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Lambert-Smith IA, Shephard VK, McAlary L, Yerbury JJ, Saunders DN. High-content analysis of proteostasis capacity in cellular models of amyotrophic lateral sclerosis (ALS). Sci Rep 2024; 14:13844. [PMID: 38879591 PMCID: PMC11180180 DOI: 10.1038/s41598-024-64366-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 06/07/2024] [Indexed: 06/19/2024] Open
Abstract
Disrupted proteome homeostasis (proteostasis) in amyotrophic lateral sclerosis (ALS) has been a major focus of research in the past two decades. However, the proteostasis processes that become disturbed in ALS are not fully understood. Obtaining more detailed knowledge of proteostasis disruption in association with different ALS-causing mutations will improve our understanding of ALS pathophysiology and may identify novel therapeutic targets and strategies for ALS patients. Here we describe the development and use of a novel high-content analysis (HCA) assay to investigate proteostasis disturbances caused by the expression of several ALS-causing gene variants. This assay involves the use of conformationally-destabilised mutants of firefly luciferase (Fluc) to examine protein folding/re-folding capacity in NSC-34 cells expressing ALS-associated mutations in the genes encoding superoxide dismutase-1 (SOD1A4V) and cyclin F (CCNFS621G). We demonstrate that these Fluc isoforms can be used in high-throughput format to report on reductions in the activity of the chaperone network that result from the expression of SOD1A4V, providing multiplexed information at single-cell resolution. In addition to SOD1A4V and CCNFS621G, NSC-34 models of ALS-associated TDP-43, FUS, UBQLN2, OPTN, VCP and VAPB mutants were generated that could be screened using this assay in future work. For ALS-associated mutant proteins that do cause reductions in protein quality control capacity, such as SOD1A4V, this assay has potential to be applied in drug screening studies to identify candidate compounds that can ameliorate this deficiency.
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Affiliation(s)
- Isabella A Lambert-Smith
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, 2522, Australia.
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, 2522, Australia.
| | - Victoria K Shephard
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, 2522, Australia
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Luke McAlary
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, 2522, Australia
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Justin J Yerbury
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, 2522, Australia
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Darren N Saunders
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, 2522, Australia.
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2
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Sontag EM, Morales-Polanco F, Chen JH, McDermott G, Dolan PT, Gestaut D, Le Gros MA, Larabell C, Frydman J. Nuclear and cytoplasmic spatial protein quality control is coordinated by nuclear-vacuolar junctions and perinuclear ESCRT. Nat Cell Biol 2023; 25:699-713. [PMID: 37081164 DOI: 10.1038/s41556-023-01128-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 03/14/2023] [Indexed: 04/22/2023]
Abstract
Effective protein quality control (PQC), essential for cellular health, relies on spatial sequestration of misfolded proteins into defined inclusions. Here we reveal the coordination of nuclear and cytoplasmic spatial PQC. Cytoplasmic misfolded proteins concentrate in a cytoplasmic juxtanuclear quality control compartment, while nuclear misfolded proteins sequester into an intranuclear quality control compartment (INQ). Particle tracking reveals that INQ and the juxtanuclear quality control compartment converge to face each other across the nuclear envelope at a site proximal to the nuclear-vacuolar junction marked by perinuclear ESCRT-II/III protein Chm7. Strikingly, convergence at nuclear-vacuolar junction contacts facilitates VPS4-dependent vacuolar clearance of misfolded cytoplasmic and nuclear proteins, the latter entailing extrusion of nuclear INQ into the vacuole. Finding that nuclear-vacuolar contact sites are cellular hubs of spatial PQC to facilitate vacuolar clearance of nuclear and cytoplasmic inclusions highlights the role of cellular architecture in proteostasis maintenance.
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Affiliation(s)
- Emily M Sontag
- Department of Biology, Stanford University, Stanford, CA, USA.
- Department of Biological Sciences, Marquette University, Milwaukee, WI, USA.
| | | | - Jian-Hua Chen
- Department of Anatomy, School of Medicine, University of California San Francisco, San Francisco, CA, USA
| | - Gerry McDermott
- Department of Anatomy, School of Medicine, University of California San Francisco, San Francisco, CA, USA
| | - Patrick T Dolan
- Department of Biology, Stanford University, Stanford, CA, USA
- Quantitative Virology and Evolution Unit, National Institute of Allergy and Infectious Diseases, Bethesda, MD, USA
| | - Daniel Gestaut
- Department of Biology, Stanford University, Stanford, CA, USA
| | - Mark A Le Gros
- Department of Anatomy, School of Medicine, University of California San Francisco, San Francisco, CA, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Carolyn Larabell
- Department of Anatomy, School of Medicine, University of California San Francisco, San Francisco, CA, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Judith Frydman
- Department of Biology, Stanford University, Stanford, CA, USA.
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3
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Kriachkov V, Ormsby AR, Kusnadi EP, McWilliam HE, Mintern JD, Amarasinghe SL, Ritchie ME, Furic L, Hatters DM. Arginine-rich C9ORF72 ALS proteins stall ribosomes in a manner distinct from a canonical ribosome-associated quality control substrate. J Biol Chem 2022; 299:102774. [PMID: 36481270 PMCID: PMC9830226 DOI: 10.1016/j.jbc.2022.102774] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 11/23/2022] [Accepted: 11/28/2022] [Indexed: 12/12/2022] Open
Abstract
Hexanucleotide expansion mutations in C9ORF72 are a frequent cause of amyotrophic lateral sclerosis. We previously reported that long arginine-rich dipeptide repeats (DPRs), mimicking abnormal proteins expressed from the hexanucleotide expansion, caused translation stalling when expressed in cell culture models. Whether this stalling provides a mechanism of pathogenicity remains to be determined. Here, we explored the molecular features of DPR-induced stalling and examined whether known mechanisms such as ribosome quality control (RQC) regulate translation elongation on sequences that encode arginine-rich DPRs. We demonstrate that arginine-rich DPRs lead to stalling in a length-dependent manner, with lengths longer than 40 repeats invoking severe translation arrest. Mutational screening of 40×Gly-Xxx DPRs shows that stalling is most pronounced when Xxx is a charged amino acid (Arg, Lys, Glu, or Asp). Through a genome-wide knockout screen, we find that genes regulating stalling on polyadenosine mRNA coding for poly-Lys, a canonical RQC substrate, act differently in the case of arginine-rich DPRs. Indeed, these findings point to a limited scope for natural regulatory responses to resolve the arginine-rich DPR stalls, even though the stalls may be sensed, as evidenced by an upregulation of RQC gene expression. These findings therefore implicate arginine-rich DPR-mediated stalled ribosomes as a source of stress and toxicity and may be a crucial component in pathomechanisms.
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Affiliation(s)
- Viacheslav Kriachkov
- Department of Biochemistry and Pharmacology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | - Angelique R. Ormsby
- Department of Biochemistry and Pharmacology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | - Eric P. Kusnadi
- Translational Prostate Cancer Research Laboratory, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia,Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria, Australia
| | - Hamish E.G. McWilliam
- Department of Biochemistry and Pharmacology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia,Department of Microbiology and Immunology, Peter Doherty Institute of Infection and Immunity, The University of Melbourne, Melbourne, Victoria, Australia
| | - Justine D. Mintern
- Department of Biochemistry and Pharmacology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | | | - Matthew E. Ritchie
- Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia
| | - Luc Furic
- Translational Prostate Cancer Research Laboratory, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia,Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria, Australia,Department of Anatomy and Developmental Biology, Monash Biomedicine Discovery Institute Cancer Program, Monash University, Clayton, Victoria, Australia
| | - Danny M. Hatters
- Department of Biochemistry and Pharmacology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia,For correspondence: Danny M. Hatters
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4
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Mier P, Elena-Real CA, Cortés J, Bernadó P, Andrade-Navarro MA. The sequence context in poly-alanine regions: structure, function and conservation. Bioinformatics 2022; 38:4851-4858. [PMID: 36106994 PMCID: PMC9620824 DOI: 10.1093/bioinformatics/btac610] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 07/07/2022] [Accepted: 09/05/2022] [Indexed: 11/24/2022] Open
Abstract
MOTIVATION Poly-alanine (polyA) regions are protein stretches mostly composed of alanines. Despite their abundance in eukaryotic proteomes and their association to nine inherited human diseases, the structural and functional roles exerted by polyA stretches remain poorly understood. In this work we study how the amino acid context in which polyA regions are settled in proteins influences their structure and function. RESULTS We identified glycine and proline as the most abundant amino acids within polyA and in the flanking regions of polyA tracts, in human proteins as well as in 17 additional eukaryotic species. Our analyses indicate that the non-structuring nature of these two amino acids influences the α-helical conformations predicted for polyA, suggesting a relevant role in reducing the inherent aggregation propensity of long polyA. Then, we show how polyA position in protein N-termini relates with their function as transit peptides. PolyA placed just after the initial methionine is often predicted as part of mitochondrial transit peptides, whereas when placed in downstream positions, polyA are part of signal peptides. A few examples from known structures suggest that short polyA can emerge by alanine substitutions in α-helices; but evolution by insertion is observed for longer polyA. Our results showcase the importance of studying the sequence context of homorepeats as a mechanism to shape their structure-function relationships. AVAILABILITY AND IMPLEMENTATION The datasets used and/or analyzed during the current study are available from the corresponding author onreasonable request. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Pablo Mier
- Faculty of Biology, Institute of Organismic and Molecular Evolution, Johannes Gutenberg University Mainz, 55128 Mainz, Germany
| | - Carlos A Elena-Real
- Centre de Biologie Structurale (CBS), Université de Montpellier, INSERM, CNRS, 34090 Montpellier, France
| | - Juan Cortés
- LAAS-CNRS, Université de Toulouse, CNRS, Toulouse, France
| | - Pau Bernadó
- Centre de Biologie Structurale (CBS), Université de Montpellier, INSERM, CNRS, 34090 Montpellier, France
| | - Miguel A Andrade-Navarro
- Faculty of Biology, Institute of Organismic and Molecular Evolution, Johannes Gutenberg University Mainz, 55128 Mainz, Germany
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5
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Ruff KM, Choi YH, Cox D, Ormsby AR, Myung Y, Ascher DB, Radford SE, Pappu RV, Hatters DM. Sequence grammar underlying the unfolding and phase separation of globular proteins. Mol Cell 2022; 82:3193-3208.e8. [PMID: 35853451 PMCID: PMC10846692 DOI: 10.1016/j.molcel.2022.06.024] [Citation(s) in RCA: 48] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 05/05/2022] [Accepted: 06/15/2022] [Indexed: 12/23/2022]
Abstract
Aberrant phase separation of globular proteins is associated with many diseases. Here, we use a model protein system to understand how the unfolded states of globular proteins drive phase separation and the formation of unfolded protein deposits (UPODs). We find that for UPODs to form, the concentrations of unfolded molecules must be above a threshold value. Additionally, unfolded molecules must possess appropriate sequence grammars to drive phase separation. While UPODs recruit molecular chaperones, their compositional profiles are also influenced by synergistic physicochemical interactions governed by the sequence grammars of unfolded proteins and cellular proteins. Overall, the driving forces for phase separation and the compositional profiles of UPODs are governed by the sequence grammars of unfolded proteins. Our studies highlight the need for uncovering the sequence grammars of unfolded proteins that drive UPOD formation and cause gain-of-function interactions whereby proteins are aberrantly recruited into UPODs.
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Affiliation(s)
- Kiersten M Ruff
- Department of Biomedical Engineering, Center for Science & Engineering of Living Systems, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Yoon Hee Choi
- Department of Biochemistry and Pharmacology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Dezerae Cox
- Department of Biochemistry and Pharmacology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Angelique R Ormsby
- Department of Biochemistry and Pharmacology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Yoochan Myung
- Computational Biology and Clinical Informatics, Baker Heart and Diabetes Institute, Melbourne, VIC 3004, Australia; Structural Biology and Bioinformatics, Department of Biochemistry and Pharmacology, The University of Melbourne, Melbourne, VIC 3010, Australia; Systems and Computational Biology, Bio21 Institute, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - David B Ascher
- Computational Biology and Clinical Informatics, Baker Heart and Diabetes Institute, Melbourne, VIC 3004, Australia; Structural Biology and Bioinformatics, Department of Biochemistry and Pharmacology, The University of Melbourne, Melbourne, VIC 3010, Australia; Systems and Computational Biology, Bio21 Institute, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Sheena E Radford
- Astbury Centre for Structural and Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Rohit V Pappu
- Department of Biomedical Engineering, Center for Science & Engineering of Living Systems, Washington University in St. Louis, St. Louis, MO 63130, USA.
| | - Danny M Hatters
- Department of Biochemistry and Pharmacology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, VIC 3010, Australia.
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6
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Lambert-Smith IA, Saunders DN, Yerbury JJ. Progress in biophysics and molecular biology proteostasis impairment and ALS. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2022; 174:3-27. [PMID: 35716729 DOI: 10.1016/j.pbiomolbio.2022.06.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 05/19/2022] [Accepted: 06/09/2022] [Indexed: 12/11/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a rapidly progressive and fatal neurodegenerative disease that results from the loss of both upper and lower motor neurons. It is the most common motor neuron disease and currently has no effective treatment. There is mounting evidence to suggest that disturbances in proteostasis play a significant role in ALS pathogenesis. Proteostasis is the maintenance of the proteome at the right level, conformation and location to allow a cell to perform its intended function. In this review, we present a thorough synthesis of the literature that provides evidence that genetic mutations associated with ALS cause imbalance to a proteome that is vulnerable to such pressure due to its metastable nature. We propose that the mechanism underlying motor neuron death caused by defects in mRNA metabolism and protein degradation pathways converges on proteostasis dysfunction. We propose that the proteostasis network may provide an effective target for therapeutic development in ALS.
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Affiliation(s)
- Isabella A Lambert-Smith
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia; Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, Australia
| | - Darren N Saunders
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia
| | - Justin J Yerbury
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia; Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, Australia.
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7
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Spatial sequestration of misfolded proteins in neurodegenerative diseases. Biochem Soc Trans 2022; 50:759-771. [PMID: 35311889 DOI: 10.1042/bst20210862] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 02/28/2022] [Accepted: 03/02/2022] [Indexed: 12/12/2022]
Abstract
Properly folded, functional proteins are essential for cell health. Cells sustain protein homeostasis, or proteostasis, via protein quality control (PQC) mechanisms. It is currently hypothesized that a breakdown in proteostasis during ageing leads to the accumulation of protein aggregates in the cell and disease. Sequestration of misfolded proteins into PQC compartments represents one branch of the PQC network. In neurodegenerative diseases, certain proteins form abnormal protein deposits. Which PQC compartments house misfolded proteins associated with neurodegenerative diseases is still being investigated. It remains unclear if sequestration of these misfolded proteins is toxic or protective to the cell. Here, we review the current knowledge on various PQC compartments that form in the cell, the kinds of protein aggregates found in neurodegenerative diseases, and what is known about their sequestration. Understanding how protein sequestration occurs can shed light on why aggregates are toxic to the cell and are linked to neurodegenerative diseases like Huntington's, Alzheimer's, and Parkinson's diseases.
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McAlary L, Chew YL, Lum JS, Geraghty NJ, Yerbury JJ, Cashman NR. Amyotrophic Lateral Sclerosis: Proteins, Proteostasis, Prions, and Promises. Front Cell Neurosci 2020; 14:581907. [PMID: 33328890 PMCID: PMC7671971 DOI: 10.3389/fncel.2020.581907] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 09/22/2020] [Indexed: 12/13/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is characterized by the progressive degeneration of the motor neurons that innervate muscle, resulting in gradual paralysis and culminating in the inability to breathe or swallow. This neuronal degeneration occurs in a spatiotemporal manner from a point of onset in the central nervous system (CNS), suggesting that there is a molecule that spreads from cell-to-cell. There is strong evidence that the onset and progression of ALS pathology is a consequence of protein misfolding and aggregation. In line with this, a hallmark pathology of ALS is protein deposition and inclusion formation within motor neurons and surrounding glia of the proteins TAR DNA-binding protein 43, superoxide dismutase-1, or fused in sarcoma. Collectively, the observed protein aggregation, in conjunction with the spatiotemporal spread of symptoms, strongly suggests a prion-like propagation of protein aggregation occurs in ALS. In this review, we discuss the role of protein aggregation in ALS concerning protein homeostasis (proteostasis) mechanisms and prion-like propagation. Furthermore, we examine the experimental models used to investigate these processes, including in vitro assays, cultured cells, invertebrate models, and murine models. Finally, we evaluate the therapeutics that may best prevent the onset or spread of pathology in ALS and discuss what lies on the horizon for treating this currently incurable disease.
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Affiliation(s)
- Luke McAlary
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
- Molecular Horizons and School of Chemistry and Molecular Bioscience, Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW, Australia
| | - Yee Lian Chew
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
- Molecular Horizons and School of Chemistry and Molecular Bioscience, Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW, Australia
| | - Jeremy Stephen Lum
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
- Molecular Horizons and School of Chemistry and Molecular Bioscience, Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW, Australia
| | - Nicholas John Geraghty
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
- Molecular Horizons and School of Chemistry and Molecular Bioscience, Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW, Australia
| | - Justin John Yerbury
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
- Molecular Horizons and School of Chemistry and Molecular Bioscience, Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW, Australia
| | - Neil R. Cashman
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
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9
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Jazurek-Ciesiolka M, Ciesiolka A, Komur AA, Urbanek-Trzeciak MO, Krzyzosiak WJ, Fiszer A. RAN Translation of the Expanded CAG Repeats in the SCA3 Disease Context. J Mol Biol 2020; 432:166699. [PMID: 33157084 DOI: 10.1016/j.jmb.2020.10.033] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 10/26/2020] [Accepted: 10/26/2020] [Indexed: 01/08/2023]
Abstract
Spinocerebellar ataxia type 3 (SCA3) is a progressive neurodegenerative disorder caused by a CAG repeat expansion in the ATXN3 gene encoding the ataxin-3 protein. Despite extensive research the exact pathogenic mechanisms of SCA3 are still not understood in depth. In the present study, to gain insight into the toxicity induced by the expanded CAG repeats in SCA3, we comprehensively investigated repeat-associated non-ATG (RAN) translation in various cellular models expressing translated or non-canonically translated ATXN3 sequences with an increasing number of CAG repeats. We demonstrate that two SCA3 RAN proteins, polyglutamine (polyQ) and polyalanine (polyA), are found only in the case of CAG repeats of pathogenic length. Despite having distinct cellular localization, RAN polyQ and RAN polyA proteins are very often coexpressed in the same cell, impairing nuclear integrity and inducing apoptosis. We provide for the first time mechanistic insights into SCA3 RAN translation indicating that ATXN3 sequences surrounding the repeat region have an impact on SCA3 RAN translation initiation and efficiency. We revealed that RAN translation of polyQ proteins starts at non-cognate codons upstream of the CAG repeats, whereas RAN polyA proteins are likely translated within repeats. Furthermore, integrated stress response activation enhances SCA3 RAN translation. Our findings suggest that the ATXN3 sequence context plays an important role in triggering SCA3 RAN translation and that SCA3 RAN proteins may cause cellular toxicity.
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Affiliation(s)
- Magdalena Jazurek-Ciesiolka
- Department of Medical Biotechnology, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland.
| | - Adam Ciesiolka
- Department of Medical Biotechnology, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Alicja A Komur
- Department of Medical Biotechnology, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Martyna O Urbanek-Trzeciak
- Department of Medical Biotechnology, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Wlodzimierz J Krzyzosiak
- Department of Medical Biotechnology, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Agnieszka Fiszer
- Department of Medical Biotechnology, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland.
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10
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Immiscible inclusion bodies formed by polyglutamine and poly(glycine-alanine) are enriched with distinct proteomes but converge in proteins that are risk factors for disease and involved in protein degradation. PLoS One 2020; 15:e0233247. [PMID: 32857759 PMCID: PMC7455042 DOI: 10.1371/journal.pone.0233247] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 08/13/2020] [Indexed: 12/12/2022] Open
Abstract
Poly(glycine-alanine) (polyGA) is one of the polydipeptides expressed in Frontotemporal Dementia and/or Amyotrophic Lateral Sclerosis 1 caused by C9ORF72 mutations and accumulates as inclusion bodies in the brain of patients. Superficially these inclusions are similar to those formed by polyglutamine (polyQ)-expanded Huntingtin exon 1 (Httex1) in Huntington’s disease. Both have been reported to form an amyloid-like structure suggesting they might aggregate via similar mechanisms and therefore recruit the same repertoire of endogenous proteins. When co-expressed in the same cell, polyGA101 and Httex1(Q97) inclusions adopted immiscible phases suggesting different endogenous proteins would be enriched. Proteomic analyses identified 822 proteins in the inclusions. Only 7 were specific to polyGA and 4 specific to Httex1(Q97). Quantitation demonstrated distinct enrichment patterns for the proteins not specific to each inclusion type (up to ~8-fold normalized to total mass). The proteasome, microtubules, TriC chaperones, and translational machinery were enriched in polyGA aggregates, whereas Dnaj chaperones, nuclear envelope and RNA splicing proteins were enriched in Httex1(Q97) aggregates. Both structures revealed a collection of folding and degradation machinery including proteins in the Httex1(Q97) aggregates that are risk factors for other neurodegenerative diseases involving protein aggregation when mutated, which suggests a convergence point in the pathomechanisms of these diseases.
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11
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San Gil R, Cox D, McAlary L, Berg T, Walker AK, Yerbury JJ, Ooi L, Ecroyd H. Neurodegenerative disease-associated protein aggregates are poor inducers of the heat shock response in neuronal cells. J Cell Sci 2020; 133:jcs.243709. [PMID: 32661089 DOI: 10.1242/jcs.243709] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 06/30/2020] [Indexed: 12/12/2022] Open
Abstract
Protein aggregates that result in inclusion formation are a pathological hallmark common to many neurodegenerative diseases, including amyotrophic lateral sclerosis, Parkinson's disease and Huntington's disease. Under conditions of cellular stress, activation of the heat shock response (HSR) results in an increase in the levels of molecular chaperones and is a first line of cellular defence against inclusion formation. It remains to be established whether neurodegenerative disease-associated proteins and inclusions are themselves capable of inducing an HSR in neuronal cells. To address this, we generated a neuroblastoma cell line that expresses a fluorescent reporter protein under conditions of heat shock transcription factor 1 (HSF1)-mediated HSR induction. We show that the HSR is not induced by exogenous treatment with aggregated forms of recombinant α-synuclein or the G93A mutant of superoxide dismutase-1 (SOD1G93A) nor intracellular expression of SOD1G93A or a pathogenic form of polyglutamine-expanded huntingtin (Htt72Q). These results suggest that pathogenic proteins evade detection or impair induction of the HSR in neuronal cells. A failure of protein aggregation to induce an HSR might contribute to the development of inclusion pathology in neurodegenerative diseases.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Rebecca San Gil
- Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia.,Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, Australia.,Neurodegeneration Pathobiology Laboratory, Queensland Brain Institute, University of Queensland, St Lucia, QLD 4072, Australia
| | - Dezerae Cox
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC 3052, Australia
| | - Luke McAlary
- Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia.,Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, Australia
| | - Tracey Berg
- Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia.,Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, Australia
| | - Adam K Walker
- Neurodegeneration Pathobiology Laboratory, Queensland Brain Institute, University of Queensland, St Lucia, QLD 4072, Australia
| | - Justin J Yerbury
- Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia.,Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, Australia
| | - Lezanne Ooi
- Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia.,Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, Australia
| | - Heath Ecroyd
- Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia .,Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, Australia
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12
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Vonk WIM, Rainbolt TK, Dolan PT, Webb AE, Brunet A, Frydman J. Differentiation Drives Widespread Rewiring of the Neural Stem Cell Chaperone Network. Mol Cell 2020; 78:329-345.e9. [PMID: 32268122 PMCID: PMC7288733 DOI: 10.1016/j.molcel.2020.03.009] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 11/26/2019] [Accepted: 03/08/2020] [Indexed: 12/15/2022]
Abstract
Neural stem and progenitor cells (NSPCs) are critical for continued cellular replacement in the adult brain. Lifelong maintenance of a functional NSPC pool necessitates stringent mechanisms to preserve a pristine proteome. We find that the NSPC chaperone network robustly maintains misfolded protein solubility and stress resilience through high levels of the ATP-dependent chaperonin TRiC/CCT. Strikingly, NSPC differentiation rewires the cellular chaperone network, reducing TRiC/CCT levels and inducing those of the ATP-independent small heat shock proteins (sHSPs). This switches the proteostasis strategy in neural progeny cells to promote sequestration of misfolded proteins into protective inclusions. The chaperone network of NSPCs is more effective than that of differentiated cells, leading to improved management of proteotoxic stress and amyloidogenic proteins. However, NSPC proteostasis is impaired by brain aging. The less efficient chaperone network of differentiated neural progeny may contribute to their enhanced susceptibility to neurodegenerative diseases characterized by aberrant protein misfolding and aggregation.
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Affiliation(s)
| | - T Kelly Rainbolt
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Patrick T Dolan
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Ashley E Webb
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI 02912, USA; Carney Institute for Brain Science, Brown University, Providence, RI 02912, USA; Center on the Biology of Aging, Brown University, Providence, RI 02912, USA
| | - Anne Brunet
- Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Judith Frydman
- Department of Biology, Stanford University, Stanford, CA 94305, USA; Department of Genetics, Stanford University, Stanford, CA 94305, USA; Chan Zuckerberg Biohub, San Francisco, CA 94158, USA.
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13
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Chaudhuri P, Prajapati KP, Anand BG, Dubey K, Kar K. Amyloid cross-seeding raises new dimensions to understanding of amyloidogenesis mechanism. Ageing Res Rev 2019; 56:100937. [PMID: 31430565 DOI: 10.1016/j.arr.2019.100937] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 06/21/2019] [Accepted: 07/23/2019] [Indexed: 12/12/2022]
Abstract
Hallmarks of most of the amyloid pathologies are surprisingly found to be heterocomponent entities such as inclusions and plaques which contain diverse essential proteins and metabolites. Experimental studies have already revealed the occurrence of coaggregation and cross-seeding during amyloid formation of several proteins and peptides, yielding multicomponent assemblies of amyloid nature. Further, research reports on the co-occurrence of more than one type of amyloid-linked pathologies in the same individual suggest the possible cross-talk among the disease related amyloidogenic protein species during their amyloid growth. In this review paper, we have tried to gain more insight into the process of coaggregation and cross-seeding during amyloid aggregation of proteins, particularly focusing on their relevance to the pathogenesis of the protein misfolding diseases. Revelation of amyloid cross-seeding and coaggregation seems to open new dimensions in our mechanistic understanding of amyloidogenesis and such knowledge may possibly inspire better designing of anti-amyloid therapeutics.
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14
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Cox D, Raeburn C, Sui X, Hatters DM. Protein aggregation in cell biology: An aggregomics perspective of health and disease. Semin Cell Dev Biol 2018; 99:40-54. [PMID: 29753879 DOI: 10.1016/j.semcdb.2018.05.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 03/21/2018] [Accepted: 05/04/2018] [Indexed: 01/08/2023]
Abstract
Maintaining protein homeostasis (proteostasis) is essential for cellular health and is governed by a network of quality control machinery comprising over 800 genes. When proteostasis becomes imbalanced, proteins can abnormally aggregate or become mislocalized. Inappropriate protein aggregation and proteostasis imbalance are two of the central pathological features of common neurodegenerative diseases including Alzheimer, Parkinson, Huntington, and motor neuron diseases. How aggregation contributes to the pathogenic mechanisms of disease remains incompletely understood. Here, we integrate some of the key and emerging ideas as to how protein aggregation relates to imbalanced proteostasis with an emphasis on Huntington disease as our area of main expertise. We propose the term "aggregomics" be coined in reference to how aggregation of particular proteins concomitantly influences the spatial organization and protein-protein interactions of the surrounding proteome. Meta-analysis of aggregated interactomes from various published datasets reveals chaperones and RNA-binding proteins are common components across various disease contexts. We conclude with an examination of therapeutic avenues targeting proteostasis mechanisms.
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Affiliation(s)
- Dezerae Cox
- Department of Biochemistry and Molecular Biology, The University of Melbourne, Australia; Bio21 Molecular Science and Biotechnology Institute, Australia
| | - Candice Raeburn
- Department of Biochemistry and Molecular Biology, The University of Melbourne, Australia; Bio21 Molecular Science and Biotechnology Institute, Australia
| | - Xiaojing Sui
- Department of Biochemistry and Molecular Biology, The University of Melbourne, Australia; Bio21 Molecular Science and Biotechnology Institute, Australia
| | - Danny M Hatters
- Department of Biochemistry and Molecular Biology, The University of Melbourne, Australia; Bio21 Molecular Science and Biotechnology Institute, Australia.
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15
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Zeineddine R, Farrawell NE, Lambert-Smith IA, Yerbury JJ. Addition of exogenous SOD1 aggregates causes TDP-43 mislocalisation and aggregation. Cell Stress Chaperones 2017; 22:893-902. [PMID: 28560609 PMCID: PMC5655364 DOI: 10.1007/s12192-017-0804-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Revised: 04/24/2017] [Accepted: 04/28/2017] [Indexed: 12/11/2022] Open
Abstract
ALS is characterised by a focal onset of motor neuron loss, followed by contiguous outward spreading of pathology throughout the nervous system, resulting in paralysis and death generally within a few years after diagnosis. The aberrant release and uptake of toxic proteins including SOD1 and TDP-43 and their subsequent propagation, accumulation and deposition in motor neurons may explain such a pattern of pathology. Previous work has suggested that the internalization of aggregates triggers stress granule formation. Given the close association of stress granules and TDP-43, we wondered whether internalisation of SOD1 aggregates stimulated TDP-43 cytosolic aggregate structures. Addition of recombinant mutant G93A SOD1 aggregates to NSC-34 cells was found to trigger a rapid shift of TDP-43 to the cytoplasm where it was still accumulated after 48 h. In addition, SOD1 aggregates also triggered cleavage of TDP-43 into fragments including a 25 kDa fragment. Collectively, this study suggests a role for protein aggregate uptake in TDP-43 pathology.
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Affiliation(s)
- Rafaa Zeineddine
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia
- School of Biological Sciences, Science Medicine and Health Faculty, University of Wollongong, Wollongong, NSW, Australia
| | - Natalie E Farrawell
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia
- School of Biological Sciences, Science Medicine and Health Faculty, University of Wollongong, Wollongong, NSW, Australia
| | - Isabella A Lambert-Smith
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia
- School of Biological Sciences, Science Medicine and Health Faculty, University of Wollongong, Wollongong, NSW, Australia
| | - Justin J Yerbury
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia.
- School of Biological Sciences, Science Medicine and Health Faculty, University of Wollongong, Wollongong, NSW, Australia.
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16
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San Gil R, Ooi L, Yerbury JJ, Ecroyd H. The heat shock response in neurons and astroglia and its role in neurodegenerative diseases. Mol Neurodegener 2017; 12:65. [PMID: 28923065 PMCID: PMC5604514 DOI: 10.1186/s13024-017-0208-6] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2017] [Accepted: 09/01/2017] [Indexed: 12/13/2022] Open
Abstract
Protein inclusions are a predominant molecular pathology found in numerous neurodegenerative diseases, including amyotrophic lateral sclerosis and Huntington's disease. Protein inclusions form in discrete areas of the brain characteristic to the type of neurodegenerative disease, and coincide with the death of neurons in that region (e.g. spinal cord motor neurons in amyotrophic lateral sclerosis). This suggests that the process of protein misfolding leading to inclusion formation is neurotoxic, and that cell-autonomous and non-cell autonomous mechanisms that maintain protein homeostasis (proteostasis) can, at times, be insufficient to prevent protein inclusion formation in the central nervous system. The heat shock response is a pro-survival pathway induced under conditions of cellular stress that acts to maintain proteostasis through the up-regulation of heat shock proteins, a superfamily of molecular chaperones, other co-chaperones and mitotic regulators. The kinetics and magnitude of the heat shock response varies in a stress- and cell-type dependent manner. It remains to be determined if and/or how the heat shock response is activated in the different cell-types that comprise the central nervous system (e.g. neurons and astroglia) in response to protein misfolding events that precede cellular dysfunctions in neurodegenerative diseases. This is particularly relevant considering emerging evidence demonstrating the non-cell autonomous nature of amyotrophic lateral sclerosis and Huntington's disease (and other neurodegenerative diseases) and the destructive role of astroglia in disease progression. This review highlights the complexity of heat shock response activation and addresses whether neurons and glia sense and respond to protein misfolding and aggregation associated with neurodegenerative diseases, in particular Huntington's disease and amyotrophic lateral sclerosis, by inducing a pro-survival heat shock response.
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Affiliation(s)
- Rebecca San Gil
- Illawarra Health and Medical Research Institute and School of Biological Sciences, University of Wollongong, Northfields Ave, Wollongong, 2522 Australia
| | - Lezanne Ooi
- Illawarra Health and Medical Research Institute and School of Biological Sciences, University of Wollongong, Northfields Ave, Wollongong, 2522 Australia
| | - Justin J. Yerbury
- Illawarra Health and Medical Research Institute and School of Biological Sciences, University of Wollongong, Northfields Ave, Wollongong, 2522 Australia
| | - Heath Ecroyd
- Illawarra Health and Medical Research Institute and School of Biological Sciences, University of Wollongong, Northfields Ave, Wollongong, 2522 Australia
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17
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A thiol probe for measuring unfolded protein load and proteostasis in cells. Nat Commun 2017; 8:474. [PMID: 28883394 PMCID: PMC5589734 DOI: 10.1038/s41467-017-00203-5] [Citation(s) in RCA: 109] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 06/12/2017] [Indexed: 12/13/2022] Open
Abstract
When proteostasis becomes unbalanced, unfolded proteins can accumulate and aggregate. Here we report that the dye, tetraphenylethene maleimide (TPE-MI) can be used to measure cellular unfolded protein load. TPE-MI fluorescence is activated upon labelling free cysteine thiols, normally buried in the core of globular proteins that are exposed upon unfolding. Crucially TPE-MI does not become fluorescent when conjugated to soluble glutathione. We find that TPE-MI fluorescence is enhanced upon reaction with cellular proteomes under conditions promoting accumulation of unfolded proteins. TPE-MI reactivity can be used to track which proteins expose more cysteine residues under stress through proteomic analysis. We show that TPE-MI can report imbalances in proteostasis in induced pluripotent stem cell models of Huntington disease, as well as cells transfected with mutant Huntington exon 1 before the formation of visible aggregates. TPE-MI also detects protein damage following dihydroartemisinin treatment of the malaria parasites Plasmodium falciparum. TPE-MI therefore holds promise as a tool to probe proteostasis mechanisms in disease. Proteostasis is maintained through a number of molecular mechanisms, some of which function to protect the folded state of proteins. Here the authors demonstrate the use of TPE-MI in a fluorigenic dye assay for the quantitation of unfolded proteins that can be used to assess proteostasis on a cellular or proteome scale.
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18
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Moily NS, Ormsby AR, Stojilovic A, Ramdzan YM, Diesch J, Hannan RD, Zajac MS, Hannan AJ, Oshlack A, Hatters DM. Transcriptional profiles for distinct aggregation states of mutant Huntingtin exon 1 protein unmask new Huntington's disease pathways. Mol Cell Neurosci 2017; 83:103-112. [DOI: 10.1016/j.mcn.2017.07.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 06/23/2017] [Accepted: 07/21/2017] [Indexed: 11/16/2022] Open
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19
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Abstract
A healthy proteome is essential for cell survival. Protein misfolding is linked to a rapidly expanding list of human diseases, ranging from neurodegenerative diseases to aging and cancer. Many of these diseases are characterized by the accumulation of misfolded proteins in intra- and extracellular inclusions, such as amyloid plaques. The clear link between protein misfolding and disease highlights the need to better understand the elaborate machinery that manages proteome homeostasis, or proteostasis, in the cell. Proteostasis depends on a network of molecular chaperones and clearance pathways involved in the recognition, refolding, and/or clearance of aberrant proteins. Recent studies reveal that an integral part of the cellular management of misfolded proteins is their spatial sequestration into several defined compartments. Here, we review the properties, function, and formation of these compartments. Spatial sequestration plays a central role in protein quality control and cellular fitness and represents a critical link to the pathogenesis of protein aggregation-linked diseases.
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Affiliation(s)
| | - Rahul S Samant
- Department of Biology, Stanford University, Stanford, California 94305; , ,
| | - Judith Frydman
- Department of Biology, Stanford University, Stanford, California 94305; , ,
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20
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Ciryam P, Lambert-Smith IA, Bean DM, Freer R, Cid F, Tartaglia GG, Saunders DN, Wilson MR, Oliver SG, Morimoto RI, Dobson CM, Vendruscolo M, Favrin G, Yerbury JJ. Spinal motor neuron protein supersaturation patterns are associated with inclusion body formation in ALS. Proc Natl Acad Sci U S A 2017; 114:E3935-E3943. [PMID: 28396410 PMCID: PMC5441770 DOI: 10.1073/pnas.1613854114] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a heterogeneous degenerative motor neuron disease linked to numerous genetic mutations in apparently unrelated proteins. These proteins, including SOD1, TDP-43, and FUS, are highly aggregation-prone and form a variety of intracellular inclusion bodies that are characteristic of different neuropathological subtypes of the disease. Contained within these inclusions are a variety of proteins that do not share obvious characteristics other than coaggregation. However, recent evidence from other neurodegenerative disorders suggests that disease-affected biochemical pathways can be characterized by the presence of proteins that are supersaturated, with cellular concentrations significantly greater than their solubilities. Here, we show that the proteins that form inclusions of mutant SOD1, TDP-43, and FUS are not merely a subset of the native interaction partners of these three proteins, which are themselves supersaturated. To explain the presence of coaggregating proteins in inclusions in the brain and spinal cord, we observe that they have an average supersaturation even greater than the average supersaturation of the native interaction partners in motor neurons, but not when scores are generated from an average of other human tissues. These results suggest that inclusion bodies in various forms of ALS result from a set of proteins that are metastable in motor neurons, and thus prone to aggregation upon a disease-related progressive collapse of protein homeostasis in this specific setting.
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Affiliation(s)
- Prajwal Ciryam
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom;
- Department of Molecular Biosciences, Rice Institute for Biomedical Research, Northwestern University, Evanston, IL 60208-3500
- Department of Medicine, Columbia University College of Physicans & Surgeons, New York, NY 10032-3784
| | - Isabella A Lambert-Smith
- Cambridge Systems Biology Centre, University of Cambridge, Cambridge CB2 1GA, United Kingdom
- Illawarra Health and Medical Research Institute, Wollongong, NSW 2522 Australia
- School of Biological Sciences, Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW 2522 Australia
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, United Kingdom
| | - Daniel M Bean
- Cambridge Systems Biology Centre, University of Cambridge, Cambridge CB2 1GA, United Kingdom
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, United Kingdom
| | - Rosie Freer
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
| | - Fernando Cid
- Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain
- Universitat Pompeu Fabra, 08003 Barcelona, Spain
| | - Gian Gaetano Tartaglia
- Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain
- Universitat Pompeu Fabra, 08003 Barcelona, Spain
- Institucio Catalana de Recerca i Estudis Avançats, 08010 Barcelona, Spain
| | - Darren N Saunders
- Faculty of Medicine, School of Medical Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Mark R Wilson
- Illawarra Health and Medical Research Institute, Wollongong, NSW 2522 Australia
- School of Biological Sciences, Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW 2522 Australia
| | - Stephen G Oliver
- Cambridge Systems Biology Centre, University of Cambridge, Cambridge CB2 1GA, United Kingdom
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, United Kingdom
| | - Richard I Morimoto
- Department of Molecular Biosciences, Rice Institute for Biomedical Research, Northwestern University, Evanston, IL 60208-3500
| | - Christopher M Dobson
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
| | - Michele Vendruscolo
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
| | - Giorgio Favrin
- Cambridge Systems Biology Centre, University of Cambridge, Cambridge CB2 1GA, United Kingdom
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, United Kingdom
| | - Justin J Yerbury
- Illawarra Health and Medical Research Institute, Wollongong, NSW 2522 Australia;
- School of Biological Sciences, Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW 2522 Australia
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21
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Radwan M, Wood RJ, Sui X, Hatters DM. When proteostasis goes bad: Protein aggregation in the cell. IUBMB Life 2017; 69:49-54. [PMID: 28066979 DOI: 10.1002/iub.1597] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 12/09/2016] [Indexed: 12/12/2022]
Abstract
Protein aggregation is a hallmark of the major neurodegenerative diseases including Alzheimer's, Parkinson's, Huntington's and motor neuron and is a symptom of a breakdown in the management of proteome foldedness. Indeed, it is remarkable that under normal conditions cells can keep their proteome in a highly crowded and confined space without uncontrollable aggregation. Proteins pose a particular challenge relative to other classes of biomolecules because upon synthesis they must typically follow a complex folding pathway to reach their functional conformation (native state). Non-native conformations, including the unfolded nascent chain, are highly prone to aberrant interactions, leading to aggregation. Here we review recent advances in knowledge of proteostasis, approaches to monitor proteostasis and the impact that protein aggregation has on biology. We also include discussion of the outstanding challenges. © 2017 IUBMB Life, 69(2):49-54, 2017.
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Affiliation(s)
- Mona Radwan
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, 30 Flemington Road, Melbourne, Victoria, Australia
| | - Rebecca J Wood
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, 30 Flemington Road, Melbourne, Victoria, Australia
| | - Xiaojing Sui
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, 30 Flemington Road, Melbourne, Victoria, Australia
| | - Danny M Hatters
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, 30 Flemington Road, Melbourne, Victoria, Australia
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22
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Büning S, Sharma A, Vachharajani S, Newcombe E, Ormsby A, Gao M, Gnutt D, Vöpel T, Hatters DM, Ebbinghaus S. Conformational dynamics and self-association of intrinsically disordered Huntingtin exon 1 in cells. Phys Chem Chem Phys 2017; 19:10738-10747. [DOI: 10.1039/c6cp08167c] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In-cell temperature jump experiments induce monomer collapse, misfolding and self-association of the Huntingtin exon 1 protein.
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Affiliation(s)
- Steffen Büning
- Department of Physical Chemistry II
- Ruhr-University Bochum
- D-44780 Bochum
- Germany
| | - Abhishek Sharma
- Department of Physical Chemistry II
- Ruhr-University Bochum
- D-44780 Bochum
- Germany
| | | | - Estella Newcombe
- Department of Biochemistry and Molecular Biology & Bio21 Molecular Science and Biotechnology Institute
- University of Melbourne
- Melbourne
- Australia
| | - Angelique Ormsby
- Department of Biochemistry and Molecular Biology & Bio21 Molecular Science and Biotechnology Institute
- University of Melbourne
- Melbourne
- Australia
| | - Mimi Gao
- Department of Physical Chemistry II
- Ruhr-University Bochum
- D-44780 Bochum
- Germany
| | - David Gnutt
- Department of Physical Chemistry II
- Ruhr-University Bochum
- D-44780 Bochum
- Germany
| | - Tobias Vöpel
- Department of Physical Chemistry II
- Ruhr-University Bochum
- D-44780 Bochum
- Germany
| | - Danny M. Hatters
- Department of Biochemistry and Molecular Biology & Bio21 Molecular Science and Biotechnology Institute
- University of Melbourne
- Melbourne
- Australia
| | - Simon Ebbinghaus
- Department of Physical Chemistry II
- Ruhr-University Bochum
- D-44780 Bochum
- Germany
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23
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Chen MZ, Mok SA, Ormsby AR, Muchowski PJ, Hatters DM. N-Terminal Fragments of Huntingtin Longer than Residue 170 form Visible Aggregates Independently to Polyglutamine Expansion. J Huntingtons Dis 2017; 6:79-91. [PMID: 28339398 DOI: 10.3233/jhd-160207] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND A hallmark of Huntington's disease is the progressive aggregation of full length and N-terminal fragments of polyglutamine (polyQ)-expanded Huntingtin (Htt) into intracellular inclusions. The production of N-terminal fragments appears important for enabling pathology and aggregation; and hence the direct expression of a variety of N-terminal fragments are commonly used to model HD in animal and cellular models. OBJECTIVE It remains unclear how the length of the N-terminal fragments relates to polyQ - mediated aggregation. We investigated the fundamental intracellular aggregation process of eight different-length N-terminal fragments of Htt in both short (25Q) and long polyQ (97Q). METHODS N-terminal fragments were fused to fluorescent proteins and transiently expressed in mammalian cell culture models. These included the classic exon 1 fragment (90 amino acids) and longer forms of 105, 117, 171, 513, 536, 552, and 586 amino acids based on wild-type Htt (of 23Q) sequence length nomenclature. RESULTS N-terminal fragments of less than 171 amino acids only formed inclusions in polyQ-expanded form. By contrast the longer fragments formed inclusions irrespective of Q-length, with Q-length playing a negligible role in extent of aggregation. The inclusions could be classified into 3 distinct morphological categories. One type (Type A) was universally associated with polyQ expansions whereas the other two types (Types B and C) formed independently of polyQ length expansion. CONCLUSIONS PolyQ-expansion was only required for fragments of less than 171 amino acids to aggregate. Longer fragments aggregated predominately through a non-polyQ mechanism, involving at least one, and probably more distinct clustering mechanisms.
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Affiliation(s)
- Moore Z Chen
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, VIC, Australia
| | - Sue-Ann Mok
- Department of Neurology, University of California San Francisco, San Francisco, CA, USA
| | - Angelique R Ormsby
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, VIC, Australia
| | | | - Danny M Hatters
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, VIC, Australia
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24
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Yerbury JJ, Ooi L, Dillin A, Saunders DN, Hatters DM, Beart PM, Cashman NR, Wilson MR, Ecroyd H. Walking the tightrope: proteostasis and neurodegenerative disease. J Neurochem 2016; 137:489-505. [DOI: 10.1111/jnc.13575] [Citation(s) in RCA: 146] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Revised: 02/03/2016] [Accepted: 02/04/2016] [Indexed: 02/06/2023]
Affiliation(s)
- Justin J. Yerbury
- Proteostasis and Disease Research Centre; School of Biological Sciences; Faculty of Science, Medicine and Health; University of Wollongong; Wollongong New South Wales Australia
- Illawarra Health and Medical Research Institute; Wollongong; New South Wales Australia
| | - Lezanne Ooi
- Proteostasis and Disease Research Centre; School of Biological Sciences; Faculty of Science, Medicine and Health; University of Wollongong; Wollongong New South Wales Australia
- Illawarra Health and Medical Research Institute; Wollongong; New South Wales Australia
| | - Andrew Dillin
- Department of Molecular and Cell Biology; Li Ka Shing Center for Biomedical and Health Sciences; The University of California; California USA
- Howard Hughes Medical Institute; The University of California; Berkeley California USA
| | - Darren N. Saunders
- School of Medical Sciences; Faculty of Medicine; University of New South Wales; Randwick New South Wales Australia
- The Kinghorn Cancer Centre; Garvan Institute of Medical Research; Darlinghurst New South Wales Australia
| | - Danny M. Hatters
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute; University of Melbourne; Parkville Victoria Australia
| | - Philip M. Beart
- Florey Institute of Neuroscience and Mental Health; University of Melbourne; Parkville Victoria Australia
| | - Neil R. Cashman
- Department of Medicine (Neurology); University of British Columbia and Vancouver Coastal Health Research Institute; Brain Research Centre; University of British Columbia; Vancouver British Columbia Canada
| | - Mark R. Wilson
- Proteostasis and Disease Research Centre; School of Biological Sciences; Faculty of Science, Medicine and Health; University of Wollongong; Wollongong New South Wales Australia
- Illawarra Health and Medical Research Institute; Wollongong; New South Wales Australia
| | - Heath Ecroyd
- Proteostasis and Disease Research Centre; School of Biological Sciences; Faculty of Science, Medicine and Health; University of Wollongong; Wollongong New South Wales Australia
- Illawarra Health and Medical Research Institute; Wollongong; New South Wales Australia
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25
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Polling S, Ormsby AR, Wood RJ, Lee K, Shoubridge C, Hughes JN, Thomas PQ, Griffin MDW, Hill AF, Bowden Q, Böcking T, Hatters DM. Polyalanine expansions drive a shift into α-helical clusters without amyloid-fibril formation. Nat Struct Mol Biol 2015; 22:1008-15. [DOI: 10.1038/nsmb.3127] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2015] [Accepted: 10/20/2015] [Indexed: 12/17/2022]
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26
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Piña FJ, Niwa M. The ER Stress Surveillance (ERSU) pathway regulates daughter cell ER protein aggregate inheritance. eLife 2015; 4. [PMID: 26327697 PMCID: PMC4555637 DOI: 10.7554/elife.06970] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 08/04/2015] [Indexed: 12/11/2022] Open
Abstract
Stress induced by cytoplasmic protein aggregates can have deleterious consequences for the cell, contributing to neurodegeneration and other diseases. Protein aggregates are also formed within the endoplasmic reticulum (ER), although the fate of ER protein aggregates, specifically during cell division, is not well understood. By simultaneous visualization of both the ER itself and ER protein aggregates, we found that ER protein aggregates that induce ER stress are retained in the mother cell by activation of the ER Stress Surveillance (ERSU) pathway, which prevents inheritance of stressed ER. In contrast, under conditions of normal ER inheritance, ER protein aggregates can enter the daughter cell. Thus, whereas cytoplasmic protein aggregates are retained in the mother cell to protect the functional capacity of daughter cells, the fate of ER protein aggregates is determined by whether or not they activate the ERSU pathway to impede transmission of the cortical ER during the cell cycle.
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Affiliation(s)
- Francisco J Piña
- Division of Biological Sciences, Section of Molecular Biology, Univeristy of California, San Diego, San Diego, United States
| | - Maho Niwa
- Division of Biological Sciences, Section of Molecular Biology, Univeristy of California, San Diego, San Diego, United States
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27
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Farrawell NE, Lambert-Smith IA, Warraich ST, Blair IP, Saunders DN, Hatters DM, Yerbury JJ. Distinct partitioning of ALS associated TDP-43, FUS and SOD1 mutants into cellular inclusions. Sci Rep 2015; 5:13416. [PMID: 26293199 PMCID: PMC4544019 DOI: 10.1038/srep13416] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Accepted: 07/31/2015] [Indexed: 12/12/2022] Open
Abstract
Amyotrophic lateral sclerosis is a rapidly progressing neurodegenerative disease associated with protein misfolding and aggregation. Most cases are characterized by TDP-43 positive inclusions, while a minority of familial ALS cases are instead FUS and SOD1 positive respectively. Cells can generate inclusions of variable type including previously characterized aggresomes, IPOD or JUNQ structures depending on the misfolded protein. SOD1 invariably forms JUNQ inclusions but it remains unclear whether other ALS protein aggregates arise as one of these previously described inclusion types or form unique structures. Here we show that FUS variably partitioned to IPOD, JUNQ or alternate structures, contain a mobile fraction, were not microtubule dependent and initially did not contain ubiquitin. TDP-43 inclusions formed in a microtubule independent manner, did not contain a mobile fraction but variably colocalized to JUNQ inclusions and another alternate structure. We conclude that the RNA binding proteins TDP-43 and FUS do not consistently fit the currently characterised inclusion models suggesting that cells have a larger repertoire for generating inclusions than currently thought, and imply that toxicity in ALS does not stem from a particular aggregation process or aggregate structure.
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Affiliation(s)
- Natalie E. Farrawell
- Illawarra Health and Medical Research Institute, Wollongong, NSW 2522 Australia
- Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW 2522 Australia
| | - Isabella A. Lambert-Smith
- Illawarra Health and Medical Research Institute, Wollongong, NSW 2522 Australia
- Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW 2522 Australia
| | - Sadaf T. Warraich
- Australian School of Advanced Medicine, Macquarie University, Sydney, NSW 2109, Australia
| | - Ian P. Blair
- Australian School of Advanced Medicine, Macquarie University, Sydney, NSW 2109, Australia
| | - Darren N. Saunders
- Cancer Division, Garvan Institute of Medical Research, The Kinghorn Cancer Centre, Darlinghurst NSW 2010, Australia
- St Vincent’s Clinical School, UNSW Medicine
| | | | - Justin J. Yerbury
- Illawarra Health and Medical Research Institute, Wollongong, NSW 2522 Australia
- Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW 2522 Australia
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Upadhyay A, Amanullah A, Chhangani D, Mishra R, Prasad A, Mishra A. Mahogunin Ring Finger-1 (MGRN1), a Multifaceted Ubiquitin Ligase: Recent Unraveling of Neurobiological Mechanisms. Mol Neurobiol 2015; 53:4484-96. [PMID: 26255182 DOI: 10.1007/s12035-015-9379-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Accepted: 07/27/2015] [Indexed: 11/29/2022]
Abstract
In healthy cell, inappropriate accumulation of poor or damaged proteins is prevented by cellular quality control system. Autophagy and ubiquitin proteasome system (UPS) provides regular cytoprotection against proteotoxicity induced by abnormal or disruptive proteins. E3 ubiquitin ligases are crucial components in this defense mechanism. Mahogunin Ring Finger-1 (MGRN1), an E3 ubiquitin ligase of the Really Interesting New Gene (RING) finger family, plays a pivotal role in many biological and cellular mechanisms. Previous findings indicate that lack of functions of MGRN1 can cause spongiform neurodegeneration, congenital heart defects, abnormal left-right patterning, and mitochondrial dysfunctions in mice brains. However, the detailed molecular pathomechanism of MGRN1 in cellular functions and diseases is not well known. This article comprehensively represents the molecular nature, characterization, and functions of MGRN1; we also summarize possible beneficiary aspects of this novel E3 ubiquitin ligase. Here, we review recent literature on the role of MGRN1 in the neuro-pathobiological mechanisms, with precise focus on the processes of neurodegeneration, and thereby propose new lines of potential targets for therapeutic intervention.
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Affiliation(s)
- Arun Upadhyay
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Jodhpur, Rajasthan, 342011, India
| | - Ayeman Amanullah
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Jodhpur, Rajasthan, 342011, India
| | - Deepak Chhangani
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Jodhpur, Rajasthan, 342011, India
| | - Ribhav Mishra
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Jodhpur, Rajasthan, 342011, India
| | - Amit Prasad
- School of Basic Sciences, Indian Institute of Technology Mandi, Mandi, Himachal Pradesh, 175005, India
| | - Amit Mishra
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Jodhpur, Rajasthan, 342011, India.
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29
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Abstract
Highly sophisticated mechanisms that modulate protein structure and function, which involve synthesis and degradation, have evolved to maintain cellular homeostasis. Perturbations in these mechanisms can lead to protein dysfunction as well as deleterious cell processes. Therefore in recent years the etiology of a great number of diseases has been attributed to failures in mechanisms that modulate protein structure. Interconnections among metabolic and cell signaling pathways are critical for homeostasis to converge on mechanisms associated with protein folding as well as for the preservation of the native structure of proteins. For instance, imbalances in secretory protein synthesis pathways lead to a condition known as endoplasmic reticulum (ER) stress which elicits the adaptive unfolded protein response (UPR). Therefore, taking this into consideration, a key part of this paper is developed around the protein folding phenomenon, and cellular mechanisms which support this pivotal condition. We provide an overview of chaperone protein function, UPR via, spatial compartmentalization of protein folding, proteasome role, autophagy, as well as the intertwining between these processes. Several diseases are known to have a molecular etiology in the malfunction of mechanisms responsible for protein folding and in the shielding of native structure, phenomena which ultimately lead to misfolded protein accumulation. This review centers on our current knowledge about pathways that modulate protein folding, and cell responses involved in protein homeostasis.
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30
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Lee JA, Yerbury JJ, Farrawell N, Shearer RF, Constantinescu P, Hatters DM, Schroder WA, Suhrbier A, Wilson MR, Saunders DN, Ranson M. SerpinB2 (PAI-2) Modulates Proteostasis via Binding Misfolded Proteins and Promotion of Cytoprotective Inclusion Formation. PLoS One 2015; 10:e0130136. [PMID: 26083412 PMCID: PMC4470917 DOI: 10.1371/journal.pone.0130136] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 05/18/2015] [Indexed: 11/29/2022] Open
Abstract
SerpinB2 (PAI-2), a member of the clade B family of serine protease inhibitors, is one of the most upregulated proteins following cellular stress. Originally described as an inhibitor of urokinase plasminogen activator, its predominant cytoplasmic localisation suggests an intracellular function. SerpinB2 has been reported to display cytoprotective properties in neurons and to interact with intracellular proteins including components of the ubiquitin-proteasome system (UPS). In the current study we explored the potential role of SerpinB2 as a modulator of proteotoxic stress. Initially, we transiently transfected wild-type SerpinB2 and SerpinB2-/- murine embryonic fibroblasts (MEFs) with Huntingtin exon1-polyglutamine (fused C-terminally to mCherry). Inclusion body formation as result of Huntingtin aggregation was evident in the SerpinB2 expressing cells but significantly impaired in the SerpinB2-/- cells, the latter concomitant with loss in cell viability. Importantly, recovery of the wild-type phenotype and cell viability was rescued by retroviral transduction of SerpinB2 expression. SerpinB2 modestly attenuated Huntingtin and amyloid beta fibril formation in vitro and was able to bind preferentially to misfolded proteins. Given the modest chaperone-like activity of SerpinB2 we tested the ability of SerpinB2 to modulate UPS and autophagy activity using a GFP reporter system and autophagy reporter, respectively. Activity of the UPS was reduced and autophagy was dysregulated in SerpinB2-/- compared to wild-type MEFs. Moreover, we observed a non-covalent interaction between ubiquitin and SerpinB2 in cells using GFP-pulldown assays and bimolecular fluorescence complementation. We conclude that SerpinB2 plays an important role in proteostasis as its loss leads to a proteotoxic phenotype associated with an inability to compartmentalize aggregating proteins and a reduced capacity of the UPS.
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Affiliation(s)
- Jodi A. Lee
- School of Biological Sciences, University of Wollongong, Wollongong, NSW, Australia
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
| | - Justin J. Yerbury
- School of Biological Sciences, University of Wollongong, Wollongong, NSW, Australia
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
| | - Natalie Farrawell
- School of Biological Sciences, University of Wollongong, Wollongong, NSW, Australia
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
| | - Robert F. Shearer
- Kinghorn Cancer Centre and Cancer Research Program, Garvan Institute of Medical Research, Sydney, NSW, Australia
- St Vincent’s Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia
| | - Patrick Constantinescu
- School of Biological Sciences, University of Wollongong, Wollongong, NSW, Australia
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
| | - Danny M. Hatters
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Vic., Australia
| | | | - Andreas Suhrbier
- QIMR Berghofer Medical Research Institute, Brisbane, Qld, Australia
| | - Mark R. Wilson
- School of Biological Sciences, University of Wollongong, Wollongong, NSW, Australia
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
| | - Darren N. Saunders
- Kinghorn Cancer Centre and Cancer Research Program, Garvan Institute of Medical Research, Sydney, NSW, Australia
- St Vincent’s Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia
- * E-mail: (DNS); (MR)
| | - Marie Ranson
- School of Biological Sciences, University of Wollongong, Wollongong, NSW, Australia
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
- * E-mail: (DNS); (MR)
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31
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Scotter EL, Chen HJ, Shaw CE. TDP-43 Proteinopathy and ALS: Insights into Disease Mechanisms and Therapeutic Targets. Neurotherapeutics 2015; 12:352-63. [PMID: 25652699 PMCID: PMC4404432 DOI: 10.1007/s13311-015-0338-x] [Citation(s) in RCA: 216] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Therapeutic options for patients with amyotrophic lateral sclerosis (ALS) are currently limited. However, recent studies show that almost all cases of ALS, as well as tau-negative frontotemporal dementia (FTD), share a common neuropathology characterized by the deposition of TAR-DNA binding protein (TDP)-43-positive protein inclusions, offering an attractive target for the design and testing of novel therapeutics. Here we demonstrate how diverse environmental stressors linked to stress granule formation, as well as mutations in genes encoding RNA processing proteins and protein degradation adaptors, initiate ALS pathogenesis via TDP-43. We review the progressive development of TDP-43 proteinopathy from cytoplasmic mislocalization and misfolding through to macroaggregation and the addition of phosphate and ubiquitin moieties. Drawing from cellular and animal studies, we explore the feasibility of therapeutics that act at each point in pathogenesis, from mitigating genetic risk using antisense oligonucleotides to modulating TDP-43 proteinopathy itself using small molecule activators of autophagy, the ubiquitin-proteasome system, or the chaperone network. We present the case that preventing the misfolding of TDP-43 and/or enhancing its clearance represents the most important target for effectively treating ALS and frontotemporal dementia.
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Affiliation(s)
- Emma L. Scotter
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, de Crespigny Park, London, SE5 8AF UK
- Department of Pharmacology, University of Auckland, Auckland, New Zealand
- Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Han-Jou Chen
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, de Crespigny Park, London, SE5 8AF UK
| | - Christopher E. Shaw
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, de Crespigny Park, London, SE5 8AF UK
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32
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Amen T, Kaganovich D. Dynamic droplets: the role of cytoplasmic inclusions in stress, function, and disease. Cell Mol Life Sci 2015; 72:401-415. [PMID: 25283146 PMCID: PMC11113435 DOI: 10.1007/s00018-014-1740-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 09/16/2014] [Accepted: 09/22/2014] [Indexed: 12/12/2022]
Abstract
Neurodegenerative diseases and other proteinopathies constitute a class of several dozen illnesses etiologically linked to pathological protein misfolding and aggregation. Because of this strong association with disease pathology, cell death, and aging, accumulation of proteins in aggregates or aggregation-associated structures (inclusions) has come to be regarded by many as a deleterious process, to be avoided if possible. Recent work has led us to see inclusion structures and disordered aggregate-like protein mixtures (which we call dynamic droplets) in a new light: not necessarily as a result of a pathological breakdown of cellular order, but as an elaborate cellular architecture regulating function and stress response. In this review, we discuss what is currently known about the role of inclusion structures in cellular homeostasis, stress response, toxicity, and disease. We will focus on possible mechanisms of aggregate toxicity, in contrast to the homeostatic function of several inclusion structures.
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Affiliation(s)
- Triana Amen
- Department of Cell and Developmental Biology, Alexander Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem, 91904, Israel
- Alexander Grass Center for Bioengineering, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Daniel Kaganovich
- Department of Cell and Developmental Biology, Alexander Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem, 91904, Israel.
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