DNA damage sensing by the ATM and ATR kinases.
01 Sep 2013-Cold Spring Harbor Perspectives in Biology (Cold Spring Harb Perspect Biol)-Vol. 5, Iss: 9
TL;DR: The recent findings and current models of how ATM and ATR senseDNA damage, how they are activated by DNA damage, and how they function in concert to regulate the DDR are discussed.
Abstract: In eukaryotic cells, maintenance of genomic stability relies on the coordinated action of a network of cellular processes, including DNA replication, DNA repair, cell-cycle progression, and others. The DNA damage response (DDR) signaling pathway orchestrated by the ATM and ATR kinases is the central regulator of this network in response to DNA damage. Both ATM and ATR are activated by DNA damage and DNA replication stress, but their DNA-damage specificities are distinct and their functions are not redundant. Furthermore, ATM and ATR often work together to signal DNA damage and regulate downstream processes. Here, we will discuss the recent findings and current models of how ATM and ATR sense DNA damage, how they are activated by DNA damage, and how they function in concert to regulate the DDR.
Citations
More filters
TL;DR: In this paper, the kinase ATR (ATM- and Rad3-related) stabilizes and helps to restart stalled replication forks, avoiding the generation of DNA damage and genome instability.
Abstract: Replication stress is a complex phenomenon that has serious implications for genome stability, cell survival and human disease. Generation of aberrant replication fork structures containing single-stranded DNA activates the replication stress response, primarily mediated by the kinase ATR (ATM- and Rad3-related). Along with its downstream effectors, ATR stabilizes and helps to restart stalled replication forks, avoiding the generation of DNA damage and genome instability. Understanding this response may be key to diagnosing and treating human diseases caused by defective responses to replication stress.
1,492 citations
TL;DR: A thorough understanding of DDR pathway complexities must be combined with strategies and lessons learned from the successful registration of PARP inhibitors in order to fully exploit the potential of DDR inhibitors and to ensure their long-term clinical success.
Abstract: J.S. Brown, B. O'Carrigan, and T.A. Yap acknowledge support from the Experimental Cancer Medicine Centre (to The Institute of Cancer Research) and the National Institute for Health Research Biomedical Research Centre (jointly to the Royal Marsden NHS Foundation Trust and The Institute of Cancer Research). Research in The Jackson laboratory is funded by Cancer Research UK (CRUK) program grant number C6/A18796. Core funding is provided by CRUK (C6946/A14492) and the Wellcome Trust (WT092096). S.P. Jackson receives his salary from the University of Cambridge, UK, supplemented by CRUK.
427 citations
Cites background from "DNA damage sensing by the ATM and A..."
...ATR is recruited to RPA– ssDNA by its obligate binding partner ATR-interacting protein (ATRIP) and is activated by topoisomerase binding partner 1 (TOPBP1) in complex with the RAD17-RFC2-5 clamp loader, the 9-1-1 complex (RAD9–RAD1–HUS1), Claspin, and RHINO (57)....
[...]
...ATR is recruited to RPA-ssDNA by its obligate binding partner ATRIP (ATR-interacting protein), and is activated by TOPBP1 (topoisomerase binding partner 1) in complex with the Rad17-Rfc2-5 clamp loader, the 9-1-1 complex (Rad9-Rad1-Hus1), Claspin and RHINO (57)....
[...]
TL;DR: In this article, the molecular mechanisms that underlie cellular senescence and the senescent associated growth arrest with a particular focus on why cells stop dividing, the stability of the growth arrest, the hypersecretory phenotype and how the different pathways are all integrated.
Abstract: Cellular senescence is a stable cell cycle arrest that can be triggered in normal cells in response to various intrinsic and extrinsic stimuli, as well as developmental signals Senescence is considered to be a highly dynamic, multi-step process, during which the properties of senescent cells continuously evolve and diversify in a context dependent manner It is associated with multiple cellular and molecular changes and distinct phenotypic alterations, including a stable proliferation arrest unresponsive to mitogenic stimuli Senescent cells remain viable, have alterations in metabolic activity and undergo dramatic changes in gene expression and develop a complex senescence-associated secretory phenotype Cellular senescence can compromise tissue repair and regeneration, thereby contributing toward aging Removal of senescent cells can attenuate age-related tissue dysfunction and extend health span Senescence can also act as a potent anti-tumor mechanism, by preventing proliferation of potentially cancerous cells It is a cellular program which acts as a double-edged sword, with both beneficial and detrimental effects on the health of the organism, and considered to be an example of evolutionary antagonistic pleiotropy Activation of the p53/p21WAF1/CIP1 and p16INK4A/pRB tumor suppressor pathways play a central role in regulating senescence Several other pathways have recently been implicated in mediating senescence and the senescent phenotype Herein we review the molecular mechanisms that underlie cellular senescence and the senescence associated growth arrest with a particular focus on why cells stop dividing, the stability of the growth arrest, the hypersecretory phenotype and how the different pathways are all integrated
391 citations
TL;DR: The current understanding of the critical functions of the RPA-ssDNA platform in the maintenance of genome stability and its regulation through an elaborate network of covalent modifications is reviewed.
Abstract: The Replication Protein A (RPA) complex is an essential regulator of eukaryotic DNA metabolism. RPA avidly binds to single-stranded DNA (ssDNA) through multiple oligonucleotide/oligosaccharide-binding folds and coordinates the recruitment and exchange of genome maintenance factors to regulate DNA replication, recombination and repair. The RPA-ssDNA platform also constitutes a key physiological signal which activates the master ATR kinase to protect and repair stalled or collapsed replication forks during replication stress. In recent years, the RPA complex has emerged as a key target and an important regulator of post-translational modifications in response to DNA damage, which is critical for its genome guardian functions. Phosphorylation and SUMOylation of the RPA complex, and more recently RPA-regulated ubiquitination, have all been shown to control specific aspects of DNA damage signaling and repair by modulating the interactions between RPA and its partners. Here, we review our current understanding of the critical functions of the RPA-ssDNA platform in the maintenance of genome stability and its regulation through an elaborate network of covalent modifications.
341 citations
TL;DR: The activity of CHK2 in response to DNA damage and in the maintenance of the biological functions in unstressed cells are discussed and their activities are considered in relation to a possible role of CHk2 in tumorigenesis and, as a consequence, in the target of cancer therapy.
Abstract: The serine/threonine kinase CHK2 is a key component of the DNA damage response. In human cells, following genotoxic stress, CHK2 is activated and phosphorylates >20 proteins to induce the appropriate cellular response, which, depending on the extent of damage, the cell type, and other factors, could be cell cycle checkpoint activation, induction of apoptosis or senescence, DNA repair, or tolerance of the damage. Recently, CHK2 has also been found to have cellular functions independent of the presence of nuclear DNA lesions. In particular, CHK2 participates in several molecular processes involved in DNA structure modification and cell cycle progression. In this review, we discuss the activity of CHK2 in response to DNA damage and in the maintenance of the biological functions in unstressed cells. These activities are also considered in relation to a possible role of CHK2 in tumorigenesis and, as a consequence, as a target of cancer therapy.
294 citations
Cites background from "DNA damage sensing by the ATM and A..."
...Whereas ATM seems to be activated primarily by DSBs (Shiloh and Ziv, 2013), ATR is mainly involved in the response to stalled replication forks (Marechal and Zou, 2013), although it can also participate in the DDR to DSBs....
[...]
...Checkpoint mediators (MDC1, 53BP1, and BRCA1 for ATM (Shiloh and Ziv, 2013); and TopBP1 and claspin for ATR) contribute to the activation of ATM and ATR by indirectly binding to the lesions and facilitating recruitment of DDR factors to the damaged sites (Canman, 2003; Marechal and Zou, 2013)....
[...]
References
More filters
TL;DR: This review will focus on how the DDR controls DNA repair and the phenotypic consequences of defects in these critical regulatory functions in mammals.
3,678 citations
TL;DR: It is shown that ATM is held inactive in unirradiated cells as a dimer or higher-order multimer, with the kinase domain bound to a region surrounding serine 1981 that is contained within the previously described ‘FAT’ domain.
Abstract: The ATM protein kinase, mutations of which are associated with the human disease ataxia-telangiectasia, mediates responses to ionizing radiation in mammalian cells. Here we show that ATM is held inactive in unirradiated cells as a dimer or higher-order multimer, with the kinase domain bound to a region surrounding serine 1981 that is contained within the previously described 'FAT' domain. Cellular irradiation induces rapid intermolecular autophosphorylation of serine 1981 that causes dimer dissociation and initiates cellular ATM kinase activity. Most ATM molecules in the cell are rapidly phosphorylated on this site after doses of radiation as low as 0.5 Gy, and binding of a phosphospecific antibody is detectable after the introduction of only a few DNA double-strand breaks in the cell. Activation of the ATM kinase seems to be an initiating event in cellular responses to irradiation, and our data indicate that ATM activation is not dependent on direct binding to DNA strand breaks, but may result from changes in the structure of chromatin.
3,411 citations
TL;DR: The inability to repair DNA damage properly in mammals leads to various disorders and enhanced rates of tumour development, and this work has shown that direct activation of DNA repair networks is needed to correct this problem.
Abstract: The inability to repair DNA damage properly in mammals leads to various disorders and enhanced rates of tumour development. Organisms respond to chromosomal insults by activating a complex damage response pathway. This pathway regulates known responses such as cell-cycle arrest and apoptosis (programmed cell death), and has recently been shown to control additional processes including direct activation of DNA repair networks.
3,230 citations
TL;DR: A large-scale proteomic analysis of proteins phosphorylated in response to DNA damage on consensus sites recognized by ATM and ATR is performed and more than 900 regulated phosphorylation sites encompassing over 700 proteins are identified.
Abstract: Cellular responses to DNA damage are mediated by a number of protein kinases, including ATM (ataxia telangiectasia mutated) and ATR (ATM and Rad3-related). The outlines of the signal transduction portion of this pathway are known, but little is known about the physiological scope of the DNA damage response (DDR). We performed a large-scale proteomic analysis of proteins phosphorylated in response to DNA damage on consensus sites recognized by ATM and ATR and identified more than 900 regulated phosphorylation sites encompassing over 700 proteins. Functional analysis of a subset of this data set indicated that this list is highly enriched for proteins involved in the DDR. This set of proteins is highly interconnected, and we identified a large number of protein modules and networks not previously linked to the DDR. This database paints a much broader landscape for the DDR than was previously appreciated and opens new avenues of investigation into the responses to DNA damage in mammals.
2,967 citations
"DNA damage sensing by the ATM and A..." refers background in this paper
...For example, evidence for a possible cross talk between RNA-processing proteins and the DDR has surfaced from a number of genome-scale studies (Matsuoka et al. 2007; Paulsen et al. 2009; Hurov et al. 2010; Slabicki et al. 2010; Adamson et al. 2012)....
[...]
...Although it tends to be error-prone, NHEJ is a quick and robust way to rejoin DNA ends throughout the cell cycle....
[...]
...In contrast to NHEJ, HR is an error-free repair pathway....
[...]
...ATM has been shown to contribute to NHEJ (Zha et al. 2011)....
[...]
...When DSBs arise in mammalian cells before DNA replication, the first line of defense is usually NHEJ....
[...]
TL;DR: The data suggest that RPA-coated ssDNA is the critical structure at sites of DNA damage that recruits the ATR-ATRIP complex and facilitates its recognition of substrates for phosphorylation and the initiation of checkpoint signaling.
Abstract: The function of the ATR (ataxia-telangiectasia mutated- and Rad3-related)-ATRIP (ATR-interacting protein) protein kinase complex is crucial for the cellular response to replication stress and DNA damage. Here, we show that replication protein A (RPA), a protein complex that associates with single-stranded DNA (ssDNA), is required for the recruitment of ATR to sites of DNA damage and for ATR-mediated Chk1 activation in human cells. In vitro, RPA stimulates the binding of ATRIP to ssDNA. The binding of ATRIP to RPA-coated ssDNA enables the ATR-ATRIP complex to associate with DNA and stimulates phosphorylation of the Rad17 protein that is bound to DNA. Furthermore, Ddc2, the budding yeast homolog of ATRIP, is specifically recruited to double-strand DNA breaks in an RPA-dependent manner. A checkpoint-deficient mutant of RPA, rfa1-t11, is defective for recruiting Ddc2 to ssDNA both in vivo and in vitro. Our data suggest that RPA-coated ssDNA is the critical structure at sites of DNA damage that recruits the ATR-ATRIP complex and facilitates its recognition of substrates for phosphorylation and the initiation of checkpoint signaling.
2,632 citations