1
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Zhang Z, Gehin C, Abriata LA, Dal Peraro M, Lashuel H. Differential Effects of Post-translational Modifications on the Membrane Interaction of Huntingtin Protein. ACS Chem Neurosci 2024; 15:2408-2419. [PMID: 38752226 PMCID: PMC11191595 DOI: 10.1021/acschemneuro.4c00091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 04/05/2024] [Accepted: 05/06/2024] [Indexed: 05/25/2024] Open
Abstract
Huntington's disease is a neurodegenerative disorder caused by an expanded polyglutamine stretch near the N-terminus of the huntingtin (HTT) protein, rendering the protein more prone to aggregate. The first 17 residues in HTT (Nt17) interact with lipid membranes and harbor multiple post-translational modifications (PTMs) that can modulate HTT conformation and aggregation. In this study, we used a combination of biophysical studies and molecular simulations to investigate the effect of PTMs on the helicity of Nt17 in the presence of various lipid membranes. We demonstrate that anionic lipids such as PI4P, PI(4,5)P2, and GM1 significantly enhance the helical structure of unmodified Nt17. This effect is attenuated by single acetylation events at K6, K9, or K15, whereas tri-acetylation at these sites abolishes Nt17-membrane interaction. Similarly, single phosphorylation at S13 and S16 decreased but did not abolish the POPG and PIP2-induced helicity, while dual phosphorylation at these sites markedly diminished Nt17 helicity, regardless of lipid composition. The helicity of Nt17 with phosphorylation at T3 is insensitive to the membrane environment. Oxidation at M8 variably affects membrane-induced helicity, highlighting a lipid-dependent modulation of the Nt17 structure. Altogether, our findings reveal differential effects of PTMs and crosstalks between PTMs on membrane interaction and conformation of HTT. Intriguingly, the effects of phosphorylation at T3 or single acetylation at K6, K9, and K15 on Nt17 conformation in the presence of certain membranes do not mirror that observed in the absence of membranes. Our studies provide novel insights into the complex relationship between Nt17 structure, PTMs, and membrane binding.
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Affiliation(s)
- Zhidian Zhang
- Laboratory
of Molecular and Chemical Biology of Neurodegeneration, School of
Life Sciences, Institute of Bioengineering,
Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne 1015, Switzerland
- Laboratory
for Biomolecular Modeling, School of Life Sciences, Institute of Bioengineering, Ecole Polytechnique Fédérale
de Lausanne (EPFL), Lausanne 1015, Switzerland
| | - Charlotte Gehin
- Laboratory
of Molecular and Chemical Biology of Neurodegeneration, School of
Life Sciences, Institute of Bioengineering,
Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne 1015, Switzerland
| | - Luciano A Abriata
- Laboratory
for Biomolecular Modeling, School of Life Sciences, Institute of Bioengineering, Ecole Polytechnique Fédérale
de Lausanne (EPFL), Lausanne 1015, Switzerland
| | - Matteo Dal Peraro
- Laboratory
for Biomolecular Modeling, School of Life Sciences, Institute of Bioengineering, Ecole Polytechnique Fédérale
de Lausanne (EPFL), Lausanne 1015, Switzerland
| | - Hilal Lashuel
- Laboratory
of Molecular and Chemical Biology of Neurodegeneration, School of
Life Sciences, Institute of Bioengineering,
Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne 1015, Switzerland
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2
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Mishra R, Gerlach GJ, Sahoo B, Camacho CJ, Wetzel R. A Targetable Self-association Surface of the Huntingtin exon1 Helical Tetramer Required for Assembly of Amyloid Pre-nucleation Oligomers. J Mol Biol 2024; 436:168607. [PMID: 38734203 DOI: 10.1016/j.jmb.2024.168607] [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: 12/13/2023] [Revised: 05/03/2024] [Accepted: 05/06/2024] [Indexed: 05/13/2024]
Abstract
Polyglutamine (polyQ) sequences undergo repeat-length dependent formation of disease-associated, amyloid-like cross-β core structures with kinetics and aggregate morphologies often influenced by the flanking sequences. In Huntington's disease (HD), the httNT segment on the polyQ's N-terminal flank enhances aggregation rates by changing amyloid nucleation from a classical homogeneous mechanism to a two-step process requiring an ɑ-helix-rich oligomeric intermediate. A folded, helix-rich httNT tetrameric structure suggested to be this critical intermediate was recently reported. Here we employ single alanine replacements along the httNT sequence to assess this proposed structure and refine the mechanistic model. We find that Ala replacement of hydrophobic residues within simple httNT peptides greatly suppresses helicity, supporting the tetramer model. These same helix-disruptive replacements in the httNT segment of an exon-1 analog greatly reduce aggregation kinetics, suggesting that an ɑ-helix rich multimer - either the tetramer or a larger multimer - plays an on-pathway role in nucleation. Surprisingly, several other Ala replacements actually enhance helicity and/or amyloid aggregation. The spatial localization of these residues on the tetramer surface suggests a self-association interface responsible for formation of the octomers and higher-order multimers most likely required for polyQ amyloid nucleation. Multimer docking of the tetramer, using the protein-protein docking algorithm ClusPro, predicts this symmetric surface to be a viable tetramer dimerization interface. Intriguingly, octomer formation brings the emerging polyQ chains into closer proximity at this tetramer-tetramer interface. Further supporting the potential importance of tetramer super-assembly, computational docking with a known exon-1 aggregation inhibitor predicts ligand contacts with residues at this interface.
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Affiliation(s)
- Rakesh Mishra
- Department Structural Biology, University of Pittsburgh School of Medicine Pittsburgh, PA 15260, USA.
| | - Gabriella J Gerlach
- Department of Computational and Systems Biology, University of Pittsburgh School of Medicine Pittsburgh, PA 15260, USA
| | - Bankanidhi Sahoo
- Department Structural Biology, University of Pittsburgh School of Medicine Pittsburgh, PA 15260, USA.
| | - Carlos J Camacho
- Department of Computational and Systems Biology, University of Pittsburgh School of Medicine Pittsburgh, PA 15260, USA.
| | - Ronald Wetzel
- Department Structural Biology, University of Pittsburgh School of Medicine Pittsburgh, PA 15260, USA.
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3
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Lu X, Lu J, Li S, Feng S, Wang Y, Cui L. The Role of Liquid-Liquid Phase Separation in the Accumulation of Pathological Proteins: New Perspectives on the Mechanism of Neurodegenerative Diseases. Aging Dis 2024:AD.2024.0209. [PMID: 38739933 DOI: 10.14336/ad.2024.0209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Accepted: 04/20/2024] [Indexed: 05/16/2024] Open
Abstract
It is widely accepted that living organisms form highly dynamic membrane-less organelles (MLOS) with various functions through phase separation, and the indispensable role that phase separation plays in the mechanisms of normal physiological functions and pathogenesis is gradually becoming clearer. Pathological aggregates, regarded as hallmarks of neurodegenerative diseases, have been revealed to be closely related to aberrant phase separation. Specific proteins are assembled into condensates and transform into insoluble inclusions through aberrant phase separation, contributing to the development of diseases. In this review, we present an overview of the progress of phase separation research, involving its biological mechanisms and the status of research in neurodegenerative diseases, focusing on five main disease-specific proteins, tau, TDP-43, FUS, α-Syn and HTT, and how exactly these proteins reside within dynamic liquid-like compartments and thus turn into solid deposits. Further studies will yield new perspectives for understanding the aggregation mechanisms and potential therapeutic strategies, and future research directions are anticipated.
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Affiliation(s)
- Xingyu Lu
- Guangdong Key Laboratory of Age-Related Cardiac and Cerebral Diseases, Affiliated Hospital of Guangdong Medical University, Zhanjiang, China
| | - Jiongtong Lu
- Guangdong Key Laboratory of Age-Related Cardiac and Cerebral Diseases, Affiliated Hospital of Guangdong Medical University, Zhanjiang, China
| | - Shengnan Li
- Guangdong Key Laboratory of Age-Related Cardiac and Cerebral Diseases, Affiliated Hospital of Guangdong Medical University, Zhanjiang, China
| | - Sifan Feng
- Guangdong Key Laboratory of Age-Related Cardiac and Cerebral Diseases, Affiliated Hospital of Guangdong Medical University, Zhanjiang, China
| | - Yan Wang
- Guangdong Key Laboratory of Age-Related Cardiac and Cerebral Diseases, Affiliated Hospital of Guangdong Medical University, Zhanjiang, China
| | - Lili Cui
- Guangdong Key Laboratory of Age-Related Cardiac and Cerebral Diseases, Affiliated Hospital of Guangdong Medical University, Zhanjiang, China
- The Marine Biomedical Research Institute of Guangdong, School of Ocean and Tropical Medicine, Guangdong Medical University, Zhanjiang, Guangdong, China
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4
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Islam MR, Jony MH, Thufa GK, Akash S, Dhar PS, Rahman MM, Afroz T, Ahmed M, Hemeg HA, Rauf A, Thiruvengadam M, Venkidasamy B. A clinical study and future prospects for bioactive compounds and semi-synthetic molecules in the therapies for Huntington's disease. Mol Neurobiol 2024; 61:1237-1270. [PMID: 37698833 DOI: 10.1007/s12035-023-03604-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 08/21/2023] [Indexed: 09/13/2023]
Abstract
A neurodegenerative disorder (ND) refers to Huntington's disease (HD) which affects memory loss, weight loss, and movement dysfunctions such as chorea and dystonia. In the striatum and brain, HD most typically impacts medium-spiny neurons. Molecular genetics, excitotoxicity, oxidative stress (OS), mitochondrial, and metabolic dysfunction are a few of the theories advanced to explicit the pathophysiology of neuronal damage and cell death. Numerous in-depth studies of the literature have supported the therapeutic advantages of natural products in HD experimental models and other treatment approaches. This article briefly discusses the neuroprotective impacts of natural compounds against HD models. The ability of the discovered natural compounds to suppress HD was tested using either in vitro or in vivo models. Many bioactive compounds considerably lessened the memory loss and motor coordination brought on by 3-nitropropionic acid (3-NP). Reduced lipid peroxidation, increased endogenous enzymatic antioxidants, reduced acetylcholinesterase activity, and enhanced mitochondrial energy generation have profoundly decreased the biochemical change. It is significant since histology showed that therapy with particular natural compounds lessened damage to the striatum caused by 3-NP. Moreover, natural products displayed varying degrees of neuroprotection in preclinical HD studies because of their antioxidant and anti-inflammatory properties, maintenance of mitochondrial function, activation of autophagy, and inhibition of apoptosis. This study highlighted about the importance of bioactive compounds and their semi-synthetic molecules in the treatment and prevention of HD.
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Affiliation(s)
- Md Rezaul Islam
- Department of Pharmacy, Faculty of Allied Health Sciences, Daffodil International University, 1207, Dhaka, Bangladesh
| | - Maruf Hossain Jony
- Department of Pharmacy, Faculty of Allied Health Sciences, Daffodil International University, 1207, Dhaka, Bangladesh
| | - Gazi Kaifeara Thufa
- Department of Pharmacy, Faculty of Allied Health Sciences, Daffodil International University, 1207, Dhaka, Bangladesh
| | - Shopnil Akash
- Department of Pharmacy, Faculty of Allied Health Sciences, Daffodil International University, 1207, Dhaka, Bangladesh
| | - Puja Sutra Dhar
- Department of Pharmacy, Faculty of Allied Health Sciences, Daffodil International University, 1207, Dhaka, Bangladesh
| | - Md Mominur Rahman
- Department of Pharmacy, Faculty of Allied Health Sciences, Daffodil International University, 1207, Dhaka, Bangladesh
| | - Tahmina Afroz
- Department of Pharmacy, Faculty of Allied Health Sciences, Daffodil International University, 1207, Dhaka, Bangladesh
| | - Muniruddin Ahmed
- Department of Pharmacy, Faculty of Allied Health Sciences, Daffodil International University, 1207, Dhaka, Bangladesh
| | - Hassan A Hemeg
- Department of Medical Laboratory Technology, College of Applied Medical Sciences, Taibah University, Al-Medinah Al-Monawara, Saudi Arabia
| | - Abdur Rauf
- Department of Chemistry, University of Swabi, Swabi, Khyber Pukhtanukha, Pakistan.
| | - Muthu Thiruvengadam
- Department of Applied Bioscience, College of Life and Environmental Science, Konkuk University, Seoul, 05029, South Korea.
| | - Baskar Venkidasamy
- Department of Oral and Maxillofacial Surgery, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, 600 077, India.
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5
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Stonebraker AR, Hankin R, Kapp KL, Li P, Valentine SJ, Legleiter J. Charge within Nt17 peptides modulates huntingtin aggregation and initial lipid binding events. Biophys Chem 2023; 303:107123. [PMID: 37852163 PMCID: PMC10843285 DOI: 10.1016/j.bpc.2023.107123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 09/22/2023] [Accepted: 10/10/2023] [Indexed: 10/20/2023]
Abstract
Toxic aggregation of pathogenic huntingtin protein (htt) is implicated in Huntington's disease and influenced by various factors, including the first seventeen amino acids at the N-terminus (Nt17) and the presence of lipid membranes. Nt17 has a propensity to form an amphipathic α-helix in the presence of binding partners, which promotes α-helix rich oligomer formation and facilitates htt/lipid interactions. Within Nt17 are multiple sites that are subject to post-translational modification, including acetylation and phosphorylation. Acetylation can occur at lysine 6, 9, and/or 15 while phosphorylation can occur at threonine 3, serine 13, and/or serine 16. Such modifications impact aggregation and lipid binding through the alteration of various intra- and intermolecular interactions. When incubated with htt-exon1(46Q), free Nt17 peptides containing point mutations mimicking acetylation or phosphorylation reduced fibril formation and altered oligomer morphologies. Upon exposure to lipid vesicles, changes to peptide/lipid complexation were observed and peptide-containing oligomers demonstrated reduced lipid interactions.
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Affiliation(s)
- Alyssa R Stonebraker
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, WV 26506, USA
| | - Rachel Hankin
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, WV 26506, USA
| | - Kathryn L Kapp
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, WV 26506, USA
| | - Peng Li
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, WV 26506, USA
| | - Stephen J Valentine
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, WV 26506, USA
| | - Justin Legleiter
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, WV 26506, USA; Rockefeller Neurosciences Institutes, West Virginia University, 1 Medical Center Dr., P.O. Box 9303, Morgantown, WV 26505, USA; Department of Neuroscience, West Virginia University, 1 Medical Center Dr., P.O. Box 9303, Morgantown, WV 26505, USA.
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6
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Thompson LM, Orr HT. HD and SCA1: Tales from two 30-year journeys since gene discovery. Neuron 2023; 111:3517-3530. [PMID: 37863037 PMCID: PMC10842341 DOI: 10.1016/j.neuron.2023.09.036] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 07/21/2023] [Accepted: 09/26/2023] [Indexed: 10/22/2023]
Abstract
One of the more transformative findings in human genetics was the discovery that the expansion of unstable nucleotide repeats underlies a group of inherited neurological diseases. A subset of these unstable repeat neurodegenerative diseases is due to the expansion of a CAG trinucleotide repeat encoding a stretch of glutamines, i.e., the polyglutamine (polyQ) repeat neurodegenerative diseases. Among the CAG/polyQ repeat diseases are Huntington's disease (HD) and spinocerebellar ataxia type 1 (SCA1), in which the expansions are within widely expressed proteins. Although both HD and SCA1 are autosomal dominantly inherited, and both typically cause mid- to late-life-onset movement disorders with cognitive decline, they each are characterized by distinct clinical characteristics and predominant sites of neuropathology. Importantly, the respective affected proteins, Huntingtin (HTT, HD) and Ataxin 1 (ATXN1, SCA1), have unique functions and biological properties. Here, we review HD and SCA1 with a focus on how their disease-specific and shared features may provide informative insights.
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Affiliation(s)
- Leslie M Thompson
- Department of Psychiatry and Human Behavior, Department of Neurobiology and Behavior, Department of Biological Chemistry, Institute of Memory Impairments and Neurological Disorders, Sue and Bill Gross Stem Cell Center, University of California Irvine, Irvine, CA 92697, USA
| | - Harry T Orr
- Department of Laboratory Medicine and Pathology, Institute for Translational Neuroscience, University of Minnesota, Minneapolis and Saint Paul, MN 55455, USA.
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7
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Cariulo C, Martufi P, Verani M, Toledo-Sherman L, Lee R, Dominguez C, Petricca L, Caricasole A. IKBKB reduces huntingtin aggregation by phosphorylating serine 13 via a non-canonical IKK pathway. Life Sci Alliance 2023; 6:e202302006. [PMID: 37553253 PMCID: PMC10410066 DOI: 10.26508/lsa.202302006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 07/27/2023] [Accepted: 07/31/2023] [Indexed: 08/10/2023] Open
Abstract
N-terminal phosphorylation at residues T3 and S13 is believed to have important beneficial implications for the biological and pathological properties of mutant huntingtin, where inhibitor of nuclear factor kappa B kinase subunit beta (IKBKB) was identified as a candidate regulator of huntingtin N-terminal phosphorylation. The paucity of mechanistic information on IKK pathways, together with the lack of sensitive methods to quantify endogenous huntingtin phosphorylation, prevented detailed study of the role of IKBKB in Huntington's disease. Using novel ultrasensitive assays, we demonstrate that IKBKB can regulate endogenous S13 huntingtin phosphorylation in a manner, dependent on its kinase activity and known regulators. We found that the ability of IKBKB to phosphorylate endogenous huntingtin S13 is mediated through a non-canonical interferon regulatory factor3-mediated IKK pathway, distinct from the established involvement of IKBKB in mutant huntingtin's pathological mechanisms mediated via the canonical pathway. Furthermore, increased huntingtin S13 phosphorylation by IKBKB resulted in decreased aggregation of mutant huntingtin in cells, again dependent on its kinase activity. These findings point to a non-canonical IKK pathway linking S13 huntingtin phosphorylation to the pathological properties of mutant huntingtin aggregation, thought to be significant to Huntington's disease.
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Affiliation(s)
- Cristina Cariulo
- Neuroscience Unit, Translational and Discovery Research Department, IRBM S.p.A., Rome, Italy
| | - Paola Martufi
- Neuroscience Unit, Translational and Discovery Research Department, IRBM S.p.A., Rome, Italy
| | - Margherita Verani
- Neuroscience Unit, Translational and Discovery Research Department, IRBM S.p.A., Rome, Italy
| | - Leticia Toledo-Sherman
- Rainwatercf.org Tau Consortium, Rainwater Charitable Foundation, Fort Worth, TX, USA
- UCLA, Department of Neurology, University of California Los Angeles, Los Angeles, CA, USA
| | - Ramee Lee
- CHDI Management/CHDI Foundation, Princeton, NJ, USA
| | | | - Lara Petricca
- Neuroscience Unit, Translational and Discovery Research Department, IRBM S.p.A., Rome, Italy
| | - Andrea Caricasole
- Neuroscience Unit, Translational and Discovery Research Department, IRBM S.p.A., Rome, Italy
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8
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Lemarié FL, Sanders SS, Nguyen Y, Martin DDO, Hayden MR. Full-length huntingtin is palmitoylated at multiple sites and post-translationally myristoylated following caspase-cleavage. Front Physiol 2023; 14:1086112. [PMID: 36711022 PMCID: PMC9880554 DOI: 10.3389/fphys.2023.1086112] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 01/02/2023] [Indexed: 01/15/2023] Open
Abstract
Introduction: Huntington disease is an autosomal dominant neurodegenerative disorder which is caused by a CAG repeat expansion in the HTT gene that codes for an elongated polyglutamine tract in the huntingtin (HTT) protein. Huntingtin is subjected to multiple post-translational modifications which regulate its cellular functions and degradation. We have previously identified a palmitoylation site at cysteine 214 (C214), catalyzed by the enzymes ZDHHC17 and ZDHHC13. Reduced palmitoylation level of mutant huntingtin is linked to toxicity and loss of function. Moreover, we have described N-terminal myristoylation by the N-myristoyltransferases of a short fragment of huntingtin (HTT553-586) at glycine 553 (G553) following proteolysis at aspartate 552 (D552). Results: Here, we show that huntingtin is palmitoylated at numerous cysteines: C105, C433, C3134 and C3144. In addition, we confirm that full-length huntingtin is cleaved at D552 and post-translationally myristoylated at G553. Importantly, blocking caspase cleavage at the critical and pathogenic aspartate 586 (D586) significantly increases posttranslational myristoylation of huntingtin. In turn, myristoylation of huntingtin promotes the co-interaction between C-terminal and N-terminal huntingtin fragments, which is also protective. Discussion: This suggests that the protective effect of inhibiting caspase-cleavage at D586 may be mediated through post-translational myristoylation of huntingtin at G553.
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Lee Y, Kim H, Barker D, Vijayvargia R, Atwal RS, Specht H, Keshishian H, Carr SA, Lee R, Kwak S, Hyun KG, Loupe J, MacDonald ME, Song JJ, Seong IS. Huntingtin turnover: modulation of huntingtin degradation by cAMP-dependent protein kinase A (PKA) phosphorylation of C-HEAT domain Ser2550. Hum Mol Genet 2023; 32:30-45. [PMID: 35908190 DOI: 10.1093/hmg/ddac165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 07/07/2022] [Accepted: 07/12/2022] [Indexed: 01/25/2023] Open
Abstract
Huntington's disease (HD) is a neurodegenerative disorder caused by an inherited unstable HTT CAG repeat that expands further, thereby eliciting a disease process that may be initiated by polyglutamine-expanded huntingtin or a short polyglutamine-product. Phosphorylation of selected candidate residues is reported to mediate polyglutamine-fragment degradation and toxicity. Here to support the discovery of phosphosites involved in the life-cycle of (full-length) huntingtin, we employed mass spectrometry-based phosphoproteomics to systematically identify sites in purified huntingtin and in the endogenous protein by proteomic and phosphoproteomic analyses of members of an HD neuronal progenitor cell panel. Our results bring total huntingtin phosphosites to 95, with more located in the N-HEAT domain relative to numbers in the Bridge and C-HEAT domains. Moreover, phosphorylation of C-HEAT Ser2550 by cAMP-dependent protein kinase (PKA), the top hit in kinase activity screens, was found to hasten huntingtin degradation, such that levels of the catalytic subunit (PRKACA) were inversely related to huntingtin levels. Taken together, these findings highlight categories of phosphosites that merit further study and provide a phosphosite kinase pair (pSer2550-PKA) with which to investigate the biological processes that regulate huntingtin degradation and thereby influence the steady state levels of huntingtin in HD cells.
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Affiliation(s)
- Yejin Lee
- Department of Biological Sciences, KI for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea.,Molecular Neurogenetics Unit, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Neurology, Harvard Medical School, Boston, MA 02114, USA
| | - Hyeongju Kim
- Department of Biological Sciences, KI for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Douglas Barker
- Molecular Neurogenetics Unit, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Neurology, Harvard Medical School, Boston, MA 02114, USA
| | - Ravi Vijayvargia
- Molecular Neurogenetics Unit, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Neurology, Harvard Medical School, Boston, MA 02114, USA
| | - Ranjit Singh Atwal
- Molecular Neurogenetics Unit, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Neurology, Harvard Medical School, Boston, MA 02114, USA
| | - Harrison Specht
- Broad Institute of MIT and Harvard, 7 Cambridge Center, Cambridge, MA 02142, USA
| | - Hasmik Keshishian
- Broad Institute of MIT and Harvard, 7 Cambridge Center, Cambridge, MA 02142, USA
| | - Steven A Carr
- Broad Institute of MIT and Harvard, 7 Cambridge Center, Cambridge, MA 02142, USA
| | - Ramee Lee
- CHDI Management/CHDI Foundation, Princeton, NJ 08540, USA
| | - Seung Kwak
- CHDI Management/CHDI Foundation, Princeton, NJ 08540, USA
| | - Kyung-Gi Hyun
- Molecular Neurogenetics Unit, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Neurology, Harvard Medical School, Boston, MA 02114, USA
| | - Jacob Loupe
- Molecular Neurogenetics Unit, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Neurology, Harvard Medical School, Boston, MA 02114, USA
| | - Marcy E MacDonald
- Molecular Neurogenetics Unit, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Neurology, Harvard Medical School, Boston, MA 02114, USA
| | - Ji-Joon Song
- Department of Biological Sciences, KI for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Ihn Sik Seong
- Molecular Neurogenetics Unit, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Neurology, Harvard Medical School, Boston, MA 02114, USA
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10
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Kim H, Gomez-Pastor R. HSF1 and Its Role in Huntington's Disease Pathology. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1410:35-95. [PMID: 36396925 DOI: 10.1007/5584_2022_742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
PURPOSE OF REVIEW Heat shock factor 1 (HSF1) is the master transcriptional regulator of the heat shock response (HSR) in mammalian cells and is a critical element in maintaining protein homeostasis. HSF1 functions at the center of many physiological processes like embryogenesis, metabolism, immune response, aging, cancer, and neurodegeneration. However, the mechanisms that allow HSF1 to control these different biological and pathophysiological processes are not fully understood. This review focuses on Huntington's disease (HD), a neurodegenerative disease characterized by severe protein aggregation of the huntingtin (HTT) protein. The aggregation of HTT, in turn, leads to a halt in the function of HSF1. Understanding the pathways that regulate HSF1 in different contexts like HD may hold the key to understanding the pathomechanisms underlying other proteinopathies. We provide the most current information on HSF1 structure, function, and regulation, emphasizing HD, and discussing its potential as a biological target for therapy. DATA SOURCES We performed PubMed search to find established and recent reports in HSF1, heat shock proteins (Hsp), HD, Hsp inhibitors, HSF1 activators, and HSF1 in aging, inflammation, cancer, brain development, mitochondria, synaptic plasticity, polyglutamine (polyQ) diseases, and HD. STUDY SELECTIONS Research and review articles that described the mechanisms of action of HSF1 were selected based on terms used in PubMed search. RESULTS HSF1 plays a crucial role in the progression of HD and other protein-misfolding related neurodegenerative diseases. Different animal models of HD, as well as postmortem brains of patients with HD, reveal a connection between the levels of HSF1 and HSF1 dysfunction to mutant HTT (mHTT)-induced toxicity and protein aggregation, dysregulation of the ubiquitin-proteasome system (UPS), oxidative stress, mitochondrial dysfunction, and disruption of the structural and functional integrity of synaptic connections, which eventually leads to neuronal loss. These features are shared with other neurodegenerative diseases (NDs). Currently, several inhibitors against negative regulators of HSF1, as well as HSF1 activators, are developed and hold promise to prevent neurodegeneration in HD and other NDs. CONCLUSION Understanding the role of HSF1 during protein aggregation and neurodegeneration in HD may help to develop therapeutic strategies that could be effective across different NDs.
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Affiliation(s)
- Hyuck Kim
- Department of Neuroscience, School of Medicine, University of Minnesota, Minneapolis, MN, USA
| | - Rocio Gomez-Pastor
- Department of Neuroscience, School of Medicine, University of Minnesota, Minneapolis, MN, USA.
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11
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Proteinopathies: Deciphering Physiology and Mechanisms to Develop Effective Therapies for Neurodegenerative Diseases. Mol Neurobiol 2022; 59:7513-7540. [PMID: 36205914 DOI: 10.1007/s12035-022-03042-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 09/13/2022] [Indexed: 10/10/2022]
Abstract
Neurodegenerative diseases (NDs) are a cluster of diseases marked by progressive neuronal loss, axonal transport blockage, mitochondrial dysfunction, oxidative stress, neuroinflammation, and aggregation of misfolded proteins. NDs are more prevalent beyond the age of 50, and their symptoms often include motor and cognitive impairment. Even though various proteins are involved in different NDs, the mechanisms of protein misfolding and aggregation are very similar. Recently, several studies have discovered that, like prions, these misfolded proteins have the inherent capability of translocation from one neuron to another, thus having far-reaching implications for understanding the processes involved in the onset and progression of NDs, as well as the development of innovative therapy and diagnostic options. These misfolded proteins can also influence the transcription of other proteins and form aggregates, tangles, plaques, and inclusion bodies, which then accumulate in the CNS, leading to neuronal dysfunction and neurodegeneration. This review demonstrates protein misfolding and aggregation in NDs, and similarities and differences between different protein aggregates have been discussed. Furthermore, we have also reviewed the disposal of protein aggregates, the various molecular machinery involved in the process, their regulation, and how these molecular mechanisms are targeted to build innovative therapeutic and diagnostic procedures. In addition, the landscape of various therapeutic interventions for targeting protein aggregation for the effective prevention or treatment of NDs has also been discussed.
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12
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Ahmad A, Uversky VN, Khan RH. Aberrant liquid-liquid phase separation and amyloid aggregation of proteins related to neurodegenerative diseases. Int J Biol Macromol 2022; 220:703-720. [PMID: 35998851 DOI: 10.1016/j.ijbiomac.2022.08.132] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 08/11/2022] [Accepted: 08/19/2022] [Indexed: 11/05/2022]
Abstract
Recent evidence has shown that the processes of liquid-liquid phase separation (LLPS) or liquid-liquid phase transitions (LLPTs) are a crucial and prevalent phenomenon that underlies the biogenesis of numerous membrane-less organelles (MLOs) and biomolecular condensates within the cells. Findings show that processes associated with LLPS play an essential role in physiology and disease. In this review, we discuss the physical and biomolecular factors that contribute to the development of LLPS, the associated functions, as well as their consequences for cell physiology and neurological disorders. Additionally, the finding of mis-regulated proteins, which have long been linked to aggregates in neuropathology, are also known to induce LLPS/LLPTs, prompting a lot of interest in understanding the connection between aberrant phase separation and disorder conditions. Moreover, the methods used in recent and ongoing studies in this field are also explored, as is the possibility that these findings will encourage new lines of inquiry into the molecular causes of neurodegenerative diseases.
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Affiliation(s)
- Azeem Ahmad
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, U.P. 202002, India
| | - Vladimir N Uversky
- Department of Molecular Medicine, Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA; Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Institutskiy pereulok, 9, Dolgoprudny, 141700, Russia.
| | - Rizwan Hasan Khan
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, U.P. 202002, India.
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13
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White A, McGlone A, Gomez-Pastor R. Protein Kinase CK2 and Its Potential Role as a Therapeutic Target in Huntington's Disease. Biomedicines 2022; 10:1979. [PMID: 36009526 PMCID: PMC9406209 DOI: 10.3390/biomedicines10081979] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 08/10/2022] [Accepted: 08/12/2022] [Indexed: 11/17/2022] Open
Abstract
Huntington's Disease (HD) is a devastating neurodegenerative disorder caused by a CAG trinucleotide repeat expansion in the HTT gene, for which no disease modifying therapies are currently available. Much of the recent research has focused on developing therapies to directly lower HTT expression, and while promising, these therapies have presented several challenges regarding administration and efficacy. Another promising therapeutic approach is the modulation of HTT post-translational modifications (PTMs) that are dysregulated in disease and have shown to play a key role in HTT toxicity. Among all PTMs, modulation of HTT phosphorylation has been proposed as an attractive therapeutic option due to the possibility of orally administering specific kinase effectors. One of the kinases described to participate in HTT phosphorylation is Protein Kinase CK2. CK2 has recently emerged as a target for the treatment of several neurological and psychiatric disorders, although its role in HD remains controversial. While pharmacological studies in vitro inhibiting CK2 resulted in reduced HTT phosphorylation and increased toxicity, genetic approaches in mouse models of HD have provided beneficial effects. In this review we discuss potential therapeutic approaches related to the manipulation of HTT-PTMs with special emphasis on the role of CK2 as a therapeutic target in HD.
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Affiliation(s)
| | | | - Rocio Gomez-Pastor
- Department of Neuroscience, School of Medicine, University of Minnesota, Minneapolis, MN 55455, USA
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14
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Adegbuyiro A, Stonebraker AR, Sedighi F, Fan CK, Hodges B, Li P, Valentine SJ, Legleiter J. Oxidation Promotes Distinct Huntingtin Aggregates in the Presence and Absence of Membranes. Biochemistry 2022; 61:1517-1530. [PMID: 35759798 DOI: 10.1021/acs.biochem.2c00212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Expansion of a polyglutamine (polyQ) domain within the first exon of the huntingtin (htt) protein is the underlying cause of Huntington's disease, a genetic neurodegenerative disorder. PolyQ expansion triggers htt aggregation into oligomers, fibrils, and inclusions. The 17 N-terminal amino acids (Nt17) of htt-exon1, which directly precede the polyQ domain enhances polyQ fibrillization and functions as a lipid-binding domain. A variety of post-translational modifications occur within Nt17, including oxidation of two methionine residues. Here, the impact of oxidation within Nt17 on htt aggregation both in the presence and absence of lipid membranes was investigated. Treatment with hydrogen peroxide (H2O2) reduced fibril formation in a dose-dependent manner, resulting in shorter fibrils and an increased oligomer population. With excessive H2O2 treatments, fibrils developed a unique morphological feature around their periphery. In the presence of total brain lipid vesicles, H2O2 impacted fibrillization in a similar manner. That is, oligomerization was promoted at the expense of fibril elongation. The interaction of unoxidized and oxidized htt with supported lipid bilayers was directly observed using in situ atomic force microscopy. Without oxidation, granular htt aggregates developed on the bilayer surface. However, in the presence of H2O2, distinct plateau-like regions initially developed on the bilayer surface that gave way to rougher patches containing granular aggregates. Collectively, these observations suggest that oxidation of methionine residues within Nt17 plays a crucial role in both the aggregation of htt and its ability to interact with lipid surfaces.
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Affiliation(s)
- Adewale Adegbuyiro
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States
| | - Alyssa R Stonebraker
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States
| | - Faezeh Sedighi
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States
| | - Caleb K Fan
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States
| | - Breanna Hodges
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States
| | - Peng Li
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States
| | - Stephen J Valentine
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States
| | - Justin Legleiter
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States.,Rockefeller Neurosciences Institutes, West Virginia University, 1 Medical Center Dr., P.O. Box 9303, Morgantown, West Virginia 26505, United States.,Department of Neuroscience, West Virginia University, 1 Medical Center Dr., P.O. Box 9303, Morgantown, West Virginia 26505, United States
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15
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Ratovitski T, Jiang M, O'Meally RN, Rauniyar P, Chighladze E, Faragó A, Kamath SV, Jin J, Shevelkin AV, Cole RN, Ross CA. Interaction of huntingtin with PRMTs and its subsequent arginine methylation affects HTT solubility, phase transition behavior and neuronal toxicity. Hum Mol Genet 2022; 31:1651-1672. [PMID: 34888656 PMCID: PMC9122652 DOI: 10.1093/hmg/ddab351] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 11/16/2021] [Accepted: 12/02/2021] [Indexed: 11/12/2022] Open
Abstract
Huntington's disease (HD) is an incurable neurodegenerative disorder caused by a CAG expansion in the huntingtin gene (HTT). Post-translational modifications of huntingtin protein (HTT), such as phosphorylation, acetylation and ubiquitination, have been implicated in HD pathogenesis. Arginine methylation/dimethylation is an important modification with an emerging role in neurodegeneration; however, arginine methylation of HTT remains largely unexplored. Here we report nearly two dozen novel arginine methylation/dimethylation sites on the endogenous HTT from human and mouse brain and human cells suggested by mass spectrometry with data-dependent acquisition. Targeted quantitative mass spectrometry identified differential arginine methylation at specific sites in HD patient-derived striatal precursor cell lines compared to normal controls. We found that HTT can interact with several type I protein arginine methyltransferases (PRMTs) via its N-terminal domain. Using a combination of in vitro methylation and cell-based experiments, we identified PRMT4 (CARM1) and PRMT6 as major enzymes methylating HTT at specific arginines. Alterations of these methylation sites had a profound effect on biochemical properties of HTT rendering it less soluble in cells and affected its liquid-liquid phase separation and phase transition patterns in vitro. We found that expanded HTT 1-586 fragment can form liquid-like assemblies, which converted into solid-like assemblies when the R200/205 methylation sites were altered. Methyl-null alterations increased HTT toxicity to neuronal cells, while overexpression of PRMT 4 and 6 was beneficial for neuronal survival. Thus, arginine methylation pathways that involve specific HTT-modifying PRMT enzymes and modulate HTT biochemical and toxic properties could provide targets for HD-modifying therapies.
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Affiliation(s)
- Tamara Ratovitski
- To whom correspondence should be addressed at: or Christopher Ross, Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, 600 North Wolfe Street, CMSC 9-123, 600 North Wolfe Street, Baltimore, MD 21287, USA. Fax: +1 4106140013; ,
| | | | | | | | - Ekaterine Chighladze
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Anikó Faragó
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Siddhi V Kamath
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Jing Jin
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Alexey V Shevelkin
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Robert N Cole
- Mass Spectrometry and Proteomics Facility, Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Christopher A Ross
- To whom correspondence should be addressed at: or Christopher Ross, Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, 600 North Wolfe Street, CMSC 9-123, 600 North Wolfe Street, Baltimore, MD 21287, USA. Fax: +1 4106140013; ,
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Abstract
Amyloids are protein aggregates bearing a highly ordered cross β structural motif, which may be functional but are mostly pathogenic. Their formation, deposition in tissues and consequent organ dysfunction is the central event in amyloidogenic diseases. Such protein aggregation may be brought about by conformational changes, and much attention has been directed toward factors like metal binding, post-translational modifications, mutations of protein etc., which eventually affect the reactivity and cytotoxicity of the associated proteins. Over the past decade, a global effort from different groups working on these misfolded/unfolded proteins/peptides has revealed that the amino acid residues in the second coordination sphere of the active sites of amyloidogenic proteins/peptides cause changes in H-bonding pattern or protein-protein interactions, which dramatically alter the structure and reactivity of these proteins/peptides. These second sphere effects not only determine the binding of transition metals and cofactors, which define the pathology of some of these diseases, but also change the mechanism of redox reactions catalyzed by these proteins/peptides and form the basis of oxidative damage associated with these amyloidogenic diseases. The present review seeks to discuss such second sphere modifications and their ramifications in the etiopathology of some representative amyloidogenic diseases like Alzheimer's disease (AD), type 2 diabetes mellitus (T2Dm), Parkinson's disease (PD), Huntington's disease (HD), and prion diseases.
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Affiliation(s)
- Madhuparna Roy
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B, Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India
| | - Arnab Kumar Nath
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B, Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India
| | - Ishita Pal
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B, Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India
| | - Somdatta Ghosh Dey
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B, Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India
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17
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Nuclear and cytoplasmic huntingtin inclusions exhibit distinct biochemical composition, interactome and ultrastructural properties. Nat Commun 2021; 12:6579. [PMID: 34772920 PMCID: PMC8589980 DOI: 10.1038/s41467-021-26684-z] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 10/11/2021] [Indexed: 12/20/2022] Open
Abstract
Despite the strong evidence linking the aggregation of the Huntingtin protein (Htt) to the pathogenesis of Huntington's disease (HD), the mechanisms underlying Htt aggregation and neurodegeneration remain poorly understood. Herein, we investigated the ultrastructural properties and protein composition of Htt cytoplasmic and nuclear inclusions in mammalian cells and primary neurons overexpressing mutant exon1 of the Htt protein. Our findings provide unique insight into the ultrastructural properties of cytoplasmic and nuclear Htt inclusions and their mechanisms of formation. We show that Htt inclusion formation and maturation are complex processes that, although initially driven by polyQ-dependent Htt aggregation, also involve the polyQ and PRD domain-dependent sequestration of lipids and cytoplasmic and cytoskeletal proteins related to HD dysregulated pathways; the recruitment and accumulation of remodeled or dysfunctional membranous organelles, and the impairment of the protein quality control and degradation machinery. We also show that nuclear and cytoplasmic Htt inclusions exhibit distinct biochemical compositions and ultrastructural properties, suggesting different mechanisms of aggregation and toxicity.
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18
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Lemarié FL, Caron NS, Sanders SS, Schmidt ME, Nguyen YTN, Ko S, Xu X, Pouladi MA, Martin DDO, Hayden MR. Rescue of aberrant huntingtin palmitoylation ameliorates mutant huntingtin-induced toxicity. Neurobiol Dis 2021; 158:105479. [PMID: 34390831 DOI: 10.1016/j.nbd.2021.105479] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Revised: 07/29/2021] [Accepted: 08/09/2021] [Indexed: 01/14/2023] Open
Abstract
Huntington disease (HD) is a neurodegenerative disorder caused by a CAG expansion in the HTT gene that codes for an elongated polyglutamine tract in the huntingtin (HTT) protein. HTT is subject to multiple post-translational modifications (PTMs) that regulate its cellular function. Mutating specific PTM sites within mutant HTT (mHTT) in HD mouse models can modulate disease phenotypes, highlighting the key role of HTT PTMs in the pathogenesis of HD. These findings have led to increased interest in developing small molecules to modulate HTT PTMs in order to decrease mHTT toxicity. However, the therapeutic efficacy of pharmacological modulation of HTT PTMs in preclinical HD models remains largely unknown. HTT is palmitoylated at cysteine 214 by the huntingtin-interacting protein 14 (HIP14 or ZDHHC17) and 14-like (HIP14L or ZDHHC13) acyltransferases. Here, we assessed if HTT palmitoylation should be regarded as a therapeutic target to treat HD by (1) investigating palmitoylation dysregulation in rodent and human HD model systems, (2) measuring the impact of mHTT-lowering therapy on brain palmitoylation, and (3) evaluating if HTT palmitoylation can be pharmacologically modulated. We show that palmitoylation of mHTT and some HIP14/HIP14L-substrates is decreased early in multiple HD mouse models, and that mHTT palmitoylation decreases further with aging. Lowering mHTT in the brain of YAC128 mice is not sufficient to rescue aberrant palmitoylation. However, we demonstrate that mHTT palmitoylation can be normalized in COS-7 cells, in YAC128 cortico-striatal primary neurons and HD patient-derived lymphoblasts using an acyl-protein thioesterase (APT) inhibitor. Moreover, we show that modulating palmitoylation reduces mHTT aggregation and mHTT-induced cytotoxicity in COS-7 cells and YAC128 neurons.
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Affiliation(s)
- Fanny L Lemarié
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute, University of British Columbia, Vancouver, Canada
| | - Nicholas S Caron
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute, University of British Columbia, Vancouver, Canada
| | - Shaun S Sanders
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute, University of British Columbia, Vancouver, Canada; Department of Molecular and Cellular Biology, University of Guelph, Guelph, Canada
| | - Mandi E Schmidt
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute, University of British Columbia, Vancouver, Canada
| | - Yen T N Nguyen
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute, University of British Columbia, Vancouver, Canada
| | - Seunghyun Ko
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute, University of British Columbia, Vancouver, Canada
| | - Xiaohong Xu
- Department of Neurology and Stroke Center, The First Affiliated Hospital, Jinan University, Guangzhou, China; Translational Laboratory in Genetic Medicine, Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Mahmoud A Pouladi
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute, University of British Columbia, Vancouver, Canada; Translational Laboratory in Genetic Medicine, Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Dale D O Martin
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute, University of British Columbia, Vancouver, Canada; Department of Biology, University of Waterloo, Waterloo, Canada
| | - Michael R Hayden
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute, University of British Columbia, Vancouver, Canada.
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Chiki A, Zhang Z, Rajasekhar K, Abriata LA, Rostami I, Krapp LF, Boudeffa D, Dal Peraro M, Lashuel HA. Investigating Crosstalk Among PTMs Provides Novel Insight Into the Structural Basis Underlying the Differential Effects of Nt17 PTMs on Mutant Httex1 Aggregation. Front Mol Biosci 2021; 8:686086. [PMID: 34381813 PMCID: PMC8352439 DOI: 10.3389/fmolb.2021.686086] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 07/06/2021] [Indexed: 01/24/2023] Open
Abstract
Post-translational modifications (PTMs) within the first 17 amino acids (Nt17) of the Huntingtin protein (Htt) have been shown to inhibit the aggregation and attenuate the toxicity of mutant Htt proteins in vitro and in various models of Huntington’s disease. Here, we expand on these studies by investigating the effect of methionine eight oxidation (oxM8) and its crosstalk with lysine 6 acetylation (AcK6) or threonine 3 phosphorylation (pT3) on the aggregation of mutant Httex1 (mHttex1). We show that M8 oxidation delays but does not inhibit the aggregation and has no effect on the final morphologies of mHttex1aggregates. The presence of both oxM8 and AcK6 resulted in dramatic inhibition of Httex1 fibrillization. Circular dichroism spectroscopy and molecular dynamics simulation studies show that PTMs that lower the mHttex1 aggregation rate (oxM8, AcK6/oxM8, pT3, pT3/oxM8, and pS13) result in increased population of a short N-terminal helix (first eight residues) in Nt17 or decreased abundance of other helical forms, including long helix and short C-terminal helix. PTMs that did not alter the aggregation rate (AcK6) of mHttex1 exhibit a similar distribution of helical conformation as the unmodified peptides. These results show that the relative abundance of N- vs. C-terminal helical conformations and long helices, rather than the overall helicity of Nt17, better explains the effect of different Nt17 PTMs on mHttex1; thus, explaining the lack of correlation between the effect of PTMs on the overall helicity of Nt17 and mHttex1 aggregation in vitro. Taken together, our results provide novel structural insight into the differential effects of single PTMs and crosstalk between different PTMs in regulating mHttex1 aggregation.
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Affiliation(s)
- Anass Chiki
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, School of Life Sciences, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Zhidian Zhang
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, School of Life Sciences, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.,Laboratory for Biomolecular Modeling, School of Life Sciences, Institute of Bioengineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Kolla Rajasekhar
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, School of Life Sciences, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Luciano A Abriata
- Laboratory for Biomolecular Modeling, School of Life Sciences, Institute of Bioengineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Iman Rostami
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, School of Life Sciences, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.,Laboratory of Biomolecular Research, Department of Biology and Chemistry, Paul Scherrer Institute, Villigen, Switzerland
| | - Lucien F Krapp
- Laboratory for Biomolecular Modeling, School of Life Sciences, Institute of Bioengineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Driss Boudeffa
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, School of Life Sciences, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Matteo Dal Peraro
- Laboratory for Biomolecular Modeling, School of Life Sciences, Institute of Bioengineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Hilal A Lashuel
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, School of Life Sciences, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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20
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Marquette A, Aisenbrey C, Bechinger B. Membrane Interactions Accelerate the Self-Aggregation of Huntingtin Exon 1 Fragments in a Polyglutamine Length-Dependent Manner. Int J Mol Sci 2021; 22:ijms22136725. [PMID: 34201610 PMCID: PMC8268948 DOI: 10.3390/ijms22136725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 06/07/2021] [Accepted: 06/18/2021] [Indexed: 12/04/2022] Open
Abstract
The accumulation of aggregated protein is a typical hallmark of many human neurodegenerative disorders, including polyglutamine-related diseases such as chorea Huntington. Misfolding of the amyloidogenic proteins gives rise to self-assembled complexes and fibres. The huntingtin protein is characterised by a segment of consecutive glutamines which, when exceeding ~ 37 residues, results in the occurrence of the disease. Furthermore, it has also been demonstrated that the 17-residue amino-terminal domain of the protein (htt17), located upstream of this polyglutamine tract, strongly correlates with aggregate formation and pathology. Here, we demonstrate that membrane interactions strongly accelerate the oligomerisation and β-amyloid fibril formation of htt17-polyglutamine segments. By using a combination of biophysical approaches, the kinetics of fibre formation is investigated and found to be strongly dependent on the presence of lipids, the length of the polyQ expansion, and the polypeptide-to-lipid ratio. Finally, the implications for therapeutic approaches are discussed.
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Affiliation(s)
- Arnaud Marquette
- Chemistry Institute UMR7177, University of Strasbourg/CNRS, 67000 Strasbourg, France; (A.M.); (C.A.)
| | - Christopher Aisenbrey
- Chemistry Institute UMR7177, University of Strasbourg/CNRS, 67000 Strasbourg, France; (A.M.); (C.A.)
| | - Burkhard Bechinger
- Chemistry Institute UMR7177, University of Strasbourg/CNRS, 67000 Strasbourg, France; (A.M.); (C.A.)
- Insitut Universitaire de France, 75005 Paris, France
- Correspondence:
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21
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When Good Kinases Go Rogue: GSK3, p38 MAPK and CDKs as Therapeutic Targets for Alzheimer's and Huntington's Disease. Int J Mol Sci 2021; 22:ijms22115911. [PMID: 34072862 PMCID: PMC8199025 DOI: 10.3390/ijms22115911] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 05/26/2021] [Accepted: 05/28/2021] [Indexed: 01/18/2023] Open
Abstract
Alzheimer's disease (AD) is a mostly sporadic brain disorder characterized by cognitive decline resulting from selective neurodegeneration in the hippocampus and cerebral cortex whereas Huntington's disease (HD) is a monogenic inherited disorder characterized by motor abnormalities and psychiatric disturbances resulting from selective neurodegeneration in the striatum. Although there have been numerous clinical trials for these diseases, they have been unsuccessful. Research conducted over the past three decades by a large number of laboratories has demonstrated that abnormal actions of common kinases play a key role in the pathogenesis of both AD and HD as well as several other neurodegenerative diseases. Prominent among these kinases are glycogen synthase kinase (GSK3), p38 mitogen-activated protein kinase (MAPK) and some of the cyclin-dependent kinases (CDKs). After a brief summary of the molecular and cell biology of AD and HD this review covers what is known about the role of these three groups of kinases in the brain and in the pathogenesis of the two neurodegenerative disorders. The potential of targeting GSK3, p38 MAPK and CDKS as effective therapeutics is also discussed as is a brief discussion on the utilization of recently developed drugs that simultaneously target two or all three of these groups of kinases. Multi-kinase inhibitors either by themselves or in combination with strategies currently being used such as immunotherapy or secretase inhibitors for AD and knockdown for HD could represent a more effective therapeutic approach for these fatal neurodegenerative diseases.
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22
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Chiki A, Ricci J, Hegde R, Abriata LA, Reif A, Boudeffa D, Lashuel HA. Site-Specific Phosphorylation of Huntingtin Exon 1 Recombinant Proteins Enabled by the Discovery of Novel Kinases. Chembiochem 2021; 22:217-231. [PMID: 32805086 PMCID: PMC8698011 DOI: 10.1002/cbic.202000508] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 08/17/2020] [Indexed: 12/20/2022]
Abstract
Post-translational modifications (PTMs) within the first 17 amino acids (Nt17) of exon 1 of the Huntingtin protein (Httex1) play important roles in modulating its cellular properties and functions in health and disease. In particular, phosphorylation of threonine and serine residues (T3, S13, and/or S16) has been shown to inhibit Htt aggregation in vitro and inclusion formation in cellular and animal models of Huntington's disease (HD). In this paper, we describe a new and simple methodology for producing milligram quantities of highly pure wild-type or mutant Httex1 proteins that are site-specifically phosphorylated at T3 or at both S13 and S16. This advance was enabled by 1) the discovery and validation of novel kinases that efficiently phosphorylate Httex1 at S13 and S16 (TBK1), at T3 (GCK) or T3 and S13 (TNIK and HGK), and 2) the development of an efficient methodology for producing recombinant native Httex1 proteins by using a SUMO-fusion expression and purification strategy.[26] As a proof of concept, we demonstrate how this method can be applied to produce Httex1 proteins that are both site-specifically phosphorylated and fluorescently or isotopically labeled. Together, these advances should increase access to these valuable tools and expand the range of methods and experimental approaches that can be used to elucidate the mechanisms by which phosphorylation influences Httex1 or HTT structure, aggregation, interactome, and function(s) in health and disease.
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Affiliation(s)
- Anass Chiki
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, School of Life Sciences Brain Mind InstituteEcole Polytechnique Fédérale de Lausanne (EPFL)Station 191015LausanneSwitzerland
| | - Jonathan Ricci
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, School of Life Sciences Brain Mind InstituteEcole Polytechnique Fédérale de Lausanne (EPFL)Station 191015LausanneSwitzerland
| | - Ramanath Hegde
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, School of Life Sciences Brain Mind InstituteEcole Polytechnique Fédérale de Lausanne (EPFL)Station 191015LausanneSwitzerland
| | - Luciano A. Abriata
- Protein Production and Structure Core Facility and Laboratory for Biomolecular ModelingEcole Polytechnique Fédérale de Lausanne (EPFL) and Swiss Institute of Bioinformatics (SIB)1015LausanneSwitzerland
| | - Andreas Reif
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, School of Life Sciences Brain Mind InstituteEcole Polytechnique Fédérale de Lausanne (EPFL)Station 191015LausanneSwitzerland
| | - Driss Boudeffa
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, School of Life Sciences Brain Mind InstituteEcole Polytechnique Fédérale de Lausanne (EPFL)Station 191015LausanneSwitzerland
| | - Hilal A. Lashuel
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, School of Life Sciences Brain Mind InstituteEcole Polytechnique Fédérale de Lausanne (EPFL)Station 191015LausanneSwitzerland
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23
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Groover SE, Beasley M, Ramamurthy V, Legleiter J. Phosphomimetic Mutations Impact Huntingtin Aggregation in the Presence of a Variety of Lipid Systems. Biochemistry 2020; 59:4681-4693. [PMID: 33256402 DOI: 10.1021/acs.biochem.0c00788] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Huntington's disease (HD) is a neurodegenerative disorder caused by the abnormal expansion of a polyglutamine (polyQ) tract in the first exon of the htt protein (htt). PolyQ expansion triggers the aggregation of htt into a variety of structures, including oligomers and fibrils. This aggregation is impacted by the first 17 N-terminal amino acids (Nt17) of htt that directly precedes the polyQ domain. Beyond impacting aggregation, Nt17 associates with lipid membranes by forming an amphipathic α-helix. Post-translational modifications within Nt17 are known to modify HD pathology, and in particular, phosphorylation at T3, S13, and/or S16 retards fibrillization and ameliorates the phenotype in HD models. Due to Nt17's propensity to interact with lipid membranes, the impact of introducing phosphomimetic mutations (T3D, S13D, and S16D) into htt-exon1 on aggregation in the presence of a variety of model lipid membranes (total brain lipid extract, 1-palmitoyl-2-oleoyl-glycero-3-phosphatidylcholine, and 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-1'-rac-glycerol) was investigated. Phosphomimetic mutations altered htt's interaction with and aggregation in the presence of lipids; however, this was dependent on the lipid system.
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Affiliation(s)
- Sharon E Groover
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States
| | - Maryssa Beasley
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States
| | - Visvanathan Ramamurthy
- Department of Ophthalmology, West Virginia University, Morgantown, West Virginia 26506, United States.,Department of Biochemistry, West Virginia University, Morgantown, West Virginia 26506, United States.,Rockefeller Neurosciences Institutes, West Virginia University, 1 Medical Center Drive, P.O. Box 9303, Morgantown, West Virginia 26505, United States
| | - Justin Legleiter
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States.,Rockefeller Neurosciences Institutes, West Virginia University, 1 Medical Center Drive, P.O. Box 9303, Morgantown, West Virginia 26505, United States.,Department of Neuroscience, West Virginia University, 1 Medical Center Drive, P.O. Box 9303, Morgantown, West Virginia 26505, United States
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Lipid headgroups alter huntingtin aggregation on membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1863:183497. [PMID: 33130095 DOI: 10.1016/j.bbamem.2020.183497] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 10/09/2020] [Accepted: 10/12/2020] [Indexed: 12/13/2022]
Abstract
Huntington's Disease is a fatal neurodegenerative disorder caused by expansion of a glutamine repeat region (polyQ) beyond a critical threshold within exon1 of the huntingtin protein (htt). As a consequence of polyQ expansion, htt associates into a variety of aggregate species that are thought to underlie cellular toxicity. Within cells, htt associates with numerous membranous organelles and surfaces that exert influence on the aggregation process. In particular, the first 17 amino acids at the N-terminus of htt (Nt17) serve as a lipid-binding domain that is intrinsically disordered in bulk solution but adopts an amphipathic α-helical structure upon binding membranes. Beyond this, Nt17 is implicated in initiating htt fibrillization. As the interaction between Nt17 and lipid membranes is likely influenced by lipid properties, the impact of lipid headgroups on htt-exon1 aggregation, membrane activity, and the ability to form protein:lipid complexes was determined. Htt-exon1 with a disease-length polyQ domain (46Q) was exposed to lipid vesicles comprised of lipids with either zwitterionic (POPC and POPE) or anionic (POPG and POPS) headgroups. With zwitterionic head groups, large lipid to peptide ratios were required to have a statistically significant impact on htt aggregation. Anionic lipids enhanced htt fibrillization, even at low lipid:protein ratios, and this was accompanied by changes in aggregate morphology. Despite the larger impact of anionic lipids, htt-exon1(46Q) was more membrane active with zwitterionic lipid systems. The ability of Nt17 to form complexes with lipids was also mediated by lipid headgroups as zwitterionic ionic lipids more readily associated with multimeric forms of Nt17 in comparison with anionic lipids. Collectively, these results highlight the complexity of htt/membrane interactions and the resulting impact on the aggregation process.
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pS421 huntingtin modulates mitochondrial phenotypes and confers neuroprotection in an HD hiPSC model. Cell Death Dis 2020; 11:809. [PMID: 32978366 PMCID: PMC7519662 DOI: 10.1038/s41419-020-02983-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 09/02/2020] [Accepted: 09/04/2020] [Indexed: 12/13/2022]
Abstract
Huntington disease (HD) is a hereditary neurodegenerative disorder caused by mutant huntingtin (mHTT). Phosphorylation at serine-421 (pS421) of mHTT has been shown to be neuroprotective in cellular and rodent models. However, the genetic context of these models differs from that of HD patients. Here we employed human pluripotent stem cells (hiPSCs), which express endogenous full-length mHTT. Using genome editing, we generated isogenic hiPSC lines in which the S421 site in mHTT has been mutated into a phospho-mimetic aspartic acid (S421D) or phospho-resistant alanine (S421A). We observed that S421D, rather than S421A, confers neuroprotection in hiPSC-derived neural cells. Although we observed no effect of S421D on mHTT clearance or axonal transport, two aspects previously reported to be impacted by phosphorylation of mHTT at S421, our analysis revealed modulation of several aspects of mitochondrial form and function. These include mitochondrial surface area, volume, and counts, as well as improved mitochondrial membrane potential and oxidative phosphorylation. Our study validates the protective role of pS421 on mHTT and highlights a facet of the relationship between mHTT and mitochondrial changes in the context of human physiology with potential relevance to the pathogenesis of HD.
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26
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Jung T, Shin B, Tamo G, Kim H, Vijayvargia R, Leitner A, Marcaida MJ, Astorga-Wells J, Jung R, Aebersold R, Peraro MD, Hebert H, Seong IS, Song JJ. The Polyglutamine Expansion at the N-Terminal of Huntingtin Protein Modulates the Dynamic Configuration and Phosphorylation of the C-Terminal HEAT Domain. Structure 2020; 28:1035-1050.e8. [PMID: 32668197 PMCID: PMC11059206 DOI: 10.1016/j.str.2020.06.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 04/01/2020] [Accepted: 06/23/2020] [Indexed: 11/15/2022]
Abstract
The polyQ expansion in huntingtin protein (HTT) is the prime cause of Huntington's disease (HD). The recent cryoelectron microscopy (cryo-EM) structure of HTT-HAP40 complex provided the structural information on its HEAT-repeat domains. Here, we present analyses of the impact of polyQ length on the structure and function of HTT via an integrative structural and biochemical approach. The cryo-EM analysis of normal (Q23) and disease (Q78) type HTTs shows that the structures of apo HTTs significantly differ from the structure of HTT in a HAP40 complex and that the polyQ expansion induces global structural changes in the relative movements among the HTT domains. In addition, we show that the polyQ expansion alters the phosphorylation pattern across HTT and that Ser2116 phosphorylation in turn affects the global structure and function of HTT. These results provide a molecular basis for the effect of the polyQ segment on HTT structure and activity, which may be important for HTT pathology.
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Affiliation(s)
- Taeyang Jung
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), KI for the BioCentury, Daejeon 34141, Korea; School of Engineering Sciences in Chemistry, Biotechnology and Health, Department of Biomedical Engineering and Health Systems, KTH Royal Institute of Technology, 141 52 Huddinge, Sweden; Department of Biosciences and Nutrition, Karolinska Institutet, 141 83 Huddinge, Sweden
| | - Baehyun Shin
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Neurology, Harvard Medical School, Boston, MA 02114, USA
| | - Giorgio Tamo
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Hyeongju Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), KI for the BioCentury, Daejeon 34141, Korea
| | - Ravi Vijayvargia
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Neurology, Harvard Medical School, Boston, MA 02114, USA
| | - Alexander Leitner
- Department of Biology, Institute of Molecular Systems Biology, ETH Zürich, 8093 Zürich, Switzerland
| | - Maria J Marcaida
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Juan Astorga-Wells
- Department of Medical Biochemistry & Biophysics, Karolinska Institutet, 171 65 Solna, Sweden; HDxperts AB, 183 48 Täby, Sweden
| | - Roy Jung
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Neurology, Harvard Medical School, Boston, MA 02114, USA
| | - Ruedi Aebersold
- Department of Biology, Institute of Molecular Systems Biology, ETH Zürich, 8093 Zürich, Switzerland; Faculty of Science, University of Zürich, Zürich, Switzerland
| | - Matteo Dal Peraro
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
| | - Hans Hebert
- School of Engineering Sciences in Chemistry, Biotechnology and Health, Department of Biomedical Engineering and Health Systems, KTH Royal Institute of Technology, 141 52 Huddinge, Sweden; Department of Biosciences and Nutrition, Karolinska Institutet, 141 83 Huddinge, Sweden.
| | - Ihn Sik Seong
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Neurology, Harvard Medical School, Boston, MA 02114, USA.
| | - Ji-Joon Song
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), KI for the BioCentury, Daejeon 34141, Korea.
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27
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Hegde RN, Chiki A, Petricca L, Martufi P, Arbez N, Mouchiroud L, Auwerx J, Landles C, Bates GP, Singh-Bains MK, Dragunow M, Curtis MA, Faull RL, Ross CA, Caricasole A, Lashuel HA. TBK1 phosphorylates mutant Huntingtin and suppresses its aggregation and toxicity in Huntington's disease models. EMBO J 2020; 39:e104671. [PMID: 32757223 PMCID: PMC7459410 DOI: 10.15252/embj.2020104671] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 06/09/2020] [Accepted: 06/16/2020] [Indexed: 12/17/2022] Open
Abstract
Phosphorylation of the N‐terminal domain of the huntingtin (HTT) protein has emerged as an important regulator of its localization, structure, aggregation, clearance and toxicity. However, validation of the effect of bona fide phosphorylation in vivo and assessing the therapeutic potential of targeting phosphorylation for the treatment of Huntington's disease (HD) require the identification of the enzymes that regulate HTT phosphorylation. Herein, we report the discovery and validation of a kinase, TANK‐binding kinase 1 (TBK1), that efficiently phosphorylates full‐length and N‐terminal HTT fragments in vitro (at S13/S16), in cells (at S13) and in vivo. TBK1 expression in HD models (cells, primary neurons, and Caenorhabditis elegans) increases mutant HTT exon 1 phosphorylation and reduces its aggregation and cytotoxicity. We demonstrate that the TBK1‐mediated neuroprotective effects are due to phosphorylation‐dependent inhibition of mutant HTT exon 1 aggregation and an increase in autophagic clearance of mutant HTT. These findings suggest that upregulation and/or activation of TBK1 represents a viable strategy for the treatment of HD by simultaneously lowering mutant HTT levels and blocking its aggregation.
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Affiliation(s)
- Ramanath Narayana Hegde
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Anass Chiki
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Lara Petricca
- Department of Neuroscience, IRBM Science Park, Rome, Italy
| | - Paola Martufi
- Department of Neuroscience, IRBM Science Park, Rome, Italy
| | - Nicolas Arbez
- Division of Neurobiology, Department of Psychiatry and Departments of Neurology, Neuroscience and Pharmacology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Laurent Mouchiroud
- Laboratory of Integrative and Systems Physiology, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Johan Auwerx
- Laboratory of Integrative and Systems Physiology, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Christian Landles
- Huntington's Disease Centre, Department of Neurodegenerative Disease and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, University College London, London, UK
| | - Gillian P Bates
- Huntington's Disease Centre, Department of Neurodegenerative Disease and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, University College London, London, UK
| | - Malvindar K Singh-Bains
- Centre for Brain Research, Department of Anatomy and Medical Imaging, University of Auckland, Auckland, New Zealand
| | - Mike Dragunow
- Centre for Brain Research, Department of Pharmacology and Clinical Pharmacology, University of Auckland, Auckland, New Zealand
| | - Maurice A Curtis
- Centre for Brain Research, Department of Anatomy and Medical Imaging, University of Auckland, Auckland, New Zealand
| | - Richard Lm Faull
- Centre for Brain Research, Department of Anatomy and Medical Imaging, University of Auckland, Auckland, New Zealand
| | - Christopher A Ross
- Division of Neurobiology, Department of Psychiatry and Departments of Neurology, Neuroscience and Pharmacology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | | | - Hilal A Lashuel
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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Lontay B, Kiss A, Virág L, Tar K. How Do Post-Translational Modifications Influence the Pathomechanistic Landscape of Huntington's Disease? A Comprehensive Review. Int J Mol Sci 2020; 21:ijms21124282. [PMID: 32560122 PMCID: PMC7349273 DOI: 10.3390/ijms21124282] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 06/11/2020] [Accepted: 06/13/2020] [Indexed: 12/15/2022] Open
Abstract
Huntington’s disease (HD) is an autosomal dominant inherited neurodegenerative disorder characterized by the loss of motor control and cognitive ability, which eventually leads to death. The mutant huntingtin protein (HTT) exhibits an expansion of a polyglutamine repeat. The mechanism of pathogenesis is still not fully characterized; however, evidence suggests that post-translational modifications (PTMs) of HTT and upstream and downstream proteins of neuronal signaling pathways are involved. The determination and characterization of PTMs are essential to understand the mechanisms at work in HD, to define possible therapeutic targets better, and to challenge the scientific community to develop new approaches and methods. The discovery and characterization of a panoply of PTMs in HTT aggregation and cellular events in HD will bring us closer to understanding how the expression of mutant polyglutamine-containing HTT affects cellular homeostasis that leads to the perturbation of cell functions, neurotoxicity, and finally, cell death. Hence, here we review the current knowledge on recently identified PTMs of HD-related proteins and their pathophysiological relevance in the formation of abnormal protein aggregates, proteolytic dysfunction, and alterations of mitochondrial and metabolic pathways, neuroinflammatory regulation, excitotoxicity, and abnormal regulation of gene expression.
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Affiliation(s)
- Beata Lontay
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (B.L.); (A.K.); (L.V.)
| | - Andrea Kiss
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (B.L.); (A.K.); (L.V.)
| | - László Virág
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (B.L.); (A.K.); (L.V.)
- MTA-DE Cell Biology and Signaling Research Group, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary
| | - Krisztina Tar
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary; (B.L.); (A.K.); (L.V.)
- Correspondence: ; Tel.: +36-52-412345
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Protein changes in synaptosomes of Huntington's disease knock-in mice are dependent on age and brain region. Neurobiol Dis 2020; 141:104950. [PMID: 32439598 DOI: 10.1016/j.nbd.2020.104950] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 03/19/2020] [Accepted: 05/16/2020] [Indexed: 12/15/2022] Open
Abstract
Molecular changes at synapses are thought to underly the deficits in motor and cognitive dysfunction seen in Huntington's disease (HD). Previously we showed in synaptosome preparations age dependent changes in levels of selected proteins examined by western blot assay in the striatum of Q140/Q140 HD mice. To assess if CAG repeat length influenced protein changes at the synapse, we examined synaptosomes from 6-month old heterozygote HD mice with CAG repeat lengths ranging from 50 to 175. Analysis of 19 selected proteins showed that increasing CAG repeat length in huntingtin (HTT) increased the number of affected proteins in HD striatal synaptosomes. Moreover, SDS-soluble total HTT (WT plus mutant HTT) and pThr3 HTT were reduced with increasing CAG repeat length, and there was no pSer421 mutant HTT detected in any HD mice. A LC-MS/MS and bioinfomatics study of synaptosomes from 2 and 6-month old striatum and cortex of Q140/Q7 HD mice showed enrichment of synaptic proteins and an influence of age, gender and brain region on the number of protein changes. HD striatum at 6 months had the most protein changes that included many HTT protein interactors, followed by 2-month old HD striatum, 2-month old HD cortex and 6-month HD cortex. SDS-insoluble mutant HTT was detected in HD striatal synaptosomes consistent with the presence of aggregates. Proteins changed in cortex differed from those in striatum. Pathways affected in HD striatal synaptosomes that were not identified in whole striatal lysates of the same HD mouse model included axon guidance, focal adhesion, neurotrophin signaling, regulation of actin cytoskeleton, endocytosis, and synaptic vesicle cycle. Results suggest that synaptosomes prepared from HD mice are highly informative for monitoring protein changes at the synapse and may be preferred for assessing the effects of experimental therapies on synaptic function in HD.
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Sedighi F, Adegbuyiro A, Legleiter J. SUMOylation Prevents Huntingtin Fibrillization and Localization onto Lipid Membranes. ACS Chem Neurosci 2020; 11:328-343. [PMID: 31880908 DOI: 10.1021/acschemneuro.9b00509] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Huntington's disease (HD), a genetic neurodegenerative disease, is caused by an expanded polyglutamine (polyQ) domain in the first exon of the huntingtin protein (htt). PolyQ expansion destabilizes protein structure, resulting in aggregation into a variety of oligomers, protofibrils, and fibrils. Beyond the polyQ domain, adjacent protein sequences influence the aggregation process. Specifically, the first 17 N-terminal amino acids (Nt17) directly preceding the polyQ domain promote the formation of α-helix-rich oligomers that represent intermediate species associated with fibrillization. Due to its propensity to form an amphipathic α-helix, Nt17 also facilitates lipid binding. Three lysine residues (K6, K9, and K15) within Nt17 can be SUMOylated, which modifies htt's accumulation and toxicity within cells in a variety of HD models. The impact of SUMOylation on htt aggregation and direct interaction with lipid membranes was investigated. SUMOylation of htt-exon1 inhibited fibril formation while promoting larger, amorphous aggregate species. These amorphous aggregates were SDS soluble but nonetheless exhibited levels of β-sheet structure similar to that of htt-exon1 fibrils. In addition, SUMOylation prevented htt binding, aggregation, and accumulation on model lipid bilayers comprised of total brain lipid extract. Collectively, these observations demonstrate that SUMOylation promotes a distinct htt aggregation pathway that may affect htt toxicity.
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Affiliation(s)
- Faezeh Sedighi
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States
| | - Adewale Adegbuyiro
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States
| | - Justin Legleiter
- The C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, Morgantown, West Virginia 26506, United States
- Rockefeller Neurosciences Institutes, West Virginia University, 1 Medical Center Drive, P.O. Box 9303, Morgantown, West Virginia 26505, United States
- Department of Neuroscience, West Virginia University, 1 Medical Center Drive, P.O. Box 9303, Morgantown, West Virginia 26505, United States
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31
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Arndt JR, Chaibva M, Beasley M, Karanji AK, Kondalaji SG, Khakinejad M, Sarver O, Legleiter J, Valentine SJ. Nucleation Inhibition of Huntingtin Protein (htt) by Polyproline PPII Helices: A Potential Interaction with the N-Terminal α-Helical Region of Htt. Biochemistry 2020; 59:436-449. [PMID: 31814404 PMCID: PMC7344267 DOI: 10.1021/acs.biochem.9b00689] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Huntington's disease is a genetic neurodegenerative disorder characterized by the formation of amyloid fibrils of the huntingtin protein (htt). The 17-residue N-terminal region of htt (Nt17) has been implicated in the formation of early phase oligomeric species, which may be neurotoxic. Because tertiary interactions with a downstream (C-terminal) polyproline (polyP) region of htt may disrupt the formation of oligomers, which are precursors to fibrillar species, the effect of co-incubation of a region of htt with a 10-residue polyP peptide on oligomerization and fibrillization has been examined by atomic force microscopy. From multiple, time-course experiments, morphological changes in oligomeric species are observed for the protein/peptide mixture and compared with the protein alone. Additionally, an overall decrease in fibril formation is observed for the heterogeneous mixture. To consider potential sites of interaction between the Nt17 region and polyP, mixtures containing Nt17 and polyP peptides have been examined by ion mobility spectrometry and gas-phase hydrogen-deuterium exchange coupled with mass spectrometry. These data combined with molecular dynamics simulations suggest that the C-terminal region of Nt17 may be a primary point of contact. One interpretation of the results is that polyP may possibly regulate Nt17 by inducing a random coil region in the C-terminal portion of Nt17, thus decreasing the propensity to form the reactive amphipathic α-helix. A separate interpretation is that the residues important for helix-helix interactions are blocked by polyP association.
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Affiliation(s)
- James R Arndt
- C. Eugene Bennett Department of Chemistry, West Virginia University, 100 Prospect Street, Morgantown, West Virginia 26506, United States
| | - Maxmore Chaibva
- C. Eugene Bennett Department of Chemistry, West Virginia University, 100 Prospect Street, Morgantown, West Virginia 26506, United States
| | - Maryssa Beasley
- C. Eugene Bennett Department of Chemistry, West Virginia University, 100 Prospect Street, Morgantown, West Virginia 26506, United States
| | - Ahmad Kiani Karanji
- C. Eugene Bennett Department of Chemistry, West Virginia University, 100 Prospect Street, Morgantown, West Virginia 26506, United States
| | - Samaneh Ghassabi Kondalaji
- C. Eugene Bennett Department of Chemistry, West Virginia University, 100 Prospect Street, Morgantown, West Virginia 26506, United States
| | - Mahdiar Khakinejad
- C. Eugene Bennett Department of Chemistry, West Virginia University, 100 Prospect Street, Morgantown, West Virginia 26506, United States
| | - Olivia Sarver
- C. Eugene Bennett Department of Chemistry, West Virginia University, 100 Prospect Street, Morgantown, West Virginia 26506, United States
| | - Justin Legleiter
- C. Eugene Bennett Department of Chemistry, West Virginia University, 100 Prospect Street, Morgantown, West Virginia 26506, United States
- WV Nano Safe Iniative, West Virginia University, Morgantown, West Virginia 26506, United States
- The Center for Neuroscience, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Stephen J Valentine
- C. Eugene Bennett Department of Chemistry, West Virginia University, 100 Prospect Street, Morgantown, West Virginia 26506, United States
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Optimizing intracellular antibodies (intrabodies/nanobodies) to treat neurodegenerative disorders. Neurobiol Dis 2020; 134:104619. [DOI: 10.1016/j.nbd.2019.104619] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 09/05/2019] [Accepted: 09/19/2019] [Indexed: 01/27/2023] Open
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Moldovean SN, Chiş V. Molecular Dynamics Simulations Applied to Structural and Dynamical Transitions of the Huntingtin Protein: A Review. ACS Chem Neurosci 2020; 11:105-120. [PMID: 31841621 DOI: 10.1021/acschemneuro.9b00561] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Over the recent years, Huntington's disease (HD) has become widely discussed in the scientific literature especially because at the mutant level there are several contradictions regarding the aggregation mechanism. The specific role of the physiological huntingtin protein remains unknown, due to the lack of characterization of its entire crystallographic structure, making the experimental and theoretical research even harder when taking into consideration its involvement in multiple biological functions and its high affinity for different interacting partners. Different types of models, containing fewer (not more than 35 Qs) polyglutamine residues for the WT structure and above 35 Qs for the mutants, were subjected to classical or advanced MD simulations to establish the proteins' structural stability by evaluating their conformational changes. Outside the polyQ tract, there are two other regions of interest (the N17 domain and the polyP rich domain) considered to be essential for the aggregation kinetics at the mutant level. The polymerization process is considered to be dependent on the polyQ length. As the polyQ tract's dimension increases, the structures present more β-sheet conformations. Contrarily, it is also considered that the aggregation stability is not necessarily dependent on the number of Qs, while the initial stage of the aggregation seed might play the decisive role. A general assumption regarding the polyP domain is that it might preserve the polyQ structures soluble by acting as an antagonist for β-sheet formation.
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Affiliation(s)
| | - Vasile Chiş
- Babeş-Bolyai University, Faculty of Physics, Kogălniceanu 1, RO-400084 Cluj-Napoca, Romania
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34
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Ultrasensitive quantitative measurement of huntingtin phosphorylation at residue S13. Biochem Biophys Res Commun 2020; 521:549-554. [DOI: 10.1016/j.bbrc.2019.09.097] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 09/22/2019] [Indexed: 11/21/2022]
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35
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Franich NR, Basso M, André EA, Ochaba J, Kumar A, Thein S, Fote G, Kachemov M, Lau AL, Yeung SY, Osmand A, Zeitlin SO, Ratan RR, Thompson LM, Steffan JS. Striatal Mutant Huntingtin Protein Levels Decline with Age in Homozygous Huntington's Disease Knock-In Mouse Models. J Huntingtons Dis 2019; 7:137-150. [PMID: 29843246 PMCID: PMC6002862 DOI: 10.3233/jhd-170274] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Background: Huntington’s disease (HD) is a progressive neurodegenerative disorder associated with aging, caused by an expanded polyglutamine (polyQ) repeat within the Huntingtin (HTT) protein. In HD, degeneration of the striatum and atrophy of the cortex are observed while cerebellum is less affected. Objective: To test the hypothesis that HTT protein levels decline with age, which together with HTT mutation could influence disease progression. Methods: Using whole brain cell lysates, a unique method of SDS-PAGE and western analysis was used to quantitate HTT protein, which resolves as a monomer and as a high molecular weight species that is modulated by the presence of transglutaminase 2. HTT levels were measured in striatum, cortex and cerebellum in congenic homozygous Q140 and HdhQ150 knock-in mice and WT littermate controls. Results: Mutant HTT in both homozygous knock-in HD mouse models and WT HTT in control striatal and cortical tissues significantly declined in a progressive manner over time. Levels of mutant HTT in HD cerebellum remained high during aging. Conclusions: A general decline in mutant HTT levels in striatum and cortex is observed that may contribute to disease progression in homozygous knock-in HD mouse models through reduction of HTT function. In cerebellum, sustained levels of mutant HTT with aging may be protective to this tissue which is less overtly affected in HD.
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Affiliation(s)
- Nicholas R Franich
- Department of Neurology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Manuela Basso
- Centre for Integrative Biology, University of Trento, Trento, Italy
| | - Emily A André
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Joseph Ochaba
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA, USA
| | - Amit Kumar
- Burke Medical Research Institute, White Plains, NY, USA.,Brain and Mind Research Institute, Weill Medical College of Cornell University, New York, NY, USA.,Department of Neurology, Weill Medical College of Cornell University, New York, NY, USA
| | - Soe Thein
- Department of Psychiatry and Human Behavior, University of California, Irvine, Irvine, CA, USA
| | - Gianna Fote
- Department of Psychiatry and Human Behavior, University of California, Irvine, Irvine, CA, USA
| | - Marketta Kachemov
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA, USA
| | - Alice L Lau
- Department of Psychiatry and Human Behavior, University of California, Irvine, Irvine, CA, USA
| | - Sylvia Y Yeung
- Department of Psychiatry and Human Behavior, University of California, Irvine, Irvine, CA, USA
| | - Alexander Osmand
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, USA
| | - Scott O Zeitlin
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Rajiv R Ratan
- Burke Medical Research Institute, White Plains, NY, USA.,Brain and Mind Research Institute, Weill Medical College of Cornell University, New York, NY, USA.,Department of Neurology, Weill Medical College of Cornell University, New York, NY, USA
| | - Leslie M Thompson
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA, USA.,Department of Psychiatry and Human Behavior, University of California, Irvine, Irvine, CA, USA.,Institute of Memory Impairments and Neurological Disorders, University of California, Irvine, Irvine, CA, USA
| | - Joan S Steffan
- Department of Psychiatry and Human Behavior, University of California, Irvine, Irvine, CA, USA.,Institute of Memory Impairments and Neurological Disorders, University of California, Irvine, Irvine, CA, USA
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36
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Maiuri T, Suart CE, Hung CLK, Graham KJ, Barba Bazan CA, Truant R. DNA Damage Repair in Huntington's Disease and Other Neurodegenerative Diseases. Neurotherapeutics 2019; 16:948-956. [PMID: 31364066 PMCID: PMC6985310 DOI: 10.1007/s13311-019-00768-7] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Recent genome-wide association studies of Huntington's disease (HD) primarily highlighted genes involved in DNA damage repair mechanisms as modifiers of age at onset and disease severity, consistent with evidence that more DNA repair genes are being implicated in late age-onset neurodegenerative diseases. This provides an exciting opportunity to advance therapeutic development in HD, as these pathways have already been under intense investigation in cancer research. Also emerging are the roles of other polyglutamine disease proteins in DNA damage repair mechanisms. A potential universal trigger of oxidative DNA damage shared in these late age-onset diseases is the increase of reactive oxygen species (ROS) in human aging, defining an age-related mechanism that has defied other hypotheses of neurodegeneration. We discuss the potential commonality of DNA damage repair pathways in HD and other neurodegenerative diseases. Potential targets for therapy that may prove beneficial across many of these diseases are also identified, defining nodes in the ataxia telangiectasia-mutated (ATM) complex, mismatch repair, and poly ADP-ribose polymerases (PARPs).
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Affiliation(s)
- T Maiuri
- Department of Biochemistry and Biomedical Sciences, McMaster University, HSC 4N54, 1200 Main Street West, Hamilton, Ontario, L8N3Z5, Canada
| | - C E Suart
- Department of Biochemistry and Biomedical Sciences, McMaster University, HSC 4N54, 1200 Main Street West, Hamilton, Ontario, L8N3Z5, Canada
| | - C L K Hung
- Department of Biochemistry and Biomedical Sciences, McMaster University, HSC 4N54, 1200 Main Street West, Hamilton, Ontario, L8N3Z5, Canada
| | - K J Graham
- Department of Biochemistry and Biomedical Sciences, McMaster University, HSC 4N54, 1200 Main Street West, Hamilton, Ontario, L8N3Z5, Canada
| | - C A Barba Bazan
- Department of Biochemistry and Biomedical Sciences, McMaster University, HSC 4N54, 1200 Main Street West, Hamilton, Ontario, L8N3Z5, Canada
| | - R Truant
- Department of Biochemistry and Biomedical Sciences, McMaster University, HSC 4N54, 1200 Main Street West, Hamilton, Ontario, L8N3Z5, Canada.
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Sap KA, Guler AT, Bezstarosti K, Bury AE, Juenemann K, Demmers JA, Reits EA. Global Proteome and Ubiquitinome Changes in the Soluble and Insoluble Fractions of Q175 Huntington Mice Brains. Mol Cell Proteomics 2019; 18:1705-1720. [PMID: 31138642 PMCID: PMC6731087 DOI: 10.1074/mcp.ra119.001486] [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] [Received: 04/05/2019] [Revised: 05/21/2019] [Indexed: 01/31/2023] Open
Abstract
Huntington's disease is caused by a polyglutamine repeat expansion in the huntingtin protein which affects the function and folding of the protein, and results in intracellular protein aggregates. Here, we examined whether this mutation leads to altered ubiquitination of huntingtin and other proteins in both soluble and insoluble fractions of brain lysates of the Q175 knock-in Huntington's disease mouse model and the Q20 wild-type mouse model. Ubiquitination sites are detected by identification of Gly-Gly (diGly) remnant motifs that remain on modified lysine residues after digestion. We identified K6, K9, K132, K804, and K837 as endogenous ubiquitination sites of soluble huntingtin, with wild-type huntingtin being mainly ubiquitinated at K132, K804, and K837. Mutant huntingtin protein levels were strongly reduced in the soluble fraction whereas K6 and K9 were mainly ubiquitinated. In the insoluble fraction increased levels of huntingtin K6 and K9 diGly sites were observed for mutant huntingtin as compared with wild type. Besides huntingtin, proteins with various roles, including membrane organization, transport, mRNA processing, gene transcription, translation, catabolic processes and oxidative phosphorylation, were differently expressed or ubiquitinated in wild-type and mutant huntingtin brain tissues. Correlating protein and diGly site fold changes in the soluble fraction revealed that diGly site abundances of most of the proteins were not related to protein fold changes, indicating that these proteins were differentially ubiquitinated in the Q175 mice. In contrast, both the fold change of the protein level and diGly site level were increased for several proteins in the insoluble fraction, including ubiquitin, ubiquilin-2, sequestosome-1/p62 and myo5a. Our data sheds light on putative novel proteins involved in different cellular processes as well as their ubiquitination status in Huntington's disease, which forms the basis for further mechanistic studies to understand the role of differential ubiquitination of huntingtin and ubiquitin-regulated processes in Huntington's disease.
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Affiliation(s)
- Karen A Sap
- ‡Department of Medical Biology, Amsterdam UMC, location AMC, Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands
| | - Arzu Tugce Guler
- ‡Department of Medical Biology, Amsterdam UMC, location AMC, Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands
| | - Karel Bezstarosti
- §Department of Biochemistry, Erasmus University Medical Center, Wytemaweg 80, 3015 CN Rotterdam, The Netherlands
| | - Aleksandra E Bury
- ‡Department of Medical Biology, Amsterdam UMC, location AMC, Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands
| | - Katrin Juenemann
- ¶Leibniz-Forschungsinstitut für Molekulare Pharmakologie im Forschungsverbund Berlin, Robert-Roessle-St. 10 13089 Berlin, Germany
| | - JeroenA A Demmers
- §Department of Biochemistry, Erasmus University Medical Center, Wytemaweg 80, 3015 CN Rotterdam, The Netherlands
| | - Eric A Reits
- ‡Department of Medical Biology, Amsterdam UMC, location AMC, Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands.
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Matlahov I, van der Wel PC. Conformational studies of pathogenic expanded polyglutamine protein deposits from Huntington's disease. Exp Biol Med (Maywood) 2019; 244:1584-1595. [PMID: 31203656 PMCID: PMC6920524 DOI: 10.1177/1535370219856620] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Huntington’s disease, like other neurodegenerative diseases, continues to lack an
effective cure. Current treatments that address early symptoms ultimately fail
Huntington’s disease patients and their families, with the disease typically
being fatal within 10–15 years from onset. Huntington’s disease is an inherited
disorder with motor and mental impairment, and is associated with the genetic
expansion of a CAG codon repeat encoding a polyglutamine-segment-containing
protein called huntingtin. These Huntington’s disease mutations cause misfolding
and aggregation of fragments of the mutant huntingtin protein, thereby likely
contributing to disease toxicity through a combination of gain-of-toxic-function
for the misfolded aggregates and a loss of function from sequestration of
huntingtin and other proteins. As with other amyloid diseases, the mutant
protein forms non-native fibrillar structures, which in Huntington’s disease are
found within patients’ neurons. The intracellular deposits are associated with
dysregulation of vital processes, and inter-neuronal transport of aggregates may
contribute to disease progression. However, a molecular understanding of these
aggregates and their detrimental effects has been frustrated by insufficient
structural data on the misfolded protein state. In this review, we examine
recent developments in the structural biology of polyglutamine-expanded
huntingtin fragments, and especially the contributions enabled by advances in
solid-state nuclear magnetic resonance spectroscopy. We summarize and discuss
our current structural understanding of the huntingtin deposits and how this
information furthers our understanding of the misfolding mechanism and disease
toxicity mechanisms.
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Affiliation(s)
- Irina Matlahov
- Department of Structural Biology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Patrick Ca van der Wel
- Department of Structural Biology, University of Pittsburgh, Pittsburgh, PA 15213, USA.,Zernike Institute for Advanced Materials, University of Groningen, Groningen 9747 AG, The Netherlands
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39
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Herrera F, Branco-Santos J, Outeiro T. Threonine 3 regulates Serine 13/16 phosphorylation in the huntingtin exon 1. ACTA ACUST UNITED AC 2019. [DOI: 10.19185/matters.201905000005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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40
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Probing initial transient oligomerization events facilitating Huntingtin fibril nucleation at atomic resolution by relaxation-based NMR. Proc Natl Acad Sci U S A 2019; 116:3562-3571. [PMID: 30808748 DOI: 10.1073/pnas.1821216116] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The N-terminal region of the huntingtin protein, encoded by exon-1, comprises an amphiphilic domain (httNT), a polyglutamine (Q n ) tract, and a proline-rich sequence. Polyglutamine expansion results in an aggregation-prone protein responsible for Huntington's disease. Here, we study the earliest events involved in oligomerization of a minimalistic construct, httNTQ7, which remains largely monomeric over a sufficiently long period of time to permit detailed quantitative NMR analysis of the kinetics and structure of sparsely populated [Formula: see text] oligomeric states, yet still eventually forms fibrils. Global fitting of concentration-dependent relaxation dispersion, transverse relaxation in the rotating frame, and exchange-induced chemical shift data reveals a bifurcated assembly mechanism in which the NMR observable monomeric species either self-associates to form a productive dimer (τex ∼ 30 μs, K diss ∼ 0.1 M) that goes on to form a tetramer ([Formula: see text] μs; K diss ∼ 22 μM), or exchanges with a "nonproductive" dimer that does not oligomerize further (τex ∼ 400 μs; K diss ∼ 0.3 M). The excited state backbone chemical shifts are indicative of a contiguous helix (residues 3-17) in the productive dimer/tetramer, with only partial helical character in the nonproductive dimer. A structural model of the productive dimer/tetramer was obtained by simulated annealing driven by intermolecular paramagnetic relaxation enhancement data. The tetramer comprises a D 2 symmetric dimer of dimers with largely hydrophobic packing between the helical subunits. The structural model, validated by EPR distance measurements, illuminates the role of the httNT domain in the earliest stages of prenucleation and oligomerization, before fibril formation.
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41
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Son S, Bowie LE, Maiuri T, Hung CLK, Desmond CR, Xia J, Truant R. High-mobility group box 1 links sensing of reactive oxygen species by huntingtin to its nuclear entry. J Biol Chem 2018; 294:1915-1923. [PMID: 30538129 DOI: 10.1074/jbc.ra117.001440] [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: 12/12/2017] [Revised: 12/04/2018] [Indexed: 11/06/2022] Open
Abstract
Huntington's disease (HD) is a neurodegenerative, age-onset disorder caused by a CAG DNA expansion in exon 1 of the HTT gene, resulting in a polyglutamine expansion in the huntingtin protein. Nuclear accumulation of mutant huntingtin is a hallmark of HD, resulting in elevated mutant huntingtin levels in cell nuclei. Huntingtin is normally retained at the endoplasmic reticulum via its N17 amphipathic α-helix domain but is released by oxidation of Met-8 during reactive oxygen species (ROS) stress. Huntingtin enters the nucleus via an importin β1- and 2-dependent proline-tyrosine nuclear localization signal (PY-NLS), which has a unique intervening sequence in huntingtin. Here, we have identified the high-mobility group box 1 (HMGB1) protein as an interactor of the intervening sequence within the PY-NLS. Nuclear levels of HMGB1 positively correlated with varying levels of nuclear huntingtin in both HD and normal human fibroblasts. We also found that HMGB1 interacts with the huntingtin N17 region and that this interaction is enhanced by the presence of ROS and phosphorylation of critical serine residues in the N17 region. We conclude that HMGB1 is a huntingtin N17/PY-NLS ROS-dependent interactor, and this protein bridging is essential for relaying ROS sensing by huntingtin to its nuclear entry during ROS stress. ROS may therefore be a critical age-onset stress that triggers nuclear accumulation of mutant huntington in Huntington's disease.
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Affiliation(s)
- Susie Son
- From the Department of Biochemistry and Biomedical Research, McMaster University, Hamilton, Ontario L8S 4L8, Canada
| | - Laura E Bowie
- From the Department of Biochemistry and Biomedical Research, McMaster University, Hamilton, Ontario L8S 4L8, Canada
| | - Tamara Maiuri
- From the Department of Biochemistry and Biomedical Research, McMaster University, Hamilton, Ontario L8S 4L8, Canada
| | - Claudia L K Hung
- From the Department of Biochemistry and Biomedical Research, McMaster University, Hamilton, Ontario L8S 4L8, Canada
| | - Carly R Desmond
- From the Department of Biochemistry and Biomedical Research, McMaster University, Hamilton, Ontario L8S 4L8, Canada
| | - Jianrun Xia
- From the Department of Biochemistry and Biomedical Research, McMaster University, Hamilton, Ontario L8S 4L8, Canada
| | - Ray Truant
- From the Department of Biochemistry and Biomedical Research, McMaster University, Hamilton, Ontario L8S 4L8, Canada
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Abstract
The 25 years since the identification of the gene responsible for Huntington disease (HD) have stood witness to profound discoveries about the nature of the disease and its pathogenesis. Despite this progress, however, the development of disease-modifying therapies has thus far been slow. Preclinical validation of the therapeutic potential of disrupted pathways in HD has led to the advancement of pharmacological agents, both novel and repurposed, for clinical evaluation. The most promising therapeutic approaches include huntingtin (HTT) lowering and modification as well as modulation of neuroinflammation and synaptic transmission. With clinical trials for many of these approaches imminent or currently ongoing, the coming years are promising not only for HD but also for more prevalent neurodegenerative disorders, such as Alzheimer and Parkinson disease, in which many of these pathways have been similarly implicated.
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DeGuire SM, Ruggeri FS, Fares MB, Chiki A, Cendrowska U, Dietler G, Lashuel HA. N-terminal Huntingtin (Htt) phosphorylation is a molecular switch regulating Htt aggregation, helical conformation, internalization, and nuclear targeting. J Biol Chem 2018; 293:18540-18558. [PMID: 30185623 PMCID: PMC6290154 DOI: 10.1074/jbc.ra118.004621] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 07/25/2018] [Indexed: 12/31/2022] Open
Abstract
Huntington's disease is a fatal neurodegenerative disorder resulting from a CAG repeat expansion in the first exon of the gene encoding the Huntingtin protein (Htt). Phosphorylation of this protein region (Httex1) has been shown to play important roles in regulating the structure, toxicity, and cellular properties of N-terminal fragments and full-length Htt. However, increasing evidence suggests that phosphomimetic substitutions in Htt result in inconsistent findings and do not reproduce all aspects of true phosphorylation. Here, we investigated the effects of bona fide phosphorylation at Ser-13 or Ser-16 on the structure, aggregation, membrane binding, and subcellular properties of the Httex1-Q18A variant and compared these effects with those of phosphomimetic substitutions. We show that phosphorylation at either Ser-13 and/or Ser-16 or phosphomimetic substitutions at both these residues inhibit the aggregation of mutant Httex1, but that only phosphorylation strongly disrupts the amphipathic α-helix of the N terminus and prompts the internalization and nuclear targeting of preformed Httex1 aggregates. In synthetic peptides, phosphorylation at Ser-13, Ser-16, or both residues strongly disrupted the amphipathic α-helix of the N-terminal 17 residues (Nt17) of Httex1 and Nt17 membrane binding. Experiments with peptides bearing different combinations of phosphorylation sites within Nt17 revealed a phosphorylation-dependent switch that regulates the Httex1 structure, involving cross-talk between phosphorylation at Thr-3 and Ser-13 or Ser-16. Our results provide crucial insights into the role of phosphorylation in regulating Httex1 structure and function, and underscore the critical importance of identifying the enzymes responsible for regulating Htt phosphorylation, and their potential as therapeutic targets for managing Huntington's disease.
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Affiliation(s)
- Sean M DeGuire
- From the Laboratory of Molecular and Chemical Biology of Neurodegeneration, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland and
| | - Francesco S Ruggeri
- the Laboratory of the Physics of Living Matter, Institute of Physics of Biological Systems, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Mohamed-Bilal Fares
- From the Laboratory of Molecular and Chemical Biology of Neurodegeneration, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland and
| | - Anass Chiki
- From the Laboratory of Molecular and Chemical Biology of Neurodegeneration, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland and
| | - Urszula Cendrowska
- the Laboratory of the Physics of Living Matter, Institute of Physics of Biological Systems, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Giovanni Dietler
- the Laboratory of the Physics of Living Matter, Institute of Physics of Biological Systems, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Hilal A Lashuel
- From the Laboratory of Molecular and Chemical Biology of Neurodegeneration, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland and
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44
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Reif A, Chiki A, Ricci J, Lashuel HA. Generation of Native, Untagged Huntingtin Exon1 Monomer and Fibrils Using a SUMO Fusion Strategy. J Vis Exp 2018. [PMID: 30010666 PMCID: PMC6102005 DOI: 10.3791/57506] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Huntington's Disease (HD) is an inherited fatal neurodegenerative disease caused by a CAG expansion (≥36) in the first exon of the HD gene, resulting in the expression of the Huntingtin protein (Htt) or N-terminal fragments thereof with an expanded polyglutamine (polyQ) stretch. The exon1 of the Huntingtin protein (Httex1) is the smallest Htt fragment that recapitulates many of the features of HD in cellular and animal models and is one of the most widely studied fragments of Htt. The small size of Httex1 makes it experimentally more amenable to biophysical characterization using standard and high-resolution techniques in comparison to longer fragments or full-length Htt. However, the high aggregation propensity of mutant Httex1 (mHttex1) with increased polyQ content (≥42) has made it difficult to develop efficient expression and purification systems to produce these proteins in sufficient quantities and make them accessible to scientists from different disciplines without the use of fusion proteins or other strategies that alter the native sequence of the protein. We present here a robust and optimized method for the production of milligram quantities of native, tag-free Httex1 based on the transient fusion of small ubiquitin related modifier (SUMO). The simplicity and efficiency of the strategy will eliminate the need to use non-native sequences of Httex1, thus making this protein more accessible to researchers and improving the reproducibility of experiments across different laboratories. We believe that these advances will also facilitate future studies aimed at elucidating the structure-function relationship of Htt as well as developing novel diagnostic tools and therapies to treat or slow the progression of HD.
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Affiliation(s)
- Andreas Reif
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Ecole Polytechnique Fédérale de Lausanne (EPFL)
| | - Anass Chiki
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Ecole Polytechnique Fédérale de Lausanne (EPFL)
| | - Jonathan Ricci
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Ecole Polytechnique Fédérale de Lausanne (EPFL)
| | - Hilal A Lashuel
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Ecole Polytechnique Fédérale de Lausanne (EPFL);
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45
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Sethi R, Tripathi N, Pallapati AR, Gaikar A, Bharatam PV, Roy I. Does N-terminal huntingtin function as a 'holdase' for inhibiting cellular protein aggregation? FEBS J 2018; 285:1791-1811. [PMID: 29630769 DOI: 10.1111/febs.14457] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 03/14/2018] [Accepted: 03/29/2018] [Indexed: 11/28/2022]
Abstract
Proteolytic cleavage of huntingtin gives rise to N-terminal fragments. While the role of truncated mutant huntingtin is described in Huntington's disease (HD) pathogenesis, the function of N-terminal wild-type protein is less studied. The yeast model of HD is generated by the presence of FLAG tag and absence of polyproline tract as flanking sequences of the elongated polyglutamine stretch. We show that the same sequence derived from wild-type huntingtin exon1 is able to inhibit the aggregation of proteins in vitro and in yeast cells. It is able to stabilize client proteins as varied as luciferase, α-synuclein, and p53 in a soluble but non-native state. This is somewhat similar to the 'holdase' function of small heat shock proteins and 'nonchaperone proteins' which are able to stabilize partially unfolded client proteins in a nonspecific manner, slowing down their aggregation. Mutagenesis studies show this property to be localized at the N17 domain preceding the polyglutamine tract. Distortion of this ordered segment, either by deletion of this segment or mutation of a single residue (L4A), leads to decreased stability and increased aggregation of client proteins. It is interesting to note that the helical conformation of the N17 domain is also essential for aggregation of the N-terminal mutant protein. Our results provide evidence for a novel function for the amphipathic helix derived from exon1 of wild-type huntingtin.
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Affiliation(s)
- Ratnika Sethi
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, Punjab, India
| | - Neha Tripathi
- Department of Pharmacoinformatics, National Institute of Pharmaceutical Education and Research, Punjab, India
| | - Anusha R Pallapati
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, Punjab, India
| | - Abhishek Gaikar
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, Punjab, India
| | - Prasad V Bharatam
- Department of Pharmacoinformatics, National Institute of Pharmaceutical Education and Research, Punjab, India.,Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research, Punjab, India
| | - Ipsita Roy
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research, Punjab, India
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Caterino M, Squillaro T, Montesarchio D, Giordano A, Giancola C, Melone MAB. Huntingtin protein: A new option for fixing the Huntington's disease countdown clock. Neuropharmacology 2018. [PMID: 29526547 DOI: 10.1016/j.neuropharm.2018.03.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Huntington's disease is a dreadful, incurable disorder. It springs from the autosomal dominant mutation in the first exon of the HTT gene, which encodes for the huntingtin protein (HTT) and results in progressive neurodegeneration. Thus far, all the attempted approaches to tackle the mutant HTT-induced toxicity causing this disease have failed. The mutant protein comes with the aberrantly expanded poly-glutamine tract. It is primarily to blame for the build-up of β-amyloid-like HTT aggregates, deleterious once broadened beyond the critical ∼35-37 repeats threshold. Recent experimental findings have provided valuable information on the molecular basis underlying this HTT-driven neurodegeneration. These findings indicate that the poly-glutamine siding regions and many post-translation modifications either abet or counter the poly-glutamine tract. This review provides an overall, up-to-date insight into HTT biophysics and structural biology, particularly discussing novel pharmacological options to specifically target the mutated protein and thus inhibit its functions and toxicity.
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Affiliation(s)
- Marco Caterino
- Department of Pharmacy, University of Napoli Federico II, Via D. Montesano 49, 80131, Napoli, Italy
| | - Tiziana Squillaro
- Department of Medical, Surgical, Neurological, Metabolic Sciences, and Aging, 2nd Division of Neurology, Center for Rare Diseases, University of Campania "Luigi Vanvitelli", Napoli, Italy; InterUniversity Center for Research in Neurosciences, University of Campania "Luigi Vanvitelli", Napoli, Italy
| | - Daniela Montesarchio
- InterUniversity Center for Research in Neurosciences, University of Campania "Luigi Vanvitelli", Napoli, Italy; Department of Chemical Sciences, University of Napoli Federico II, Via Cintia 21, 80126, Napoli, Italy
| | - Antonio Giordano
- Sbarro Institute for Cancer Research and Molecular Medicine, Department of Biology, Center for Biotechnology, College of Science and Technology, Temple University, Philadelphia, PA, USA; Department of Medicine, Surgery and Neuroscience University of Siena, Siena, Italy
| | - Concetta Giancola
- Department of Pharmacy, University of Napoli Federico II, Via D. Montesano 49, 80131, Napoli, Italy; InterUniversity Center for Research in Neurosciences, University of Campania "Luigi Vanvitelli", Napoli, Italy.
| | - Mariarosa A B Melone
- Department of Medical, Surgical, Neurological, Metabolic Sciences, and Aging, 2nd Division of Neurology, Center for Rare Diseases, University of Campania "Luigi Vanvitelli", Napoli, Italy; InterUniversity Center for Research in Neurosciences, University of Campania "Luigi Vanvitelli", Napoli, Italy; Sbarro Institute for Cancer Research and Molecular Medicine, Department of Biology, Center for Biotechnology, College of Science and Technology, Temple University, Philadelphia, PA, USA.
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Phosphorylation of huntingtin at residue T3 is decreased in Huntington's disease and modulates mutant huntingtin protein conformation. Proc Natl Acad Sci U S A 2017; 114:E10809-E10818. [PMID: 29162692 PMCID: PMC5740681 DOI: 10.1073/pnas.1705372114] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Posttranslational modifications can have profound effects on the biological and biophysical properties of proteins associated with misfolding and aggregation. However, their detection and quantification in clinical samples and an understanding of the mechanisms underlying the pathological properties of misfolding- and aggregation-prone proteins remain a challenge for diagnostics and therapeutics development. We have applied an ultrasensitive immunoassay platform to develop and validate a quantitative assay for detecting a posttranslational modification (phosphorylation at residue T3) of a protein associated with polyglutamine repeat expansion, namely Huntingtin, and characterized its presence in a variety of preclinical and clinical samples. We find that T3 phosphorylation is greatly reduced in samples from Huntington's disease models and in Huntington's disease patients, and we provide evidence that bona-fide T3 phosphorylation alters Huntingtin exon 1 protein conformation and aggregation properties. These findings have significant implications for both mechanisms of disease pathogenesis and the development of therapeutics and diagnostics for Huntington's disease.
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Warner JB, Ruff KM, Tan PS, Lemke EA, Pappu RV, Lashuel HA. Monomeric Huntingtin Exon 1 Has Similar Overall Structural Features for Wild-Type and Pathological Polyglutamine Lengths. J Am Chem Soc 2017; 139:14456-14469. [PMID: 28937758 PMCID: PMC5677759 DOI: 10.1021/jacs.7b06659] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Indexed: 12/22/2022]
Abstract
Huntington's disease is caused by expansion of a polyglutamine (polyQ) domain within exon 1 of the huntingtin gene (Httex1). The prevailing hypothesis is that the monomeric Httex1 protein undergoes sharp conformational changes as the polyQ length exceeds a threshold of 36-37 residues. Here, we test this hypothesis by combining novel semi-synthesis strategies with state-of-the-art single-molecule Förster resonance energy transfer measurements on biologically relevant, monomeric Httex1 proteins of five different polyQ lengths. Our results, integrated with atomistic simulations, negate the hypothesis of a sharp, polyQ length-dependent change in the structure of monomeric Httex1. Instead, they support a continuous global compaction with increasing polyQ length that derives from increased prominence of the globular polyQ domain. Importantly, we show that monomeric Httex1 adopts tadpole-like architectures for polyQ lengths below and above the pathological threshold. Our results suggest that higher order homotypic and/or heterotypic interactions within distinct sub-populations of neurons, which are inevitable at finite cellular concentrations, are likely to be the main source of sharp polyQ length dependencies of HD.
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Affiliation(s)
- John B. Warner
- Laboratory
of Molecular and Chemical Biology of Neurodegeneration, Brain Mind
Institute, Station 19, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Kiersten M. Ruff
- Department
of Biomedical Engineering and Center for Biological Systems Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Piau Siong Tan
- Structural
and Computational Biology Unit, Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), 69117 Heidelberg, Germany
| | - Edward A. Lemke
- Structural
and Computational Biology Unit, Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), 69117 Heidelberg, Germany
| | - Rohit V. Pappu
- Department
of Biomedical Engineering and Center for Biological Systems Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Hilal A. Lashuel
- Laboratory
of Molecular and Chemical Biology of Neurodegeneration, Brain Mind
Institute, Station 19, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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Arbez N, Ratovitski T, Roby E, Chighladze E, Stewart JC, Ren M, Wang X, Lavery DJ, Ross CA. Post-translational modifications clustering within proteolytic domains decrease mutant huntingtin toxicity. J Biol Chem 2017; 292:19238-19249. [PMID: 28972180 DOI: 10.1074/jbc.m117.782300] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Revised: 09/18/2017] [Indexed: 01/09/2023] Open
Abstract
Huntington's disease (HD) is caused in large part by a polyglutamine expansion within the huntingtin (Htt) protein. Post-translational modifications (PTMs) control and regulate many protein functions and cellular pathways, and PTMs of mutant Htt are likely important modulators of HD pathogenesis. Alterations of selected numbers of PTMs of Htt fragments have been shown to modulate Htt cellular localization and toxicity. In this study, we systematically introduced site-directed alterations in individual phosphorylation and acetylation sites in full-length Htt constructs. The effects of each of these PTM alteration constructs were tested on cell toxicity using our nuclear condensation assay and on mitochondrial viability by measuring mitochondrial potential and size. Using these functional assays in primary neurons, we identified several PTMs whose alteration can block neuronal toxicity and prevent potential loss and swelling of the mitochondria caused by mutant Htt. These PTMs included previously described sites such as serine 116 and newly found sites such as serine 2652 throughout the protein. We found that these functionally relevant sites are clustered in protease-sensitive domains throughout full-length Htt. These findings advance our understanding of the Htt PTM code and its role in HD pathogenesis. Because PTMs are catalyzed by enzymes, the toxicity-modulating Htt PTMs identified here may be promising therapeutic targets for managing HD.
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Affiliation(s)
- Nicolas Arbez
- From the Division of Neurobiology, Department of Psychiatry and Behavioral Sciences,
| | - Tamara Ratovitski
- From the Division of Neurobiology, Department of Psychiatry and Behavioral Sciences
| | - Elaine Roby
- From the Division of Neurobiology, Department of Psychiatry and Behavioral Sciences
| | - Ekaterine Chighladze
- From the Division of Neurobiology, Department of Psychiatry and Behavioral Sciences
| | - Jacqueline C Stewart
- From the Division of Neurobiology, Department of Psychiatry and Behavioral Sciences
| | - Mark Ren
- the Department of Neurobiology and Behavior, Cornell University, Ithaca, New York 14853, and
| | - Xiaofang Wang
- From the Division of Neurobiology, Department of Psychiatry and Behavioral Sciences
| | - Daniel J Lavery
- the CHDI Foundation/CHDI Management Inc., Princeton, New Jersey 08540
| | - Christopher A Ross
- From the Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, .,the Department of Neurology and Program in Cellular and Molecular Medicine, and.,the Departments of Pharmacology and Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287
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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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