scholarly journals Dephosphorylation of the C-terminal Tyrosyl Residue of the DNA Damage-related Histone H2A.X Is Mediated by the Protein Phosphatase Eyes Absent

2009 ◽  
Vol 284 (24) ◽  
pp. 16066-16070 ◽  
Author(s):  
Navasona Krishnan ◽  
Dae Gwin Jeong ◽  
Suk-Kyeong Jung ◽  
Seong Eon Ryu ◽  
Andrew Xiao ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Damage Response ◽  
Mammalian Cells ◽  
Protein Tyrosine Phosphatases ◽  
Histone H2a ◽  
Eyes Absent ◽  
Damage Repair ◽  
Damage Response

In mammalian cells, the DNA damage-related histone H2A variant H2A.X is characterized by a C-terminal tyrosyl residue, Tyr-142, which is phosphorylated by an atypical kinase, WSTF. The phosphorylation status of Tyr-142 in H2A.X has been shown to be an important regulator of the DNA damage response by controlling the formation of γH2A.X foci, which are platforms for recruiting molecules involved in DNA damage repair and signaling. In this work, we present evidence to support the identification of the Eyes Absent (EYA) phosphatases, protein-tyrosine phosphatases of the haloacid dehalogenase superfamily, as being responsible for dephosphorylating the C-terminal tyrosyl residue of histone H2A.X. We demonstrate that EYA2 and EYA3 displayed specificity for Tyr-142 of H2A.X in assays in vitro. Suppression of eya3 by RNA interference resulted in elevated basal phosphorylation and inhibited DNA damage-induced dephosphorylation of Tyr-142 of H2A.X in vivo. This study provides the first indication of a physiological substrate for the EYA phosphatases and suggests a novel role for these enzymes in regulation of the DNA damage response.

scholarly journals PAICS contributes to gastric carcinogenesis and participates in DNA damage response by interacting with histone deacetylase 1/2

2020 ◽  
Vol 11 (7) ◽  
Author(s):  
Nan Huang ◽  
Chang Xu ◽  
Liang Deng ◽  
Xue Li ◽  
Zhixuan Bian ◽  
...  
Keyword(s):  
Dna Damage ◽  
Histone Deacetylase ◽  
Dna Damage Response ◽  
De Novo ◽  
Dna Damage Repair ◽  
Histone Deacetylase 1 ◽  
Damage Repair ◽  
Damage Response

AbstractPhosphoribosylaminoimidazole carboxylase, phosphoribosylaminoimidazole succinocarboxamide synthetase (PAICS), an essential enzyme involved in de novo purine biosynthesis, is connected with formation of various tumors. However, the specific biological roles and related mechanisms of PAICS in gastric cancer (GC) remain unclear. In the present study, we identified for the first time that PAICS was significantly upregulated in GC and high expression of PAICS was correlated with poor prognosis of patients with GC. In addition, knockdown of PAICS significantly induced cell apoptosis, and inhibited GC cell growth both in vitro and in vivo. Mechanistic studies first found that PAICS was engaged in DNA damage response, and knockdown of PAICS in GC cell lines induced DNA damage and impaired DNA damage repair efficiency. Further explorations revealed that PAICS interacted with histone deacetylase HDAC1 and HDAC2, and PAICS deficiency decreased the expression of DAD51 and inhibited its recruitment to DNA damage sites by impairing HDAC1/2 deacetylase activity, eventually preventing DNA damage repair. Consistently, PAICS deficiency enhanced the sensitivity of GC cells to DNA damage agent, cisplatin (CDDP), both in vitro and in vivo. Altogether, our findings demonstrate that PAICS plays an oncogenic role in GC, which act as a novel diagnosis and prognostic biomarker for patients with GC.

scholarly journals OR16-06 Age-Associated Local GH Promotes Colon Neoplasia

2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Vera M Chesnokova ◽  
Svetlana Zonis ◽  
Nasia Apostolou ◽  
Estrada Q Hannah ◽  
Simon Knott ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Damage Response ◽  
Human Colon ◽  
Colon Cells ◽  
Intestinal Organoids ◽  
Age Related ◽  
Damage Repair ◽  
Damage Response

Abstract Colon polyp and cancer frequency increase with age, yet little is known about age-related mechanisms underlying development of these neoplasms. Defective DNA damage response and accumulation of unrepaired DNA damage can trigger genomic instability and cellular transformation. Patients with acromegaly have a higher prevalence of colon polyps and, arguably, colon adenocarcinoma, while those with GH signaling deficiency do not develop cancer. We showed that APC+/- mice that all develop colon adenomas exhibit a significant decrease in the number and volume of colon tumors with deletion of the GH transcription factor Prop1. Further, DNA damage response triggered GH expression in colon cells, and GH, in turn, altered DNA damage repair, resulting in DNA damage accumulation and cell transformation both in vitro and in vivo. These findings prompted us to hypothesize that accumulated DNA damage in aging colon induces local GH, suppressing DNA damage repair and creating a milieu consistent with genomic instability favoring neoplastic development. In human colon tissue we now show increased expression of γH2AX, a marker of DNA breaks, associated with increased GH transcription (detected by RNA scope) and translation (assessed by immunohistochemistry) as well as GH induction in both human and murine colon after DNA damaging radiotherapy. In vitro studies support these results, showing GH induction in normal human colon epithelial cells, fibroblasts, and 3D human intestinal organoids after DNA damage. Of note, local GH was secreted in the medium, indicating a paracrine effect. Paracrine/autocrine GH expression in these cellular models resulted in suppression of p53, induction of EMT, and attenuation of DNA damage response, and accumulated unrepaired DNA damage in human colon cells and in human intestinal organoids. In vivo, colon cells infected with lentivirus expressing GH generated more metastases than did cells expressing control vector. Co-culturing of human normal colon fibroblasts expressing GH together with normal human colon cells led to increased motility and accumulation of DNA damage as well as increased proliferation of epithelial cells on a gut-on-a-chip microfluidic device, confirming paracrine GH effects. In an in vitro model of aging, culturing human intestinal organoids for up to 2 months resulted in decreased telomere length and increased GH mRNA and protein expression associated with suppressed DNA damage response evident by decreased phosphorylation of ATM and DNA-PKcs, both kinases involved in DNA repair, and DNA damage accumulation assessed by Comet assay. Suppression of GH in these aging organoids led to increased phospho-p53 and reduced DNA damage. Although somatotroph axis endocrine activity decreases with age, local GH induced in response to age-related DNA damage may trigger a “field change,” creating a milieu favorable for colon neoplastic development.

scholarly journals Tight regulation of ubiquitin-mediated DNA damage response by USP3 preserves the functional integrity of hematopoietic stem cells

2014 ◽  
Vol 211 (9) ◽  
pp. 1759-1777 ◽  
Author(s):  
Cesare Lancini ◽  
Paul C.M. van den Berk ◽  
Joseph H.A. Vissers ◽  
Gaetano Gargiulo ◽  
Ji-Ying Song ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Damage Response ◽  
Genotoxic Stress ◽  
Histone H2a ◽  
Deubiquitinating Enzymes ◽  
Dna Breaks ◽  
Hematopoietic Stem ◽  
Damage Response

Histone ubiquitination at DNA breaks is required for activation of the DNA damage response (DDR) and DNA repair. How the dynamic removal of this modification by deubiquitinating enzymes (DUBs) impacts genome maintenance in vivo is largely unknown. To address this question, we generated mice deficient for Ub-specific protease 3 (USP3; Usp3Δ/Δ), a histone H2A DUB which negatively regulates ubiquitin-dependent DDR signaling. Notably, USP3 deletion increased the levels of histone ubiquitination in adult tissues, reduced the hematopoietic stem cell (HSC) reserves over time, and shortened animal life span. Mechanistically, our data show that USP3 is important in HSC homeostasis, preserving HSC self-renewal, and repopulation potential in vivo and proliferation in vitro. A defective DDR and unresolved spontaneous DNA damage contribute to cell cycle restriction of Usp3Δ/Δ HSCs. Beyond the hematopoietic system, Usp3Δ/Δ animals spontaneously developed tumors, and primary Usp3Δ/Δ cells failed to preserve chromosomal integrity. These findings broadly support the regulation of chromatin ubiquitination as a key pathway in preserving tissue function through modulation of the response to genotoxic stress.

scholarly journals The DNA damage inducible lncRNA SCAT7 regulates genomic integrity and topoisomerase 1 turnover in lung adenocarcinoma

NAR Cancer ◽  
2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Luisa Statello ◽  
Mohamad M Ali ◽  
Silke Reischl ◽  
Sagar Mahale ◽  
Subazini Thankaswamy Kosalai ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Damage Response ◽  
Cancer Biology ◽  
Topoisomerase I ◽  
Cell Cycle Checkpoints ◽  
Topoisomerase 1 ◽  
Damage Response ◽  
Promote Cell Survival

Abstract Despite the rapid improvements in unveiling the importance of lncRNAs in all aspects of cancer biology, there is still a void in mechanistic understanding of their role in the DNA damage response. Here we explored the potential role of the oncogenic lncRNA SCAT7 (ELF3-AS1) in the maintenance of genome integrity. We show that SCAT7 is upregulated in response to DNA-damaging drugs like cisplatin and camptothecin, where SCAT7 expression is required to promote cell survival. SCAT7 silencing leads to decreased proliferation of cisplatin-resistant cells in vitro and in vivo through interfering with cell cycle checkpoints and DNA repair molecular pathways. SCAT7 regulates ATR signaling, promoting homologous recombination. Importantly, SCAT7 also takes part in proteasome-mediated topoisomerase I (TOP1) degradation, and its depletion causes an accumulation of TOP1–cc structures responsible for the high levels of intrinsic DNA damage. Thus, our data demonstrate that SCAT7 is an important constituent of the DNA damage response pathway and serves as a potential therapeutic target for hard-to-treat drug resistant cancers.

scholarly journals SIRT7-mediated ATM deacetylation is essential for its deactivation and DNA damage repair

2019 ◽  
Vol 5 (3) ◽  
pp. eaav1118 ◽  
Author(s):  
Ming Tang ◽  
Zhiming Li ◽  
Chaohua Zhang ◽  
Xiaopeng Lu ◽  
Bo Tu ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Damage Repair ◽  
Class Iii ◽  
Ataxia Telangiectasia Mutated ◽  
Damage Repair ◽  
Damage Response ◽  
Late Stages

The activation of ataxia-telangiectasia mutated (ATM) upon DNA damage involves a cascade of reactions, including acetylation by TIP60 and autophosphorylation. However, how ATM is progressively deactivated after completing DNA damage repair remains obscure. Here, we report that sirtuin 7 (SIRT7)–mediated deacetylation is essential for dephosphorylation and deactivation of ATM. We show that SIRT7, a class III histone deacetylase, interacts with and deacetylates ATM in vitro and in vivo. In response to DNA damage, SIRT7 is mobilized onto chromatin and deacetylates ATM during the late stages of DNA damage response, when ATM is being gradually deactivated. Deacetylation of ATM by SIRT7 is prerequisite for its dephosphorylation by its phosphatase WIP1. Consequently, depletion of SIRT7 or acetylation-mimic mutation of ATM induces persistent ATM phosphorylation and activation, thus leading to impaired DNA damage repair. Together, our findings reveal a previously unidentified role of SIRT7 in regulating ATM activity and DNA damage repair.

scholarly journals Nuclear Accumulation of LAP1:TRF2 Complex during DNA Damage Response Uncovers a Novel Role for LAP1

Cells ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1804
Author(s):  
Cátia D. Pereira ◽  
Filipa Martins ◽  
Mariana Santos ◽  
Thorsten Müeller ◽  
Odete A. B. da Cruz e Silva ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Damage Response ◽  
Cellular Response ◽  
Nuclear Accumulation ◽  
Protein Levels ◽  
Dna Damaging Agents ◽  
Physiological Properties ◽  
Damage Response

Lamina-associated polypeptide 1 (LAP1) is a nuclear envelope (NE) protein whose function remains poorly characterized. In a recent LAP1 protein interactome study, a putative regulatory role in the DNA damage response (DDR) has emerged and telomeric repeat-binding factor 2 (TRF2), a protein intimately associated with this signaling pathway, was among the list of LAP1 interactors. To gain insights into LAP1′s physiological properties, the interaction with TRF2 in human cells exposed to DNA-damaging agents was investigated. The direct LAP1:TRF2 binding was validated in vitro by blot overlay and in vivo by co-immunoprecipitation after hydrogen peroxide and bleomycin treatments. The regulation of this protein interaction by LAP1 phosphorylation was demonstrated by co-immunoprecipitation and mass spectrometry following okadaic acid exposure. The involvement of LAP1 and TRF2 in the DDR was confirmed by their increased nuclear protein levels after bleomycin treatment, evaluated by immunoblotting, as well as by their co-localization with DDR factors at the NE and within the nucleoplasm, assessed by immunocytochemistry. Effectively, we showed that the LAP1:TRF2 complex is established during a cellular response against DNA damage. This work proposes a novel functional role for LAP1 in the DDR, revealing a potential biological mechanism that may be disrupted in LAP1-associated pathologies.

scholarly journals Attenuating the DNA damage response to double-strand breaks restores function in models of CNS neurodegeneration

2019 ◽  
Vol 1 (1) ◽  
Author(s):  
Richard I Tuxworth ◽  
Matthew J Taylor ◽  
Ane Martin Anduaga ◽  
Alaa Hussien-Ali ◽  
Sotiroula Chatzimatthaiou ◽  
...  
Keyword(s):  
Dna Damage ◽  
Nervous System ◽  
Dna Damage Response ◽  
Neurological Disorders ◽  
Double Strand Breaks ◽  
Strand Breaks ◽  
Damage Response ◽  
Ganglion Neurons

Abstract DNA double-strand breaks are a feature of many acute and long-term neurological disorders, including neurodegeneration, following neurotrauma and after stroke. Persistent activation of the DNA damage response in response to double-strand breaks contributes to neural dysfunction and pathology as it can force post-mitotic neurons to re-enter the cell cycle leading to senescence or apoptosis. Mature, non-dividing neurons may tolerate low levels of DNA damage, in which case muting the DNA damage response might be neuroprotective. Here, we show that attenuating the DNA damage response by targeting the meiotic recombination 11, Rad50, Nijmegen breakage syndrome 1 complex, which is involved in double-strand break recognition, is neuroprotective in three neurodegeneration models in Drosophila and prevents Aβ1-42-induced loss of synapses in embryonic hippocampal neurons. Attenuating the DNA damage response after optic nerve injury is also neuroprotective to retinal ganglion cells and promotes dramatic regeneration of their neurites both in vitro and in vivo. Dorsal root ganglion neurons similarly regenerate when the DNA damage response is targeted in vitro and in vivo and this strategy also induces significant restoration of lost function after spinal cord injury. We conclude that muting the DNA damage response in the nervous system is neuroprotective in multiple neurological disorders. Our results point to new therapies to maintain or repair the nervous system.

scholarly journals ATR-dependent phosphorylation of FANCA on serine 1449 after DNA damage is important for FA pathway function

Blood ◽  
2009 ◽  
Vol 113 (10) ◽  
pp. 2181-2190 ◽  
Author(s):  
Natalie B. Collins ◽  
James B. Wilson ◽  
Thomas Bush ◽  
Andrei Thomashevski ◽  
Kate J. Roberts ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Dna Damage ◽  
Dna Damage Response ◽  
Fanconi Anemia ◽  
Posttranslational Modifications ◽  
S Phase ◽  
Damage Response ◽  
Pathway Function

Abstract Previous work has shown several proteins defective in Fanconi anemia (FA) are phosphorylated in a functionally critical manner. FANCA is phosphorylated after DNA damage and localized to chromatin, but the site and significance of this phosphorylation are unknown. Mass spectrometry of FANCA revealed one phosphopeptide, phosphorylated on serine 1449. Serine 1449 phosphorylation was induced after DNA damage but not during S phase, in contrast to other posttranslational modifications of FA proteins. Furthermore, the S1449A mutant failed to completely correct a variety of FA-associated phenotypes. The DNA damage response is coordinated by phosphorylation events initiated by apical kinases ATM (ataxia telangectasia mutated) and ATR (ATM and Rad3-related), and ATR is essential for proper FA pathway function. Serine 1449 is in a consensus ATM/ATR site, phosphorylation in vivo is dependent on ATR, and ATR phosphorylated FANCA on serine 1449 in vitro. Phosphorylation of FANCA on serine 1449 is a DNA damage–specific event that is downstream of ATR and is functionally important in the FA pathway.

scholarly journals Crosstalk between H2A variant-specific modifications impacts vital cell functions

PLoS Genetics ◽  
2021 ◽  
Vol 17 (6) ◽  
pp. e1009601
Author(s):  
Anna Schmücker ◽  
Bingkun Lei ◽  
Zdravko J. Lorković ◽  
Matías Capella ◽  
Sigurd Braun ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Damage Response ◽  
Mutual Exclusion ◽  
Histone H2a ◽  
Cell Functions ◽  
Vital Cell ◽  
Damage Response ◽  
Cycle Dependent ◽  
Selection Of

Selection of C-terminal motifs participated in evolution of distinct histone H2A variants. Hybrid types of variants combining motifs from distinct H2A classes are extremely rare. This suggests that the proximity between the motif cases interferes with their function. We studied this question in flowering plants that evolved sporadically a hybrid H2A variant combining the SQ motif of H2A.X that participates in the DNA damage response with the KSPK motif of H2A.W that stabilizes heterochromatin. Our inventory of PTMs of H2A.W variants showed that in vivo the cell cycle-dependent kinase CDKA phosphorylates the KSPK motif of H2A.W but only in absence of an SQ motif. Phosphomimicry of KSPK prevented DNA damage response by the SQ motif of the hybrid H2A.W/X variant. In a synthetic yeast expressing the hybrid H2A.W/X variant, phosphorylation of KSPK prevented binding of the BRCT-domain protein Mdb1 to phosphorylated SQ and impaired response to DNA damage. Our findings illustrate that PTMs mediate interference between the function of H2A variant specific C-terminal motifs. Such interference could explain the mutual exclusion of motifs that led to evolution of H2A variants.

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