An HSF1-JMJD6-HSP feedback circuit promotes cell adaptation to proteotoxic stress [RNA-Seq]
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ABSTRACT:
PROVIDER: PRJNA1127665 | ENA |
REPOSITORIES: ENA
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Project description:Heat Shock Factor 1 (HSF1) is best known as the master transcriptional regulator of the heat-shock response (HSR), a conserved adaptive mechanism critical for protein homeostasis (proteostasis). Combining a genome-wide RNAi library with an HSR reporter, we identified JMJD6 as an essential mediator of HSF1 activity. In follow-up studies, we found that JMJD6 is itself a non-canonical transcriptional target of HSF1 which acts as a critical regulator of proteostasis. In a positive feedback circuit, HSF1 binds and promotes JMJD6 expression, which in turn reduces HSP70 R469 monomethylation to disrupt HSP70-HSF1 repressive complexes resulting in enhanced HSF1 activation. Thus, JMJD6 is intricately wired into the proteostasis network where it plays a critical role for cellular adaptation to proteotoxic stress.
2024-07-18 | GSE270672 | GEO
Project description:Heat Shock Factor 1 (HSF1) is best known as the master transcriptional regulator of the heat-shock response (HSR), a conserved adaptive mechanism critical for protein homeostasis (proteostasis). Combining a genome-wide RNAi library with an HSR reporter, we identified JMJD6 as an essential mediator of HSF1 activity. In follow-up studies, we found that JMJD6 is itself a non-canonical transcriptional target of HSF1 which acts as a critical regulator of proteostasis. In a positive feedback circuit, HSF1 binds and promotes JMJD6 expression, which in turn reduces HSP70 R469 monomethylation to disrupt HSP70-HSF1 repressive complexes resulting in enhanced HSF1 activation. Thus, JMJD6 is intricately wired into the proteostasis network where it plays a critical role for cellular adaptation to proteotoxic stress.
2024-07-18 | GSE270671 | GEO
Project description:An HSF1-JMJD6-HSP feedback circuit promotes cell adaptation to proteotoxic stress [ChIP-Seq]
| PRJNA1127661 | ENA
Project description:Leiomyosarcoma (LMS) is an aggressive cancer with few therapeutic options. LMS cells are more sensitive to proteotoxic stress compared to normal smooth muscle cells. We used small compound 2c to induce proteotoxic stress and compare the transcriptomic adaptations of immortalized human uterine smooth muscle cells (HUtSMC) and LMS cells SK-UT-1. We found that the expression of the heat shock proteins (HSP) gene family is upregulated with higher efficiency in normal cells. In contrast, upregulation of BH3-only proteins is higher in LMS cells. HSF1, the master regulator of HSP transcription, is sequestered into transcriptionally incompetent nuclear foci only in LMS cells, which explains the lower HSP upregulation. We also found that several compounds can enhance the cell death response to proteotoxic stress. Specifically, when low doses were used, an inhibitor of salt-inducible kinases (SIKs) and the inhibitor of IRE1, a key element of the unfolded protein response (UPR), support proteotoxic-induced cell death with strength in LMS cells and without effects on the survival of normal cells. Overall, our data provide an explanation for the higher susceptibility of LMS cells to proteotoxic stress and suggest a potential option for co-treatment strategies.
2022-10-03 | GSE205596 | GEO
Project description:The heat shock response is a universal transcriptional response to proteotoxic stress orchestrated by heat shock transcription factor Hsf1 in all eukaryotic cells. Despite over 40 years of intense research, the mechanism of HSF1 activity regulation remains poorly understood at a molecular level. In metazoa Hsf1 trimerizes upon heat shock through a leucin-zipper domain and binds to DNA. How Hsf1 is dislodged from DNA and monomerized remained enigmatic. Here, using purified proteins we demonstrate that unmodified trimeric Hsf1 is dissociated from DNA in vitro by Hsc70 and DnaJB1. Hsc70 binds to multiple sites in Hsf1 with different affinities. Hsf1 trimers are monomerized by successive cycles of entropic pulling, unzipping the triple leucinezipper. Starting this unzipping at several protomers of the Hsf1 trimer results in faster monomerization. This process directly monitors the concentration of Hsc70 and DnaJB1. During heat shock adaptation Hsc70 first binds to a high affinity site in the transactivation domain leading to partial attenuation of the response and subsequently, at higher concentrations, Hsc70 removes Hsf1 from DNA to restore the resting state.
2020-06-22 | PXD017406 | Pride
Project description:Stress responses are a key feature of normal physiology and are usurped by cancer cells to ensure enhanced protein synthesis for growth, to compensate for genomic instability, and to protect cancer cells from therapy induced stress. Heat shock factor-1 (HSF1) is a major stress-response transcription factor, and its activity is markedly enhanced in cancer. Stress induces HSF1 conformational changes and post-translational modifications, leading to assembly of active HSF1 trimers that bind DNA to control target gene expression. Although the function of HSF1 in transcription is relatively well-known, the mechanisms leading to HSF1 activation and enhanced stress response in tumours are unclear. To investigate whether HSF1 is a primary sensor of proteotoxic stress in vivo, we studied the range of conditions that can cause HSF1 activation in vitro and in cells, and conditions that prevent its activation. We show that purified recombinant HSF1 adopts a stable monomeric conformation in vitro. Heat stress caused a conformational change and the assembly of HSF1 trimers. Conditions leading to protein denaturation, including heat stress, crowding, Hsp90 inhibition, or proteasome inhibition, all directly lead to HSF1 activation. In contrast, HSF1 activation in vivo is prevented by proteosynthesis inhibition, which reduces the amount of denatured proteins in the cell. These results establish that HSF1 is a direct sensor of proteotoxic stress, independent of post-translational modification, where abrupt environmental changes that cause protein denaturation simultaneously induce a conformational change in monomeric HSF1 leading to its activation. This mechanism explains the universal ability of cells to respond to proteotoxic stress and trigger a protective response when increased chaperone activities are required to restore homeostasis.
2024-08-14 | PXD037662 | Pride
Project description:Heat shock transcription factor 1 (HSF1) regulates the expression of a wide array of genes, controlling expression of heat shock proteins (HSPs) and cell growth. Although acute depletion of HSF1 induces cellular senescence, the underlying mechanisms are poorly understood. Here, we report that HSF1 depletion-induced senescence (HDIS) of human diploid fibroblasts (HDFs) was independent of HSP-mediated proteostasis, but dependent on activation of the p53-p21 pathway, partly because of increased expression of dehydrogenase/reductase 2 (DHRS2), a putative MDM2 inhibitor. We observed that HDIS occurred without decreased levels of major HSPs or increased proteotoxic stress in HDFs. Additionally, an inhibitor of HSP70 family proteins increased proteotoxicity and suppressed cell growth, but failed to induce senescence. Importantly, we found that activation of the p53-p21 pathway due to reduced MDM2-dependent p53 degradation was required for HDIS. Furthermore, we provide evidence that increased DHRS2 expression contribute to p53 stabilization and HDIS. Collectively, our observations uncovered a molecular pathway in which HSF1 depletion-induced DHRS2 expression leads to activation of the MDM2-p53-p21 pathway required for HDIS.
2018-05-01 | GSE111355 | GEO
Project description:Diverse cellular insults converge on activation of the heat shock factor 1 (HSF1), which regulates the proteotoxic stress response to maintain protein homoeostasis. HSF1 regulates numerous gene programmes beyond the proteotoxic stress response in a cell-type- and context-specific manner to promote malignancy. However, the role(s) of HSF1 in immune populations of the tumour microenvironment remain elusive. Here, we leverage an in vivo model of HSF1 activation and single-cell transcriptomic tumour profiling to show that augmented HSF1 activity in natural killer (NK) cells impairs cytotoxicity, cytokine production, and subsequent anti-tumour immunity. Mechanistically, HSF1 directly binds and regulates the expression of key mediators of NK cell effector function. This work demonstrates that HSF1 regulates the immune response under the stress conditions of the tumour microenvironment. These findings have important implications for enhancing the efficacy of adoptive NK cell therapies and for designing combinatorial strategies including modulators of NK cell-mediated tumour killing. This SuperSeries is composed of the SubSeries listed below.
2021-02-26 | GSE167552 | GEO
Project description:We investigated whether interfering with HSF1 LLPS affected the expression of its target genes using RNA sequencing. We found HS induced HSPs gene expression in LLPS-dependent manner. LLPS-dependent gene activation was also observed in M1 cells under NHS condition. In addition, LLPS-incompetent M3 infected cells showed less HSP gene expression even under HS condition. Thus, these data collectively support a crucial role for LLPS of HSF1 in activating HSP genes expression.
2021-12-19 | GSE191134 | GEO
Project description:The Jumonji domaining-containing protein JMJD6 is a 2-oxoglutarate dependent dioxygenase that has been implicated in a broad range of biological functions. Cellular studies have implicated the enzyme in chromatin biology, transcription, DNA repair, mRNA splicing and co-transcriptional processing. Although not all studies agree, JMJD6 has been reported to catalyse both hydroxylation of lysine residues and demethylation of arginine residues. However, despite extensive study and the indirect implication of JMJD6 catalysis in many cellular processes, direct assignment of JMJD6 catalytic substrates has been limited. Examination of a site of reported prolyl hydroxylation within a lysine-rich region of the bromodomain protein BRD4 led us to conclude that hydroxylation was in fact on lysine and catalysed by Jmjd6. This prompted a wider search for JMJD6-catalysed protein modifications deploying mass spectrometric methods designed to identify novel substrate associations and facilitate analysis of lysine-rich regions by LC-MSMS. Using derivatization of lysine with propionic anhydride to improve the analysis of tryptic peptides and a pharmacological inhibitor of JMJD6 to stabilise enzyme/substrate associations, we report over 100 sites of JMJD6-catalysed lysyl hydroxylation on 48 protein substrates including 19 sites of hydroxylation on BRD4. Most hydroxylations were within lysine-rich regions that are predicted to be unstructured; in some multiple modifications were observed on adjacent lysine residues. Almost all of the JMJD6 substrates defined in this study have been associated with membraneless organelle formation. Taken together with findings implicating lysine-rich regions in subcellular partitioning by liquid-liquid phase separation, our findings raise the possibility that JMJD6 may play a role in regulating such processes in response to stresses, including hypoxia. Note, this dataset corresponds to Figure 3 of the published manuscript; which employs a substrate-trapping methodology to identify novel substrates of JMJD6 by label free DIA approach.
2022-08-02 | PXD031155 | Pride