Yeast stress granules at a glance

ABSTRACT The eukaryotic cytosol contains multiple RNP granules, including P-bodies and stress granules. Three different methods have been used to describe the transcriptome of stress granules or P-bodies, but how these methods compare and how RNA partitioning occurs between P-bodies and stress granules have not been addressed. Here, we compare the analysis of the stress granule transcriptome based on differential centrifugation with and without subsequent stress granule immunopurification. We find that while differential centrifugation alone gives a first approximation of the stress granule transcriptome, this methodology contains nonspecific transcripts that play a confounding role in the interpretation of results. We also immunopurify and compare the RNAs in stress granules and P-bodies under arsenite stress and compare those results to those for the P-body transcriptome described under nonstress conditions. We find that the P-body transcriptome is dominated by poorly translated mRNAs under nonstress conditions, but during arsenite stress, when translation is globally repressed, the P-body transcriptome is very similar to the stress granule transcriptome. This suggests that translation is a dominant factor in targeting mRNAs into both P-bodies and stress granules, and during stress, when most mRNAs are untranslated, the composition of P-bodies reflects this broader translation repression.

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Puumala and Andes Orthohantaviruses Cause Transient Protein Kinase R-Dependent Formation of Stress Granules

Journal of Virology ◽

10.1128/jvi.01168-19 ◽

2019 ◽

Vol 94 (3) ◽

Cited By ~ 4

Author(s):

Wanda Christ ◽

Janne Tynell ◽

Jonas Klingström

Keyword(s):

Protein Kinase ◽

Host Cell ◽

Stress Responses ◽

Stress Granules ◽

Cell Stress ◽

Stress Granule ◽

Hantavirus Infection ◽

Stress Signaling ◽

Protein Kinase R ◽

Granule Formation

ABSTRACT Virus infection frequently triggers host cell stress signaling resulting in translational arrest; as a consequence, many viruses employ means to modulate the host stress response. Hantaviruses are negative-sense, single-stranded RNA viruses known to inhibit host innate immune responses and apoptosis, but their impact on host cell stress signaling remains largely unknown. In this study, we investigated activation of host cell stress responses during hantavirus infection. We show that hantavirus infection causes transient formation of stress granules (SGs) but does so in only a limited proportion of infected cells. Our data indicate some cell type-specific and hantavirus species-specific variability in SG prevalence and show SG formation to be dependent on the activation of protein kinase R (PKR). Hantavirus infection inhibited PKR-dependent SG formation, which could account for the transient nature and low prevalence of SG formation observed during hantavirus infection. In addition, we report only limited colocalization of hantaviral proteins or RNA with SGs and show evidence indicating hantavirus-mediated inhibition of PKR-like endoplasmic reticulum (ER) kinase (PERK). IMPORTANCE Our work presents the first report on stress granule formation during hantavirus infection. We show that hantavirus infection actively inhibits stress granule formation, thereby escaping the detrimental effects on global translation imposed by host stress signaling. Our results highlight a previously uncharacterized aspect of hantavirus-host interactions with possible implications for how hantaviruses are able to cause persistent infection in natural hosts and for pathogenesis.

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Detecting and quantifying stress granules in tissues of multicellular organisms with the Obj.MPP analysis tool

Traffic ◽

10.1111/tra.12678 ◽

2019 ◽

Cited By ~ 1

Author(s):

Fabienne De Graeve ◽

Eric Debreuve ◽

Somia Rahmoun ◽

Szilvia Ecsedi ◽

Alia Bahri ◽

...

Keyword(s):

Stress Granules ◽

Analysis Tool ◽

Multicellular Organisms

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

Molecular and Cellular Biology ◽

10.1128/mcb.23.8.2953-2968.2003 ◽

2003 ◽

Vol 23 (8) ◽

pp. 2953-2968 ◽

Cited By ~ 205

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.

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Stress granules and Plasmodium liver stage infection

Biology Open ◽

10.1242/bio.20136833 ◽

2013 ◽

Vol 3 (1) ◽

pp. 103-107 ◽

Cited By ~ 6

Author(s):

K. K. Hanson ◽

G. R. Mair

Keyword(s):

Stress Granules ◽

Liver Stage ◽

Stage Infection

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Translationally Repressed mRNA Transiently Cycles through Stress Granules during Stress

Molecular Biology of the Cell ◽

10.1091/mbc.e08-05-0499 ◽

2008 ◽

Vol 19 (10) ◽

pp. 4469-4479 ◽

Cited By ~ 124

Author(s):

Stephanie Mollet ◽

Nicolas Cougot ◽

Ania Wilczynska ◽

François Dautry ◽

Michel Kress ◽

...

Keyword(s):

Residence Time ◽

Kinetic Data ◽

Stress Granules ◽

Stress Relief ◽

Mrna Degradation ◽

Stress Granule ◽

Storage Site ◽

Direct Role ◽

Close Proximity

In mammals, repression of translation during stress is associated with the assembly of stress granules in the cytoplasm, which contain a fraction of arrested mRNA and have been proposed to play a role in their storage. Because physical contacts are seen with GW bodies, which contain the mRNA degradation machinery, stress granules could also target arrested mRNA to degradation. Here we show that contacts between stress granules and GW bodies appear during stress-granule assembly and not after a movement of the two preassembled structures. Despite this close proximity, the GW body proteins, which in some conditions relocalize in stress granules, come from cytosol rather than from adjacent GW bodies. It was previously reported that several proteins actively traffic in and out of stress granules. Here we investigated the behavior of mRNAs. Their residence time in stress granules is brief, on the order of a minute, although stress granules persist over a few hours after stress relief. This short transit reflects rapid return to cytosol, rather than transfer to GW bodies for degradation. Accordingly, most arrested mRNAs are located outside stress granules. Overall, these kinetic data do not support a direct role of stress granules neither as storage site nor as intermediate location before degradation.

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