Chromatin occupancy of ATF4 at day 1 of cardiomyocytes differentiation [ChIP-seq]
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE188112 | GEO | 2023/06/30
REPOSITORIES: GEO
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Project description:Cardiac development involves large-scale rearrangements of the proteome. How the developing cardiac cells maintain the integrity of the proteome during the rapid lineage transition remains unclear. Here we show that proteotoxic stress visualized by the misfolded protein aggregates appears during early cardiac differentiation of human embryonic stem cells (hESCs) and is resolved by activation of the PERK branch of the unfolded protein response (UPR). PERK depletion increases misfolded protein accumulation, leading to pluripotency exit defect and impaired mesendoderm specification of hESCs. Mechanistically, we found that PERK safeguards cardiogenesis through its conserved downstream effector ATF4, which subsequently activates a novel transcriptional target WARS1, to cope with the differentiation-induced proteotoxic stress. Our results indicate that protein quality control represents a previously unrecognized core component of the cardiogenic regulatory network. Broadly, these findings provide a framework for understanding how UPR is integrated into the developmental program by activating the PERK-ATF4-WARS1 axis.
2023-06-30 | GSE188111 | GEO
Project description:Disruptions of protein homeostasis in the endoplasmic reticulum (ER) elicit activation of the unfolded protein response (UPR), a translation- and transcription-coupled proteostatic stress response pathway. The primary translational control arm of the UPR is initiated by the PERK-dependent phosphorylation of eIF2α, leading to a large-scale reprogramming of translation and subsequent activation of an ATF4-mediated transcriptional program. It has remained challenging, however, to accurately evaluate the contribution of each component of the eIF2α/ATF4 pathway to the remodelling of transcription and translation. Here, we have used mouse embryonic fibroblasts containing either a knock-in of the non-phosphorylatable eIF2α S51A mutant or knock-out for ATF4 by ribosome profiling and mRNA-seq to define the specific contributions of eIF2α phosphoryation and ATF4 in controlling the translational and transcriptional components of the UPR. These studies show that the transcriptional and translational targets of each P-eIF2α, ATF4, and the other UPR gene expression programs overlapped extensively, leading to a core set of UPR genes whose robust expression in response to ER stress is driven by multiple mechanisms. The identification of other, more factor-specific targets illustrated the potential for functional specialization of the UPR. As the UPR progressed temporally, cells employed distinct combinations of transcriptional and translational mechanisms, initiated by different factors, to adapt to ongoing stress. These effects were accompanied by a buffering effect where changes in mRNA levels were coupled to opposing changes in ribosome loading, a property which makes cooperation between transcription and translation essential to confer robust protein expression. Translational analysis by ribosome profiling and mRNA-seq of PERK pathways mutants during the UPR. Mouse embryonic fibroblasts (MEFs) lacking components of the PERK pathway (eIF2a phosphorylation and ATF4) were subjected to ER stress and analyzed by ribosome profiling.
2016-07-03 | E-GEOD-68265 | biostudies-arrayexpress
Project description:Disruptions of the endoplasmic reticulum (ER) that perturb protein folding cause ER stress and elicit an unfolded protein response (UPR) that involves translational and transcriptional changes in gene expression aimed at expanding the ER processing capacity and alleviating cellular injury. Three ER stress sensors PERK, ATF6, and IRE1 implement the UPR. PERK phosphorylation of eIF2 during ER stress represses protein synthesis, which prevents further influx of ER client proteins, along with preferential translation of ATF4, a transcription activator of the integrated stress response. In this study we show that the PERK/eIF2α~P/ATF4 pathway is required not only for translational control, but also activation of ATF6 and its target genes. The PERK pathway facilitates both the synthesis of ATF6 and trafficking of ATF6 from the ER to the Golgi for intramembrane proteolysis and activation of ATF6. As a consequence, liver-specific depletion of PERK significantly reduces both the translational and transcriptional phases of the UPR, leading to reduced protein chaperone expression, disruptions of lipid metabolism, and enhanced apoptosis. These findings show that the regulatory networks of the UPR are fully integrated, and helps explain the diverse pathologies associated with loss of PERK. 14 gene expression arrays, 3 WT control arrays; 3 lsPERK control arrays; 4 WT Treated arrays; 4 lsPERK treated arrays. Comparison of gene expression profiles for treated vs control in wildtype and knock-out.
2012-01-20 | E-GEOD-29929 | biostudies-arrayexpress
Project description:Disruptions of the endoplasmic reticulum (ER) that perturb protein folding cause ER stress and elicit an unfolded protein response (UPR) that involves translational and transcriptional changes in gene expression aimed at expanding the ER processing capacity and alleviating cellular injury. Three ER stress sensors PERK, ATF6, and IRE1 implement the UPR. PERK phosphorylation of eIF2 during ER stress represses protein synthesis, which prevents further influx of ER client proteins, along with preferential translation of ATF4, a transcription activator of the integrated stress response. In this study we show that the PERK/eIF2α~P/ATF4 pathway is required not only for translational control, but also activation of ATF6 and its target genes. The PERK pathway facilitates both the synthesis of ATF6 and trafficking of ATF6 from the ER to the Golgi for intramembrane proteolysis and activation of ATF6. As a consequence, liver-specific depletion of PERK significantly reduces both the translational and transcriptional phases of the UPR, leading to reduced protein chaperone expression, disruptions of lipid metabolism, and enhanced apoptosis. These findings show that the regulatory networks of the UPR are fully integrated, and helps explain the diverse pathologies associated with loss of PERK.
2012-01-20 | GSE29929 | GEO
Project description:The accumulation of misfolded proteins in the endoplasmic reticulum (ER) defines a condition called ER stress that induces the unfolded protein response (UPR). The UPR in mammalian cells attenuates protein synthesis initiation, which prevents the piling up of misfolded proteins in the ER. Mammalian cells rely on Protein Kinase RNA-Like Endoplasmic Reticulum Kinase (PERK) phosphorylation of eIF2alpha to arrest protein synthesis, however, plants do not have a PERK homolog, so the question is whether plants control translation in response to ER stress. We compared changes in RNA levels in the transcriptome to the RNA levels protected by ribosomes and found a decline in translation efficiency, including many UPR genes, in response to ER stress. The decline in translation efficiency is due to the fact that many mRNAs are not loaded onto polyribosomes (polysomes) in proportion to their increase in total RNA, instead some of the transcripts accumulate in stress granules (SGs). The RNAs that populate SGs are not derived from the disassembly of polysomes because protein synthesis remains steady during stress. Thus, the surge in transcription of UPR genes in response to ER stress is accompanied by the formation of SGs, and the sequestration of mRNAs in SGs may serve to temporarily relieve the translation load during ER stress.
2020-07-08 | GSE153969 | GEO
Project description:Disruptions of protein homeostasis in the endoplasmic reticulum (ER) elicit activation of the unfolded protein response (UPR), a translation- and transcription-coupled proteostatic stress response pathway. The primary translational control arm of the UPR is initiated by the PERK-dependent phosphorylation of eIF2α, leading to a large-scale reprogramming of translation and subsequent activation of an ATF4-mediated transcriptional program. It has remained challenging, however, to accurately evaluate the contribution of each component of the eIF2α/ATF4 pathway to the remodelling of transcription and translation. Here, we have used mouse embryonic fibroblasts containing either a knock-in of the non-phosphorylatable eIF2α S51A mutant or knock-out for ATF4 by ribosome profiling and mRNA-seq to define the specific contributions of eIF2α phosphoryation and ATF4 in controlling the translational and transcriptional components of the UPR. These studies show that the transcriptional and translational targets of each P-eIF2α, ATF4, and the other UPR gene expression programs overlapped extensively, leading to a core set of UPR genes whose robust expression in response to ER stress is driven by multiple mechanisms. The identification of other, more factor-specific targets illustrated the potential for functional specialization of the UPR. As the UPR progressed temporally, cells employed distinct combinations of transcriptional and translational mechanisms, initiated by different factors, to adapt to ongoing stress. These effects were accompanied by a buffering effect where changes in mRNA levels were coupled to opposing changes in ribosome loading, a property which makes cooperation between transcription and translation essential to confer robust protein expression.
2016-01-01 | GSE68265 | GEO
Project description:Accumulation of unfolded or misfolded proteins in the endoplasmic reticulum (ER) lumen triggers unfolded protein response (UPR) for stress adaptation, the failure of which induces cell apoptosis and tissue/organ damage. The molecular switches underlying how the UPR selects for stress adaptation over apoptosis remain unknown. Here we discovered that accumulation of unfolded/misfolded proteins selectively induces N6-adenosine-methyltransferase-14 (METTL14) expression. METTL14 promotes CHOP mRNA decay through its 3’UTR N6-adenosine methylation (m6A) to inhibit its downstream pro-apoptotic target genes expression. UPR induces METTL14 expression through competing the HRD1-ERAD machinery to block METTL14 ubiquitination and degradation. Therefore, mice with liver-specific METTL14 deletion are highly susceptible to both acute pharmacological and alpha-1 antitrypsin (AAT) deficiency-induced ER proteotoxic stress and liver injury. Further hepatic CHOP deletion protects METTL14 knockout mice from ER stress-induced liver damage. Our study reveals a crosstalk between ER stress and mRNA m6A pathways, the ERm6A pathway, for ER stress adaptation to proteotoxicity.
2021-09-30 | GSE185109 | GEO
Project description:Olfactory sensory neurons (OSNs) transform the stochastic choice of one out of >1000 olfactory receptor (OR) genes into precise and stereotyped axon targeting of OR-specific glomeruli in the olfactory bulb. Here, we show that the PERK arm of the unfolded protein response (UPR) regulates both the glomerular coalescence of like axons, and the specificity of their projections. Subtle differences in OR protein sequences lead to distinct patterns of endoplasmic reticulum (ER) stress during OSN development, converting OR identity into distinct gene expression signatures. We identify the transcription factor Ddit3 as a key effector of PERK signaling that maps OR-dependent ER signaling patterns to the transcriptional regulation of axon guidance and cell adhesion genes, instructing targeting precision. Our results extend the known functions of the UPR from a quality control pathway that protects cells from misfolded proteins, to a sensor of cellular identity that interprets physiological states to direct axon wiring.
2022-09-26 | GSE198886 | GEO
Project description:Mutations in myelin protein zero (MPZ) are generally associated with Charcot-Marie-Tooth type 1B (CMT1B) disease, one of the most common forms of demyelinating neuropathy. Pathogenesis of some MPZ mutants, such as S63del and R98C, involves protein misfolding and retention in the endoplasmic reticulum (ER) of myelinating Schwann cells. To cope with proteotoxic ER-stress, Schwann cells mount an unfolded protein response (UPR) characterized by activation of the PERK, ATF6 and IRE1/XBP1 pathways. Previous studies have reported that targeting PERK pathway can mitigate the neuropathy in CMT1B mice. To unravel the role of the XBP1 pathway in normal myelination and in CMT1B, we generated mouse models of in which XBP1 is deleted specifically in Schwann cells. We observed that whereas XBP1 is dispensable for normal developmental myelination, myelin maintenance and remyelination after injury, the absence of XBP1 dramatically worsens the hypomyelination and the electrophysiological and locomotor parameters in young and adult CMT1B neuropathic animals. RNAseq analysis suggested that XBP1 exerts its adaptive function in large part via the induction of genes involved in misfolded protein degradation. Accordingly, the exacerbation of the neuropathy was accompanied by upregulation of ER-stress pathways and of IRE1-mediated RIDD signaling, suggesting that the activation of XBP1 plays a critical role in limiting mutant proteins toxicity, which cannot be compensated by other stress responses. Schwann cell specific overexpression of spliced XBP1 partially re-established Schwann cell proteostasis and attenuated CMT1B severity in vivo in both the S63del and R98C mouse models. In addition, the pharmacologic selective activation of XBP1 signaling ameliorated myelination in S63del dorsal root ganglia explants.
2024-01-15 | GSE252089 | GEO
Project description:Here we report that the Th2 cytokine IL-4 and the tumor microenvironment activated protein kinase RNA-like ER kinase (PERK) ER stress signaling cascade to promote immunosuppressive M2 activation and proliferation. Lacking PERK signaling impeded mitochondrial respiration and lipid oxidation critical for M2 macrophages. In addition, PERK activation mediated the upregulation of PSAT1 and serine biosynthesis via the downstream transcription factor ATF4.
2022-01-01 | GSE165836 | GEO