Li
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI, USA
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2
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Joris S, Giron P, Olsen C, Seneca S, Gheldof A, Staessens S, Shahi RB, De Brakeleer S, Teugels E, De Grève J, Hes FJ. Identification of RAD17 as a candidate cancer predisposition gene in families with histories of pancreatic and breast cancers. BMC Cancer 2024; 24:723. [PMID: 38872153 PMCID: PMC11170902 DOI: 10.1186/s12885-024-12442-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 05/28/2024] [Indexed: 06/15/2024] Open
Abstract
BACKGROUND Among the 10% of pancreatic cancers that occur in a familial context, around a third carry a pathogenic variant in a cancer predisposition gene. Genetic studies of pancreatic cancer predisposition are limited by high mortality rates amongst index patients and other affected family members. The genetic risk for pancreatic cancer is often shared with breast cancer susceptibility genes, most notably BRCA2, PALB2, ATM and BRCA1. Therefore, we hypothesized that additional shared genetic etiologies might be uncovered by studying families presenting with both breast and pancreatic cancer. METHODS Focusing on a multigene panel of 276 DNA Damage Repair (DDR) genes, we performed next-generation sequencing in a cohort of 41 families with at least three breast cancer cases and one pancreatic cancer. When the index patient with pancreatic cancer was deceased, close relatives (first or second-degree) affected with breast cancer were tested (39 families). RESULTS We identified 27 variants of uncertain significance in DDR genes. A splice site variant (c.1605 + 2T > A) in the RAD17 gene stood out, as a likely loss of function variant. RAD17 is a checkpoint protein that recruits the MRN (MRE11-RAD50-NBS1) complex to initiate DNA signaling, leading to DNA double-strand break repair. CONCLUSION Within families with breast and pancreatic cancer, we identified RAD17 as a novel candidate predisposition gene. Further genetic studies are warranted to better understand the potential pathogenic effect of RAD17 variants and in other DDR genes.
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Affiliation(s)
- Sofie Joris
- Clinical Sciences, Research Group Reproduction and Genetics, Centre for Medical Genetics, Universitair Ziekenhuis Brussel (UZ Brussel), Vrije Universiteit Brussel (VUB), Laarbeeklaan 101, Brussels, 1090, Belgium.
- The Oncology Research Center, the Laboratory for Medical & Molecular Oncology (LMMO), Faculty of Medicine, Vrije Universiteit Brussel (VUB), Brussels, Belgium.
| | - Philippe Giron
- Clinical Sciences, Research Group Reproduction and Genetics, Centre for Medical Genetics, Universitair Ziekenhuis Brussel (UZ Brussel), Vrije Universiteit Brussel (VUB), Laarbeeklaan 101, Brussels, 1090, Belgium
| | - Catharina Olsen
- Clinical Sciences, Research Group Reproduction and Genetics, Centre for Medical Genetics, Universitair Ziekenhuis Brussel (UZ Brussel), Vrije Universiteit Brussel (VUB), Laarbeeklaan 101, Brussels, 1090, Belgium
| | - Sara Seneca
- Clinical Sciences, Research Group Reproduction and Genetics, Centre for Medical Genetics, Universitair Ziekenhuis Brussel (UZ Brussel), Vrije Universiteit Brussel (VUB), Laarbeeklaan 101, Brussels, 1090, Belgium
| | - Alexander Gheldof
- Clinical Sciences, Research Group Reproduction and Genetics, Centre for Medical Genetics, Universitair Ziekenhuis Brussel (UZ Brussel), Vrije Universiteit Brussel (VUB), Laarbeeklaan 101, Brussels, 1090, Belgium
| | - Shula Staessens
- The Oncology Research Center, the Laboratory for Medical & Molecular Oncology (LMMO), Faculty of Medicine, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Rajendra Bahadur Shahi
- The Oncology Research Center, the Laboratory for Medical & Molecular Oncology (LMMO), Faculty of Medicine, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Sylvia De Brakeleer
- The Oncology Research Center, the Laboratory for Medical & Molecular Oncology (LMMO), Faculty of Medicine, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Erik Teugels
- The Oncology Research Center, the Laboratory for Medical & Molecular Oncology (LMMO), Faculty of Medicine, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Jacques De Grève
- Clinical Sciences, Research Group Reproduction and Genetics, Centre for Medical Genetics, Universitair Ziekenhuis Brussel (UZ Brussel), Vrije Universiteit Brussel (VUB), Laarbeeklaan 101, Brussels, 1090, Belgium
- The Oncology Research Center, the Laboratory for Medical & Molecular Oncology (LMMO), Faculty of Medicine, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Frederik J Hes
- Clinical Sciences, Research Group Reproduction and Genetics, Centre for Medical Genetics, Universitair Ziekenhuis Brussel (UZ Brussel), Vrije Universiteit Brussel (VUB), Laarbeeklaan 101, Brussels, 1090, Belgium
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3
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He Q, Wang F, O’Donnell ME, Li H. Cryo-EM reveals a nearly complete PCNA loading process and unique features of the human alternative clamp loader CTF18-RFC. Proc Natl Acad Sci U S A 2024; 121:e2319727121. [PMID: 38669181 PMCID: PMC11067034 DOI: 10.1073/pnas.2319727121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Accepted: 03/15/2024] [Indexed: 04/28/2024] Open
Abstract
The DNA sliding clamp PCNA is a multipurpose platform for DNA polymerases and many other proteins involved in DNA metabolism. The topologically closed PCNA ring needs to be cracked open and loaded onto DNA by a clamp loader, e.g., the well-studied pentameric ATPase complex RFC (RFC1-5). The CTF18-RFC complex is an alternative clamp loader found recently to bind the leading strand DNA polymerase ε and load PCNA onto leading strand DNA, but its structure and the loading mechanism have been unknown. By cryo-EM analysis of in vitro assembled human CTF18-RFC-DNA-PCNA complex, we have captured seven loading intermediates, revealing a detailed PCNA loading mechanism onto a 3'-ss/dsDNA junction by CTF18-RFC. Interestingly, the alternative loader has evolved a highly mobile CTF18 AAA+ module likely to lower the loading activity, perhaps to avoid competition with the RFC and to limit its role to leading strand clamp loading. To compensate for the lost stability due to the mobile AAA+ module, CTF18 has evolved a unique β-hairpin motif that reaches across RFC2 to interact with RFC5, thereby stabilizing the pentameric complex. Further, we found that CTF18 also contains a separation pin to locally melt DNA from the 3'-end of the primer; this ensures its ability to load PCNA to any 3'-ss/dsDNA junction, facilitated by the binding energy of the E-plug to the major groove. Our study reveals unique structural features of the human CTF18-RFC and contributes to a broader understanding of PCNA loading by the alternative clamp loaders.
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Affiliation(s)
- Qing He
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI49503
| | - Feng Wang
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI49503
| | - Michael E. O’Donnell
- DNA Replication Laboratory, The Rockefeller University, New York, NY10065
- HHMI, The Rockefeller University, New York, NY10065
| | - Huilin Li
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI49503
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4
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Kawasoe Y, Shimokawa S, Gillespie PJ, Blow JJ, Tsurimoto T, Takahashi TS. The Atad5 RFC-like complex is the major unloader of proliferating cell nuclear antigen in Xenopus egg extracts. J Biol Chem 2024; 300:105588. [PMID: 38141767 PMCID: PMC10827553 DOI: 10.1016/j.jbc.2023.105588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 12/04/2023] [Accepted: 12/11/2023] [Indexed: 12/25/2023] Open
Abstract
Proliferating cell nuclear antigen (PCNA) is a homo-trimeric clamp complex that serves as the molecular hub for various DNA transactions, including DNA synthesis and post-replicative mismatch repair. Its timely loading and unloading are critical for genome stability. PCNA loading is catalyzed by Replication factor C (RFC) and the Ctf18 RFC-like complex (Ctf18-RLC), and its unloading is catalyzed by Atad5/Elg1-RLC. However, RFC, Ctf18-RLC, and even some subcomplexes of their shared subunits are capable of unloading PCNA in vitro, leaving an ambiguity in the division of labor in eukaryotic clamp dynamics. By using a system that specifically detects PCNA unloading, we show here that Atad5-RLC, which accounts for only approximately 3% of RFC/RLCs, nevertheless provides the major PCNA unloading activity in Xenopus egg extracts. RFC and Ctf18-RLC each account for approximately 40% of RFC/RLCs, while immunodepletion of neither Rfc1 nor Ctf18 detectably affects the rate of PCNA unloading in our system. PCNA unloading is dependent on the ATP-binding motif of Atad5, independent of nicks on DNA and chromatin assembly, and inhibited effectively by PCNA-interacting peptides. These results support a model in which Atad5-RLC preferentially unloads DNA-bound PCNA molecules that are free from their interactors.
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Affiliation(s)
| | - Sakiko Shimokawa
- Graduate School of Systems Life Sciences, Kyushu University, Fukuoka, Japan
| | - Peter J Gillespie
- Division of Molecular, Cell & Developmental Biology, School of Life Sciences, University of Dundee, Dundee, UK
| | - J Julian Blow
- Division of Molecular, Cell & Developmental Biology, School of Life Sciences, University of Dundee, Dundee, UK
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5
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Park SH, Kim N, Kang N, Ryu E, Lee EA, Ra JS, Gartner A, Kang S, Myung K, Lee KY. Short-range end resection requires ATAD5-mediated PCNA unloading for faithful homologous recombination. Nucleic Acids Res 2023; 51:10519-10535. [PMID: 37739427 PMCID: PMC10602867 DOI: 10.1093/nar/gkad776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 09/01/2023] [Accepted: 09/12/2023] [Indexed: 09/24/2023] Open
Abstract
Homologous recombination (HR) requires bidirectional end resection initiated by a nick formed close to a DNA double-strand break (DSB), dysregulation favoring error-prone DNA end-joining pathways. Here we investigate the role of the ATAD5, a PCNA unloading protein, in short-range end resection, long-range resection not being affected by ATAD5 deficiency. Rapid PCNA loading onto DNA at DSB sites depends on the RFC PCNA loader complex and MRE11-RAD50-NBS1 nuclease complexes bound to CtIP. Based on our cytological analyses and on an in vitro system for short-range end resection, we propose that PCNA unloading by ATAD5 is required for the completion of short-range resection. Hampering PCNA unloading also leads to failure to remove the KU70/80 complex from the termini of DSBs hindering DNA repair synthesis and the completion of HR. In line with this model, ATAD5-depleted cells are defective for HR, show increased sensitivity to camptothecin, a drug forming protein-DNA adducts, and an augmented dependency on end-joining pathways. Our study highlights the importance of PCNA regulation at DSB for proper end resection and HR.
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Affiliation(s)
- Su Hyung Park
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Korea
- Department of Biomedical Engineering, College of Information-Bio Convergence Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, Korea
| | - Namwoo Kim
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Korea
- Department of Biological Sciences, College of Information-Bio Convergence Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, Korea
| | - Nalae Kang
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Korea
| | - Eunjin Ryu
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Korea
- Department of Biological Sciences, College of Information-Bio Convergence Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, Korea
| | - Eun A Lee
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Korea
| | - Jae Sun Ra
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Korea
| | - Anton Gartner
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Korea
- Department of Biological Sciences, College of Information-Bio Convergence Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, Korea
| | - Sukhyun Kang
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Korea
| | - Kyungjae Myung
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Korea
- Department of Biomedical Engineering, College of Information-Bio Convergence Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, Korea
| | - Kyoo-young Lee
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Korea
- Department of Biochemistry, College of Medicine, Hallym University, Chuncheon 24252, Korea
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6
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Hara K, Hishiki A, Hoshino T, Nagata K, Iida N, Sawada Y, Ohashi E, Hashimoto H. The 9-1-1 DNA clamp subunit RAD1 forms specific interactions with clamp loader RAD17, revealing functional implications for binding-protein RHINO. J Biol Chem 2023; 299:103061. [PMID: 36841485 PMCID: PMC10060742 DOI: 10.1016/j.jbc.2023.103061] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 02/18/2023] [Accepted: 02/20/2023] [Indexed: 02/27/2023] Open
Abstract
The RAD9-RAD1-HUS1 complex (9-1-1) is a eukaryotic DNA clamp with a crucial role at checkpoints for DNA damage. The ring-like structure of 9-1-1 is opened for loading onto 5' recessed DNA by the clamp loader RAD17 RFC-like complex (RAD17-RLC), in which the RAD17 subunit is responsible for specificity to 9-1-1. Loading of 9-1-1 is required for activation of the ATR-CHK1 checkpoint pathway and the activation is stimulated by a 9-1-1 interacting protein, RHINO, which interacts with 9-1-1 via a recently identified RAD1-binding motif. This discovery led to the hypothesis that other interacting proteins may contain a RAD1-binding motif as well. Here, we show that vertebrate RAD17 proteins also have a putative RAD1-binding motif in their N-terminal regions, and we report the crystal structure of human 9-1-1 bound to a human RAD17 peptide incorporating the motif at 2.1 Å resolution. Our structure confirms that the N-terminal region of RAD17 binds to the RAD1 subunit of 9-1-1 via specific interactions. Furthermore, we show that the RAD1-binding motif of RHINO disturbs the interaction of the N-terminal region of RAD17 with 9-1-1. Our results provide deeper understanding of how RAD17-RLC specifically recognizes 9-1-1 and imply that RHINO has a functional role in 9-1-1 loading/unloading and checkpoint activation.
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Affiliation(s)
- Kodai Hara
- School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
| | - Asami Hishiki
- School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
| | - Takako Hoshino
- School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
| | - Kiho Nagata
- School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
| | - Nao Iida
- School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
| | - Yukimasa Sawada
- School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
| | - Eiji Ohashi
- Department of Biology, Faculty of Science, Kyushu University, Fukuoka, Japan
| | - Hiroshi Hashimoto
- School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan.
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7
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Effects of Defective Unloading and Recycling of PCNA Revealed by the Analysis of ELG1 Mutants. Int J Mol Sci 2023; 24:ijms24021568. [PMID: 36675081 PMCID: PMC9863317 DOI: 10.3390/ijms24021568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 01/10/2023] [Accepted: 01/11/2023] [Indexed: 01/15/2023] Open
Abstract
Timely and complete replication of the genome is essential for life. The PCNA ring plays an essential role in DNA replication and repair by contributing to the processivity of DNA polymerases and by recruiting proteins that act in DNA replication-associated processes. The ELG1 gene encodes a protein that works, together with the Rfc2-5 subunits (shared by the replication factor C complex), to unload PCNA from chromatin. While ELG1 is not essential for life, deletion of the gene has strong consequences for the stability of the genome, and elg1 mutants exhibit sensitivity to DNA damaging agents, defects in genomic silencing, high mutation rates, and other striking phenotypes. Here, we sought to understand whether all the roles attributed to Elg1 in genome stability maintenance are due to its effects on PCNA unloading, or whether they are due to additional functions of the protein. By using a battery of mutants that affect PCNA accumulation at various degrees, we show that all the phenotypes measured correlate with the amount of PCNA left at the chromatin. Our results thus demonstrate the importance of Elg1 and of PCNA unloading in promoting proper chromatin structure and in maintaining a stable genome.
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8
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Kim S, Kim Y, Kim Y, Yoon S, Lee KY, Lee Y, Kang S, Myung K, Oh CK. PCNA Ser46-Leu47 residues are crucial in preserving genomic integrity. PLoS One 2023; 18:e0285337. [PMID: 37205694 DOI: 10.1371/journal.pone.0285337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 04/19/2023] [Indexed: 05/21/2023] Open
Abstract
Proliferating cell nuclear antigen (PCNA) is a maestro of DNA replication. PCNA forms a homotrimer and interacts with various proteins, such as DNA polymerases, DNA ligase I (LIG1), and flap endonuclease 1 (FEN1) for faithful DNA replication. Here, we identify the crucial role of Ser46-Leu47 residues of PCNA in maintaining genomic integrity using in vitro, and cell-based assays and structural prediction. The predicted PCNAΔSL47 structure shows the potential distortion of the central loop and reduced hydrophobicity. PCNAΔSL47 shows a defective interaction with PCNAWT leading to defects in homo-trimerization in vitro. PCNAΔSL47 is defective in the FEN1 and LIG1 interaction. PCNA ubiquitination and DNA-RNA hybrid processing are defective in PCNAΔSL47-expressing cells. Accordingly, PCNAΔSL47-expressing cells exhibit an increased number of single-stranded DNA gaps and higher levels of γH2AX, and sensitivity to DNA-damaging agents, highlighting the importance of PCNA Ser46-Leu47 residues in maintaining genomic integrity.
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Affiliation(s)
- Sangin Kim
- Institute for Basic Science, Center for Genomic Integrity, Ulsan, Korea
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, College of Information-Bio Convergence Engineering, Ulsan, Korea
| | - Yeongjae Kim
- Institute for Basic Science, Center for Genomic Integrity, Ulsan, Korea
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, College of Information-Bio Convergence Engineering, Ulsan, Korea
| | - Youyoung Kim
- Institute for Basic Science, Center for Genomic Integrity, Ulsan, Korea
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, College of Information-Bio Convergence Engineering, Ulsan, Korea
| | - Suhyeon Yoon
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Integrated Data Sciences Section, Research Technologies Branch, Bethesda, MD, United States of America
| | - Kyoo-Young Lee
- Institute for Basic Science, Center for Genomic Integrity, Ulsan, Korea
- Department of Biochemistry, College of Medicine, Hallym University, Chuncheon, Gangwon-do, Korea
| | - Yoonsung Lee
- Clinical Research Institute, Kyung Hee University Hospital at Gangdong, College of Medicine, Kyung Hee University, Seoul, Korea
| | - Sukhyun Kang
- Institute for Basic Science, Center for Genomic Integrity, Ulsan, Korea
| | - Kyungjae Myung
- Institute for Basic Science, Center for Genomic Integrity, Ulsan, Korea
- Ulsan National Institute of Science and Technology, Department of Biomedical Engineering, College of Information-Bio Convergence Engineering, Ulsan, Korea
| | - Chang-Kyu Oh
- Department of Biochemistry, Pusan National University, School of Medicine, Yangsan, Korea
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9
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Schrecker M, Castaneda JC, Devbhandari S, Kumar C, Remus D, Hite RK. Multistep loading of a DNA sliding clamp onto DNA by replication factor C. eLife 2022; 11:e78253. [PMID: 35939393 PMCID: PMC9359705 DOI: 10.7554/elife.78253] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 07/07/2022] [Indexed: 11/13/2022] Open
Abstract
The DNA sliding clamp proliferating cell nuclear antigen (PCNA) is an essential co-factor for many eukaryotic DNA metabolic enzymes. PCNA is loaded around DNA by the ATP-dependent clamp loader replication factor C (RFC), which acts at single-stranded (ss)/double-stranded DNA (dsDNA) junctions harboring a recessed 3' end (3' ss/dsDNA junctions) and at DNA nicks. To illuminate the loading mechanism we have investigated the structure of RFC:PCNA bound to ATPγS and 3' ss/dsDNA junctions or nicked DNA using cryogenic electron microscopy. Unexpectedly, we observe open and closed PCNA conformations in the RFC:PCNA:DNA complex, revealing that PCNA can adopt an open, planar conformation that allows direct insertion of dsDNA, and raising the question of whether PCNA ring closure is mechanistically coupled to ATP hydrolysis. By resolving multiple DNA-bound states of RFC:PCNA we observe that partial melting facilitates lateral insertion into the central channel formed by RFC:PCNA. We also resolve the Rfc1 N-terminal domain and demonstrate that its single BRCT domain participates in coordinating DNA prior to insertion into the central RFC channel, which promotes PCNA loading on the lagging strand of replication forks in vitro. Combined, our data suggest a comprehensive and fundamentally revised model for the RFC-catalyzed loading of PCNA onto DNA.
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Affiliation(s)
- Marina Schrecker
- Structural Biology Program, Memorial Sloan Kettering Cancer CenterNew YorkUnited States
| | - Juan C Castaneda
- Weill Cornell Medicine Graduate School, Weill Cornell MedicineNew YorkUnited States
- Molecular Biology Program, Memorial Sloan Kettering Cancer CenterNew YorkUnited States
| | - Sujan Devbhandari
- Molecular Biology Program, Memorial Sloan Kettering Cancer CenterNew YorkUnited States
| | - Charanya Kumar
- Molecular Biology Program, Memorial Sloan Kettering Cancer CenterNew YorkUnited States
| | - Dirk Remus
- Molecular Biology Program, Memorial Sloan Kettering Cancer CenterNew YorkUnited States
| | - Richard K Hite
- Structural Biology Program, Memorial Sloan Kettering Cancer CenterNew YorkUnited States
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10
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Zheng F, Georgescu RE, Yao NY, Li H, O'Donnell ME. Cryo-EM structures reveal that RFC recognizes both the 3'- and 5'-DNA ends to load PCNA onto gaps for DNA repair. eLife 2022; 11:77469. [PMID: 35829698 PMCID: PMC9293004 DOI: 10.7554/elife.77469] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 06/06/2022] [Indexed: 12/27/2022] Open
Abstract
RFC uses ATP to assemble PCNA onto primed sites for replicative DNA polymerases d and e. The RFC pentamer forms a central chamber that binds 3' ss/ds DNA junctions to load PCNA onto DNA during replication. We show here five structures that identify a 2nd DNA binding site in RFC that binds a 5' duplex. This 5' DNA site is located between the N-terminal BRCT domain and AAA+ module of the large Rfc1 subunit. Our structures reveal ideal binding to a 7-nt gap, which includes 2 bp unwound by the clamp loader. Biochemical studies show enhanced binding to 5 and 10 nt gaps, consistent with the structural results. Because both 3' and 5' ends are present at a ssDNA gap, we propose that the 5' site facilitates RFC's PCNA loading activity at a DNA damage-induced gap to recruit gap-filling polymerases. These findings are consistent with genetic studies showing that base excision repair of gaps greater than 1 base requires PCNA and involves the 5' DNA binding domain of Rfc1. We further observe that a 5' end facilitates PCNA loading at an RPA coated 30-nt gap, suggesting a potential role of the RFC 5'-DNA site in lagging strand DNA synthesis.
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Affiliation(s)
- Fengwei Zheng
- Department of Structural Biology, Van Andel Institute, Grand Rapids, United States
| | - Roxana E Georgescu
- DNA Replication Laboratory, Rockefeller University, New York, United States
| | - Nina Y Yao
- DNA Replication Laboratory, Rockefeller University, New York, United States
| | - Huilin Li
- Department of Structural Biology, Van Andel Institute, Grand Rapids, United States
| | - Michael E O'Donnell
- Howard Hughes Medical Institute, Rockefeller University, New York, United States
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11
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Ryu E, Ha NY, Jung W, Yoo J, Myung K, Kang S. Distinct Motifs in ATAD5 C-Terminal Domain Modulate PCNA Unloading Process. Cells 2022; 11:cells11111832. [PMID: 35681528 PMCID: PMC9180478 DOI: 10.3390/cells11111832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 05/23/2022] [Accepted: 05/30/2022] [Indexed: 12/10/2022] Open
Abstract
Proliferating cell nuclear antigen (PCNA) is a DNA clamp that functions in key roles for DNA replication and repair. After the completion of DNA synthesis, PCNA should be unloaded from DNA in a timely way. The ATAD5-RFC-Like Complex (ATAD5-RLC) unloads PCNA from DNA. However, the mechanism of the PCNA-unloading process remains unclear. In this study, we determined the minimal PCNA-unloading domain (ULD) of ATAD5. We identified several motifs in the ATAD5 ULD that are essential in the PCNA-unloading process. The C-terminus of ULD is required for the stable association of RFC2-5 for active RLC formation. The N-terminus of ULD participates in the opening of the PCNA ring. ATAD5-RLC was more robustly bound to open-liable PCNA compared to the wild type. These results suggest that distinct motifs of the ATAD5 ULD participate in each step of the PCNA-unloading process.
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Affiliation(s)
- Eunjin Ryu
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Korea; (E.R.); (N.Y.H.); (W.J.); (J.Y.); (K.M.)
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan 44919, Korea
| | - Na Young Ha
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Korea; (E.R.); (N.Y.H.); (W.J.); (J.Y.); (K.M.)
| | - Woojae Jung
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Korea; (E.R.); (N.Y.H.); (W.J.); (J.Y.); (K.M.)
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan 44919, Korea
| | - Juyeong Yoo
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Korea; (E.R.); (N.Y.H.); (W.J.); (J.Y.); (K.M.)
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan 44919, Korea
| | - Kyungjae Myung
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Korea; (E.R.); (N.Y.H.); (W.J.); (J.Y.); (K.M.)
- Department of Biomedical Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, Korea
| | - Sukhyun Kang
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Korea; (E.R.); (N.Y.H.); (W.J.); (J.Y.); (K.M.)
- Correspondence:
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12
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Mechanisms of loading and release of the 9-1-1 checkpoint clamp. Nat Struct Mol Biol 2022; 29:369-375. [PMID: 35314831 DOI: 10.1038/s41594-022-00741-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 02/09/2022] [Indexed: 01/14/2023]
Abstract
Single-stranded or double-stranded DNA junctions with recessed 5' ends serve as loading sites for the checkpoint clamp, 9-1-1, which mediates activation of the apical checkpoint kinase, ATRMec1. However, the basis for 9-1-1's recruitment to 5' junctions is unclear. Here, we present structures of the yeast checkpoint clamp loader, Rad24-replication factor C (RFC), in complex with 9-1-1 and a 5' junction and in a post-ATP-hydrolysis state. Unexpectedly, 9-1-1 adopts both closed and planar open states in the presence of Rad24-RFC and DNA. Moreover, Rad24-RFC associates with the DNA junction in the opposite orientation of processivity clamp loaders with Rad24 exclusively coordinating the double-stranded region. ATP hydrolysis stimulates conformational changes in Rad24-RFC, leading to disengagement of DNA-loaded 9-1-1. Together, these structures explain 9-1-1's recruitment to 5' junctions and reveal new principles of sliding clamp loading.
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13
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The partner-swapping sliding clamp loader exposed. Nat Struct Mol Biol 2022; 29:283-286. [PMID: 35410371 DOI: 10.1038/s41594-022-00761-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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14
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van Schie JJM, de Lange J. The Interplay of Cohesin and the Replisome at Processive and Stressed DNA Replication Forks. Cells 2021; 10:3455. [PMID: 34943967 PMCID: PMC8700348 DOI: 10.3390/cells10123455] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 12/04/2021] [Accepted: 12/06/2021] [Indexed: 12/12/2022] Open
Abstract
The cohesin complex facilitates faithful chromosome segregation by pairing the sister chromatids after DNA replication until mitosis. In addition, cohesin contributes to proficient and error-free DNA replication. Replisome progression and establishment of sister chromatid cohesion are intimately intertwined processes. Here, we review how the key factors in DNA replication and cohesion establishment cooperate in unperturbed conditions and during DNA replication stress. We discuss the detailed molecular mechanisms of cohesin recruitment and the entrapment of replicated sister chromatids at the replisome, the subsequent stabilization of sister chromatid cohesion via SMC3 acetylation, as well as the role and regulation of cohesin in the response to DNA replication stress.
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Affiliation(s)
- Janne J. M. van Schie
- Cancer Center Amsterdam, Department of Human Genetics, Section Oncogenetics, Amsterdam University Medical Centers, De Boelelaan 1118, 1081 HV Amsterdam, The Netherlands
| | - Job de Lange
- Cancer Center Amsterdam, Department of Human Genetics, Section Oncogenetics, Amsterdam University Medical Centers, De Boelelaan 1118, 1081 HV Amsterdam, The Netherlands
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15
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Park SH, Kim Y, Ra JS, Wie MW, Kang MS, Kang S, Myung K, Lee KY. Timely termination of repair DNA synthesis by ATAD5 is important in oxidative DNA damage-induced single-strand break repair. Nucleic Acids Res 2021; 49:11746-11764. [PMID: 34718749 PMCID: PMC8599757 DOI: 10.1093/nar/gkab999] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 10/06/2021] [Accepted: 10/12/2021] [Indexed: 12/15/2022] Open
Abstract
Reactive oxygen species (ROS) generate oxidized bases and single-strand breaks (SSBs), which are fixed by base excision repair (BER) and SSB repair (SSBR), respectively. Although excision and repair of damaged bases have been extensively studied, the function of the sliding clamp, proliferating cell nuclear antigen (PCNA), including loading/unloading, remains unclear. We report that, in addition to PCNA loading by replication factor complex C (RFC), timely PCNA unloading by the ATPase family AAA domain-containing protein 5 (ATAD5)-RFC-like complex is important for the repair of ROS-induced SSBs. We found that PCNA was loaded at hydrogen peroxide (H2O2)-generated direct SSBs after the 3'-terminus was converted to the hydroxyl moiety by end-processing enzymes. However, PCNA loading rarely occurred during BER of oxidized or alkylated bases. ATAD5-depleted cells were sensitive to acute H2O2 treatment but not methyl methanesulfonate treatment. Unexpectedly, when PCNA remained on DNA as a result of ATAD5 depletion, H2O2-induced repair DNA synthesis increased in cancerous and normal cells. Based on higher H2O2-induced DNA breakage and SSBR protein enrichment by ATAD5 depletion, we propose that extended repair DNA synthesis increases the likelihood of DNA polymerase stalling, shown by increased PCNA monoubiquitination, and consequently, harmful nick structures are more frequent.
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Affiliation(s)
- Su Hyung Park
- Center for Genomic Integrity, Institute for Basic Science (IBS), Ulsan 44919, Republic of Korea
| | - Youyoung Kim
- Center for Genomic Integrity, Institute for Basic Science (IBS), Ulsan 44919, Republic of Korea.,Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Jae Sun Ra
- Center for Genomic Integrity, Institute for Basic Science (IBS), Ulsan 44919, Republic of Korea
| | - Min Woo Wie
- Center for Genomic Integrity, Institute for Basic Science (IBS), Ulsan 44919, Republic of Korea.,Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Mi-Sun Kang
- Center for Genomic Integrity, Institute for Basic Science (IBS), Ulsan 44919, Republic of Korea
| | - Sukhyun Kang
- Center for Genomic Integrity, Institute for Basic Science (IBS), Ulsan 44919, Republic of Korea
| | - Kyungjae Myung
- Center for Genomic Integrity, Institute for Basic Science (IBS), Ulsan 44919, Republic of Korea.,Department of Biomedical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Kyoo-Young Lee
- Center for Genomic Integrity, Institute for Basic Science (IBS), Ulsan 44919, Republic of Korea
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16
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PCNA Loaders and Unloaders-One Ring That Rules Them All. Genes (Basel) 2021; 12:genes12111812. [PMID: 34828416 PMCID: PMC8618651 DOI: 10.3390/genes12111812] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 11/15/2021] [Accepted: 11/17/2021] [Indexed: 12/23/2022] Open
Abstract
During each cell duplication, the entirety of the genomic DNA in every cell must be accurately and quickly copied. Given the short time available for the chore, the requirement of many proteins, and the daunting amount of DNA present, DNA replication poses a serious challenge to the cell. A high level of coordination between polymerases and other DNA and chromatin-interacting proteins is vital to complete this task. One of the most important proteins for maintaining such coordination is PCNA. PCNA is a multitasking protein that forms a homotrimeric ring that encircles the DNA. It serves as a processivity factor for DNA polymerases and acts as a landing platform for different proteins interacting with DNA and chromatin. Therefore, PCNA is a signaling hub that influences the rate and accuracy of DNA replication, regulates DNA damage repair, controls chromatin formation during the replication, and the proper segregation of the sister chromatids. With so many essential roles, PCNA recruitment and turnover on the chromatin is of utmost importance. Three different, conserved protein complexes are in charge of loading/unloading PCNA onto DNA. Replication factor C (RFC) is the canonical complex in charge of loading PCNA during the S-phase. The Ctf18 and Elg1 (ATAD5 in mammalian) proteins form complexes similar to RFC, with particular functions in the cell’s nucleus. Here we summarize our current knowledge about the roles of these important factors in yeast and mammals.
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17
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Park SH, Kim SJ, Myung K, Lee KY. Characterization of subcellular localization of eukaryotic clamp loader/unloader and its regulatory mechanism. Sci Rep 2021; 11:21817. [PMID: 34751190 PMCID: PMC8575788 DOI: 10.1038/s41598-021-01336-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 10/13/2021] [Indexed: 11/27/2022] Open
Abstract
Proliferating cell nuclear antigen (PCNA) plays a critical role as a processivity clamp for eukaryotic DNA polymerases and a binding platform for many DNA replication and repair proteins. The enzymatic activities of PCNA loading and unloading have been studied extensively in vitro. However, the subcellular locations of PCNA loaders, replication complex C (RFC) and CTF18-RFC-like-complex (RLC), and PCNA unloader ATAD5-RLC remain elusive, and the role of their subunits RFC2-5 is unknown. Here we used protein fractionation to determine the subcellular localization of RFC and RLCs and affinity purification to find molecular requirements for the newly defined location. All RFC/RLC proteins were detected in the nuclease-resistant pellet fraction. RFC1 and ATAD5 were not detected in the non-ionic detergent-soluble and nuclease-susceptible chromatin fractions, independent of cell cycle or exogenous DNA damage. We found that small RFC proteins contribute to maintaining protein levels of the RFC/RLCs. RFC1, ATAD5, and RFC4 co-immunoprecipitated with lamina-associated polypeptide 2 (LAP2) α which regulates intranuclear lamin A/C. LAP2α knockout consistently reduced detection of RFC/RLCs in the pellet fraction, while marginally affecting total protein levels. Our findings strongly suggest that PCNA-mediated DNA transaction occurs through regulatory machinery associated with nuclear structures, such as the nuclear matrix.
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Affiliation(s)
- Su Hyung Park
- Center for Genomic Integrity, Institute for Basic Science, Ulsan, 44919, Korea
| | - Seong-Jung Kim
- Center for Genomic Integrity, Institute for Basic Science, Ulsan, 44919, Korea.,Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan, 44919, Korea
| | - Kyungjae Myung
- Center for Genomic Integrity, Institute for Basic Science, Ulsan, 44919, Korea.,Department of Biomedical Engineering, Ulsan National Institute of Science and Technology, Ulsan, 44919, Korea
| | - Kyoo-Young Lee
- Center for Genomic Integrity, Institute for Basic Science, Ulsan, 44919, Korea.
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18
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Yau TY, Sander W, Eidson C, Courey AJ. SUMO Interacting Motifs: Structure and Function. Cells 2021; 10:cells10112825. [PMID: 34831049 PMCID: PMC8616421 DOI: 10.3390/cells10112825] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 10/14/2021] [Accepted: 10/14/2021] [Indexed: 11/16/2022] Open
Abstract
Small ubiquitin-related modifier (SUMO) is a member of the ubiquitin-related protein family. SUMO modulates protein function through covalent conjugation to lysine residues in a large number of proteins. Once covalently conjugated to a protein, SUMO often regulates that protein’s function by recruiting other cellular proteins. Recruitment frequently involves a non-covalent interaction between SUMO and a SUMO-interacting motif (SIM) in the interacting protein. SIMs generally consist of a four-residue-long hydrophobic stretch of amino acids with aliphatic non-polar side chains flanked on one side by negatively charged amino acid residues. The SIM assumes an extended β-strand-like conformation and binds to a conserved hydrophobic groove in SUMO. In addition to hydrophobic interactions between the SIM non-polar core and hydrophobic residues in the groove, the negatively charged residues in the SIM make favorable electrostatic contacts with positively charged residues in and around the groove. The SIM/SUMO interaction can be regulated by the phosphorylation of residues adjacent to the SIM hydrophobic core, which provide additional negative charges for favorable electrostatic interaction with SUMO. The SUMO interactome consists of hundreds or perhaps thousands of SIM-containing proteins, but we do not fully understand how each SUMOylated protein selects the set of SIM-containing proteins appropriate to its function. SIM/SUMO interactions have critical functions in a large number of essential cellular processes including the formation of membraneless organelles by liquid–liquid phase separation, epigenetic regulation of transcription through histone modification, DNA repair, and a variety of host–pathogen interactions.
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19
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Kawasumi R, Abe T, Psakhye I, Miyata K, Hirota K, Branzei D. Vertebrate CTF18 and DDX11 essential function in cohesion is bypassed by preventing WAPL-mediated cohesin release. Genes Dev 2021; 35:1368-1382. [PMID: 34503989 PMCID: PMC8494208 DOI: 10.1101/gad.348581.121] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 08/16/2021] [Indexed: 01/26/2023]
Abstract
The alternative PCNA loader containing CTF18-DCC1-CTF8 facilitates sister chromatid cohesion (SCC) by poorly defined mechanisms. Here we found that in DT40 cells, CTF18 acts complementarily with the Warsaw breakage syndrome DDX11 helicase in mediating SCC and proliferation. We uncover that the lethality and cohesion defects of ctf18 ddx11 mutants are associated with reduced levels of chromatin-bound cohesin and rescued by depletion of WAPL, a cohesin-removal factor. On the contrary, high levels of ESCO1/2 acetyltransferases that acetylate cohesin to establish SCC do not rescue ctf18 ddx11 phenotypes. Notably, the tight proximity of sister centromeres and increased anaphase bridges characteristic of WAPL-depleted cells are abrogated by loss of both CTF18 and DDX11 The results reveal that vertebrate CTF18 and DDX11 collaborate to provide sufficient amounts of chromatin-loaded cohesin available for SCC generation in the presence of WAPL-mediated cohesin-unloading activity. This process modulates chromosome structure and is essential for cellular proliferation in vertebrates.
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Affiliation(s)
- Ryotaro Kawasumi
- International Foundation of Medicine (IFOM), the Fondazione Italiana per la Ricerca sul Cancro (FIRC) Institute for Molecular Oncology Foundation, Milan 20139, Italy
| | - Takuya Abe
- International Foundation of Medicine (IFOM), the Fondazione Italiana per la Ricerca sul Cancro (FIRC) Institute for Molecular Oncology Foundation, Milan 20139, Italy
- Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, Hachioji-shi, Tokyo 192-0397, Japan
| | - Ivan Psakhye
- International Foundation of Medicine (IFOM), the Fondazione Italiana per la Ricerca sul Cancro (FIRC) Institute for Molecular Oncology Foundation, Milan 20139, Italy
| | - Keiji Miyata
- Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, Hachioji-shi, Tokyo 192-0397, Japan
| | - Kouji Hirota
- Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, Hachioji-shi, Tokyo 192-0397, Japan
| | - Dana Branzei
- International Foundation of Medicine (IFOM), the Fondazione Italiana per la Ricerca sul Cancro (FIRC) Institute for Molecular Oncology Foundation, Milan 20139, Italy
- Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche (IGM-CNR), Pavia 27100, Italy
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20
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Qiu S, Jiang G, Cao L, Huang J. Replication Fork Reversal and Protection. Front Cell Dev Biol 2021; 9:670392. [PMID: 34041245 PMCID: PMC8141627 DOI: 10.3389/fcell.2021.670392] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Accepted: 04/19/2021] [Indexed: 12/12/2022] Open
Abstract
During genome replication, replication forks often encounter obstacles that impede their progression. Arrested forks are unstable structures that can give rise to collapse and rearrange if they are not properly processed and restarted. Replication fork reversal is a critical protective mechanism in higher eukaryotic cells in response to replication stress, in which forks reverse their direction to form a Holliday junction-like structure. The reversed replication forks are protected from nuclease degradation by DNA damage repair proteins, such as BRCA1, BRCA2, and RAD51. Some of these molecules work cooperatively, while others have unique functions. Once the stress is resolved, the replication forks can restart with the help of enzymes, including human RECQ1 helicase, but restart will not be considered here. Here, we review research on the key factors and mechanisms required for the remodeling and protection of stalled replication forks in mammalian cells.
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Affiliation(s)
- Shan Qiu
- Department of General Surgery, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China.,The MOE Key Laboratory of Biosystems Homeostasis and Protection, Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, China.,Zhejiang University-University of Edinburgh Institute, Zhejiang University School of Medicine, Zhejiang University, Haining, China
| | - Guixing Jiang
- Department of General Surgery, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Liping Cao
- Department of General Surgery, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Jun Huang
- Department of General Surgery, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China.,The MOE Key Laboratory of Biosystems Homeostasis and Protection, Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology and Innovation Center for Cell Signaling Network, Life Sciences Institute, Zhejiang University, Hangzhou, China
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