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Tandon S, Aggarwal P, Sarkar S. Polyglutamine disorders: Pathogenesis and potential drug interventions. Life Sci 2024; 344:122562. [PMID: 38492921 DOI: 10.1016/j.lfs.2024.122562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 02/27/2024] [Accepted: 03/13/2024] [Indexed: 03/18/2024]
Abstract
Polyglutamine/poly(Q) diseases are a group nine hereditary neurodegenerative disorders caused due to abnormally expanded stretches of CAG trinucleotide in functionally distinct genes. All human poly(Q) diseases are characterized by the formation of microscopically discernable poly(Q) positive aggregates, the inclusion bodies. These toxic inclusion bodies are responsible for the impairment of several cellular pathways such as autophagy, transcription, cell death, etc., that culminate in disease manifestation. Although, these diseases remain largely without treatment, extensive research has generated mounting evidences that various events of poly(Q) pathogenesis can be developed as potential drug targets. The present review article briefly discusses the key events of disease pathogenesis, model system-based investigations that support the development of effective therapeutic interventions against pathogenesis of human poly(Q) disorders, and a comprehensive list of pharmacological and bioactive compounds that have been experimentally shown to alleviate poly(Q)-mediated neurotoxicity. Interestingly, due to the common cause of pathogenesis, all poly(Q) diseases share etiology, thus, findings from one disease can be potentially extrapolated to other poly(Q) diseases as well.
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Affiliation(s)
- Shweta Tandon
- Department of Genetics, University of Delhi South Campus, Benito Juarez Road, New Delhi 110021, India
| | - Prerna Aggarwal
- Department of Genetics, University of Delhi South Campus, Benito Juarez Road, New Delhi 110021, India
| | - Surajit Sarkar
- Department of Genetics, University of Delhi South Campus, Benito Juarez Road, New Delhi 110021, India.
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2
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Pereira Sena P, Weber JJ, Bayezit S, Saup R, Incebacak Eltemur RD, Li X, Velic A, Jung J, Macek B, Nguyen HP, Riess O, Schmidt T. Implications of specific lysine residues within ataxin-3 for the molecular pathogenesis of Machado-Joseph disease. Front Mol Neurosci 2023; 16:1133271. [PMID: 37273907 PMCID: PMC10235640 DOI: 10.3389/fnmol.2023.1133271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Accepted: 05/03/2023] [Indexed: 06/06/2023] Open
Abstract
Lysine residues are one of the main sites for posttranslational modifications of proteins, and lysine ubiquitination of the Machado-Joseph disease protein ataxin-3 is implicated in its cellular function and polyglutamine expansion-dependent toxicity. Despite previously undertaken efforts, the individual roles of specific lysine residues of the ataxin-3 sequence are not entirely understood and demand further analysis. By retaining single lysine residues of otherwise lysine-free wild-type and polyglutamine-expanded ataxin-3, we assessed the effects of a site-limited modifiability on ataxin-3 protein levels, aggregation propensity, localization, and stability. We confirmed earlier findings that levels of lysine-free ataxin-3 are reduced due to its decreased stability, which led to a diminished load of SDS-insoluble species of its polyglutamine-expanded form. The isolated presence of several single lysine residues within the N-terminus of polyglutamine-expanded ataxin-3 significantly restored its aggregate levels, with highest fold changes induced by the presence of lysine 8 or lysine 85, respectively. Ataxin-3 lacking all lysine residues presented a slightly increased nuclear localization, which was counteracted by the reintroduction of lysine 85, whereas presence of either lysine 8 or lysine 85 led to a significantly higher ataxin-3 stability. Moreover, lysine-free ataxin-3 showed increased toxicity and binding to K48-linked polyubiquitin chains, whereas the reintroduction of lysine 85, located between the ubiquitin-binding sites 1 and 2 of ataxin-3, normalized its binding affinity. Overall, our data highlight the relevance of lysine residues 8 and 85 of ataxin-3 and encourage further analyses, to evaluate the potential of modulating posttranslational modifications of these sites for influencing pathophysiological characteristics of the Machado-Joseph disease protein.
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Affiliation(s)
- Priscila Pereira Sena
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
| | - Jonasz Jeremiasz Weber
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
- Department of Human Genetics, Ruhr University Bochum, Bochum, Germany
| | - Sercan Bayezit
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
| | - Rafael Saup
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
| | - Rana Dilara Incebacak Eltemur
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
- Department of Human Genetics, Ruhr University Bochum, Bochum, Germany
| | - Xiaoling Li
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
| | - Ana Velic
- Proteome Center Tübingen, University of Tübingen, Tübingen, Germany
| | - Jaqueline Jung
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
| | - Boris Macek
- Proteome Center Tübingen, University of Tübingen, Tübingen, Germany
| | - Huu Phuc Nguyen
- Department of Human Genetics, Ruhr University Bochum, Bochum, Germany
| | - Olaf Riess
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
| | - Thorsten Schmidt
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
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3
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Short Linear Motifs in Colorectal Cancer Interactome and Tumorigenesis. Cells 2022; 11:cells11233739. [PMID: 36496998 PMCID: PMC9737320 DOI: 10.3390/cells11233739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 11/16/2022] [Accepted: 11/21/2022] [Indexed: 11/25/2022] Open
Abstract
Colorectal tumorigenesis is driven by alterations in genes and proteins responsible for cancer initiation, progression, and invasion. This multistage process is based on a dense network of protein-protein interactions (PPIs) that become dysregulated as a result of changes in various cell signaling effectors. PPIs in signaling and regulatory networks are known to be mediated by short linear motifs (SLiMs), which are conserved contiguous regions of 3-10 amino acids within interacting protein domains. SLiMs are the minimum sequences required for modulating cellular PPI networks. Thus, several in silico approaches have been developed to predict and analyze SLiM-mediated PPIs. In this review, we focus on emerging evidence supporting a crucial role for SLiMs in driver pathways that are disrupted in colorectal cancer (CRC) tumorigenesis and related PPI network alterations. As a result, SLiMs, along with short peptides, are attracting the interest of researchers to devise small molecules amenable to be used as novel anti-CRC targeted therapies. Overall, the characterization of SLiMs mediating crucial PPIs in CRC may foster the development of more specific combined pharmacological approaches.
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Johnson SL, Tsou WL, Prifti MV, Harris AL, Todi SV. A survey of protein interactions and posttranslational modifications that influence the polyglutamine diseases. Front Mol Neurosci 2022; 15:974167. [PMID: 36187346 PMCID: PMC9515312 DOI: 10.3389/fnmol.2022.974167] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 07/27/2022] [Indexed: 01/20/2023] Open
Abstract
The presence and aggregation of misfolded proteins has deleterious effects in the nervous system. Among the various diseases caused by misfolded proteins is the family of the polyglutamine (polyQ) disorders. This family comprises nine members, all stemming from the same mutation—the abnormal elongation of a polyQ repeat in nine different proteins—which causes protein misfolding and aggregation, cellular dysfunction and disease. While it is the same type of mutation that causes them, each disease is distinct: it is influenced by regions and domains that surround the polyQ repeat; by proteins with which they interact; and by posttranslational modifications they receive. Here, we overview the role of non-polyQ regions that control the pathogenicity of the expanded polyQ repeat. We begin by introducing each polyQ disease, the genes affected, and the symptoms experienced by patients. Subsequently, we provide a survey of protein-protein interactions and posttranslational modifications that regulate polyQ toxicity. We conclude by discussing shared processes and pathways that bring some of the polyQ diseases together and may serve as common therapeutic entry points for this family of incurable disorders.
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Affiliation(s)
- Sean L. Johnson
- Department of Pharmacology, Wayne State University, Detroit, MI, United States
| | - Wei-Ling Tsou
- Department of Pharmacology, Wayne State University, Detroit, MI, United States
| | - Matthew V. Prifti
- Department of Pharmacology, Wayne State University, Detroit, MI, United States
| | - Autumn L. Harris
- Department of Pharmacology, Wayne State University, Detroit, MI, United States
- Maximizing Access to Research Careers (MARC) Program, Wayne State University, Detroit, MI, United States
| | - Sokol V. Todi
- Department of Pharmacology, Wayne State University, Detroit, MI, United States
- Maximizing Access to Research Careers (MARC) Program, Wayne State University, Detroit, MI, United States
- Department of Neurology, Wayne State University, Detroit, MI, United States
- *Correspondence: Sokol V. Todi,
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5
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Gupta R, Sahu M, Srivastava D, Tiwari S, Ambasta RK, Kumar P. Post-translational modifications: Regulators of neurodegenerative proteinopathies. Ageing Res Rev 2021; 68:101336. [PMID: 33775891 DOI: 10.1016/j.arr.2021.101336] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 03/10/2021] [Accepted: 03/22/2021] [Indexed: 12/14/2022]
Abstract
One of the hallmark features in the neurodegenerative disorders (NDDs) is the accumulation of aggregated and/or non-functional protein in the cellular milieu. Post-translational modifications (PTMs) are an essential regulator of non-functional protein aggregation in the pathogenesis of NDDs. Any alteration in the post-translational mechanism and the protein quality control system, for instance, molecular chaperone, ubiquitin-proteasome system, autophagy-lysosomal degradation pathway, enhances the accumulation of misfolded protein, which causes neuronal dysfunction. Post-translational modification plays many roles in protein turnover rate, accumulation of aggregate and can also help in the degradation of disease-causing toxic metabolites. PTMs such as acetylation, glycosylation, phosphorylation, ubiquitination, palmitoylation, SUMOylation, nitration, oxidation, and many others regulate protein homeostasis, which includes protein structure, functions and aggregation propensity. Different studies demonstrated the involvement of PTMs in the regulation of signaling cascades such as PI3K/Akt/GSK3β, MAPK cascade, AMPK pathway, and Wnt signaling pathway in the pathogenesis of NDDs. Further, mounting evidence suggests that targeting different PTMs with small chemical molecules, which acts as an inhibitor or activator, reverse misfolded protein accumulation and thus enhances the neuroprotection. Herein, we briefly discuss the protein aggregation and various domain structures of different proteins involved in the NDDs, indicating critical amino acid residues where PTMs occur. We also describe the implementation and involvement of various PTMs on signaling cascade and cellular processes in NDDs. Lastly, we implement our current understanding of the therapeutic importance of PTMs in neurodegeneration, along with emerging techniques targeting various PTMs.
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6
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Wang Y, Wang F. Post-Translational Modifications of Deubiquitinating Enzymes: Expanding the Ubiquitin Code. Front Pharmacol 2021; 12:685011. [PMID: 34177595 PMCID: PMC8224227 DOI: 10.3389/fphar.2021.685011] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 05/25/2021] [Indexed: 12/14/2022] Open
Abstract
Post-translational modifications such as ubiquitination play important regulatory roles in several biological processes in eukaryotes. This process could be reversed by deubiquitinating enzymes (DUBs), which remove conjugated ubiquitin molecules from target substrates. Owing to their role as essential enzymes in regulating all ubiquitin-related processes, the abundance, localization, and catalytic activity of DUBs are tightly regulated. Dysregulation of DUBs can cause dramatic physiological consequences and a variety of disorders such as cancer, and neurodegenerative and inflammatory diseases. Multiple factors, such as transcription and translation of associated genes, and the presence of accessory domains, binding proteins, and inhibitors have been implicated in several aspects of DUB regulation. Beyond this level of regulation, emerging studies show that the function of DUBs can be regulated by a variety of post-translational modifications, which significantly affect the abundance, localization, and catalytic activity of DUBs. The most extensively studied post-translational modification of DUBs is phosphorylation. Besides phosphorylation, ubiquitination, SUMOylation, acetylation, oxidation, and hydroxylation are also reported in DUBs. In this review, we summarize the current knowledge on the regulatory effects of post-translational modifications of DUBs.
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Affiliation(s)
- Yanfeng Wang
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Feng Wang
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, Beijing, China
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7
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Sowa AS, Popova TG, Harmuth T, Weber JJ, Pereira Sena P, Schmidt J, Hübener-Schmid J, Schmidt T. Neurodegenerative phosphoprotein signaling landscape in models of SCA3. Mol Brain 2021; 14:57. [PMID: 33741019 PMCID: PMC7980345 DOI: 10.1186/s13041-020-00723-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 12/28/2020] [Indexed: 01/01/2023] Open
Abstract
Spinocerebellar ataxia type 3 (SCA3) is a rare neurodegenerative disorder resulting from an aberrant expansion of a polyglutamine stretch in the ataxin-3 protein and subsequent neuronal death. The underlying intracellular signaling pathways are currently unknown. We applied the Reverse-phase Protein MicroArray (RPMA) technology to assess the levels of 50 signaling proteins (in phosphorylated and total forms) using three in vitro and in vivo models expressing expanded ataxin-3: (i) human embryonic kidney (HEK293T) cells stably transfected with human ataxin-3 constructs, (ii) mouse embryonic fibroblasts (MEF) from SCA3 transgenic mice, and (iii) whole brains from SCA3 transgenic mice. All three models demonstrated a high degree of similarity sharing a subset of phosphorylated proteins involved in the PI3K/AKT/GSK3/mTOR pathway. Expanded ataxin-3 strongly interfered (by stimulation or suppression) with normal ataxin-3 signaling consistent with the pathogenic role of the polyglutamine expansion. In comparison with normal ataxin-3, expanded ataxin-3 caused a pro-survival stimulation of the ERK pathway along with reduced pro-apoptotic and transcriptional responses.
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Affiliation(s)
- Anna S Sowa
- Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Calwerstrasse 7, 72076, Tuebingen, Germany.,Centre for Rare Diseases, University of Tuebingen, 72076, Tuebingen, Germany
| | - Taissia G Popova
- Center for Applied Proteomics and Molecular Medicine, College of Science, George Mason University, Manassas, VA, USA
| | - Tina Harmuth
- Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Calwerstrasse 7, 72076, Tuebingen, Germany.,Centre for Rare Diseases, University of Tuebingen, 72076, Tuebingen, Germany
| | - Jonasz J Weber
- Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Calwerstrasse 7, 72076, Tuebingen, Germany.,Centre for Rare Diseases, University of Tuebingen, 72076, Tuebingen, Germany.,Department of Human Genetics, Ruhr-University Bochum, Universitaetsstrasse 150, 44801, Bochum, Germany
| | - Priscila Pereira Sena
- Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Calwerstrasse 7, 72076, Tuebingen, Germany.,Centre for Rare Diseases, University of Tuebingen, 72076, Tuebingen, Germany
| | - Jana Schmidt
- Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Calwerstrasse 7, 72076, Tuebingen, Germany.,Centre for Rare Diseases, University of Tuebingen, 72076, Tuebingen, Germany
| | - Jeannette Hübener-Schmid
- Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Calwerstrasse 7, 72076, Tuebingen, Germany.,Centre for Rare Diseases, University of Tuebingen, 72076, Tuebingen, Germany
| | - Thorsten Schmidt
- Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Calwerstrasse 7, 72076, Tuebingen, Germany. .,Centre for Rare Diseases, University of Tuebingen, 72076, Tuebingen, Germany.
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8
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Regulation of Deubiquitinating Enzymes by Post-Translational Modifications. Int J Mol Sci 2020; 21:ijms21114028. [PMID: 32512887 PMCID: PMC7312083 DOI: 10.3390/ijms21114028] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 06/01/2020] [Accepted: 06/01/2020] [Indexed: 01/04/2023] Open
Abstract
Ubiquitination and deubiquitination play a critical role in all aspects of cellular processes, and the enzymes involved are tightly regulated by multiple factors including posttranslational modifications like most other proteins. Dysfunction or misregulation of these enzymes could have dramatic physiological consequences, sometimes leading to diseases. Therefore, it is important to have a clear understanding of these regulatory processes. Here, we have reviewed the posttranslational modifications of deubiquitinating enzymes and their consequences on the catalytic activity, stability, abundance, localization, and interaction with the partner proteins.
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9
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Pennuto M, Pandey UB, Polanco MJ. Insulin-like growth factor 1 signaling in motor neuron and polyglutamine diseases: From molecular pathogenesis to therapeutic perspectives. Front Neuroendocrinol 2020; 57:100821. [PMID: 32006533 DOI: 10.1016/j.yfrne.2020.100821] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 01/24/2020] [Accepted: 01/24/2020] [Indexed: 11/19/2022]
Abstract
The pleiotropic peptide insulin-like growth factor 1 (IGF-I) regulates human body homeostasis and cell growth. IGF-I activates two major signaling pathways, namely phosphoinositide-3-kinase (PI3K)/protein kinase B (PKB/Akt) and Ras/extracellular signal-regulated kinase (ERK), which contribute to brain development, metabolism and function as well as to neuronal maintenance and survival. In this review, we discuss the general and tissue-specific effects of the IGF-I pathways. In addition, we present a comprehensive overview examining the role of IGF-I in neurodegenerative diseases, such as spinal and muscular atrophy, amyotrophic lateral sclerosis, and polyglutamine diseases. In each disease, we analyze the disturbances of the IGF-I pathway, the modification of the disease protein by IGF-I signaling, and the therapeutic strategies based on the use of IGF-I developed to date. Lastly, we highlight present and future considerations in the use of IGF-I for the treatment of these disorders.
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Affiliation(s)
- Maria Pennuto
- Department of Biomedical Sciences (DBS), University of Padova, 35131 Padova, Italy; Veneto Institute of Molecular Medicine (VIMM), Via Orus 2, 35129 Padova, Italy; Padova Neuroscience Center (PNC), 35131 Padova, Italy; Myology Center (CIR-Myo), 35131 Padova, Italy.
| | - Udai Bhan Pandey
- Department of Human Genetics, University of Pittsburgh Graduate School of Public Health, Pittsburgh, PA 15261, USA; Division of Child Neurology, Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA 15224, USA; Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - María José Polanco
- Department of Pharmaceutic and Health Science, University San Pablo CEU, Campus Montepríncipe, 28925 Alcorcón, Madrid, Spain.
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10
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Da Silva JD, Teixeira-Castro A, Maciel P. From Pathogenesis to Novel Therapeutics for Spinocerebellar Ataxia Type 3: Evading Potholes on the Way to Translation. Neurotherapeutics 2019; 16:1009-1031. [PMID: 31691128 PMCID: PMC6985322 DOI: 10.1007/s13311-019-00798-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
Spinocerebellar ataxia type 3 (SCA3), also known as Machado-Joseph disease (MJD), is a neurodegenerative disorder caused by a polyglutamine expansion in the ATXN3 gene. In spite of the identification of a clear monogenic cause 25 years ago, the pathological process still puzzles researchers, impairing prospects for an effective therapy. Here, we propose the disruption of protein homeostasis as the hub of SCA3 pathogenesis, being the molecular mechanisms and cellular pathways that are deregulated in SCA3 downstream consequences of the misfolding and aggregation of ATXN3. Moreover, we attempt to provide a realistic perspective on how the translational/clinical research in SCA3 should evolve. This was based on molecular findings, clinical and epidemiological characteristics, studies of proposed treatments in other conditions, and how that information is essential for their (re-)application in SCA3. This review thus aims i) to critically evaluate the current state of research on SCA3, from fundamental to translational and clinical perspectives; ii) to bring up the current key questions that remain unanswered in this disorder; and iii) to provide a frame on how those answers should be pursued.
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Affiliation(s)
- Jorge Diogo Da Silva
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Andreia Teixeira-Castro
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Patrícia Maciel
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.
- ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.
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11
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Wiatr K, Piasecki P, Marczak Ł, Wojciechowski P, Kurkowiak M, Płoski R, Rydzanicz M, Handschuh L, Jungverdorben J, Brüstle O, Figlerowicz M, Figiel M. Altered Levels of Proteins and Phosphoproteins, in the Absence of Early Causative Transcriptional Changes, Shape the Molecular Pathogenesis in the Brain of Young Presymptomatic Ki91 SCA3/MJD Mouse. Mol Neurobiol 2019; 56:8168-8202. [PMID: 31201651 PMCID: PMC6834541 DOI: 10.1007/s12035-019-01643-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 05/10/2019] [Indexed: 12/19/2022]
Abstract
Spinocerebellar ataxia type 3 (SCA3/MJD) is a polyQ neurodegenerative disease where the presymptomatic phase of pathogenesis is unknown. Therefore, we investigated the molecular network of transcriptomic and proteomic triggers in young presymptomatic SCA3/MJD brain from Ki91 knock-in mouse. We found that transcriptional dysregulations resulting from mutant ataxin-3 are not occurring in young Ki91 mice, while old Ki91 mice and also postmitotic patient SCA3 neurons demonstrate the late transcriptomic changes. Unlike the lack of early mRNA changes, we have identified numerous early changes of total proteins and phosphoproteins in 2-month-old Ki91 mouse cortex and cerebellum. We discovered the network of processes in presymptomatic SCA3 with three main groups of disturbed processes comprising altered proteins: (I) modulation of protein levels and DNA damage (Pabpc1, Ddb1, Nedd8), (II) formation of neuronal cellular structures (Tubb3, Nefh, p-Tau), and (III) neuronal function affected by processes following perturbed cytoskeletal formation (Mt-Co3, Stx1b, p-Syn1). Phosphoproteins downregulate in the young Ki91 mouse brain and their phosphosites are associated with kinases that interact with ATXN3 such as casein kinase, Camk2, and kinases controlled by another Atxn3 interactor p21 such as Gsk3, Pka, and Cdk kinases. We conclude that the onset of SCA3 pathology occurs without altered transcript level and is characterized by changed levels of proteins responsible for termination of translation, DNA damage, spliceosome, and protein phosphorylation. This disturbs global cellular processes such as cytoskeleton and transport of vesicles and mitochondria along axons causing energy deficit and neurodegeneration also manifesting in an altered level of transcripts at later ages.
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Affiliation(s)
- Kalina Wiatr
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Z. Noskowskiego 12/14, 61-704, Poznań, Poland
| | - Piotr Piasecki
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Z. Noskowskiego 12/14, 61-704, Poznań, Poland
| | - Łukasz Marczak
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Z. Noskowskiego 12/14, 61-704, Poznań, Poland
| | - Paweł Wojciechowski
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Z. Noskowskiego 12/14, 61-704, Poznań, Poland.,Institute of Computing Science, Poznan University of Technology, Poznań, Poland
| | - Małgorzata Kurkowiak
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Z. Noskowskiego 12/14, 61-704, Poznań, Poland
| | - Rafał Płoski
- Department of Medical Genetics, Medical University of Warsaw, Warsaw, Poland
| | | | - Luiza Handschuh
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Z. Noskowskiego 12/14, 61-704, Poznań, Poland
| | - Johannes Jungverdorben
- Institute of Reconstructive Neurobiology, LIFE & BRAIN Center, University of Bonn School of Medicine & University Hospital Bonn, 53127, Bonn, Germany
| | - Oliver Brüstle
- Institute of Reconstructive Neurobiology, LIFE & BRAIN Center, University of Bonn School of Medicine & University Hospital Bonn, 53127, Bonn, Germany
| | - Marek Figlerowicz
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Z. Noskowskiego 12/14, 61-704, Poznań, Poland
| | - Maciej Figiel
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Z. Noskowskiego 12/14, 61-704, Poznań, Poland.
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12
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Matos CA, de Almeida LP, Nóbrega C. Machado-Joseph disease/spinocerebellar ataxia type 3: lessons from disease pathogenesis and clues into therapy. J Neurochem 2018; 148:8-28. [PMID: 29959858 DOI: 10.1111/jnc.14541] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 06/05/2018] [Accepted: 06/27/2018] [Indexed: 12/25/2022]
Abstract
Machado-Joseph disease (MJD), also known as spinocerebellar ataxia type 3 (SCA3), is an incurable disorder, widely regarded as the most common form of spinocerebellar ataxia in the world. MJD/SCA3 arises from mutation of the ATXN3 gene, but this simple monogenic cause contrasts with the complexity of the pathogenic mechanisms that are currently admitted to underlie neuronal dysfunction and death. The aberrantly expanded protein product - ataxin-3 - is known to aggregate and generate toxic species that disrupt several cell systems, including autophagy, proteostasis, transcription, mitochondrial function and signalling. Over the years, research into putative therapeutic approaches has often been devoted to the development of strategies that counteract disease at different stages of cellular pathogenesis. Silencing the pathogenic protein, blocking aggregation, inhibiting toxic proteolytic processing and counteracting dysfunctions of the cellular systems affected have yielded promising ameliorating results in studies with cellular and animal models. The current review analyses the available studies dedicated to the investigation of MJD/SCA3 pathogenesis and the exploration of possible therapeutic strategies, focusing primarily on gene therapy and pharmacological approaches rooted on the molecular and cellular mechanisms of disease.
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Affiliation(s)
- Carlos A Matos
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal.,Institute for Interdisciplinary Research, University of Coimbra, Coimbra, Portugal
| | - Luís Pereira de Almeida
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal.,Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal
| | - Clévio Nóbrega
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal.,Department of Biomedical Sciences and Medicine, University of Algarve, Coimbra, Portugal.,Centre for Biomedical Research (CBMR), University of Algarve, Coimbra, Portugal.,Algarve Biomedical Center (ABC), University of Algarve, Faro, Portugal
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13
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Wan L, Xu K, Chen Z, Tang B, Jiang H. Roles of Post-translational Modifications in Spinocerebellar Ataxias. Front Cell Neurosci 2018; 12:290. [PMID: 30283301 PMCID: PMC6156280 DOI: 10.3389/fncel.2018.00290] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2018] [Accepted: 08/13/2018] [Indexed: 12/17/2022] Open
Abstract
Post-translational modifications (PTMs), including phosphorylation, acetylation, ubiquitination, SUMOylation, etc., of proteins can modulate protein properties such as intracellular distribution, activity, stability, aggregation, and interactions. Therefore, PTMs are vital regulatory mechanisms for multiple cellular processes. Spinocerebellar ataxias (SCAs) are hereditary, heterogeneous, neurodegenerative diseases for which the primary manifestation involves ataxia. Because the pathogenesis of most SCAs is correlated with mutant proteins directly or indirectly, the PTMs of disease-related proteins might functionally affect SCA development and represent potential therapeutic interventions. Here, we review multiple PTMs related to disease-causing proteins in SCAs pathogenesis and their effects. Furthermore, we discuss these PTMs as potential targets for treating SCAs and describe translational therapies targeting PTMs that have been published.
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Affiliation(s)
- Linlin Wan
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Keqin Xu
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Zhao Chen
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Beisha Tang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Diseases, Central South University, Changsha, China
- Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, China
- Laboratory of Medical Genetics, Central South University, Changsha, China
- Parkinson’s Disease Center of Beijing Institute for Brain Disorders, Beijing, China
- Collaborative Innovation Center for Brain Science, Shanghai, China
- Collaborative Innovation Center for Genetics and Development, Shanghai, China
| | - Hong Jiang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Diseases, Central South University, Changsha, China
- Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, China
- Laboratory of Medical Genetics, Central South University, Changsha, China
- Department of Neurology, Xinjiang Medical University, Ürümqi, China
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14
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Ristic G, Sutton JR, Libohova K, Todi SV. Toxicity and aggregation of the polyglutamine disease protein, ataxin-3 is regulated by its binding to VCP/p97 in Drosophila melanogaster. Neurobiol Dis 2018; 116:78-92. [PMID: 29704548 DOI: 10.1016/j.nbd.2018.04.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 03/26/2018] [Accepted: 04/22/2018] [Indexed: 01/01/2023] Open
Abstract
Among the nine dominantly inherited, age-dependent neurodegenerative diseases caused by abnormal expansion in the polyglutamine (polyQ) repeat of otherwise unrelated proteins is Spinocerebellar Ataxia Type 3 (SCA3). SCA3 is caused by polyQ expansion in the deubiquitinase (DUB), ataxin-3. Molecular sequelae related to SCA3 remain unclear. Here, we sought to understand the role of protein context in SCA3 by focusing on the interaction between this DUB and Valosin-Containing Protein (VCP). VCP is bound directly by ataxin-3 through an arginine-rich area preceding the polyQ repeat. We examined the importance of this interaction in ataxin-3-dependent degeneration in Drosophila melanogaster. Our assays with new isogenic fly lines expressing pathogenic ataxin-3 with an intact or mutated VCP-binding site show that disrupting the ataxin-3-VCP interaction delays the aggregation of the toxic protein in vivo. Importantly, early on flies that express pathogenic ataxin-3 with a mutated VCP-binding site are indistinguishable from flies that do not express any SCA3 protein. Also, reducing levels of VCP through RNA-interference has a similar, protective effect to mutating the VCP-binding site of pathogenic ataxin-3. Based on in vivo pulse-chases, aggregated species of ataxin-3 are highly stable, in a manner independent of VCP-binding. Collectively, our results highlight an important role for the ataxin-3-VCP interaction in SCA3, based on a model that posits a seeding effect from VCP on pathogenic ataxin-3 aggregation and subsequent toxicity.
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Affiliation(s)
- Gorica Ristic
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, MI, USA
| | - Joanna R Sutton
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, MI, USA
| | - Kozeta Libohova
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, MI, USA
| | - Sokol V Todi
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, MI, USA; Department of Neurology, Wayne State University School of Medicine, Detroit, MI, USA.
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15
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Polyglutamine-Independent Features in Ataxin-3 Aggregation and Pathogenesis of Machado-Joseph Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1049:275-288. [PMID: 29427109 DOI: 10.1007/978-3-319-71779-1_14] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The expansion of a trinucleotide (CAG) repeat, translated into a polyglutamine expanded sequence in the protein encoded by the MJD gene, was identified over 20 years ago as the causative mutation in a severe neurodegenerative disorder originally diagnosed in individuals of Portuguese ancestry. This incapacitating disease, called Machado-Joseph disease or spinocebellar ataxia type 3, is integrated into a larger group of neurodegenerative disorders-the polyglutamine expansion disorders-caused by extension of a CAG repeat in the coding sequence of otherwise unrelated genes. These diseases are generally linked with the appearance of intracellular inclusions , which despite having a controversial role in disease appearance and development represent a characteristic common fingerprint in all polyglutamine-related disorders. Although polyglutamine expansion is an obvious trigger for neuronal dysfunction, the role of the different domains of these complex proteins in the function and aggregation properties of the carrier proteins is being uncovered in recent studies. In this review the current knowledge about the structural and functional features of full-length ataxin-3 protein will be discussed. The intrinsic conformational dynamics and interplay between the globular and intrinsically disordered regions of ataxin-3 will be highlighted, and a perspective picture of the role of known ataxin-3 post-translational modifications on regulating ataxin-3 aggregation and function will be drawn.
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16
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Molecular Mechanisms and Cellular Pathways Implicated in Machado-Joseph Disease Pathogenesis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1049:349-367. [PMID: 29427113 DOI: 10.1007/978-3-319-71779-1_18] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Machado-Joseph disease (MJD) is a dominantly inherited disorder originally described in people of Portuguese descent, and associated with the expansion of a CAG tract in the coding region of the causative gene MJD1/ATX3. The CAG repeats range from 10 to 51 in the normal population and from 55 to 87 in SCA3/MJD patients. MJD1 encodes ataxin-3, a protein whose physiological function has been linked to ubiquitin-mediated proteolysis. Despite the identification of the causative mutation, the pathogenic process leading to the neurodegeneration observed in the disease is not yet completely understood. In the past years, several studies identified different molecular mechanisms and cellular pathways as being impaired or deregulated in MJD. Autophagy, proteolysis or post-translational modifications, among other processes, were implicated in MJD pathogenesis. From these studies it was possible to identify new targets for therapeutic intervention, which in some cases proved successful in models of disease.
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17
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Wang Z. Experimental and Clinical Strategies for Treating Spinocerebellar Ataxia Type 3. Neuroscience 2017; 371:138-154. [PMID: 29229556 DOI: 10.1016/j.neuroscience.2017.11.051] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 11/28/2017] [Accepted: 11/30/2017] [Indexed: 01/02/2023]
Abstract
Spinocerebellar ataxia type 3 (SCA3), or Machado-Joseph disease (MJD), is an autosomal dominant neurodegenerative disorder caused by the expansion of a polyglutamine (polyQ) tract in the ataxin-3 protein. To date, there is no effective therapy available to prevent progression of this disease. However, clinical strategies for alleviating various symptoms are imperative to promote a better quality of life for SCA3/MJD patients. Furthermore, experimental therapeutic strategies, including gene silencing or mutant protein clearance, mutant polyQ protein modification, stabilizing the native protein conformation, rescue of cellular dysfunction and neuromodulation to slow the progression of SCA3/MJD, have been developed. In this study, based on the current knowledge, I detail the clinical and experimental therapeutic strategies for treating SCA3/MJD, paying particular attention to drug discovery.
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Affiliation(s)
- Zijian Wang
- Genetic Engineering Laboratory, College of Biological and Environmental Engineering, Xi'an University, Xi'an, Shaanxi 710065, China.
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18
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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: 17] [Impact Index Per Article: 2.4] [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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19
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Sambataro F, Pennuto M. Post-translational Modifications and Protein Quality Control in Motor Neuron and Polyglutamine Diseases. Front Mol Neurosci 2017; 10:82. [PMID: 28408866 PMCID: PMC5374214 DOI: 10.3389/fnmol.2017.00082] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2017] [Accepted: 03/08/2017] [Indexed: 11/30/2022] Open
Abstract
Neurodegenerative diseases, including motor neuron and polyglutamine (polyQ) diseases, are a broad class of neurological disorders. These diseases are characterized by neuronal dysfunction and death, and by the accumulation of toxic aggregation-prone proteins in the forms of inclusions and micro-aggregates. Protein quality control is a cellular mechanism to reduce the burden of accumulation of misfolded proteins, a function that results from the coordinated actions of chaperones and degradation systems, such as the ubiquitin-proteasome system (UPS) and autophagy-lysosomal degradation system. The rate of turnover, aggregation and degradation of the disease-causing proteins is modulated by post-translational modifications (PTMs), such as phosphorylation, arginine methylation, palmitoylation, acetylation, SUMOylation, ubiquitination, and proteolytic cleavage. Here, we describe how PTMs of proteins linked to motor neuron and polyQ diseases can either enhance or suppress protein quality control check and protein aggregation and degradation. The identification of molecular strategies targeting these modifications may offer novel avenues for the treatment of these yet incurable diseases.
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Affiliation(s)
- Fabio Sambataro
- Department of Experimental and Clinical Medical Sciences, University of UdineUdine, Italy
| | - Maria Pennuto
- Centre for Integrative Biology, Dulbecco Telethon Institute, University of TrentoTrento, Italy
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20
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Kuiper EFE, de Mattos EP, Jardim LB, Kampinga HH, Bergink S. Chaperones in Polyglutamine Aggregation: Beyond the Q-Stretch. Front Neurosci 2017; 11:145. [PMID: 28386214 PMCID: PMC5362620 DOI: 10.3389/fnins.2017.00145] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 03/08/2017] [Indexed: 01/12/2023] Open
Abstract
Expanded polyglutamine (polyQ) stretches in at least nine unrelated proteins lead to inherited neuronal dysfunction and degeneration. The expansion size in all diseases correlates with age at onset (AO) of disease and with polyQ protein aggregation, indicating that the expanded polyQ stretch is the main driving force for the disease onset. Interestingly, there is marked interpatient variability in expansion thresholds for a given disease. Between different polyQ diseases the repeat length vs. AO also indicates the existence of modulatory effects on aggregation of the upstream and downstream amino acid sequences flanking the Q expansion. This can be either due to intrinsic modulation of aggregation by the flanking regions, or due to differential interaction with other proteins, such as the components of the cellular protein quality control network. Indeed, several lines of evidence suggest that molecular chaperones have impact on the handling of different polyQ proteins. Here, we review factors differentially influencing polyQ aggregation: the Q-stretch itself, modulatory flanking sequences, interaction partners, cleavage of polyQ-containing proteins, and post-translational modifications, with a special focus on the role of molecular chaperones. By discussing typical examples of how these factors influence aggregation, we provide more insight on the variability of AO between different diseases as well as within the same polyQ disorder, on the molecular level.
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Affiliation(s)
- E F E Kuiper
- Department of Cell Biology, University Medical Center Groningen, University of Groningen Groningen, Netherlands
| | - Eduardo P de Mattos
- Department of Cell Biology, University Medical Center Groningen, University of GroningenGroningen, Netherlands; Programa de Pós-Graduação em Genética e Biologia Molecular, Department of Genetics, Universidade Federal do Rio Grande do SulPorto Alegre, Brazil; Medical Genetics Service, Hospital de Clínicas de Porto AlegrePorto Alegre, Brazil
| | - Laura B Jardim
- Programa de Pós-Graduação em Genética e Biologia Molecular, Department of Genetics, Universidade Federal do Rio Grande do SulPorto Alegre, Brazil; Medical Genetics Service, Hospital de Clínicas de Porto AlegrePorto Alegre, Brazil; Departamento de Medicina Interna, Universidade Federal do Rio Grande do SulPorto Alegre, Brazil
| | - Harm H Kampinga
- Department of Cell Biology, University Medical Center Groningen, University of Groningen Groningen, Netherlands
| | - Steven Bergink
- Department of Cell Biology, University Medical Center Groningen, University of Groningen Groningen, Netherlands
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21
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Weber JJ, Golla M, Guaitoli G, Wanichawan P, Hayer SN, Hauser S, Krahl AC, Nagel M, Samer S, Aronica E, Carlson CR, Schöls L, Riess O, Gloeckner CJ, Nguyen HP, Hübener-Schmid J. A combinatorial approach to identify calpain cleavage sites in the Machado-Joseph disease protein ataxin-3. Brain 2017; 140:1280-1299. [DOI: 10.1093/brain/awx039] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 01/06/2017] [Indexed: 11/13/2022] Open
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22
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Kristensen LV, Oppermann FS, Rauen MJ, Hartmann-Petersen R, Thirstrup K. Polyglutamine expansion of ataxin-3 alters its degree of ubiquitination and phosphorylation at specific sites. Neurochem Int 2017; 105:42-50. [PMID: 28065793 DOI: 10.1016/j.neuint.2016.12.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2016] [Revised: 11/18/2016] [Accepted: 12/20/2016] [Indexed: 02/02/2023]
Abstract
Ubiquitination and phosphorylation of proteins represent post translational modifications (PTMs) capable of regulating a variety of cellular processes. In the neurodegenerative disorder spinocerebellar ataxia type 3 (SCA3), the disease causing protein ataxin-3 carries an expanded polyglutamine (polyQ) stretch causing it to aggregate in nuclear inclusions. These inclusions are decorated with ubiquitin suggestive of a malfunction in the clearance of the mutant protein. Differences in ubiquitin chain topology between normal and polyQ expanded ataxin-3 could be involved in the differential clearance of the two proteins and play a role in SCA3 pathogenesis. Likewise, changes in phosphorylation patterns between the two variants could contribute to pathogenic processes involved in SCA3. We therefore determined the ubiquitination and phosphorylation patterns, together with the ubiquitin-linkage types associated with normal and polyQ expanded ataxin-3 by mass spectrometry (MS). This analysis revealed a similar ubiquitin linkage pattern on normal and expanded ataxin-3. However, the distribution of ubiquitinated lysine residues was altered in polyQ expanded ataxin-3, with increased ubiquitination at the new identified ubiquitination site lysine-8. MS analysis of phosphorylation also revealed novel phosphorylation sites in ataxin-3, and an increase in phosphorylation of expanded ataxin-3 at several positions. The study suggests that differences in clearance of normal and expanded ataxin-3 are not attributed to differences in ubiquitin-linkage pattern. However, the observed differences between the normal and polyQ expanded ataxin-3 with respect to the degree of ubiquitination and phosphorylation on specific sites may have an impact on ataxin-3 function and SCA3 pathogenesis.
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Affiliation(s)
- Line V Kristensen
- Department of Neurodegeneration, H. Lundbeck A/S, Ottiliavej 9, 2500 Valby, Denmark; Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen N, Denmark.
| | - Felix S Oppermann
- Evotec München GmbH, Am Klopferspitz 19a, 82152 Martinsried, Germany
| | - Matthias J Rauen
- Department of Neurodegeneration, H. Lundbeck A/S, Ottiliavej 9, 2500 Valby, Denmark; Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark
| | | | - Kenneth Thirstrup
- Department of Neurodegeneration, H. Lundbeck A/S, Ottiliavej 9, 2500 Valby, Denmark
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23
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Matos CA, Nóbrega C, Louros SR, Almeida B, Ferreiro E, Valero J, Pereira de Almeida L, Macedo-Ribeiro S, Carvalho AL. Ataxin-3 phosphorylation decreases neuronal defects in spinocerebellar ataxia type 3 models. J Cell Biol 2016; 212:465-80. [PMID: 26880203 PMCID: PMC4754714 DOI: 10.1083/jcb.201506025] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Ataxin-3, the protein involved in spinocerebellar ataxia type 3 or Machado-Joseph disease, causes dendritic and synapse loss in cultured neurons when expanded, and mutation of phosphorylation site S12 reduces aggregation, neuronal loss, and synapse loss. Different neurodegenerative diseases are caused by aberrant elongation of repeated glutamine sequences normally found in particular human proteins. Although the proteins involved are ubiquitously distributed in human tissues, toxicity targets only defined neuronal populations. Changes caused by an expanded polyglutamine protein are possibly influenced by endogenous cellular mechanisms, which may be harnessed to produce neuroprotection. Here, we show that ataxin-3, the protein involved in spinocerebellar ataxia type 3, also known as Machado-Joseph disease, causes dendritic and synapse loss in cultured neurons when expanded. We report that S12 of ataxin-3 is phosphorylated in neurons and that mutating this residue so as to mimic a constitutive phosphorylated state counters the neuromorphologic defects observed. In rats stereotaxically injected with expanded ataxin-3–encoding lentiviral vectors, mutation of serine 12 reduces aggregation, neuronal loss, and synapse loss. Our results suggest that S12 plays a role in the pathogenic pathways mediated by polyglutamine-expanded ataxin-3 and that phosphorylation of this residue protects against toxicity.
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Affiliation(s)
- Carlos A Matos
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra, 3004-517 Coimbra, Portugal
| | - Clévio Nóbrega
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Susana R Louros
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Bruno Almeida
- Instituto de Biologia Molecular e Celular and Instituto de Investigação e Inovação em Saúde, University of Porto, 4200-135 Porto, Portugal
| | - Elisabete Ferreiro
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal Institute for Interdisciplinary Research, University of Coimbra, 3030-789 Coimbra, Portugal
| | - Jorge Valero
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal Ikerbasque Basque Foundation for Science and Achucarro Basque Center for Neuroscience, Bizkaia Science and Technology Park, E-48170 Zamudio, Spain
| | - Luís Pereira de Almeida
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal Faculty of Pharmacy, University of Coimbra, 3000-548 Coimbra, Portugal
| | - Sandra Macedo-Ribeiro
- Instituto de Biologia Molecular e Celular and Instituto de Investigação e Inovação em Saúde, University of Porto, 4200-135 Porto, Portugal
| | - Ana Luísa Carvalho
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra, 3004-517 Coimbra, Portugal
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24
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Evers MM, Toonen LJA, van Roon-Mom WMC. Ataxin-3 protein and RNA toxicity in spinocerebellar ataxia type 3: current insights and emerging therapeutic strategies. Mol Neurobiol 2014; 49:1513-31. [PMID: 24293103 PMCID: PMC4012159 DOI: 10.1007/s12035-013-8596-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 11/14/2013] [Indexed: 01/10/2023]
Abstract
Ataxin-3 is a ubiquitously expressed deubiqutinating enzyme with important functions in the proteasomal protein degradation pathway and regulation of transcription. The C-terminus of the ataxin-3 protein contains a polyglutamine (PolyQ) region that, when mutationally expanded to over 52 glutamines, causes the neurodegenerative disease spinocerebellar ataxia 3 (SCA3). In spite of extensive research, the molecular mechanisms underlying the cellular toxicity resulting from mutant ataxin-3 remain elusive and no preventive treatment is currently available. It has become clear over the last decade that the hallmark intracellular ataxin-3 aggregates are likely not the main toxic entity in SCA3. Instead, the soluble PolyQ containing fragments arising from proteolytic cleavage of ataxin-3 by caspases and calpains are now regarded to be of greater influence in pathogenesis. In addition, recent evidence suggests potential involvement of a RNA toxicity component in SCA3 and other PolyQ expansion disorders, increasing the pathogenic complexity. Herein, we review the functioning of ataxin-3 and the involvement of known protein and RNA toxicity mechanisms of mutant ataxin-3 that have been discovered, as well as future opportunities for therapeutic intervention.
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Affiliation(s)
- Melvin M. Evers
- Department of Human Genetics, Leiden University Medical Center, Albinusdreef 2, 2333ZA Leiden, The Netherlands
| | - Lodewijk J. A. Toonen
- Department of Human Genetics, Leiden University Medical Center, Albinusdreef 2, 2333ZA Leiden, The Netherlands
| | - Willeke M. C. van Roon-Mom
- Department of Human Genetics, Leiden University Medical Center, Albinusdreef 2, 2333ZA Leiden, The Netherlands
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25
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Guan WJ, Xia KD, Ma YT, Liu YT, Shi YT, Jiang H, Shen L, Xia K, Li JD, Tang BS, Wang JL. Transglutaminase 6 interacts with polyQ proteins and promotes the formation of polyQ aggregates. Biochem Biophys Res Commun 2013; 437:94-100. [DOI: 10.1016/j.bbrc.2013.06.044] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Accepted: 06/13/2013] [Indexed: 01/07/2023]
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26
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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: 37] [Impact Index Per Article: 3.4] [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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27
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Jadhav S, Zilka N, Novak M. Protein truncation as a common denominator of human neurodegenerative foldopathies. Mol Neurobiol 2013; 48:516-32. [PMID: 23516100 DOI: 10.1007/s12035-013-8440-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Accepted: 03/05/2013] [Indexed: 12/13/2022]
Abstract
Neurodegenerative foldopathies are characterized by aberrant folding of diseased modified proteins, which are major constituents of the intracellular and extracellular lesions. These lesions correlate with the cognitive and/or motor impairment seen in these diseases. The majority of the disease modified proteins in neurodegenerative foldopathies belongs to the group of proteins termed as intrinsically disordered proteins (IDPs). Several independent studies have showed that abnormal protein processing constitutes the key pathological feature of these disorders. The current review focuses on protein truncation as a common denominator of neurodegenerative foldopathies, which is considered to be the major driving force behind the pathological metamorphosis of brain IDPs. The aim of the review is to emphasize the key role of the protein truncation in the pathogenic pathways of neurodegenerative diseases. A deeper understanding of the complex downstream processing of the IDPs, resulting in the generation of pathologically modified proteins might be a prerequisite for the successful therapeutic strategies of several fatal neurodegenerative diseases.
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Affiliation(s)
- Santosh Jadhav
- Institute of Neuroimmunology, Slovak Academy of Sciences, Centre of Excellence for Alzheimer's Disease and Related Disorders, Dubravska cesta 9, 845 10, Bratislava, Slovak Republic
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28
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Magaña JJ, Velázquez-Pérez L, Cisneros B. Spinocerebellar ataxia type 2: clinical presentation, molecular mechanisms, and therapeutic perspectives. Mol Neurobiol 2012; 47:90-104. [PMID: 22996397 DOI: 10.1007/s12035-012-8348-8] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Accepted: 09/05/2012] [Indexed: 12/13/2022]
Abstract
Spinocerebellar ataxia type 2 (SCA2) is an autosomal dominant genetic disease characterized by cerebellar dysfunction associated with slow saccades, early hyporeflexia, severe tremor of postural or action type, peripheral neuropathy, cognitive disorders, and other multisystemic features. SCA2, one of the most common ataxias worldwide, is caused by the expansion of a CAG triplet repeat located in the N-terminal coding region of the ATXN2 gene, which results in the incorporation of a segment of polyglutamines in the mutant protein, being longer expansions associated with earlier onset and more sever disease in subsequent generations. In this review, we offer a detailed description of the clinical manifestations of SCA2 and compile the experimental evidence showing the participation of ataxin-2 in crucial cellular processes, including messenger RNA maturation and translation, and endocytosis. In addition, we discuss in the light of present data the potential molecular mechanisms underlying SCA2 pathogenesis. The mutant protein exhibits a toxic gain of function that is mainly attributed to the generation of neuronal inclusions of phosphorylated and/or proteolytic cleaved mutant ataxin-2, which might alter normal ataxin-2 function, leading to cell dysfunction and death of target cells. In the final part of this review, we discuss the perspectives of development of therapeutic strategies for SCA2. Based on previous experience with other polyglutamine disorders and considering the molecular basis of SCA2 pathogenesis, a nuclei-acid-based strategy focused on the specific silencing of the dominant disease allele that preserves the expression of the wild-type allele is highly desirable and might prevent toxic neurodegenerative sequelae.
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Affiliation(s)
- J J Magaña
- Department of Genetics, National Rehabilitation Institute (INR), Mexico City, Mexico
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Laço MN, Cortes L, Travis SM, Paulson HL, Rego AC. Valosin-containing protein (VCP/p97) is an activator of wild-type ataxin-3. PLoS One 2012; 7:e43563. [PMID: 22970133 PMCID: PMC3435318 DOI: 10.1371/journal.pone.0043563] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Accepted: 07/26/2012] [Indexed: 01/11/2023] Open
Abstract
Alterations in the ubiquitin-proteasome system (UPS) have been reported in several neurodegenerative disorders characterized by protein misfolding and aggregation, including the polylgutamine diseases. Machado-Joseph disease (MJD) or Spinocerebellar Ataxia type 3 is caused by a polyglutamine-encoding CAG expansion in the ATXN3 gene, which encodes a 42 kDa deubiquitinating enzyme (DUB), ataxin-3. We investigated ataxin-3 deubiquitinating activity and the functional relevance of ataxin-3 interactions with two proteins previously described to interact with ataxin-3, hHR23A and valosin-containing protein (VCP/p97). We confirmed ataxin-3 affinity for both hHR23A and VCP/p97. hHR23A and ataxin-3 were shown to co-localize in discrete nuclear foci, while VCP/p97 was primarily cytoplasmic. hHR23A and VCP/p97 recombinant proteins were added, separately or together, to normal and expanded ataxin-3 in in vitro deubiquitination assays to evaluate their influence on ataxin-3 activity. VCP/p97 was shown to be an activator specifically of wild-type ataxin-3, exhibiting no effect on expanded ataxin-3, In contrast, we observed no significant alterations in ataxin-3 enzyme kinetics or substrate preference in the presence of hHR23A alone or in combination with VCP. Based on our results we propose a model where ataxin-3 normally functions with its interactors to specify the cellular fate of ubiquitinated proteins.
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Affiliation(s)
- Mário N. Laço
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Luisa Cortes
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Sue M. Travis
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Henry L. Paulson
- Department of Neurology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
- * E-mail: (HLP); (ACR)
| | - A. Cristina Rego
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- * E-mail: (HLP); (ACR)
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Costa MDC, Paulson HL. Toward understanding Machado-Joseph disease. Prog Neurobiol 2011; 97:239-57. [PMID: 22133674 DOI: 10.1016/j.pneurobio.2011.11.006] [Citation(s) in RCA: 209] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2011] [Revised: 11/10/2011] [Accepted: 11/14/2011] [Indexed: 12/16/2022]
Abstract
Machado-Joseph disease (MJD), also known as spinocerebellar ataxia type 3 (SCA3), is the most common inherited spinocerebellar ataxia and one of many polyglutamine neurodegenerative diseases. In MJD, a CAG repeat expansion encodes an abnormally long polyglutamine (polyQ) tract in the disease protein, ATXN3. Here we review MJD, focusing primarily on the function and dysfunction of ATXN3 and on advances toward potential therapies. ATXN3 is a deubiquitinating enzyme (DUB) whose highly specialized properties suggest that it participates in ubiquitin-dependent proteostasis. By virtue of its interactions with VCP, various ubiquitin ligases and other ubiquitin-linked proteins, ATXN3 may help regulate the stability or activity of many proteins in diverse cellular pathways implicated in proteotoxic stress response, aging, and cell differentiation. Expansion of the polyQ tract in ATXN3 is thought to promote an altered conformation in the protein, leading to changes in interactions with native partners and to the formation of insoluble aggregates. The development of a wide range of cellular and animal models of MJD has been crucial to the emerging understanding of ATXN3 dysfunction upon polyQ expansion. Despite many advances, however, the principal molecular mechanisms by which mutant ATXN3 elicits neurotoxicity remain elusive. In a chronic degenerative disease like MJD, it is conceivable that mutant ATXN3 triggers multiple, interconnected pathogenic cascades that precipitate cellular dysfunction and eventual cell death. A better understanding of these complex molecular mechanisms will be important as scientists and clinicians begin to focus on developing effective therapies for this incurable, fatal disorder.
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Affiliation(s)
- Maria do Carmo Costa
- Department of Neurology, University of Michigan, A. Alfred Taubman Biomedical Sciences Research Building-BSRB, 109 Zina Pitcher Place, Ann Arbor, MI 48109-2200, USA.
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Matos CA, de Macedo-Ribeiro S, Carvalho AL. Polyglutamine diseases: The special case of ataxin-3 and Machado–Joseph disease. Prog Neurobiol 2011; 95:26-48. [DOI: 10.1016/j.pneurobio.2011.06.007] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Revised: 06/06/2011] [Accepted: 06/07/2011] [Indexed: 10/18/2022]
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Gao XC, Zhou CJ, Zhou ZR, Zhang YH, Zheng XM, Song AX, Hu HY. Co-chaperone HSJ1a dually regulates the proteasomal degradation of ataxin-3. PLoS One 2011; 6:e19763. [PMID: 21625540 PMCID: PMC3098244 DOI: 10.1371/journal.pone.0019763] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Accepted: 04/06/2011] [Indexed: 11/22/2022] Open
Abstract
Homo sapiens J domain protein (HSJ1) is a J-domain containing co-chaperone that is known to stimulate ATPase activity of HSP70 chaperone, while it also harbors two ubiquitin (Ub)-interacting motifs (UIMs) that may bind with ubiquitinated substrates and potentially function in protein degradation. We studied the effects of HSJ1a on the protein levels of both normal and the disease–related polyQ-expanded forms of ataxin-3 (Atx3) in cells. The results demonstrate that the N-terminal J-domain and the C-terminal UIM domain of HSJ1a exert opposite functions in regulating the protein level of cellular overexpressed Atx3. This dual regulation is dependent on the binding of the J-domain with HSP70, and the UIM domain with polyUb chains. The J-domain down-regulates the protein level of Atx3 through HSP70 mediated proteasomal degradation, while the UIM domain may alleviate this process via maintaining the ubiquitinated Atx3. We propose that co-chaperone HSJ1a orchestrates the balance of substrates in stressed cells in a Yin-Yang manner.
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Affiliation(s)
- Xue-Chao Gao
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Chen-Jie Zhou
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Zi-Ren Zhou
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Yu-Hang Zhang
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Xue-Ming Zheng
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Ai-Xin Song
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Hong-Yu Hu
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
- * E-mail:
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Hands SL, Wyttenbach A. Neurotoxic protein oligomerisation associated with polyglutamine diseases. Acta Neuropathol 2010; 120:419-37. [PMID: 20514488 DOI: 10.1007/s00401-010-0703-0] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2010] [Revised: 05/20/2010] [Accepted: 05/23/2010] [Indexed: 02/07/2023]
Abstract
Polyglutamine (polyQ) diseases are associated with a CAG/polyQ expansion mutation in unrelated proteins. Upon elongation of the glutamine tract, disease proteins aggregate within cells, mainly in the central nervous system (CNS) and this aggregation process is associated with neurotoxicity. However, it remains unclear to what extent and how this aggregation causes neuronal dysfunction in the CNS. Aiming at preventing neuronal dysfunction, it will be crucial to determine the links between aggregation and cellular dysfunction, understand the folding pathway of polyQ proteins and discover the relative neurotoxicity of polyQ protein species formed along the aggregation pathway. Here, we review what is known about conformations of polyQ peptides and proteins in their monomeric state from experimental and modelling data, how conformational changes of polyQ proteins relate to their oligomerisation and morphology of aggregates and which cellular function are impaired by oligomers, in vitro and in vivo. We also summarise the key modulatory cellular mechanisms and co-factors, which could affect the folding pathway and kinetics of polyQ aggregation. Although many studies have investigated the relationship between polyQ aggregation and toxicity, these have mainly focussed on investigating changes in the formation of the classical hallmark of polyQ diseases, i.e. microscopically visible inclusion bodies. However, recent studies in which oligomeric species have been considered start to shed light on the identity of neurotoxic oligomeric species. Initial evidence suggests that conformational changes induced by polyQ expansions and their surrounding sequence lead to the formation of particular oligomeric intermediates that may differentially affect neurotoxicity.
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Affiliation(s)
- Sarah L Hands
- Southampton Neuroscience Group, School of Biological Sciences, University of Southampton, Southampton SO16 7PX, UK
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Fighting disease by selective autophagy of aggregate-prone proteins. FEBS Lett 2010; 584:2635-45. [DOI: 10.1016/j.febslet.2010.04.041] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2010] [Revised: 04/09/2010] [Accepted: 04/15/2010] [Indexed: 12/12/2022]
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Wang Y, Lin F, Qin ZH. The role of post-translational modifications of huntingtin in the pathogenesis of Huntington's disease. Neurosci Bull 2010; 26:153-62. [PMID: 20332821 PMCID: PMC5560368 DOI: 10.1007/s12264-010-1118-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Accepted: 12/08/2009] [Indexed: 10/19/2022] Open
Abstract
Post-translational modifications are rapid, effective and reversible ways to regulate protein stability, localization, function, and their interactions with other molecules. Post-translational modifications usually occur as chemical modifications at amino acid residues, including SUMOylation, phosphorylation, palmitoylation, acetylation, etc. These complex biochemical modifications tightly regulate and control a variety of cellular processes. Several forms of post-translational modifications of huntingtin (Htt) have been described. These modifications affect Htt metabolism, protein-protein interactions and cellular toxicity. Cleavage and clearance of mutant Htt, and the interactions between mutant Htt and other cellular proteins are important biochemical events leading to Huntington's disease. Therefore, identifying signaling pathways of Htt modification and evaluating the significance of Htt modifications would lead to a better understanding of the normal function of wild-type Htt and the pathogenic mechanisms of mutant Htt.
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Affiliation(s)
- Yan Wang
- Department of Pharmacology, Laboratory of Aging and Nervous Diseases (SZS0703), Soochow University School of Medicine, Suzhou, 215123 China
| | - Fang Lin
- Department of Pharmacology, Laboratory of Aging and Nervous Diseases (SZS0703), Soochow University School of Medicine, Suzhou, 215123 China
| | - Zheng-Hong Qin
- Department of Pharmacology, Laboratory of Aging and Nervous Diseases (SZS0703), Soochow University School of Medicine, Suzhou, 215123 China
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La Spada AR, Taylor JP. Repeat expansion disease: progress and puzzles in disease pathogenesis. Nat Rev Genet 2010; 11:247-58. [PMID: 20177426 PMCID: PMC4704680 DOI: 10.1038/nrg2748] [Citation(s) in RCA: 336] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Repeat expansion mutations cause at least 22 inherited neurological diseases. The complexity of repeat disease genetics and pathobiology has revealed unexpected shared themes and mechanistic pathways among the diseases, such as RNA toxicity. Also, investigation of the polyglutamine diseases has identified post-translational modification as a key step in the pathogenic cascade and has shown that the autophagy pathway has an important role in the degradation of misfolded proteins--two themes that are likely to be relevant to the entire neurodegeneration field. Insights from repeat disease research are catalysing new lines of study that should not only elucidate molecular mechanisms of disease but also highlight opportunities for therapeutic intervention for these currently untreatable disorders.
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Affiliation(s)
- Albert R La Spada
- Division of Genetics, Department of Pediatrics, Institute for Genomic Medicine, University of California-San Diego, La Jolla, California 92093, USA.
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Pastori V, Sangalli E, Coccetti P, Pozzi C, Nonnis S, Tedeschi G, Fusi P. CK2 and GSK3 phosphorylation on S29 controls wild-type ATXN3 nuclear uptake. Biochim Biophys Acta Mol Basis Dis 2010; 1802:583-92. [PMID: 20347968 DOI: 10.1016/j.bbadis.2010.03.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2009] [Revised: 03/09/2010] [Accepted: 03/14/2010] [Indexed: 10/19/2022]
Abstract
In the present work we show that murine ATXN3 (ATXN3Q6) nuclear uptake is promoted by phosphorylation on serine 29, a highly conserved residue inside the Josephin domain. Both casein kinase 2 (CK2) and glycogen synthase kinase 3 (GSK3) are able to carry out phosphorylation on this residue. S29 phosphorylation was initially assessed in vitro on purified ATXN3Q6, and subsequently confirmed in transfected COS-7 cells, by MS analysis. Site-directed mutagenesis of S29 to an alanine was shown to strongly reduce nuclear uptake, in COS-7 transiently transfected cells overexpressing ATXN3Q6, while substitution with phospho-mimic aspartic acid restored the wild-type phenotype. Finally, treatment with CK2 and GSK3 inhibitors prevented S29 phosphorylation and strongly inhibited nuclear uptake, showing that both kinases are involved in ATXN3Q6 subcellular sorting. Although other authors have previously addressed this issue, we show for the first time that ATXN3 is phosphorylated inside the Josephin domain and that S29 phosphorylation is involved in nuclear uptake of ATXN3.
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Affiliation(s)
- V Pastori
- Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, 20126 Milan, Italy
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Bauer PO, Nukina N. The pathogenic mechanisms of polyglutamine diseases and current therapeutic strategies. J Neurochem 2009; 110:1737-65. [PMID: 19650870 DOI: 10.1111/j.1471-4159.2009.06302.x] [Citation(s) in RCA: 144] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Expansion of CAG trinucleotide repeat within the coding region of several genes results in the production of proteins with expanded polyglutamine (PolyQ) stretch. The expression of these pathogenic proteins leads to PolyQ diseases, such as Huntington's disease or several types of spinocerebellar ataxias. This family of neurodegenerative disorders is characterized by constant progression of the symptoms and molecularly, by the accumulation of mutant proteins inside neurons causing their dysfunction and eventually death. So far, no effective therapy actually preventing the physical and/or mental decline has been developed. Experimental therapeutic strategies either target the levels or processing of mutant proteins in an attempt to prevent cellular deterioration, or they are aimed at the downstream pathologic effects to reverse or ameliorate the caused damages. Certain pathomechanistic aspects of PolyQ disorders are discussed here. Relevance of disease models and recent knowledge of therapeutic possibilities is reviewed and updated.
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Affiliation(s)
- Peter O Bauer
- Laboratory for Structural Neuropathology, RIKEN Brain Science Institute, Saitama, Japan
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Mueller T, Breuer P, Schmitt I, Walter J, Evert BO, Wüllner U. CK2-dependent phosphorylation determines cellular localization and stability of ataxin-3. Hum Mol Genet 2009; 18:3334-43. [PMID: 19542537 DOI: 10.1093/hmg/ddp274] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The nuclear presence of the expanded disease proteins is of critical importance for the pathogeneses of polyglutamine diseases. Here we show that protein casein kinase 2 (CK2)-dependent phosphorylation controls the nuclear localization, aggregation and stability of ataxin-3 (ATXN3), the disease protein in spinocerebellar ataxia type 3 (SCA3). Serine 340 and 352 within the third ubiquitin-interacting motif of ATXN3 were particularly important for nuclear localization of normal and expanded ATXN3 and mutation of these sites robustly reduced the formation of nuclear inclusions; a putative nuclear leader sequence was not required. ATXN3 associated with CK2alpha and pharmacological inhibition of CK2 decreased nuclear ATXN3 levels and the formation of nuclear inclusions. Moreover, we found that ATXN3 shifted to the nucleus upon thermal stress in a CK2-dependent manner, indicating a key role of CK2-mediated phosphorylation of ATXN3 in SCA3 pathophysiology.
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Affiliation(s)
- Thorsten Mueller
- Department of Neurology, Friedrich-Wilhelms-University Bonn, UKB, 53105 Bonn, Germany
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Pennuto M, Palazzolo I, Poletti A. Post-translational modifications of expanded polyglutamine proteins: impact on neurotoxicity. Hum Mol Genet 2009; 18:R40-7. [PMID: 19297400 DOI: 10.1093/hmg/ddn412] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Polyglutamine diseases are a family of nine neurodegenerative disorders caused by expansion in different genes of a CAG triplet repeat stretch, which encodes an elongated polyglutamine tract. This polyglutamine tract is thought to confer a toxic gain of function to the bearing proteins, which leads to late onset and progressive loss of neurons in specific regions of the central nervous system. The mechanisms underlying specificity for neuronal vulnerability remain enigmatic. One explanation is that the polyglutamine tract is not the only determinant of neurodegeneration and that protein context and post-translational events may also be crucial for pathogenesis. Here, we review how post-translational modifications of the polyglutamine proteins contribute to modulate neurotoxicity.
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Affiliation(s)
- Maria Pennuto
- Department of Neurology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA.
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Tao RS, Fei EK, Ying Z, Wang HF, Wang GH. Casein kinase 2 interacts with and phosphorylates ataxin-3. Neurosci Bull 2009; 24:271-7. [PMID: 18839019 DOI: 10.1007/s12264-008-0605-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
OBJECTIVE Machado-Joseph disease (MJD)/Spinocerebellar ataxia type 3 (SCA3) is an autosomal dominant neurodegenerative disorder caused by an expansion of polyglutamine tract near the C-terminus of the MJD1 gene product, ataxin-3. The precise mechanism of the MJD/SCA3 pathogenesis remains unclear. A growing body of evidence demonstrates that phosphorylation plays an important role in the pathogenesis of many neurodegenerative diseases. However, few kinases are known to phosphorylate ataxin-3. The present study is to explore whether ataxin-3 is a substrate of casein kinase 2 (CK2). METHODS The interaction between ataxin-3 and CK2 was identified by glutathione S-transferase (GST) pull-down assay and co-immunoprecipition assay. The phosphorylation of ataxin-3 by CK2 was measured by in vitro phosphorylation assays. Results (1) Both wild type and expanded ataxin-3 interacted with CK2alpha and CK2beta in vitro. (2) In 293 cells, both wild type and expanded ataxin-3 interacted with CK2beta, but not CK2alpha. (3) CK2 phosphorylated wild type and expanded ataxin-3. CONCLUSION Ataxin-3 is a substrate of protein kinase CK2.
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Affiliation(s)
- Rui-Song Tao
- Laboratory of Molecular Neuropathology, Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
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Jia NL, Fei EK, Ying Z, Wang HF, Wang GH. PolyQ-expanded ataxin-3 interacts with full-length ataxin-3 in a polyQ length-dependent manner. Neurosci Bull 2008; 24:201-8. [PMID: 18668148 DOI: 10.1007/s12264-008-0326-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
OBJECTIVE Machado-Joseph disease (MJD), also known as spinocerebellar ataxia type 3 (SCA3), is a dominant neurodegenerative disorder caused by an expansion of the polyglutamine (polyQ) tract in MJD-1 gene product, ataxin-3 (AT3). This disease is characterized by the formation of intraneuronal inclusions, but the mechanism underlying their formation is still poorly understood. The present study is to explore the relationship between wild type (WT) AT3 and polyQ expanded AT3. METHODS Mouse neuroblastoma (N2a) cells or HEK293 cells were co-transfected with WT AT3 and different truncated forms of expanded AT3. The expressions of WT AT3 and the truncated forms of expanded AT3 were detected by Western blotting, and observed by an inverted fluorescent microscope. The interactions between AT3 and different truncated forms of expanded AT3 were detected by immunoprecipitation and GST pull-down assays. RESULTS Using fluorescent microscope, we observed that the truncated forms of expanded AT3 aggregate in transfected cells, and the full-length WT AT3 is recruited onto the aggregates. However, no aggregates were observed in cells transfected with the truncated forms of WT AT3. Immunoprecipitation and GST pull-down analyses indicate that WT AT3 interacts with the truncated AT3 in a polyQ length-dependent manner. CONCLUSION WT AT3 deposits in the aggregation that was formed by polyQ expanded AT3, which suggests that the formation of AT3 aggregation may affect the normal function of WT AT3 and increase polyQ protein toxicity in MJD.
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Affiliation(s)
- Na-Li Jia
- Laboratory of Molecular Neuropathology, Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, China
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Sarkar S, Rubinsztein DC. Huntington's disease: degradation of mutant huntingtin by autophagy. FEBS J 2008; 275:4263-70. [PMID: 18637946 DOI: 10.1111/j.1742-4658.2008.06562.x] [Citation(s) in RCA: 159] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Autophagy is a nonspecific bulk degradation pathway for long-lived cytoplasmic proteins, protein complexes, or damaged organelles. This process is also a major degradation pathway for many aggregate-prone, disease-causing proteins associated with neurodegenerative disorders, such as mutant huntingtin in Huntington's disease. In this review, we discuss factors regulating the degradation of mutant huntingtin by autophagy. We also report the growing list of new drugs/pathways that upregulate autophagy to enhance the clearance of this mutant protein, as autophagy upregulation may be a tractable strategy for the treatment of Huntington's disease.
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Affiliation(s)
- Sovan Sarkar
- Department of Medical Genetics, University of Cambridge, Cambridge Institute for Medical Research, Addenbrooke's Hospital, UK.
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