Cytoplasmic proteotoxicity regulates HRI-dependent phosphorylation of eIF2a via the Hsp70-Bag3 module.
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA719638 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:The major heat shock protein Hsp70 has been shown to form a complex with a scaffold protein Bag3, linking it to multiple signaling pathways. Via these interactions, the Hsp70-Bag3 module functions as a proteotoxicity sensor that controls cell signaling. Here, as a tool to identify signaling pathways regulated by this complex, we utilized JG-98, an allosteric inhibitor of Hsp70 that blocks its interaction with Bag3. Gene expression profiling followed by the pathway analysis indicated that a set of signaling pathways including the unfolded protein response (UPR) was activated by JG-98. Surprisingly, only the translation initiation factor eIF2a-associated branch of the UPR was activated under these conditions, while other UPR branches mediating induction of ER chaperones were not induced, suggesting that the response was not related to ER proteotoxicity and thus to ER-associated kinase PERK1. Indeed, induction of the UPR genes under these conditions was dependent on activation of a distinct cytoplasmic eIF2a kinase, HRI. We demonstrated that the Hsp70-Bag3 complex directly interacted with HRI and regulated phosphorylation of eIF2a upon induction of cytoplasmic proteotoxicity. Therefore, we uncovered a novel signaling response, which regulates cell death upon the buildup of abnormal protein species in cytoplasm via an Hsp70-Bag3-HRI-eIF2a axis.
2021-04-14 | GSE171440 | GEO
Project description:To study the mitochondrial stress response HRI-eIF2a-ATF4 signaling pathway in mitochondrial cardiomyopathy , we generated Ptpmt1 cardiomyocytes-specific Knockout mcie, Eif2a mutant mcie, Gcn2 Knockout mcie, and Hri Knockout mcie
2022-04-21 | GSE201042 | GEO
Project description:Iron and heme play central roles in red blood cell production. However, the mechanisms by which iron and heme levels coordinate erythropoiesis remain incompletely understood. HRI is a heme-regulated kinase that controls translation by phosphorylating eIF2a. Here, we investigate the global impact of iron, heme and HRI on protein translation in vivo in murine primary erythroblasts using ribosome profiling. By defining the underlying changes in translation during iron and HRI deficiencies, we validate known regulators of this process, including Atf4, and identify novel pathways such as co-regulation of ribosomal protein mRNA translation. Surprisingly, we found that heme and HRI pathways, but not iron-regulated pathways, mediate the major protein translational and transcriptional responses to iron deficiency in erythroblasts in vivo and thereby identify previously unappreciated regulators of erythropoiesis. Our genome-wide study uncovers the major impact of the HRI-mediated integrated stress response for the adaptation to iron deficiency anemia.
2018-09-03 | GSE119365 | GEO
Project description:Hsp70 inhibition affects many signaling pathways. We established how these effects are translated into changes in gene expression. Hsp70 is a promising anti-cancer target, and several inhibitors of Hsp70 have been recently developed. Interest to Hsp70 inhibitors as drug prototypes is, however, somewhat hampered by potential similarity of their physiological effects to effects of already well-developed Hsp90 inhibitors. JG-98 series of inhibitors is unique in its ability to target an allosteric site in the ATPase domain of Hsp70, which disrupts its interaction with a co-chaperone Bag3 and affects a variety of signaling pathways important for cancer development and survival. Here, we used the Broad Institute Connectivity Map platform to evaluate physiological effects of JG-98, and found that these effects are dissimilar from effects of Hsp90 inhibitors, thus justifying further development of this compound series. Further, using gene expression data and ActivSignal IPAD platform, we identified pathways modulated by JG-98. Some of these pathways were affected by JG-98 in Bag3-dependent and some pathways in Bag3-independent manner, indicating multiple mechanisms of JG-98 action. Using pooled shRNA genetic screen, we established gene sets that modulate the response of cancer cells to JG-98. Based on genetic and gene expression information, we developed approaches to predict potent combinations of JG-98 with known drugs. These predictions were validated by demonstrating that proteasome, RNApol II, Akt and RTK inhibitors synergize with anti-cancer effects of JG-98. Overall, in this study we analyze unique effects of Hsp70 inhibitors of JG-98 series on cell physiology and define potential drug combinations for clinical use of these inhibitors.
2018-01-11 | GSE93542 | GEO
Project description:Cardiac-specific Bag3-P209L transgenic (Tg+) mice develop dilated cardiomyopathy by 12 months of age. The goals of this project are to utilize RNA-sequencing to compare both cardiomyocyte and cardiac fibroblast transcriptomes between aged Bag3-P209L Tg+ and Bag3-WT mice to identify cardiomyocyte and fibroblast specific gene sets that contribute to the functional and morphological changes previously identified in Bag3-P209L Tg+ hearts.
2021-06-25 | GSE116200 | GEO
Project description:Gene expression profiling of wild-type, BAG3-KO and BAG3-R477H iPSC-derived cardiomyocytes
2019-10-10 | GSE138633 | GEO
Project description:Increasing fetal hemoglobin (HbF) provides clinical benefit in patients with sickle cell disease (SCD). We recently identified heme-regulated inhibitor (HRI, EIF2AK1) as a novel HbF regulator. Since HRI is an erythroid-specific protein kinase it presents a potential target for pharmacologic intervention. We find that maximal HbF induction requires >80-85% HRI depletion. As it remains unclear whether this degree of HRI inhibition can be achieved pharmacologically, we explored whether HRI knockdown can be combined with pharmacologic HbF inducers to achieve greater HbF production and minimize potential adverse effects associated with treatments. Strongly cooperative HbF induction was observed when HRI depletion was combined with exposure to pomalidomide or the EHMT1/2 inhibitor UNC0638, but not hydroxyurea. Mechanistically, reduction in the levels of the HbF repressor BCL11A reflected the cooperativity of HRI loss and pomalidomide treatment, whereas UNC0638 did not modulate BCL11A levels. In conjunction with HRI loss, pomalidomide maintained its HbF inducing activity at 10-fold lower concentrations, at which condition there were minimal observed detrimental effects on erythroid cell maturation and viability as well as fewer alterations in the erythroid transcriptome. In sum, this study provides a foundation for the exploration of combining future small molecule HRI inhibitors with additional pharmacologic HbF inducers to maximize HbF production and preserve erythroid cell functionality for the treatment of SCD and other hemoglobinopathies.
2020-09-21 | GSE150341 | GEO
Project description:Hyperthermia (HT) treatments in combination with either chemotherapy, radiotherapy or both are used for patients with cancer in various organs. However, the acquisition of thermotolerance in cancer cells due to the increase in cytoprotective proteins attenuates the therapeutic effects of HT. BAG3 (BCL2-associated athanogene 3) is a cytoprotective protein that acts against various stresses including heat stress. Recently, we demonstrated that the inhibition of BAG3 improves cell death sensitivity to HT in cancer cells. However, a detailed molecular mechanism involved in the enhancement of HT sensitivity by BAG3-knockdown (KD) in cancer cells is unclear. In this study, to identify genes involved in the enhancement of HT sensitivity by BAG3-knockdown (KD) in cancer cells, global-scale gene expression analysis was carried out using a GeneChip® system. Human oral squamous carcinoma cell HSC-3 cells were treated with a combination of HT (at 44°C for 90 min) and siRNA for BAG3 or luciferase. Total RNA samples were prepared from the cells, and quality of the RNA was analyzed using a Bioanalyzer 2100. Gene expression was analyzed by an Affymetrix GeneChip® system with a Human Genome U133-plus 2.0 array. Sample preparation for array hybridization was carried out as described in the manufacturerâs instructions.
2015-11-19 | E-GEOD-75127 | biostudies-arrayexpress
Project description:BAG3 (BCL2-associated athanogene 3) is a member of the BAG protein family. BAG3 affects a wide variety of cellular events including cell proliferation, apoptosis and autophagy. Recently our data demonstrated that knockout (KO) of BAG3 induces the cell growth arrest in human cervical carcinoma HeLa cells. In the present study, to identify genes involved in the cell growth arrest by BAG3-KO in HeLa cells, global-scale gene expression analysis was carried out using a GeneChip® system.
2017-09-06 | GSE103475 | GEO