Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Noncanonical mRNA decay by the endoplasmic-reticulum stress sensor IRE1-alpha promotes cancer cell survival [GRO-seq]

ABSTRACT: Eukaryotic IRE1 mitigates endoplasmic-reticulum (ER) stress by orchestrating the unfolded-protein response (UPR). IRE1 spans the ER membrane, and signals through a cytosolic kinase-endoribonuclease module. The endoribonuclease generates the transcription factor XBP1s by intron excision between similar RNA stem-loop endomotifs, and depletes select cellular mRNAs through regulated IRE1-dependent decay (RIDD). Paradoxically, mammalian RIDD seemingly targets only mRNAs with XBP1-like endomotifs, while in flies RIDD exhibits little sequence restriction. By comparing nascent and total IRE1α-controlled mRNAs in human breast cancer cells, we discovered not only canonical endomotif-containing RIDD substrates, but also many targets lacking recognizable motifs—degraded by a process we coin RIDDLE, for RIDD lacking endomotif. IRE1α displayed two basic endoribonuclease modalities: endomotif-specific cleavage, minimally requiring dimers; and endomotif-independent promiscuous processing, requiring phospho-oligomers. An oligomer-deficient mutant that did not support RIDDLE failed to rescue cancer-cell viability. These results link IRE1α oligomers, RIDDLE, and cell survival, advancing mechanistic understanding of the UPR.

ORGANISM(S): Homo sapiens

PROVIDER: GSE169583 | GEO | 2021/06/01

REPOSITORIES: GEO

ACCESS DATA

Json Xml

Similar Datasets

Noncanonical mRNA decay by the endoplasmic-reticulum stress sensor IRE1-alpha promotes cancer cell survival [RNA-seq]

Project description:Eukaryotic IRE1 mitigates endoplasmic-reticulum (ER) stress by orchestrating the unfolded-protein response (UPR). IRE1 spans the ER membrane, and signals through a cytosolic kinase-endoribonuclease module. The endoribonuclease generates the transcription factor XBP1s by intron excision between similar RNA stem-loop endomotifs, and depletes select cellular mRNAs through regulated IRE1-dependent decay (RIDD). Paradoxically, mammalian RIDD seemingly targets only mRNAs with XBP1-like endomotifs, while in flies RIDD exhibits little sequence restriction. By comparing nascent and total IRE1α-controlled mRNAs in human breast cancer cells, we discovered not only canonical endomotif-containing RIDD substrates, but also many targets lacking recognizable motifs—degraded by a process we coin RIDDLE, for RIDD lacking endomotif. IRE1α displayed two basic endoribonuclease modalities: endomotif-specific cleavage, minimally requiring dimers; and endomotif-independent promiscuous processing, requiring phospho-oligomers. An oligomer-deficient mutant that did not support RIDDLE failed to rescue cancer-cell viability. These results link IRE1α oligomers, RIDDLE, and cell survival, advancing mechanistic understanding of the UPR.

2021-06-01 | GSE169584 | GEO

Regulated Ire1-dependent mRNA decay requires no-go mRNA degradation to maintain endoplasmic reticulum homeostasis in S. pombe

Project description:The unfolded protein response (UPR) continually monitors the protein folding capacity of the endoplasmic reticulum (ER). In S. pombe, Ire1, an ER membrane-resident kinase/endoribonuclease, utilizes a mechanism of selective degradation of ER-targeted mRNAs (RIDD) to maintain ER homeostasis. Here, we used a genetic screen to identify factors critical to the Ire1-mediated UPR response in S. pombe and found several proteins, Dom34, Hbs1 and SkiX, previously implicated in ribosome rescue and the no-go-decay (NGD) pathway. Ribosome profiling in ER-stressed cells lacking these factors revealed that Ire1-mediated cleavage on ER-associated mRNAs results in ribosome stalling on the cleaved transcript and, ultimately in full mRNA degradation. The process engages mechanisms of precise, iterated cleavage of the mRNAs and ribosome rescue. This clear signature allowed us to discover hundreds of novel mRNA targets of Ire1. Our results reveal that the UPR in S. pombe executes RIDD in an intricate interplay between Ire1, translation, and the NGD surveillance pathway, and establish a critical role for NGD in maintaining ER homeostasis.

2017-09-14 | GSE98934 | GEO

Stress-induced tyrosine phosphorylation of RtcB modulates IRE1 activity and signaling outputs.

Project description:Endoplasmic Reticulum (ER) stress is a hallmark of various diseases, which is dealt with through the activation of an adaptive signaling pathway named the Unfolded Protein Response (UPR). This response is mediated by three ER-resident sensors and the most evolutionary conserved, IRE1α signals through its cytosolic kinase and endoribonuclease (RNase) activities. IRE1α RNase activity can either catalyze the initial step of XBP1 mRNA unconventional splicing or degrade a number of RNAs through Regulated IRE1-Dependent Decay (RIDD). The balance between these two activities plays an instrumental role in cells’ life and death decisions upon ER stress. Until now, the biochemical and biological outputs of IRE1α RNase activity have been well documented, however, the precise mechanisms controlling whether IRE1 signaling is adaptive or pro-death (terminal) remain unclear. This prompted us to further investigate those mechanisms and we hypothesized that XBP1 mRNA splicing and RIDD activity could be co-regulated by the IRE1α RNase regulatory network. We showed that a key nexus in this pathway is the tRNA ligase RtcB which, together with IRE1α, is responsible for XBP1 mRNA splicing. We demonstrated that RtcB is tyrosine phosphorylated by c-Abl and dephosphorylated by PTP1B. Moreover, we identified RtcB Y306 as a key residue which, when phosphorylated, perturbs RtcB interaction with IRE1α, thereby attenuating XBP1 mRNA splicing and favoring RIDD. Our results demonstrate that the IRE1α RNase regulatory network is dynamically fine-tuned by tyrosine kinases and phosphatases upon various stresses and that the nature of the stress determines cell adaptive or death outputs.

2022-02-21 | PXD023433 | Pride

Expression data from IRE1a or XBP1 deficient mouse liver

Project description:IRE1a and XBP1 are key regulators of the unfolded protein response (UPR). XBP1 ablation causes profound hypolipidemia in mice, and triggers feedback activation of its upstream enzyme IRE1a, instigating regulated IRE1-dependent decay (RIDD), an mRNA degradation mechanism dependent on IRE1a's endoribonuclease activity. Comprehensive microarray analysis of XBP1 and/or IRE1a deficient liver identified genes involved in lipogenesis and lipoprotein metabolism as RIDD substrates, which might contribute to the suppression of plasma lipid levels by activated IRE1a. To identify RIDD substrate mRNAs and direct XBP1 targets in the liver, we performed a comprehensive comparative microarray analysis of three groups of RNA samples: WT and XBP1 deficient mice, WT and IRE1a deficient mice untreated or injected with tunicamycin, and XBP1 deficient mice injected with luciferase or IRE1a siRNA.

2012-10-17 | E-GEOD-40515 | biostudies-arrayexpress

RNA sequencing identifies novel regulated IRE1-dependent decay targets that affect multiple myeloma survival and proliferation

Project description:IRE1 is an unfolded protein response (UPR) sensor with kinase and endonuclease activity. It plays a central role in the endoplasmic reticulum (ER) stress response through unconventional splicing of XBP1 mRNA and regulated IRE1-dependent decay (RIDD), which cleaves RNA at an XBP1-like consensus sequence (CUGCAG) accompanied by a stem-loop structure. MM cells are known to exhibit an elevated level of baseline ER stress, but RIDD activity has not been well studied in this disease. To investigate novel RIDD targets of possible relevance to the survival/proliferation of MM cells we combined in vitro cleavage assay with RNA sequencing. Bioinformatic analysis revealed hundreds of putative IRE1 substrates, 32 of which were chosen for validation. Looking into the secondary structure of IRE1 substrates, we found that the consensus sequences of IRF4, PRDM1, IKZF1, KLF13, NOTCH1, ATR, DICER, RICTOR, CDK12, FAM168B, and CENPF mRNAs were accompanied by a stem-loop structure essential for IRE1-mediated cleavage. We show that mRNA and protein levels corresponding to these targets were attenuated in an IRE1-dependent manner by treatment with ER-stress-inducing agents. Our results demonstrate for the first time that IRE1 is a key regulator of several proteins of importance in MM survival and proliferation.

2022-04-06 | GSE152070 | GEO

Expression data from IRE1a or XBP1 deficient mouse liver

2012-10-17 | GSE40515 | GEO

Intercepting IRE1 Kinase-FMRP Signaling Prevents Atherosclerosis Progression

Project description:Fragile X Mental Retardation protein (FMRP), widely known for its role in hereditary intellectual disability, is an RNA-binding protein (RBP) that controls translation of select mRNAs. We discovered that endoplasmic reticulum (ER) stress induces phosphorylation of FMRP on a site that is known to enhance translation inhibition of FMRP-bound mRNAs. We show ER stress-induced activation of Inositol requiring enzyme-1 (IRE1), an ER-resident stress-sensing kinase/endoribonuclease, leads to FMRP phosphorylation and to suppression of macrophage cholesterol efflux and apoptotic cell clearance (efferocytosis). Conversely, FMRP-deficiency and pharmacological inhibition of IRE1 kinase activity enhances cholesterol efflux and efferocytosis, reducing atherosclerosis in mice. Our results provide mechanistic insights into how ER stress-induced IRE1 kinase activity contributes to macrophage cholesterol homeostasis and suggest IRE1 inhibition as a promising new way to counteract atherosclerosis.

2022-02-15 | PXD030594 | Pride

A role for the ribosome-associated complex in activation of the IRE1 branch of UPR

Project description:The ubiquitous ribosome-associated complex (RAC) is a chaperone that spans ribosomes, making contacts near both the polypeptide exit tunnel and the decoding center, a position prime for sensing and coordinating translation and folding. Loss of RAC is known to result in growth defects and sensitization to translational and osmotic stresses. However, the physiological substrates of RAC and the mechanism(s) by which RAC is involved in responding to specific stresses in higher eukaryotes remain obscure. Data presented here uncover an essential function of mammalian RAC in the unfolded protein response (UPR). Knockdown of RAC sensitizes mammalian cells to ER stress and selectively interferes with IRE1 branch activation. Higher-order oligomerization of the IRE1α kinase/endoribonuclease depends upon RAC. These results reveal a surveillance function for RAC in the UPR: modulating IRE1α clustering as required for endonuclease activation and splicing of the substrate Xbp1 mRNA.

2021-06-14 | GSE173852 | GEO

The IRE1 interactome in human LS174T colon epithelial cells

Project description:Inositol-Requiring Enzyme (IRE)1 is an evolutionarily conserved sensor protein of the unfolded protein response (UPR). Vertebrates express two distinct paralogues: IRE1α (gene name ERN1) and IRE1β (gene name ERN2). Both proteins have a similar overall structure, with a sensor domain positioned in the endoplasmic reticulum (ER) lumen, and cytoplasmic kinase and endonuclease domains. For IRE1α, it is well-established that a protein folding chaperone called HSPA5 binds to the ER-luminal domain in conditions when the folding load and capacity are balanced. When unfolded proteins accumulate, HSPA5 is recruited to these unfolded proteins to aid in folding, thereby releasing IRE1α. This initiates a chain reaction of dimerization, trans-autophosphorylation and further oligomerization, resulting in an endonuclease-active IRE1α. Activated IRE1α cleaves an intron from the X-box binding protein 1 mRNA in an unusual cytoplasmic splicing reaction, and the resulting frameshift leads to production of a central UPR transcription factor, XBP1S. In contrast to this, IRE1β is far less extensively characterized. It is expressed solely in mucus-producing cells, more specifically goblet cells. Ectopic expression in other cell types such as Hela cells causes rapid cell death, most likely due to unregulated endonuclease activity. Upon aligning the two IRE1 paralogues, it becomes clear that the luminal domain has the lowest homology between the two paralogues, suggesting differences in how activity of either paralogue is tuned in the ER. In this project, we aimed to characterize and compare the IRE1β and IRE1α interactomes in LS174T cells, a cell line that has retained many goblet cell characteristics, to gain more insights into the regulation and downstream activity of IRE1β in a more relevant cellular background.

2023-11-21 | PXD042756 | Pride

Regulated IRE1α-dependent decay (RIDD)-mediated reprograming of lipid metabolism in cancer

Project description:In this study transcriptome and lipidome profiling of triple negative breast cancer cells subjected to pharmacological inhibition of IRE1α revealed changes in lipid metabolism genes associated with an accumulation of triacylglycerols (TAGs). We identified DGAT2 mRNA, encoding the rate-limiting enzyme in TAG biosynthesis, as a RIDD target. Mechanistically, the DGAT2 transcript is cleaved by IRE1 at guanine 260 within a hairpin stem loop structure. Our results highlight the importance of IRE1 RIDD activity in reprograming cellular lipid metabolism

2022-02-28 | GSE176454 | GEO

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

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