201
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Loh D, Reiter RJ. Melatonin: Regulation of Biomolecular Condensates in Neurodegenerative Disorders. Antioxidants (Basel) 2021; 10:1483. [PMID: 34573116 PMCID: PMC8465482 DOI: 10.3390/antiox10091483] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 09/10/2021] [Accepted: 09/13/2021] [Indexed: 12/12/2022] Open
Abstract
Biomolecular condensates are membraneless organelles (MLOs) that form dynamic, chemically distinct subcellular compartments organizing macromolecules such as proteins, RNA, and DNA in unicellular prokaryotic bacteria and complex eukaryotic cells. Separated from surrounding environments, MLOs in the nucleoplasm, cytoplasm, and mitochondria assemble by liquid-liquid phase separation (LLPS) into transient, non-static, liquid-like droplets that regulate essential molecular functions. LLPS is primarily controlled by post-translational modifications (PTMs) that fine-tune the balance between attractive and repulsive charge states and/or binding motifs of proteins. Aberrant phase separation due to dysregulated membrane lipid rafts and/or PTMs, as well as the absence of adequate hydrotropic small molecules such as ATP, or the presence of specific RNA proteins can cause pathological protein aggregation in neurodegenerative disorders. Melatonin may exert a dominant influence over phase separation in biomolecular condensates by optimizing membrane and MLO interdependent reactions through stabilizing lipid raft domains, reducing line tension, and maintaining negative membrane curvature and fluidity. As a potent antioxidant, melatonin protects cardiolipin and other membrane lipids from peroxidation cascades, supporting protein trafficking, signaling, ion channel activities, and ATPase functionality during condensate coacervation or dissolution. Melatonin may even control condensate LLPS through PTM and balance mRNA- and RNA-binding protein composition by regulating N6-methyladenosine (m6A) modifications. There is currently a lack of pharmaceuticals targeting neurodegenerative disorders via the regulation of phase separation. The potential of melatonin in the modulation of biomolecular condensate in the attenuation of aberrant condensate aggregation in neurodegenerative disorders is discussed in this review.
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Affiliation(s)
- Doris Loh
- Independent Researcher, Marble Falls, TX 78654, USA
| | - Russel J. Reiter
- Department of Cellular and Structural Biology, UT Health Science Center, San Antonio, TX 78229, USA
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202
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Kang W, Wang Y, Yang W, Zhang J, Zheng H, Li D. Research Progress on the Structure and Function of G3BP. Front Immunol 2021; 12:718548. [PMID: 34526993 PMCID: PMC8435845 DOI: 10.3389/fimmu.2021.718548] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 08/10/2021] [Indexed: 01/10/2023] Open
Abstract
Ras-GTPase-activating protein (SH3 domain)-binding protein (G3BP) is an RNA binding protein. G3BP is a key component of stress granules (SGs) and can interact with many host proteins to regulate the expression of SGs. As an antiviral factor, G3BP can interact with viral proteins to regulate the assembly of SGs and thus exert antiviral effects. However, many viruses can also use G3BP as a proximal factor and recruit translation initiation factors to promote viral proliferation. G3BP regulates mRNA translation and attenuation to regulate gene expression; therefore, it is closely related to diseases, such as cancer, embryonic death, arteriosclerosis, and neurodevelopmental disorders. This review discusses the important discoveries and developments related G3BP in the biological field over the past 20 years, which includes the formation of SGs, interaction with viruses, stability of RNA, and disease progression.
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Affiliation(s)
- Weifang Kang
- State Key Laboratory of Veterinary Etiological Biology and OIE/National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Yue Wang
- State Key Laboratory of Veterinary Etiological Biology and OIE/National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Wenping Yang
- State Key Laboratory of Veterinary Etiological Biology and OIE/National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Jing Zhang
- State Key Laboratory of Veterinary Etiological Biology and OIE/National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Haixue Zheng
- State Key Laboratory of Veterinary Etiological Biology and OIE/National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Dan Li
- State Key Laboratory of Veterinary Etiological Biology and OIE/National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
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203
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Markmiller S, Sathe S, Server KL, Nguyen TB, Fulzele A, Cody N, Javaherian A, Broski S, Finkbeiner S, Bennett EJ, Lécuyer E, Yeo GW. Persistent mRNA localization defects and cell death in ALS neurons caused by transient cellular stress. Cell Rep 2021; 36:109685. [PMID: 34496257 DOI: 10.1016/j.celrep.2021.109685] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 07/19/2021] [Accepted: 08/17/2021] [Indexed: 12/15/2022] Open
Abstract
Persistent cytoplasmic aggregates containing RNA binding proteins (RBPs) are central to the pathogenesis of late-onset neurodegenerative disorders such as amyotrophic lateral sclerosis (ALS). These aggregates share components, molecular mechanisms, and cellular protein quality control pathways with stress-induced RNA granules (SGs). Here, we assess the impact of stress on the global mRNA localization landscape of human pluripotent stem cell-derived motor neurons (PSC-MNs) using subcellular fractionation with RNA sequencing and proteomics. Transient stress disrupts subcellular RNA and protein distributions, alters the RNA binding profile of SG- and ALS-relevant RBPs and recapitulates disease-associated molecular changes such as aberrant splicing of STMN2. Although neurotypical PSC-MNs re-establish a normal subcellular localization landscape upon recovery from stress, cells harboring ALS-linked mutations are intransigent and display a delayed-onset increase in neuronal cell death. Our results highlight subcellular molecular distributions as predictive features and underscore the utility of cellular stress as a paradigm to study ALS-relevant mechanisms.
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Affiliation(s)
- Sebastian Markmiller
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA; Stem Cell Program, University of California, San Diego, La Jolla, CA 92093, USA; Institute for Genomic Medicine, University of California, San Diego, La Jolla, CA, 92039, USA
| | - Shashank Sathe
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA; Stem Cell Program, University of California, San Diego, La Jolla, CA 92093, USA; Institute for Genomic Medicine, University of California, San Diego, La Jolla, CA, 92039, USA
| | - Kari L Server
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA; Stem Cell Program, University of California, San Diego, La Jolla, CA 92093, USA; Institute for Genomic Medicine, University of California, San Diego, La Jolla, CA, 92039, USA
| | - Thai B Nguyen
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA; Stem Cell Program, University of California, San Diego, La Jolla, CA 92093, USA; Institute for Genomic Medicine, University of California, San Diego, La Jolla, CA, 92039, USA
| | - Amit Fulzele
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Neal Cody
- Institut de Recherches Cliniques de Montréal, Montréal, QC H2W 1R7, Canada
| | - Ashkan Javaherian
- Center for Systems and Therapeutics, Gladstone Institutes, San Francisco, CA 94158, USA; Taube/Koret Center for Neurodegenerative Disease Research, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Sara Broski
- Center for Systems and Therapeutics, Gladstone Institutes, San Francisco, CA 94158, USA; Taube/Koret Center for Neurodegenerative Disease Research, Gladstone Institutes, San Francisco, CA 94158, USA
| | - Steven Finkbeiner
- Center for Systems and Therapeutics, Gladstone Institutes, San Francisco, CA 94158, USA; Taube/Koret Center for Neurodegenerative Disease Research, Gladstone Institutes, San Francisco, CA 94158, USA; Departments of Neurology and Physiology, University of California-San Francisco, San Francisco, CA 94158, USA
| | - Eric J Bennett
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Eric Lécuyer
- Institut de Recherches Cliniques de Montréal, Montréal, QC H2W 1R7, Canada; Département de Biochimie et Médecine Moléculaire, Université de Montréal, Montréal, QC H3C 3J7, Canada; Division of Experimental Medicine, McGill University, Montréal, QC H3A 1A3, Canada
| | - Gene W Yeo
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA; Stem Cell Program, University of California, San Diego, La Jolla, CA 92093, USA; Institute for Genomic Medicine, University of California, San Diego, La Jolla, CA, 92039, USA.
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204
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Rengifo-Gonzalez JC, El Hage K, Clément MJ, Steiner E, Joshi V, Craveur P, Durand D, Pastré D, Bouhss A. The cooperative binding of TDP-43 to GU-rich RNA repeats antagonizes TDP-43 aggregation. eLife 2021; 10:67605. [PMID: 34490845 PMCID: PMC8523171 DOI: 10.7554/elife.67605] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 09/03/2021] [Indexed: 01/01/2023] Open
Abstract
TDP-43 is a nuclear RNA-binding protein that forms neuronal cytoplasmic inclusions in two major neurodegenerative diseases, ALS and FTLD. While the self-assembly of TDP-43 by its structured N-terminal and intrinsically disordered C-terminal domains has been widely studied, the mechanism by which mRNA preserves TDP-43 solubility in the nucleus has not been addressed. Here, we demonstrate that tandem RNA recognition motifs of TDP-43 bind to long GU-repeats in a cooperative manner through intermolecular interactions. Moreover, using mutants whose cooperativity is impaired, we found that the cooperative binding of TDP-43 to mRNA may be critical to maintain the solubility of TDP-43 in the nucleus and the miscibility of TDP-43 in cytoplasmic stress granules. We anticipate that the knowledge of a higher order assembly of TDP-43 on mRNA may clarify its role in intron processing and provide a means of interfering with the cytoplasmic aggregation of TDP-43.
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Affiliation(s)
- Juan Carlos Rengifo-Gonzalez
- Université Paris-Saclay, INSERM U1204, Univ Evry, Structure-Activité des Biomolécules Normales et Pathologiques (SABNP), Evry-Courcouronnes, France
| | - Krystel El Hage
- Université Paris-Saclay, INSERM U1204, Univ Evry, Structure-Activité des Biomolécules Normales et Pathologiques (SABNP), Evry-Courcouronnes, France
| | - Marie-Jeanne Clément
- Université Paris-Saclay, INSERM U1204, Univ Evry, Structure-Activité des Biomolécules Normales et Pathologiques (SABNP), Evry-Courcouronnes, France
| | - Emilie Steiner
- Université Paris-Saclay, INSERM U1204, Univ Evry, Structure-Activité des Biomolécules Normales et Pathologiques (SABNP), Evry-Courcouronnes, France
| | - Vandana Joshi
- Université Paris-Saclay, INSERM U1204, Univ Evry, Structure-Activité des Biomolécules Normales et Pathologiques (SABNP), Evry-Courcouronnes, France
| | | | - Dominique Durand
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - David Pastré
- Université Paris-Saclay, INSERM U1204, Univ Evry, Structure-Activité des Biomolécules Normales et Pathologiques (SABNP), Evry-Courcouronnes, France
| | - Ahmed Bouhss
- Université Paris-Saclay, INSERM U1204, Univ Evry, Structure-Activité des Biomolécules Normales et Pathologiques (SABNP), Evry-Courcouronnes, France
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205
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Cross-Talk between Oxidative Stress and m 6A RNA Methylation in Cancer. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2021; 2021:6545728. [PMID: 34484567 PMCID: PMC8416400 DOI: 10.1155/2021/6545728] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 07/03/2021] [Accepted: 08/06/2021] [Indexed: 12/14/2022]
Abstract
Oxidative stress is a state of imbalance between oxidation and antioxidation. Excessive ROS levels are an important factor in tumor development. Damage stimulation and excessive activation of oncogenes cause elevated ROS production in cancer, accompanied by an increase in the antioxidant capacity to retain redox homeostasis in tumor cells at an increased level. Although moderate concentrations of ROS produced in cancer cells contribute to maintaining cell survival and cancer progression, massive ROS accumulation can exert toxicity, leading to cancer cell death. RNA modification is a posttranscriptional control mechanism that regulates gene expression and RNA metabolism, and m6A RNA methylation is the most common type of RNA modification in eukaryotes. m6A modifications can modulate cellular ROS levels through different mechanisms. It is worth noting that ROS signaling also plays a regulatory role in m6A modifications. In this review, we concluded the effects of m6A modification and oxidative stress on tumor biological functions. In particular, we discuss the interplay between oxidative stress and m6A modifications.
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206
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Corbet GA, Burke JM, Parker R. ADAR1 limits stress granule formation through both translation-dependent and translation-independent mechanisms. J Cell Sci 2021; 134:272063. [PMID: 34397095 DOI: 10.1242/jcs.258783] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 08/05/2021] [Indexed: 11/20/2022] Open
Abstract
Stress granules (SGs) are cytoplasmic assemblies of RNA and protein that form when translation is repressed during the integrated stress response. SGs assemble from the combination of RNA-RNA, RNA-protein and protein-protein interactions between messenger ribonucleoprotein complexes (mRNPs). The protein adenosine deaminase acting on RNA 1 (ADAR1, also known as ADAR) recognizes and modifies double-stranded RNAs (dsRNAs) within cells to prevent an aberrant innate immune response. ADAR1 localizes to SGs, and since RNA-RNA interactions contribute to SG assembly and dsRNA induces SGs, we examined how ADAR1 affects SG formation. First, we demonstrate that ADAR1 depletion triggers SGs by allowing endogenous dsRNA to activate the integrated stress response through activation of PKR (also known as EIF2AK2) and translation repression. However, we also show that ADAR1 limits SG formation independently of translation inhibition. ADAR1 repression of SGs is independent of deaminase activity but is dependent on dsRNA-binding activity, suggesting a model where ADAR1 binding limits RNA-RNA and/or RNA-protein interactions necessary for recruitment to SGs. Given that ADAR1 expression is induced during viral infection, these findings have implications for the role of ADAR1 in the antiviral response. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Giulia A Corbet
- Department of Biochemistry, University of Colorado, Boulder, CO 80303, USA
| | - James M Burke
- Department of Biochemistry, University of Colorado, Boulder, CO 80303, USA
| | - Roy Parker
- Department of Biochemistry, University of Colorado, Boulder, CO 80303, USA.,Howard Hughes Medical Institute, 4000 Jones Bridge Road, Chevy Chase, MD 20815-6789, USA
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207
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Armas P, Coux G, Weiner AMJ, Calcaterra NB. What's new about CNBP? Divergent functions and activities for a conserved nucleic acid binding protein. Biochim Biophys Acta Gen Subj 2021; 1865:129996. [PMID: 34474118 DOI: 10.1016/j.bbagen.2021.129996] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 08/26/2021] [Indexed: 12/21/2022]
Abstract
BACKGROUND Cellular nucleic acid binding protein (CNBP) is a conserved single-stranded nucleic acid binding protein present in most eukaryotes, but not in plants. Expansions in the CNBP gene cause myotonic dystrophy type 2. Initially reported as a transcriptional regulator, CNBP was then also identified acting as a translational regulator. SCOPE OF REVIEW The focus of this review was to link the CNBP structural features and newly reported biochemical activities with the recently described biological functions, in the context of its pathological significance. MAJOR CONCLUSIONS Several post-translational modifications affect CNBP subcellular localization and activity. CNBP participates in the transcriptional and translational regulation of a wide range of genes by remodeling single-stranded nucleic acid secondary structures and/or by modulating the activity of trans-acting factors. CNBP is required for proper neural crest and heart development, and plays a role in cell proliferation control. Besides, CNBP has been linked with neurodegenerative, inflammatory, and congenital diseases, as well as with tumor processes. GENERAL SIGNIFICANCE This review provides an insight into the growing functions of CNBP in cell biology. A unique and robust mechanistic or biochemical connection among these roles has yet not been elucidated. However, the ability of CNBP to dynamically integrate signaling pathways and to act as nucleic acid chaperone may explain most of the roles and functions identified so far.
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Affiliation(s)
- Pablo Armas
- Instituto de Biología Molecular y Celular de Rosario (IBR), Consejo Nacional de Investigaciones Científicas y Técnicas (CONIeCET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Esmeralda y Ocampo 531, S2002LRK Rosario, Argentina
| | - Gabriela Coux
- Instituto de Biología Molecular y Celular de Rosario (IBR), Consejo Nacional de Investigaciones Científicas y Técnicas (CONIeCET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Esmeralda y Ocampo 531, S2002LRK Rosario, Argentina
| | - Andrea M J Weiner
- Instituto de Biología Molecular y Celular de Rosario (IBR), Consejo Nacional de Investigaciones Científicas y Técnicas (CONIeCET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Esmeralda y Ocampo 531, S2002LRK Rosario, Argentina
| | - Nora B Calcaterra
- Instituto de Biología Molecular y Celular de Rosario (IBR), Consejo Nacional de Investigaciones Científicas y Técnicas (CONIeCET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Esmeralda y Ocampo 531, S2002LRK Rosario, Argentina.
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208
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Xavier VJ, Martinou JC. RNA Granules in the Mitochondria and Their Organization under Mitochondrial Stresses. Int J Mol Sci 2021; 22:9502. [PMID: 34502411 PMCID: PMC8431320 DOI: 10.3390/ijms22179502] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 08/25/2021] [Accepted: 08/27/2021] [Indexed: 12/25/2022] Open
Abstract
The human mitochondrial genome (mtDNA) regulates its transcription products in specialised and distinct ways as compared to nuclear transcription. Thanks to its mtDNA mitochondria possess their own set of tRNAs, rRNAs and mRNAs that encode a subset of the protein subunits of the electron transport chain complexes. The RNA regulation within mitochondria is organised within specialised, membraneless, compartments of RNA-protein complexes, called the Mitochondrial RNA Granules (MRGs). MRGs were first identified to contain nascent mRNA, complexed with many proteins involved in RNA processing and maturation and ribosome assembly. Most recently, double-stranded RNA (dsRNA) species, a hybrid of the two complementary mRNA strands, were found to form granules in the matrix of mitochondria. These RNA granules are therefore components of the mitochondrial post-transcriptional pathway and as such play an essential role in mitochondrial gene expression. Mitochondrial dysfunctions in the form of, for example, RNA processing or RNA quality control defects, or inhibition of mitochondrial fission, can cause the loss or the aberrant accumulation of these RNA granules. These findings underline the important link between mitochondrial maintenance and the efficient expression of its genome.
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Affiliation(s)
| | - Jean-Claude Martinou
- Department of Cell Biology, Faculty of Sciences, University of Geneva, 1205 Geneva, Switzerland;
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209
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Mann JR, Donnelly CJ. RNA modulates physiological and neuropathological protein phase transitions. Neuron 2021; 109:2663-2681. [PMID: 34297914 PMCID: PMC8434763 DOI: 10.1016/j.neuron.2021.06.023] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 03/21/2021] [Accepted: 06/16/2021] [Indexed: 12/24/2022]
Abstract
Aggregation of RNA-binding proteins (RBPs) is a pathological hallmark of neurodegenerative disorders like amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). In these diseases, TDP-43 and FUS RBPs are depleted from the nuclear compartment, where they are normally localized, and found within cytoplasmic inclusions in degenerating regions of affected individuals' postmortem tissue. The mechanisms responsible for aggregation of these proteins has remained elusive, but recent studies suggest liquid-liquid phase separation (LLPS) might serve as a critical nucleation step in formation of pathological inclusions. The process of phase separation also underlies the formation and maintenance of several functional membraneless organelles (MLOs) throughout the cell, some of which contain TDP-43, FUS, and other disease-linked RBPs. One common ligand of disease-linked RBPs, RNA, is a major component of MLOs containing RBPs and has been demonstrated to be a strong modulator of RBP phase transitions. Although early evidence suggested a largely synergistic effect of RNA on RBP phase separation and MLO assembly, recent work indicates that RNA can also antagonize RBP phase behavior under certain physiological and pathological conditions. In this review, we describe the mechanisms underlying RNA-mediated phase transitions of RBPs and examine the molecular properties of these interactions, such as RNA length, sequence, and secondary structure, that mediate physiological or pathological LLPS.
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Affiliation(s)
- Jacob R Mann
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA 15213, USA; LiveLikeLouCenter for ALS Research, University of Pittsburgh Brain Institute, Pittsburgh, PA 15213, USA; Center for Protein Conformational Diseases, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Christopher J Donnelly
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA 15213, USA; Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; LiveLikeLouCenter for ALS Research, University of Pittsburgh Brain Institute, Pittsburgh, PA 15213, USA; Center for Protein Conformational Diseases, University of Pittsburgh, Pittsburgh, PA 15213, USA; Pittsburgh Institute for Neurodegeneration, University of Pittsburgh, Pittsburgh PA 15213.
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210
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Gutierrez‐Beltran E, Elander PH, Dalman K, Dayhoff GW, Moschou PN, Uversky VN, Crespo JL, Bozhkov PV. Tudor staphylococcal nuclease is a docking platform for stress granule components and is essential for SnRK1 activation in Arabidopsis. EMBO J 2021; 40:e105043. [PMID: 34287990 PMCID: PMC8447601 DOI: 10.15252/embj.2020105043] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 06/23/2021] [Accepted: 07/01/2021] [Indexed: 12/19/2022] Open
Abstract
Tudor staphylococcal nuclease (TSN; also known as Tudor-SN, p100, or SND1) is a multifunctional, evolutionarily conserved regulator of gene expression, exhibiting cytoprotective activity in animals and plants and oncogenic activity in mammals. During stress, TSN stably associates with stress granules (SGs), in a poorly understood process. Here, we show that in the model plant Arabidopsis thaliana, TSN is an intrinsically disordered protein (IDP) acting as a scaffold for a large pool of other IDPs, enriched for conserved stress granule components as well as novel or plant-specific SG-localized proteins. While approximately 30% of TSN interactors are recruited to stress granules de novo upon stress perception, 70% form a protein-protein interaction network present before the onset of stress. Finally, we demonstrate that TSN and stress granule formation promote heat-induced activation of the evolutionarily conserved energy-sensing SNF1-related protein kinase 1 (SnRK1), the plant orthologue of mammalian AMP-activated protein kinase (AMPK). Our results establish TSN as a docking platform for stress granule proteins, with an important role in stress signalling.
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Affiliation(s)
- Emilio Gutierrez‐Beltran
- Instituto de Bioquímica Vegetal y FotosíntesisConsejo Superior de Investigaciones Científicas (CSIC)‐Universidad de SevillaSevillaSpain
- Departamento de Bioquímica Vegetal y Biología MolecularFacultad de BiologíaUniversidad de SevillaSevillaSpain
| | - Pernilla H Elander
- Department of Molecular SciencesUppsala BioCenterSwedish University of Agricultural Sciences and Linnean Center for Plant BiologyUppsalaSweden
| | - Kerstin Dalman
- Department of Molecular SciencesUppsala BioCenterSwedish University of Agricultural Sciences and Linnean Center for Plant BiologyUppsalaSweden
| | - Guy W Dayhoff
- Department of ChemistryCollege of Art and SciencesUniversity of South FloridaTampaFLUSA
| | - Panagiotis N Moschou
- Institute of Molecular Biology and BiotechnologyFoundation for Research and Technology ‐ HellasHeraklionGreece
- Department of Plant BiologyUppsala BioCenterSwedish University of Agricultural Sciences and Linnean Center for Plant BiologyUppsalaSweden
- Department of BiologyUniversity of CreteHeraklionGreece
| | - Vladimir N Uversky
- Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute, Morsani College of MedicineUniversity of South FloridaTampaFLUSA
- Institute for Biological Instrumentation of the Russian Academy of SciencesFederal Research Center “Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences”PushchinoRussia
| | - Jose L Crespo
- Instituto de Bioquímica Vegetal y FotosíntesisConsejo Superior de Investigaciones Científicas (CSIC)‐Universidad de SevillaSevillaSpain
| | - Peter V Bozhkov
- Department of Molecular SciencesUppsala BioCenterSwedish University of Agricultural Sciences and Linnean Center for Plant BiologyUppsalaSweden
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211
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Almutairy BK, Alshetaili A, Anwer MK, Ali N. In silico identification of MicroRNAs targeting the key nucleator of stress granules, G3BP: Promising therapeutics for SARS-CoV-2 infection. Saudi J Biol Sci 2021; 28:7499-7504. [PMID: 34456603 PMCID: PMC8381622 DOI: 10.1016/j.sjbs.2021.08.056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 08/03/2021] [Accepted: 08/16/2021] [Indexed: 11/05/2022] Open
Abstract
Stress granules (SGs) are non-membrane ribonucleoprotein condensates formed in response to environmental stress conditions via liquid–liquid phase separation (LLPS). SGs are involved in the pathogenesis of aging and aging-associated diseases, cancers, viral infection, and several other diseases. GTPase-activating protein (SH3 domain)-binding protein 1 and 2 (G3BP1/2) is a key component and commonly used marker of SGs. Recent studies have shown that SARS-CoV-2 nucleocapsid protein via sequestration of G3BPs inhibits SGs formation in the host cells. In this study, we have identified putative miRNAs targeting G3BP in search of modulators of the G3BP expression. These miRNAs could be considered as new therapeutic targets against COVID-19 infection via the regulation of SG assembly and dynamics.
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Affiliation(s)
- Bjad K Almutairy
- Department of Pharmaceutics, College of Pharmacy, Prince Sattam Bin Abdulaziz University, Alkharj, 11942, Saudi Arabia
| | - Abdullah Alshetaili
- Department of Pharmaceutics, College of Pharmacy, Prince Sattam Bin Abdulaziz University, Alkharj, 11942, Saudi Arabia
| | - Md Khalid Anwer
- Department of Pharmaceutics, College of Pharmacy, Prince Sattam Bin Abdulaziz University, Alkharj, 11942, Saudi Arabia
| | - Nemat Ali
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia
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212
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Sun Y, Lu D, Yin Y, Song J, Liu Y, Hao W, Qi F, Zhang G, Zhang X, Liu L, Lin Z, Liang H, Zhao X, Jin Y, Yin Y. PTENα functions as an immune suppressor and promotes immune resistance in PTEN-mutant cancer. Nat Commun 2021; 12:5147. [PMID: 34446716 PMCID: PMC8390757 DOI: 10.1038/s41467-021-25417-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 08/04/2021] [Indexed: 01/12/2023] Open
Abstract
PTEN is frequently mutated in human cancers and PTEN mutants promote tumor progression and metastasis. PTEN mutations have been implicated in immune regulation, however, the underlying mechanism is largely unknown. Here, we report that PTENα, the isoform of PTEN, remains active in cancer bearing stop-gained PTEN mutations. Through counteraction of CD8+ T cell-mediated cytotoxicity, PTENα leads to T cell dysfunction and accelerates immune-resistant cancer progression. Clinical analysis further uncovers that PTENα-active mutations suppress host immune responses and result in poor prognosis in cancer as relative to PTENα-inactive mutations. Furthermore, germline deletion of Ptenα in mice increases cell susceptibility to immune attack through augmenting stress granule formation and limiting synthesis of peroxidases, leading to massive oxidative cell death and severe inflammatory damage. We propose that PTENα protects tumor from T cell killing and thus PTENα is a potential target in antitumor immunotherapy. PTENα is an N-terminally extended isoform of PTEN, a gene frequently mutated in human cancers. Here the authors show that PTENα remains active in PTEN-mutant cancers and is associated with tumor immune escape by promoting tumor cell resistance to T cell cytotoxicity.
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Affiliation(s)
- Yizhe Sun
- Institute of Systems Biomedicine, Department of Pathology, School of Basic Medical Sciences, Beijing Key Laboratory of Tumor Systems Biology, Peking University Health Science Center, Beijing, China
| | - Dan Lu
- Institute of Systems Biomedicine, Department of Pathology, School of Basic Medical Sciences, Beijing Key Laboratory of Tumor Systems Biology, Peking University Health Science Center, Beijing, China.
| | - Yue Yin
- Institute of Systems Biomedicine, Department of Pathology, School of Basic Medical Sciences, Beijing Key Laboratory of Tumor Systems Biology, Peking University Health Science Center, Beijing, China
| | - Jia Song
- Institute of Systems Biomedicine, Department of Pathology, School of Basic Medical Sciences, Beijing Key Laboratory of Tumor Systems Biology, Peking University Health Science Center, Beijing, China
| | - Yang Liu
- Institute of Systems Biomedicine, Department of Pathology, School of Basic Medical Sciences, Beijing Key Laboratory of Tumor Systems Biology, Peking University Health Science Center, Beijing, China
| | - Wenyan Hao
- Institute of Systems Biomedicine, Department of Pathology, School of Basic Medical Sciences, Beijing Key Laboratory of Tumor Systems Biology, Peking University Health Science Center, Beijing, China
| | - Fang Qi
- Institute of Systems Biomedicine, Department of Pathology, School of Basic Medical Sciences, Beijing Key Laboratory of Tumor Systems Biology, Peking University Health Science Center, Beijing, China
| | - Guangze Zhang
- Institute of Systems Biomedicine, Department of Pathology, School of Basic Medical Sciences, Beijing Key Laboratory of Tumor Systems Biology, Peking University Health Science Center, Beijing, China
| | - Xin Zhang
- Institute of Systems Biomedicine, Department of Pathology, School of Basic Medical Sciences, Beijing Key Laboratory of Tumor Systems Biology, Peking University Health Science Center, Beijing, China
| | - Liang Liu
- Institute of Systems Biomedicine, Department of Pathology, School of Basic Medical Sciences, Beijing Key Laboratory of Tumor Systems Biology, Peking University Health Science Center, Beijing, China
| | - Zhiqiang Lin
- Institute of Systems Biomedicine, Department of Pathology, School of Basic Medical Sciences, Beijing Key Laboratory of Tumor Systems Biology, Peking University Health Science Center, Beijing, China
| | - Hui Liang
- Institute of Systems Biomedicine, Department of Pathology, School of Basic Medical Sciences, Beijing Key Laboratory of Tumor Systems Biology, Peking University Health Science Center, Beijing, China
| | - Xuyang Zhao
- Institute of Systems Biomedicine, Department of Pathology, School of Basic Medical Sciences, Beijing Key Laboratory of Tumor Systems Biology, Peking University Health Science Center, Beijing, China
| | - Yan Jin
- Institute of Systems Biomedicine, Department of Pathology, School of Basic Medical Sciences, Beijing Key Laboratory of Tumor Systems Biology, Peking University Health Science Center, Beijing, China
| | - Yuxin Yin
- Institute of Systems Biomedicine, Department of Pathology, School of Basic Medical Sciences, Beijing Key Laboratory of Tumor Systems Biology, Peking University Health Science Center, Beijing, China. .,Peking-Tsinghua Center for Life Sciences, Peking University Health Science Center, Beijing, China. .,Institute of Precision Medicine, Peking University Shenzhen Hospital, Shenzhen, China.
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213
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Corbet GA, Wheeler JR, Parker R, Weskamp K. TDP43 ribonucleoprotein granules: physiologic function to pathologic aggregates. RNA Biol 2021; 18:128-138. [PMID: 34412568 DOI: 10.1080/15476286.2021.1963099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Ribonucleoprotein (RNP) assemblies are ubiquitous in eukaryotic cells and have functions throughout RNA transcription, splicing, and stability. Of the RNA-binding proteins that form RNPs, TAR DNA-binding protein of 43 kD (TDP43) is of particular interest due to its essential nature and its association with disease. TDP43 plays critical roles in RNA metabolism, many of which require its recruitment to RNP granules such as stress granules, myo-granules, and neuronal transport granules. Moreover, the presence of cytoplasmic TDP43-positive inclusions is a pathological hallmark of several neurodegenerative diseases. Despite the pervasiveness of TDP43 aggregates, TDP43 mutations are exceedingly rare, suggesting that aggregation may be linked to dysregulation of TDP43 function. Oligomerization is a part of normal TDP43 function; thus, it is of interest to understand what triggers the irreversible aggregation that is seen in disease. Herein, we examine TDP43 functions, particularly in RNP granules, and the mechanisms which may explain pathological TDP43 aggregation.
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Affiliation(s)
- Giulia Ada Corbet
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA
| | | | - Roy Parker
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA.,Department of Chemistry, Howard Hughes Medical Institute, Chevy Chase, MD, USA
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214
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Lee YB, Scotter EL, Lee DY, Troakes C, Mitchell J, Rogelj B, Gallo JM, Shaw CE. Cytoplasmic TDP-43 is involved in cell fate during stress recovery. Hum Mol Genet 2021; 31:166-175. [PMID: 34378050 PMCID: PMC8743001 DOI: 10.1093/hmg/ddab227] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 05/22/2021] [Accepted: 06/22/2021] [Indexed: 11/24/2022] Open
Abstract
Transactive response DNA binding protein 43 (TDP-43) is an RNA processing protein central to the pathogenesis of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Nuclear TDP-43 mislocalizes in patients to the cytoplasm, where it forms ubiquitin-positive inclusions in affected neurons and glia. Physiologically, cytoplasmic TDP-43 is associated with stress granules (SGs). Here, we explored TDP-43 cytoplasmic accumulation and stress granule formation following osmotic and oxidative stress. We show that sorbitol drives TDP-43 redistribution to the cytoplasm, while arsenite induces the recruitment of cytoplasmic TDP-43 to TIA-1 positive SGs. We demonstrate that inducing acute oxidative stress after TDP-43 cytoplasmic relocalization by osmotic shock induces poly (ADP-ribose) polymerase (PARP) cleavage, which triggers cellular toxicity. Recruitment of cytoplasmic TDP-43 to polyribosomes occurs in an SH-SY5Y cellular stress model and is observed in FTD brain lysate. Moreover, the processing body (P-body) marker DCP1a is detected in TDP-43 granules during recovery from stress. Overall, this study supports a central role for cytoplasmic TDP-43 in controlling protein translation in stressed cells.
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Affiliation(s)
- Youn-Bok Lee
- Department of Basic and Clinical Neuroscience Institute Maurice Wohl Clinical Neuroscience Institute of Psychiatry, Psychology and Neuroscience Kings College, SE5 9NU, London, U.K
| | - Emma L Scotter
- Centre for Brain Research, The University of Auckland, Auckland, New Zealand
| | - Do-Young Lee
- Department of Basic and Clinical Neuroscience Institute Maurice Wohl Clinical Neuroscience Institute of Psychiatry, Psychology and Neuroscience Kings College, SE5 9NU, London, U.K
| | - Claire Troakes
- Basic and Clinical Neuroscience Department, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Denmark Hill, SE5 8AF London U.K
| | - Jacqueline Mitchell
- Department of Basic and Clinical Neuroscience Institute Maurice Wohl Clinical Neuroscience Institute of Psychiatry, Psychology and Neuroscience Kings College, SE5 9NU, London, U.K
| | - Boris Rogelj
- Department of Biotechnology, Jozef Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia.,Biomedical Research Institute BRIS, Puhova 10, SI-1000 Ljubljana, Slovenia.,Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, SI-1000 Ljubljana, Slovenia
| | - Jean-Marc Gallo
- Department of Basic and Clinical Neuroscience Institute Maurice Wohl Clinical Neuroscience Institute of Psychiatry, Psychology and Neuroscience Kings College, SE5 9NU, London, U.K
| | - Christopher E Shaw
- Department of Basic and Clinical Neuroscience Institute Maurice Wohl Clinical Neuroscience Institute of Psychiatry, Psychology and Neuroscience Kings College, SE5 9NU, London, U.K.,UK Dementia Research Institute Centre, Institute of Psychiatry, Psychology and Neuroscience, Maurice Wohl Clinical Neuroscience Institute, 5 Cutcombe Road, Camberwell, SE5 9RT, London, U.K
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215
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Maruri-López I, Figueroa NE, Hernández-Sánchez IE, Chodasiewicz M. Plant Stress Granules: Trends and Beyond. FRONTIERS IN PLANT SCIENCE 2021; 12:722643. [PMID: 34434210 PMCID: PMC8381727 DOI: 10.3389/fpls.2021.722643] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 07/01/2021] [Indexed: 05/20/2023]
Abstract
Stress granules (SGs) are dynamic membrane-less condensates transiently assembled through liquid-liquid phase separation (LLPS) in response to stress. SGs display a biphasic architecture constituted of core and shell phases. The core is a conserved SG fraction fundamental for its assembly and consists primarily of proteins with intrinsically disordered regions and RNA-binding domains, along with translational-related proteins. The shell fraction contains specific SG components that differ among species, cell type, and developmental stage and might include metabolic enzymes, receptors, transcription factors, untranslated mRNAs, and small molecules. SGs assembly positively correlates with stalled translation associated with stress responses playing a pivotal role during the adaptive cellular response, post-stress recovery, signaling, and metabolic rewire. After stress, SG disassembly releases mRNA and proteins to the cytoplasm to reactivate translation and reassume cell growth and development. However, under severe stress conditions or aberrant cellular behavior, SG dynamics are severely disturbed, affecting cellular homeostasis and leading to cell death in the most critical cases. The majority of research on SGs has focused on yeast and mammals as model organism. Nevertheless, the study of plant SGs has attracted attention in the last few years. Genetics studies and adapted techniques from other non-plant models, such as affinity capture coupled with multi-omics analyses, have enriched our understanding of SG composition in plants. Despite these efforts, the investigation of plant SGs is still an emerging field in plant biology research. In this review, we compile and discuss the accumulated progress of plant SGs regarding their composition, organization, dynamics, regulation, and their relation to other cytoplasmic foci. Lastly, we will explore the possible connections among the most exciting findings of SGs from mammalian, yeast, and plants, which might help provide a complete view of the biology of plant SGs in the future.
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Affiliation(s)
| | | | | | - Monika Chodasiewicz
- Biological and Environmental Science and Engineering Division, Center for Desert Agriculture, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
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216
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Ismail H, Liu X, Yang F, Li J, Zahid A, Dou Z, Liu X, Yao X. Mechanisms and regulation underlying membraneless organelle plasticity control. J Mol Cell Biol 2021; 13:239-258. [PMID: 33914074 PMCID: PMC8339361 DOI: 10.1093/jmcb/mjab028] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Revised: 03/31/2021] [Accepted: 04/06/2021] [Indexed: 12/11/2022] Open
Abstract
Evolution has enabled living cells to adopt their structural and functional complexity by organizing intricate cellular compartments, such as membrane-bound and membraneless organelles (MLOs), for spatiotemporal catalysis of physiochemical reactions essential for cell plasticity control. Emerging evidence and view support the notion that MLOs are built by multivalent interactions of biomolecules via phase separation and transition mechanisms. In healthy cells, dynamic chemical modifications regulate MLO plasticity, and reversible phase separation is essential for cell homeostasis. Emerging evidence revealed that aberrant phase separation results in numerous neurodegenerative disorders, cancer, and other diseases. In this review, we provide molecular underpinnings on (i) mechanistic understanding of phase separation, (ii) unifying structural and mechanistic principles that underlie this phenomenon, (iii) various mechanisms that are used by cells for the regulation of phase separation, and (iv) emerging therapeutic and other applications.
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Affiliation(s)
- Hazrat Ismail
- MOE Key Laboratory for Membraneless Organelles & Cellular Dynamics and CAS Center for Excellence in Molecular Cell Science, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230027, China
| | - Xu Liu
- MOE Key Laboratory for Membraneless Organelles & Cellular Dynamics and CAS Center for Excellence in Molecular Cell Science, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230027, China
- Keck Center for Organoids Plasticity Control, Atlanta, GA 30310, USA
| | - Fengrui Yang
- MOE Key Laboratory for Membraneless Organelles & Cellular Dynamics and CAS Center for Excellence in Molecular Cell Science, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230027, China
- Keck Center for Organoids Plasticity Control, Atlanta, GA 30310, USA
| | - Junying Li
- MOE Key Laboratory for Membraneless Organelles & Cellular Dynamics and CAS Center for Excellence in Molecular Cell Science, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230027, China
- Anhui Key Laboratory for Cellular Dynamics & Chemical Biology, Hefei 230027, China
| | - Ayesha Zahid
- MOE Key Laboratory for Membraneless Organelles & Cellular Dynamics and CAS Center for Excellence in Molecular Cell Science, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230027, China
| | - Zhen Dou
- MOE Key Laboratory for Membraneless Organelles & Cellular Dynamics and CAS Center for Excellence in Molecular Cell Science, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230027, China
| | - Xing Liu
- MOE Key Laboratory for Membraneless Organelles & Cellular Dynamics and CAS Center for Excellence in Molecular Cell Science, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230027, China
- Anhui Key Laboratory for Cellular Dynamics & Chemical Biology, Hefei 230027, China
| | - Xuebiao Yao
- MOE Key Laboratory for Membraneless Organelles & Cellular Dynamics and CAS Center for Excellence in Molecular Cell Science, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230027, China
- Anhui Key Laboratory for Cellular Dynamics & Chemical Biology, Hefei 230027, China
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217
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Xu H, Bensalel J, Capobianco E, Lu ML, Wei J. Impaired Restoration of Global Protein Synthesis Contributes to Increased Vulnerability to Acute ER Stress Recovery in Huntington's Disease. Cell Mol Neurobiol 2021; 42:2757-2771. [PMID: 34347195 DOI: 10.1007/s10571-021-01137-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 07/28/2021] [Indexed: 12/21/2022]
Abstract
Neurons are susceptible to different cellular stresses and this vulnerability has been implicated in the pathogenesis of Huntington's disease (HD). Accumulating evidence suggest that acute or chronic stress, depending on its duration and severity, can cause irreversible cellular damages to HD neurons, which contributes to neurodegeneration. In contrast, how normal and HD neurons respond during the resolution of a cellular stress remain less explored. In this study, we challenged normal and HD cells with a low-level acute ER stress and examined the molecular and cellular responses after stress removal. Using both striatal cell lines and primary neurons, we first showed the temporal activation of p-eIF2α-ATF4-GADD34 pathway in response to the acute ER stress and during recovery between normal and HD cells. HD cells were more vulnerable to cell death during stress recovery and were associated with increased number of apoptotic/necrotic cells and decreased cell proliferation. This is also supported by the Gene Ontology analysis from the RNA-seq data which indicated that "apoptosis-related Biological Processes" were more enriched in HD cells during stress recovery. We further showed that HD cells were defective in restoring global protein synthesis during stress recovery and promoting protein synthesis by an integrated stress response inhibitor, ISRIB, could attenuate cell death in HD cells. Together, these data suggest that normal and HD cells undergo distinct mechanisms of transcriptional reprogramming, leading to different cell fate decisions during the stress recovery.
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Affiliation(s)
- Hongyuan Xu
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, 33431, USA
| | - Johanna Bensalel
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, 33431, USA
| | - Enrico Capobianco
- Institute of Data Science and Computing, University of Miami, Miami, FL, 33146, USA
| | - Michael L Lu
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, 33431, USA
| | - Jianning Wei
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, 33431, USA.
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218
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Liu YJ, Chern Y. Contribution of Energy Dysfunction to Impaired Protein Translation in Neurodegenerative Diseases. Front Cell Neurosci 2021; 15:668500. [PMID: 34393724 PMCID: PMC8355359 DOI: 10.3389/fncel.2021.668500] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 07/09/2021] [Indexed: 12/14/2022] Open
Abstract
Impaired energy homeostasis and aberrant translational control have independently been implicated in the pathogenesis of neurodegenerative diseases. AMP kinase (AMPK), regulated by the ratio of cellular AMP and ATP, is a major gatekeeper for cellular energy homeostasis. Abnormal regulation of AMPK has been reported in several neurodegenerative diseases, including Alzheimer’s disease (AD) and amyotrophic lateral sclerosis (ALS). Most importantly, AMPK activation is known to suppress the translational machinery by inhibiting the mechanistic target of rapamycin complex 1 (mTORC1), activating translational regulators, and phosphorylating nuclear transporter factors. In this review, we describe recent findings on the emerging role of protein translation impairment caused by energy dysregulation in neurodegenerative diseases.
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Affiliation(s)
- Yu-Ju Liu
- Division of Neuroscience, Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Yijuang Chern
- Division of Neuroscience, Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
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219
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SILAC-based quantitative MS approach reveals Withaferin A regulated proteins in prostate cancer. J Proteomics 2021; 247:104334. [PMID: 34298187 DOI: 10.1016/j.jprot.2021.104334] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 06/30/2021] [Accepted: 07/16/2021] [Indexed: 01/06/2023]
Abstract
Withaferin A (WA) is a steroidal lactone extracted from Withania somnifera, commonly known as Ashwagandha. WA has several therapeutic benefits. The current study aims to identify proteins that are potentially regulated by WA in prostate cancer (PCA) cells. We used a SILAC-based proteomic approach to analyze the expression of proteins in response to WA treatment at 4 h and 24 h time points in three PCA cell lines: 22Rv1, DU-145, and LNCaP. Ontology analysis suggested that prolonged treatment with WA upregulated the expression of proteins involved in stress-response pathways. Treatment with WA increased oxidative stress, reduced global mRNA translation, and elevated the expression of cytoprotective stress granule (SG) protein G3BP1. WA treatment also enhanced the formation of SGs. The elevated expression of G3BP1 and the formation of SGs might constitute a mechanism of cytoprotection in PCA cells. Knockdown of G3BP1 blocked SG formation and enhanced the efficacy of WA to reduce PCA cell survival. SIGNIFICANCE: Withaferin A, a steroidal lactone, extracted from Withania somnifera is a promising anti-cancer drug. Using a SILAC-based quantitative proteomic approach, we identified proteins changed by WA-treatment at 4 h and 24 h in three prostate cancer (PCA) cell lines. WA-treatment induced the expression of proteins involved in apoptosis and reduced the expression of proteins involved in cell growth at 4 h. WA-treatment for 24 h enhanced the expression of proteins involved in stress response pathways. WA-treated cells exhibited increased oxidative stress, reduced mRNA translation and enhanced SG formation. PCA is characterized by higher metabolic rate and increased oxidative stress. PCA with a higher stress tolerance can effectively adapt to anti-cancer treatment stress, leading to drug resistance and cellular protection. Enhancing the level of oxidative stress along with inhibition of corresponding cytoprotective stress response pathways is a feasible option to prevent PCA from getting adapted to treatment stress. WA-treatment induced oxidative stress, in combination with blocking SGs by G3BP1 targeting, offers a therapeutic strategy to reduce PCA cell survival.
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220
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Nesterov SV, Ilyinsky NS, Uversky VN. Liquid-liquid phase separation as a common organizing principle of intracellular space and biomembranes providing dynamic adaptive responses. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2021; 1868:119102. [PMID: 34293345 DOI: 10.1016/j.bbamcr.2021.119102] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 07/13/2021] [Accepted: 07/18/2021] [Indexed: 02/07/2023]
Abstract
This work is devoted to the phenomenon of liquid-liquid phase separation (LLPS), which has come to be recognized as fundamental organizing principle of living cells. We distinguish separation processes with different dimensions. Well-known 3D-condensation occurs in aqueous solution and leads to membraneless organelle (MLOs) formation. 2D-films may be formed near membrane surfaces and lateral phase separation (membrane rafts) occurs within the membranes themselves. LLPS may also occur on 1D structures like DNA and the cyto- and nucleoskeleton. Phase separation provides efficient transport and sorting of proteins and metabolites, accelerates the assembly of metabolic and signaling complexes, and mediates stress responses. In this work, we propose a model in which the processes of polymerization (1D structures), phase separation in membranes (2D structures), and LLPS in the volume (3D structures) influence each other. Disordered proteins and whole condensates may provide membrane raft separation or polymerization of specific proteins. On the other hand, 1D and 2D structures with special composition or embedded IDRs can nucleate condensates. We hypothesized that environmental change may trigger a LLPS which can propagate within the cell interior moving along the cytoskeleton or as an autowave. New phase propagation quickly and using a low amount of energy adjusts cell signaling and metabolic systems to new demands. Cumulatively, the interconnected phase separation phenomena in different dimensions represent a previously unexplored system of intracellular communication and regulation which cannot be ignored when considering both physiological and pathological cell processes.
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Affiliation(s)
- Semen V Nesterov
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Institutskiy pereulok, 9, Dolgoprudny 141700, Russia; Kurchatov Complex of NBICS-Technologies, National Research Center Kurchatov Institute, Moscow 123182, Russia.
| | - Nikolay S Ilyinsky
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Institutskiy pereulok, 9, Dolgoprudny 141700, Russia
| | - Vladimir N Uversky
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Institutskiy pereulok, 9, Dolgoprudny 141700, Russia; Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, 12901 Bruce B. Downs Blvd., MDC07, Tampa, FL 33612, USA.
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221
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Magliozzi JO, Moseley JB. Pak1 kinase controls cell shape through ribonucleoprotein granules. eLife 2021; 10:67648. [PMID: 34282727 PMCID: PMC8318594 DOI: 10.7554/elife.67648] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 07/19/2021] [Indexed: 11/29/2022] Open
Abstract
Fission yeast cells maintain a rod shape due to conserved signaling pathways that organize the cytoskeleton for polarized growth. We discovered a mechanism linking the conserved protein kinase Pak1 with cell shape through the RNA-binding protein Sts5. Pak1 (also called Shk1 and Orb2) prevents Sts5 association with P bodies by directly phosphorylating its intrinsically disordered region (IDR). Pak1 and the cell polarity kinase Orb6 both phosphorylate the Sts5 IDR but at distinct residues. Mutations preventing phosphorylation in the Sts5 IDR cause increased P body formation and defects in cell shape and polarity. Unexpectedly, when cells encounter glucose starvation, PKA signaling triggers Pak1 recruitment to stress granules with Sts5. Through retargeting experiments, we reveal that Pak1 localizes to stress granules to promote rapid dissolution of Sts5 upon glucose addition. Our work reveals a new role for Pak1 in regulating cell shape through ribonucleoprotein granules during normal and stressed growth conditions.
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Affiliation(s)
- Joseph O Magliozzi
- Department of Biochemistry and Cell Biology, The Geisel School of Medicine at Dartmouth, Hanover, United States
| | - James B Moseley
- Department of Biochemistry and Cell Biology, The Geisel School of Medicine at Dartmouth, Hanover, United States
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222
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Huntingtin and Its Role in Mechanisms of RNA-Mediated Toxicity. Toxins (Basel) 2021; 13:toxins13070487. [PMID: 34357961 PMCID: PMC8310054 DOI: 10.3390/toxins13070487] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 07/09/2021] [Accepted: 07/11/2021] [Indexed: 12/20/2022] Open
Abstract
Huntington’s disease (HD) is caused by a CAG-repeat expansion mutation in the Huntingtin (HTT) gene. It is characterized by progressive psychiatric and neurological symptoms in combination with a progressive movement disorder. Despite the ubiquitous expression of HTT, pathological changes occur quite selectively in the central nervous system. Since the discovery of HD more than 150 years ago, a lot of research on molecular mechanisms contributing to neurotoxicity has remained the focal point. While traditionally, the protein encoded by the HTT gene remained the cynosure for researchers and was extensively reviewed elsewhere, several studies in the last few years clearly indicated the contribution of the mutant RNA transcript to cellular dysfunction as well. In this review, we outline recent studies on RNA-mediated molecular mechanisms that are linked to cellular dysfunction in HD models. These mechanisms include mis-splicing, aberrant translation, deregulation of the miRNA machinery, deregulated RNA transport and abnormal regulation of mitochondrial RNA. Furthermore, we summarize recent therapeutical approaches targeting the mutant HTT transcript. While currently available treatments are of a palliative nature only and do not halt the disease progression, recent clinical studies provide hope that these novel RNA-targeting strategies will lead to better therapeutic approaches.
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223
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Saito Y, Kimura W. Roles of Phase Separation for Cellular Redox Maintenance. Front Genet 2021; 12:691946. [PMID: 34306032 PMCID: PMC8299301 DOI: 10.3389/fgene.2021.691946] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 06/04/2021] [Indexed: 12/12/2022] Open
Abstract
The oxidation reaction greatly alters characteristics of various cellular components. In exchange for efficient energy production, mitochondrial aerobic respiration substantially increases the risk of excess oxidation of cellular biomolecules such as lipids, proteins, nucleic acids, and numerous small molecules. To maintain a physiologically balanced cellular reduction-oxidation (redox) state, cells utilize a variety of molecular machineries including cellular antioxidants and protein degradation complexes such as the ubiquitin-proteasome system or autophagy. In the past decade, biomolecular liquid-liquid phase separation (LLPS) has emerged as a subject of great interest in the biomedical field, as it plays versatile roles in the maintenance of cellular homeostasis. With regard to redox homeostasis, LLPS arose as a major player in both well-characterized and newly emerging redox pathways. LLPS is involved in direct redox imbalance sensing, signal transduction, and transcriptional regulation. Also, LLPS is at play when cells resist redox imbalance through metabolic switching, translational remodeling, activating the DNA damage response, and segregation of vulnerable lipids and proteins. On the other hand, chronic accumulation of phase-separated molecular condensates such as lipid droplets and amyloid causes neurotoxic outcomes. In this review we enumerate recent progress on understanding how cells utilize LLPS to deal with oxidative stress, especially related to cell survival or pathogenesis, and we discuss future research directions for understanding biological phase separation in cellular redox regulation.
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Affiliation(s)
- Yuichi Saito
- Laboratory for Heart Regeneration, RIKEN Center for Biosystems Dynamics Research, Kobe, Japan
| | - Wataru Kimura
- Laboratory for Heart Regeneration, RIKEN Center for Biosystems Dynamics Research, Kobe, Japan
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224
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Roy N, Sundar S, Pillai M, Patell-Socha F, Ganesh S, Aloysius A, Rumman M, Gala H, Hughes SM, Zammit PS, Dhawan J. mRNP granule proteins Fmrp and Dcp1a differentially regulate mRNP complexes to contribute to control of muscle stem cell quiescence and activation. Skelet Muscle 2021; 11:18. [PMID: 34238354 PMCID: PMC8265057 DOI: 10.1186/s13395-021-00270-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 04/28/2021] [Indexed: 01/28/2023] Open
Abstract
Background During skeletal muscle regeneration, satellite stem cells use distinct pathways to repair damaged myofibers or to self-renew by returning to quiescence. Cellular/mitotic quiescence employs mechanisms that promote a poised or primed state, including altered RNA turnover and translational repression. Here, we investigate the role of mRNP granule proteins Fragile X Mental Retardation Protein (Fmrp) and Decapping protein 1a (Dcp1a) in muscle stem cell quiescence and differentiation. Methods Using isolated single muscle fibers from adult mice, we established differential enrichment of mRNP granule proteins including Fmrp and Dcp1a in muscle stem cells vs. myofibers. We investigated muscle tissue homeostasis in adult Fmr1-/- mice, analyzing myofiber cross-sectional area in vivo and satellite cell proliferation ex vivo. We explored the molecular mechanisms of Dcp1a and Fmrp function in quiescence, proliferation and differentiation in a C2C12 culture model. Here, we used polysome profiling, imaging and RNA/protein expression analysis to establish the abundance and assembly status of mRNP granule proteins in different cellular states, and the phenotype of knockdown cells. Results Quiescent muscle satellite cells are enriched for puncta containing the translational repressor Fmrp, but not the mRNA decay factor Dcp1a. MuSC isolated from Fmr1-/- mice exhibit defective proliferation, and mature myofibers show reduced cross-sectional area, suggesting a role for Fmrp in muscle homeostasis. Expression and organization of Fmrp and Dcp1a varies during primary MuSC activation on myofibers, with Fmrp puncta prominent in quiescence, but Dcp1a puncta appearing during activation/proliferation. This reciprocal expression of Fmrp and Dcp1a puncta is recapitulated in a C2C12 culture model of quiescence and activation: consistent with its role as a translational repressor, Fmrp is enriched in non-translating mRNP complexes abundant in quiescent myoblasts; Dcp1a puncta are lost in quiescence, suggesting stabilized and repressed transcripts. The function of each protein differs during proliferation; whereas Fmrp knockdown led to decreased proliferation and lower cyclin expression, Dcp1a knockdown led to increased cell proliferation and higher cyclin expression. However, knockdown of either Fmrp or Dcp1a led to compromised differentiation. We also observed cross-regulation of decay versus storage mRNP granules; knockdown of Fmrp enhances accumulation of Dcp1a puncta, whereas knockdown of Dcp1a leads to increased Fmrp in puncta. Conclusions Taken together, our results provide evidence that the balance of mRNA turnover versus utilization is specific for distinct cellular states. Supplementary Information The online version contains supplementary material available at 10.1186/s13395-021-00270-9.
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Affiliation(s)
- Nainita Roy
- Institute for Stem Cell Science and Regenerative Medicine, Bangalore, India
| | - Swetha Sundar
- Centre for Cellular and Molecular Biology, Hyderabad, India
| | - Malini Pillai
- Institute for Stem Cell Science and Regenerative Medicine, Bangalore, India
| | - Farah Patell-Socha
- Institute for Stem Cell Science and Regenerative Medicine, Bangalore, India
| | - Sravya Ganesh
- Institute for Stem Cell Science and Regenerative Medicine, Bangalore, India
| | - Ajoy Aloysius
- National Center for Biological Sciences, Bangalore, India
| | - Mohammed Rumman
- Institute for Stem Cell Science and Regenerative Medicine, Bangalore, India.,Manipal Academy of Higher Education, Manipal, India
| | - Hardik Gala
- Institute for Stem Cell Science and Regenerative Medicine, Bangalore, India.,Centre for Cellular and Molecular Biology, Hyderabad, India
| | - Simon M Hughes
- King's College London, Randall Centre for Cell & Molecular Biophysics, New Hunt's House, Guy's Campus, London, UK
| | - Peter S Zammit
- King's College London, Randall Centre for Cell & Molecular Biophysics, New Hunt's House, Guy's Campus, London, UK
| | - Jyotsna Dhawan
- Institute for Stem Cell Science and Regenerative Medicine, Bangalore, India. .,Centre for Cellular and Molecular Biology, Hyderabad, India.
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225
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Orti F, Navarro AM, Rabinovich A, Wodak SJ, Marino-Buslje C. Insight into membraneless organelles and their associated proteins: Drivers, Clients and Regulators. Comput Struct Biotechnol J 2021; 19:3964-3977. [PMID: 34377363 PMCID: PMC8318826 DOI: 10.1016/j.csbj.2021.06.042] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Revised: 06/26/2021] [Accepted: 06/27/2021] [Indexed: 02/06/2023] Open
Abstract
In recent years, attention has been devoted to proteins forming immiscible liquid phases within the liquid intracellular medium, commonly referred to as membraneless organelles (MLO). These organelles enable the spatiotemporal associations of cellular components that exchange dynamically with the cellular milieu. The dysregulation of these liquid-liquid phase separation processes (LLPS) may cause various diseases including neurodegenerative pathologies and cancer, among others. Until very recently, databases containing information on proteins forming MLOs, as well as tools and resources facilitating their analysis, were missing. This has recently changed with the publication of 4 databases that focus on different types of experiments, sets of proteins, inclusion criteria, and levels of annotation or curation. In this study we integrate and analyze the information across these databases, complement their records, and produce a consolidated set of proteins that enables the investigation of the LLPS phenomenon. To gain insight into the features that characterize different types of MLOs and the roles of their associated proteins, they were grouped into categories: High Confidence MLO associated (including Drivers and reviewed proteins), Potential Clients and Regulators, according to their annotated functions. We show that none of the databases taken alone covers the data sufficiently to enable meaningful analysis, validating our integration effort as essential for gaining better understanding of phase separation and laying the foundations for the discovery of new proteins potentially involved in this important cellular process. Lastly, we developed a server, enabling customized selections of different sets of proteins based on MLO location, database, disorder content, among other attributes (https://forti.shinyapps.io/mlos/).
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Affiliation(s)
- Fernando Orti
- Bioinformatics Unit, Fundación Instituto Leloir. Avda. Patricias Argentinas 435, Buenos Aires B1405WE, Argentina
| | - Alvaro M. Navarro
- Bioinformatics Unit, Fundación Instituto Leloir. Avda. Patricias Argentinas 435, Buenos Aires B1405WE, Argentina
| | - Andres Rabinovich
- Bioinformatics Unit, Fundación Instituto Leloir. Avda. Patricias Argentinas 435, Buenos Aires B1405WE, Argentina
| | - Shoshana J. Wodak
- VIB-VUB Center for Structural Biology, Flemish Institute for Biotechnology, Brussels, Belgium
- Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Cristina Marino-Buslje
- Bioinformatics Unit, Fundación Instituto Leloir. Avda. Patricias Argentinas 435, Buenos Aires B1405WE, Argentina
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226
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Wang L, Yang W, Li B, Yuan S, Wang F. Response to stress in biological disorders: Implications of stress granule assembly and function. Cell Prolif 2021; 54:e13086. [PMID: 34170048 PMCID: PMC8349659 DOI: 10.1111/cpr.13086] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 06/06/2021] [Accepted: 06/07/2021] [Indexed: 12/17/2022] Open
Abstract
It is indispensable for cells to adapt and respond to environmental stresses, in order for organisms to survive. Stress granules (SGs) are condensed membrane‐less organelles dynamically formed in the cytoplasm of eukaryotes cells to cope with diverse intracellular or extracellular stress factors, with features of liquid‐liquid phase separation. They are composed of multiple constituents, including translationally stalled mRNAs, translation initiation factors, RNA‐binding proteins and also non‐RNA‐binding proteins. SG formation is triggered by stress stimuli, viral infection and signal transduction, while aberrant assembly of SGs may contribute to tissue degenerative diseases. Recently, a growing body of evidence has emerged on SG response mechanisms for cells facing high temperatures, oxidative stress and osmotic stress. In this review, we aim to summarize factors affecting SGs assembly, present the impact of SGs on germ cell development and other biological processes. We particularly emphasize the significance of recently reported RNA modifications in SG stress responses. In parallel, we also review all current perspectives on the roles of SGs in male germ cells, with a particular focus on the dynamics of SG assembly.
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Affiliation(s)
- Lingjuan Wang
- Institute Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Hubei, China
| | - Weina Yang
- Institute Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Hubei, China
| | - Bin Li
- Tianjin Medical University General Hospital, Tianjin, China.,State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China
| | - Shuiqiao Yuan
- Institute Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Hubei, China
| | - Fengli Wang
- Institute Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Hubei, China
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227
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Stress granule formation, disassembly, and composition are regulated by alphavirus ADP-ribosylhydrolase activity. Proc Natl Acad Sci U S A 2021; 118:2021719118. [PMID: 33547245 DOI: 10.1073/pnas.2021719118] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
While biomolecular condensates have emerged as an important biological phenomenon, mechanisms regulating their composition and the ways that viruses hijack these mechanisms remain unclear. The mosquito-borne alphaviruses cause a range of diseases from rashes and arthritis to encephalitis, and no licensed drugs are available for treatment or vaccines for prevention. The alphavirus virulence factor nonstructural protein 3 (nsP3) suppresses the formation of stress granules (SGs)-a class of cytoplasmic condensates enriched with translation initiation factors and formed during the early stage of infection. nsP3 has a conserved N-terminal macrodomain that hydrolyzes ADP-ribose from ADP-ribosylated proteins and a C-terminal hypervariable domain that binds the essential SG component G3BP1. Here, we show that macrodomain hydrolase activity reduces the ADP-ribosylation of G3BP1, disassembles virus-induced SGs, and suppresses SG formation. Expression of nsP3 results in the formation of a distinct class of condensates that lack translation initiation factors but contain G3BP1 and other SG-associated RNA-binding proteins. Expression of ADP-ribosylhydrolase-deficient nsP3 results in condensates that retain translation initiation factors as well as RNA-binding proteins, similar to SGs. Therefore, our data reveal that ADP-ribosylation controls the composition of biomolecular condensates, specifically the localization of translation initiation factors, during alphavirus infection.
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228
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Fare CM, Villani A, Drake LE, Shorter J. Higher-order organization of biomolecular condensates. Open Biol 2021; 11:210137. [PMID: 34129784 PMCID: PMC8205532 DOI: 10.1098/rsob.210137] [Citation(s) in RCA: 73] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
A guiding principle of biology is that biochemical reactions must be organized in space and time. One way this spatio-temporal organization is achieved is through liquid–liquid phase separation (LLPS), which generates biomolecular condensates. These condensates are dynamic and reactive, and often contain a complex mixture of proteins and nucleic acids. In this review, we discuss how underlying physical and chemical processes generate internal condensate architectures. We then outline the diverse condensate architectures that are observed in biological systems. Finally, we discuss how specific condensate organization is critical for specific biological functions.
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Affiliation(s)
- Charlotte M Fare
- Department of Biochemistry and Biophysics, and.,Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | | | | | - James Shorter
- Department of Biochemistry and Biophysics, and.,Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
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229
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Riley JF, Fioramonti PJ, Rusnock AK, Hehnly H, Castañeda CA. ALS-linked mutations impair UBQLN2 stress-induced biomolecular condensate assembly in cells. J Neurochem 2021; 159:145-155. [PMID: 34129687 DOI: 10.1111/jnc.15453] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 05/30/2021] [Accepted: 06/13/2021] [Indexed: 11/28/2022]
Abstract
Mutations in Ubiquilin-2 (UBQLN2), a ubiquitin-binding shuttle protein involved in several protein quality control processes, can lead to amyotrophic lateral sclerosis (ALS). We previously found that wild-type UBQLN2 forms dynamic, membraneless biomolecular condensates upon cellular stress, and undergoes liquid-liquid phase separation in vitro. However, the impact of ALS-linked mutations on UBQLN2 condensate formation in cells is unknown. Here, we employ live-cell imaging and photokinetic analysis to investigate how five patient-derived ALS-linked mutations in UBQLN2 impact stress-induced UBQLN2 condensate assembly and condensate material properties. Both wild-type and mutant UBQLN2 condensates are generally cytoplasmic and liquid-like. However, cells transfected with mutant UBQLN2 contain fewer stress-induced UBQLN2 condensates than those with wild-type UBQLN2. Most strikingly, exogenously expressed P506T UBQLN2 forms the lowest number of stress-induced condensates of all UBQLN2 mutants, and these condensates are significantly smaller than those of wild-type UBQLN2. Fluorescence recovery after photobleaching (FRAP) analysis of UBQLN2 condensates revealed higher immobile fractions for UBQLN2 mutants, especially P506T. P497S and P497H mutations differentially impact condensate properties, demonstrating that the effects of ALS-linked mutations are both position- and amino acid-dependent. Collectively, our data show that disease mutations hinder assembly and alter viscoelastic properties of stress-induced UBQLN2 condensates, potentially leading to aggregates commonly observed in ALS.
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Affiliation(s)
- Julia F Riley
- Department of Biology, Syracuse University, Syracuse, NY, 13244, USA.,Department of Chemistry, Syracuse University, Syracuse, NY, 13244, USA.,Interdisciplinary Neuroscience Program, Syracuse University, Syracuse, NY, 13244, USA
| | | | - Amber K Rusnock
- Department of Biology, Syracuse University, Syracuse, NY, 13244, USA
| | - Heidi Hehnly
- Department of Biology, Syracuse University, Syracuse, NY, 13244, USA
| | - Carlos A Castañeda
- Department of Biology, Syracuse University, Syracuse, NY, 13244, USA.,Department of Chemistry, Syracuse University, Syracuse, NY, 13244, USA.,Interdisciplinary Neuroscience Program, Syracuse University, Syracuse, NY, 13244, USA
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230
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Arabidopsis thaliana G3BP Ortholog Rescues Mammalian Stress Granule Phenotype across Kingdoms. Int J Mol Sci 2021; 22:ijms22126287. [PMID: 34208100 PMCID: PMC8230867 DOI: 10.3390/ijms22126287] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 06/08/2021] [Accepted: 06/08/2021] [Indexed: 11/16/2022] Open
Abstract
Stress granules (SGs) are dynamic RNA–protein complexes localized in the cytoplasm that rapidly form under stress conditions and disperse when normal conditions are restored. The formation of SGs depends on the Ras-GAP SH3 domain-binding protein (G3BP). Formations, interactions and functions of plant and human SGs are strikingly similar, suggesting a conserved mechanism. However, functional analyses of plant G3BPs are missing. Thus, members of the Arabidopsis thaliana G3BP (AtG3BP) protein family were investigated in a complementation assay in a human G3BP knock-out cell line. It was shown that two out of seven AtG3BPs were able to complement the function of their human homolog. GFP-AtG3BP fusion proteins co-localized with human SG marker proteins Caprin-1 and eIF4G1 and restored SG formation in G3BP double KO cells. Interaction between AtG3BP-1 and -7 and known human G3BP interaction partners such as Caprin-1 and USP10 was also demonstrated by co-immunoprecipitation. In addition, an RG/RGG domain exchange from Arabidopsis G3BP into the human G3BP background showed the ability for complementation. In summary, our results support a conserved mechanism of SG function over the kingdoms, which will help to further elucidate the biological function of the Arabidopsis G3BP protein family.
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231
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Iyori M, Ogawa R, Emran TB, Tanbo S, Yoshida S. Characterization of the Gene Expression Patterns in the Murine Liver Following Intramuscular Administration of Baculovirus. Gene Expr 2021; 20:147-155. [PMID: 33115550 PMCID: PMC8201657 DOI: 10.3727/105221620x16039045978676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Intramuscular administration of wild-type baculovirus is able to both protect against Plasmodium sporozoite challenge and eliminate liver-stage parasites via a Toll-like receptor 9-independent pathway. To investigate its effector mechanism(s), the gene expression profile in the liver of baculovirus-administered mice was characterized by cDNA microarray analysis. The ingenuity pathway analysis gene ontology module revealed that the major gene subsets induced by baculovirus were immune-related signaling, such as interferon signaling. A total of 40 genes commonly upregulated in a Toll-like receptor 9-independent manner were included as possible candidates for parasite elimination. This gene subset consisted of NT5C3, LOC105246895, BTC, APOL9a/b, G3BP3, SLC6A6, USP25, TRIM14, and PSMB8 as the top 10 candidates according to the special unit. These findings provide new insight into effector molecules responsible for liver-stage parasite killing and, possibly, the development of a new baculovirus-mediated prophylactic and therapeutic biopharmaceutical for malaria.
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Affiliation(s)
- Mitsuhiro Iyori
- *Laboratory of Vaccinology and Applied Immunology, Kanazawa University School of Pharmacy, Kanazawa, Japan
| | - Ryohei Ogawa
- †Department of Radiological Sciences, University of Toyama, Toyama, Japan
| | - Talha Bin Emran
- *Laboratory of Vaccinology and Applied Immunology, Kanazawa University School of Pharmacy, Kanazawa, Japan
| | - Shuta Tanbo
- *Laboratory of Vaccinology and Applied Immunology, Kanazawa University School of Pharmacy, Kanazawa, Japan
| | - Shigeto Yoshida
- *Laboratory of Vaccinology and Applied Immunology, Kanazawa University School of Pharmacy, Kanazawa, Japan
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232
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Marcelo A, Koppenol R, de Almeida LP, Matos CA, Nóbrega C. Stress granules, RNA-binding proteins and polyglutamine diseases: too much aggregation? Cell Death Dis 2021; 12:592. [PMID: 34103467 PMCID: PMC8187637 DOI: 10.1038/s41419-021-03873-8] [Citation(s) in RCA: 76] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 05/25/2021] [Accepted: 05/25/2021] [Indexed: 02/05/2023]
Abstract
Stress 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.
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Affiliation(s)
- Adriana Marcelo
- Algarve Biomedical Center Research Institute (ABC-RI), Faro, Portugal
- PhD Program in Biomedial Sciences, Faculty of Medicine and Biomedical Sciences, University of Algarve, Faro, Portugal
- Centre for Biomedical Research (CBMR), Universidade do Algarve, Faro, Portugal
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal
- Faculty of Medicine and Biomedical Sciences, University of Algarve, Faro, Portugal
| | - Rebekah Koppenol
- Algarve Biomedical Center Research Institute (ABC-RI), Faro, Portugal
- PhD Program in Biomedial Sciences, Faculty of Medicine and Biomedical Sciences, University of Algarve, Faro, Portugal
- Centre for Biomedical Research (CBMR), Universidade do Algarve, Faro, Portugal
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal
- Faculty of Medicine and Biomedical Sciences, University of Algarve, Faro, Portugal
| | - Luís Pereira de Almeida
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal
- Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal
| | - Carlos A Matos
- Algarve Biomedical Center Research Institute (ABC-RI), Faro, Portugal
- Centre for Biomedical Research (CBMR), Universidade do Algarve, Faro, Portugal
- Faculty of Medicine and Biomedical Sciences, University of Algarve, Faro, Portugal
| | - Clévio Nóbrega
- Algarve Biomedical Center Research Institute (ABC-RI), Faro, Portugal.
- Centre for Biomedical Research (CBMR), Universidade do Algarve, Faro, Portugal.
- Faculty of Medicine and Biomedical Sciences, University of Algarve, Faro, Portugal.
- Champalimaud Research Program, Champalimaud Center for the Unknown, Lisbon, Portugal.
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233
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Reversible protein aggregation as cytoprotective mechanism against heat stress. Curr Genet 2021; 67:849-855. [PMID: 34091720 PMCID: PMC8592950 DOI: 10.1007/s00294-021-01191-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 04/24/2021] [Accepted: 04/27/2021] [Indexed: 01/01/2023]
Abstract
Temperature fluctuation is one of the most frequent threats to which organisms are exposed in nature. The activation of gene expression programs that trigger the transcription of heat stress-protective genes is the main cellular response to resist high temperatures. In addition, reversible accumulation and compartmentalization of thermosensitive proteins in high-order molecular assemblies are emerging as critical mechanisms to ensure cellular protection upon heat stress. Here, we summarize representative examples of membrane-less intracellular bodies formed upon heat stress in yeasts and human cells and highlight how protein aggregation can be turned into a cytoprotective mechanism.
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234
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Vu L, Ghosh A, Tran C, Tebung WA, Sidibé H, Garcia-Mansfield K, David-Dirgo V, Sharma R, Pirrotte P, Bowser R, Vande Velde C. Defining the Caprin-1 Interactome in Unstressed and Stressed Conditions. J Proteome Res 2021; 20:3165-3178. [PMID: 33939924 PMCID: PMC9083243 DOI: 10.1021/acs.jproteome.1c00016] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Cytoplasmic stress granules (SGs) are dynamic foci containing translationally arrested mRNA and RNA-binding proteins (RBPs) that form in response to a variety of cellular stressors. It has been debated that SGs may evolve into cytoplasmic inclusions observed in many neurodegenerative diseases. Recent studies have examined the SG proteome by interrogating the interactome of G3BP1. However, it is widely accepted that multiple baits are required to capture the full SG proteome. To gain further insight into the SG proteome, we employed immunoprecipitation coupled with mass spectrometry of endogenous Caprin-1, an RBP implicated in mRNP granules. Overall, we identified 1543 proteins that interact with Caprin-1. Interactors under stressed conditions were primarily annotated to the ribosome, spliceosome, and RNA transport pathways. We validated four Caprin-1 interactors that localized to arsenite-induced SGs: ANKHD1, TALIN-1, GEMIN5, and SNRNP200. We also validated these stress-induced interactions in SH-SY5Y cells and further determined that SNRNP200 also associated with osmotic- and thermal-induced SGs. Finally, we identified SNRNP200 in cytoplasmic aggregates in amyotrophic lateral sclerosis (ALS) spinal cord and motor cortex. Collectively, our findings provide the first description of the Caprin-1 protein interactome, identify novel cytoplasmic SG components, and reveal a SG protein in cytoplasmic aggregates in ALS patient neurons. Proteomic data collected in this study are available via ProteomeXchange with identifier PXD023271.
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Affiliation(s)
- Lucas Vu
- Department of Neurobiology, Barrow Neurological Institute, Phoenix, AZ, USA
| | - Asmita Ghosh
- Department of Neurosciences, Université de Montréal, Montreal, QC, Canada
- CHUM Research Center, Montréal, QC, Canada
| | - Chelsea Tran
- Department of Neurobiology, Barrow Neurological Institute, Phoenix, AZ, USA
- School of Life Sciences, Arizona State University, Tempe, AZ, USA
| | - Walters Aji Tebung
- Department of Neurosciences, Université de Montréal, Montreal, QC, Canada
- CHUM Research Center, Montréal, QC, Canada
| | - Hadjara Sidibé
- Department of Neurosciences, Université de Montréal, Montreal, QC, Canada
- CHUM Research Center, Montréal, QC, Canada
| | - Krystine Garcia-Mansfield
- Collaborative Center for Translational Mass Spectrometry, Translational Genomics Research Institute, Phoenix, AZ, USA
| | - Victoria David-Dirgo
- Collaborative Center for Translational Mass Spectrometry, Translational Genomics Research Institute, Phoenix, AZ, USA
| | - Ritin Sharma
- Collaborative Center for Translational Mass Spectrometry, Translational Genomics Research Institute, Phoenix, AZ, USA
| | - Patrick Pirrotte
- Collaborative Center for Translational Mass Spectrometry, Translational Genomics Research Institute, Phoenix, AZ, USA
| | - Robert Bowser
- Department of Neurobiology, Barrow Neurological Institute, Phoenix, AZ, USA
| | - Christine Vande Velde
- Department of Neurosciences, Université de Montréal, Montreal, QC, Canada
- CHUM Research Center, Montréal, QC, Canada
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235
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RNA Helicase DDX3: A Double-Edged Sword for Viral Replication and Immune Signaling. Microorganisms 2021; 9:microorganisms9061206. [PMID: 34204859 PMCID: PMC8227550 DOI: 10.3390/microorganisms9061206] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Revised: 05/20/2021] [Accepted: 05/21/2021] [Indexed: 12/19/2022] Open
Abstract
DDX3 is a cellular ATP-dependent RNA helicase involved in different aspects of RNA metabolism ranging from transcription to translation and therefore, DDX3 participates in the regulation of key cellular processes including cell cycle progression, apoptosis, cancer and the antiviral immune response leading to type-I interferon production. DDX3 has also been described as an essential cellular factor for the replication of different viruses, including important human threats such HIV-1 or HCV, and different small molecules targeting DDX3 activity have been developed. Indeed, increasing evidence suggests that DDX3 can be considered not only a promising but also a viable target for anticancer and antiviral treatments. In this review, we summarize distinct functional aspects of DDX3 focusing on its participation as a double-edged sword in the host immune response and in the replication cycle of different viruses.
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236
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Andersson S, Romero A, Rodrigues JI, Hua S, Hao X, Jacobson T, Karl V, Becker N, Ashouri A, Rauch S, Nyström T, Liu B, Tamás MJ. Genome-wide imaging screen uncovers molecular determinants of arsenite-induced protein aggregation and toxicity. J Cell Sci 2021; 134:jcs258338. [PMID: 34085697 PMCID: PMC8214759 DOI: 10.1242/jcs.258338] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 05/03/2021] [Indexed: 12/20/2022] Open
Abstract
The toxic metalloid arsenic causes widespread misfolding and aggregation of cellular proteins. How these protein aggregates are formed in vivo, the mechanisms by which they affect cells and how cells prevent their accumulation is not fully understood. To find components involved in these processes, we performed a genome-wide imaging screen and identified Saccharomyces cerevisiae deletion mutants with either enhanced or reduced protein aggregation levels during arsenite exposure. We show that many of the identified factors are crucial to safeguard protein homeostasis (proteostasis) and to protect cells against arsenite toxicity. The hits were enriched for various functions including protein biosynthesis and transcription, and dedicated follow-up experiments highlight the importance of accurate transcriptional and translational control for mitigating protein aggregation and toxicity during arsenite stress. Some of the hits are associated with pathological conditions, suggesting that arsenite-induced protein aggregation may affect disease processes. The broad network of cellular systems that impinge on proteostasis during arsenic stress identified in this current study provides a valuable resource and a framework for further elucidation of the mechanistic details of metalloid toxicity and pathogenesis. This article has an associated First Person interview with the first authors of the paper.
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Affiliation(s)
- Stefanie Andersson
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, SE-405 30 Göteborg, Sweden
| | - Antonia Romero
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, SE-405 30 Göteborg, Sweden
| | - Joana Isabel Rodrigues
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, SE-405 30 Göteborg, Sweden
| | - Sansan Hua
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, SE-405 30 Göteborg, Sweden
| | - Xinxin Hao
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, SE-405 30 Göteborg, Sweden
- Institute of Biomedicine - Department of Microbiology and Immunology, Sahlgrenska Academy, University of Gothenburg, SE-405 30, Göteborg, Sweden
| | - Therese Jacobson
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, SE-405 30 Göteborg, Sweden
| | - Vivien Karl
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, SE-405 30 Göteborg, Sweden
| | - Nathalie Becker
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, SE-405 30 Göteborg, Sweden
| | - Arghavan Ashouri
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, SE-405 30 Göteborg, Sweden
| | - Sebastien Rauch
- Water Environment Technology, Department of Architecture and Civil Engineering, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
| | - Thomas Nyström
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, SE-405 30 Göteborg, Sweden
- Institute of Biomedicine - Department of Microbiology and Immunology, Sahlgrenska Academy, University of Gothenburg, SE-405 30, Göteborg, Sweden
| | - Beidong Liu
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, SE-405 30 Göteborg, Sweden
| | - Markus J. Tamás
- Department of Chemistry and Molecular Biology, University of Gothenburg, Box 462, SE-405 30 Göteborg, Sweden
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237
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Amen T, Kaganovich D. Stress granules inhibit fatty acid oxidation by modulating mitochondrial permeability. Cell Rep 2021; 35:109237. [PMID: 34133922 PMCID: PMC8220302 DOI: 10.1016/j.celrep.2021.109237] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 03/29/2021] [Accepted: 05/18/2021] [Indexed: 12/17/2022] Open
Abstract
The formation of stress granules (SGs) is an essential aspect of the cellular response to many kinds of stress, but its adaptive role is far from clear. SG dysfunction is implicated in aging-onset neurodegenerative diseases, prompting interest in their physiological function. Here, we report that during starvation stress, SGs interact with mitochondria and regulate metabolic remodeling. We show that SG formation leads to a downregulation of fatty acid β-oxidation (FAO) through the modulation of mitochondrial voltage-dependent anion channels (VDACs), which import fatty acids (FAs) into mitochondria. The subsequent decrease in FAO during long-term starvation reduces oxidative damage and rations FAs for longer use. Failure to form SGs, whether caused by the genetic deletion of SG components or an amyotrophic lateral sclerosis (ALS)-associated mutation, translates into an inability to downregulate FAO. Because metabolic dysfunction is a common pathological element of neurodegenerative diseases, including ALS, our findings provide a direction for studying the clinical relevance of SGs. Stress granules inhibit fatty acid oxidation Stress granules regulate VDAC levels Stress granules control mitochondrial permeability to fatty acids Stress granules redirect fatty acids to lipid droplets
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Affiliation(s)
- Triana Amen
- Department of Experimental Neurodegeneration, University Medical Center Goettingen, Goettingen, Germany
| | - Daniel Kaganovich
- 1Base Pharmaceuticals, Boston, MA 02129, USA; Department of Experimental Neurodegeneration, University Medical Center Goettingen, Goettingen, Germany.
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238
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Cambronero-Urena A, Choi S, Choi S, Kim KK, Kim EM. Polyhexamethylene guanidine phosphate, chloromethylisothiazolinone, and particulate matter are dispensable for stress granule formation in human airway epithelial cells. Anim Cells Syst (Seoul) 2021; 25:146-151. [PMID: 34262657 PMCID: PMC8253204 DOI: 10.1080/19768354.2021.1931442] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Environmental risk factors are recognized as threats to public health. Stress granules (SGs) are non-membranous assemblies of mRNAs and proteins expressed in response to various stressors to promote cell survival. In this study, SG formation was examined to confirm the effects of polyhexamethylene guanidine phosphate (PHMG), chloromethylisothiazolinone (CMIT), and particulate matter (PM10) in airway epithelial cells, A549, HPAEpiC, and BEAS-2B cells. SGs were not observed after CMIT, PHMG, and PM10 treatments, as determined by immunofluorescence microscopy. Moreover, there was no change in the phosphorylation of the translation initiation factor eIF2αfollowing treatment with PHMG, CMIT, and PM10. Taken together, our findings might help determine the biological hazards of these materials.
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Affiliation(s)
| | - Sunkyung Choi
- Department of Biochemistry, Chungnam National University, Daejeon, South Korea
| | - Seri Choi
- Department of Predictive Toxicology, Korea Institute of Toxicology, Daejeon, South Korea
| | - Kee K Kim
- Department of Biochemistry, Chungnam National University, Daejeon, South Korea
| | - Eun-Mi Kim
- Department of Predictive Toxicology, Korea Institute of Toxicology, Daejeon, South Korea
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239
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Bai JL, Liu D, Wang R. Self-assembly of Amphiphilic Diblock Copolymers Induced by Liquid-Liquid Phase Separation. CHINESE JOURNAL OF POLYMER SCIENCE 2021. [DOI: 10.1007/s10118-021-2563-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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240
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Tsoi PS, Quan MD, Choi KJ, Dao KM, Ferreon JC, Ferreon ACM. Electrostatic modulation of hnRNPA1 low-complexity domain liquid-liquid phase separation and aggregation. Protein Sci 2021; 30:1408-1417. [PMID: 33982369 DOI: 10.1002/pro.4108] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 05/10/2021] [Accepted: 05/11/2021] [Indexed: 12/12/2022]
Abstract
Membrane-less organelles and RNP granules are enriched in RNA and RNA-binding proteins containing disordered regions. Heterogeneous nuclear ribonucleoprotein A1 (hnRNPA1), a key regulating protein in RNA metabolism, localizes to cytoplasmic RNP granules including stress granules. Dysfunctional nuclear-cytoplasmic transport and dynamic phase separation of hnRNPA1 leads to abnormal amyloid aggregation and neurodegeneration. The intrinsically disordered C-terminal domain (CTD) of hnRNPA1 mediates both dynamic liquid-liquid phase separation (LLPS) and aggregation. While cellular phase separation drives the formation of membrane-less organelles, aggregation within phase-separated compartments has been linked to neurodegenerative diseases. To understand some of the underlying mechanisms behind protein phase separation and LLPS-mediated aggregation, we studied LLPS of hnRNPA1 CTD in conditions that probe protein electrostatics, modulated specifically by varying pH conditions, and protein, salt and RNA concentrations. In the conditions investigated, we observed LLPS to be favored in acidic conditions, and by high protein, salt and RNA concentrations. We also observed that conditions that favor LLPS also enhance protein aggregation and fibrillation, which suggests an aggregation pathway that is LLPS-mediated. The results reported here also suggest that LLPS can play a direct role in facilitating protein aggregation, and that changes in cellular environment that affect protein electrostatics can contribute to the pathological aggregation exhibited in neurodegeneration.
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Affiliation(s)
- Phoebe S Tsoi
- Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, Texas, USA
| | - My Diem Quan
- Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Kyoung-Jae Choi
- Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Khoa M Dao
- Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Josephine C Ferreon
- Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Allan Chris M Ferreon
- Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, Texas, USA
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241
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Malcova I, Senohrabkova L, Novakova L, Hasek J. eIF3a Destabilization and TDP-43 Alter Dynamics of Heat-Induced Stress Granules. Int J Mol Sci 2021; 22:ijms22105164. [PMID: 34068231 PMCID: PMC8153170 DOI: 10.3390/ijms22105164] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 05/04/2021] [Accepted: 05/08/2021] [Indexed: 12/17/2022] Open
Abstract
Stress granules (SGs) are membrane-less assemblies arising upon various stresses in eukaryotic cells. They sequester mRNAs and proteins from stressful conditions and modulate gene expression to enable cells to resume translation and growth after stress relief. SGs containing the translation initiation factor eIF3a/Rpg1 arise in yeast cells upon robust heat shock (HS) at 46 °C only. We demonstrate that the destabilization of Rpg1 within the PCI domain in the Rpg1-3 variant leads to SGs assembly already at moderate HS at 42 °C. These are bona fide SGs arising upon translation arrest containing mRNAs, which are components of the translation machinery, and associating with P-bodies. HS SGs associate with endoplasmatic reticulum and mitochondria and their contact sites ERMES. Although Rpg1-3-labeled SGs arise at a lower temperature, their disassembly is delayed after HS at 46 °C. Remarkably, the delayed disassembly of HS SGs after the robust HS is reversed by TDP-43, which is a human protein connected with amyotrophic lateral sclerosis. TDP-43 colocalizes with HS SGs in yeast cells and facilitates cell regrowth after the stress relief. Based on our results, we propose yeast HS SGs labeled by Rpg1 and its variants as a novel model system to study functions of TDP-43 in stress granules disassembly.
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Affiliation(s)
- Ivana Malcova
- Institute of Microbiology, Czech Academy of Sciences, Videnska 1083, 14220 Prague, Czech Republic; (L.S.); (L.N.); (J.H.)
- Correspondence: ; Tel.: +420-241062769
| | - Lenka Senohrabkova
- Institute of Microbiology, Czech Academy of Sciences, Videnska 1083, 14220 Prague, Czech Republic; (L.S.); (L.N.); (J.H.)
- First Faculty of Medicine, Charles University, Katerinska 42, 12108 Prague, Czech Republic
| | - Lenka Novakova
- Institute of Microbiology, Czech Academy of Sciences, Videnska 1083, 14220 Prague, Czech Republic; (L.S.); (L.N.); (J.H.)
| | - Jiri Hasek
- Institute of Microbiology, Czech Academy of Sciences, Videnska 1083, 14220 Prague, Czech Republic; (L.S.); (L.N.); (J.H.)
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242
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Verma A, Sumi S, Seervi M. Heat shock proteins-driven stress granule dynamics: yet another avenue for cell survival. Apoptosis 2021; 26:371-384. [PMID: 33978921 DOI: 10.1007/s10495-021-01678-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/04/2021] [Indexed: 12/24/2022]
Abstract
Heat shock proteins (HSPs) are evolutionary conserved 'stress-response' proteins that facilitate cell survival against various adverse conditions. HSP-mediated cytoprotection was hitherto reported to occur principally in two ways. Firstly, HSPs interact directly or indirectly with apoptosis signaling components and suppress apoptosis. Secondly, through chaperon activity, HSPs suppress proteotoxicity and maintain protein-homeostasis. Recent studies highlight the interaction of HSPs with cytoplasmic stress granules (SGs). SGs are conserved cytoplasmic mRNPs granules that aid in cell survival under stressful conditions. We primarily aim to describe the distinct cell survival strategy mediated by HSPs as the crucial regulators of SGs assembly and disassembly. Based on the growing evidence, HSPs and associated co-chaperones act as important determinants of SG assembly, composition and dissolution. Under cellular stress, as a 'stress-coping mechanism', the formation of SGs reprograms protein translation machinery and modulates signaling pathways indispensable for cell survival. Besides their role in suppressing apoptosis, HSPs also regulate protein-homeostasis by their chaperone activity as well as by their tight regulation of SG dynamics. The intricate molecular signaling in and around the nexus of HSPs-SGs and its importance in diseases has to be unearthed. These studies have significant implications in the management of chronic diseases such as cancer and neurodegenerative diseases where SGs possess pathological functions.
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Affiliation(s)
- Akanksha Verma
- Department of Biotechnology, All India Institute of Medical Sciences (AIIMS), New Delhi, 110029, India
| | - S Sumi
- Cardiovascular Diseases and Diabetes Biology, Rajiv Gandhi Centre for Biotechnology (RGCB), Thiruvananthapuram, Kerala, India
| | - Mahendra Seervi
- Department of Biotechnology, All India Institute of Medical Sciences (AIIMS), New Delhi, 110029, India.
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243
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Connecting the "dots": RNP granule network in health and disease. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2021; 1868:119058. [PMID: 33989700 DOI: 10.1016/j.bbamcr.2021.119058] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 05/01/2021] [Accepted: 05/07/2021] [Indexed: 12/26/2022]
Abstract
All cells contain ribonucleoprotein (RNP) granules - large membraneless structures composed of RNA and proteins. Recent breakthroughs in RNP granule research have brought a new appreciation of their crucial role in organising virtually all cellular processes. Cells widely exploit the flexible, dynamic nature of RNP granules to adapt to a variety of functional states and the ever-changing environment. Constant exchange of molecules between the different RNP granules connects them into a network. This network controls basal cellular activities and is remodelled to enable efficient stress response. Alterations in RNP granule structure and regulation have been found to lead to fatal human diseases. The interconnectedness of RNP granules suggests that the RNP granule network as a whole becomes affected in disease states such as a representative neurodegenerative disease amyotrophic lateral sclerosis (ALS). In this review, we summarize available evidence on the communication between different RNP granules and on the RNP granule network disruption as a primary ALS pathomechanism.
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244
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Tikhomirova MA, Sheval EV. Formation of Biomolecular Condensates: Regulation of Embryogenesis at the Cellular Level. Russ J Dev Biol 2021. [DOI: 10.1134/s1062360421020077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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245
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Jin X, Cao X, Liu S, Liu B. Functional Roles of Poly(ADP-Ribose) in Stress Granule Formation and Dynamics. Front Cell Dev Biol 2021; 9:671780. [PMID: 33981709 PMCID: PMC8107429 DOI: 10.3389/fcell.2021.671780] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 04/06/2021] [Indexed: 12/03/2022] Open
Abstract
Stress granules (SGs) are highly dynamic cytoplasmic foci formed in response to stress. The formation of SGs is reported to be regulated by diverse post-translational protein modifications (PTMs). Among them, ADP-ribosylation is of emerging interest due to its recently identified roles in SG organization. In this review, we summarized the latest advances on the roles of poly(ADP-ribose) (PAR) in the regulation of SG formation and dynamics, including its function in modulating nucleocytoplasmic trafficking and SG recruitment of SG components, as well as its effects on protein phase separation behavior. Moreover, the functional role of PAR chain diversity on dynamic of SG composition is also introduced. Potential future developments on investigating global ADP-ribosylation networks, individual roles of different PARPs, and interactions between ADP-ribosylation and other PTMs in SGs are also discussed.
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Affiliation(s)
- Xuejiao Jin
- State Key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou, China
| | - Xiuling Cao
- State Key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou, China
| | - Shenkui Liu
- State Key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou, China
| | - Beidong Liu
- State Key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou, China.,Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden.,Faculty of Science, Center for Large-Scale Cell-Based Screening, University of Gothenburg, Gothenburg, Sweden
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246
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Amen T, Kaganovich D. Small Molecule Screen Reveals Joint Regulation of Stress Granule Formation and Lipid Droplet Biogenesis. Front Cell Dev Biol 2021; 8:606111. [PMID: 33972926 PMCID: PMC8105174 DOI: 10.3389/fcell.2020.606111] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 12/21/2020] [Indexed: 01/22/2023] Open
Abstract
Metabolic regulation is a necessary component of all stress response pathways, because all different mechanisms of stress-adaptation place high-energy demands on the cell. Mechanisms that integrate diverse stress response pathways with their metabolic components are therefore of great interest, but few are known. We show that stress granule (SG) formation, a common adaptive response to a variety of stresses, is reciprocally regulated by the pathways inducing lipid droplet accumulation. Inability to upregulate lipid droplets reduces stress granule formation. Stress granule formation in turn drives lipid droplet clustering and fatty acid accumulation. Our findings reveal a novel connection between stress response pathways and new modifiers of stress granule formation.
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Affiliation(s)
- Triana Amen
- Department of Experimental Neurodegeneration, University Medical Center Göttingen, Göttingen, Germany
| | - Daniel Kaganovich
- Department of Experimental Neurodegeneration, University Medical Center Göttingen, Göttingen, Germany.,1Base Pharmaceuticals, Boston, MA, United States
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247
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Shuster SO, Lee JC. Tryptophan Probes of TDP-43 C-Terminal Domain Amyloid Formation. J Phys Chem B 2021; 125:3781-3789. [PMID: 33835818 DOI: 10.1021/acs.jpcb.1c00767] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Aggregated TAR DNA-binding protein 43 (TDP-43) forms the cytoplasmic hallmarks associated with patients suffering from amyotrophic lateral sclerosis and frontotemporal lobar degeneration with ubiquitin. Under normal conditions, TDP-43 is a 414-amino acid protein; however, aggregates are enriched with N-terminal truncations which contain residues 267-414, known as the C-terminal domain of TDP-43 (TDP-43CTD). To gain residue-specific information on the aggregation process of TDP-43CTD, we created three single-Trp containing mutants (W385F/W412F, W334F/W412F, and W334F/W385F) by substituting two of the three native Trp residues with Phe, yielding fluorescent probes at W334, W385, and W412, respectively. Aggregation kinetics, secondary structure, and fibril morphology were compared to the wild-type protein using thioflavin-T fluorescence, Raman spectroscopy, and transmission electron microscopy, respectively. While only W334 is determined to be in the proteinase-K resistant core, all three sites are sensitive reporters of aggregation, revealing site-specific differences. Interestingly, W334 exhibited unusual multistep Trp kinetics, pinpointing a distinctive role for W334 and its nearby region during aggregation. This behavior is retained even upon seeding, suggesting the observed spectral change is related to fibril growth. This work provides new insights into the aggregation mechanism of TDP-43CTD and exemplifies the advantages of Trp as a site-specific environmentally sensitive fluorescent probe.
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Affiliation(s)
- Sydney O Shuster
- Laboratory of Protein Conformation and Dynamics, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Jennifer C Lee
- Laboratory of Protein Conformation and Dynamics, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
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248
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Schnell HM, Jochem M, Micoogullari Y, Riggs CL, Ivanov P, Welsch H, Ravindran R, Anderson P, Robinson LC, Tatchell K, Hanna J. Reg1 and Snf1 regulate stress-induced relocalization of protein phosphatase-1 to cytoplasmic granules. FEBS J 2021; 288:4833-4848. [PMID: 33682330 DOI: 10.1111/febs.15802] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 02/22/2021] [Accepted: 03/03/2021] [Indexed: 11/26/2022]
Abstract
The compartmentalization of cellular function is achieved largely through the existence of membrane-bound organelles. However, recent work suggests a novel mechanism of compartmentalization mediated by membraneless structures that have liquid droplet-like properties and arise through phase separation. Cytoplasmic stress granules (SGs) are the best characterized and are induced by various stressors including arsenite, heat shock, and glucose deprivation. Current models suggest that SGs play an important role in protein homeostasis by mediating reversible translation attenuation. Protein phosphatase-1 (PP1) is a central cellular regulator responsible for most serine/threonine dephosphorylation. Here, we show that upon arsenite stress, PP1's catalytic subunit Glc7 relocalizes to punctate cytoplasmic granules. This altered localization requires PP1's recently described maturation pathway mediated by the multifunctional ATPase Cdc48 and PP1's regulatory subunit Ypi1. Glc7 relocalization is mediated by its regulatory subunit Reg1 and its target Snf1, the AMP-dependent protein kinase. Surprisingly, Glc7 granules are highly specific to arsenite and appear distinct from canonical SGs. Arsenite induces potent translational inhibition, and translational recovery is strongly dependent on Glc7, but independent of Glc7's well-established role in regulating eIF2α. These results suggest a novel form of stress-induced cytoplasmic granule and a new mode of translational control by Glc7.
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Affiliation(s)
- Helena Maria Schnell
- Department of Pathology, Harvard Medical School and Brigham and Women's Hospital, Boston, MA, USA
| | - Marco Jochem
- Department of Pathology, Harvard Medical School and Brigham and Women's Hospital, Boston, MA, USA
| | - Yagmur Micoogullari
- Department of Pathology, Harvard Medical School and Brigham and Women's Hospital, Boston, MA, USA
| | - Claire Louise Riggs
- Department of Rheumatology, Harvard Medical School and Brigham and Women's Hospital, Boston, MA, USA
| | - Pavel Ivanov
- Department of Rheumatology, Harvard Medical School and Brigham and Women's Hospital, Boston, MA, USA
| | - Hendrik Welsch
- Department of Pathology, Harvard Medical School and Brigham and Women's Hospital, Boston, MA, USA
| | - Rini Ravindran
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, LA, USA
| | - Paul Anderson
- Department of Rheumatology, Harvard Medical School and Brigham and Women's Hospital, Boston, MA, USA
| | - Lucy Christina Robinson
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, LA, USA
| | - Kelly Tatchell
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, LA, USA
| | - John Hanna
- Department of Pathology, Harvard Medical School and Brigham and Women's Hospital, Boston, MA, USA
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249
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Di Marco B, Dell'Albani P, D'Antoni S, Spatuzza M, Bonaccorso CM, Musumeci SA, Drago F, Bardoni B, Catania MV. Fragile X mental retardation protein (FMRP) and metabotropic glutamate receptor subtype 5 (mGlu5) control stress granule formation in astrocytes. Neurobiol Dis 2021; 154:105338. [PMID: 33775821 DOI: 10.1016/j.nbd.2021.105338] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 03/12/2021] [Accepted: 03/17/2021] [Indexed: 12/18/2022] Open
Abstract
Fragile X syndrome (FXS) is a common form of intellectual disability and autism caused by the lack of Fragile X Mental Retardation Protein (FMRP), an RNA-binding protein involved in RNA transport and protein synthesis. Upon cellular stress, global protein synthesis is blocked and mRNAs are recruited into stress granules (SGs), together with RNA-binding proteins including FMRP. Activation of group-I metabotropic glutamate (mGlu) receptors stimulates FMRP-mediated mRNA transport and protein synthesis, but their role in SGs formation is unexplored. To this aim, we pre-treated wild type (WT) and Fmr1 knockout (KO) cultured astrocytes with the group-I-mGlu receptor agonist (S)-3,5-Dihydroxyphenylglycine (DHPG) and exposed them to sodium arsenite (NaAsO2), a widely used inducer of SGs formation. In WT cultures the activation of group-I mGlu receptors reduced SGs formation and recruitment of FMRP into SGs, and also attenuated phosphorylation of eIF2α, a key event crucially involved in SGs formation and inhibition of protein synthesis. In contrast, Fmr1 KO astrocytes, which exhibited a lower number of SGs than WT astrocytes, did not respond to agonist stimulation. Interestingly, the mGlu5 receptor negative allosteric modulator (NAM) 2-methyl-6-(phenylethynyl)pyridine (MPEP) antagonized DHPG-mediated SGs reduction in WT and reversed SGs formation in Fmr1 KO cultures. Our findings reveal a novel function of mGlu5 receptor as modulator of SGs formation and open new perspectives for understanding cellular response to stress in FXS pathophysiology.
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Affiliation(s)
- B Di Marco
- Institute for Biomedical Research and Innovation - The National Research Council of Italy (IRIB-CNR), Catania, Italy
| | - P Dell'Albani
- Institute for Biomedical Research and Innovation - The National Research Council of Italy (IRIB-CNR), Catania, Italy
| | - S D'Antoni
- Institute for Biomedical Research and Innovation - The National Research Council of Italy (IRIB-CNR), Catania, Italy
| | - M Spatuzza
- Oasi Research Institute - IRCCS, Troina, Italy
| | | | | | - F Drago
- Department of Biomedical and Biotecnological Sciences, University of Catania, Italy
| | - B Bardoni
- Université Côte d'Azur, Inserm, CNRS UMR7275, Institute of Molecular and Cellular Pharmacology, Valbonne 06560, France
| | - M V Catania
- Institute for Biomedical Research and Innovation - The National Research Council of Italy (IRIB-CNR), Catania, Italy; Oasi Research Institute - IRCCS, Troina, Italy.
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The RNA-Binding Protein Rasputin/G3BP Enhances the Stability and Translation of Its Target mRNAs. Cell Rep 2021; 30:3353-3367.e7. [PMID: 32160542 DOI: 10.1016/j.celrep.2020.02.066] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 01/13/2020] [Accepted: 02/14/2020] [Indexed: 12/14/2022] Open
Abstract
G3BP RNA-binding proteins are important components of stress granules (SGs). Here, we analyze the role of the Drosophila G3BP Rasputin (RIN) in unstressed cells, where RIN is not SG associated. Immunoprecipitation followed by microarray analysis identifies over 550 mRNAs that copurify with RIN. The mRNAs found in SGs are long and translationally silent. In contrast, we find that RIN-bound mRNAs, which encode core components of the transcription, splicing, and translation machinery, are short, stable, and highly translated. We show that RIN is associated with polysomes and provide evidence for a direct role for RIN and its human homologs in stabilizing and upregulating the translation of their target mRNAs. We propose that when cells are stressed, the resulting incorporation of RIN/G3BPs into SGs sequesters them away from their short target mRNAs. This would downregulate the expression of these transcripts, even though they are not incorporated into stress granules.
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