scholarly journals Heat shock causes a decrease in polysomes and the appearance of stress granules in trypanosomes independently of eIF2  phosphorylation at Thr169

2008 ◽  
Vol 121 (18) ◽  
pp. 3002-3014 ◽  
Author(s):  
S. Kramer ◽  
R. Queiroz ◽  
L. Ellis ◽  
H. Webb ◽  
J. D. Hoheisel ◽  
...  
Keyword(s):  
Heat Shock ◽  
Stress Granules ◽  
Eif2 Phosphorylation

scholarly journals Phosphorylation of Serine 303 Is a Prerequisite for the Stress-Inducible SUMO Modification of Heat Shock Factor 1

2003 ◽  
Vol 23 (8) ◽  
pp. 2953-2968 ◽  
Author(s):  
Ville Hietakangas ◽  
Johanna K. Ahlskog ◽  
Annika M. Jakobsson ◽  
Maria Hellesuo ◽  
Niko M. Sahlberg ◽  
...  
Keyword(s):  
Heat Shock ◽  
Phosphorylation Site ◽  
Stress Granules ◽  
Heat Shock Factor ◽  
Transcriptional Level ◽  
Heat Shock Factor 1 ◽  
Protection Mechanism ◽  
Sumo Modification

ABSTRACT The heat shock response, which is accompanied by a rapid and robust upregulation of heat shock proteins (Hsps), is a highly conserved protection mechanism against protein-damaging stress. Hsp induction is mainly regulated at transcriptional level by stress-inducible heat shock factor 1 (HSF1). Upon activation, HSF1 trimerizes, binds to DNA, concentrates in the nuclear stress granules, and undergoes a marked multisite phosphorylation, which correlates with its transcriptional activity. In this study, we show that HSF1 is modified by SUMO-1 and SUMO-2 in a stress-inducible manner. Sumoylation is rapidly and transiently enhanced on lysine 298, located in the regulatory domain of HSF1, adjacent to several critical phosphorylation sites. Sumoylation analyses of HSF1 phosphorylation site mutants reveal that specifically the phosphorylation-deficient S303 mutant remains devoid of SUMO modification in vivo and the mutant mimicking phosphorylation of S303 promotes HSF1 sumoylation in vitro, indicating that S303 phosphorylation is required for K298 sumoylation. This finding is further supported by phosphopeptide mapping and analysis with S303/7 phosphospecific antibodies, which demonstrate that serine 303 is a target for strong heat-inducible phosphorylation, corresponding to the inducible HSF1 sumoylation. A transient phosphorylation-dependent colocalization of HSF1 and SUMO-1 in nuclear stress granules provides evidence for a strictly regulated subnuclear interplay between HSF1 and SUMO.

scholarly journals Immunomodulation of function of small heat shock proteins prevents their assembly into heat stress granules and results in cell death at sublethal temperatures

2004 ◽  
Vol 41 (2) ◽  
pp. 269-281 ◽  
Author(s):  
Sergey Miroshnichenko ◽  
Joanna Tripp ◽  
Uta zur Nieden ◽  
Dieter Neumann ◽  
Udo Conrad ◽  
...  
Keyword(s):  
Cell Death ◽  
Heat Stress ◽  
Heat Shock ◽  
Heat Shock Proteins ◽  
Stress Granules ◽  
Small Heat Shock Proteins ◽  
Shock Proteins

scholarly journals Stable Formation of Compositionally Unique Stress Granules in Virus-Infected Cells

2009 ◽  
Vol 84 (7) ◽  
pp. 3654-3665 ◽  
Author(s):  
Joanna Piotrowska ◽  
Spencer J. Hansen ◽  
Nogi Park ◽  
Katarzyna Jamka ◽  
Peter Sarnow ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Heat Shock ◽  
Viral Infections ◽  
De Novo ◽  
Stress Granules ◽  
Stress Granule ◽  
Initiation Factor ◽  
Granule Formation ◽  
Infected Cells ◽  
Positive Strand Rna

ABSTRACT Stress granules are sites of mRNA storage formed in response to a variety of stresses, including viral infections. Here, the mechanisms and consequences of stress granule formation during poliovirus infection were examined. The results indicate that stress granules containing T-cell-restricted intracellular antigen 1 (TIA-1) and mRNA are stably constituted in infected cells despite lacking intact RasGAP SH3-domain binding protein 1 (G3BP) and eukaryotic initiation factor 4G. Fluorescent in situ hybridization revealed that stress granules in infected cells do not contain significant amounts of viral positive-strand RNA. Infection does not prevent stress granule formation in response to heat shock, indicating that poliovirus does not block de novo stress granule formation. A mutant TIA-1 protein that prevents stress granule formation during oxidative stress also prevents formation in infected cells. However, stress granule formation during infection is more dependent upon ongoing transcription than is formation during oxidative stress or heat shock. Furthermore, Sam68 is recruited to stress granules in infected cells but not to stress granules formed in response to oxidative stress or heat shock. These results demonstrate that stress granule formation in poliovirus-infected cells utilizes a transcription-dependent pathway that results in the appearance of stable, compositionally unique stress granules.

scholarly journals Nuclear stress granules

2004 ◽  
Vol 164 (1) ◽  
pp. 15-17 ◽  
Author(s):  
Anton Sandqvist ◽  
Lea Sistonen
Keyword(s):  
Heat Shock ◽  
Transcriptional Activation ◽  
Heterochromatic Region ◽  
Stress Granules ◽  
Mrna Processing ◽  
Stress Granule ◽  
Target Sites ◽  
Processing Factors

Nuclear stress granules are subnuclear compartments that form in response to heat shock and other stress stimuli. Although many components of nuclear stress granules have been identified, including HSF1 and pre-mRNA processing factors, their function remains a mystery. A paper in this issue describes the stress-induced transcriptional activation of one of the nuclear stress granule target sites, a heterochromatic region that has been considered silent (Jolly et al., 2004). These intriguing findings will certainly give the research of these structures a new twist.

scholarly journals Stress-induced transcription of satellite III repeats

2003 ◽  
Vol 164 (1) ◽  
pp. 25-33 ◽  
Author(s):  
Caroline Jolly ◽  
Alexandra Metz ◽  
Jérôme Govin ◽  
Marc Vigneron ◽  
Bryan M. Turner ◽  
...  
Keyword(s):  
Heat Shock ◽  
Rna Polymerase Ii ◽  
Mammalian Cells ◽  
Stress Granules ◽  
Transcription Sites ◽  
Direct Binding ◽  
Nuclear Structures ◽  
Hsp Genes ◽  
Transcription Factor 1 ◽  
Rna Polymerase Ii Transcription

Exposure of mammalian cells to stress induces the activation of heat shock transcription factor 1 (HSF1) and the subsequent transcription of heat shock genes. Activation of the heat shock response also correlates with a rapid relocalization of HSF1 within a few nuclear structures termed nuclear stress granules. These stress-induced structures, which form primarily on the 9q12 region in humans through direct binding of HSF1 to satellite III repeats, do not colocalize with transcription sites of known hsp genes. In this paper, we show that nuclear stress granules correspond to RNA polymerase II transcription factories where satellite III repeats are transcribed into large and stable RNAs that remain associated with the 9q12 region, even throughout mitosis. This work not only reveals the existence of a new major heat-induced transcript in human cells that may play a role in chromatin structure, but also provides evidence for a transcriptional activity within a locus considered so far as heterochromatic and silent.

scholarly journals Heat Shock-Induced Accumulation of Translation Elongation and Termination Factors Precedes Assembly of Stress Granules in S. cerevisiae

PLoS ONE ◽  
2013 ◽  
Vol 8 (2) ◽  
pp. e57083 ◽  
Author(s):  
Tomas Grousl ◽  
Pavel Ivanov ◽  
Ivana Malcova ◽  
Petr Pompach ◽  
Ivana Frydlova ◽  
...  
Keyword(s):  
Heat Shock ◽  
Stress Granules ◽  
Translation Elongation

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.

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