scholarly journals Large Organellar Changes Occur during Mild Heat Shock in Yeast

2021 ◽  
Author(s):  
Katharina Keuenhof ◽  
Lisa Larsson Berglund ◽  
Sandra Malmgren Hill ◽  
Kara L Schneider ◽  
Per O Widlund ◽  
...  
Keyword(s):  
Heat Shock ◽  
Heat Shock Response ◽  
Time Course ◽  
Cellular Stress Response ◽  
Mild Heat ◽  
Cellular Environment ◽  
Shock Response ◽  
Summary Statement ◽  
Novel Structures ◽  
Continuous Heat

AbstractWhen the temperature is increased, the heat shock response is activated to protect the cellular environment. The transcriptomics and proteomics of this process are intensively studied, while information about how the cell responds structurally to heat stress is mostly lacking. Here, Saccharomyces cerevisiae were subjected to a mild continuous heat shock and intermittently cryo-immobilized for electron microscopy. Through measuring changes in all distinguishable organelle numbers, sizes, and morphologies in over 2400 electron micrographs a major restructuring of the cell’s internal architecture during the progressive heat shock was revealed. The cell grew larger but most organelles within it expanded even more. Organelles responded to heat shock at different times, both in terms of size and number, and adaptations of certain organelles’ morphology were observed. Multivesicular bodies grew to almost 170% in size, indicating a previously unknown involvement in the heat shock response. A previously undescribed electron translucent structure accumulated close to the plasma membrane during the entire time course. This all-encompassing approach provides a detailed chronological progression of organelle adaptation throughout the cellular stress response.Summary statementExposure to mild heat shock leads to large quantifiable changes in the cellular ultrastructure of yeast, shows involvement of MVBs in the heat shock response and the apparition of novel structures.

scholarly journals Large organellar changes occur during mild heat shock in yeast

2021 ◽  
Author(s):  
Katharina S Keuenhof ◽  
Lisa Larsson Berglund ◽  
Sandra Malmgren Hill ◽  
Kara L Schneider ◽  
Per O Widlund ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Heat Stress ◽  
Heat Shock ◽  
Heat Shock Response ◽  
Multivesicular Bodies ◽  
Heat Stress Response ◽  
Cellular Environment ◽  
Shock Response ◽  
Continuous Heat ◽  
Internal Architecture

When the temperature is increased, the heat shock response is activated to protect the cellular environment. The transcriptomics and proteomics of this process are intensively studied, while information about how the cell responds structurally to heat stress is mostly lacking. Here, Saccharomyces cerevisiae were subjected to a mild continuous heat shock (38°C) and intermittently cryo-immobilized for electron microscopy. Through measuring changes in all distinguishable organelle numbers, sizes, and morphologies in over 2100 electron micrographs a major restructuring of the cell's internal architecture during the progressive heat shock was revealed. The cell grew larger but most organelles within it expanded even more, shrinking the volume of the cytoplasm. Organelles responded to heat shock at different times, both in terms of size and number, and adaptations of certain organelles’ morphology (such as the vacuole), were observed. Multivesicular bodies grew to almost 170% in size, indicating a previously unknown involvement in the heat shock response. A previously undescribed electron translucent structure accumulated close to the plasma membrane. This all-encompassing approach provides a detailed chronological progression of organelle adaptation throughout the cellular heat-stress response.

scholarly journals Global Gene Expression Analysis of the Heat Shock Response in the Phytopathogen Xylella fastidiosa

2006 ◽  
Vol 188 (16) ◽  
pp. 5821-5830 ◽  
Author(s):  
Tie Koide ◽  
Ricardo Z. N. Vêncio ◽  
Suely L. Gomes
Keyword(s):  
Heat Shock ◽  
Stress Responses ◽  
Heat Shock Response ◽  
Time Course ◽  
Protein Biosynthesis ◽  
Xylella Fastidiosa ◽  
Expression Profiles ◽  
Expression Patterns ◽  
Phytopathogenic Bacterium ◽  
Shock Response

ABSTRACT Xylella fastidiosa is a phytopathogenic bacterium that is responsible for diseases in many economically important crops. Although different strains have been studied, little is known about X. fastidiosa stress responses. One of the better characterized stress responses in bacteria is the heat shock response, which induces the expression of specific genes to prevent protein misfolding and aggregation and to promote degradation of the irreversibly denatured polypeptides. To investigate X. fastidiosa genes involved in the heat shock response, we performed a whole-genome microarray analysis in a time course experiment. Globally, 261 genes were induced (9.7%) and 222 genes were repressed (8.3%). The expression profiles of the differentially expressed genes were grouped, and their expression patterns were validated by quantitative reverse transcription-PCR experiments. We determined the transcription start sites of six heat shock-inducible genes and analyzed their promoter regions, which allowed us to propose a putative consensus for σ32 promoters in Xylella and to suggest additional genes as putative members of this regulon. Besides the induction of classical heat shock protein genes, we observed the up-regulation of virulence-associated genes such as vapD and of genes for hemagglutinins, hemolysin, and xylan-degrading enzymes, which may indicate the importance of heat stress to bacterial pathogenesis. In addition, we observed the repression of genes related to fimbriae, aerobic respiration, and protein biosynthesis and the induction of genes related to the extracytoplasmic stress response and some phage-related genes, revealing the complex network of genes that work together in response to heat shock.

scholarly journals Urocortin 3 overexpression reduces ER stress and heat shock response in 3T3-L1 adipocytes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sina Kavalakatt ◽  
Abdelkrim Khadir ◽  
Dhanya Madhu ◽  
Heikki A. Koistinen ◽  
Fahd Al-Mulla ◽  
...  
Keyword(s):  
Stress Response ◽  
Heat Shock ◽  
Er Stress ◽  
Glucose Uptake ◽  
Heat Shock Response ◽  
Cellular Stress Response ◽  
Mrna Levels ◽  
Obesity And Diabetes ◽  
Shock Response ◽  
Urocortin 3

AbstractThe neuropeptide urocortin 3 (UCN3) has a beneficial effect on metabolic disorders, such as obesity, diabetes, and cardiovascular disease. It has been reported that UCN3 regulates insulin secretion and is dysregulated with increasing severity of obesity and diabetes. However, its function in the adipose tissue is unclear. We investigated the overexpression of UCN3 in 3T3-L1 preadipocytes and differentiated adipocytes and its effects on heat shock response, ER stress, inflammatory markers, and glucose uptake in the presence of stress-inducing concentrations of palmitic acid (PA). UCN3 overexpression significantly downregulated heat shock proteins (HSP60, HSP72 and HSP90) and ER stress response markers (GRP78, PERK, ATF6, and IRE1α) and attenuated inflammation (TNFα) and apoptosis (CHOP). Moreover, enhanced glucose uptake was observed in both preadipocytes and mature adipocytes, which is associated with upregulated phosphorylation of AKT and ERK but reduced p-JNK. Moderate effects of UCN3 overexpression were also observed in the presence of 400 μM of PA, and macrophage conditioned medium dramatically decreased the UCN3 mRNA levels in differentiated 3T3-L1 cells. In conclusion, the beneficial effects of UCN3 in adipocytes are reflected, at least partially, by the improvement in cellular stress response and glucose uptake and attenuation of inflammation and apoptosis.

scholarly journals Quantitative proteomics identifies the universally conserved ATPase Ola1p as a positive regulator of heat shock response in Saccharomyces cerevisiae

2021 ◽  
Author(s):  
Stefan Dannenmaier ◽  
Christine Desroches Altamirano ◽  
Lisa Schueler ◽  
Ying Zhang ◽  
Johannes Hummel ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Heat Stress ◽  
Heat Shock ◽  
Heat Shock Response ◽  
De Novo ◽  
Stress Granules ◽  
Cellular Stress Response ◽  
Protein Ubiquitination ◽  
Shock Response

The universally conserved P-loop ATPase Ola1 is implicated in various cellular stress response pathways, as well as in cancer and tumor progression. However, Ola1p functions are divergent between species and the involved mechanisms are only poorly understood. Here, we studied the role of Ola1p in the heat shock response of the yeast Saccharomyces cerevisiae using a combination of quantitative and pulse labeling-based proteomics approaches, in vitro studies and cell-based assays. Our data show that when heat stress is applied to cells lacking Ola1p, the expression of stress-protective proteins is enhanced. During heat stress Ola1p associates with detergent-resistant protein aggregates and rapidly forms assemblies that localize to stress granules. The assembly of Ola1p was also observed in vitro using purified protein and conditions, which resembled those in living cells. We show that loss of Ola1p results in increased protein ubiquitination of detergent-insoluble aggregates recovered from heat-shocked cells. When subsequently cells lacking Ola1p were relieved from heat stress, reinitiation of translation was delayed, whereas, at the same time, de novo synthesis of central factors required for protein refolding and the clearance of aggregates was enhanced when compared to wildtype cells. The combined data suggest that upon acute heat stress, Ola1p is involved in the stabilization of misfolded proteins, which become sequestered in cytoplasmic stress granules. This function of Ola1p enables cells to resume translation in a timely manner as soon as heat stress is relieved.

scholarly journals ReporterSeq reveals genome-wide dynamic modulators of the heat shock response across diverse stressors

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Brian D Alford ◽  
Eduardo Tassoni-Tsuchida ◽  
Danish Khan ◽  
Jeremy J Work ◽  
Gregory Valiant ◽  
...  
Keyword(s):  
Heat Shock ◽  
Heat Shock Response ◽  
Cellular Stress Response ◽  
Response Dynamics ◽  
Time Resolved ◽  
Genetic Method ◽  
Genome Wide ◽  
Activity Measurements ◽  
Shock Response ◽  
Time Specific

Understanding cellular stress response pathways is challenging because of the complexity of regulatory mechanisms and response dynamics, which can vary with both time and the type of stress. We developed a reverse genetic method called ReporterSeq to comprehensively identify genes regulating a stress-induced transcription factor under multiple conditions in a time-resolved manner. ReporterSeq links RNA-encoded barcode levels to pathway-specific output under genetic perturbations, allowing pooled pathway activity measurements via DNA sequencing alone and without cell enrichment or single-cell isolation. We used ReporterSeq to identify regulators of the heat shock response (HSR), a conserved, poorly understood transcriptional program that protects cells from proteotoxicity and is misregulated in disease. Genome-wide HSR regulation in budding yeast was assessed across 15 stress conditions, uncovering novel stress-specific, time-specific, and constitutive regulators. ReporterSeq can assess the genetic regulators of any transcriptional pathway with the scale of pooled genetic screens and the precision of pathway-specific readouts.

scholarly journals Genome-wide, time-sensitive interrogation of the heat shock response under diverse stressors via ReporterSeq

2020 ◽  
Author(s):  
Brian D. Alford ◽  
Gregory Valiant ◽  
Onn Brandman
Keyword(s):  
Heat Shock ◽  
Heat Shock Response ◽  
Cellular Stress Response ◽  
Response Dynamics ◽  
Time Resolved ◽  
Genetic Method ◽  
Genome Wide ◽  
Activity Measurements ◽  
Shock Response ◽  
Time Specific

AbstractInterrogating cellular stress response pathways is challenging because of the complexity of regulatory mechanisms and response dynamics, which can vary with both time and the type of stress. We developed a reverse genetic method called ReporterSeq to comprehensively identify genes regulating a stress-induced transcription factor under multiple conditions in a time-resolved manner. ReporterSeq links RNA-encoded barcode levels to pathway-specific output under genetic perturbations, allowing pooled pathway activity measurements via DNA sequencing alone and without cell enrichment or single cell isolation. Here, we used ReporterSeq to identify regulators of the heat shock response (HSR), a conserved, poorly understood transcriptional program that protects cells from proteotoxicity and is misregulated in disease. We measured genome-wide HSR regulation in budding yeast across thirteen stress conditions, uncovering novel stress-specific, time-specific, and constitutive regulators. ReporterSeq can assess the genetic regulators of any transcriptional pathway with the scale of pooled genetic screens and the precision of pathway-specific readouts.

scholarly journals Efficient Heat Shock Response Affects Hyperthermia-Induced Radiosensitization in a Tumor Spheroid Control Probability Assay

Cancers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 3168
Author(s):  
Oleg Chen ◽  
Soňa Michlíková ◽  
Lisa Eckhardt ◽  
Marit Wondrak ◽  
Adriana M. De Mendoza ◽  
...  
Keyword(s):  
Stress Response ◽  
Heat Shock ◽  
Heat Shock Response ◽  
Cellular Stress Response ◽  
Proteotoxic Stress ◽  
Shock Response ◽  
Pre Treatment ◽  
Shock Proteins ◽  
The Impact

Hyperthermia (HT) combined with irradiation is a well-known concept to improve the curative potential of radiotherapy. Technological progress has opened new avenues for thermoradiotherapy, even for recurrent head and neck squamous cell carcinomas (HNSCC). Preclinical evaluation of the curative radiosensitizing potential of various HT regimens remains ethically, economically, and technically challenging. One key objective of our study was to refine an advanced 3-D assay setup for HT + RT research and treatment testing. For the first time, HT-induced radiosensitization was systematically examined in two differently radioresponsive HNSCC spheroid models using the unique in vitro “curative” analytical endpoint of spheroid control probability. We further investigated the cellular stress response mechanisms underlying the HT-related radiosensitization process with the aim to unravel the impact of HT-induced proteotoxic stress on the overall radioresponse. HT disrupted the proteome’s thermal stability, causing severe proteotoxic stress. It strongly enhanced radiation efficacy and affected paramount survival and stress response signaling networks. Transcriptomics, q-PCR, and western blotting data revealed that HT + RT co-treatment critically triggers the heat shock response (HSR). Pre-treatment with chemical chaperones intensified the radiosensitizing effect, thereby suppressing HT-induced Hsp27 expression. Our data suggest that HT-induced radiosensitization is adversely affected by the proteotoxic stress response. Hence, we propose the inhibition of particular heat shock proteins as a targeting strategy to improve the outcome of combinatorial HT + RT.

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