Poly(ADP-ribose) polymerase-1 inhibits ATM kinase activity in DNA damage response

Abstract The DNA damage response (DDR) encompasses the cellular response to DNA double-stranded breaks (DSBs), and includes recognition of the DSB, recruitment of numerous factors to the DNA damage site, initiation of signaling cascades, chromatin remodeling, cell-cycle checkpoint activation, and repair of the DSB. Key drivers of the DDR are multiple members of the phosphatidylinositol 3-kinase-related kinase family, including ataxia telangiectasia mutated (ATM), ataxia telangiectasia and Rad3-related (ATR), and the DNA-dependent protein kinase catalytic subunit (DNA-PKcs). ATM and ATR modulate multiple portions of the DDR, but DNA-PKcs is believed to primarily function in the DSB repair pathway, non-homologous end joining. Utilizing a human cell line in which the kinase domain of DNA-PKcs is inactivated, we show here that DNA-PKcs kinase activity is required for the cellular response to DSBs immediately after their induction. Specifically, DNA-PKcs kinase activity initiates phosphorylation of the chromatin factors H2AX and KAP1 following ionizing radiation exposure and drives local chromatin decondensation near the DSB site. Furthermore, loss of DNA-PKcs kinase activity results in a marked decrease in the recruitment of numerous members of the DDR machinery to DSBs. Collectively, these results provide clear evidence that DNA-PKcs activity is pivotal for the initiation of the DDR.

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Phosphorylation of PLK3 Is Controlled by Protein Phosphatase 6

Cells ◽

10.3390/cells9061506 ◽

2020 ◽

Vol 9 (6) ◽

pp. 1506 ◽

Cited By ~ 1

Author(s):

Cecilia Aquino Perez ◽

Matous Palek ◽

Lenka Stolarova ◽

Patrick von Morgen ◽

Libor Macurek

Keyword(s):

Dna Damage ◽

Stress Response ◽

Osmotic Stress ◽

Dna Damage Response ◽

Protein Phosphatase ◽

Gene Editing ◽

Kinase Activity ◽

Cell Cycle Control ◽

Damage Response ◽

Transformed Cell Lines

Polo-like kinases play essential roles in cell cycle control and mitosis. In contrast to other members of this kinase family, PLK3 has been reported to be activated upon cellular stress including DNA damage, hypoxia and osmotic stress. Here we knocked out PLK3 in human non-transformed RPE cells using CRISPR/Cas9-mediated gene editing. Surprisingly, we find that loss of PLK3 does not impair stabilization of HIF1α after hypoxia, phosphorylation of the c-Jun after osmotic stress and dynamics of DNA damage response after exposure to ionizing radiation. Similarly, RNAi-mediated depletion of PLK3 did not impair stress response in human transformed cell lines. Exposure of cells to various forms of stress also did not affect kinase activity of purified EGFP-PLK3. We conclude that PLK3 is largely dispensable for stress response in human cells. Using mass spectrometry, we identify protein phosphatase 6 as a new interacting partner of PLK3. Polo box domain of PLK3 mediates the interaction with the PP6 complex. Finally, we find that PLK3 is phosphorylated at Thr219 in the T-loop and that PP6 constantly dephosphorylates this residue. However, in contrast to PLK1, phosphorylation of Thr219 does not upregulate enzymatic activity of PLK3, suggesting that activation of both kinases is regulated by distinct mechanisms.

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Heterochromatin and the DNA damage response: the need to relaxThis paper is one of a selection of papers in a Special Issue entitled 31st Annual International Asilomar Chromatin and Chromosomes Conference, and has undergone the Journal’s usual peer review process.

Biochemistry and Cell Biology ◽

10.1139/o10-113 ◽

2011 ◽

Vol 89 (1) ◽

pp. 45-60 ◽

Cited By ~ 72

Author(s):

Kendra L. Cann ◽

Graham Dellaire

Keyword(s):

Dna Damage ◽

Dna Damage Response ◽

Chromatin Structure ◽

Peer Review Process ◽

Double Strand Breaks ◽

Dna Double Strand Breaks ◽

Atm Kinase ◽

Strand Breaks ◽

Damage Response ◽

Chromosomal Mutations

Higher order chromatin structure has an impact on all nuclear functions, including the DNA damage response. Over the past several years, it has become increasingly clear that heterochromatin and euchromatin represent separate entities with respect to both damage sensitivity and repair. The chromatin compaction present in heterochromatin helps to protect this DNA from damage; however, when lesions do occur, the compaction restricts the ability of DNA damage response proteins to access the site, as evidenced by its ability to block the expansion of H2AX phosphorylation. As such, DNA damage in heterochromatin is refractory to repair, which requires the surrounding chromatin structure to be decondensed. In the case of DNA double-strand breaks, this relaxation is at least partially mediated by the ATM kinase phosphorylating and inhibiting the function of the transcriptional repressor KAP1. This review will focus on the functions of KAP1 and other proteins involved in the maintenance or restriction of heterochromatin, including HP1 and TIP60, in the DNA damage response. As heterochromatin is important for maintaining genomic stability, cells must maintain a delicate balance between allowing repair factors access to these regions and ensuring that these regions retain their organization to prevent increased DNA damage and chromosomal mutations.

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MYST Family Lysine Acetyltransferase Facilitates Ataxia Telangiectasia Mutated (ATM) Kinase-mediated DNA Damage Response inToxoplasma gondii

Journal of Biological Chemistry ◽

10.1074/jbc.m109.066134 ◽

2010 ◽

Vol 285 (15) ◽

pp. 11154-11161 ◽

Cited By ~ 25

Author(s):

Nathalie Vonlaufen ◽

Arunasalam Naguleswaran ◽

Isabelle Coppens ◽

William J. Sullivan

Keyword(s):

Dna Damage ◽

Dna Damage Response ◽

Ataxia Telangiectasia ◽

Ataxia Telangiectasia Mutated ◽

Atm Kinase ◽

Damage Response ◽

Lysine Acetyltransferase

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Inhibition of the ATM/p53 Signal Transduction Pathway by Kaposi's Sarcoma-Associated Herpesvirus Interferon Regulatory Factor 1

Journal of Virology ◽

10.1128/jvi.80.5.2257-2266.2006 ◽

2006 ◽

Vol 80 (5) ◽

pp. 2257-2266 ◽

Cited By ~ 93

Author(s):

Young C. Shin ◽

Hiroyuki Nakamura ◽

Xiaozhen Liang ◽

Pinghui Feng ◽

Heesoon Chang ◽

...

Keyword(s):

Dna Damage ◽

Dna Damage Response ◽

Signal Transduction Pathway ◽

Interferon Regulatory Factor ◽

Transduction Pathway ◽

Regulatory Factor ◽

Atm Kinase ◽

Interferon Regulatory Factor 1 ◽

Damage Response ◽

Infected Cells

ABSTRACT Infected cells recognize viral replication as a DNA damage stress and elicit the ataxia telangiectasia-mutated (ATM)/p53-mediated DNA damage response signal transduction pathway as part of the host surveillance mechanisms, which ultimately induces the irreversible cell cycle arrest and apoptosis. Viruses have evolved a variety of mechanisms to counteract this host intracellular innate immunity. Kaposi's sarcoma-associated herpesvirus (KSHV) viral interferon regulatory factor 1 (vIRF1) interacts with the cellular p53 tumor suppressor through its central DNA binding domain, and this interaction inhibits transcriptional activation of p53. Here, we further demonstrate that KSHV vIRF1 downregulates the total p53 protein level by facilitating its proteasome-mediated degradation. Detailed biochemical study showed that vIRF1 interacted with cellular ATM kinase through its carboxyl-terminal transactivation domain and that this interaction blocked the activation of ATM kinase activity induced by DNA damage stress. As a consequence, vIRF1 expression greatly reduced the level of serine 15 phosphorylation of p53, resulting in an increase of p53 ubiquitination and thereby a decrease of its protein stability. These results indicate that KSHV vIRF1 comprehensively compromises an ATM/p53-mediated DNA damage response checkpoint by targeting both upstream ATM kinase and downstream p53 tumor suppressor, which might circumvent host growth surveillance and facilitate viral replication in infected cells.

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