Browse
Submit Data
Databases
API
Help

Dataset Information

22 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

The dynamic behavior of Ect2 in response to DNA damage.

ABSTRACT: Ect2 is a BRCT-containing guanidine exchange factor for Rho GTPases. It is essential for cytokinesis and is also involved in tumorigenesis. Since most BRCT-containing proteins are involved in DNA damage response and/or DNA repair, we tested whether Ect2 plays similar roles. We report that in primary mouse embryonic fibroblasts (MEFs), DNA damage quickly led to Ect2 relocalization to the chromatin and DNA damage foci-like structures. Ect2 knockdown did not affect foci localization of γH2AX, TopBP1, or Brca1, or activation of Atm, yet it impeded p53 Ser15 phosphorylation and activation, and resulted in defects in apoptosis and activation of S and G2/M checkpoints in response to DNA damage. These results suggest that Ect2 plays a role in DNA damage response. Interestingly, Ect2 is down-regulated at late stages of DNA damage response. Although p53 and E2F1 have been shown to regulate Ect2 transcription, DNA damage-induced Ect2 down-regulation occurred in p53-/- or Atm-/- MEFs and E2F1 knockdown cells. Instead, DNA damage-induced Ect2 down-regulation is mainly attributable to decreased protein stability. Like Ect2 knockdown, Ect2 destabilization may help the cell to recover from DNA damage response. These results suggest that Ect2 plays roles in multiple aspects of DNA damage response.

SUBMITTER: He D

PROVIDER: S-EPMC4830932 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

DNA-PK promotes activation of the survival kinase AKT in response to DNA damage through an mTORC2-ECT2 pathway.

Project description:The kinase AKT (also known as protein kinase B) is a key regulator of cell proliferation, survival, and metabolism. In addition to being activated by growth factors, AKT is activated in response to DNA damage. Here, we found that the DNA damage response kinase DNA-PK sustains cell survival through a phosphorylation event that leads to increased AKT activity. In various cancer and noncancer cells in culture, DNA damage caused by ionizing radiation or topoisomerase inhibitors triggered DNA-PK–dependent phosphorylation of the mTOR complex 2 (mTORC2) subunit Sin1, which enabled its interaction with the guanine nucleotide exchange factor ECT2. Depleting Sin1 or ECT2 or disrupting the protein interaction or catalytic function of ECT2 attenuated DNA damage–induced AKT activation, thereby enhancing cellular sensitivity to DNA-damaging agents. Our findings elucidate a mechanism mediating DNA damage–induced AKT activation and cell survival.

| S-EPMC8992387 | biostudies-literature

Dynamic behavior of DNA topoisomerase II? in response to DNA double-strand breaks.

Project description:DNA topoisomerase II (Topo II) is crucial for resolving topological problems of DNA and plays important roles in various cellular processes, such as replication, transcription, and chromosome segregation. Although DNA topology problems may also occur during DNA repair, the possible involvement of Topo II in this process remains to be fully investigated. Here, we show the dynamic behavior of human Topo II? in response to DNA double-strand breaks (DSBs), which is the most harmful form of DNA damage. Live cell imaging coupled with site-directed DSB induction by laser microirradiation demonstrated rapid recruitment of EGFP-tagged Topo II? to the DSB site. Detergent extraction followed by immunofluorescence showed the tight association of endogenous Topo II? with DSB sites. Photobleaching analysis revealed that Topo II? is highly mobile in the nucleus. The Topo II catalytic inhibitors ICRF-187 and ICRF-193 reduced the Topo II? mobility and thereby prevented Topo II? recruitment to DSBs. Furthermore, Topo II? knockout cells exhibited increased sensitivity to bleomycin and decreased DSB repair mediated by homologous recombination (HR), implicating the role of Topo II? in HR-mediated DSB repair. Taken together, these results highlight a novel aspect of Topo II? functions in the cellular response to DSBs.

| S-EPMC6037730 | biostudies-literature

Genome-Wide Dynamic Evaluation of the UV-Induced DNA Damage Response.

Project description:Genetic screens in Saccharomyces cerevisiae have allowed for the identification of many genes as sensors or effectors of DNA damage, typically by comparing the fitness of genetic mutants in the presence or absence of DNA-damaging treatments. However, these static screens overlook the dynamic nature of DNA damage response pathways, missing time-dependent or transient effects. Here, we examine gene dependencies in the dynamic response to ultraviolet radiation-induced DNA damage by integrating ultra-high-density arrays of 6144 diploid gene deletion mutants with high-frequency time-lapse imaging. We identify 494 ultraviolet radiation response genes which, in addition to recovering molecular pathways and protein complexes previously annotated to DNA damage repair, include components of the CCR4-NOT complex, tRNA wobble modification, autophagy, and, most unexpectedly, 153 nuclear-encoded mitochondrial genes. Notably, mitochondria-deficient strains present time-dependent insensitivity to ultraviolet radiation, posing impaired mitochondrial function as a protective factor in the ultraviolet radiation response.

| S-EPMC7466999 | biostudies-literature

Dynamic regulation of the COP9 signalosome in response to DNA damage.

Project description:The COP9 signalosome (CSN) is an evolutionarily conserved protein complex that participates in the regulation of the ubiquitin/26S proteasome pathway by controlling the function of cullin-RING-ubiquitin ligases. Impressive progress has been made in deciphering its critical role in diverse cellular and developmental processes. However, little is known about the underlying regulatory principles that coordinate its function. Through biochemical and fluorescence microscopy analyses, we determined that the complex is localized in the cytoplasm, nucleoplasm, and chromatin-bound fractions, each differing in the composition of posttranslationally modified subunits, depending on its location within the cell. During the cell cycle, the segregation between subcellular localizations remains steady. However, upon UV damage, a dose-dependent temporal shuttling of the CSN complex into the nucleus was seen, accompanied by upregulation of specific phosphorylations within CSN1, CSN3, and CSN8. Taken together, our results suggest that the specific spatiotemporal composition of the CSN is highly controlled, enabling the complex to rapidly adapt and respond to DNA damage.

| S-EPMC3958043 | biostudies-literature

The nuclear guanine nucleotide exchange factors Ect2 and Net1 regulate RhoB-mediated cell death after DNA damage.

Project description:Commonly used antitumor treatments, including radiation and chemotherapy, function by damaging the DNA of rapidly proliferating cells. However, resistance to these agents is a predominant clinical problem. A member of the Rho family of small GTPases, RhoB has been shown to be integral in mediating cell death after ionizing radiation (IR) or other DNA damaging agents in Ras-transformed cell lines. In addition, RhoB protein expression increases after genotoxic stress, and loss of RhoB expression causes radio- and chemotherapeutic resistance. However, the signaling pathways that govern RhoB-induced cell death after DNA damage remain enigmatic. Here, we show that RhoB activity increases in human breast and cervical cancer cell lines after treatment with DNA damaging agents. Furthermore, RhoB activity is necessary for DNA damage-induced cell death, as the stable loss of RhoB protein expression using shRNA partially protects cells and prevents the phosphorylation of c-Jun N-terminal kinases (JNKs) and the induction of the pro-apoptotic protein Bim after IR. The increase in RhoB activity after genotoxic stress is associated with increased activity of the nuclear guanine nucleotide exchange factors (GEFs), Ect2 and Net1, but not the cytoplasmic GEFs p115 RhoGEF or Vav2. Importantly, loss of Ect2 and Net1 via siRNA-mediated protein knock-down inhibited IR-induced increases in RhoB activity, reduced apoptotic signaling events, and protected cells from IR-induced cell death. Collectively, these data suggest a mechanism involving the nuclear GEFs Ect2 and Net1 for activating RhoB after genotoxic stress, thereby facilitating cell death after treatment with DNA damaging agents.

| S-EPMC3044157 | biostudies-literature

Influenza infection induces host DNA damage and dynamic DNA damage responses during tissue regeneration.

Project description:Influenza viruses account for significant morbidity worldwide. Inflammatory responses, including excessive generation of reactive oxygen and nitrogen species (RONS), mediate lung injury in severe influenza infections. However, the molecular basis of inflammation-induced lung damage is not fully understood. Here, we studied influenza H1N1 infected cells in vitro, as well as H1N1 infected mice, and we monitored molecular and cellular responses over the course of 2 weeks in vivo. We show that influenza induces DNA damage to both, when cells are directly exposed to virus in vitro (measured using the comet assay) and also when cells are exposed to virus in vivo (estimated via ?H2AX foci). We show that DNA damage, as well as responses to DNA damage persist in vivo until long after virus has been cleared, at times when there are inflammation associated RONS (measured by xanthine oxidase activity and oxidative products). The frequency of lung epithelial and immune cells with increased ?H2AX foci is elevated in vivo, especially for dividing cells (Ki-67-positive) exposed to oxidative stress during tissue regeneration. Additionally, we observed a significant increase in apoptotic cells as well as increased levels of DNA double strand break (DSB) repair proteins Ku70, Ku86 and Rad51 during the regenerative phase. In conclusion, results show that influenza induces DNA damage both in vitro and in vivo, and that DNA damage responses are activated, raising the possibility that DNA repair capacity may be a determining factor for tissue recovery and disease outcome.

| S-EPMC4802977 | biostudies-literature

DNA damage response inhibition at dysfunctional telomeres by modulation of telomeric DNA damage response RNAs.

Project description:The DNA damage response (DDR) is a set of cellular events that follows the generation of DNA damage. Recently, site-specific small non-coding RNAs, also termed DNA damage response RNAs (DDRNAs), have been shown to play a role in DDR signalling and DNA repair. Dysfunctional telomeres activate DDR in ageing, cancer and an increasing number of identified pathological conditions. Here we show that, in mammals, telomere dysfunction induces the transcription of telomeric DDRNAs (tDDRNAs) and their longer precursors from both DNA strands. DDR activation and maintenance at telomeres depend on the biogenesis and functions of tDDRNAs. Their functional inhibition by sequence-specific antisense oligonucleotides allows the unprecedented telomere-specific DDR inactivation in cultured cells and in vivo in mouse tissues. In summary, these results demonstrate that tDDRNAs are induced at dysfunctional telomeres and are necessary for DDR activation and they validate the viability of locus-specific DDR inhibition by targeting DDRNAs.

| S-EPMC5473644 | biostudies-literature

Pharmacological boost of DNA damage response and repair by enhanced biogenesis of DNA damage response RNAs.

Project description:A novel class of small non-coding RNAs called DNA damage response RNAs (DDRNAs) generated at DNA double-strand breaks (DSBs) in a DROSHA- and DICER-dependent manner has been shown to regulate the DNA damage response (DDR). Similar molecules were also reported to guide DNA repair. Here, we show that DDR activation and DNA repair can be pharmacologically boosted by acting on such non-coding RNAs. Cells treated with enoxacin, a compound previously demonstrated to augment DICER activity, show stronger DDR signalling and faster DNA repair upon exposure to ionizing radiations compared to vehicle-only treated cells. Enoxacin stimulates DDRNA production at chromosomal DSBs and at dysfunctional telomeres, which in turn promotes 53BP1 accumulation at damaged sites, therefore in a miRNA-independent manner. Increased 53BP1 occupancy at DNA lesions induced by enoxacin ultimately suppresses homologous recombination, channelling DNA repair towards faster and more accurate non-homologous end-joining, including in post-mitotic primary neurons. Notably, augmented DNA repair stimulated by enoxacin increases the survival also of cancer cells treated with chemotherapeutic agents.

| S-EPMC6478851 | biostudies-literature

Telomeric DNA damage is irreparable and causes persistent DNA-damage-response activation.

Project description:The DNA-damage response (DDR) arrests cell-cycle progression until damage is removed. DNA-damage-induced cellular senescence is associated with persistent DDR. The molecular bases that distinguish transient from persistent DDR are unknown. Here we show that a large fraction of exogenously induced persistent DDR markers is associated with telomeric DNA in cultured cells and mammalian tissues. In yeast, a chromosomal DNA double-strand break next to a telomeric sequence resists repair and impairs DNA ligase 4 recruitment. In mammalian cells, ectopic localization of telomeric factor TRF2 next to a double-strand break induces persistent DNA damage and DDR. Linear, but not circular, telomeric DNA or scrambled DNA induces a prolonged checkpoint in normal cells. In terminally differentiated tissues of old primates, DDR markers accumulate at telomeres that are not critically short. We propose that linear genomes are not uniformly reparable and that telomeric DNA tracts, if damaged, are irreparable and trigger persistent DDR and cellular senescence.

| S-EPMC3717580 | biostudies-literature

The DNA damage response induces IFN.

Project description:This study reveals a new complexity in the cellular response to DNA damage: activation of IFN signaling. The DNA damage response involves the rapid recruitment of repair enzymes and the activation of signal transducers that regulate cell-cycle checkpoints and cell survival. To understand the link between DNA damage and the innate cellular defense that occurs in response to many viral infections, we evaluated the effects of agents such as etoposide that promote dsDNA breaks. Treatment of human cells with etoposide led to the induction of IFN-stimulated genes and the IFN-? and IFN-? genes. NF-?B, known to be activated in response to DNA damage, was shown to be a key regulator of this IFN gene induction. Expression of an NF-?B subunit, p65/RelA, was sufficient for induction of the human IFN-?1 gene. In addition, NF-?B was required for the induction of IFN regulatory factor-1 and -7 that are able to stimulate expression of the IFN-? and IFN-? genes. Cells that lack the NF-?B essential modulator lack the ability to induce the IFN genes following DNA damage. Breaks in DNA are generated during normal physiological processes of replication, transcription, and recombination, as well as by external genotoxic agents or infectious agents. The significant finding of IFN production as a stress response to DNA damage provides a new perspective on the role of IFN signaling.

| S-EPMC3246365 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data