1
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Bonavita R, Di Martino R, Cortone G, Prodomo A, Di Gennaro M, Scerra G, Panico V, Nuzzo S, Salvatore M, Williams SV, Vitale F, Caporaso MG, D’Agostino M, Pisani FM, Fleming A, Renna M. A method for the analysis of the oligomerization profile of the Huntington's disease-associated, aggregation-prone mutant huntingtin protein by isopycnic ultracentrifugation. Front Mol Biosci 2024; 11:1420691. [PMID: 38993838 PMCID: PMC11236693 DOI: 10.3389/fmolb.2024.1420691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2024] [Accepted: 05/31/2024] [Indexed: 07/13/2024] Open
Abstract
Conformational diseases, such as Alzheimer's, Parkinson's and Huntington's diseases as well as ataxias and fronto-temporal disorders, are part of common class of neurological disorders characterised by the aggregation and progressive accumulation of mutant proteins which display aberrant conformation. In particular, Huntington's disease (HD) is caused by mutations leading to an abnormal expansion in the polyglutamine (poly-Q) tract of the huntingtin protein (HTT), leading to the formation of inclusion bodies in neurons of affected patients. Furthermore, recent experimental evidence is challenging the conventional view of the disease by revealing the ability of mutant HTT to be transferred between cells by means of extracellular vesicles (EVs), allowing the mutant protein to seed oligomers involving both the mutant and wild type forms of the protein. There is still no successful strategy to treat HD. In addition, the current understanding of the biological processes leading to the oligomerization and aggregation of proteins bearing the poly-Q tract has been derived from studies conducted on isolated poly-Q monomers and oligomers, whose structural properties are still unclear and often inconsistent. Here we describe a standardised biochemical approach to analyse by isopycnic ultracentrifugation the oligomerization of the N-terminal fragment of mutant HTT. The dynamic range of our method allows one to detect large and heterogeneous HTT complexes. Hence, it could be harnessed for the identification of novel molecular determinants responsible for the aggregation and the prion-like spreading properties of HTT in the context of HD. Equally, it provides a tool to test novel small molecules or bioactive compounds designed to inhibit the aggregation of mutant HTT.
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Affiliation(s)
- Raffaella Bonavita
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples “Federico II”, Naples, Italy
- Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
| | - Rosaria Di Martino
- Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
- Institute for Endocrinology and Experimental Oncology “G. Salvatore”, National Research Council, Naples, Italy
| | - Giuseppe Cortone
- Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
| | - Antonello Prodomo
- Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
| | - Mariagrazia Di Gennaro
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples “Federico II”, Naples, Italy
- Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
- Institute for Endocrinology and Experimental Oncology “G. Salvatore”, National Research Council, Naples, Italy
| | - Gianluca Scerra
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples “Federico II”, Naples, Italy
| | - Valentino Panico
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples “Federico II”, Naples, Italy
| | | | | | - Sarah V. Williams
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Fulvia Vitale
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples “Federico II”, Naples, Italy
| | - Maria Gabriella Caporaso
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples “Federico II”, Naples, Italy
| | - Massimo D’Agostino
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples “Federico II”, Naples, Italy
| | - Francesca M. Pisani
- Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
| | - Angeleen Fleming
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Maurizio Renna
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples “Federico II”, Naples, Italy
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
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2
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Haver HN, Wedemeyer M, Butcher E, Peterson FC, Volkman BF, Scaglione KM. Mechanistic Insight into the Suppression of Polyglutamine Aggregation by SRCP1. ACS Chem Biol 2023; 18:549-560. [PMID: 36791332 PMCID: PMC10023506 DOI: 10.1021/acschembio.2c00893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Protein aggregation is a hallmark of the polyglutamine diseases. One potential treatment for these diseases is suppression of polyglutamine aggregation. Previous work identified the cellular slime mold Dictyostelium discoideum as being naturally resistant to polyglutamine aggregation. Further work identified serine-rich chaperone protein 1 (SRCP1) as a protein that is both necessary in Dictyostelium and sufficient in human cells to suppress polyglutamine aggregation. Therefore, understanding how SRCP1 suppresses aggregation may be useful for developing therapeutics for the polyglutamine diseases. Here we utilized a de novo protein modeling approach to generate predictions of SRCP1's structure. Using our best-fit model, we generated mutants that were predicted to alter the stability of SRCP1 and tested these mutants' stability in cells. Using these data, we identified top models of SRCP1's structure that are consistent with the C-terminal region of SRCP1 forming a β-hairpin with a highly dynamic N-terminal region. We next generated a series of peptides that mimic the predicted β-hairpin and validated that they inhibit aggregation of a polyglutamine-expanded mutant huntingtin exon 1 fragment in vitro. To further assess mechanistic details of how SRCP1 inhibits polyglutamine aggregation, we utilized biochemical assays to determine that SRCP1 inhibits secondary nucleation in a manner dependent upon the regions flanking the polyglutamine tract. Finally, to determine if SRCP1 more could generally suppress protein aggregation, we confirmed that it was sufficient to inhibit aggregation of polyglutamine-expanded ataxin-3. Together these studies provide details into the structural and mechanistic basis of the inhibition of protein aggregation by SRCP1.
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Affiliation(s)
- Holly N. Haver
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC, 27710 USA
| | - Michael Wedemeyer
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI, 53226 USA
| | - Erin Butcher
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC, 27710 USA
| | - Francis C. Peterson
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI, 53226 USA
| | - Brian F. Volkman
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI, 53226 USA
| | - K. Matthew Scaglione
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC, 27710 USA
- Department of Neurology, Duke University, Durham, NC, 27710 USA
- Duke Center for Neurodegeneration and Neurotherapeutics, Durham, NC, 27710 USA
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3
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Vieweg S, Mahul-Mellier AL, Ruggeri FS, Riguet N, DeGuire SM, Chiki A, Cendrowska U, Dietler G, Lashuel HA. The Nt17 Domain and its Helical Conformation Regulate the Aggregation, Cellular Properties and Neurotoxicity of Mutant Huntingtin Exon 1. J Mol Biol 2021; 433:167222. [PMID: 34492254 DOI: 10.1016/j.jmb.2021.167222] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 08/25/2021] [Accepted: 08/26/2021] [Indexed: 11/29/2022]
Abstract
Converging evidence points to the N-terminal domain comprising the first 17 amino acids of the Huntingtin protein (Nt17) as a key regulator of its aggregation, cellular properties and toxicity. In this study, we further investigated the interplay between Nt17 and the polyQ domain repeat length in regulating the aggregation and inclusion formation of exon 1 of the Huntingtin protein (Httex1). In addition, we investigated the effect of removing Nt17 or modulating its local structure on the membrane interactions, neuronal uptake, and toxicity of monomeric or fibrillar Httex1. Our results show that the polyQ and Nt17 domains synergistically modulate the aggregation propensity of Httex1 and that the Nt17 domain plays important roles in shaping the surface properties of mutant Httex1 fibrils and regulating their poly-Q-dependent growth, lateral association and neuronal uptake. Removal of Nt17 or disruption of its transient helical conformations slowed the aggregation of monomeric Httex1 in vitro, reduced inclusion formation in cells, enhanced the neuronal uptake and nuclear accumulation of monomeric Httex1 proteins, and was sufficient to prevent cell death induced by Httex1 72Q overexpression. Finally, we demonstrate that the uptake of Httex1 fibrils into primary neurons and the resulting toxicity are strongly influenced by mutations and phosphorylation events that influence the local helical propensity of Nt17. Altogether, our results demonstrate that the Nt17 domain serves as one of the key master regulators of Htt aggregation, internalization, and toxicity and represents an attractive target for inhibiting Htt aggregate formation, inclusion formation, and neuronal toxicity.
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Affiliation(s)
- Sophie Vieweg
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Anne-Laure Mahul-Mellier
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Francesco S Ruggeri
- Laboratory of the Physics of Living Matter, EPFL, 1015 Lausanne, Switzerland
| | - Nathan Riguet
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Sean M DeGuire
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Anass Chiki
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Urszula Cendrowska
- Laboratory of the Physics of Living Matter, EPFL, 1015 Lausanne, Switzerland
| | - Giovanni Dietler
- Laboratory of the Physics of Living Matter, EPFL, 1015 Lausanne, Switzerland
| | - Hilal A Lashuel
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
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4
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Marquette A, Aisenbrey C, Bechinger B. Membrane Interactions Accelerate the Self-Aggregation of Huntingtin Exon 1 Fragments in a Polyglutamine Length-Dependent Manner. Int J Mol Sci 2021; 22:ijms22136725. [PMID: 34201610 PMCID: PMC8268948 DOI: 10.3390/ijms22136725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 06/07/2021] [Accepted: 06/18/2021] [Indexed: 12/04/2022] Open
Abstract
The accumulation of aggregated protein is a typical hallmark of many human neurodegenerative disorders, including polyglutamine-related diseases such as chorea Huntington. Misfolding of the amyloidogenic proteins gives rise to self-assembled complexes and fibres. The huntingtin protein is characterised by a segment of consecutive glutamines which, when exceeding ~ 37 residues, results in the occurrence of the disease. Furthermore, it has also been demonstrated that the 17-residue amino-terminal domain of the protein (htt17), located upstream of this polyglutamine tract, strongly correlates with aggregate formation and pathology. Here, we demonstrate that membrane interactions strongly accelerate the oligomerisation and β-amyloid fibril formation of htt17-polyglutamine segments. By using a combination of biophysical approaches, the kinetics of fibre formation is investigated and found to be strongly dependent on the presence of lipids, the length of the polyQ expansion, and the polypeptide-to-lipid ratio. Finally, the implications for therapeutic approaches are discussed.
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Affiliation(s)
- Arnaud Marquette
- Chemistry Institute UMR7177, University of Strasbourg/CNRS, 67000 Strasbourg, France; (A.M.); (C.A.)
| | - Christopher Aisenbrey
- Chemistry Institute UMR7177, University of Strasbourg/CNRS, 67000 Strasbourg, France; (A.M.); (C.A.)
| | - Burkhard Bechinger
- Chemistry Institute UMR7177, University of Strasbourg/CNRS, 67000 Strasbourg, France; (A.M.); (C.A.)
- Insitut Universitaire de France, 75005 Paris, France
- Correspondence:
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5
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Bonfanti S, Lionetti MC, Fumagalli MR, Chirasani VR, Tiana G, Dokholyan NV, Zapperi S, La Porta CAM. Molecular mechanisms of heterogeneous oligomerization of huntingtin proteins. Sci Rep 2019; 9:7615. [PMID: 31110208 PMCID: PMC6527588 DOI: 10.1038/s41598-019-44151-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 05/07/2019] [Indexed: 11/11/2022] Open
Abstract
There is still no successful strategy to treat Huntington's disease, an inherited autosomal disorder associated with the aggregation of mutated forms of the huntingtin protein containing polyglutamine tracts with more than 36 repeats. Recent experimental evidence is challenging the conventional view of the disease by revealing transcellular transfer of mutated huntingtin proteins which are able to seed oligomers involving wild type forms of the protein. Here we decipher the molecular mechanism of this unconventional heterogeneous oligomerization by performing discrete molecular dynamics simulations. We identify the most probable oligomer conformations and the molecular regions that can be targeted to destabilize them. Our computational findings are complemented experimentally by fluorescence-lifetime imaging microscopy/fluorescence resonance energy transfer (FLIM-FRET) of cells co-transfected with huntingtin proteins containing short and large polyglutamine tracts. Our work clarifies the structural features responsible for heterogeneous huntingtin aggregation with possible implications to contrast the prion-like spreading of Huntington's disease.
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Affiliation(s)
- Silvia Bonfanti
- Center for Complexity and Biosystems, Department of Physics, University of Milan, Via Celoria 16, 20133, Milano, Italy
| | - Maria Chiara Lionetti
- Center for Complexity and Biosystems, Department of Environmental Science and Policy, University of Milano, via Celoria 26, 20133, Milano, Italy
| | - Maria Rita Fumagalli
- Center for Complexity and Biosystems, Department of Environmental Science and Policy, University of Milano, via Celoria 26, 20133, Milano, Italy
| | - Venkat R Chirasani
- Departments of Pharmacology and Biochemistry & Molecular Biology, Penn State College of Medicine, Hershey, PA, 17033, USA
| | - Guido Tiana
- Center for Complexity and Biosystems, Department of Physics, University of Milan, Via Celoria 16, 20133, Milano, Italy
| | - Nikolay V Dokholyan
- Departments of Pharmacology and Biochemistry & Molecular Biology, Penn State College of Medicine, Hershey, PA, 17033, USA
| | - Stefano Zapperi
- Center for Complexity and Biosystems, Department of Physics, University of Milan, Via Celoria 16, 20133, Milano, Italy
- CNR - Consiglio Nazionale delle Ricerche, Istituto di Chimica della Materia Condensata e di Tecnologie per l'Energia, Via R. Cozzi 53, 20125, Milano, Italy
| | - Caterina A M La Porta
- Center for Complexity and Biosystems, Department of Environmental Science and Policy, University of Milano, via Celoria 26, 20133, Milano, Italy.
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6
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Wagner AS, Politi AZ, Ast A, Bravo-Rodriguez K, Baum K, Buntru A, Strempel NU, Brusendorf L, Hänig C, Boeddrich A, Plassmann S, Klockmeier K, Ramirez-Anguita JM, Sanchez-Garcia E, Wolf J, Wanker EE. Self-assembly of Mutant Huntingtin Exon-1 Fragments into Large Complex Fibrillar Structures Involves Nucleated Branching. J Mol Biol 2018; 430:1725-1744. [PMID: 29601786 DOI: 10.1016/j.jmb.2018.03.017] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 03/14/2018] [Accepted: 03/19/2018] [Indexed: 11/18/2022]
Abstract
Huntingtin (HTT) fragments with extended polyglutamine tracts self-assemble into amyloid-like fibrillar aggregates. Elucidating the fibril formation mechanism is critical for understanding Huntington's disease pathology and for developing novel therapeutic strategies. Here, we performed systematic experimental and theoretical studies to examine the self-assembly of an aggregation-prone N-terminal HTT exon-1 fragment with 49 glutamines (Ex1Q49). Using high-resolution imaging techniques such as electron microscopy and atomic force microscopy, we show that Ex1Q49 fragments in cell-free assays spontaneously convert into large, highly complex bundles of amyloid fibrils with multiple ends and fibril branching points. Furthermore, we present experimental evidence that two nucleation mechanisms control spontaneous Ex1Q49 fibrillogenesis: (1) a relatively slow primary fibril-independent nucleation process, which involves the spontaneous formation of aggregation-competent fibrillary structures, and (2) a fast secondary fibril-dependent nucleation process, which involves nucleated branching and promotes the rapid assembly of highly complex fibril bundles with multiple ends. The proposed aggregation mechanism is supported by studies with the small molecule O4, which perturbs early events in the aggregation cascade and delays Ex1Q49 fibril assembly, comprehensive mathematical and computational modeling studies, and seeding experiments with small, preformed fibrillar Ex1Q49 aggregates that promote the assembly of amyloid fibrils. Together, our results suggest that nucleated branching in vitro plays a critical role in the formation of complex fibrillar HTT exon-1 aggregates with multiple ends.
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Affiliation(s)
- Anne S Wagner
- Neuroproteomics, Max Delbrueck Center for Molecular Medicine, Robert-Rössle-Straße 10, 13125 Berlin, Germany
| | - Antonio Z Politi
- Mathematical Modelling of Cellular Processes, Max Delbrueck Center for Molecular Medicine, Robert-Rössle-Straße 10, 13125 Berlin, Germany
| | - Anne Ast
- Neuroproteomics, Max Delbrueck Center for Molecular Medicine, Robert-Rössle-Straße 10, 13125 Berlin, Germany
| | - Kenny Bravo-Rodriguez
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 2, 45470 Mülheim an der Ruhr, Germany; Computational Biochemistry, University Duisburg-Essen, Universitätsstr. 2, 45141 Essen, Germany
| | - Katharina Baum
- Mathematical Modelling of Cellular Processes, Max Delbrueck Center for Molecular Medicine, Robert-Rössle-Straße 10, 13125 Berlin, Germany
| | - Alexander Buntru
- Neuroproteomics, Max Delbrueck Center for Molecular Medicine, Robert-Rössle-Straße 10, 13125 Berlin, Germany
| | - Nadine U Strempel
- Neuroproteomics, Max Delbrueck Center for Molecular Medicine, Robert-Rössle-Straße 10, 13125 Berlin, Germany
| | - Lydia Brusendorf
- Neuroproteomics, Max Delbrueck Center for Molecular Medicine, Robert-Rössle-Straße 10, 13125 Berlin, Germany
| | - Christian Hänig
- Neuroproteomics, Max Delbrueck Center for Molecular Medicine, Robert-Rössle-Straße 10, 13125 Berlin, Germany
| | - Annett Boeddrich
- Neuroproteomics, Max Delbrueck Center for Molecular Medicine, Robert-Rössle-Straße 10, 13125 Berlin, Germany
| | - Stephanie Plassmann
- Neuroproteomics, Max Delbrueck Center for Molecular Medicine, Robert-Rössle-Straße 10, 13125 Berlin, Germany
| | - Konrad Klockmeier
- Neuroproteomics, Max Delbrueck Center for Molecular Medicine, Robert-Rössle-Straße 10, 13125 Berlin, Germany
| | - Juan M Ramirez-Anguita
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 2, 45470 Mülheim an der Ruhr, Germany
| | - Elsa Sanchez-Garcia
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 2, 45470 Mülheim an der Ruhr, Germany; Computational Biochemistry, University Duisburg-Essen, Universitätsstr. 2, 45141 Essen, Germany
| | - Jana Wolf
- Mathematical Modelling of Cellular Processes, Max Delbrueck Center for Molecular Medicine, Robert-Rössle-Straße 10, 13125 Berlin, Germany.
| | - Erich E Wanker
- Neuroproteomics, Max Delbrueck Center for Molecular Medicine, Robert-Rössle-Straße 10, 13125 Berlin, Germany.
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7
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Polyglutamine expansion diseases: More than simple repeats. J Struct Biol 2017; 201:139-154. [PMID: 28928079 DOI: 10.1016/j.jsb.2017.09.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 08/24/2017] [Accepted: 09/15/2017] [Indexed: 12/27/2022]
Abstract
Polyglutamine (polyQ) repeat-containing proteins are widespread in the human proteome but only nine of them are associated with highly incapacitating neurodegenerative disorders. The genetic expansion of the polyQ tract in disease-related proteins triggers a series of events resulting in neurodegeneration. The polyQ tract plays the leading role in the aggregation mechanism, but other elements modulate the aggregation propensity in the context of the full-length proteins, as implied by variations in the length of the polyQ tract required to trigger the onset of a given polyQ disease. Intrinsic features such as the presence of aggregation-prone regions (APRs) outside the polyQ segments and polyQ-flanking sequences, which synergistically participate in the aggregation process, are emerging for several disease-related proteins. The inherent polymorphic structure of polyQ stretches places the polyQ proteins in a central position in protein-protein interaction networks, where interacting partners may additionally shield APRs or reshape the aggregation course. Expansion of the polyQ tract perturbs the cellular homeostasis and contributes to neuronal failure by modulating protein-protein interactions and enhancing toxic oligomerization. Post-translational modifications further regulate self-assembly either by directly altering the intrinsic aggregation propensity of polyQ proteins, by modulating their interaction with different macromolecules or by modifying their withdrawal by the cell quality control machinery. Here we review the recent data on the multifaceted aggregation pathways of disease-related polyQ proteins, focusing on ataxin-3, the protein mutated in Machado-Joseph disease. Further mechanistic understanding of this network of events is crucial for the development of effective therapies for polyQ diseases.
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8
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Vieweg S, Ansaloni A, Wang ZM, Warner JB, Lashuel HA. An Intein-based Strategy for the Production of Tag-free Huntingtin Exon 1 Proteins Enables New Insights into the Polyglutamine Dependence of Httex1 Aggregation and Fibril Formation. J Biol Chem 2016; 291:12074-86. [PMID: 27002149 PMCID: PMC4933259 DOI: 10.1074/jbc.m116.713982] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 03/18/2016] [Indexed: 12/25/2022] Open
Abstract
The first exon of the Huntingtin protein (Httex1) is one of the most actively studied Htt fragments because its overexpression in R6/2 transgenic mice has been shown to recapitulate several key features of Huntington disease. However, the majority of biophysical studies of Httex1 are based on assessing the structure and aggregation of fusion constructs where Httex1 is fused to large proteins, such as glutathione S-transferase, maltose-binding protein, or thioredoxin, or released in solution upon in situ cleavage of these proteins. Herein, we report an intein-based strategy that allows, for the first time, the rapid and efficient production of native tag-free Httex1 with polyQ repeats ranging from 7Q to 49Q. Aggregation studies on these proteins enabled us to identify interesting polyQ-length-dependent effects on Httex1 oligomer and fibril formation that were previously not observed using Httex1 fusion proteins or Httex1 proteins produced by in situ cleavage of fusion proteins. Our studies revealed the inability of Httex1-7Q/15Q to undergo amyloid fibril formation and an inverse correlation between fibril length and polyQ repeat length, suggesting possible polyQ length-dependent differences in the structural properties of the Httex1 aggregates. Altogether, our findings underscore the importance of working with tag-free Httex1 proteins and indicate that model systems based on non-native Httex1 sequences may not accurately reproduce the effect of polyQ repeat length and solution conditions on Httex1 aggregation kinetics and structural properties.
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Affiliation(s)
- Sophie Vieweg
- From the Laboratory of Molecular and Chemical Biology of Neurodegeneration, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland and
| | - Annalisa Ansaloni
- From the Laboratory of Molecular and Chemical Biology of Neurodegeneration, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland and
| | - Zhe-Ming Wang
- From the Laboratory of Molecular and Chemical Biology of Neurodegeneration, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland and
| | - John B Warner
- From the Laboratory of Molecular and Chemical Biology of Neurodegeneration, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland and
| | - Hilal A Lashuel
- From the Laboratory of Molecular and Chemical Biology of Neurodegeneration, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland and Qatar Biomedical Research Institute (QBRI), Hamad bin Khalifa University (HBKU), 5825 Doha, Qatar
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9
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Inayathullah M, Tan A, Jeyaraj R, Lam J, Cho NJ, Liu CW, Manoukian MAC, Ashkan K, Mahmoudi M, Rajadas J. Self-assembly and sequence length dependence on nanofibrils of polyglutamine peptides. Neuropeptides 2016; 57:71-83. [PMID: 26874369 DOI: 10.1016/j.npep.2016.01.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Revised: 01/11/2016] [Accepted: 01/31/2016] [Indexed: 10/22/2022]
Abstract
Huntington's disease (HD) is recognized as a currently incurable, inherited neurodegenerative disorder caused by the accumulation of misfolded polyglutamine (polyQ) peptide aggregates in neuronal cells. Yet, the mechanism by which newly formed polyQ chains interact and assemble into toxic oligomeric structures remains a critical, unresolved issue. In order to shed further light on the matter, our group elected to investigate the folding of polyQ peptides - examining glutamine repeat lengths ranging from 3 to 44 residues. To characterize these aggregates we employed a diverse array of technologies, including: nuclear magnetic resonance; circular dichroism; Fourier transform infrared spectroscopy; fluorescence resonance energy transfer (FRET), and atomic force microscopy. The data we obtained suggest that an increase in the number of glutamine repeats above 14 residues results in disordered loop structures, with different repeat lengths demonstrating unique folding characteristics. This differential folding manifests in the formation of distinct nano-sized fibrils, and on this basis, we postulate the idea of 14 polyQ repeats representing a critical loop length for neurotoxicity - a property that we hope may prove amenable to future therapeutic intervention. Furthermore, FRET measurements on aged assemblages indicate an increase in the end-to-end distance of the peptide with time, most probably due to the intermixing of individual peptide strands within the nanofibril. Further insight into this apparent time-dependent reorganization of aggregated polyQ peptides may influence future disease modeling of polyQ-related proteinopathies, in addition to directing novel clinical innovations.
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Affiliation(s)
- Mohammed Inayathullah
- Biomaterials & Advanced Drug Delivery Laboratory (BioADD), Stanford University School of Medicine, Stanford University, Palo Alto, CA, USA; Bioorganic and Neurochemistry Laboratory, Central Leather Research Institute, Adyar, Chennai, Tamilnadu, India; Cardiovascular Pharmacology Division, Cardiovascular Institute, Stanford University School of Medicine, Stanford University, Palo Alto, CA, USA
| | - Aaron Tan
- Biomaterials & Advanced Drug Delivery Laboratory (BioADD), Stanford University School of Medicine, Stanford University, Palo Alto, CA, USA; UCL Medical School, University College London (UCL), London, UK; University College London Hospitals NHS Foundation Trust, London, UK.
| | - Rebecca Jeyaraj
- UCL Medical School, University College London (UCL), London, UK
| | - James Lam
- UCL Medical School, University College London (UCL), London, UK
| | - Nam-Joon Cho
- Division of Gastroenterology and Hepatology, Stanford University School of Medicine, Stanford University, Palo Alto, CA, USA; School of Materials Science and Engineering, Nanyang Technological University, Singapore
| | - Corey W Liu
- Stanford Magnetic Resonance Laboratory, Stanford University, Palo Alto, CA, USA
| | - Martin A C Manoukian
- Department of Dermatology, Stanford University School of Medicine, Stanford University, Palo Alto, CA, USA
| | - Keyoumars Ashkan
- Department of Neurosurgery, King's College Hospital NHS Foundation Trust, King's College London, London, UK
| | - Morteza Mahmoudi
- Biomaterials & Advanced Drug Delivery Laboratory (BioADD), Stanford University School of Medicine, Stanford University, Palo Alto, CA, USA; Nanotechnology Research Center, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran; Cardiovascular Pharmacology Division, Cardiovascular Institute, Stanford University School of Medicine, Stanford University, Palo Alto, CA, USA
| | - Jayakumar Rajadas
- Biomaterials & Advanced Drug Delivery Laboratory (BioADD), Stanford University School of Medicine, Stanford University, Palo Alto, CA, USA; Cardiovascular Pharmacology Division, Cardiovascular Institute, Stanford University School of Medicine, Stanford University, Palo Alto, CA, USA.
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10
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Arndt JR, Chaibva M, Legleiter J. The emerging role of the first 17 amino acids of huntingtin in Huntington's disease. Biomol Concepts 2016; 6:33-46. [PMID: 25741791 DOI: 10.1515/bmc-2015-0001] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 02/09/2015] [Indexed: 01/01/2023] Open
Abstract
Huntington's disease (HD) is caused by a polyglutamine (polyQ) domain that is expanded beyond a critical threshold near the N-terminus of the huntingtin (htt) protein, directly leading to htt aggregation. While full-length htt is a large (on the order of ∼350 kDa) protein, it is proteolyzed into a variety of N-terminal fragments that accumulate in oligomers, fibrils, and larger aggregates. It is clear that polyQ length is a key determinant of htt aggregation and toxicity. However, the flanking sequences around the polyQ domain, such as the first 17 amino acids on the N terminus (Nt17), influence aggregation, aggregate stability, influence other important biochemical properties of the protein and ultimately its role in pathogenesis. Here, we review the impact of Nt17 on htt aggregation mechanisms and kinetics, structural properties of Nt17 in both monomeric and aggregate forms, the potential role of posttranslational modifications (PTMs) that occur in Nt17 in HD, and the function of Nt17 as a membrane targeting domain.
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11
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Choudhury KR, Bucha S, Baksi S, Mukhopadhyay D, Bhattacharyya NP. Chaperone-like protein HYPK and its interacting partners augment autophagy. Eur J Cell Biol 2016; 95:182-94. [PMID: 27067261 DOI: 10.1016/j.ejcb.2016.03.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 03/24/2016] [Accepted: 03/29/2016] [Indexed: 12/26/2022] Open
Abstract
To decipher the function(s) of HYPK, a huntingtin (HTT)-interacting protein with chaperone-like activity, we had previously identified 36 novel interacting partners of HYPK. Another 13 proteins were known earlier to be associated with HYPK. On the basis of analysis of the interacting partners of HYPK, it has been shown that HYPK may participate in diverse cellular functions relevant to Huntington's disease. In the present study, we identified additional 5 proteins by co-immunoprecipitation and co-localization. As of now we have 54 primary interactors of HYPK. From the database we collected 1026 unique proteins (secondary interactors) interacting with these 54 primary HYPK interacting partners. We observed that 10 primary and 91 secondary interacting proteins of HYPK are associated with two types of autophagy processes. We next tested the hypothesis that the hub, HYPK, might itself be involved in autophagy. Using mouse striatal STHdh(Q7)/Hdh(Q7) cell lines, we observed that over expression of HYPK significantly increased background cellular autophagy, while knock down of endogenous HYPK decreased the autophagy level as detected by altered LC3I conversion, BECN1 expression, cleavage of GFP from LC3-GFP, ATG5-ATG12 conjugate formation and expression of transcription factors like Tfeb, Srebp2 and Zkscan3. This result shows that HYPK, possibly with its interacting partners, induces autophagy. We further observed that N-terminal mutant HTT reduced the cellular levels of LC3II and BECN1, which could be recovered significantly upon over expression of HYPK in these cells. This result further confirms that HYPK could also be involved in clearing mutant HTT aggregates by augmenting autophagy pathway.
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Affiliation(s)
- Kamalika Roy Choudhury
- Crystallography and Molecular Biology Division, Saha Institute of Nuclear Physics, 1/AF, Bidhan Nagar, Kolkata 700 064, India.
| | - Sudha Bucha
- Crystallography and Molecular Biology Division, Saha Institute of Nuclear Physics, 1/AF, Bidhan Nagar, Kolkata 700 064, India.
| | - Shounak Baksi
- Crystallography and Molecular Biology Division, Saha Institute of Nuclear Physics, 1/AF, Bidhan Nagar, Kolkata 700 064, India.
| | - Debashis Mukhopadhyay
- Crystallography and Molecular Biology Division, Saha Institute of Nuclear Physics, 1/AF, Bidhan Nagar, Kolkata 700 064, India.
| | - Nitai P Bhattacharyya
- Crystallography and Molecular Biology Division, Saha Institute of Nuclear Physics, 1/AF, Bidhan Nagar, Kolkata 700 064, India.
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12
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Ho CS, Khadka NK, She F, Cai J, Pan J. Polyglutamine aggregates impair lipid membrane integrity and enhance lipid membrane rigidity. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:661-70. [PMID: 26806158 DOI: 10.1016/j.bbamem.2016.01.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 01/08/2016] [Accepted: 01/20/2016] [Indexed: 10/22/2022]
Abstract
Lipid membranes are suggested as the primary target of amyloid aggregates. We study aggregates formed by a polyglutamine (polyQ) peptide, and their disruptive effect on lipid membranes. Using solution atomic force microscopy (AFM), we observe polyQ oligomers coexisting with short fibrils, which have a twisted morphology that likely corresponds to two intertwined oligomer strings. Fourier transform infrared spectroscopy reveals that the content of β-sheet enriched aggregates increases with incubation time. Using fluorescence microscopy, we find that exposure to polyQ aggregates results in deflated morphology of giant unilamellar vesicles. PolyQ aggregates induced membrane disruption is further substantiated by time-dependent calcein leakage from the interior to the exterior of lipid vesicles. Detailed structural and mechanical perturbations of lipid membranes are revealed by solution AFM. We find that membrane disruption by polyQ aggregates proceeds by a two-step process, involving partial and full disruption. In addition to height contrast, the resulting partially and fully disrupted bilayers have distinct rigidity and adhesion force properties compared to the intact bilayer. Specifically, the bilayer rigidity increases as the intact bilayer becomes partially and fully disrupted. Surprisingly, the adhesion force first decreases and then increases during the disruption process. By resolving individual fibrils deposited on bilayer surface, we show that both the length and the number of fibrils can increase with incubation time. Our results highlight that membrane disruption could be the molecular basis of polyQ aggregates induced cytotoxicity.
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Affiliation(s)
- Chian Sing Ho
- Department of Physics, University of South Florida, Tampa, FL 33620, United States
| | - Nawal K Khadka
- Department of Physics, University of South Florida, Tampa, FL 33620, United States
| | - Fengyu She
- Department of Chemistry, University of South Florida, Tampa, FL 33620, United States
| | - Jianfeng Cai
- Department of Chemistry, University of South Florida, Tampa, FL 33620, United States
| | - Jianjun Pan
- Department of Physics, University of South Florida, Tampa, FL 33620, United States.
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13
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Yuan D, Shi J, Du X, Zhou N, Xu B. Supramolecular Glycosylation Accelerates Proteolytic Degradation of Peptide Nanofibrils. J Am Chem Soc 2015; 137:10092-5. [PMID: 26237170 PMCID: PMC4941208 DOI: 10.1021/jacs.5b05888] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
![]()
Despite
the recent consensus that the oligomers of amyloid peptides
or aberrant proteins are cytotoxic species, there is still a need
for an effective way to eliminate the oligomers. Based on the fact
that normal proteins are more glycosylated than pathogenic proteins,
we show that a conjugate of nucleobase, peptide, and saccharide binds
to peptides from molecular nanofibrils and accelerates the proteolytic
degradation of the molecular nanofibrils. As the first example of
the use of supramolecular glycosylation to dissociate molecular nanofibrils
and to accelerate the degradation of peptide aggregates, this work
illustrates a new method that ultimately may lead to an effective
approach for degrading cytotoxic oligomers of peptides or aberrant
proteins.
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Affiliation(s)
- Dan Yuan
- Department of Chemistry, Brandeis University, 415 South Street, Waltham, Massachusetts 02454, United States
| | - Junfeng Shi
- Department of Chemistry, Brandeis University, 415 South Street, Waltham, Massachusetts 02454, United States
| | - Xuewen Du
- Department of Chemistry, Brandeis University, 415 South Street, Waltham, Massachusetts 02454, United States
| | - Ning Zhou
- Department of Chemistry, Brandeis University, 415 South Street, Waltham, Massachusetts 02454, United States
| | - Bing Xu
- Department of Chemistry, Brandeis University, 415 South Street, Waltham, Massachusetts 02454, United States
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14
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Huang F, Zhang L, Long Z, Chen Z, Hou X, Wang C, Peng H, Wang J, Li J, Duan R, Xia K, Chuang DM, Tang B, Jiang H. miR-25 alleviates polyQ-mediated cytotoxicity by silencing ATXN3. FEBS Lett 2014; 588:4791-8. [PMID: 25451224 PMCID: PMC6370487 DOI: 10.1016/j.febslet.2014.11.013] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2014] [Revised: 10/29/2014] [Accepted: 11/11/2014] [Indexed: 01/28/2023]
Abstract
MicroRNAs (miRNAs) have been reported to play significant roles in the pathogenesis of various polyQ diseases. This study aims to investigate the regulation of ATXN3 gene expression by miRNA. We found that miR-25 reduced both wild-type and polyQ-expanded mutant ataxin-3 protein levels by interacting with the 3'UTR of ATXN3 mRNA. miR-25 also increased cell viability, decreased early apoptosis, and downregulated the accumulation of mutant ataxin-3 protein aggregates in SCA3/MJD cells. These novel results shed light on the potential role of miR-25 in the pathogenesis of SCA3/MJD, and provide a possible therapeutic intervention for this disorder.
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Affiliation(s)
- Fengzhen Huang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, PR China; Department of Neurology & Institute of Translational Medicine at University of South China, The First People's Hospital of Chenzhou, Chenzhou, PR China
| | - Li Zhang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, PR China
| | - Zhe Long
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, PR China
| | - Zhao Chen
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, PR China
| | - Xuan Hou
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, PR China
| | - Chunrong Wang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, PR China
| | - Huirong Peng
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, PR China
| | - Junling Wang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, PR China
| | - Jiada Li
- State Key Laboratory of Medical Genetics of China, Central South University, Changsha, Hunan 410078, PR China
| | - Ranhui Duan
- State Key Laboratory of Medical Genetics of China, Central South University, Changsha, Hunan 410078, PR China
| | - Kun Xia
- State Key Laboratory of Medical Genetics of China, Central South University, Changsha, Hunan 410078, PR China
| | - De-Maw Chuang
- Molecular Neurobiology Section, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Beisha Tang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, PR China; State Key Laboratory of Medical Genetics of China, Central South University, Changsha, Hunan 410078, PR China; Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, Hunan 410008, PR China
| | - Hong Jiang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, PR China; State Key Laboratory of Medical Genetics of China, Central South University, Changsha, Hunan 410078, PR China; Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, Hunan 410008, PR China.
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15
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Huynen C, Willet N, Buell AK, Duwez AS, Jerôme C, Dumoulin M. Influence of the protein context on the polyglutamine length-dependent elongation of amyloid fibrils. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2014; 1854:239-48. [PMID: 25489872 DOI: 10.1016/j.bbapap.2014.12.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Revised: 11/20/2014] [Accepted: 12/01/2014] [Indexed: 12/24/2022]
Abstract
Polyglutamine (polyQ) diseases, including Huntington's disease, are neurodegenerative disorders associated with the abnormal expansion of a polyQ tract within nine proteins. The polyQ expansion is thought to be a major determinant in the development of neurotoxicity, triggering protein aggregation into amyloid fibrils, although non-polyQ regions play a modulating role. In this work, we investigate the relative importance of the polyQ length, its location within a host protein, and the conformational state of the latter in the amyloid fibril elongation. Model polyQ proteins made of the β-lactamase BlaP containing up to 79Q inserted at two different positions, and quartz crystal microbalance and atomic force microscopy were used for this purpose. We demonstrate that, independently of the polyQ tract location and the conformational state of the host protein, the relative elongation rate of fibrils increases linearly with the polyQ length. The slope of the linear fit is similar for both sets of chimeras (i.e., the elongation rate increases by ~1.9% for each additional glutamine), and is also similar to that previously observed for polyQ peptides. The elongation rate is, however, strongly influenced by the location of the polyQ tract within BlaP and the conformational state of BlaP. Moreover, comparison of our results with those previously reported for aggregation in solution indicates that these two parameters also modulate the ability of BlaP-polyQ chimeras to form the aggregation nucleus. Altogether our results suggest that non-polyQ regions are valuable targets in order to interfere with the process of amyloid fibril formation associated with polyQ diseases.
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Affiliation(s)
- Céline Huynen
- Laboratory of Enzymology and Protein Folding, Centre for Protein Engineering, University of Liege, Liege, Belgium
| | - Nicolas Willet
- Nanochemistry and Molecular Systems, Department of Chemistry, University of Liege, Liege, Belgium
| | - Alexander K Buell
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Anne-Sophie Duwez
- Nanochemistry and Molecular Systems, Department of Chemistry, University of Liege, Liege, Belgium
| | - Christine Jerôme
- Center for Education and Research on Macromolecules (CERM), Department of Chemistry, University of Liege, Liege, Belgium
| | - Mireille Dumoulin
- Laboratory of Enzymology and Protein Folding, Centre for Protein Engineering, University of Liege, Liege, Belgium.
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16
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Chaperone protein HYPK interacts with the first 17 amino acid region of Huntingtin and modulates mutant HTT-mediated aggregation and cytotoxicity. Biochem Biophys Res Commun 2014; 456:66-73. [PMID: 25446099 DOI: 10.1016/j.bbrc.2014.11.035] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 11/14/2014] [Indexed: 11/22/2022]
Abstract
Huntington's disease is a polyglutamine expansion disorder, characterized by mutant HTT-mediated aggregate formation and cytotoxicity. Many reports suggests roles of N-terminal 17 amino acid domain of HTT (HTT-N17) towards subcellular localization, aggregate formation and subsequent pathogenicity induced by N-terminal HTT harboring polyQ stretch in pathogenic range. HYPK is a HTT-interacting chaperone which can reduce N-terminal mutant HTT-mediated aggregate formation and cytotoxicity in neuronal cell lines. However, how HYPK interacts with N-terminal fragment of HTT remained unknown. Here we report that specific interaction of HYPK with HTT-N17 is crucial for the chaperone activity of HYPK. Deletion of HTT-N17 leads to formation of tinier, SDS-soluble nuclear aggregates formed by N-terminal mutant HTT. The increased cytotoxicity imparted by these tiny aggregates might be contributed due to loss of interaction with HYPK.
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17
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Vilasi S, Carrotta R, Mangione MR, Campanella C, Librizzi F, Randazzo L, Martorana V, Marino Gammazza A, Ortore MG, Vilasi A, Pocsfalvi G, Burgio G, Corona D, Palumbo Piccionello A, Zummo G, Bulone D, Conway de Macario E, Macario AJL, San Biagio PL, Cappello F. Human Hsp60 with its mitochondrial import signal occurs in solution as heptamers and tetradecamers remarkably stable over a wide range of concentrations. PLoS One 2014; 9:e97657. [PMID: 24830947 PMCID: PMC4022648 DOI: 10.1371/journal.pone.0097657] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 04/21/2014] [Indexed: 11/23/2022] Open
Abstract
It has been established that Hsp60 can accumulate in the cytosol in various pathological conditions, including cancer and chronic inflammatory diseases. Part or all of the cytosolic Hsp60 could be naïve, namely, bear the mitochondrial import signal (MIS), but neither the structure nor the in solution oligomeric organization of this cytosolic molecule has still been elucidated. Here we present a detailed study of the structure and self-organization of naïve cytosolic Hsp60 in solution. Results were obtained by different biophysical methods (light and X ray scattering, single molecule spectroscopy and hydrodynamics) that all together allowed us to assay a wide range of concentrations of Hsp60. We found that Naïve Hsp60 in aqueous solution is assembled in very stable heptamers and tetradecamers at all concentrations assayed, without any trace of monomer presence.
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Affiliation(s)
- Silvia Vilasi
- Institute of Biophysics, National Research Council, Palermo, Italy
| | - Rita Carrotta
- Institute of Biophysics, National Research Council, Palermo, Italy
| | | | - Claudia Campanella
- Department of Experimental Biomedicine and Clinical Neurosciences, University of Palermo, Palermo, Italy
- Euro-Mediterranean Institute of Science and Technology, Palermo, Italy
| | - Fabio Librizzi
- Institute of Biophysics, National Research Council, Palermo, Italy
| | | | | | - Antonella Marino Gammazza
- Department of Experimental Biomedicine and Clinical Neurosciences, University of Palermo, Palermo, Italy
- Euro-Mediterranean Institute of Science and Technology, Palermo, Italy
| | - Maria Grazia Ortore
- Department of Life and Environmental Sciences and National Interuniversity Consortium for the Physical Sciences of Matter, Marche Polytechnic University, Ancona, Italy
| | - Annalisa Vilasi
- Institute of Biosciences and Bioresources, National Research Council, Napoli, Italy
| | - Gabriella Pocsfalvi
- Institute of Biosciences and Bioresources, National Research Council, Napoli, Italy
| | - Giosalba Burgio
- Department of biological chemical and pharmaceutical sciences and technologies, University of Palermo, Palermo, Italy
| | - Davide Corona
- Department of biological chemical and pharmaceutical sciences and technologies, University of Palermo, Palermo, Italy
| | - Antonio Palumbo Piccionello
- Institute of Biophysics, National Research Council, Palermo, Italy
- Department of biological chemical and pharmaceutical sciences and technologies, University of Palermo, Palermo, Italy
| | - Giovanni Zummo
- Department of Experimental Biomedicine and Clinical Neurosciences, University of Palermo, Palermo, Italy
| | - Donatella Bulone
- Institute of Biophysics, National Research Council, Palermo, Italy
| | - Everly Conway de Macario
- Department of Microbiology and Immunology, School of Medicine, University of Maryland at Baltimore, and Institute of Marine and Environmental Technology, Columbus Center, Baltimore, Maryland, United States of America
| | - Alberto J. L. Macario
- Euro-Mediterranean Institute of Science and Technology, Palermo, Italy
- Department of Microbiology and Immunology, School of Medicine, University of Maryland at Baltimore, and Institute of Marine and Environmental Technology, Columbus Center, Baltimore, Maryland, United States of America
| | | | - Francesco Cappello
- Institute of Biophysics, National Research Council, Palermo, Italy
- Department of Experimental Biomedicine and Clinical Neurosciences, University of Palermo, Palermo, Italy
- Euro-Mediterranean Institute of Science and Technology, Palermo, Italy
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18
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Class A β-lactamases as versatile scaffolds to create hybrid enzymes: applications from basic research to medicine. BIOMED RESEARCH INTERNATIONAL 2013; 2013:827621. [PMID: 24066299 PMCID: PMC3771265 DOI: 10.1155/2013/827621] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 07/04/2013] [Indexed: 01/13/2023]
Abstract
Designing hybrid proteins is a major aspect of protein engineering and covers a very wide range of applications from basic research to medical applications. This review focuses on the use of class A β-lactamases as versatile scaffolds to design hybrid enzymes (referred to as β-lactamase hybrid proteins, BHPs) in which an exogenous peptide, protein or fragment thereof is inserted at various permissive positions. We discuss how BHPs can be specifically designed to create bifunctional proteins, to produce and to characterize proteins that are otherwise difficult to express, to determine the epitope of specific antibodies, to generate antibodies against nonimmunogenic epitopes, and to better understand the structure/function relationship of proteins.
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19
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Michalek M, Salnikov E, Bechinger B. Structure and topology of the huntingtin 1-17 membrane anchor by a combined solution and solid-state NMR approach. Biophys J 2013; 105:699-710. [PMID: 23931318 PMCID: PMC3736738 DOI: 10.1016/j.bpj.2013.06.030] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Revised: 06/07/2013] [Accepted: 06/17/2013] [Indexed: 10/26/2022] Open
Abstract
The very amino-terminal domain of the huntingtin protein is directly located upstream of the protein's polyglutamine tract, plays a decisive role in several important properties of this large protein and in the development of Huntington's disease. This huntingtin 1-17 domain is on the one hand known to markedly increase polyglutamine aggregation rates and on the other hand has been shown to be involved in cellular membrane interactions. Here, we determined the high-resolution structure of huntingtin 1-17 in dodecyl phosphocholine micelles and the topology of its helical domain in oriented phosphatidylcholine bilayers. Using two-dimensional solution NMR spectroscopy the low-energy conformations of the polypeptide were identified in the presence of dodecyl phosphocholine detergent micelles. In a next step a set of four solid-state NMR angular restraints was obtained from huntingtin 1-17 labeled with (15)N and (2)H at selected sites. Of the micellar ensemble of helical conformations only a limited set agrees in quantitative detail with the solid-state angular restraints of huntingtin 1-17 obtained in supported planar lipid bilayers. Thereby, the solid-state NMR data were used to further refine the domain structure in phospholipid bilayers. At the same time its membrane topology was determined and different motional regimes of this membrane-associated domain were explored. The pronounced structural transitions of huntingtin 1-17 upon membrane-association result in a α-helical conformation from K6 to F17, i.e., up to the very start of the polyglutamine tract. This amphipathic helix is aligned nearly parallel to the membrane surface (tilt angle ∼77°) and is characterized by a hydrophobic ridge on one side and an alternation of cationic and anionic residues that run along the hydrophilic face of the helix. This arrangement facilitates electrostatic interactions between huntingtin 1-17 domains and possibly with the proximal polyglutamine tract.
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Affiliation(s)
| | | | - Burkhard Bechinger
- Université de Strasbourg/CNRS, UMR7177, Institut de Chimie, Strasbourg, France
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20
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Menon RP, Nethisinghe S, Faggiano S, Vannocci T, Rezaei H, Pemble S, Sweeney MG, Wood NW, Davis MB, Pastore A, Giunti P. The role of interruptions in polyQ in the pathology of SCA1. PLoS Genet 2013; 9:e1003648. [PMID: 23935513 PMCID: PMC3723530 DOI: 10.1371/journal.pgen.1003648] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Accepted: 06/04/2013] [Indexed: 11/18/2022] Open
Abstract
At least nine dominant neurodegenerative diseases are caused by expansion of CAG repeats in coding regions of specific genes that result in abnormal elongation of polyglutamine (polyQ) tracts in the corresponding gene products. When above a threshold that is specific for each disease the expanded polyQ repeats promote protein aggregation, misfolding and neuronal cell death. The length of the polyQ tract inversely correlates with the age at disease onset. It has been observed that interruption of the CAG tract by silent (CAA) or missense (CAT) mutations may strongly modulate the effect of the expansion and delay the onset age. We have carried out an extensive study in which we have complemented DNA sequence determination with cellular and biophysical models. By sequencing cloned normal and expanded SCA1 alleles taken from our cohort of ataxia patients we have determined sequence variations not detected by allele sizing and observed for the first time that repeat instability can occur even in the presence of CAG interruptions. We show that histidine interrupted pathogenic alleles occur with relatively high frequency (11%) and that the age at onset inversely correlates linearly with the longer uninterrupted CAG stretch. This could be reproduced in a cellular model to support the hypothesis of a linear behaviour of polyQ. We clarified by in vitro studies the mechanism by which polyQ interruption slows down aggregation. Our study contributes to the understanding of the role of polyQ interruption in the SCA1 phenotype with regards to age at disease onset, prognosis and transmission. Spinocerebellar ataxia type 1 (SCA1) is a progressive neurodegenerative disorder resulting in loss of coordination and balance. It is caused by an expanded repeated DNA sequence (CAG) in the gene ATXN1. The CAG repeat region is normally interrupted by the DNA sequence CAT. Loss of this interruption is believed to cause instability whereby the CAG repeat expands beyond a key threshold resulting, ultimately, in polyglutamine protein aggregation and cell death. Here we examine how interruptions influence pathology in patients and establish a cellular model to support our findings. We distinguish our patients into two sub-groups based on whether or not their expanded CAG repeat stretches contained an interruption. This is not possible with conventional diagnostic techniques. Differentiating the sub-group with no interruptions led to improved accuracy in predicting their age at onset. The other sub-group, with interruptions, reveals a delay in age at onset that shows greater alignment with the longest stretch of CAG repeats. These findings are significant for genetic counselling and prognosis. Our cellular model and in vitro studies confirmed the relationship between disease severity and uninterrupted repeat length and showed that interruptions do not significantly affect the polyglutamine protein aggregation, but do slow down the aggregation rate.
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Affiliation(s)
| | - Suran Nethisinghe
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, United Kingdom
| | | | | | - Human Rezaei
- Department of Protein Macroassemblies and Prion Pathology, INRA, Domain de Vilvert, Jouy en Josas, France
| | - Sally Pemble
- Neurogenetics Unit, National Hospital for Neurology and Neurosurgery, London, United Kingdom
| | - Mary G. Sweeney
- Neurogenetics Unit, National Hospital for Neurology and Neurosurgery, London, United Kingdom
| | - Nicholas W. Wood
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, United Kingdom
| | - Mary B. Davis
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, United Kingdom
| | | | - Paola Giunti
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, United Kingdom
- * E-mail: (AP); (PG)
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21
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Almeida B, Fernandes S, Abreu IA, Macedo-Ribeiro S. Trinucleotide repeats: a structural perspective. Front Neurol 2013; 4:76. [PMID: 23801983 PMCID: PMC3687200 DOI: 10.3389/fneur.2013.00076] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Accepted: 06/04/2013] [Indexed: 11/29/2022] Open
Abstract
Trinucleotide repeat (TNR) expansions are present in a wide range of genes involved in several neurological disorders, being directly involved in the molecular mechanisms underlying pathogenesis through modulation of gene expression and/or the function of the RNA or protein it encodes. Structural and functional information on the role of TNR sequences in RNA and protein is crucial to understand the effect of TNR expansions in neurodegeneration. Therefore, this review intends to provide to the reader a structural and functional view of TNR and encoded homopeptide expansions, with a particular emphasis on polyQ expansions and its role at inducing the self-assembly, aggregation and functional alterations of the carrier protein, which culminates in neuronal toxicity and cell death. Detail will be given to the Machado-Joseph Disease-causative and polyQ-containing protein, ataxin-3, providing clues for the impact of polyQ expansion and its flanking regions in the modulation of ataxin-3 molecular interactions, function, and aggregation.
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Affiliation(s)
- Bruno Almeida
- Instituto de Biologia Molecular e Celular, Universidade do Porto , Porto , Portugal
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Burke KA, Kauffman KJ, Umbaugh CS, Frey SL, Legleiter J. The interaction of polyglutamine peptides with lipid membranes is regulated by flanking sequences associated with huntingtin. J Biol Chem 2013; 288:14993-5005. [PMID: 23572526 DOI: 10.1074/jbc.m112.446237] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Huntington disease (HD) is caused by an expanded polyglutamine (poly(Q)) repeat near the N terminus of the huntingtin (htt) protein. Expanded poly(Q) facilitates formation of htt aggregates, eventually leading to deposition of cytoplasmic and intranuclear inclusion bodies containing htt. Flanking sequences directly adjacent to the poly(Q) domain, such as the first 17 amino acids on the N terminus (Nt17) and the polyproline (poly(P)) domain on the C-terminal side of the poly(Q) domain, heavily influence aggregation. Additionally, htt interacts with a variety of membraneous structures within the cell, and Nt17 is implicated in lipid binding. To investigate the interaction between htt exon1 and lipid membranes, a combination of in situ atomic force microscopy, Langmuir trough techniques, and vesicle permeability assays were used to directly monitor the interaction of a variety of synthetic poly(Q) peptides with different combinations of flanking sequences (KK-Q35-KK, KK-Q35-P10-KK, Nt17-Q35-KK, and Nt17-Q35-P10-KK) on model membranes and surfaces. Each peptide aggregated on mica, predominately forming extended, fibrillar aggregates. In contrast, poly(Q) peptides that lacked the Nt17 domain did not appreciably aggregate on or insert into lipid membranes. Nt17 facilitated the interaction of peptides with lipid surfaces, whereas the poly(P) region enhanced this interaction. The aggregation of Nt17-Q35-P10-KK on the lipid bilayer closely resembled that of a htt exon1 construct containing 35 repeat glutamines. Collectively, this data suggests that the Nt17 domain plays a critical role in htt binding and aggregation on lipid membranes, and this lipid/htt interaction can be further modulated by the presence of the poly(P) domain.
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Affiliation(s)
- Kathleen A Burke
- C Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26505, USA
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Michalek M, Salnikov ES, Werten S, Bechinger B. Membrane interactions of the amphipathic amino terminus of huntingtin. Biochemistry 2013; 52:847-58. [PMID: 23305455 DOI: 10.1021/bi301325q] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The amino-terminal domain of huntingtin (Htt17), located immediately upstream of the decisive polyglutamine tract, strongly influences important properties of this large protein and thereby the development of Huntington's disease. Htt17 markedly increases polyglutamine aggregation rates and the level of huntingtin's interactions with biological membranes. Htt17 adopts a largely helical conformation in the presence of membranes, and this structural transition was used to quantitatively analyze membrane association as a function of lipid composition. The apparent membrane partitioning constants increased in the presence of anionic lipids but decreased with increasing amounts of cholesterol. When membrane permeabilization was tested, a pronounced dye release was observed from 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) vesicles and 75:25 (molar ratio) POPC/1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-l-serine vesicles but not across bilayers that better mimic cellular membranes. Solid-state nuclear magnetic resonance structural investigations indicated that the Htt17 α-helix adopts an alignment parallel to the membrane surface, and that the tilt angle (∼75°) was nearly constant in all of the membranes that were investigated. Furthermore, the addition of Htt17 resulted in a decrease in the lipid order parameter in all of the membranes that were investigated. The lipid interactions of Htt17 have pivotal implications for membrane anchoring and functional properties of huntingtin and concomitantly the development of the disease.
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Affiliation(s)
- Matthias Michalek
- Membrane Biophysics and NMR Chemistry Institute UMR7177, University of Strasbourg/CNRS International Center for Frontier Research in Chemistry, 1 rue Blaise Pascal, Strasbourg, France
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Espargaró A, Villar-Piqué A, Sabaté R, Ventura S. Yeast prions form infectious amyloid inclusion bodies in bacteria. Microb Cell Fact 2012; 11:89. [PMID: 22731490 PMCID: PMC3520751 DOI: 10.1186/1475-2859-11-89] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2012] [Accepted: 05/27/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Prions were first identified as infectious proteins associated with fatal brain diseases in mammals. However, fungal prions behave as epigenetic regulators that can alter a range of cellular processes. These proteins propagate as self-perpetuating amyloid aggregates being an example of structural inheritance. The best-characterized examples are the Sup35 and Ure2 yeast proteins, corresponding to [PSI+] and [URE3] phenotypes, respectively. RESULTS Here we show that both the prion domain of Sup35 (Sup35-NM) and the Ure2 protein (Ure2p) form inclusion bodies (IBs) displaying amyloid-like properties when expressed in bacteria. These intracellular aggregates template the conformational change and promote the aggregation of homologous, but not heterologous, soluble prionogenic molecules. Moreover, in the case of Sup35-NM, purified IBs are able to induce different [PSI+] phenotypes in yeast, indicating that at least a fraction of the protein embedded in these deposits adopts an infectious prion fold. CONCLUSIONS An important feature of prion inheritance is the existence of strains, which are phenotypic variants encoded by different conformations of the same polypeptide. We show here that the proportion of infected yeast cells displaying strong and weak [PSI+] phenotypes depends on the conditions under which the prionogenic aggregates are formed in E. coli, suggesting that bacterial systems might become useful tools to generate prion strain diversity.
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Affiliation(s)
- Alba Espargaró
- Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona, Bellaterra, Spain
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25
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De Los Rios P, Hafner M, Pastore A. Explaining the length threshold of polyglutamine aggregation. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:244105. [PMID: 22595533 DOI: 10.1088/0953-8984/24/24/244105] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The existence of a length threshold, of about 35 residues, above which polyglutamine repeats can give rise to aggregation and to pathologies, is one of the hallmarks of polyglutamine neurodegenerative diseases such as Huntington's disease. The reason why such a minimal length exists at all has remained one of the main open issues in research on the molecular origins of such classes of diseases. Following the seminal proposals of Perutz, most research has focused on the hunt for a special structure, attainable only above the minimal length, able to trigger aggregation. Such a structure has remained elusive and there is growing evidence that it might not exist at all. Here we review some basic polymer and statistical physics facts and show that the existence of a threshold is compatible with the modulation that the repeat length imposes on the association and dissociation rates of polyglutamine polypeptides to and from oligomers. In particular, their dramatically different functional dependence on the length rationalizes the very presence of a threshold and hints at the cellular processes that might be at play, in vivo, to prevent aggregation and the consequent onset of the disease.
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Affiliation(s)
- Paolo De Los Rios
- Laboratory of Statistical Biophysics, ITP SB EPFL, Lausanne, Switzerland.
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26
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Temperature profoundly affects ataxin-3 fibrillogenesis. Biochimie 2012; 94:1026-31. [DOI: 10.1016/j.biochi.2012.01.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Accepted: 01/03/2012] [Indexed: 12/16/2022]
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Scarafone N, Pain C, Fratamico A, Gaspard G, Yilmaz N, Filée P, Galleni M, Matagne A, Dumoulin M. Amyloid-like fibril formation by polyQ proteins: a critical balance between the polyQ length and the constraints imposed by the host protein. PLoS One 2012; 7:e31253. [PMID: 22438863 PMCID: PMC3305072 DOI: 10.1371/journal.pone.0031253] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Accepted: 01/05/2012] [Indexed: 11/18/2022] Open
Abstract
Nine neurodegenerative disorders, called polyglutamine (polyQ) diseases, are characterized by the formation of intranuclear amyloid-like aggregates by nine proteins containing a polyQ tract above a threshold length. These insoluble aggregates and/or some of their soluble precursors are thought to play a role in the pathogenesis. The mechanism by which polyQ expansions trigger the aggregation of the relevant proteins remains, however, unclear. In this work, polyQ tracts of different lengths were inserted into a solvent-exposed loop of the β-lactamase BlaP and the effects of these insertions on the properties of BlaP were investigated by a range of biophysical techniques. The insertion of up to 79 glutamines does not modify the structure of BlaP; it does, however, significantly destabilize the enzyme. The extent of destabilization is largely independent of the polyQ length, allowing us to study independently the effects intrinsic to the polyQ length and those related to the structural integrity of BlaP on the aggregating properties of the chimeras. Only chimeras with 55Q and 79Q readily form amyloid-like fibrils; therefore, similarly to the proteins associated with diseases, there is a threshold number of glutamines above which the chimeras aggregate into amyloid-like fibrils. Most importantly, the chimera containing 79Q forms amyloid-like fibrils at the same rate whether BlaP is folded or not, whereas the 55Q chimera aggregates into amyloid-like fibrils only if BlaP is unfolded. The threshold value for amyloid-like fibril formation depends, therefore, on the structural integrity of the β-lactamase moiety and thus on the steric and/or conformational constraints applied to the polyQ tract. These constraints have, however, no significant effect on the propensity of the 79Q tract to trigger fibril formation. These results suggest that the influence of the protein context on the aggregating properties of polyQ disease-associated proteins could be negligible when the latter contain particularly long polyQ tracts.
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Affiliation(s)
- Natacha Scarafone
- Laboratory of Enzymology and Protein Folding, Centre for Protein Engineering, Institute of Chemistry, University of Liège, Liège, Belgium
| | - Coralie Pain
- Laboratory of Enzymology and Protein Folding, Centre for Protein Engineering, Institute of Chemistry, University of Liège, Liège, Belgium
| | - Anthony Fratamico
- Laboratory of Enzymology and Protein Folding, Centre for Protein Engineering, Institute of Chemistry, University of Liège, Liège, Belgium
| | - Gilles Gaspard
- Biological Macromolecules, Centre for Protein Engineering, Institute of Chemistry, University of Liège, Liège, Belgium
| | - Nursel Yilmaz
- Biological Macromolecules, Centre for Protein Engineering, Institute of Chemistry, University of Liège, Liège, Belgium
| | - Patrice Filée
- Biological Macromolecules, Centre for Protein Engineering, Institute of Chemistry, University of Liège, Liège, Belgium
| | - Moreno Galleni
- Biological Macromolecules, Centre for Protein Engineering, Institute of Chemistry, University of Liège, Liège, Belgium
| | - André Matagne
- Laboratory of Enzymology and Protein Folding, Centre for Protein Engineering, Institute of Chemistry, University of Liège, Liège, Belgium
| | - Mireille Dumoulin
- Laboratory of Enzymology and Protein Folding, Centre for Protein Engineering, Institute of Chemistry, University of Liège, Liège, Belgium
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28
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Wetzel R. Physical chemistry of polyglutamine: intriguing tales of a monotonous sequence. J Mol Biol 2012; 421:466-90. [PMID: 22306404 DOI: 10.1016/j.jmb.2012.01.030] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Accepted: 01/18/2012] [Indexed: 01/08/2023]
Abstract
Polyglutamine (polyQ) sequences of unknown normal function are present in a significant number of proteins, and their repeat expansion is associated with a number of genetic neurodegenerative diseases. PolyQ solution structure and properties are important not only because of the normal and abnormal biology associated with these sequences but also because they represent an interesting case of a biologically relevant homopolymer. As the common thread in expanded polyQ repeat diseases, it is important to understand the structure and properties of simple polyQ sequences. At the same time, experience has shown that sequences attached to polyQ, whether in artificial constructs or in disease proteins, can influence structure and properties. The two major contenders for the molecular source of the neurotoxicity implicit in polyQ expansion within disease proteins are a populated toxic conformation in the monomer ensemble and a toxic aggregated species. This review summarizes experimental and computational studies on the solution structure and aggregation properties of both simple and complex polyQ sequences, and their repeat-length dependence. As a representative of complex polyQ proteins, the behavior of huntingtin N-terminal fragments, such as exon-1, receives special attention.
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Affiliation(s)
- Ronald Wetzel
- Department of Structural Biology and Pittsburgh Institute for Neurodegenerative Disease, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA.
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29
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Affiliation(s)
- S H Subramony
- McKnight Brain Institute at UF, Gainesville, FL 32610, USA.
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30
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Kumar P, Pradhan K, Karunya R, Ambasta RK, Querfurth HW. Cross-functional E3 ligases Parkin and C-terminus Hsp70-interacting protein in neurodegenerative disorders. J Neurochem 2011; 120:350-70. [DOI: 10.1111/j.1471-4159.2011.07588.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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31
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Hinz J, Lehnhardt L, Zakrzewski S, Zhang G, Ignatova Z. Polyglutamine expansion alters the dynamics and molecular architecture of aggregates in dentatorubropallidoluysian atrophy. J Biol Chem 2011; 287:2068-78. [PMID: 22134925 DOI: 10.1074/jbc.m111.318915] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Preferential accumulation of mutant proteins in the nucleus has been suggested to be the molecular culprit that confers cellular toxicity in the neurodegenerative disorders caused by polyglutamine (polyQ) expansion. Here, we use dynamic imaging approaches, orthogonal cross-seeding, and composition analysis to examine the dynamics and structure of nuclear and cytoplasmic inclusions of atrophin-1, implicated in dentatorubropallidoluysian atrophy, a polyQ-based disease with complex clinical features. Our results reveal a large heterogeneity in the dynamics of the nuclear inclusions compared with the compact and immobile cytoplasmic aggregates. At least two types of inclusions of expanded atrophin-1 with different mobility of the molecular species and ability to exchange with the surrounding monomer pool coexist in the nucleus. Intriguingly, the enrichment of nuclear inclusions with slow dynamics parallels changes in the aggregate core architecture that are dominated by the polyQ stretch. We propose that the observed complexity in the dynamics of the nuclear inclusions provides a molecular explanation for the enhanced cellular toxicity of the nuclear aggregates in polyQ-based neurodegeneration.
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Affiliation(s)
- Justyna Hinz
- Institute of Biochemistry and Biology, University of Potsdam, 14467 Potsdam, Germany
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32
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Location trumps length: polyglutamine-mediated changes in folding and aggregation of a host protein. Biophys J 2011; 100:2773-82. [PMID: 21641323 DOI: 10.1016/j.bpj.2011.04.028] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2011] [Revised: 04/05/2011] [Accepted: 04/08/2011] [Indexed: 11/21/2022] Open
Abstract
Expanded CAG diseases are progressive neurodegenerative disorders in which specific proteins have an unusually long polyglutamine stretch. Although these proteins share no other sequence or structural homologies, they all aggregate into intracellular inclusions that are believed to be pathological. We sought to determine what impact the position and number of glutamines have on the structure and aggregation of the host protein, apomyoglobin. Variable-length polyQ tracts were inserted either into the loop between the C- and D-helices (Q(n)CD) or at the N-terminus (Q(n)NT). The Q(n)CD mutants lost some α-helix and gained unordered and/or β-sheet in a length-dependent manner. These mutants were partially unfolded and rapidly assembled into soluble chain-like oligomers. In sharp contrast, the Q(n)NT mutants largely retained wild-type tertiary structure but associated into long, fibrillar aggregates. Control proteins with glycine-serine repeats (GS(8)CD and GS(8)NT) were produced. GS(8)CD exhibited similar structural perturbations and aggregation characteristics to an analogously sized Q(16)CD, indicating that the observed effects are independent of amino acid composition. In contrast to Q(16)NT, GS(8)NT did not form fibrillar aggregates. Thus, soluble oligomers are produced through structural perturbation and do not require polyQ, whereas classic fibrils arise from specific polyQ intermolecular interactions in the absence of misfolding.
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33
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Długosz M, Trylska J. Secondary structures of native and pathogenic huntingtin N-terminal fragments. J Phys Chem B 2011; 115:11597-608. [PMID: 21910495 DOI: 10.1021/jp206373g] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Huntington's disease is a neurodegenerative disorder caused by a polyglutamine (polyQ) expansion in the N-terminal fragment of the Huntingtin (Htt) protein. Structural properties of Htt N-terminal regions and the molecular mechanism leading to protein aggregation have not been fully explained yet. We performed all-atom replica exchange molecular dynamics to investigate the structures of Htt N-terminal parts with polyQ tracts of nonpathogenic and pathogenic lengths. The monomers were composed of the headpiece (17 N-terminal residues), a polyQ tract (polyQ(17) for native and polyQ(55) for pathogenic sequence), and a polyP(11) region, followed by 17 amino acids of mixed sequence. We found that corresponding regions in both fragments fold to similar secondary structures; the headpiece and polyQ stretch adopt mainly α-helical conformations, and polyP(11) forms the PP II-type helix. The native N-terminal fragment is more compact and stabilized by hydrophobic interactions between the surface of polyP(11) and the amphipathic helix of the headpiece. In the pathogenic fragment the headpiece is solvent exposed and does not interact with polyP(11). The predicted structure of the native N-terminal fragment agrees with the X-ray structure of the Htt first exon containing polyQ(17). The structure of the pathogenic fragment adheres to an aggregation model that is mediated by the Htt headpiece.
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Affiliation(s)
- Maciej Długosz
- Interdisciplinary Centre for Mathematical and Computational Modelling, University of Warsaw, Żwirki i Wigury 93, Warsaw 02-089, Poland.
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Masino L, Nicastro G, De Simone A, Calder L, Molloy J, Pastore A. The Josephin domain determines the morphological and mechanical properties of ataxin-3 fibrils. Biophys J 2011; 100:2033-42. [PMID: 21504740 PMCID: PMC3077691 DOI: 10.1016/j.bpj.2011.02.056] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2010] [Revised: 02/15/2011] [Accepted: 02/25/2011] [Indexed: 12/15/2022] Open
Abstract
Fibrillar aggregation of the protein ataxin-3 is linked to the inherited neurodegenerative disorder Spinocerebellar ataxia type 3, a member of the polyQ expansion disease family. We previously reported that aggregation and stability of the nonpathological form of ataxin-3, carrying an unexpanded polyQ tract, are modulated by its N-terminal Josephin domain. It was also shown that expanded ataxin-3 aggregates via a two-stage mechanism initially involving Josephin self-association, followed by a polyQ-dependent step. Despite this recent progress, however, the exact mechanism of ataxin-3 fibrilization remains elusive. Here, we have used electron microscopy, atomic force microscopy, and other biophysical techniques to characterize the morphological and mechanical properties of nonexpanded ataxin-3 fibrils. By comparing aggregates of ataxin-3 and of the isolated Josephin domain, we show that the two proteins self-assemble into fibrils with markedly similar features over the temperature range 37-50°C. Estimates of persistence length and Young's modulus of the fibrils reveal a great flexibility. Our data indicate that, under physiological conditions, during early aggregation Josephin retains a nativelike secondary structure but loses its enzymatic activity. The results suggest a key role of Josephin in ataxin-3 fibrillar aggregation.
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Affiliation(s)
- Laura Masino
- Division of Molecular Structure, Medical Research Council, National Institute for Medical Research, London, United Kingdom
| | - Giuseppe Nicastro
- Division of Molecular Structure, Medical Research Council, National Institute for Medical Research, London, United Kingdom
| | - Alfonso De Simone
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Lesley Calder
- Division of Molecular Structure, Medical Research Council, National Institute for Medical Research, London, United Kingdom
| | - Justin Molloy
- Division of Molecular Structure, Medical Research Council, National Institute for Medical Research, London, United Kingdom
| | - Annalisa Pastore
- Division of Molecular Structure, Medical Research Council, National Institute for Medical Research, London, United Kingdom
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35
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Kar K, Jayaraman M, Sahoo B, Kodali R, Wetzel R. Critical nucleus size for disease-related polyglutamine aggregation is repeat-length dependent. Nat Struct Mol Biol 2011; 18:328-36. [PMID: 21317897 PMCID: PMC3075957 DOI: 10.1038/nsmb.1992] [Citation(s) in RCA: 175] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2010] [Accepted: 11/24/2010] [Indexed: 01/29/2023]
Abstract
Because polyglutamine (polyQ) aggregate formation has been implicated as playing an important role in expanded CAG repeat diseases, it is important to understand the biophysics underlying the initiation of aggregation. Previously, we showed that relatively long polyQ peptides aggregate by nucleated growth polymerization and a monomeric critical nucleus. We show here that over a short range of repeat lengths, from Q(23) to Q(26), the size of the critical nucleus for aggregation increases from monomeric to dimeric to tetrameric. This variation in nucleus size suggests a common duplex antiparallel β-sheet framework for the nucleus, and it further supports the feasibility of an organized monomeric aggregation nucleus for longer polyQ repeat peptides. The data also suggest that a change in the size of aggregation nuclei may have a role in the pathogenicity of polyQ expansion in this series of familial neurodegenerative diseases.
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Affiliation(s)
- Karunakar Kar
- Structural Biology Department, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
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36
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Assessing mutant huntingtin fragment and polyglutamine aggregation by atomic force microscopy. Methods 2010; 53:275-84. [PMID: 21187152 DOI: 10.1016/j.ymeth.2010.12.028] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2010] [Revised: 12/18/2010] [Accepted: 12/18/2010] [Indexed: 01/01/2023] Open
Abstract
Huntington disease (HD), a neurodegenerative disorder, is caused by an expansion of more than 35-40 polyglutamine (polyQ) repeats located near the N-terminus of the huntingtin (htt) protein. The expansion of the polyQ domain results in the ordered assembly of htt fragments into fibrillar aggregates that are the main constituents of inclusion bodies, which are a hallmark of the disease. This paper describes protocols for studying the aggregation of mutant htt fragments and synthetic polyQ peptides with atomic force microscopy (AFM). Ex situ AFM is used to characterize aggregate formation in protein incubation as a function of time. Methods to quickly and unambiguously distinguish specific aggregate species from complex, heterogeneous aggregation reactions based on simple morphological features are presented. Finally, the application of time lapse atomic force microscopy in solution is presented for studying synthetic model polyQ peptides, which allows for tracking the formation and fate of individual aggregates on surfaces over time. This ability allows for dynamic studies of the aggregation process and direct observation of the interplay between different types of aggregates.
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37
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The composition of the polyglutamine-containing proteins influences their co-aggregation properties. Cell Biol Int 2010; 34:933-42. [PMID: 20515443 DOI: 10.1042/cbi20090474] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The sequestration of crucial cellular proteins into insoluble aggregates formed by the polypeptides containing expanded polyglutamine tracts has been proposed to be the key mechanism responsible for the abnormal cell functioning in the so-called polyglutamine diseases. To evaluate to what extent the ability of polyglutamine sequences to recruit other proteins into the intracellular aggregates depends on the composition of the aggregating peptide, we analysed the co-aggregation properties of the N-terminal fragment of huntingtin fused with unrelated non-aggregating and/or self-aggregating peptides. We show that the ability of the mutated N-terminal huntingtin fragment to sequester non-related proteins can be significantly increased by fusion with the non-aggregating reporter protein [GFP (green fluorescence protein)]. By contrast, fusion with the self-aggregating C-terminal fragment of the CFTR (cystic fibrosis transmembrane conductance regulator) dramatically reduces the sequestration of related non-fused huntingtin fragments. We also demonstrate that the co-aggregation of different non-fused N-terminal huntingtin fragments depends on their length, with long fragments of the wild-type huntingtin not only excluded from the nuclear inclusions, but also very inefficiently sequestered into the cytoplasmic aggregates formed by the short fragments of mutant protein. Additionally, our results suggest that atypical intracellular aggregation patterns, which include unusual distribution and/or morphology of protein aggregates, are associated with altered ability of accumulating proteins to co-aggregate with other peptides.
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38
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Robertson AL, Headey SJ, Saunders HM, Ecroyd H, Scanlon MJ, Carver JA, Bottomley SP. Small heat-shock proteins interact with a flanking domain to suppress polyglutamine aggregation. Proc Natl Acad Sci U S A 2010; 107:10424-9. [PMID: 20484674 PMCID: PMC2890844 DOI: 10.1073/pnas.0914773107] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Small heat-shock proteins (sHsps) are molecular chaperones that play an important protective role against cellular protein misfolding by interacting with partially unfolded proteins on their off-folding pathway, preventing their aggregation. Polyglutamine (polyQ) repeat expansion leads to the formation of fibrillar protein aggregates and neuronal cell death in nine diseases, including Huntington disease and the spinocerebellar ataxias (SCAs). There is evidence that sHsps have a role in suppression of polyQ-induced neurodegeneration; for example, the sHsp alphaB-crystallin (alphaB-c) has been identified as a suppressor of SCA3 toxicity in a Drosophila model. However, the molecular mechanism for this suppression is unknown. In this study we tested the ability of alphaB-c to suppress the aggregation of a polyQ protein. We found that alphaB-c does not inhibit the formation of SDS-insoluble polyQ fibrils. We further tested the effect of alphaB-c on the aggregation of ataxin-3, a polyQ protein that aggregates via a two-stage aggregation mechanism. The first stage involves association of the N-terminal Josephin domain followed by polyQ-mediated interactions and the formation of SDS-resistant mature fibrils. Our data show that alphaB-c potently inhibits the first stage of ataxin-3 aggregation; however, the second polyQ-dependent stage can still proceed. By using NMR spectroscopy, we have determined that alphaB-c interacts with an extensive region on the surface of the Josephin domain. These data provide an example of a domain/region flanking an amyloidogenic sequence that has a critical role in modulating aggregation of a polypeptide and plays a role in the interaction with molecular chaperones to prevent this aggregation.
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Affiliation(s)
- Amy L. Robertson
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, 3800, Australia
| | - Stephen J. Headey
- Medicinal Chemistry and Drug Action, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, 3052, Australia
| | - Helen M. Saunders
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, 3800, Australia
| | - Heath Ecroyd
- School of Biological Sciences, University of Wollongong, Wollongong, New South Wales, 2522, Australia; and
| | - Martin J. Scanlon
- Medicinal Chemistry and Drug Action, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, 3052, Australia
| | - John A. Carver
- School of Chemistry and Physics, The University of Adelaide, Adelaide, South Australia, 5005, Australia
| | - Stephen P. Bottomley
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, 3800, Australia
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Legleiter J, Mitchell E, Lotz GP, Sapp E, Ng C, DiFiglia M, Thompson LM, Muchowski PJ. Mutant huntingtin fragments form oligomers in a polyglutamine length-dependent manner in vitro and in vivo. J Biol Chem 2010; 285:14777-90. [PMID: 20220138 PMCID: PMC2863238 DOI: 10.1074/jbc.m109.093708] [Citation(s) in RCA: 163] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2009] [Revised: 03/03/2010] [Indexed: 11/06/2022] Open
Abstract
Huntington disease (HD) is caused by an expansion of more than 35-40 polyglutamine (polyQ) repeats in the huntingtin (htt) protein, resulting in accumulation of inclusion bodies containing fibrillar deposits of mutant htt fragments. Intriguingly, polyQ length is directly proportional to the propensity for htt to form fibrils and the severity of HD and is inversely correlated with age of onset. Although the structural basis for htt toxicity is unclear, the formation, abundance, and/or persistence of toxic conformers mediating neuronal dysfunction and degeneration in HD must also depend on polyQ length. Here we used atomic force microscopy to demonstrate mutant htt fragments and synthetic polyQ peptides form oligomers in a polyQ length-dependent manner. By time-lapse atomic force microscopy, oligomers form before fibrils, are transient in nature, and are occasionally direct precursors to fibrils. However, the vast majority of fibrils appear to form by monomer addition coinciding with the disappearance of oligomers. Thus, oligomers must undergo a major structural transition preceding fibril formation. In an immortalized striatal cell line and in brain homogenates from a mouse model of HD, a mutant htt fragment formed oligomers in a polyQ length-dependent manner that were similar in size to those formed in vitro, although these structures accumulated over time in vivo. Finally, using immunoelectron microscopy, we detected oligomeric-like structures in human HD brains. These results demonstrate that oligomer formation by a mutant htt fragment is strongly polyQ length-dependent in vitro and in vivo, consistent with a causative role for these structures, or subsets of these structures, in HD pathogenesis.
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Affiliation(s)
- Justin Legleiter
- From the Gladstone Institute of Neurological Disease and
- Departments of Neurology and
| | - Emily Mitchell
- Departments of Psychiatry and Human Behavior
- Neurobiology and Behavior, and
- Biological Chemistry, University of California, Irvine, California 92697, and
| | - Gregor P. Lotz
- From the Gladstone Institute of Neurological Disease and
- Departments of Neurology and
| | - Ellen Sapp
- the Laboratory of Cellular Neurobiology, Department of Neurology, Massachusetts General Hospital, Charlestown, Massachusetts 02114
| | - Cheping Ng
- From the Gladstone Institute of Neurological Disease and
| | - Marian DiFiglia
- the Laboratory of Cellular Neurobiology, Department of Neurology, Massachusetts General Hospital, Charlestown, Massachusetts 02114
| | - Leslie M. Thompson
- Departments of Psychiatry and Human Behavior
- Neurobiology and Behavior, and
- Biological Chemistry, University of California, Irvine, California 92697, and
| | - Paul J. Muchowski
- From the Gladstone Institute of Neurological Disease and
- Departments of Neurology and
- Biochemistry and Biophysics, University of California, San Francisco, California 94158
- the Taube-Koret Center for Huntington's Disease Research and
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Williamson TE, Vitalis A, Crick SL, Pappu RV. Modulation of polyglutamine conformations and dimer formation by the N-terminus of huntingtin. J Mol Biol 2010; 396:1295-309. [PMID: 20026071 PMCID: PMC2832287 DOI: 10.1016/j.jmb.2009.12.017] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2009] [Revised: 11/20/2009] [Accepted: 12/10/2009] [Indexed: 11/28/2022]
Abstract
Polyglutamine expansions within different proteins are associated with nine different neurodegenerative diseases. There is growing interest in understanding the roles of flanking sequences from disease-relevant proteins in the intrinsic conformational and aggregation properties of polyglutamine. We report results from atomistic simulations and circular dichroism experiments that quantify the effect of the N-terminal 17-residue (Nt17) segment of the huntingtin protein on polyglutamine conformations and intermolecular interactions. We show that the Nt17 segment and polyglutamine domains become increasingly disordered as polyglutamine length (N) increases in Nt17-Q(N) constructs. Hydrophobic groups within Nt17 become sequestered in intramolecular interdomain interfaces. We also show that the Nt17 segment suppresses the intrinsic propensity of polyglutamine aggregation. This inhibition arises from the incipient micellar structures adopted by monomeric forms of the peptides with Nt17 segments. The degree of intermolecular association increases with increasing polyglutamine length and is governed mainly by associations between polyglutamine domains. Comparative analysis of intermolecular associations for different polyglutamine-containing constructs leads to clearer interpretations of recently published experimental data. Our results suggest a framework for fibril formation and identify roles for flanking sequences in the modulation of polyglutamine aggregation.
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Affiliation(s)
- Tim E. Williamson
- Department of Biomedical Engineering, Washington University in St. Louis, One Brookings Drive, Campus Box 1097, St. Louis, MO 63130
- Center for Computational Biology, Washington University in St. Louis, One Brookings Drive, Campus Box 1097, St. Louis, MO 63130
| | - Andreas Vitalis
- Center for Computational Biology, Washington University in St. Louis, One Brookings Drive, Campus Box 1097, St. Louis, MO 63130
- Computational and Molecular Biophysics Program, Washington University in St. Louis, One Brookings Drive, Campus Box 1097, St. Louis, MO 63130
| | - Scott L. Crick
- Department of Biomedical Engineering, Washington University in St. Louis, One Brookings Drive, Campus Box 1097, St. Louis, MO 63130
| | - Rohit V. Pappu
- Department of Biomedical Engineering, Washington University in St. Louis, One Brookings Drive, Campus Box 1097, St. Louis, MO 63130
- Center for Computational Biology, Washington University in St. Louis, One Brookings Drive, Campus Box 1097, St. Louis, MO 63130
- Computational and Molecular Biophysics Program, Washington University in St. Louis, One Brookings Drive, Campus Box 1097, St. Louis, MO 63130
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Massella A, Gusciglio M, D'Intino G, Sivilia S, Ferraro L, Calzà L, Giardino L. Gabapentin treatment improves motor coordination in a mice model of progressive ataxia. Brain Res 2009; 1301:135-42. [DOI: 10.1016/j.brainres.2009.09.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2009] [Revised: 08/27/2009] [Accepted: 09/01/2009] [Indexed: 02/07/2023]
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42
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Thakur AK, Jayaraman M, Mishra R, Thakur M, Chellgren VM, Byeon IJ, Anjum DH, Kodali R, Creamer TP, Conway JF, M.Gronenborn A, Wetzel R. Polyglutamine disruption of the huntingtin exon 1 N terminus triggers a complex aggregation mechanism. Nat Struct Mol Biol 2009; 16:380-9. [PMID: 19270701 PMCID: PMC2706102 DOI: 10.1038/nsmb.1570] [Citation(s) in RCA: 349] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2008] [Accepted: 01/30/2009] [Indexed: 11/08/2022]
Abstract
Simple polyglutamine (polyQ) peptides aggregate in vitro via a nucleated growth pathway directly yielding amyloid-like aggregates. We show here that the 17-amino-acid flanking sequence (HTT(NT)) N-terminal to the polyQ in the toxic huntingtin exon 1 fragment imparts onto this peptide a complex alternative aggregation mechanism. In isolation, the HTT(NT) peptide is a compact coil that resists aggregation. When polyQ is fused to this sequence, it induces in HTT(NT), in a repeat-length dependent fashion, a more extended conformation that greatly enhances its aggregation into globular oligomers with HTT(NT) cores and exposed polyQ. In a second step, a new, amyloid-like aggregate is formed with a core composed of both HTT(NT) and polyQ. The results indicate unprecedented complexity in how primary sequence controls aggregation within a substantially disordered peptide and have implications for the molecular mechanism of Huntington's disease.
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Affiliation(s)
- Ashwani K. Thakur
- Department of Structural Biology, University of Pittsburgh School of Medicine, Biomedical Sciences Tower 3, 3501 Fifth Avenue, Pittsburgh PA 15260
- Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Biomedical Sciences Tower 3, 3501 Fifth Avenue, Pittsburgh PA 15260
| | - Murali Jayaraman
- Department of Structural Biology, University of Pittsburgh School of Medicine, Biomedical Sciences Tower 3, 3501 Fifth Avenue, Pittsburgh PA 15260
- Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Biomedical Sciences Tower 3, 3501 Fifth Avenue, Pittsburgh PA 15260
| | - Rakesh Mishra
- Department of Structural Biology, University of Pittsburgh School of Medicine, Biomedical Sciences Tower 3, 3501 Fifth Avenue, Pittsburgh PA 15260
- Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Biomedical Sciences Tower 3, 3501 Fifth Avenue, Pittsburgh PA 15260
| | - Monika Thakur
- Department of Structural Biology, University of Pittsburgh School of Medicine, Biomedical Sciences Tower 3, 3501 Fifth Avenue, Pittsburgh PA 15260
- Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Biomedical Sciences Tower 3, 3501 Fifth Avenue, Pittsburgh PA 15260
| | - Veronique M. Chellgren
- Department of Molecular and Cellular Biochemistry, University of Kentucky, 741 South Limestone St., B265, Lexington KY 40536
| | - In-Ja Byeon
- Department of Structural Biology, University of Pittsburgh School of Medicine, Biomedical Sciences Tower 3, 3501 Fifth Avenue, Pittsburgh PA 15260
| | - Dalaver H. Anjum
- Department of Structural Biology, University of Pittsburgh School of Medicine, Biomedical Sciences Tower 3, 3501 Fifth Avenue, Pittsburgh PA 15260
| | - Ravindra Kodali
- Department of Structural Biology, University of Pittsburgh School of Medicine, Biomedical Sciences Tower 3, 3501 Fifth Avenue, Pittsburgh PA 15260
- Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Biomedical Sciences Tower 3, 3501 Fifth Avenue, Pittsburgh PA 15260
| | - Trevor P. Creamer
- Department of Molecular and Cellular Biochemistry, University of Kentucky, 741 South Limestone St., B265, Lexington KY 40536
| | - James F. Conway
- Department of Structural Biology, University of Pittsburgh School of Medicine, Biomedical Sciences Tower 3, 3501 Fifth Avenue, Pittsburgh PA 15260
| | - Angela M.Gronenborn
- Department of Structural Biology, University of Pittsburgh School of Medicine, Biomedical Sciences Tower 3, 3501 Fifth Avenue, Pittsburgh PA 15260
| | - Ronald Wetzel
- Department of Structural Biology, University of Pittsburgh School of Medicine, Biomedical Sciences Tower 3, 3501 Fifth Avenue, Pittsburgh PA 15260
- Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Biomedical Sciences Tower 3, 3501 Fifth Avenue, Pittsburgh PA 15260
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Williams AJ, Knutson TM, Colomer Gould VF, Paulson HL. In vivo suppression of polyglutamine neurotoxicity by C-terminus of Hsp70-interacting protein (CHIP) supports an aggregation model of pathogenesis. Neurobiol Dis 2009; 33:342-53. [PMID: 19084066 PMCID: PMC2662361 DOI: 10.1016/j.nbd.2008.10.016] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2008] [Accepted: 10/23/2008] [Indexed: 01/13/2023] Open
Abstract
Perturbations in neuronal protein homeostasis likely contribute to disease pathogenesis in polyglutamine (polyQ) neurodegenerative disorders. Here we provide evidence that the co-chaperone and ubiquitin ligase, CHIP (C-terminus of Hsp70-interacting protein), is a central component to the homeostatic mechanisms countering toxic polyQ proteins in the brain. Genetic reduction or elimination of CHIP accelerates disease in transgenic mice expressing polyQ-expanded ataxin-3, the disease protein in Spinocerebellar Ataxia Type 3 (SCA3). In parallel, CHIP reduction markedly increases the level of ataxin-3 microaggregates, which partition in the soluble fraction of brain lysates yet are resistant to dissociation with denaturing detergent, and which precede the appearance of inclusions. The level of microaggregates in the CNS, but not of ataxin-3 monomer, correlates with disease severity. Additional cell-based studies suggest that either of two quality control ubiquitin ligases, CHIP or E4B, can reduce steady state levels of expanded, but not wild-type, ataxin-3. Our results support an aggregation model of polyQ disease pathogenesis in which ataxin-3 microaggregates are a neurotoxic species, and suggest that enhancing CHIP activity is a possible route to therapy for SCA3 and other polyQ diseases.
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Affiliation(s)
- Aislinn J Williams
- Graduate Program in Neuroscience and Medical Scientist Training Program, University of Iowa, 2206 MERF, Iowa City, IA 52242, USA.
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44
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Williams AJ, Paulson HL. Polyglutamine neurodegeneration: protein misfolding revisited. Trends Neurosci 2008; 31:521-8. [PMID: 18778858 PMCID: PMC2580745 DOI: 10.1016/j.tins.2008.07.004] [Citation(s) in RCA: 272] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2008] [Revised: 07/30/2008] [Accepted: 07/31/2008] [Indexed: 01/01/2023]
Abstract
Polyglutamine diseases are a major cause of neurodegeneration worldwide. Recent studies highlight the importance of protein quality control mechanisms in regulating polyglutamine-induced toxicity. Here we discuss a model of disease pathogenesis that integrates current understanding of the role of protein folding in polyglutamine disease with emerging evidence that alterations in native protein interactions contribute to toxicity. We also incorporate new findings on other age-related neurodegenerative diseases in an effort to explain how protein aggregation and normal aging processes might be involved in polyglutamine disease pathogenesis.
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Affiliation(s)
- Aislinn J. Williams
- Program in Neuroscience and Medical Scientist Training Program, University of Iowa, 2206 MERF, Iowa City, IA 52242,
- Department of Neurology, University of Michigan, 4188 BSRB, 109 Zina Pitcher Place, Ann Arbor, MI 48108,
| | - Henry L. Paulson
- Department of Neurology, University of Michigan, 4188 BSRB, 109 Zina Pitcher Place, Ann Arbor, MI 48108,
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45
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Inclusion bodies: Specificity in their aggregation process and amyloid-like structure. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2008; 1783:1815-25. [DOI: 10.1016/j.bbamcr.2008.06.007] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2007] [Revised: 05/28/2008] [Accepted: 06/03/2008] [Indexed: 01/10/2023]
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46
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Truant R, Atwal RS, Desmond C, Munsie L, Tran T. Huntington's disease: revisiting the aggregation hypothesis in polyglutamine neurodegenerative diseases. FEBS J 2008; 275:4252-62. [PMID: 18637947 DOI: 10.1111/j.1742-4658.2008.06561.x] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
After the successful cloning of the first gene for a polyglutamine disease in 1991, the expanded polyglutamine tract in the nine polyglutamine disease proteins became an obvious therapeutic target. Early hypotheses were that misfolded, precipitated protein could be a universal pathogenic mechanism. However, new data are accumulating on Huntington's disease and other polyglutamine diseases that appear to contradict the toxic aggregate hypothesis. Recent data suggest that the toxic species of protein in these diseases may be soluble mutant conformers, and that the protein context of expanded polyglutamine is critical to understanding disease specificity. Here we discuss recent publications that define other important therapeutic targets for polyglutamine-mediated neurodegeneration related to the context of the expanded polyglutamine tract in the disease protein.
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Affiliation(s)
- Ray Truant
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada.
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47
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Hinz J, Gierasch LM, Ignatova Z. Orthogonal cross-seeding: an approach to explore protein aggregates in living cells. Biochemistry 2008; 47:4196-200. [PMID: 18330996 PMCID: PMC2896251 DOI: 10.1021/bi800002j] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Protein aggregation is associated with the pathology of many diseases, especially neurodegenerative diseases. A variety of structurally polymorphic aggregates or preaggregates including amyloid fibrils is accessible to any aggregating protein. Preaggregates are now believed to be the toxic culprits in pathologies rather than mature aggregates. Although clearly valuable, understanding the mechanism of formation and the structural characteristics of these prefibrillar species is currently lacking. We report here a simple new approach to map the nature of the aggregate core of transient aggregated species directly in the cell. The method is conceptually based on the highly discriminating ability of aggregates to recruit new monomeric species with equivalent molecular structure. Different soluble segments comprising parts of an amyloidogenic protein were transiently pulse-expressed in a tightly controlled, time-dependent manner along with the parent aggregating full-length protein, and their recruitment into the insoluble aggregate was monitored immunochemically. We used this approach to determine the nature of the aggregate core of the metastable aggregate species formed during the course of aggregation of a chimera containing a long polyglutamine repeat tract in a bacterial host. Strikingly, we found that different segments of the full-length protein dominated the aggregate core at different times during the course of aggregation. In its simplicity, the approach is also potentially amenable to screen also for compounds that can reshape the aggregate core and induce the formation of alternative nonamyloidogenic species.
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Affiliation(s)
- Justyna Hinz
- Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Lila M. Gierasch
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts 01003
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003
| | - Zoya Ignatova
- Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
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48
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Ignatova Z, Thakur AK, Wetzel R, Gierasch LM. In-cell aggregation of a polyglutamine-containing chimera is a multistep process initiated by the flanking sequence. J Biol Chem 2007; 282:36736-43. [PMID: 17942400 PMCID: PMC2892112 DOI: 10.1074/jbc.m703682200] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Toxicity in amyloid diseases is intimately linked to the nature of aggregates, with early oligomeric species believed to be more cytotoxic than later fibrillar aggregates. Yet mechanistic understanding of how aggregating species evolve with time is currently lacking. We have explored the aggregation process of a chimera composed of a globular protein (cellular retinoic acid-binding protein, CRABP) and huntingtin exon 1 with polyglutamine tracts either above (Q53) or below (Q20) the pathological threshold using Escherichia coli cells as a model intracellular environment. Previously we showed that fusion of the huntingtin exon 1 sequence with >40Q led to structural perturbation and decreased stability of CRABP (Ignatova, Z., and Gierasch, L. M. (2006) J. Biol. Chem. 281, 12959-12967). Here we report that the Q53 chimera aggregates in cells via a multistep process: early stage aggregates are spherical and detergent-soluble, characteristics of prefibrillar aggregates, and appear to be dominated structurally by CRABP, in that they can promote aggregation of a CRABP variant but not oligoglutamine aggregation, and the CRABP domain is relatively sequestered based on its protection from proteolysis. Late stage aggregates appear to be dominated by polyGln; they are fibrillar, detergent-resistant, capable of seeding aggregation of oligoglutamine but not the CRABP variant, and show relative protection of the polyglutamine-exon1 domain from proteolysis. These results point to an evolution of the dominant sequences in intracellular aggregates and may provide molecular insight into origins of toxic prefibrillar aggregates.
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Affiliation(s)
- Zoya Ignatova
- Max Planck Institute of Biochemistry, Am Klopferspitz 18, Martinsried 82152, Germany
- Departments of Biochemistry & Molecular Biology and Chemistry, University of Massachusetts-Amherst, Amherst, Massachusetts 01003
| | - Ashwani K. Thakur
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15206
| | - Ronald Wetzel
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15206
| | - Lila M. Gierasch
- Departments of Biochemistry & Molecular Biology and Chemistry, University of Massachusetts-Amherst, Amherst, Massachusetts 01003
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49
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Rich T, Varadaraj A. Ataxin-1 fusion partners alter polyQ lethality and aggregation. PLoS One 2007; 2:e1014. [PMID: 17925862 PMCID: PMC1995763 DOI: 10.1371/journal.pone.0001014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2007] [Accepted: 09/19/2007] [Indexed: 01/07/2023] Open
Abstract
Intranuclear inclusion bodies (IBs) are the histopathologic markers of multiple protein folding diseases. IB formation has been extensively studied using fluorescent fusion products of pathogenic polyglutamine (polyQ) expressing proteins. These studies have been informative in determining the cellular targets of expanded polyQ protein as well as the methods by which cells rid themselves of IBs. The experimental thrust has been to intervene in the process of polyQ aggregation in an attempt to alleviate cytotoxicity. However new data argues against the notion that polyQ aggregation and cytotoxicity are inextricably linked processes. We reasoned that changing the protein context of a disease causing polyQ protein could accelerate its precipitation as an IB, potentially reducing its cytotoxicity. Our experimental strategy simply exploited the fact that conjoined proteins influence each others folding and aggregation properties. We fused a full-length pathogenic ataxin-1 construct to fluorescent tags (GFP and DsRed1-E5) that exist at different oligomeric states. The spectral properties of the DsRed1-E5-ataxin-1 transfectants had the additional advantage of allowing us to correlate fluorochrome maturation with cytotoxicity. Each fusion protein expressed a distinct cytotoxicity and IB morphology. Flow cytometric analyses of transfectants expressing the greatest fluorescent signals revealed that the DsRed1-E5-ataxin-1 fusion was more toxic than GFP fused ataxin-1 (31.8±4.5% cell death versus 12.85±3%), although co-transfection with the GFP fusion inhibited maturation of the DsRed1-E5 fluorochrome and diminished the toxicity of the DsRed1-E5-ataxin-1 fusion. These data show that polyQ driven aggregation can be influenced by fusion partners to generate species with different toxic properties and provide new opportunities to study IB aggregation, maturation and lethality.
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Affiliation(s)
- Tina Rich
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom.
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50
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Darnell G, Orgel JPRO, Pahl R, Meredith SC. Flanking polyproline sequences inhibit beta-sheet structure in polyglutamine segments by inducing PPII-like helix structure. J Mol Biol 2007; 374:688-704. [PMID: 17945257 DOI: 10.1016/j.jmb.2007.09.023] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2007] [Revised: 09/05/2007] [Accepted: 09/07/2007] [Indexed: 10/22/2022]
Abstract
Polyglutamine (poly(Q)) expansion is associated with protein aggregation into beta-sheet amyloid fibrils and neuronal cytotoxicity. In the mutant poly(Q) protein huntingtin, associated with Huntington's disease, both aggregation and cytotoxicity may be abrogated by a polyproline (poly(P)) domain flanking the C terminus of the poly(Q) region. To understand structural changes that may occur with the addition of the poly(P) sequence, we synthesized poly(Q) peptides with 3-15 glutamine residues and a corresponding set of poly(Q) peptides flanked on the C terminus by 11 proline residues (poly(Q)-poly(P)), as occurs in the huntingtin sequence. The shorter soluble poly(Q) peptides (three or six glutamine residues) showed polyproline type II-like (PPII)-like helix conformation when examined by circular dichroism spectroscopy and were monomers as judged by size-exclusion chromatography (SEC), while the longer poly(Q) peptides (nine or 15 glutamine residues) showed a beta-sheet conformation by CD and defined oligomers by SEC. Soluble poly(Q)-poly(P) peptides showed PPII-like content but SEC showed poorly defined, overlapping oligomeric peaks, and as judged by CD these peptides retained significant PPII-like structure with increasing poly(Q) length. More importantly, addition of the poly(P) domain increased the threshold for fibril formation to approximately 15 glutamine residues. X-ray diffraction, electron microscopy, and film CD showed that, while poly(Q) peptides with >or=6 glutamine residues formed beta-sheet-rich fibrils, only the longest poly(Q)-poly(P) peptide (15 glutamine residues) did so. From these and other observations, we propose that poly(Q) domains exist in a "tug-of-war" between two conformations, a PPII-like helix and a beta-sheet, while the poly(P) domain is conformationally constrained into a proline type II helix (PPII). Addition of poly(P) to the C terminus of a poly(Q) domain induces a PPII-like structure, which opposes the aggregation-prone beta-sheet. These structural observations may shed light on the threshold phenomenon of poly(Q) aggregation, and support the hypothesized evolution of "protective" poly(P) tracts adjacent to poly(Q) aggregation domains.
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Affiliation(s)
- Gregory Darnell
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL 60637, USA
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