FAM69C promotes stress granule assembly and suppresses inflammasome activation
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE214646 | GEO | 2022/10/05
REPOSITORIES: GEO
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Project description:Stress granules are dynamic cytoplasmic ribonucleoprotein granules that assemble in response to cellular stress. Aberrant formation of stress granules has been linked to neurodegenerative diseases. However, the molecular mechanisms underlying the initiation of stress granules remain elusive. Here we report that the brain-enriched protein kinase FAM69C promotes stress granule assembly through phosphorylation of eukaryotic translation initiation factor 2 (eIF2α). FAM69C physically interacts with eIF2α and functions as a stress-specific kinase for eIF2α, leading to stress-induced protein translation arrest and stress granule assembly. Primary microglia derived from Fam69c knockout mice exhibit aberrant stress granule assembly in response to oxidative stress and ATP. Defective stress granule assembly in microglia correlates with the formation of ASC specks and NLRP3 inflammasome activation, whereas induction of stress granule precludes inflammasome formation. Consistently, increased NLRP3 levels, caspase-1 cleavage and Il18 expression corroborate microglia-associated neuroinflammation in aged Fam69c knockout mice. Our study demonstrates that FAM69C is critical for stress granule assembly and suggests its role in the regulation of microglia function.
2023-04-21 | PXD037697 | Pride
Project description:All cells and organisms exhibit stress-coping mechanisms to ensure survival. Cytoplasmic protein-RNA assemblies termed stress granules are increasingly recognized to promote cellular survival under stress. Thus, they might represent tumor vulnerabilities that are currently poorly explored. The translation-inhibitory eIF2α kinases are established as main drivers of stress granule assembly. Using a systems approach, we identify the translation enhancers PI3K and MAPK/p38 as pro-stress-granule-kinases. They act through the metabolic master regulator mammalian target of rapamycin complex 1 (mTORC1) to promote stress granule assembly. When highly active, PI3K is the main driver of stress granules; however, the impact of p38 becomes apparent as PI3K activity declines. PI3K and p38 thus act in a hierarchical manner to drive mTORC1 activity and stress granule assembly. Of note, this signaling hierarchy is also present in human breast cancer tissue. Importantly, only the recognition of the PI3K-p38 hierarchy under stress enabled the discovery of p38’s role in stress granule formation. In summary, we assign a new pro-survival function to the key oncogenic kinases PI3K and p38, as they hierarchically promote stress granule formation.
2020-01-03 | MODEL2001030002 | BioModels
Project description:All cells and organisms exhibit stress-coping mechanisms toensure survival. Cytoplasmic protein-RNA assemblies termedstress granules are increasingly recognized to promote cellularsurvival under stress. Thus, they might represent tumor vul-nerabilities that are currently poorly explored. The translation-inhibitory eIF2αkinases are established as main drivers ofstress granule assembly. Using a systems approach, we identifythe translation enhancers PI3K and MAPK/p38 as pro-stress-granule-kinases. They act through the metabolic master regu-lator mammalian target of rapamycin complex 1 (mTORC1) topromote stress granule assembly. When highly active, PI3K is themain driver of stress granules; however, the impact of p38becomes apparent as PI3K activity declines. PI3K and p38 thusact in a hierarchical manner to drive mTORC1 activity and stressgranule assembly. Of note, this signaling hierarchy is also presentin human breast cancer tissue. Importantly, only the recognition ofthe PI3K-p38 hierarchy under stress enabled the discovery of p38’srole in stress granule formation. In summary, we assign a new pro-survival function to the key oncogenic kinases PI3K and p38, as theyhierarchically promote stress granule formation
2020-01-03 | BIOMD0000000907 | BioModels
Project description:The cellular stress response plays a vital role in regulating homeostasis by modulating cell survival and death. Stress granules (referred to as SGs) are cytoplasmic compartments that allow cells to survive various stressors. Defects in SG assembly and disassembly have been found to play important roles in neurodegenerative diseases, antiviral responses and cancer1–5. Inflammasomes are multi-protein heteromeric complexes that sense intracellular pathogen- and damage-associated molecular patterns and assemble into cytosolic compartments called ASC specks to facilitate caspase-1 (CASP1) activation. This activation of inflammasomes induces secretion of the leaderless proinflammatory cytokines IL-1β and IL-18 and also drives cell fate towards pyroptosis, a form of programmed inflammatory cell death that plays major role in health and disease6–12. Cellular stress sensing can trigger both SGs and inflammasomes; however, they drive contrasting cell fate decisions during stress conditions. Crosstalk between SGs and inflammasomes to decide cell fate has not been well studied. Here we show that the induction of SGs specifically inhibits NLRP3 inflammasome activation, ASC speck formation and pyroptosis. The SG protein DDX3X interacts with NLRP3 to drive inflammasome activation in the absence of SGs. Assembly of SGs leads to the sequestration of DDX3X to inhibit NLRP3 inflammasome function. SGs and the NLRP3 inflammasome compete for DDX3X molecules to coordinate the activation of innate responses and subsequent cell fate decisions under stress conditions. Induction of SGs or loss of DDX3X in the myeloid compartment leads to decreased production of inflammasome-dependent cytokines in vivo. Our findings suggest that macrophages utilize DDX3X availability to interpret stress signals and choose between pro-survival SGs and pyroptotic ASC specks. Together, our data show the role of DDX3X in driving NLRP3 inflammasome and SG assembly, informing a new rheostat-like mechanistic paradigm for regulating live or die cell fate decisions under stress conditions.
2019-10-03 | PXD014828 | Pride
Project description:Ribonucleoprotein (RNP) granules are non-membrane bound organelles thought to assemble by protein-protein interactions of RNA-binding proteins. We present evidence that a wide variety of RNAs self-assemble in vitro into either liquid-liquid phase separations or more stable assembles, referred to as RNA tangles. Self-assembly in vitro is affected by RNA length, ionic conditions, and sequence. Remarkably, self-assembly of yeast RNA in vitro under physiological salt mimics the composition of mRNAs within yeast stress granules. This suggests that the biophysical principles that drive RNA self-assembly in vitro contribute to determining the stress granule transcriptome. Consistent with RNA self-assembly contributing to RNP granule formation, an excess of purified RNA injected into C. elegans syncytium coalesces into droplet-like assemblies. We suggest that diverse RNA-RNA interactions in trans contribute to RNP granule formation and may explain the prevalence of large RNA-protein assemblies in eukaryotic cells.
2017-05-23 | GSE99170 | GEO
Project description:Low complexity “prion-like” domains in key RNA-binding proteins (RBPs) mediate the reversible assembly of RNA granules. Individual RBPs harboring these domains have been linked to specific neurodegenerative diseases. Although their aggregation in neurodegeneration has been extensively characterized, it remains unknown how the process of aging disturbs RBP dynamics. We show that a wide variety of RNA granule components including stress granule proteins become highly insoluble with age in C. elegans and that reduced insulin/IGF-1 daf-2 receptor signaling efficiently prevents their aggregation. Importantly, stress granule-related RBP aggregates are associated with reduced fitness. We show that HSF-1 is a main regulator of stress granule-related RBP aggregation in both young and aged animals. During aging, increasing DAF-16 activity restores dynamic stress granule-related RBPs partly by reducing the build-up of other misfolded proteins that seed RBP aggregation. Longevity-associated mechanisms found to maintain dynamic RBPs during aging could be relevant for neurodegenerative diseases.
2017-01-16 | PXD003451 | Pride
Project description:Cytoplasmic RNA granules have emerged as important elements of posttranscriptional and translational regulation. Stress, germinal and neuronal granules contain RNA-binding proteins capable of self-assembly due to prion-like domains. Hyperassembly mediated by these prion-like domains causes several neurodegenerative diseases. Here, we report a subset of the mammalian prion protein (PrP), also prone to self-assembly, propagation and to cause devastating diseases, is a component of naturally occurring messenger ribonucleoproteins (mRNPs) in adult mouse brains. Biomolecules co-purified with PrP revealed a multitude of diverse RNA granule associated proteins and mRNAs encoding members of the translation machinery, indicating a role in a specialized translation process. Importantly, PrP mutations linked to Creutzfeldt-Jakob disease (CJD) or fatal familial insomnia (FFI) severely impaired recovery of mRNPs from preclinical mice, possibly representing a very early pathological process. Thus, mutant PrP may cause dysfunction in RNA regulation, thereby joining the constantly expanding ranks of disease associated RNP granule proteins. The file Enrichment_analysis.xlsx contains mRNAs (FDR < 0.01) co-purified with PrP in both WT sample pools as identified by DESeq2 and the respective gene counts and log2 fold changes for CJD and FFI PrP:IP sample pools.
2015-11-01 | GSE57233 | GEO
Project description:Stress granules are small RNA-protein granules that modify the translational landscape during cellular stress to promote survival. The RhoGTPase RhoA is implicated in the formation of RNA stress granules. Our data demonstrate that the cytokinetic proteins ECT2 and AurkB are localized to stress granules in human astrocytoma cells. AurkB and its downstream target histone-3 are phosphorylated during arsenite-induced stress. Chemical (AZD1152-HQPA) and siRNA inhibition of AurkB results in fewer and smaller stress granules when analyzed utilizing high throughput fluorescent based cellomics assays. RNA immunoprecipitation with the known stress granule aggregates TIAR and G3BP1 was performed on astrocytoma cells and subsequent analysis revealed that astrocytoma stress granules harbour unique mRNAs for various cellular pathways including cellular migration, metabolism, translation and transcriptional regulation. Human astrocytoma cell stress granules contain mRNA that are known to be involved in glioma signaling and the mTOR pathway. These data provide evidence that RNA stress granules are a novel form of epigenetic regulation in astrocytoma cells, which may be targetable by chemical inhibitors and enhance astrocytoma susceptiblity to conventional therapy such as radiation and chemotherapy. Astrocytoma cells were either untreated or treated with arsenite to induce stress granule formation and RNA immunoprecipitates were analyzed by exon array analysis. RNA species that were enriched in TIAR RIPs and G3BP1 RIPS, respectively were compared to compared to TIAR and G3BP1 RIPs from untreated cells and input controls. Ingenuity pathway analysis was performed on the stress granule enriched mRNAs from the TIAR and G3BP1 RIPs to identify significant functional biology networks.
2016-02-29 | E-GEOD-76814 | biostudies-arrayexpress
Project description:Cytoplasmic RNA granules have emerged as important elements of posttranscriptional and translational regulation. Stress, germinal and neuronal granules contain RNA-binding proteins capable of self-assembly due to prion-like domains. Hyperassembly mediated by these prion-like domains causes several neurodegenerative diseases. Here, we report a subset of the mammalian prion protein (PrP), also prone to self-assembly, propagation and to cause devastating diseases, is a component of naturally occurring messenger ribonucleoproteins (mRNPs) in adult mouse brains. Biomolecules co-purified with PrP revealed a multitude of diverse RNA granule associated proteins and mRNAs encoding members of the translation machinery, indicating a role in a specialized translation process. Importantly, PrP mutations linked to Creutzfeldt-Jakob disease (CJD) or fatal familial insomnia (FFI) severely impaired recovery of mRNPs from preclinical mice, possibly representing a very early pathological process. Thus, mutant PrP may cause dysfunction in RNA regulation, thereby joining the constantly expanding ranks of disease associated RNP granule proteins. The file Enrichment_analysis.xlsx contains mRNAs (FDR < 0.01) co-purified with PrP in both WT sample pools as identified by DESeq2 and the respective gene counts and log2 fold changes for CJD and FFI PrP:IP sample pools. RIP-Seq analysis of mRNAs co-purified with PrP from murine brain cytoplasmic fractions in wild-type (WT), CJD and FFI mice. Each RIP-Seq and control (input) library represents a pool of 12 to 16 co-immunoprecipitation samples out of 3 to 4 mice. To control for post-homogenization artifacts, we conducted an experiment in which we prepared homogenates from WT and PrP-KO (Prnp-/-) mice of different genetic backgrounds (C57BL/6 and 129S4) and identified SNPs in RIP-Seq and control libraries to finally identify specifically co-purified mRNAs.
2015-11-01 | E-GEOD-57233 | biostudies-arrayexpress
Project description:The eukaryotic cytosol contains multiple RNP granules including P-bodies and stress granules. Three different methods have been used to describe the transcriptome of stress granules or P-bodies, but how these methods compare, and how RNA partitioning occurs between P-bodies and stress granules has not been addressed. Herein, we compare the analysis of the stress granule transcriptome based on differential centrifugation, with and without subsequent stress granule immunopurification. We find that while differential centrifugation alone gives a first approximation of the stress granule transcriptome, this methodology contains non-specific transcripts that play a confounding role in the interpretation of results. We also immunopurify and compare the RNAs in stress granules and P-bodies under arsenite stress and compare those results to the P-body transcriptome described under non-stress conditions. We find that the P-body transcriptome is dominated by poorly translated mRNAs under non-stress conditions, but during arsenite stress, when translation is globally repressed, the P-body transcriptome is very similar to the stress granule transcriptome. This suggests that translation is a dominant factor in targeting mRNAs into both P-bodies and stress granules, and during stress, when most mRNAs are untranslated, the composition of P- bodies reflects this broader translation repression.
2019-10-17 | GSE138988 | GEO