1
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Xu J, Bradley N, He Y. Structure and function of the apical PIKKs in double-strand break repair. Curr Opin Struct Biol 2023; 82:102651. [PMID: 37437397 PMCID: PMC10530350 DOI: 10.1016/j.sbi.2023.102651] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 06/15/2023] [Accepted: 06/16/2023] [Indexed: 07/14/2023]
Abstract
Members of the phosphatidylinositol 3' kinase (PI3K)-related kinases (PIKKs) family, including DNA-dependent protein kinase catalytic subunit (DNA-PKcs), ataxia telangiectasia mutated (ATM), ataxia-telangiectasia mutated and Rad3-related (ATR), mammalian target of rapamycin (mTOR), suppressor with morphological effect on genitalia 1 (SMG1), and transformation/transcription domain-associated protein 1 (TRRAP/Tra1), participate in a variety of physiological processes, such as cell-cycle control, metabolism, transcription, replication, and the DNA damage response. In eukaryotic cells, DNA-PKcs, ATM, and ATR-ATRIP are the main sensors and regulators of DNA double-strand break repair. The purpose of this review is to describe recent structures of DNA-PKcs, ATM, and ATR, as well as their functions in activation and phosphorylation in different DNA repair pathways.
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Affiliation(s)
- Jingfei Xu
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, USA
| | - Noah Bradley
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, USA
| | - Yuan He
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, USA.
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2
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Howes AC, Perisic O, Williams RL. Structural insights into the activation of ataxia-telangiectasia mutated by oxidative stress. SCIENCE ADVANCES 2023; 9:eadi8291. [PMID: 37756394 PMCID: PMC10530080 DOI: 10.1126/sciadv.adi8291] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2023] [Accepted: 08/24/2023] [Indexed: 09/29/2023]
Abstract
Ataxia-telangiectasia mutated (ATM) is a master kinase regulating DNA damage response that is activated by DNA double-strand breaks. However, ATM is also directly activated by reactive oxygen species, but how oxidative activation is achieved remains unknown. We determined the cryo-EM structure of an H2O2-activated ATM and showed that under oxidizing conditions, ATM formed an intramolecular disulfide bridge between two protomers that are rotated relative to each other when compared to the basal state. This rotation is accompanied by release of the substrate-blocking PRD region and twisting of the N-lobe relative to the C-lobe, which greatly optimizes catalysis. This active site remodeling enabled us to capture a substrate (p53) bound to the enzyme. This provides the first structural insights into how ATM is activated during oxidative stress.
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Affiliation(s)
| | - Olga Perisic
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
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3
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Yates L, Tannous E, Morgan R, Burgers P, Zhang X. A DNA damage-induced phosphorylation circuit enhances Mec1 ATR Ddc2 ATRIP recruitment to Replication Protein A. Proc Natl Acad Sci U S A 2023; 120:e2300150120. [PMID: 36996117 PMCID: PMC10083555 DOI: 10.1073/pnas.2300150120] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 02/24/2023] [Indexed: 03/31/2023] Open
Abstract
The cell cycle checkpoint kinase Mec1ATR and its integral partner Ddc2ATRIP are vital for the DNA damage and replication stress response. Mec1-Ddc2 "senses" single-stranded DNA (ssDNA) by being recruited to the ssDNA binding Replication Protein A (RPA) via Ddc2. In this study, we show that a DNA damage-induced phosphorylation circuit modulates checkpoint recruitment and function. We demonstrate that Ddc2-RPA interactions modulate the association between RPA and ssDNA and that Rfa1-phosphorylation aids in the further recruitment of Mec1-Ddc2. We also uncover an underappreciated role for Ddc2 phosphorylation that enhances its recruitment to RPA-ssDNA that is important for the DNA damage checkpoint in yeast. The crystal structure of a phosphorylated Ddc2 peptide in complex with its RPA interaction domain provides molecular details of how checkpoint recruitment is enhanced, which involves Zn2+. Using electron microscopy and structural modeling approaches, we propose that Mec1-Ddc2 complexes can form higher order assemblies with RPA when Ddc2 is phosphorylated. Together, our results provide insight into Mec1 recruitment and suggest that formation of supramolecular complexes of RPA and Mec1-Ddc2, modulated by phosphorylation, would allow for rapid clustering of damage foci to promote checkpoint signaling.
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Affiliation(s)
- Luke A. Yates
- Section of Structural Biology, Department of Infectious Disease, Imperial College London, South Kensington, LondonSW7 2AZ, United Kingdom
| | - Elias A. Tannous
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, Saint Louis, MO63110
| | - R. Marc Morgan
- Department of Life Sciences, Centre for Structural Biology, Imperial College London, South Kensington, LondonSW7 2AZ, United Kingdom
| | - Peter M. Burgers
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, Saint Louis, MO63110
| | - Xiaodong Zhang
- Section of Structural Biology, Department of Infectious Disease, Imperial College London, South Kensington, LondonSW7 2AZ, United Kingdom
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4
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García MEG, Kirsch DG, Reitman ZJ. Targeting the ATM Kinase to Enhance the Efficacy of Radiotherapy and Outcomes for Cancer Patients. Semin Radiat Oncol 2022; 32:3-14. [PMID: 34861994 PMCID: PMC8647772 DOI: 10.1016/j.semradonc.2021.09.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Targeting the DNA damage response represents a promising approach to improve the efficacy of radiation therapy. One appealing target for this approach is the serine/threonine kinase ataxia telangiectasia mutated (ATM), which is activated by DNA double strand breaks to orchestrate the cellular response to ionizing radiation. Small-molecule inhibitors targeting ATM have entered clinical trials testing their safety in combination with radiation therapy or in combination with other DNA damaging agents. Here, we review biochemical, genetic, and cellular functional studies of ATM, phenotypes associated with germline and somatic cancer mutations in ATM in humans, and experiments in genetically engineered mouse models that support a rationale for investigating ATM inhibitors as radiosensitizers for cancer therapy. These data identify important synthetic lethal relationships, which suggest that ATM inhibitors may be particularly effective in tumors with defects in other nodes of the DNA damage response. The potential for ATM inhibition to improve immunotherapy responses in preclinical models represents another emerging area of research. We summarize ongoing clinical trials of ATM inhibitors with radiotherapy. We also discuss critical ongoing areas of investigation that include discovery of biomarkers that predict for radiosensitization by ATM inhibitors and identification of effective combinations of ATM inhibitors, radiation therapy, other DNA damage response-directed therapies, and/or immunotherapies.
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Affiliation(s)
| | - David G Kirsch
- Department of Radiation Oncology, Duke University School of Medicine, Durham NC; Department of Pharmacology & Cancer Biology, Duke University School of Medicine, Durham NC
| | - Zachary J Reitman
- Department of Radiation Oncology, Duke University School of Medicine, Durham NC; The Preston Robert Tisch Brain Tumor Center at Duke University Medical Center, Durham NC.
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5
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Molecular basis of human ATM kinase inhibition. Nat Struct Mol Biol 2021; 28:789-798. [PMID: 34556870 DOI: 10.1038/s41594-021-00654-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 07/30/2021] [Indexed: 12/15/2022]
Abstract
Human checkpoint kinase ataxia telangiectasia-mutated (ATM) plays a key role in initiation of the DNA damage response following DNA double-strand breaks. ATM inhibition is a promising approach in cancer therapy, but, so far, detailed insights into the binding modes of known ATM inhibitors have been hampered due to the lack of high-resolution ATM structures. Using cryo-EM, we have determined the structure of human ATM to an overall resolution sufficient to build a near-complete atomic model and identify two hitherto unknown zinc-binding motifs. We determined the structure of the kinase domain bound to ATPγS and to the ATM inhibitors KU-55933 and M4076 at 2.8 Å, 2.8 Å and 3.0 Å resolution, respectively. The mode of action and selectivity of the ATM inhibitors can be explained by structural comparison and provide a framework for structure-based drug design.
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6
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Tannous EA, Burgers PM. Novel insights into the mechanism of cell cycle kinases Mec1(ATR) and Tel1(ATM). Crit Rev Biochem Mol Biol 2021; 56:441-454. [PMID: 34151669 DOI: 10.1080/10409238.2021.1925218] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
DNA replication is a highly precise process which usually functions in a perfect rhythm with cell cycle progression. However, cells are constantly faced with various kinds of obstacles such as blocks in DNA replication, lack of availability of precursors and improper chromosome alignment. When these problems are not addressed, they may lead to chromosome instability and the accumulation of mutations, and even cell death. Therefore, the cell has developed response mechanisms to keep most of these situations under control. Of the many factors that participate in this DNA damage response, members of the family of phosphatidylinositol 3-kinase-related protein kinases (PIKKs) orchestrate the response landscape. Our understanding of two members of the PIKK family, human ATR (yeast Mec1) and ATM (yeast Tel1), and their associated partner proteins, has shown substantial progress through recent biochemical and structural studies. Emerging structural information of these unique kinases show common features that reveal the mechanism of kinase activity.
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Affiliation(s)
- Elias A Tannous
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, Saint Louis, MO, USA
| | - Peter M Burgers
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, Saint Louis, MO, USA
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7
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Thada V, Cortez D. ATR activation is regulated by dimerization of ATR activating proteins. J Biol Chem 2021; 296:100455. [PMID: 33636182 PMCID: PMC7994790 DOI: 10.1016/j.jbc.2021.100455] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 02/17/2021] [Accepted: 02/22/2021] [Indexed: 02/06/2023] Open
Abstract
The checkpoint kinase ATR regulates DNA repair, cell cycle progression, and other DNA damage and replication stress responses. ATR signaling is stimulated by an ATR activating protein, and in metazoan cells, there are at least two ATR activators: TOPBP1 and ETAA1. Current evidence indicates TOPBP1 and ETAA1 activate ATR via the same biochemical mechanism, but several aspects of this mechanism remain undefined. For example, ATR and its obligate binding partner ATR interacting protein (ATRIP) form a tetrameric complex consisting of two ATR and two ATRIP molecules, but whether TOPBP1 or ETAA1 dimerization is similarly required for ATR function is unclear. Here, we show that fusion of the TOPBP1 and ETAA1 ATR activation domains (AADs) to dimeric tags makes them more potent activators of ATR in vitro. Furthermore, induced dimerization of both AADs using chemical dimerization of a modified FKBP tag enhances ATR kinase activation and signaling in cells. ETAA1 forms oligomeric complexes mediated by regions of the protein that are predicted to be intrinsically disordered. Induced dimerization of a “mini-ETAA1” protein that contains the AAD and Replication Protein A (RPA) interaction motifs enhances ATR signaling, rescues cellular hypersensitivity to DNA damaging agents, and suppresses micronuclei formation in ETAA1-deficient cells. Together, our results indicate that TOPBP1 and ETAA1 dimerization is important for optimal ATR signaling and genome stability.
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Affiliation(s)
- Vaughn Thada
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville Tennessee, USA
| | - David Cortez
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville Tennessee, USA.
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8
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Tannous EA, Yates LA, Zhang X, Burgers PM. Mechanism of auto-inhibition and activation of Mec1 ATR checkpoint kinase. Nat Struct Mol Biol 2020; 28:50-61. [PMID: 33169019 PMCID: PMC7855233 DOI: 10.1038/s41594-020-00522-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 09/24/2020] [Indexed: 01/01/2023]
Abstract
In response to DNA damage or replication fork stalling, the basal activity of Mec1ATR is stimulated in a cell-cycle-dependent manner, leading to cell-cycle arrest and the promotion of DNA repair. Mec1ATR dysfunction leads to cell death in yeast and causes chromosome instability and embryonic lethality in mammals. Thus, ATR is a major target for cancer therapies in homologous recombination-deficient cancers. Here we identify a single mutation in Mec1, conserved in ATR, that results in constitutive activity. Using cryo-electron microscopy, we determine the structures of this constitutively active form (Mec1(F2244L)-Ddc2) at 2.8 Å and the wild type at 3.8 Å, both in complex with Mg2+-AMP-PNP. These structures yield a near-complete atomic model for Mec1-Ddc2 and uncover the molecular basis for low basal activity and the conformational changes required for activation. Combined with biochemical and genetic data, we discover key regulatory regions and propose a Mec1 activation mechanism.
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Affiliation(s)
- Elias A Tannous
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, Saint Louis, MO, USA
| | - Luke A Yates
- Section of Structural Biology, Department of Infectious Disease, Imperial College London, South Kensington, London, UK
| | - Xiaodong Zhang
- Section of Structural Biology, Department of Infectious Disease, Imperial College London, South Kensington, London, UK.
| | - Peter M Burgers
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, Saint Louis, MO, USA.
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9
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Memisoglu G, Lanz MC, Eapen VV, Jordan JM, Lee K, Smolka MB, Haber JE. Mec1 ATR Autophosphorylation and Ddc2 ATRIP Phosphorylation Regulates DNA Damage Checkpoint Signaling. Cell Rep 2020; 28:1090-1102.e3. [PMID: 31340146 DOI: 10.1016/j.celrep.2019.06.068] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 02/21/2019] [Accepted: 06/18/2019] [Indexed: 11/26/2022] Open
Abstract
In budding yeast, a single DNA double-strand break (DSB) triggers the activation of Mec1ATR-dependent DNA damage checkpoint. After about 12 h, cells turn off the checkpoint signaling and adapt despite the persistence of the DSB. We report that the adaptation involves the autophosphorylation of Mec1 at site S1964. A non-phosphorylatable mec1-S1964A mutant causes cells to arrest permanently in response to a single DSB without affecting the initial kinase activity of Mec1. Autophosphorylation of S1964 is dependent on Ddc1Rad9 and Dpb11TopBP1, and it correlates with the timing of adaptation. We also report that Mec1's binding partner, Ddc2ATRIP, is an inherently stable protein that is degraded specifically upon DNA damage. Ddc2 is regulated extensively through phosphorylation, which, in turn, regulates the localization of the Mec1-Ddc2 complex to DNA lesions. Taken together, these results suggest that checkpoint response is regulated through the autophosphorylation of Mec1 kinase and through the changes in Ddc2 abundance and phosphorylation.
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Affiliation(s)
- Gonen Memisoglu
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454, USA
| | - Michael C Lanz
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA
| | - Vinay V Eapen
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454, USA; Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Jacqueline M Jordan
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454, USA
| | - Kihoon Lee
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454, USA; Seegene, Inc., Ogeum-ro, Songpa-gu, Seoul 05548, Korea
| | - Marcus B Smolka
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA
| | - James E Haber
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454, USA.
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10
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Williams RM, Yates LA, Zhang X. Structures and regulations of ATM and ATR, master kinases in genome integrity. Curr Opin Struct Biol 2020; 61:98-105. [PMID: 31924595 DOI: 10.1016/j.sbi.2019.12.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 11/27/2019] [Accepted: 12/07/2019] [Indexed: 12/24/2022]
Abstract
Homologous recombination (HR) is a faithful repair mechanism for double stranded DNA breaks. Two highly homologous master kinases, the tumour suppressors ATM and ATR (Tel1 and Mec1 in yeast), coordinate cell cycle progression with repair during HR. Despite their importance, our molecular understanding of these apical coordinators has been limited, in part due to their large sizes. With the recent development in cryo-electron microscopy, significant advances have been made in structural characterisation of these proteins in the last two years. These structures, combined with new biochemical studies, now provide a more detailed understanding of how a low basal activity is maintained and how activation may occur. In this review, we summarize recent advances in the structural and molecular understanding of these key components in HR, compare the common and distinct features of these kinases and suggest aspects of structural components that are likely to be involved in regulating its activity.
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Affiliation(s)
- Rhys M Williams
- Section of Structural Biology, Faculty of Medicine, Imperial College London, London SW7 2AZ, UK
| | - Luke A Yates
- Section of Structural Biology, Faculty of Medicine, Imperial College London, London SW7 2AZ, UK
| | - Xiaodong Zhang
- Section of Structural Biology, Faculty of Medicine, Imperial College London, London SW7 2AZ, UK.
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11
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Sun Y, McCorvie TJ, Yates LA, Zhang X. Structural basis of homologous recombination. Cell Mol Life Sci 2020; 77:3-18. [PMID: 31748913 PMCID: PMC6957567 DOI: 10.1007/s00018-019-03365-1] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 10/10/2019] [Accepted: 10/31/2019] [Indexed: 12/12/2022]
Abstract
Homologous recombination (HR) is a pathway to faithfully repair DNA double-strand breaks (DSBs). At the core of this pathway is a DNA recombinase, which, as a nucleoprotein filament on ssDNA, pairs with homologous DNA as a template to repair the damaged site. In eukaryotes Rad51 is the recombinase capable of carrying out essential steps including strand invasion, homology search on the sister chromatid and strand exchange. Importantly, a tightly regulated process involving many protein factors has evolved to ensure proper localisation of this DNA repair machinery and its correct timing within the cell cycle. Dysregulation of any of the proteins involved can result in unchecked DNA damage, leading to uncontrolled cell division and cancer. Indeed, many are tumour suppressors and are key targets in the development of new cancer therapies. Over the past 40 years, our structural and mechanistic understanding of homologous recombination has steadily increased with notable recent advancements due to the advances in single particle cryo electron microscopy. These have resulted in higher resolution structural models of the signalling proteins ATM (ataxia telangiectasia mutated), and ATR (ataxia telangiectasia and Rad3-related protein), along with various structures of Rad51. However, structural information of the other major players involved, such as BRCA1 (breast cancer type 1 susceptibility protein) and BRCA2 (breast cancer type 2 susceptibility protein), has been limited to crystal structures of isolated domains and low-resolution electron microscopy reconstructions of the full-length proteins. Here we summarise the current structural understanding of homologous recombination, focusing on key proteins in recruitment and signalling events as well as the mediators for the Rad51 recombinase.
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Affiliation(s)
- Yueru Sun
- Section of Structural Biology, Department of Infectious Diseases, Imperial College, London, SW7 2AZ, UK
| | - Thomas J McCorvie
- Section of Structural Biology, Department of Infectious Diseases, Imperial College, London, SW7 2AZ, UK
| | - Luke A Yates
- Section of Structural Biology, Department of Infectious Diseases, Imperial College, London, SW7 2AZ, UK
| | - Xiaodong Zhang
- Section of Structural Biology, Department of Infectious Diseases, Imperial College, London, SW7 2AZ, UK.
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12
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Jansma M, Linke-Winnebeck C, Eustermann S, Lammens K, Kostrewa D, Stakyte K, Litz C, Kessler B, Hopfner KP. Near-Complete Structure and Model of Tel1ATM from Chaetomium thermophilum Reveals a Robust Autoinhibited ATP State. Structure 2019; 28:83-95.e5. [PMID: 31740028 DOI: 10.1016/j.str.2019.10.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 10/02/2019] [Accepted: 10/21/2019] [Indexed: 11/18/2022]
Abstract
Tel1 (ATM in humans) is a large kinase that resides in the cell in an autoinhibited dimeric state and upon activation orchestrates the cellular response to DNA damage. We report the structure of an endogenous Tel1 dimer from Chaetomium thermophilum. Major parts are at 2.8 Å resolution, including the kinase active site with ATPγS bound, and two different N-terminal solenoid conformations are at 3.4 Å and 3.6 Å, providing a side-chain model for 90% of the Tel1 polypeptide. We show that the N-terminal solenoid has DNA binding activity, but that its movements are not coupled to kinase activation. Although ATPγS and catalytic residues are poised for catalysis, the kinase resides in an autoinhibited state. The PIKK regulatory domain acts as a pseudo-substrate, blocking direct access to the site of catalysis. The structure allows mapping of human cancer mutations and defines mechanisms of autoinhibition at near-atomic resolution.
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Affiliation(s)
- Marijke Jansma
- Department of Biochemistry, Ludwig-Maximilians-Universität, Feodor-Lynen-Strasse 25, 81377 Munich, Germany; Gene Center, Ludwig-Maximilians-Universität, Feodor-Lynen-Strasse 25, 81377 Munich, Germany
| | - Christian Linke-Winnebeck
- Department of Biochemistry, Ludwig-Maximilians-Universität, Feodor-Lynen-Strasse 25, 81377 Munich, Germany; Gene Center, Ludwig-Maximilians-Universität, Feodor-Lynen-Strasse 25, 81377 Munich, Germany
| | - Sebastian Eustermann
- Department of Biochemistry, Ludwig-Maximilians-Universität, Feodor-Lynen-Strasse 25, 81377 Munich, Germany; Gene Center, Ludwig-Maximilians-Universität, Feodor-Lynen-Strasse 25, 81377 Munich, Germany
| | - Katja Lammens
- Department of Biochemistry, Ludwig-Maximilians-Universität, Feodor-Lynen-Strasse 25, 81377 Munich, Germany; Gene Center, Ludwig-Maximilians-Universität, Feodor-Lynen-Strasse 25, 81377 Munich, Germany
| | - Dirk Kostrewa
- Department of Biochemistry, Ludwig-Maximilians-Universität, Feodor-Lynen-Strasse 25, 81377 Munich, Germany; Gene Center, Ludwig-Maximilians-Universität, Feodor-Lynen-Strasse 25, 81377 Munich, Germany
| | - Kristina Stakyte
- Department of Biochemistry, Ludwig-Maximilians-Universität, Feodor-Lynen-Strasse 25, 81377 Munich, Germany; Gene Center, Ludwig-Maximilians-Universität, Feodor-Lynen-Strasse 25, 81377 Munich, Germany
| | - Claudia Litz
- Department of Biochemistry, Ludwig-Maximilians-Universität, Feodor-Lynen-Strasse 25, 81377 Munich, Germany; Gene Center, Ludwig-Maximilians-Universität, Feodor-Lynen-Strasse 25, 81377 Munich, Germany
| | - Brigitte Kessler
- Department of Biochemistry, Ludwig-Maximilians-Universität, Feodor-Lynen-Strasse 25, 81377 Munich, Germany; Gene Center, Ludwig-Maximilians-Universität, Feodor-Lynen-Strasse 25, 81377 Munich, Germany
| | - Karl-Peter Hopfner
- Department of Biochemistry, Ludwig-Maximilians-Universität, Feodor-Lynen-Strasse 25, 81377 Munich, Germany; Gene Center, Ludwig-Maximilians-Universität, Feodor-Lynen-Strasse 25, 81377 Munich, Germany.
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13
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Cryo-EM Structure of Nucleotide-Bound Tel1 ATM Unravels the Molecular Basis of Inhibition and Structural Rationale for Disease-Associated Mutations. Structure 2019; 28:96-104.e3. [PMID: 31740029 PMCID: PMC6945111 DOI: 10.1016/j.str.2019.10.012] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 09/05/2019] [Accepted: 10/18/2019] [Indexed: 01/20/2023]
Abstract
Yeast Tel1 and its highly conserved human ortholog ataxia-telangiectasia mutated (ATM) are large protein kinases central to the maintenance of genome integrity. Mutations in ATM are found in ataxia-telangiectasia (A-T) patients and ATM is one of the most frequently mutated genes in many cancers. Using cryoelectron microscopy, we present the structure of Tel1 in a nucleotide-bound state. Our structure reveals molecular details of key residues surrounding the nucleotide binding site and provides a structural and molecular basis for its intrinsically low basal activity. We show that the catalytic residues are in a productive conformation for catalysis, but the phosphatidylinositol 3-kinase-related kinase (PIKK) regulatory domain insert restricts peptide substrate access and the N-lobe is in an open conformation, thus explaining the requirement for Tel1 activation. Structural comparisons with other PIKKs suggest a conserved and common allosteric activation mechanism. Our work also provides a structural rationale for many mutations found in A-T and cancer.
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14
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Baretic D, Maia de Oliveira T, Niess M, Wan P, Pollard H, Johnson CM, Truman C, McCall E, Fisher D, Williams R, Phillips C. Structural insights into the critical DNA damage sensors DNA-PKcs, ATM and ATR. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2019; 147:4-16. [PMID: 31255703 DOI: 10.1016/j.pbiomolbio.2019.06.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 06/24/2019] [Indexed: 12/21/2022]
Abstract
ATM, ATR and DNA-PKCs are key effectors of DNA Damage response and have been extensively linked to tumourigenesis and survival of cancer cells after radio/chemotherapy. Despite numerous efforts, the structures of these proteins remained elusive until very recently. The resolution revolution in Cryo-EM allowed for molecular details of these proteins to be seen for the first time. Here we provide a comprehensive review of the structures of ATM, ATR and DNA-PKcs and their complexes and expand with observations springing from our own cryo-EM studies. These observations include a novel conformation of ATR and novel dimeric arrangements of DNA-PKcs.
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Affiliation(s)
| | | | - Martina Niess
- Discovery Biology, Discovery Sciences, Biopharmaceuticals R&D, Cambridge, UK
| | - Paul Wan
- Discovery Biology, Discovery Sciences, Biopharmaceuticals R&D, Cambridge, UK
| | - Hannah Pollard
- Discovery Biology, Discovery Sciences, Biopharmaceuticals R&D, Cambridge, UK
| | | | - Caroline Truman
- Discovery Biology, Discovery Sciences, Biopharmaceuticals R&D, Cambridge, UK
| | - Eileen McCall
- Discovery Biology, Discovery Sciences, Biopharmaceuticals R&D, Cambridge, UK
| | - David Fisher
- Discovery Biology, Discovery Sciences, Biopharmaceuticals R&D, Cambridge, UK
| | | | - Christopher Phillips
- Structure Biophysics and FBLG, Discovery Sciences, Biopharmaceuticals R&D, Cambridge, UK
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15
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Guo X, Lin W, Bai M, Li H, Wen W, Zeng C, Chen Z, He J, Chen J, Cai Q, Long J, Jia WH, Shu XO, Zheng W. Discovery of a Pathogenic Variant rs139379666 (p. P2974L) in ATM for Breast Cancer Risk in Chinese Populations. Cancer Epidemiol Biomarkers Prev 2019; 28:1308-1315. [PMID: 31160347 DOI: 10.1158/1055-9965.epi-18-1294] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 03/20/2019] [Accepted: 05/28/2019] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Pathogenic variants in susceptibility genes lead to increased breast cancer risk. METHODS To identify coding variants associated with breast cancer risk, we conducted whole-exome sequencing in genomic DNA samples from 831 breast cancer cases and 839 controls of Chinese women. We also genotyped samples, including 4,580 breast cancer cases and 6,695 controls, using whole exome-chip arrays. We further performed a replication study using a Multi-Ethnic Global Array in samples from 1,793 breast cases and 2,059 controls. A single marker analysis was performed using the Fisher exact test. RESULTS We identified a missense variant (rs139379666, P2974L; AF = 0.09% for breast cancer cases, but none for controls) in the ATM gene for breast cancer risk using combing data from 7,204 breast cancer cases and 9,593 controls (P = 1.7 × 10-5). To investigate the functionality of the variant, we first silenced ATM and then transfected the overexpression vectors of ATM containing the risk alleles (TT) or reference alleles (CC) of the variant in U2OS and breast cancer SK-BR3 cells, respectively. Our results showed that compared with the reference allele, the risk allele significantly disrupts the activity of homologous recombination-mediated double-strand breaks repair efficiency. Our results further showed that the risk allele may play a defected regulation role in the activity of the ATM structure. CONCLUSIONS Our findings identified a novel mutation that disrupts ATM function, conferring to breast cancer risk. IMPACT Functional investigation of genetic association findings is necessary to discover a pathogenic variant for breast cancer risk.
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Affiliation(s)
- Xingyi Guo
- Division of Epidemiology, Department of Medicine, Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee.
| | - Weiqiang Lin
- The Kidney Disease Center, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China. .,Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, China
| | - Mengqiu Bai
- The Kidney Disease Center, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, China
| | - Hongzhi Li
- Department of Bioinformatics, Beckman Research Institute of City of Hope, Duarte, California
| | - Wanqing Wen
- Division of Epidemiology, Department of Medicine, Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Chenjie Zeng
- Division of Epidemiology, Department of Medicine, Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Zhishan Chen
- Division of Epidemiology, Department of Medicine, Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Jing He
- Division of Epidemiology, Department of Medicine, Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Jianghua Chen
- Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, China
| | - Qiuyin Cai
- Division of Epidemiology, Department of Medicine, Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Jirong Long
- Division of Epidemiology, Department of Medicine, Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Wei-Hua Jia
- Department of Experimental Research, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-Sen University Cancer Center, Guangzhou, Guangdong, China
| | - Xiao-Ou Shu
- Division of Epidemiology, Department of Medicine, Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Wei Zheng
- Division of Epidemiology, Department of Medicine, Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee
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16
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Hailemariam S, Kumar S, Burgers PM. Activation of Tel1 ATM kinase requires Rad50 ATPase and long nucleosome-free DNA but no DNA ends. J Biol Chem 2019; 294:10120-10130. [PMID: 31073030 DOI: 10.1074/jbc.ra119.008410] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 05/07/2019] [Indexed: 12/13/2022] Open
Abstract
In Saccharomyces cerevisiae, Tel1 protein kinase, the ortholog of human ataxia telangiectasia-mutated (ATM), is activated in response to DNA double-strand breaks. Biochemical studies with human ATM and genetic studies in yeast suggest that recruitment and activation of Tel1ATM depends on the heterotrimeric MRXMRN complex, composed of Mre11, Rad50, and Xrs2 (human Nbs1). However, the mechanism of activation of Tel1 by MRX remains unclear, as does the role of effector DNA. Here we demonstrate that dsDNA and MRX activate Tel1 synergistically. Although minimal activation was observed with 80-mer duplex DNA, the optimal effector for Tel1 activation is long, nucleosome-free DNA. However, there is no requirement for DNA double-stranded termini. The ATPase activity of Rad50 is critical for activation. In addition to DNA and Rad50, either Mre11 or Xrs2, but not both, is also required. Each of the three MRX subunits shows a physical association with Tel1. Our study provides a model of how the individual subunits of MRX and DNA regulate Tel1 kinase activity.
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Affiliation(s)
- Sarem Hailemariam
- From the Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Sandeep Kumar
- From the Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Peter M Burgers
- From the Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri 63110
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17
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Abd Rahim MS, Cherniavskyi YK, Tieleman DP, Dames SA. NMR- and MD simulation-based structural characterization of the membrane-associating FATC domain of ataxia telangiectasia mutated. J Biol Chem 2019; 294:7098-7112. [PMID: 30867195 DOI: 10.1074/jbc.ra119.007653] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 03/08/2019] [Indexed: 12/26/2022] Open
Abstract
The Ser/Thr protein kinase ataxia telangiectasia mutated (ATM) plays an important role in the DNA damage response, signaling in response to redox signals, the control of metabolic processes, and mitochondrial homeostasis. ATM localizes to the nucleus and at the plasma membrane, mitochondria, peroxisomes, and other cytoplasmic vesicular structures. It has been shown that the C-terminal FATC domain of human ATM (hATMfatc) can interact with a range of membrane mimetics and may thereby act as a membrane-anchoring unit. Here, NMR structural and 15N relaxation data, NMR data using spin-labeled micelles, and MD simulations of micelle-associated hATMfatc revealed that it binds the micelle by a dynamic assembly of three helices with many residues of hATMfatc located in the headgroup region. We observed that none of the three helices penetrates the micelle deeply or makes significant tertiary contacts to the other helices. NMR-monitored interaction experiments with hATMfatc variants in which two conserved aromatic residues (Phe3049 and Trp3052) were either individually or both replaced by alanine disclosed that the double substitution does not abrogate the interaction with micelles and bicelles at the high concentrations at which these aggregates are typically used, but impairs interactions with small unilamellar vesicles, usually used at much lower lipid concentrations and considered a better mimetic for natural membranes. We conclude that the observed dynamic structure of micelle-associated hATMfatc may enable it to interact with differently composed membranes or membrane-associated interaction partners and thereby regulate ATM's kinase activity. Moreover, the FATC domain of ATM may function as a membrane-anchoring unit for other biomolecules.
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Affiliation(s)
- Munirah S Abd Rahim
- From the Chair of Biomolecular NMR Spectroscopy, Department of Chemistry, Technische Universität München, Lichtenbergstrasse 4, 85747 Garching, Germany
| | - Yevhen K Cherniavskyi
- the Department of Biological Sciences and Centre for Molecular Simulation, University of Calgary, Calgary, Alberta T2N 1N4, Canada, and
| | - D Peter Tieleman
- the Department of Biological Sciences and Centre for Molecular Simulation, University of Calgary, Calgary, Alberta T2N 1N4, Canada, and
| | - Sonja A Dames
- From the Chair of Biomolecular NMR Spectroscopy, Department of Chemistry, Technische Universität München, Lichtenbergstrasse 4, 85747 Garching, Germany, .,the Institute of Structural Biology, Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany
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18
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Sawicka M, Aramayo R, Ayala R, Glyde R, Zhang X. Single-Particle Electron Microscopy Analysis of DNA Repair Complexes. Methods Enzymol 2018; 592:159-186. [PMID: 28668120 DOI: 10.1016/bs.mie.2017.03.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
DNA repair complexes play crucial roles in maintaining genome integrity, which is essential for the survival of an organism. The understanding of their modes of action is often obscure due to limited structural knowledge. Structural characterizations of these complexes are often challenging due to a poor protein production yield, a conformational flexibility, and a relatively high molecular mass. Single-particle electron microscopy (EM) has been successfully applied to study some of these complexes as it requires low amount of samples, is not limited by the high molecular mass of a protein or a complex, and can separate heterogeneous assemblies. Recently, near-atomic resolution structures have been obtained with EM owing to the advances in technology and image processing algorithms. In this chapter, we review the EM methodology of obtaining three-dimensional reconstructions of macromolecular complexes and provide a workflow that can be applied to DNA repair complex assemblies.
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Affiliation(s)
- Marta Sawicka
- Section of Structural Biology, Imperial College London, South Kensington, London, United Kingdom
| | - Ricardo Aramayo
- Section of Structural Biology, Imperial College London, South Kensington, London, United Kingdom
| | - Rafael Ayala
- Section of Structural Biology, Imperial College London, South Kensington, London, United Kingdom
| | - Robert Glyde
- Section of Structural Biology, Imperial College London, South Kensington, London, United Kingdom
| | - Xiaodong Zhang
- Section of Structural Biology, Imperial College London, South Kensington, London, United Kingdom.
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19
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Ahamad N, Sharma T, Khan S, Siddiqi MI, Ahmed S. Phosphorylation of Wat1, human Lst8 homolog is critical for the regulation of TORC2 –Gad8 dependent pathway in fission yeast Schizosacchromyces pombe. Eur J Cell Biol 2018; 97:300-307. [DOI: 10.1016/j.ejcb.2018.04.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 04/04/2018] [Accepted: 04/16/2018] [Indexed: 12/28/2022] Open
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20
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Imseng S, Aylett CHS, Maier T. Architecture and activation of phosphatidylinositol 3-kinase related kinases. Curr Opin Struct Biol 2018; 49:177-189. [DOI: 10.1016/j.sbi.2018.03.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 03/02/2018] [Accepted: 03/08/2018] [Indexed: 12/23/2022]
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21
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Establishment of the early cilia preassembly protein complex during motile ciliogenesis. Proc Natl Acad Sci U S A 2018; 115:E1221-E1228. [PMID: 29358401 DOI: 10.1073/pnas.1715915115] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Motile cilia are characterized by dynein motor units, which preassemble in the cytoplasm before trafficking into the cilia. Proteins required for dynein preassembly were discovered by finding human mutations that result in absent ciliary motors, but little is known about their expression, function, or interactions. By monitoring ciliogenesis in primary airway epithelial cells and MCIDAS-regulated induced pluripotent stem cells, we uncovered two phases of expression of preassembly proteins. An early phase, composed of HEATR2, SPAG1, and DNAAF2, preceded other preassembly proteins and was independent of MCIDAS regulation. The early preassembly proteins colocalized within perinuclear foci that also contained dynein arm proteins. These proteins also interacted based on immunoprecipitation and Förster resonance energy transfer (FRET) studies. FRET analysis of HEAT domain deletions and human mutations showed that HEATR2 interacted with itself and SPAG1 at multiple HEAT domains, while DNAAF2 interacted with SPAG1. Human mutations in HEATR2 did not affect this interaction, but triggered the formation of p62/Sequestosome-1-positive aggregates containing the early preassembly proteins, suggesting that degradation of an early preassembly complex is responsible for disease and pointing to key regions required for HEATR2 scaffold stability. We speculate that HEATR2 is an early scaffold for the initiation of dynein complex assembly in motile cilia.
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22
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Adamowicz M. Breaking up with ATM. JOURNAL OF IMMUNOLOGICAL SCIENCES 2018; 2:26-31. [PMID: 29652413 PMCID: PMC5892715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
ATM kinase is a master regulator of the DNA damage response (DDR). A recently published report from the d'Adda di Fagagna laboratory1 sheds a light onto our understanding of ATM activation. In this short-commentary we will expand on this and other work to perceive better some of the aspects of ATM regulation.
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Affiliation(s)
- Marek Adamowicz
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RH, UK,Correspondence: Dr. Marek Adamowicz, Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RH, UK;
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23
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Cryo-EM structure of human ATR-ATRIP complex. Cell Res 2017; 28:143-156. [PMID: 29271416 DOI: 10.1038/cr.2017.158] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 12/01/2017] [Accepted: 12/05/2017] [Indexed: 12/18/2022] Open
Abstract
ATR (ataxia telangiectasia-mutated and Rad3-related) protein kinase and ATRIP (ATR-interacting protein) form a complex and play a critical role in response to replication stress and DNA damage. Here, we determined the cryo-electron microscopy (EM) structure of the human ATR-ATRIP complex at 4.7 Å resolution and built an atomic model of the C-terminal catalytic core of ATR (residues 1 521-2 644) at 3.9 Å resolution. The complex adopts a hollow "heart" shape, consisting of two ATR monomers in distinct conformations. The EM map for ATRIP reveals 14 HEAT repeats in an extended "S" shape. The conformational flexibility of ATR allows ATRIP to properly lock the N-termini of the two ATR monomers to favor ATR-ATRIP complex formation and functional diversity. The isolated "head-head" and "tail-tail" each adopts a pseudo 2-fold symmetry. The catalytic pockets face outward and substrate access is not restricted by inhibitory elements. Our studies provide a structural basis for understanding the assembly of the ATR-ATRIP complex and a framework for characterizing ATR-mediated DNA repair pathways.
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24
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Wang X, Ran T, Zhang X, Xin J, Zhang Z, Wu T, Wang W, Cai G. 3.9 Å structure of the yeast Mec1-Ddc2 complex, a homolog of human ATR-ATRIP. Science 2017; 358:1206-1209. [DOI: 10.1126/science.aan8414] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 11/01/2017] [Indexed: 12/12/2022]
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25
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Deshpande I, Seeber A, Shimada K, Keusch JJ, Gut H, Gasser SM. Structural Basis of Mec1-Ddc2-RPA Assembly and Activation on Single-Stranded DNA at Sites of Damage. Mol Cell 2017; 68:431-445.e5. [PMID: 29033322 DOI: 10.1016/j.molcel.2017.09.019] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 08/18/2017] [Accepted: 09/14/2017] [Indexed: 10/18/2022]
Abstract
Mec1-Ddc2 (ATR-ATRIP) is a key DNA-damage-sensing kinase that is recruited through the single-stranded (ss) DNA-binding replication protein A (RPA) to initiate the DNA damage checkpoint response. Activation of ATR-ATRIP in the absence of DNA damage is lethal. Therefore, it is important that damage-specific recruitment precedes kinase activation, which is achieved at least in part by Mec1-Ddc2 homodimerization. Here, we report a structural, biochemical, and functional characterization of the yeast Mec1-Ddc2-RPA assembly. High-resolution co-crystal structures of Ddc2-Rfa1 and Ddc2-Rfa1-t11 (K45E mutant) N termini and of the Ddc2 coiled-coil domain (CCD) provide insight into Mec1-Ddc2 homodimerization and damage-site targeting. Based on our structural and functional findings, we present a Mec1-Ddc2-RPA-ssDNA composite structural model. By way of validation, we show that RPA-dependent recruitment of Mec1-Ddc2 is crucial for maintaining its homodimeric state at ssDNA and that Ddc2's recruitment domain and CCD are important for Mec1-dependent survival of UV-light-induced DNA damage.
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Affiliation(s)
- Ishan Deshpande
- Friedrich Miescher Institute for Biomedical Research (FMI), Maulbeerstrasse 66, 4058 Basel, Switzerland; University of Basel, Faculty of Natural Sciences, Klingelbergstrasse 50, 4056 Basel, Switzerland
| | - Andrew Seeber
- Friedrich Miescher Institute for Biomedical Research (FMI), Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Kenji Shimada
- Friedrich Miescher Institute for Biomedical Research (FMI), Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Jeremy J Keusch
- Friedrich Miescher Institute for Biomedical Research (FMI), Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Heinz Gut
- Friedrich Miescher Institute for Biomedical Research (FMI), Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Susan M Gasser
- Friedrich Miescher Institute for Biomedical Research (FMI), Maulbeerstrasse 66, 4058 Basel, Switzerland; University of Basel, Faculty of Natural Sciences, Klingelbergstrasse 50, 4056 Basel, Switzerland.
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26
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Saldivar JC, Cortez D, Cimprich KA. The essential kinase ATR: ensuring faithful duplication of a challenging genome. Nat Rev Mol Cell Biol 2017; 18:622-636. [PMID: 28811666 DOI: 10.1038/nrm.2017.67] [Citation(s) in RCA: 518] [Impact Index Per Article: 74.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
One way to preserve a rare book is to lock it away from all potential sources of damage. Of course, an inaccessible book is also of little use, and the paper and ink will continue to degrade with age in any case. Like a book, the information stored in our DNA needs to be read, but it is also subject to continuous assault and therefore needs to be protected. In this Review, we examine how the replication stress response that is controlled by the kinase ataxia telangiectasia and Rad3-related (ATR) senses and resolves threats to DNA integrity so that the DNA remains available to read in all of our cells. We discuss the multiple data that have revealed an elegant yet increasingly complex mechanism of ATR activation. This involves a core set of components that recruit ATR to stressed replication forks, stimulate kinase activity and amplify ATR signalling. We focus on the activities of ATR in the control of cell cycle checkpoints, origin firing and replication fork stability, and on how proper regulation of these processes is crucial to ensure faithful duplication of a challenging genome.
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Affiliation(s)
- Joshua C Saldivar
- Department of Chemical and Systems Biology, Stanford University School of Medicine, 318 Campus Drive, Stanford, California 94305-5441, USA
| | - David Cortez
- Department of Biochemistry, School of Medicine, Vanderbilt University, Nashville, Tennessee 37232, USA
| | - Karlene A Cimprich
- Department of Chemical and Systems Biology, Stanford University School of Medicine, 318 Campus Drive, Stanford, California 94305-5441, USA
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27
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Díaz-Santín LM, Lukoyanova N, Aciyan E, Cheung AC. Cryo-EM structure of the SAGA and NuA4 coactivator subunit Tra1 at 3.7 angstrom resolution. eLife 2017; 6:28384. [PMID: 28767037 PMCID: PMC5576489 DOI: 10.7554/elife.28384] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 07/31/2017] [Indexed: 01/30/2023] Open
Abstract
Coactivator complexes SAGA and NuA4 stimulate transcription by post-translationally modifying chromatin. Both complexes contain the Tra1 subunit, a highly conserved 3744-residue protein from the Phosphoinositide 3-Kinase-related kinase (PIKK) family and a direct target for multiple sequence-specific activators. We present the Cryo-EM structure of Saccharomyces cerevsisae Tra1 to 3.7 Å resolution, revealing an extensive network of alpha-helical solenoids organized into a diamond ring conformation and is strikingly reminiscent of DNA-PKcs, suggesting a direct role for Tra1 in DNA repair. The structure was fitted into an existing SAGA EM reconstruction and reveals limited contact surfaces to Tra1, hence it does not act as a molecular scaffold within SAGA. Mutations that affect activator targeting are distributed across the Tra1 structure, but also cluster within the N-terminal Finger region, indicating the presence of an activator interaction site. The structure of Tra1 is a key milestone in deciphering the mechanism of multiple coactivator complexes. Inside our cells, histone proteins package and condense DNA so that it can fit into the cell nucleus. However, this also switches off the genes, since the machines that read and interpret them can no longer access the underlying DNA. Turning genes on requires specific enzymes that chemically modify the histone proteins to regain access to the DNA. This must be carefully controlled, otherwise the ‘wrong’ genes can be activated, causing undesired effects and endangering the cell. Histone modifying enzymes often reside in large protein complexes. Two well-known examples are the SAGA and NuA4 complexes. Both have different roles during gene activation, but share a protein called Tra1. This protein enables SAGA and NuA4 to act on specific genes by binding to ‘activator proteins’ that are found on the DNA. Tra1 is one of the biggest proteins in the cell, but its size makes it difficult to study and until now, its structure was unknown. To determine the structure of Tra1, Díaz-Santín et al. extracted the protein from baker’s yeast, and examined it using electron microscopy. The structure of Tra1 resembled a diamond ring with multiple protein domains that correspond to a band, setting and a centre stone. The structure was detailed enough so that Díaz-Santín et al. could locate various mutations that affect the role of Tra1. These locations are likely to be direct interfaces to the ‘activator proteins’. Moreover, the study showed that Tra1 was similar to another protein that repairs damaged DNA. These results suggest that Tra1 not only works as an activator target, but may also have a role in repairing damaged DNA, and might even connect these two processes. Yeast Tra1 is also very similar to its human counterpart, which has been shown to stimulate cells to become cancerous. Further studies based on these results may help us understand how cancer begins.
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Affiliation(s)
- Luis Miguel Díaz-Santín
- Department of Structural and Molecular Biology, Institute of Structural and Molecular Biology, University College London, London, United Kingdom
| | - Natasha Lukoyanova
- Institute of Structural and Molecular Biology, Biological Sciences, Birkbeck College, London, United Kingdom
| | - Emir Aciyan
- Institute of Structural and Molecular Biology, Biological Sciences, Birkbeck College, London, United Kingdom
| | - Alan Cm Cheung
- Department of Structural and Molecular Biology, Institute of Structural and Molecular Biology, University College London, London, United Kingdom.,Institute of Structural and Molecular Biology, Biological Sciences, Birkbeck College, London, United Kingdom
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28
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Blackford AN, Jackson SP. ATM, ATR, and DNA-PK: The Trinity at the Heart of the DNA Damage Response. Mol Cell 2017; 66:801-817. [PMID: 28622525 DOI: 10.1016/j.molcel.2017.05.015] [Citation(s) in RCA: 1145] [Impact Index Per Article: 163.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 04/28/2017] [Accepted: 05/16/2017] [Indexed: 01/09/2023]
Abstract
In vertebrate cells, the DNA damage response is controlled by three related kinases: ATM, ATR, and DNA-PK. It has been 20 years since the cloning of ATR, the last of the three to be identified. During this time, our understanding of how these kinases regulate DNA repair and associated events has grown profoundly, although major questions remain unanswered. Here, we provide a historical perspective of their discovery and discuss their established functions in sensing and responding to genotoxic stress. We also highlight what is known regarding their structural similarities and common mechanisms of regulation, as well as emerging non-canonical roles and how our knowledge of ATM, ATR, and DNA-PK is being translated to benefit human health.
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Affiliation(s)
- Andrew N Blackford
- Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK; Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford OX3 7DQ, UK; Wellcome Trust and Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK.
| | - Stephen P Jackson
- Wellcome Trust and Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK; Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1GA, UK.
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29
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Choy KR, Watters DJ. Neurodegeneration in ataxia-telangiectasia: Multiple roles of ATM kinase in cellular homeostasis. Dev Dyn 2017; 247:33-46. [PMID: 28543935 DOI: 10.1002/dvdy.24522] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 05/02/2017] [Accepted: 05/10/2017] [Indexed: 12/13/2022] Open
Abstract
Ataxia-telangiectasia (A-T) is characterized by neuronal degeneration, cancer, diabetes, immune deficiency, and increased sensitivity to ionizing radiation. A-T is attributed to the deficiency of the protein kinase coded by the ATM (ataxia-telangiectasia mutated) gene. ATM is a sensor of DNA double-strand breaks (DSBs) and signals to cell cycle checkpoints and the DNA repair machinery. ATM phosphorylates numerous substrates and activates many cell-signaling pathways. There has been considerable debate about whether a defective DNA damage response is causative of the neurological aspects of the disease. In proliferating cells, ATM is localized mainly in the nucleus; however, in postmitotic cells such as neurons, ATM is mostly cytoplasmic. Recent studies reveal an increasing number of roles for ATM in the cytoplasm, including activation by oxidative stress. ATM associates with organelles including mitochondria and peroxisomes, both sources of reactive oxygen species (ROS), which have been implicated in neurodegenerative diseases and aging. ATM is also associated with synaptic vesicles and has a role in regulating cellular homeostasis and autophagy. The cytoplasmic roles of ATM provide a new perspective on the neurodegenerative process in A-T. This review will examine the expanding roles of ATM in cellular homeostasis and relate these functions to the complex A-T phenotype. Developmental Dynamics 247:33-46, 2018. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Kay Rui Choy
- School of Natural Sciences, Griffith University, Brisbane, Queensland, Australia
| | - Dianne J Watters
- School of Natural Sciences, Griffith University, Brisbane, Queensland, Australia
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Baretić D, Pollard HK, Fisher DI, Johnson CM, Santhanam B, Truman CM, Kouba T, Fersht AR, Phillips C, Williams RL. Structures of closed and open conformations of dimeric human ATM. SCIENCE ADVANCES 2017; 3:e1700933. [PMID: 28508083 PMCID: PMC5425235 DOI: 10.1126/sciadv.1700933] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 04/19/2017] [Indexed: 05/31/2023]
Abstract
ATM (ataxia-telangiectasia mutated) is a phosphatidylinositol 3-kinase-related protein kinase (PIKK) best known for its role in DNA damage response. ATM also functions in oxidative stress response, insulin signaling, and neurogenesis. Our electron cryomicroscopy (cryo-EM) suggests that human ATM is in a dynamic equilibrium between closed and open dimers. In the closed state, the PIKK regulatory domain blocks the peptide substrate-binding site, suggesting that this conformation may represent an inactive or basally active enzyme. The active site is held in this closed conformation by interaction with a long helical hairpin in the TRD3 (tetratricopeptide repeats domain 3) domain of the symmetry-related molecule. The open dimer has two protomers with only a limited contact interface, and it lacks the intermolecular interactions that block the peptide-binding site in the closed dimer. This suggests that the open conformation may be more active. The ATM structure shows the detailed topology of the regulator-interacting N-terminal helical solenoid. The ATM conformational dynamics shown by the structures represent an important step in understanding the enzyme regulation.
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Affiliation(s)
- Domagoj Baretić
- Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Hannah K. Pollard
- Discovery Sciences, Innovative Medicines and Early Development Biotech Unit, AstraZeneca, Darwin Building, Cambridge CB4 0WG, UK
| | - David I. Fisher
- Discovery Sciences, Innovative Medicines and Early Development Biotech Unit, AstraZeneca, Darwin Building, Cambridge CB4 0WG, UK
| | | | - Balaji Santhanam
- Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Caroline M. Truman
- Discovery Sciences, Innovative Medicines and Early Development Biotech Unit, AstraZeneca, Darwin Building, Cambridge CB4 0WG, UK
| | - Tomas Kouba
- Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Alan R. Fersht
- Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Christopher Phillips
- Discovery Sciences, Innovative Medicines and Early Development Biotech Unit, AstraZeneca, Darwin Building, Cambridge CB4 0WG, UK
| | - Roger L. Williams
- Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
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Andersen KR. Insights into Rad3 kinase recruitment from the crystal structure of the DNA damage checkpoint protein Rad26. J Biol Chem 2017; 292:8149-8157. [PMID: 28314775 DOI: 10.1074/jbc.m117.780189] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 03/14/2017] [Indexed: 12/30/2022] Open
Abstract
Metabolic products and environmental factors constantly damage DNA. To protect against these insults and maintain genome integrity, cells have evolved mechanisms to repair DNA lesions. One such mechanism involves Rad3, a master kinase coordinating the DNA damage response. Rad26 is a functional subunit of the Rad3-Rad26 complex and is responsible for bringing the kinase to sites of DNA damage. Here, I present the crystal structure of Rad26 and identify the elements important for recruiting Rad3. The structure suggests that Rad26 is a dimer with a conserved interface in the N-terminal part of the protein. Biochemical data showed that Rad26 uses its C-terminal domain and the flanking kinase-docking motif to bind specific HEAT repeats in Rad3. Analysis of the reconstituted Rad3-Rad26 heterotetrameric complex with electron microscopy enabled me to propose a structural model for its quaternary structure. In conclusion, these results suggest that Rad26 exists as a dimer and provide crucial insight into how Rad3 is recruited and incorporated into the Rad3-Rad26 DNA repair complex.
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Mec1/ATR, the Program Manager of Nucleic Acids Inc. Genes (Basel) 2016; 8:genes8010010. [PMID: 28036033 PMCID: PMC5295005 DOI: 10.3390/genes8010010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2016] [Revised: 12/19/2016] [Accepted: 12/22/2016] [Indexed: 11/17/2022] Open
Abstract
Eukaryotic cells are equipped with surveillance mechanisms called checkpoints to ensure proper execution of cell cycle events. Among these are the checkpoints that detect DNA damage or replication perturbations and coordinate cellular activities to maintain genome stability. At the forefront of damage sensing is an evolutionarily conserved molecule, known respectively in budding yeast and humans as Mec1 (Mitosis entry checkpoint 1) and ATR (Ataxia telangiectasia and Rad3-related protein). Through phosphorylation, Mec1/ATR activates downstream components of a signaling cascade to maintain nucleotide pool balance, protect replication fork integrity, regulate activation of origins of replication, coordinate DNA repair, and implement cell cycle delay. This list of functions continues to expand as studies have revealed that Mec1/ATR modularly interacts with various protein molecules in response to different cellular cues. Among these newly assigned functions is the regulation of RNA metabolism during checkpoint activation and the coordination of replication-transcription conflicts. In this review, I will highlight some of these new functions of Mec1/ATR with a focus on the yeast model organism.
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