scholarly journals Stress granules, RNA-binding proteins and polyglutamine diseases: too much aggregation?

2021 ◽  
Vol 12 (6) ◽  
Author(s):  
Adriana Marcelo ◽  
Rebekah Koppenol ◽  
Luís Pereira de Almeida ◽  
Carlos A. Matos ◽  
Clévio Nóbrega
Keyword(s):  
Self Assembly ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Cell Signalling ◽  
Stress Granules ◽  
Polyq Disease ◽  
Cell Compartments ◽  
Polyq Diseases ◽  
Polyq Tract

AbstractStress granules (SGs) are membraneless cell compartments formed in response to different stress stimuli, wherein translation factors, mRNAs, RNA-binding proteins (RBPs) and other proteins coalesce together. SGs assembly is crucial for cell survival, since SGs are implicated in the regulation of translation, mRNA storage and stabilization and cell signalling, during stress. One defining feature of SGs is their dynamism, as they are quickly assembled upon stress and then rapidly dispersed after the stress source is no longer present. Recently, SGs dynamics, their components and their functions have begun to be studied in the context of human diseases. Interestingly, the regulated protein self-assembly that mediates SG formation contrasts with the pathological protein aggregation that is a feature of several neurodegenerative diseases. In particular, aberrant protein coalescence is a key feature of polyglutamine (PolyQ) diseases, a group of nine disorders that are caused by an abnormal expansion of PolyQ tract-bearing proteins, which increases the propensity of those proteins to aggregate. Available data concerning the abnormal properties of the mutant PolyQ disease-causing proteins and their involvement in stress response dysregulation strongly suggests an important role for SGs in the pathogenesis of PolyQ disorders. This review aims at discussing the evidence supporting the existence of a link between SGs functionality and PolyQ disorders, by focusing on the biology of SGs and on the way it can be altered in a PolyQ disease context.

scholarly journals Stress granules as crucibles of ALS pathogenesis

2013 ◽  
Vol 201 (3) ◽  
pp. 361-372 ◽  
Author(s):  
Yun R. Li ◽  
Oliver D. King ◽  
James Shorter ◽  
Aaron D. Gitler
Keyword(s):  
Motor Neurons ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Stress Granules ◽  
Normal Function ◽  
Genes Encoding ◽  
Als Patients ◽  
Lateral Sclerosis ◽  
Human Neurodegenerative Disease

Amyotrophic lateral sclerosis (ALS) is a fatal human neurodegenerative disease affecting primarily motor neurons. Two RNA-binding proteins, TDP-43 and FUS, aggregate in the degenerating motor neurons of ALS patients, and mutations in the genes encoding these proteins cause some forms of ALS. TDP-43 and FUS and several related RNA-binding proteins harbor aggregation-promoting prion-like domains that allow them to rapidly self-associate. This property is critical for the formation and dynamics of cellular ribonucleoprotein granules, the crucibles of RNA metabolism and homeostasis. Recent work connecting TDP-43 and FUS to stress granules has suggested how this cellular pathway, which involves protein aggregation as part of its normal function, might be coopted during disease pathogenesis.

scholarly journals Distinct stages in stress granule assembly and disassembly

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Joshua R Wheeler ◽  
Tyler Matheny ◽  
Saumya Jain ◽  
Robert Abrisch ◽  
Roy Parker
Keyword(s):  
Time Course ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Stress Granules ◽  
Stress Granule ◽  
Early Event ◽  
Intrinsically Disordered

Stress granules are non-membrane bound RNA-protein (RNP) assemblies that form when translation initiation is limited and contain a biphasic structure with stable core structures surrounded by a less concentrated shell. The order of assembly and disassembly of these two structures remains unknown. Time course analysis of granule assembly suggests that core formation is an early event in granule assembly. Stress granule disassembly is also a stepwise process with shell dissipation followed by core clearance. Perturbations that alter liquid-liquid phase separations (LLPS) driven by intrinsically disordered protein regions (IDR) of RNA binding proteins in vitro have the opposite effect on stress granule assembly in vivo. Taken together, these observations argue that stress granules assemble through a multistep process initiated by stable assembly of untranslated mRNPs into core structures, which could provide sufficient high local concentrations to allow for a localized LLPS driven by IDRs on RNA binding proteins.

scholarly journals RNA-Binding Proteins Tia-1 and Tiar Link the Phosphorylation of Eif-2α to the Assembly of Mammalian Stress Granules

1999 ◽  
Vol 147 (7) ◽  
pp. 1431-1442 ◽  
Author(s):  
Nancy L. Kedersha ◽  
Mita Gupta ◽  
Wei Li ◽  
Ira Miller ◽  
Paul Anderson
Keyword(s):  
Environmental Stress ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Rna Binding Protein ◽  
Plant Cells ◽  
Stress Granules ◽  
Binding Domains ◽  
Translational Arrest ◽  
In Cells

In response to environmental stress, the related RNA-binding proteins TIA-1 and TIAR colocalize with poly(A)+ RNA at cytoplasmic foci that resemble the stress granules (SGs) that harbor untranslated mRNAs in heat shocked plant cells (Nover et al. 1989; Nover et al. 1983; Scharf et al. 1998). The accumulation of untranslated mRNA at SGs is reversible in cells that recover from a sublethal stress, but irreversible in cells subjected to a lethal stress. We have found that the assembly of TIA-1/R+ SGs is initiated by the phosphorylation of eIF-2α. A phosphomimetic eIF-2α mutant (S51D) induces the assembly of SGs, whereas a nonphosphorylatable eIF-2α mutant (S51A) prevents the assembly of SGs. The ability of a TIA-1 mutant lacking its RNA-binding domains to function as a transdominant inhibitor of SG formation suggests that this RNA-binding protein acts downstream of the phosphorylation of eIF-2α to promote the sequestration of untranslated mRNAs at SGs. The assembly and disassembly of SGs could regulate the duration of stress- induced translational arrest in cells recovering from environmental stress.

scholarly journals LINE-1 ORF1 Protein Localizes in Stress Granules with Other RNA-Binding Proteins, Including Components of RNA Interference RNA-Induced Silencing Complex

2007 ◽  
Vol 27 (18) ◽  
pp. 6469-6483 ◽  
Author(s):  
John L. Goodier ◽  
Lili Zhang ◽  
Melissa R. Vetter ◽  
Haig H. Kazazian
Keyword(s):  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Binding Protein ◽  
Protein A ◽  
Rna Binding Protein ◽  
Stress Granules ◽  
Plasminogen Activator Inhibitor ◽  
Cellular Damage ◽  
Activator Inhibitor

ABSTRACT LINE-1 retrotransposons constitute one-fifth of human DNA and have helped shape our genome. A full-length L1 encodes a 40-kDa RNA-binding protein (ORF1p) and a 150-kDa protein (ORF2p) with endonuclease and reverse transcriptase activities. ORF1p is distinctive in forming large cytoplasmic foci, which we identified as cytoplasmic stress granules. A phylogenetically conserved central region of the protein is critical for wild-type localization and retrotransposition. Yeast two-hybrid screens revealed several RNA-binding proteins that coimmunoprecipitate with ORF1p and colocalize with ORF1p in foci. Two of these proteins, YB-1 and hnRNPA1, were previously reported in stress granules. We identified additional proteins associated with stress granules, including DNA-binding protein A, 9G8, and plasminogen activator inhibitor RNA-binding protein 1 (PAI-RBP1). PAI-RBP1 is a homolog of VIG, a part of the Drosophila melanogaster RNA-induced silencing complex (RISC). Other RISC components, including Ago2 and FMRP, also colocalize with PAI-RBP1 and ORF1p. We suggest that targeting ORF1p, and possibly the L1 RNP, to stress granules is a mechanism for controlling retrotransposition and its associated genetic and cellular damage.

scholarly journals Single-molecule imaging reveals dynamic biphasic partition of RNA-binding proteins in stress granules

2018 ◽  
Vol 217 (4) ◽  
pp. 1303-1318 ◽  
Author(s):  
Benedikt Niewidok ◽  
Maxim Igaev ◽  
Abel Pereira da Graca ◽  
Andre Strassner ◽  
Christine Lenzen ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Single Molecule ◽  
Mammalian Cells ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Liquid Droplet ◽  
Binding Protein ◽  
Stress Granules

Stress granules (SGs) are cytosolic, nonmembranous RNA–protein complexes. In vitro experiments suggested that they are formed by liquid–liquid phase separation; however, their properties in mammalian cells remain unclear. We analyzed the distribution and dynamics of two paradigmatic RNA-binding proteins (RBPs), Ras GTPase-activating protein SH3-domain–binding protein (G3BP1) and insulin-like growth factor II mRNA-binding protein 1 (IMP1), with single-molecule resolution in living neuronal cells. Both RBPs exhibited different exchange kinetics between SGs. Within SGs, single-molecule localization microscopy revealed distributed hotspots of immobilized G3BP1 and IMP1 that reflect the presence of relatively immobile nanometer-sized nanocores. We demonstrate alternating binding in nanocores and anomalous diffusion in the liquid phase with similar characteristics for both RBPs. Reduction of low-complexity regions in G3BP1 resulted in less detectable mobile molecules in the liquid phase without change in binding in nanocores. The data provide direct support for liquid droplet behavior of SGs in living cells and reveal transient binding of RBPs in nanocores. Our study uncovers a surprising disconnect between SG partitioning and internal diffusion and interactions of RBPs.

scholarly journals Identification of the Junctional Plaque Protein Plakophilin 3 in Cytoplasmic Particles Containing RNA-binding Proteins and the Recruitment of Plakophilins 1 and 3 to Stress Granules

2006 ◽  
Vol 17 (3) ◽  
pp. 1388-1398 ◽  
Author(s):  
Ilse Hofmann ◽  
Marialuisa Casella ◽  
Martina Schnölzer ◽  
Tanja Schlechter ◽  
Herbert Spring ◽  
...  
Keyword(s):  
Binding Proteins ◽  
Stress Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Binding Protein ◽  
Gradient Centrifugation ◽  
Intercellular Junctions ◽  
Stress Granules ◽  
Spectrometric Analysis ◽  
Adhesive Interactions

Recent studies on the subcellular distribution of cytoplasmic plaque proteins of intercellular junctions have revealed that a number of such proteins can also occur in the cyto- and the nucleoplasm. This occurrence in different, and distant locations suggest that some plaque proteins play roles in cytoplasmic and nuclear processes in addition to their involvement in cell–cell adhesive interactions. Plakophilin (PKP) 3, a member of the arm-repeat family of proteins, occurs, in a diversity of cell types, both as an architectural component in plaques of desmosomes and dispersed in cytoplasmic particles. In immuno-selection experiments using PKP3-specific antibodies, we have identified by mass spectrometric analysis the following RNA-binding proteins: Poly (A) binding protein (PABPC1), fragile-X-related protein (FXR1), and ras-GAP-SH3-binding protein (G3BP). Moreover, the RNA-binding proteins codistributed after sucrose gradient centrifugation in PKP3-containing fractions corresponding to 25–35 S and 45–55 S. When cells are exposed to environmental stress (e.g., heat shock or oxidative stress) proteins FXR1, G3BP, and PABPC1 are found, together with PKP3 or PKP1, in “stress granules” known to accumulate stalled translation initiation complexes. Moreover, the protein eIF-4E and the ribosomal protein S6 are also detected in PKP3 particles. Our results show that cytoplasmic PKP3 is constitutively associated with RNA-binding proteins and indicate an involvement in processes of translation and RNA metabolism.

scholarly journals Single-molecule imaging reveals translation of mRNAs localized to stress granules

2020 ◽  
Author(s):  
Daniel Mateju ◽  
Bastian Eichenberger ◽  
Jan Eglinger ◽  
Gregory Roth ◽  
Jeffrey A. Chao
Keyword(s):  
Single Molecule ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Cellular Stress ◽  
Mrna Translation ◽  
Stress Granules ◽  
Living Cells ◽  
Single Molecule Imaging ◽  
Direct Role

SUMMARYCellular stress leads to reprogramming of mRNA translation and formation of stress granules (SGs), membraneless organelles consisting of mRNA and RNA-binding proteins. Although the function of SGs remains largely unknown, it is widely assumed they contain exclusively nontranslating mRNA. Here we re-examine this hypothesis using single-molecule imaging of mRNA translation in living cells. While our data confirms that non-translating mRNAs are preferentially recruited to SGs, we find unequivocal evidence for translation of mRNA localized to SGs. Our data indicate that SG-associated translation is not rare and that the entire translation cycle (initiation, elongation and termination) can occur for these transcripts. Furthermore, translating mRNAs can be observed transitioning between the cytosol and SGs without changing their translational status. Together, these results argue against a direct role for SGs in inhibition of mRNA translation.

scholarly journals Dr. Jekyll and Mr. Hyde? Physiology and Pathology of Neuronal Stress Granules

2021 ◽  
Vol 9 ◽  
Author(s):  
Pureum Jeon ◽  
Jin A. Lee
Keyword(s):  
Adaptive Response ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Mrna Translation ◽  
Stress Granules ◽  
Cell Type ◽  
Therapeutic Approaches ◽  
Lateral Sclerosis ◽  
Neuronal Stress

Stress granules (SGs) are membraneless cytosolic granules containing dense aggregations of RNA-binding proteins and RNAs. They appear in the cytosol under stress conditions and inhibit the initiation of mRNA translation. SGs are dynamically assembled under stressful conditions and rapidly disassembled after stress removal. They are heterogeneous in their RNA and protein content and are cell type- and stress-specific. In post-mitotic neurons, which do not divide, the dynamics of neuronal SGs are tightly regulated, implying that their dysregulation leads to neurodegeneration. Mutations in RNA-binding proteins are associated with SGs. SG components accumulate in cytosolic inclusions in many neurodegenerative diseases, such as frontotemporal dementia and amyotrophic lateral sclerosis. Although SGs primarily mediate a pro-survival adaptive response to cellular stress, abnormal persistent SGs might develop into aggregates and link to the pathogenesis of diseases. In this review, we present recent advances in the study of neuronal SGs in physiology and pathology, and discuss potential therapeutic approaches to remove abnormal, persistent SGs associated with neurodegeneration.

Dysfunctional RNA binding proteins and stress granules in multiple sclerosis

2018 ◽  
Vol 324 ◽  
pp. 149-156 ◽  
Author(s):  
Hannah E. Salapa ◽  
Chloe Johnson ◽  
Catherine Hutchinson ◽  
Bogdan F. Popescu ◽  
Michael C. Levin
Keyword(s):  
Multiple Sclerosis ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Stress Granules

scholarly journals G3BP–Caprin1–USP10 complexes mediate stress granule condensation and associate with 40S subunits

2016 ◽  
Vol 212 (7) ◽  
Author(s):  
Nancy Kedersha ◽  
Marc D. Panas ◽  
Christopher A. Achorn ◽  
Shawn Lyons ◽  
Sarah Tisdale ◽  
...  
Keyword(s):  
Osmotic Stress ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Stress Granules ◽  
Stress Granule ◽  
Initiation Factor ◽  
Eukaryotic Initiation Factor ◽  
Ribosomal Subunits ◽  
Partner Proteins

Mammalian stress granules (SGs) contain stalled translation preinitiation complexes that are assembled into discrete granules by specific RNA-binding proteins such as G3BP. We now show that cells lacking both G3BP1 and G3BP2 cannot form SGs in response to eukaryotic initiation factor 2α phosphorylation or eIF4A inhibition, but are still SG-competent when challenged with severe heat or osmotic stress. Rescue experiments using G3BP1 mutants show that G3BP1-F33W, a mutant unable to bind G3BP partner proteins Caprin1 or USP10, rescues SG formation. Caprin1/USP10 binding to G3BP is mutually exclusive: Caprin binding promotes, but USP10 binding inhibits, SG formation. G3BP interacts with 40S ribosomal subunits through its RGG motif, which is also required for G3BP-mediated SG formation. We propose that G3BP mediates the condensation of SGs by shifting between two different states that are controlled by binding to Caprin1 or USP10.

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