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Thermoprotection in the Drosophila hsf4 mutant

ABSTRACT: In Drosophila larvae, acquired synaptic thermotolerance following heat shock has previously been shown to correlate with the induction of heat shock proteins (Hsps) including HSP70. We tested the hypothesis that synaptic thermotolerance would be significantly diminished in a temperature-sensitive strain (hsf4) which has been reported not to be able to produce inducible Hsps in response to heat shock. Contrary to our hypothesis, considerable thermoprotection was still observed at hsf4 larval synapses following heat shock. To investigate the cause of this thermoprotection, we conducted DNA microarray experiments to identify heat-induced transcript changes in these organisms. Transcripts of the hsp83, dnaJ-1(hsp40) and gstE1 genes were significantly up-regulated in hsf4 larvae after heat shock. In addition, increases in the levels of Hsp83 and DnaJ-1 proteins but not in the inducible form of Hsp70 were detected by Western blotting. The mode of heat shock administration differentially affected the relative transcript and translational changes for these chaperones. These results indicate that the compensatory up-regulation of constitutively expressed Hsps, in the absence of the synthesis of inducible Hsps including HSP70, could still provide substantial thermoprotection to both synapses and the whole organism. Keywords: heat shock response

ORGANISM(S): Drosophila melanogaster

PROVIDER: GSE2998 | GEO | 2005/12/01

SECONDARY ACCESSION(S): PRJNA91911

REPOSITORIES: GEO

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Thermoprotection in the Drosophila hsf4 mutant

Project description:In Drosophila larvae, acquired synaptic thermotolerance following heat shock has previously been shown to correlate with the induction of heat shock proteins (Hsps) including HSP70. We tested the hypothesis that synaptic thermotolerance would be significantly diminished in a temperature-sensitive strain (hsf4) which has been reported not to be able to produce inducible Hsps in response to heat shock. Contrary to our hypothesis, considerable thermoprotection was still observed at hsf4 larval synapses following heat shock. To investigate the cause of this thermoprotection, we conducted DNA microarray experiments to identify heat-induced transcript changes in these organisms. Transcripts of the hsp83, dnaJ-1(hsp40) and gstE1 genes were significantly up-regulated in hsf4 larvae after heat shock. In addition, increases in the levels of Hsp83 and DnaJ-1 proteins but not in the inducible form of Hsp70 were detected by Western blotting. The mode of heat shock administration differentially affected the relative transcript and translational changes for these chaperones. These results indicate that the compensatory up-regulation of constitutively expressed Hsps, in the absence of the synthesis of inducible Hsps including HSP70, could still provide substantial thermoprotection to both synapses and the whole organism. Two strains were used in this study; the mutant cn bw hsf4 strain, and the dp cn bw cl control strain from which the mutant was derived. For each strain, co-reared larvae were separated into a control group and a treatment group at random. RNA from the heat-shocked larvae and from the respective controls were directly compared on cDNA microarrays (GPL311). Two independent biological samples from each genotype were collected. In addition, an inter-strain comparison was made using the RNA from the untreated controls from each genotype. This was also performed in duplicate.

2005-11-30 | E-GEOD-2998 | biostudies-arrayexpress

Gene expression analysis during heat shock in Drosophila melanogaster 3rd instar hsf4 cn bw larvae

Project description:Gene expression analysis of Drosophila melanogaster 3rd instar hsf4 cn bw larvae, under heat shock and non-heat shock conditions (room temperature) using Nimblegen arrrays (GPL8443)

2011-01-05 | GSE22332 | GEO

Assessment of Thermotolerance in preshocked hsp70(-/-) and (+/+) cells

Project description:From preliminary experiments, HSP70 deficient MEF cells display moderate thermotolerance to a severe heatshock of 45.5 degrees after a mild preshock at 43 degrees, even in the absence of hsp70 protein. We would like to determine which genes in these cells are being activated to account for this thermotolerance. Keywords: thermal stress, heat shock response, knockout, cell culture, hsp70

2009-04-09 | GSE11120 | GEO

Regulation and physiological function of proteins for heat tolerance in cowpea (Vigna unguiculata) genotypes under controlled and field conditions

Project description:The expression of heat shock proteins is considered a central adaptive mechanism to heat stress. This study investigated the expression of heat shock proteins (HSPs) and other stress-protective proteins against heat stress in cowpea genotypes under field (IT-96D-610 and IT-16) and controlled (IT-96D-610) conditions. Plants in the control environment were under 25/20°C (day/night) in a warm chamber and 40/25 °C in a hot chamber. In the field, plants grew at Eensaamheid with 26 to 28°C and at Marapyane with 30 to 32°C monthly average maximum temperatures. Heat stress response analysis of proteins at 72 h in the controlled environment showed 270 differentially regulated proteins identified using label-free quantitative proteomics in IT-96D-610 plants. These plants expressed HSPs and chaperones (BAG family molecular chaperone 6 (BAG6), Multiprotein bridging factor1c (MBF1C) and cold shock domain protein 1 (CSDP1)) in the controlled environment. However, IT-96D-610 plants expressed a wider variety of small HSPs and more HSPs in the field. IT-96D-610 plants also responded to heat stress by exclusively expressing chaperones (DnaJ chaperones, universal stress protein and heat shock binding protein (HSBP)) and non-HSP proteins (Deg1, EGY3, ROS protective proteins, temperature-induced lipocalin and succinic dehydrogenase). Photosynthesis recovery and induction of proteins related to photosynthesis, were better in IT-96D-610 because of the concurrent induction of heat stress response proteins for chaperone functions, protein degradation for repair and ROS scavenging proteins and PSII operating efficiency (Fq’/Fm’) than IT-16. This study contributes to identification of thermotolerance mechanisms in cowpea that can be useful in knowledge-based crop improvement.

2022-08-08 | PXD035418 | Pride

Rapid acetylation of yeast Hsp70 mediates the cellular response to heat stress

Project description:Hsp70 is a highly conserved molecular chaperone critical for the folding of new and denatured proteins. While traditional models state that cells respond to stress by upregulating inducible HSPs, this response is relatively slow and is limited by transcriptional and translational machinery. Recent studies have identified a number of post-translational modifications (PTMs) on Hsp70 that act to fine-tune its function. We utilized mass spectrometry to determine whether yeast Hsp70 (Ssa1) is differentially modified upon heat shock. We uncovered four lysine residues on Ssa1, K86, K185, K354 and K562 that are deacetylated in response to heat shock. Mutation of these sites cause a substantial remodeling of the Hsp70 interaction network of co-chaperone partners and client proteins while preserving essential chaperone function. Acetylation/deacetylation at these residues alter expression of other heat-shock induced chaperones as well as directly influencing Hsf1 activity. Taken together our data suggest that cells may have the ability to respond to heat stress quickly though Hsp70 deacetylation, followed by a slower, more traditional transcriptional response.

2020-02-24 | PXD015185 | Pride

Impaired stability of tumor cells after targeting of lactate/pyruvate metabolism investigated by shotgun proteomics

Project description:Overexpression of heat shock proteins (HSPs), especially the major stress-inducible 72 kDa heat shock protein 70 (Hsp70), in malignant tumor cells is associated with therapeutic resistance. The heightened metabolic demand in tumor cells (Warburg effect) increases lactate dehydrogenase (LDH) activity and the corresponding increase in lactate concentrations promotes malignancy. Herein, we assessed the co-regulation of LDH and the heat shock response and its link to radiation resistance in B16F10 murine melanoma cells and LS174T human colorectal adenocarcinoma cells. Inhibition of LDHA/B by oxamate or GNE-140, significantly diminishes the expression of Hsp90, Hsp70 and Hsp27 in the cytosol. Diminished expression was also observed in LDHA/B double knockout (LDH-/-) cells. An increased production of reactive oxygen species (ROS) induced by a faster growth rate in wild type (WT) vs LDH-/- cells contributes to increased cytosolic HSP levels in WT cells. LDH-/- cells exhibit a lower density of membrane Hsp70 expression than WT cells and a decreased presence of the tumor-specific, Hsp70 anchoring glycosphingolipid Gb3 on the cell surface which could be attributed to an altered lipid metabolism mediated by the LDH knockout. Functionally, a double knockout of LDHA/B results in a generalized reduction in expression of HSPs in tumor cells and significantly increases radiosensitivity which is associated with a G2/M arrest. In summary, we demonstrate that pharmacological targeting of the lactate/pyruvate metabolism breaks radioresistance by impairing the stress response.

2022-02-17 | PXD026078 | Pride

Heat shock response in Arabidopsis Hsa32 knockout mutant

Project description:Plants and animals share similar mechanisms in the heat-shock (HS) response, such as synthesis of the conserved HS proteins (Hsps). However, because plants are confined to a growing environment, in general they require unique features to cope with heat stress. We have analyzed the function of a novel Hsp, heat-stress-associated 32-kD protein (Hsa32), which is highly conserved in land plants but absent in most other organisms. The gene responds to HS at the transcriptional level in moss, Arabidopsis, and rice. Like other Hsps, Hsa32 protein accumulates greatly in Arabidopsis seedlings after HS treatment. Disruption of Hsa32 by T-DNA insertion does not affect growth and development under normal conditions. However, the acquired thermotolerance in the knockout line was compromised following a long recovery period (> 24 h) after an acclimation HS treatment, when a severe HS challenge killed the mutant but not the wild-type plants, but no significant difference was observed if they were challenged within a short recovery period. Microarray analysis of the knockout mutant indicates that only the expression of Hsa32 was significantly altered in HS response. Taken together, our results suggest that Hsa32 is not required for the induction but maintenance of acquired thermotolerance. This report provides direct evidence that a plant-specific Hsp plays an important role in thermotolerance. Keywords: heat shock response

2006-03-20 | GSE4062 | GEO

Sivery2016 - A mammalian heat shock response model

Project description:Environmental stress, such as oxidative or heat stress, induces the activation of the heat shock response (HSR) and leads to an increase in the heat shock proteins (HSPs) level. These HSPs act as molecular chaperones to maintain cellular proteostasis. Controlled by highly intricate regulatory mechanisms, having stress-induced activation and feedback regulations with multiple partners, the HSR is still incompletely understood. In this context, we propose a minimal molecular model for the gene regulatory network of the HSR that reproduces quantitatively different heat shock experiments both on heat shock factor 1 (HSF1) and HSPs activities. This model, which is based on chemical kinetics laws, is kept with a low dimensionality without altering the biological interpretation of the model dynamics. This simplistic model highlights the titration of HSF1 by chaperones as the guiding line of the network. Moreover, by a steady states analysis of the network, three different temperature stress regimes appear: normal, acute, and chronic, where normal stress corresponds to pseudo thermal adaption. The protein triage that governs the fate of damaged proteins or the different stress regimes are consequences of the titration mechanism. The simplicity of the present model is of interest in order to study detailed modelling of cross regulation between the HSR and other major genetic networks like the cell cycle or the circadian clock. Sivéry, A., Courtade, E., Thommen, Q. (2016). A minimal titration model of the mammalian dynamical heat shock response. Physical biology, 13(6), 066008.

2022-01-25 | MODEL2201210001 | BioModels

Dissecting the yeast heat shock response by CRISPRi/a

Project description:CRISPRi screens on the repression of 129 protein kinases and 161 transcription factors in S. cerevisiae. We quantify perturbation effects on cellular fitness at 23, 30 and 38°C, expression of the SSA1 Hsp70 chaperone (as proxy for heat shock response activity) and thermotolerance. The integration of these phenotypes allowed us to identify core signaling pathways of the HSR and their contributions to temperature-associated growth and heat resistance.

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Transcription profiling of Arabidopsis Hsa32 mutant and wild type plants subjected to heat shock

2007-06-27 | E-GEOD-4062 | biostudies-arrayexpress

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