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Ye S, Latham AP, Tang Y, Hsiung CH, Chen J, Luo F, Liu Y, Zhang B, Zhang X. Micropolarity governs the structural organization of biomolecular condensates. Nat Chem Biol 2024; 20:443-451. [PMID: 37973891 PMCID: PMC10978266 DOI: 10.1038/s41589-023-01477-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Accepted: 10/11/2023] [Indexed: 11/19/2023]
Abstract
Membraneless organelles within cells have unique microenvironments that play a critical role in their functions. However, how microenvironments of biomolecular condensates affect their structure and function remains unknown. In this study, we investigated the micropolarity and microviscosity of model biomolecular condensates by fluorescence lifetime imaging coupling with environmentally sensitive fluorophores. Using both in vitro and in cellulo systems, we demonstrated that sufficient micropolarity difference is key to forming multilayered condensates, where the shells present more polar microenvironments than the cores. Furthermore, micropolarity changes were shown to be accompanied by conversions of the layered structures. Decreased micropolarities of the granular components, accompanied by the increased micropolarities of the dense fibrillar components, result in the relocation of different nucleolus subcompartments in transcription-stalled conditions. Our results demonstrate the central role of the previously overlooked micropolarity in the regulation of structures and functions of membraneless organelles.
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Affiliation(s)
- Songtao Ye
- Department of Chemistry, Research Center for Industries of the Future, Westlake University, Hangzhou, China
- Institute of Natural Sciences, Westlake Institute for Advanced Study, Hangzhou, China
| | - Andrew P Latham
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Bioengineering and Therapeutic Sciences, Department of Pharmaceutical Chemistry, Quantitative Biosciences Institute, University of California, San Francisco, San Francisco, CA, USA
| | - Yuqi Tang
- Department of Chemistry, Research Center for Industries of the Future, Westlake University, Hangzhou, China
- Institute of Natural Sciences, Westlake Institute for Advanced Study, Hangzhou, China
| | - Chia-Heng Hsiung
- Department of Chemistry, Research Center for Industries of the Future, Westlake University, Hangzhou, China
- Institute of Natural Sciences, Westlake Institute for Advanced Study, Hangzhou, China
| | - Junlin Chen
- Department of Chemistry, Research Center for Industries of the Future, Westlake University, Hangzhou, China
- Institute of Natural Sciences, Westlake Institute for Advanced Study, Hangzhou, China
| | - Feng Luo
- Department of Chemistry, Research Center for Industries of the Future, Westlake University, Hangzhou, China
- Institute of Natural Sciences, Westlake Institute for Advanced Study, Hangzhou, China
| | - Yu Liu
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China
| | - Bin Zhang
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Xin Zhang
- Department of Chemistry, Research Center for Industries of the Future, Westlake University, Hangzhou, China.
- Institute of Natural Sciences, Westlake Institute for Advanced Study, Hangzhou, China.
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, China.
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2
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Arsiccio A, Liu X, Ganguly P, Buratto SK, Bowers MT, Shea JE. Effect of Cosolutes on the Aggregation of a Tau Fragment: A Combined Experimental and Simulation Approach. J Phys Chem B 2023; 127:4022-4031. [PMID: 37129599 DOI: 10.1021/acs.jpcb.3c00433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The intrinsically disordered protein Tau represents the main component of neurofibrillary tangles that are a hallmark of Alzheimer's disease. A small fragment of Tau, known as paired helical filament 6 (PHF6), is considered to be important for the formation of the β-structure core of the fibrils. Here we study the aggregation of this fragment in the presence of different cosolutes, including urea, TMAO, sucrose and 2-hydroxypropyl-β-cyclodextrin (2-HPβCD), using both experiments and molecular dynamics simulations. A novel implicit solvation approach (MIST - Model with Implicit Solvation Thermodynamics) is used, where an energetic contribution based on the concept of transfer free energies describes the effect of the cosolutes. The simulation predictions are compared to thioflavin-T and atomic force microscopy results, and the good agreement observed confirms the predictive ability of the computational approach herein proposed. Both simulations and experiments indicate that PHF6 aggregation is inhibited in the presence of urea and 2-HPβCD, while TMAO and sucrose stabilize associated conformations. The remarkable ability of HPβCD to inhibit aggregation represents an extremely promising result for future applications, especially considering the widespread use of this molecule as a drug carrier to the brain and as a solubilizer/excipient in pharmaceutical formulations.
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Affiliation(s)
- Andrea Arsiccio
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Xikun Liu
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Pritam Ganguly
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Steven K Buratto
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Michael T Bowers
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Joan-Emma Shea
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
- Department of Physics, University of California, Santa Barbara, California 93106, United States
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3
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Dey S, MacAinsh M, Zhou HX. Sequence-Dependent Backbone Dynamics of Intrinsically Disordered Proteins. J Chem Theory Comput 2022; 18:6310-6323. [PMID: 36084347 PMCID: PMC9561007 DOI: 10.1021/acs.jctc.2c00328] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
For intrinsically disordered proteins (IDPs), a pressing question is how sequence codes for function. Dynamics serves as a crucial link, reminiscent of the role of structure in sequence-function relations of structured proteins. To define general rules governing sequence-dependent backbone dynamics, we carried out long molecular dynamics simulations of eight IDPs. Blocks of residues exhibiting large amplitudes in slow dynamics are rigidified by local inter-residue interactions or secondary structures. A long region or an entire IDP can be slowed down by long-range contacts or secondary-structure packing. On the other hand, glycines promote fast dynamics and either demarcate rigid blocks or facilitate multiple modes of local and long-range inter-residue interactions. The sequence-dependent backbone dynamics endows IDPs with versatile response to binding partners, with some blocks recalcitrant while others readily adapting to intermolecular interactions.
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Affiliation(s)
- Souvik Dey
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Matthew MacAinsh
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Huan-Xiang Zhou
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL 60607, USA
- Department of Physics, University of Illinois at Chicago, Chicago, IL 60607, USA
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4
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Alipour M, Motavaf M, Abdolmaleki P, Zali A, Ashrafi F, Safari S, Hajipour-Verdom B. Structural Analysis and Conformational Dynamics of Short Helical Hyperphosphorylated Segments of Tau Protein (Sequence 254–290) in Alzheimer’s Disease: A Molecular Dynamics Simulation Study. Front Mol Biosci 2022; 9:884705. [PMID: 36003083 PMCID: PMC9393928 DOI: 10.3389/fmolb.2022.884705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Accepted: 06/09/2022] [Indexed: 11/21/2022] Open
Abstract
Alzheimer’s disease (AD) is a progressive neurodegenerative disorder whose early diagnosis leads to a chance for successful treatment and decreases the side effects. Hyperphosphorylation of tau proteins is a pathological hallmark of AD that causes it to lose its attachment ability to the microtubules. Alteration of tau structure due to its hyperphosphorylation is an exciting challenge regarding AD treatments. Here, we aimed to examine the structural alterations of short helical segments of tau protein with one to three phosphorylated sites by molecular dynamics simulation. Results indicated that the interaction of two similar segments with three phosphorylated sites (P-Ser262, 285, and 289) formed a compact and more stable structure than the one phosphorylated site complex (P-Ser262). Moreover, due to the high dynamics of the P-Ser262 complex, several structures were made with different conformational dynamics, but there was only one stable cluster of the P-Ser262, 285, and 289 complex during simulation. It seems that the P-Ser262, 285, and 289 complex plays an important role in the formation of paired helical filaments (PHFs) by forming a stable dimer. Generally, it is important to identify how structural features of segments in tau protein change when the phosphorylated sites increase from one to three sites and their effects on the formation of PHFs for drug design and diagnostic biomarkers.
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Affiliation(s)
- Mozhgan Alipour
- Functional Neurosurgery Research Center, Shohada Tajrish Comprehensive Neurosurgical Center of Excellence, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Department of Biophysics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran
| | - Mahsa Motavaf
- Functional Neurosurgery Research Center, Shohada Tajrish Comprehensive Neurosurgical Center of Excellence, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Parviz Abdolmaleki
- Department of Biophysics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran
| | - Alireza Zali
- Functional Neurosurgery Research Center, Shohada Tajrish Comprehensive Neurosurgical Center of Excellence, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Farzad Ashrafi
- Functional Neurosurgery Research Center, Shohada Tajrish Comprehensive Neurosurgical Center of Excellence, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Saeid Safari
- Functional Neurosurgery Research Center, Shohada Tajrish Comprehensive Neurosurgical Center of Excellence, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- *Correspondence: Saeid Safari, ; Behnam Hajipour-Verdom,
| | - Behnam Hajipour-Verdom
- Functional Neurosurgery Research Center, Shohada Tajrish Comprehensive Neurosurgical Center of Excellence, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Department of Biophysics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran
- *Correspondence: Saeid Safari, ; Behnam Hajipour-Verdom,
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5
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Dharmaraj GL, Arigo FD, Young KA, Martins R, Mancera RL, Bharadwaj P. Novel Amylin Analogues Reduce Amyloid-β Cross-Seeding Aggregation and Neurotoxicity. J Alzheimers Dis 2022; 87:373-390. [PMID: 35275530 DOI: 10.3233/jad-215339] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
BACKGROUND Type 2 diabetes related human islet amyloid polypeptide (hIAPP) plays a dual role in Alzheimer's disease (AD). hIAPP has neuroprotective effects in AD mouse models whereas, high hIAPP concentrations can promote co-aggregation with amyloid-β (Aβ) to promote neurodegeneration. In fact, both low and high plasma hIAPP concentration has been associated with AD. Therefore, non-aggregating hIAPP analogues have garnered interest as a treatment for AD. The aromatic amino acids F23 and I26 in hIAPP have been identified as the key residues involved in self-aggregation and Aβ cross-seeding. OBJECTIVE Three novel IAPP analogues with single and double alanine mutations (A1 = F23, A2 = I26, and A3 = F23 + I26) were assessed for their ability to aggregate, modulate Aβ oligomer formation, and alter neurotoxicity. METHODS A range of biophysical methods including Thioflavin-T, gel electrophoresis, photo-crosslinking, circular dichroism combined with cell viability assays were utilized to assess protein aggregation and toxicity. RESULTS All IAPP analogues showed significantly less self-aggregation than hIAPP. Co-aggregated Aβ 42-A2 and A3 also showed reduced aggregation compared to Aβ 42-hIAPP mixtures. Self- and co-oligomerized A1, A2, and A3 exhibited random coil conformations with reduced beta sheet content compared to hIAPP and Aβ 42-hIAPP aggregates. A1 was toxic at high concentrations compared to A2 and A3. However, co-aggregated Aβ 42-A1, A2, or A3 showed reduced neurotoxicity compared to Aβ 42, hIAPP, and Aβ 42-hIAPP aggregates. CONCLUSION These findings confirm that hIAPP analogues with non-aromatic residues at positions 23 and 26 have reduced self-aggregation and the ability to neutralize Aβ 42 toxicity. This warrants further characterization of their protective effects in pre-clinical AD models.
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Affiliation(s)
| | - Fraulein Denise Arigo
- Curtin Medical School, Curtin Health Innovation Research Institute, Curtin University, Perth WA, Australia
| | - Kimberly A Young
- Curtin Medical School, Curtin Health Innovation Research Institute, Curtin University, Perth WA, Australia
| | - Ralph Martins
- Centre of Excellence for Alzheimer's Disease Research and Care, School of Medical and Health Sciences, Edith Cowan University, Perth WA, Australia.,School of Biomedical Science, Macquarie University, Sydney, NSW, Australia
| | - Ricardo L Mancera
- Curtin Medical School, Curtin Health Innovation Research Institute, Curtin University, Perth WA, Australia
| | - Prashant Bharadwaj
- Centre of Excellence for Alzheimer's Disease Research and Care, School of Medical and Health Sciences, Edith Cowan University, Perth WA, Australia.,Curtin Medical School, Curtin Health Innovation Research Institute, Curtin University, Perth WA, Australia
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6
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Kitoka K, Skrabana R, Gasparik N, Hritz J, Jaudzems K. NMR Studies of Tau Protein in Tauopathies. Front Mol Biosci 2021; 8:761227. [PMID: 34859051 PMCID: PMC8632555 DOI: 10.3389/fmolb.2021.761227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 10/25/2021] [Indexed: 11/13/2022] Open
Abstract
Tauopathies, including Alzheimer's disease (AD), are the most troublesome of all age-related chronic conditions, as there are no well-established disease-modifying therapies for their prevention and treatment. Spatio-temporal distribution of tau protein pathology correlates with cognitive decline and severity of the disease, therefore, tau protein has become an appealing target for therapy. Current knowledge of the pathological effects and significance of specific species in the tau aggregation pathway is incomplete although more and more structural and mechanistic insights are being gained using biophysical techniques. Here, we review the application of NMR to structural studies of various tau forms that appear in its aggregation process, focusing on results obtained from solid-state NMR. Furthermore, we discuss implications from these studies and their prospective contribution to the development of new tauopathy therapies.
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Affiliation(s)
- Kristine Kitoka
- Laboratory of Physical Organic Chemistry, Latvian Institute of Organic Synthesis, Riga, Latvia
| | - Rostislav Skrabana
- Institute of Neuroimmunology, Slovak Academy of Sciences, Bratislava, Slovakia
- AXON Neuroscience R&D Services SE, Bratislava, Slovakia
| | - Norbert Gasparik
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
- Faculty of Science, National Centre for Biomolecular Research, Masaryk University, Brno, Czech Republic
| | - Jozef Hritz
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
- Department of Chemistry, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Kristaps Jaudzems
- Laboratory of Physical Organic Chemistry, Latvian Institute of Organic Synthesis, Riga, Latvia
- Faculty of Chemistry, University of Latvia, Riga, Latvia
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7
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Neurotoxicity of oligomers of phosphorylated Tau protein carrying tauopathy-associated mutation is inhibited by prion protein. Biochim Biophys Acta Mol Basis Dis 2021; 1867:166209. [PMID: 34246750 DOI: 10.1016/j.bbadis.2021.166209] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 06/24/2021] [Accepted: 07/06/2021] [Indexed: 01/03/2023]
Abstract
Tauopathies, including Alzheimer's disease (AD), are manifested by the deposition of well-characterized amyloid aggregates of Tau protein in the brain. However, it is rather unlikely that these aggregates constitute the major form of Tau responsible for neurodegenerative changes. Currently, it is postulated that the intermediates termed as soluble oligomers, assembled on the amyloidogenic pathway, are the most neurotoxic form of Tau. However, Tau oligomers reported so far represent a population of poorly characterized, heterogeneous and unstable assemblies. In this study, to obtain the oligomers, we employed the aggregation-prone K18 fragment of Tau protein with deletion of Lys280 (K18Δ280) linked to a hereditary tauopathy. We have described a new procedure of inducing aggregation of mutated K18 which leads either to the formation of nontoxic amyloid fibrils or neurotoxic globular oligomers, depending on its phosphorylation status. We demonstrate that PKA-phosphorylated K18Δ280 oligomers are toxic to hippocampal neurons, which is manifested by loss of dendritic spines and neurites, and impairment of cell-membrane integrity leading to cell death. We also show that N1, the soluble N-terminal fragment of prion protein (PrP), protects neurons from the oligomers-induced cytotoxicity. Our findings support the hypothesis on the neurotoxicity of Tau oligomers and neuroprotective role of PrP-derived fragments in AD and other tauopathies. These observations could be useful in the development of therapeutic strategies for these diseases.
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8
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Nguyen PH, Ramamoorthy A, Sahoo BR, Zheng J, Faller P, Straub JE, Dominguez L, Shea JE, Dokholyan NV, De Simone A, Ma B, Nussinov R, Najafi S, Ngo ST, Loquet A, Chiricotto M, Ganguly P, McCarty J, Li MS, Hall C, Wang Y, Miller Y, Melchionna S, Habenstein B, Timr S, Chen J, Hnath B, Strodel B, Kayed R, Lesné S, Wei G, Sterpone F, Doig AJ, Derreumaux P. Amyloid Oligomers: A Joint Experimental/Computational Perspective on Alzheimer's Disease, Parkinson's Disease, Type II Diabetes, and Amyotrophic Lateral Sclerosis. Chem Rev 2021; 121:2545-2647. [PMID: 33543942 PMCID: PMC8836097 DOI: 10.1021/acs.chemrev.0c01122] [Citation(s) in RCA: 368] [Impact Index Per Article: 122.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Protein misfolding and aggregation is observed in many amyloidogenic diseases affecting either the central nervous system or a variety of peripheral tissues. Structural and dynamic characterization of all species along the pathways from monomers to fibrils is challenging by experimental and computational means because they involve intrinsically disordered proteins in most diseases. Yet understanding how amyloid species become toxic is the challenge in developing a treatment for these diseases. Here we review what computer, in vitro, in vivo, and pharmacological experiments tell us about the accumulation and deposition of the oligomers of the (Aβ, tau), α-synuclein, IAPP, and superoxide dismutase 1 proteins, which have been the mainstream concept underlying Alzheimer's disease (AD), Parkinson's disease (PD), type II diabetes (T2D), and amyotrophic lateral sclerosis (ALS) research, respectively, for many years.
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Affiliation(s)
- Phuong H Nguyen
- CNRS, UPR9080, Université de Paris, Laboratory of Theoretical Biochemistry, IBPC, Fondation Edmond de Rothschild, PSL Research University, Paris 75005, France
| | - Ayyalusamy Ramamoorthy
- Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Bikash R Sahoo
- Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Jie Zheng
- Department of Chemical & Biomolecular Engineering, The University of Akron, Akron, Ohio 44325, United States
| | - Peter Faller
- Institut de Chimie, UMR 7177, CNRS-Université de Strasbourg, 4 rue Blaise Pascal, 67000 Strasbourg, France
| | - John E Straub
- Department of Chemistry, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, United States
| | - Laura Dominguez
- Facultad de Química, Departamento de Fisicoquímica, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico
| | - Joan-Emma Shea
- Department of Chemistry and Biochemistry, and Department of Physics, University of California, Santa Barbara, California 93106, United States
| | - Nikolay V Dokholyan
- Department of Pharmacology and Biochemistry & Molecular Biology, Penn State University College of Medicine, Hershey, Pennsylvania 17033, United States
- Department of Chemistry, and Biomedical Engineering, Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Alfonso De Simone
- Department of Life Sciences, Imperial College London, London SW7 2AZ, U.K
- Molecular Biology, University of Naples Federico II, Naples 80138, Italy
| | - Buyong Ma
- Basic Science Program, Leidos Biomedical Research, Inc., Cancer and Inflammation Program, National Cancer Institute, Frederick, Maryland 21702, United States
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China
| | - Ruth Nussinov
- Basic Science Program, Leidos Biomedical Research, Inc., Cancer and Inflammation Program, National Cancer Institute, Frederick, Maryland 21702, United States
- Sackler Institute of Molecular Medicine, Department of Human Genetics and Molecular Medicine Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Saeed Najafi
- Department of Chemistry and Biochemistry, and Department of Physics, University of California, Santa Barbara, California 93106, United States
| | - Son Tung Ngo
- Laboratory of Theoretical and Computational Biophysics & Faculty of Applied Sciences, Ton Duc Thang University, 33000 Ho Chi Minh City, Vietnam
| | - Antoine Loquet
- Institute of Chemistry & Biology of Membranes & Nanoobjects, (UMR5248 CBMN), CNRS, Université Bordeaux, Institut Européen de Chimie et Biologie, 33600 Pessac, France
| | - Mara Chiricotto
- Department of Chemical Engineering and Analytical Science, University of Manchester, Manchester M13 9PL, U.K
| | - Pritam Ganguly
- Department of Chemistry and Biochemistry, and Department of Physics, University of California, Santa Barbara, California 93106, United States
| | - James McCarty
- Chemistry Department, Western Washington University, Bellingham, Washington 98225, United States
| | - Mai Suan Li
- Institute for Computational Science and Technology, SBI Building, Quang Trung Software City, Tan Chanh Hiep Ward, District 12, Ho Chi Minh City 700000, Vietnam
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
| | - Carol Hall
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695-7905, United States
| | - Yiming Wang
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695-7905, United States
| | - Yifat Miller
- Department of Chemistry and The Ilse Katz Institute for Nanoscale Science & Technology, Ben-Gurion University of the Negev, Be'er Sheva 84105, Israel
| | | | - Birgit Habenstein
- Institute of Chemistry & Biology of Membranes & Nanoobjects, (UMR5248 CBMN), CNRS, Université Bordeaux, Institut Européen de Chimie et Biologie, 33600 Pessac, France
| | - Stepan Timr
- CNRS, UPR9080, Université de Paris, Laboratory of Theoretical Biochemistry, IBPC, Fondation Edmond de Rothschild, PSL Research University, Paris 75005, France
| | - Jiaxing Chen
- Department of Pharmacology and Biochemistry & Molecular Biology, Penn State University College of Medicine, Hershey, Pennsylvania 17033, United States
| | - Brianna Hnath
- Department of Pharmacology and Biochemistry & Molecular Biology, Penn State University College of Medicine, Hershey, Pennsylvania 17033, United States
| | - Birgit Strodel
- Institute of Complex Systems: Structural Biochemistry (ICS-6), Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Rakez Kayed
- Mitchell Center for Neurodegenerative Diseases, and Departments of Neurology, Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas 77555, United States
| | - Sylvain Lesné
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Guanghong Wei
- Department of Physics, State Key Laboratory of Surface Physics, and Key Laboratory for Computational Physical Science, Multiscale Research Institute of Complex Systems, Fudan University, Shanghai 200438, China
| | - Fabio Sterpone
- CNRS, UPR9080, Université de Paris, Laboratory of Theoretical Biochemistry, IBPC, Fondation Edmond de Rothschild, PSL Research University, Paris 75005, France
| | - Andrew J Doig
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, U.K
| | - Philippe Derreumaux
- CNRS, UPR9080, Université de Paris, Laboratory of Theoretical Biochemistry, IBPC, Fondation Edmond de Rothschild, PSL Research University, Paris 75005, France
- Laboratory of Theoretical Chemistry, Ton Duc Thang University, 33000 Ho Chi Minh City, Vietnam
- Faculty of Pharmacy, Ton Duc Thang University, 33000 Ho Chi Minh City, Vietnam
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9
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Lin Y, Fichou Y, Longhini AP, Llanes LC, Yin P, Bazan GC, Kosik KS, Han S. Liquid-Liquid Phase Separation of Tau Driven by Hydrophobic Interaction Facilitates Fibrillization of Tau. J Mol Biol 2021; 433:166731. [PMID: 33279579 PMCID: PMC7855949 DOI: 10.1016/j.jmb.2020.166731] [Citation(s) in RCA: 64] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 11/29/2020] [Accepted: 11/30/2020] [Indexed: 11/17/2022]
Abstract
Amyloid aggregation of tau protein is implicated in neurodegenerative diseases, yet its facilitating factors are poorly understood. Recently, tau has been shown to undergo liquid liquid phase separation (LLPS) both in vivo and in vitro. LLPS was shown to facilitate tau amyloid aggregation in certain cases, while being independent of aggregation in other cases. It is therefore important to understand the differentiating properties that resolve this apparent conflict. We report on a model system of hydrophobically driven LLPS induced by high salt concentration (LLPS-HS), and compare it to electrostatically driven LLPS represented by tau-RNA/heparin complex coacervation (LLPS-ED). We show that LLPS-HS promotes tau protein dehydration, undergoes maturation and directly leads to canonical tau fibrils, while LLPS-ED is reversible, remains hydrated and does not promote amyloid aggregation. We show that the nature of the interaction driving tau condensation is a differentiating factor between aggregation-prone and aggregation-independent LLPS.
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Affiliation(s)
- Yanxian Lin
- Biomolecular Science and Engineering, University of California, Santa Barbara, CA 93106, United States
| | - Yann Fichou
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106, United States
| | - Andrew P Longhini
- Molecular, Cell and Developmental Biology, University of California, Santa Barbara, CA 93106, United States
| | - Luana C Llanes
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106, United States; Center for Polymers and Organic Solids, University of California, Santa Barbara, CA 93106, United States
| | - Pengyi Yin
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106, United States
| | - Guillermo C Bazan
- Departments of Chemistry and Chemical Engineering, National University of Singapore, 117543, Singapore
| | - Kenneth S Kosik
- Molecular, Cell and Developmental Biology, University of California, Santa Barbara, CA 93106, United States; Neuroscience Research Institute, University of California, Santa Barbara, CA 93106, United States
| | - Songi Han
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106, United States; Department of Chemical Engineering, University of California, Santa Barbara, CA 93106, United States.
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10
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Arya S, Ganguly P, Arsiccio A, Claud SL, Trapp B, Schonfeld GE, Liu X, Lazar Cantrell K, Shea JE, Bowers MT. Terminal Capping of an Amyloidogenic Tau Fragment Modulates Its Fibrillation Propensity. J Phys Chem B 2020; 124:8772-8783. [PMID: 32816481 DOI: 10.1021/acs.jpcb.0c05768] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Aberrant protein folding leading to the formation of characteristic cross-β-sheet-rich amyloid structures is well known for its association with a variety of debilitating human diseases. Often, depending upon amino acid composition, only a small segment of a large protein participates in amyloid formation and is in fact capable of self-assembling into amyloid, independent of the rest of the protein. Therefore, such peptide fragments serve as useful model systems for understanding the process of amyloid formation. An important factor that has often been overlooked while using peptides to mimic full-length protein is the charge on the termini of these peptides. Here, we show the influence of terminal charges on the aggregation of an amyloidogenic peptide from microtubule-associated protein Tau, implicated in Alzheimer's disease and tauopathies. We found that modification of terminal charges by capping the peptide at one or both of the termini drastically modulates the fibrillation of the hexapeptide sequence paired helical filament 6 (PHF6) from repeat 3 of Tau, both with and without heparin. Without heparin, the PHF6 peptide capped at both termini and PHF6 capped only at the N-terminus self-assembled to form amyloid fibrils. With heparin, all capping variants of PHF6, except for PHF6 with both termini free, formed typical amyloid fibrils. However, the rate and extent of aggregation both with and without heparin as well as the morphology of aggregates were found to be highly dependent on the terminal charges. Our molecular dynamics simulations on PHF6 capping variants corroborated our experiments and provided critical insights into the mechanism of PHF6 self-assembly. Overall, our results emphasize the importance of terminal modifications in fibrillation of small peptide fragments and provide significant insights into the aggregation of a small Tau fragment, which is considered essential for Tau filament assembly.
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Affiliation(s)
- Shruti Arya
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
| | - Pritam Ganguly
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
| | - Andrea Arsiccio
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
| | - Sarah L Claud
- Department of Chemistry, Westmont College, Santa Barbara, California 93108, United States
| | - Benjamin Trapp
- Neon Therapeutics, Cambridge, Massachusetts 02139, United States
| | - Grace E Schonfeld
- Department of Chemistry, Westmont College, Santa Barbara, California 93108, United States
| | - Xikun Liu
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
| | - Kristi Lazar Cantrell
- Department of Chemistry, Westmont College, Santa Barbara, California 93108, United States
| | - Joan-Emma Shea
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
| | - Michael T Bowers
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
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11
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Zubčić K, Hof PR, Šimić G, Jazvinšćak Jembrek M. The Role of Copper in Tau-Related Pathology in Alzheimer's Disease. Front Mol Neurosci 2020; 13:572308. [PMID: 33071757 PMCID: PMC7533614 DOI: 10.3389/fnmol.2020.572308] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Accepted: 08/19/2020] [Indexed: 12/12/2022] Open
Abstract
All tauopathies, including Alzheimer's disease (AD), are characterized by the intracellular accumulation of abnormal forms of tau protein in neurons and glial cells, which negatively affect microtubule stability. Under physiological conditions, tubulin-associated unit (Tau) protein is intrinsically disordered, almost without secondary structure, and is not prone to aggregation. In AD, it assembles, and forms paired helical filaments (PHFs) that further build-up neurofibrillary tangles (NFTs). Aggregates are composed of hyperphosphorylated tau protein that is more prone to aggregation. The pathology of AD is also linked to disturbed copper homeostasis, which promotes oxidative stress (OS). Copper imbalance is widely observed in AD patients. Deregulated copper ions may initiate and exacerbate tau hyperphosphorylation and formation of β-sheet-rich tau fibrils that ultimately contribute to synaptic failure, neuronal death, and cognitive decline observed in AD patients. The present review summarizes factors affecting the process of tau aggregation, conformational changes of small peptide sequences in the microtubule-binding domain required for these motifs to act as seeding sites in aggregation, and the role of copper in OS induction, tau hyperphosphorylation and tau assembly. A better understanding of the various factors that affect tau aggregation under OS conditions may reveal new targets and novel pharmacological approaches for the therapy of AD.
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Affiliation(s)
- Klara Zubčić
- Laboratory for Developmental Neuropathology, Department for Neuroscience, Croatian Institute for Brain Research, University of Zagreb Medical School, Zagreb, Croatia
| | - Patrick R Hof
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, United States.,Ronald M. Loeb Center for Alzheimer's Disease, Icahn School of Medicine at Mount Sinai, New York, NY, United States.,Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Goran Šimić
- Laboratory for Developmental Neuropathology, Department for Neuroscience, Croatian Institute for Brain Research, University of Zagreb Medical School, Zagreb, Croatia
| | - Maja Jazvinšćak Jembrek
- Laboratory for Protein Dynamics, Division of Molecular Medicine, Ruđer Bošković Institute, Zagreb, Croatia.,Department of Psychology, Catholic University of Croatia, Zagreb, Croatia
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12
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Tau and Alpha Synuclein Synergistic Effect in Neurodegenerative Diseases: When the Periphery Is the Core. Int J Mol Sci 2020; 21:ijms21145030. [PMID: 32708732 PMCID: PMC7404325 DOI: 10.3390/ijms21145030] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 07/13/2020] [Accepted: 07/14/2020] [Indexed: 02/08/2023] Open
Abstract
In neuronal cells, tau is a microtubule-associated protein placed in axons and alpha synuclein is enriched at presynaptic terminals. They display a propensity to form pathologic aggregates, which are considered the underlying cause of Alzheimer's and Parkinson's diseases. Their functional impairment induces loss of axonal transport, synaptic and mitochondrial disarray, leading to a "dying back" pattern of degeneration, which starts at the periphery of cells. In addition, pathologic spreading of alpha-synuclein from the peripheral nervous system to the brain through anatomical connectivity has been demonstrated for Parkinson's disease. Thus, examination of the extent and types of tau and alpha-synuclein in peripheral tissues and their relation to brain neurodegenerative diseases is of relevance since it may provide insights into patterns of protein aggregation and neurodegeneration. Moreover, peripheral nervous tissues are easily accessible in-vivo and can play a relevant role in the early diagnosis of these conditions. Up-to-date investigations of tau species in peripheral tissues are scant and have mainly been restricted to rodents, whereas, more evidence is available on alpha synuclein in peripheral tissues. Here we aim to review the literature on the functional role of tau and alpha synuclein in physiological conditions and disease at the axonal level, their distribution in peripheral tissues, and discuss possible commonalities/diversities as well as their interaction in proteinopathies.
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13
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Lin Y, Fichou Y, Zeng Z, Hu NY, Han S. Electrostatically Driven Complex Coacervation and Amyloid Aggregation of Tau Are Independent Processes with Overlapping Conditions. ACS Chem Neurosci 2020; 11:615-627. [PMID: 31971365 DOI: 10.1021/acschemneuro.9b00627] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Amyloid aggregation of the microtubule binding protein tau is a hallmark of many neurodegenerative diseases. Recently, tau has been found to undergo liquid-liquid phase separation (LLPS) by an electrostatically driven complex coacervation (CC) mechanism near physiological conditions. Although LLPS and aggregation have been shown to simultaneously occur under certain common conditions, it is unclear whether LLPS promotes aggregation of tau, or whether they are two independent processes. In this study, we address this question by combining multiple biochemical and biophysical assays in vitro. We investigate the impacts of LLPS-CC on cofactor-induced tau aggregation by evaluating the conformation of tau, kinetics of aggregation, and fibril quantity. We showed that none of these properties are influenced directly by LLPS-CC and that LLPS-CC and cofactor-induced aggregation of tau merely occur under overlapping conditions of enhanced intermolecular interactions and localization but are two independent processes. We furthermore showed that tau LLPS can be driven by nonelectrostatic interaction using high-salt concentrations. Under these conditions, LLPS strongly correlated with increased aggregation propensity. Whether LLPS of tau formed under different conditions or of different constituents may actively promote aggregation of tau remains an open question, but this study shows that the readily accessible electrostatically driven condensation of tau into LLPS in and of itself is not sufficient to promote aggregation.
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Affiliation(s)
- Yanxian Lin
- Biomolecular Science and Engineering, University of California, Santa Barbara, California 93106, United States
| | - Yann Fichou
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Zhikai Zeng
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Nicole Y. Hu
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
| | - Songi Han
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
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14
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15
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Amir Mishan M, Rezaei Kanavi M, Shahpasand K, Ahmadieh H. Pathogenic Tau Protein Species: Promising Therapeutic Targets for Ocular Neurodegenerative Diseases. J Ophthalmic Vis Res 2019; 14:491-505. [PMID: 31875105 PMCID: PMC6825701 DOI: 10.18502/jovr.v14i4.5459] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 06/11/2019] [Indexed: 12/13/2022] Open
Abstract
Tau is a microtubule-associated protein, which is highly expressed in the central nervous system as well as ocular neurons and stabilizes microtubule structure. It is a phospho-protein being moderately phosphorylated under physiological conditions but its abnormal hyperphosphorylation or some post-phosphorylation modifications would result in a pathogenic condition, microtubule dissociation, and aggregation. The aggregates can induce neuroinflammation and trigger some pathogenic cascades, leading to neurodegeneration. Taking these together, targeting pathogenic tau employing tau immunotherapy may be a promising therapeutic strategy in fighting with cerebral and ocular neurodegenerative disorders.
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Affiliation(s)
- Mohammad Amir Mishan
- Ocular Tissue Engineering Research Center, Student Research Committee, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mozhgan Rezaei Kanavi
- Ocular Tissue Engineering Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Koorosh Shahpasand
- Department of Brain and Cognitive Sciences, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, ACECR, Tehran, Iran
| | - Hamid Ahmadieh
- Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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16
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Lin Y, McCarty J, Rauch JN, Delaney KT, Kosik KS, Fredrickson GH, Shea JE, Han S. Narrow equilibrium window for complex coacervation of tau and RNA under cellular conditions. eLife 2019; 8:e42571. [PMID: 30950394 PMCID: PMC6450672 DOI: 10.7554/elife.42571] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 03/06/2019] [Indexed: 12/28/2022] Open
Abstract
The mechanism that leads to liquid-liquid phase separation (LLPS) of the tau protein, whose pathological aggregation is implicated in neurodegenerative disorders, is not well understood. Establishing a phase diagram that delineates the boundaries of phase co-existence is key to understanding whether LLPS is an equilibrium or intermediate state. We demonstrate that tau and RNA reversibly form complex coacervates. While the equilibrium phase diagram can be fit to an analytical theory, a more advanced model is investigated through field theoretic simulations (FTS) that provided direct insight into the thermodynamic driving forces of tau LLPS. Together, experiment and simulation reveal that tau-RNA LLPS is stable within a narrow equilibrium window near physiological conditions over experimentally tunable parameters including temperature, salt and tau concentrations, and is entropy-driven. Guided by our phase diagram, we show that tau can be driven toward LLPS under live cell coculturing conditions with rationally chosen experimental parameters.
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Affiliation(s)
- Yanxian Lin
- Biomolecular Science and EngineeringUniversity of California Santa BarbaraSanta BarbaraUnited States
| | - James McCarty
- Department of Chemistry and BiochemistryUniversity of California Santa BarbaraSanta BarbaraUnited States
| | - Jennifer N Rauch
- Department of Molecular, Cellular and Developmental BiologyUniversity of California Santa BarbaraSanta BarbaraUnited States
- Neuroscience Research InstituteUniversity of California Santa BarbaraSanta BarbaraUnited States
| | - Kris T Delaney
- Materials Research LaboratoryUniversity of California Santa BarbaraSanta BarbaraUnited States
| | - Kenneth S Kosik
- Department of Molecular, Cellular and Developmental BiologyUniversity of California Santa BarbaraSanta BarbaraUnited States
- Neuroscience Research InstituteUniversity of California Santa BarbaraSanta BarbaraUnited States
| | - Glenn H Fredrickson
- Materials Research LaboratoryUniversity of California Santa BarbaraSanta BarbaraUnited States
- Department of Chemical EngineeringUniversity of California Santa BarbaraSanta BarbaraUnited States
| | - Joan-Emma Shea
- Department of Chemistry and BiochemistryUniversity of California Santa BarbaraSanta BarbaraUnited States
- Department of PhysicsUniversity of California Santa BarbaraSanta BarbaraUnited States
| | - Songi Han
- Department of Chemistry and BiochemistryUniversity of California Santa BarbaraSanta BarbaraUnited States
- Department of Chemical EngineeringUniversity of California Santa BarbaraSanta BarbaraUnited States
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17
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Abstract
The accumulation of tau filaments in neurons is a pathological hallmark of various neurodegenerative diseases, including Alzheimer's disease. However, it is not the filamentous aggregates themselves, but non-filamentous tau species, tau oligomer, that is thought to be the culprit in tau-mediated neurodegeneration. The definition of and methodology for isolating tau oligomers vary among researchers. Here we describe how tau oligomers are identified, summarize the differences of tau oligomers among research groups, and discuss their hypothesized functions.
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18
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Tau Protein Squired by Molecular Chaperones During Alzheimer’s Disease. J Mol Neurosci 2018; 66:356-368. [DOI: 10.1007/s12031-018-1174-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 09/14/2018] [Indexed: 01/19/2023]
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19
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Jangholi A, Ashrafi-Kooshk MR, Arab SS, Karima S, Poorebrahim M, Ghadami SA, Moosavi-Movahedi AA, Khodarahmi R. Can any “non-specific charge modification within microtubule binding domains of Tau” be a prerequisite of the protein amyloid aggregation? An in vitro study on the 1N4R isoform. Int J Biol Macromol 2018; 109:188-204. [DOI: 10.1016/j.ijbiomac.2017.12.071] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 12/07/2017] [Accepted: 12/11/2017] [Indexed: 01/26/2023]
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20
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Cornejo A, Aguilar Sandoval F, Caballero L, Machuca L, Muñoz P, Caballero J, Perry G, Ardiles A, Areche C, Melo F. Rosmarinic acid prevents fibrillization and diminishes vibrational modes associated to β sheet in tau protein linked to Alzheimer's disease. J Enzyme Inhib Med Chem 2017; 32:945-953. [PMID: 28701064 PMCID: PMC6009890 DOI: 10.1080/14756366.2017.1347783] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Revised: 06/13/2017] [Accepted: 06/23/2017] [Indexed: 01/22/2023] Open
Abstract
Alzheimer's disease is a common tauopathy where fibril formation and aggregates are the hallmark of the disease. Efforts targeting amyloid-β plaques have succeeded to remove plaques but failed in clinical trials to improve cognition; thus, the current therapeutic strategy is at preventing tau aggregation. Here, we demonstrated that four phenolic diterpenoids and rosmarinic acid inhibit fibrillization. Since, rosmarinic acid was the most active compound, we observe morphological changes in atomic force microscopy images after treatment. Hence, rosmarinic acid leads to a decrease in amide regions I and III, indicating that rosmarinic acid prevents β-sheet assembly. Molecular docking study inside the steric zipper model of the hexapeptide 306VQIVYK311 involved in fibrillization and β sheet formation, suggests that rosmarinic acid binds to the steric zipper with similar chemical interactions with respect to those observed for orange G, a known pharmacofore for amyloid.
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Affiliation(s)
- Alberto Cornejo
- Escuela de Tecnología Médica, Facultad de Medicina, Universidad Andres Bello, Santiago, Chile
| | - Felipe Aguilar Sandoval
- Departamento de Física, Facultad de Ciencias Fisicas y Matematicas, Universidad de Chile, Santiago, Chile
| | - Leonardo Caballero
- Departamento de Física, Facultad de Ciencias Fisicas y Matematicas, Universidad de Chile, Santiago, Chile
| | - Luis Machuca
- Escuela de Tecnología Médica, Facultad de Medicina, Universidad Andres Bello, Santiago, Chile
| | - Patricio Muñoz
- Escuela de Tecnología Médica, Facultad de Medicina, Universidad Andres Bello, Santiago, Chile
| | - Julio Caballero
- Centro bioinformático y modelamiento molecular, Facultad de Ingeniería, Universidad de Talca, Talca, Chile
| | - George Perry
- College of Sciences, University of Texas at San Antonio, San Antonio, TX, USA
| | - Alejandro Ardiles
- Departamento de Química, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Carlos Areche
- Departamento de Química, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Francisco Melo
- Departamento de Física, Facultad de Ciencias Fisicas y Matematicas, Universidad de Chile, Santiago, Chile
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21
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Discovery and characterization of stable and toxic Tau/phospholipid oligomeric complexes. Nat Commun 2017; 8:1678. [PMID: 29162800 PMCID: PMC5698329 DOI: 10.1038/s41467-017-01575-4] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 09/29/2017] [Indexed: 11/13/2022] Open
Abstract
The microtubule-associated protein Tau plays a central role in the pathogenesis of Alzheimer’s disease. Although Tau interaction with membranes is thought to affect some of its physiological functions and its aggregation properties, the sequence determinants and the structural and functional consequences of such interactions remain poorly understood. Here, we report that the interaction of Tau with vesicles results in the formation of highly stable protein/phospholipid complexes. These complexes are toxic to primary hippocampal cultures and are detected by MC-1, an antibody recognizing pathological Tau conformations. The core of these complexes is comprised of the PHF6* and PHF6 hexapeptide motifs, the latter in a β-strand conformation. Studies using Tau-derived peptides enabled the design of mutants that disrupt Tau interactions with phospholipids without interfering with its ability to form fibrils, thus providing powerful tools for uncoupling these processes and investigating the role of membrane interactions in regulating Tau function, aggregation and toxicity. The Alzheimer protein Tau interacts with biological membranes, but the role of these interactions in regulating Tau function in health and disease remains unexplored. Here, the authors report on the discovery and characterization of neurotoxic oligomeric protein/phospholipid complexes.
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22
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Mathis CA, Lopresti BJ, Ikonomovic MD, Klunk WE. Small-molecule PET Tracers for Imaging Proteinopathies. Semin Nucl Med 2017; 47:553-575. [PMID: 28826526 DOI: 10.1053/j.semnuclmed.2017.06.003] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
In this chapter, we provide a review of the challenges and advances in developing successful PET imaging agents for 3 major types of aggregated amyloid proteins: amyloid-beta (Aβ), tau, and alpha-synuclein (α-syn). These 3 amyloids are involved in the pathogenesis of a variety of neurodegenerative diseases, referred to as proteinopathies or proteopathies, that include Alzheimer disease, Lewy body dementias, multiple system atrophy, and frontotemporal dementias, among others. In the Introduction section, we briefly discuss the history of amyloid in neurodegenerative diseases and describe why progress in developing effective imaging agents has been hampered by the failure of crystallography to provide definitive ligand-protein interactions for rational radioligand design efforts. Instead, the field has relied on largely serendipitous, trial-and-error methods to achieve useful and specific PET amyloid imaging tracers for Aβ, tau, and α-syn deposits. Because many of the proteopathies involve more than 1 amyloid protein, it is important to develop selective PET tracers for the different amyloids to help assess the relative contribution of each to total amyloid burden. We use Pittsburgh compound B to illustrate some of the critical steps in developing a potent and selective Aβ PET imaging agent. Other selective Aβ and tau PET imaging compounds have followed similar pathways in their developmental processes. Success for selective α-syn PET imaging agents has not been realized yet, but work is ongoing in multiple laboratories throughout the world. In the tau sections, we provide background regarding 3-repeat (3R) and 4-repeat (4R) tau proteins and how they can affect the binding of tau radioligands in different tauopathies. We review the ongoing efforts to assess the properties of tau ligands, which are useful in 3R, 4R, or combined 3R-4R tauopathies. Finally, we describe in the α-syn sections recent attempts to develop selective tracers to image α-synucleinopathies.
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Affiliation(s)
- Chester A Mathis
- Department of Radiology, University of Pittsburgh School of Medicine, Pittsburgh, PA.
| | - Brian J Lopresti
- Department of Radiology, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Milos D Ikonomovic
- Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - William E Klunk
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA
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23
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Guo T, Noble W, Hanger DP. Roles of tau protein in health and disease. Acta Neuropathol 2017; 133:665-704. [PMID: 28386764 PMCID: PMC5390006 DOI: 10.1007/s00401-017-1707-9] [Citation(s) in RCA: 559] [Impact Index Per Article: 79.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 03/26/2017] [Accepted: 03/26/2017] [Indexed: 01/18/2023]
Abstract
Tau is well established as a microtubule-associated protein in neurons. However, under pathological conditions, aberrant assembly of tau into insoluble aggregates is accompanied by synaptic dysfunction and neural cell death in a range of neurodegenerative disorders, collectively referred to as tauopathies. Recent advances in our understanding of the multiple functions and different locations of tau inside and outside neurons have revealed novel insights into its importance in a diverse range of molecular pathways including cell signalling, synaptic plasticity, and regulation of genomic stability. The present review describes the physiological and pathophysiological properties of tau and how these relate to its distribution and functions in neurons. We highlight the post-translational modifications of tau, which are pivotal in defining and modulating tau localisation and its roles in health and disease. We include discussion of other pathologically relevant changes in tau, including mutation and aggregation, and how these aspects impinge on the propensity of tau to propagate, and potentially drive neuronal loss, in diseased brain. Finally, we describe the cascade of pathological events that may be driven by tau dysfunction, including impaired axonal transport, alterations in synapse and mitochondrial function, activation of the unfolded protein response and defective protein degradation. It is important to fully understand the range of neuronal functions attributed to tau, since this will provide vital information on its involvement in the development and pathogenesis of disease. Such knowledge will enable determination of which critical molecular pathways should be targeted by potential therapeutic agents developed for the treatment of tauopathies.
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Affiliation(s)
- Tong Guo
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, SE5 9NU, UK
| | - Wendy Noble
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, SE5 9NU, UK
| | - Diane P Hanger
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, SE5 9NU, UK.
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24
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Akoury E, Mukrasch MD, Biernat J, Tepper K, Ozenne V, Mandelkow E, Blackledge M, Zweckstetter M. Remodeling of the conformational ensemble of the repeat domain of tau by an aggregation enhancer. Protein Sci 2016; 25:1010-20. [PMID: 26940799 DOI: 10.1002/pro.2911] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Revised: 01/27/2016] [Accepted: 02/26/2016] [Indexed: 11/09/2022]
Abstract
Misfolding of the microtubule-associated protein Tau is a hallmark of Alzheimer disease and several other neurodegenerative disorders. Because of the dynamic nature of the Tau protein, little is known about the changes in Tau structure that occur during misfolding. Here we studied the structural consequences upon binding of the repeat domain of Tau, which plays a key role in pathogenic aggregation, to an aggregation enhancer. By combining NMR experiments with molecular simulations we show that binding of the aggregation enhancer polyglutamic acid remodels the conformational ensemble of Tau. Our study thus provides insight into an early event during misfolding of Tau.
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Affiliation(s)
- Elias Akoury
- Department for NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, 37077, Germany
| | - Marco D Mukrasch
- Department for NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, 37077, Germany
| | - Jacek Biernat
- German Center for Neurodegenerative Diseases (DZNE), Bonn, 53175, Germany
| | - Katharina Tepper
- German Center for Neurodegenerative Diseases (DZNE), Bonn, 53175, Germany
| | - Valery Ozenne
- Institut de Biologie Structurale (IBS), CEA, CNRS, University Grenoble Alpes, Grenoble, 38044, France
| | - Eckhard Mandelkow
- German Center for Neurodegenerative Diseases (DZNE), Bonn, 53175, Germany.,CAESAR Research Center, Ludwig-Erhard-Allee 2, Bonn, 53175, Germany, and MPI for Metabolism Resesearch, Hamburg Outstation, c/o DESY, 22607 Hamburg, Germany
| | - Martin Blackledge
- Institut de Biologie Structurale (IBS), CEA, CNRS, University Grenoble Alpes, Grenoble, 38044, France
| | - Markus Zweckstetter
- Department for NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, 37077, Germany.,German Center for Neurodegenerative Diseases (DZNE), Göttingen, 37075, Germany.,Department of Neurology, University Medical Center Göttingen, Göttingen, 37073, Germany
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25
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Sabbagh JJ, Dickey CA. The Metamorphic Nature of the Tau Protein: Dynamic Flexibility Comes at a Cost. Front Neurosci 2016; 10:3. [PMID: 26834532 PMCID: PMC4720746 DOI: 10.3389/fnins.2016.00003] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2015] [Accepted: 01/07/2016] [Indexed: 12/28/2022] Open
Abstract
Accumulation of the microtubule associated protein tau occurs in several neurodegenerative diseases including Alzheimer's disease (AD). The tau protein is intrinsically disordered, giving it unique structural properties that can be dynamically altered by post-translational modifications such as phosphorylation and cleavage. Over the last decade, technological advances in nuclear magnetic resonance (NMR) spectroscopy and structural modeling have permitted more in-depth insights into the nature of tau. These studies have helped elucidate how metamorphism of tau makes it ideally suited for dynamic microtubule regulation, but how it also facilitates tau self-assembly, oligomerization, and neurotoxicity. This review will focus on how the distinct structure of tau governs its function, accumulation, and toxicity as well as how other cellular factors such as molecular chaperones control these processes.
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Affiliation(s)
- Jonathan J Sabbagh
- Department of Molecular Medicine, Byrd Alzheimer's Research Institute, University of South Florida Tampa, FL, USA
| | - Chad A Dickey
- Department of Molecular Medicine, Byrd Alzheimer's Research Institute, University of South Florida Tampa, FL, USA
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Protein structural and surface water rearrangement constitute major events in the earliest aggregation stages of tau. Proc Natl Acad Sci U S A 2015; 113:E127-36. [PMID: 26712030 DOI: 10.1073/pnas.1504415113] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Protein aggregation plays a critical role in the pathogenesis of neurodegenerative diseases, and the mechanism of its progression is poorly understood. Here, we examine the structural and dynamic characteristics of transiently evolving protein aggregates under ambient conditions by directly probing protein surface water diffusivity, local protein segment dynamics, and interprotein packing as a function of aggregation time, along the third repeat domain and C terminus of Δtau187 spanning residues 255-441 of the longest isoform of human tau. These measurements were achieved with a set of highly sensitive magnetic resonance tools that rely on site-specific electron spin labeling of Δtau187. Within minutes of initiated aggregation, the majority of Δtau187 that is initially homogeneously hydrated undergoes structural transformations to form partially structured aggregation intermediates. This is reflected in the dispersion of surface water dynamics that is distinct around the third repeat domain, found to be embedded in an intertau interface, from that of the solvent-exposed C terminus. Over the course of hours and in a rate-limiting process, a majority of these aggregation intermediates proceed to convert into stable β-sheet structured species and maintain their stacking order without exchanging their subunits. The population of β-sheet structured species is >5% within 5 min of aggregation and gradually grows to 50-70% within the early stages of fibril formation, while they mostly anneal block-wisely to form elongated fibrils. Our findings suggest that the formation of dynamic aggregation intermediates constitutes a major event occurring in the earliest stages of tau aggregation that precedes, and likely facilitates, fibril formation and growth.
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27
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Shimojo M, Higuchi M, Suhara T, Sahara N. Imaging Multimodalities for Dissecting Alzheimer's Disease: Advanced Technologies of Positron Emission Tomography and Fluorescence Imaging. Front Neurosci 2015; 9:482. [PMID: 26733795 PMCID: PMC4686595 DOI: 10.3389/fnins.2015.00482] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 12/01/2015] [Indexed: 01/24/2023] Open
Abstract
The rapid progress in advanced imaging technologies has expanded our toolbox for monitoring a variety of biological aspects in living subjects including human. In vivo radiological imaging using small chemical tracers, such as with positron emission tomography, represents an especially vital breakthrough in the efforts to improve our understanding of the complicated cascade of neurodegenerative disorders including Alzheimer's disease (AD), and it has provided the most reliable visible biomarkers for enabling clinical diagnosis. At the same time, in combination with genetically modified animal model systems, the most recent innovation of fluorescence imaging is helping establish diverse applications in basic neuroscience research, from single-molecule analysis to animal behavior manipulation, suggesting the potential utility of fluorescence technology for dissecting the detailed molecular-based consequence of AD pathophysiology. In this review, our primary focus is on a current update of PET radiotracers and fluorescence indicators beneficial for understanding the AD cascade, and discussion of the utility and pitfalls of those imaging modalities for future translational research applications. We will also highlight current cutting-edge genetic approaches and discuss how to integrate individual technologies for further potential innovations.
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Affiliation(s)
- Masafumi Shimojo
- Molecular Neuroimaging Program, Molecular Imaging Center, National Institute of Radiological Sciences Chiba, Japan
| | - Makoto Higuchi
- Molecular Neuroimaging Program, Molecular Imaging Center, National Institute of Radiological Sciences Chiba, Japan
| | - Tetsuya Suhara
- Molecular Neuroimaging Program, Molecular Imaging Center, National Institute of Radiological Sciences Chiba, Japan
| | - Naruhiko Sahara
- Molecular Neuroimaging Program, Molecular Imaging Center, National Institute of Radiological Sciences Chiba, Japan
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28
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Janowska MK, Wu KP, Baum J. Unveiling transient protein-protein interactions that modulate inhibition of alpha-synuclein aggregation by beta-synuclein, a pre-synaptic protein that co-localizes with alpha-synuclein. Sci Rep 2015; 5:15164. [PMID: 26477939 PMCID: PMC4609965 DOI: 10.1038/srep15164] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 09/11/2015] [Indexed: 01/18/2023] Open
Abstract
Pathology in Parkinson’s disease is linked to self-association of α-Synuclein (αS) into pathogenic oligomeric species and highly ordered amyloid fibrils. Developing effective therapeutic strategies against this debilitating disease is critical and βS, a pre-synaptic protein that co-localizes with αS, can act as an inhibitor of αS assembly. Despite the potential importance of βS as an inhibitor of αS, the nature, location and specificity of the molecular interactions between these two proteins is unknown. Here we use NMR paramagnetic relaxation enhancement experiments, to demonstrate that βS interacts directly with αS in a transient dimer complex with high specificity and weak affinity. Inhibition of αS by βS arises from transient αS/βS heterodimer species that exist primarily in head- to- tail configurations while αS aggregation arises from a more heterogeneous and weaker range of transient interactions that include both head-to-head and head-to-tail configurations. Our results highlight that intrinsically disordered proteins can interact directly with one another at low affinity and that the transient interactions that drive inhibition versus aggregation are distinct by virtue of their plasticity and specificity.
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Affiliation(s)
- Maria K Janowska
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854
| | - Kuen-Phon Wu
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854
| | - Jean Baum
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854
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29
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Lee M, Baek I, Choi H, Kim JI, Na S. Effects of lysine residues on structural characteristics and stability of tau proteins. Biochem Biophys Res Commun 2015; 466:486-92. [DOI: 10.1016/j.bbrc.2015.09.056] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2015] [Accepted: 09/11/2015] [Indexed: 11/26/2022]
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30
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Oktaviani NA, Risør MW, Lee YH, Megens RP, de Jong DH, Otten R, Scheek RM, Enghild JJ, Nielsen NC, Ikegami T, Mulder FAA. Optimized co-solute paramagnetic relaxation enhancement for the rapid NMR analysis of a highly fibrillogenic peptide. JOURNAL OF BIOMOLECULAR NMR 2015; 62:129-42. [PMID: 25820763 DOI: 10.1007/s10858-015-9925-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2014] [Accepted: 03/20/2015] [Indexed: 05/21/2023]
Abstract
Co-solute paramagnetic relaxation enhancement (PRE) is an attractive way to speed up data acquisition in NMR spectroscopy by shortening the T 1 relaxation time of the nucleus of interest and thus the necessary recycle delay. Here, we present the rationale to utilize high-spin iron(III) as the optimal transition metal for this purpose and characterize the properties of its neutral chelate form Fe(DO3A) as a suitable PRE agent. Fe(DO3A) effectively reduces the T 1 values across the entire sequence of the intrinsically disordered protein α-synuclein with negligible impact on line width. The agent is better suited than currently used alternatives, shows no specific interaction with the polypeptide chain and, due to its high relaxivity, is effective at low concentrations and in 'proton-less' NMR experiments. By using Fe(DO3A) we were able to complete the backbone resonance assignment of a highly fibrillogenic peptide from α1-antitrypsin by acquiring the necessary suite of multidimensional NMR datasets in 3 h.
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Affiliation(s)
- Nur Alia Oktaviani
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, The Netherlands
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31
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Atsmon-Raz Y, Miller Y. Insight into Atomic Resolution of the Cross-Seeding between Tau/Mutated Tau and Amyloid-β in Neurodegenerative Diseases. Isr J Chem 2015. [DOI: 10.1002/ijch.201400162] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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32
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Ganguly P, Do TD, Larini L, LaPointe NE, Sercel AJ, Shade MF, Feinstein SC, Bowers MT, Shea JE. Tau assembly: the dominant role of PHF6 (VQIVYK) in microtubule binding region repeat R3. J Phys Chem B 2015; 119:4582-93. [PMID: 25775228 PMCID: PMC4428543 DOI: 10.1021/acs.jpcb.5b00175] [Citation(s) in RCA: 124] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Self-aggregation of the microtubule-binding protein Tau reduces its functionality and is tightly associated with Tau-related diseases, termed tauopathies. Tau aggregation is also strongly associated with two nucleating six-residue segments, namely PHF6 (VQIVYK) and PHF6* (VQIINK). In this paper, using experiments and computational modeling, we study the self-assembly of individual and binary mixtures of Tau fragments containing PHF6* (R2/wt; (273)GKVQIINKKLDL(284)) and PHF6 (R3/wt; (306)VQIVYKPVDLSK(317)) and a mutant R2/ΔK280 associated with a neurodegenerative tauopathy. The initial stage of aggregation is probed by ion-mobility mass spectrometry, the kinetics of aggregation monitored with Thioflavin T assays, and the morphology of aggregates visualized by transmission electron microscopy. Insights into the structure of early aggregates and the factors stabilizing the aggregates are obtained from replica exchange molecular dynamics simulations. Our data suggest that R3/wt has a much stronger aggregation propensity than either R2/wt or R2/ΔK280. Heterodimers containing R3/wt are less stable than R3/wt homodimers but much more stable than homodimers of R2/wt and R2/ΔK280, suggesting a possible role of PHF6*-PHF6 interactions in initiating the aggregation of full-length Tau. Lastly, R2/ΔK280 binds more strongly to R3/wt than R2/wt, suggesting a possible mechanism for a pathological loss of normal Tau function.
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Affiliation(s)
- Pritam Ganguly
- Department of Chemistry and Biochemistry, University of California at Santa Barbara, Santa Barbara, California, 93106, USA
| | - Thanh D. Do
- Department of Chemistry and Biochemistry, University of California at Santa Barbara, Santa Barbara, California, 93106, USA
| | - Luca Larini
- Department of Chemistry and Biochemistry, University of California at Santa Barbara, Santa Barbara, California, 93106, USA
| | - Nichole E. LaPointe
- Neuroscience Research Institute and Department of Molecular, Cellular and Developmental Biology, University of California at Santa Barbara, Santa Barbara, California, 93106, USA
| | - Alexander J. Sercel
- Neuroscience Research Institute and Department of Molecular, Cellular and Developmental Biology, University of California at Santa Barbara, Santa Barbara, California, 93106, USA
| | - Madeleine F. Shade
- Neuroscience Research Institute and Department of Molecular, Cellular and Developmental Biology, University of California at Santa Barbara, Santa Barbara, California, 93106, USA
| | - Stuart C. Feinstein
- Neuroscience Research Institute and Department of Molecular, Cellular and Developmental Biology, University of California at Santa Barbara, Santa Barbara, California, 93106, USA
| | - Michael T. Bowers
- Department of Chemistry and Biochemistry, University of California at Santa Barbara, Santa Barbara, California, 93106, USA
| | - Joan-Emma Shea
- Department of Chemistry and Biochemistry, University of California at Santa Barbara, Santa Barbara, California, 93106, USA
- Department of Physics, University of California at Santa Barbara, Santa Barbara, California, 93106, USA
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33
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Abstract
Myriad biological processes proceed through states that defy characterization by conventional atomic-resolution structural biological methods. The invisibility of these 'dark' states can arise from their transient nature, low equilibrium population, large molecular weight, and/or heterogeneity. Although they are invisible, these dark states underlie a range of processes, acting as encounter complexes between proteins and as intermediates in protein folding and aggregation. New methods have made these states accessible to high-resolution analysis by nuclear magnetic resonance (NMR) spectroscopy, as long as the dark state is in dynamic equilibrium with an NMR-visible species. These methods - paramagnetic NMR, relaxation dispersion, saturation transfer, lifetime line broadening, and hydrogen exchange - allow the exploration of otherwise invisible states in exchange with a visible species over a range of timescales, each taking advantage of some unique property of the dark state to amplify its effect on a particular NMR observable. In this review, we introduce these methods and explore two specific techniques - paramagnetic relaxation enhancement and dark state exchange saturation transfer - in greater detail.
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Affiliation(s)
- Nicholas J. Anthis
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520, USA
| | - G. Marius Clore
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520, USA
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34
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Grüning CSR, Mirecka EA, Klein AN, Mandelkow E, Willbold D, Marino SF, Stoldt M, Hoyer W. Alternative conformations of the Tau repeat domain in complex with an engineered binding protein. J Biol Chem 2014; 289:23209-23218. [PMID: 24966331 DOI: 10.1074/jbc.m114.560920] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The aggregation of Tau into paired helical filaments is involved in the pathogenesis of several neurodegenerative diseases, including Alzheimer disease. The aggregation reaction is characterized by conformational conversion of the repeat domain, which partially adopts a cross-β-structure in the resulting amyloid-like fibrils. Here, we report the selection and characterization of an engineered binding protein, β-wrapin TP4, targeting the Tau repeat domain. TP4 was obtained by phage display using the four-repeat Tau construct K18ΔK280 as a target. TP4 binds K18ΔK280 as well as the longest isoform of human Tau, hTau40, with nanomolar affinity. NMR spectroscopy identified two alternative TP4-binding sites in the four-repeat domain, with each including two hexapeptide motifs with high β-sheet propensity. Both binding sites contain the aggregation-determining PHF6 hexapeptide within repeat 3. In addition, one binding site includes the PHF6* hexapeptide within repeat 2, whereas the other includes the corresponding hexapeptide Tau(337-342) within repeat 4, denoted PHF6**. Comparison of TP4-binding with Tau aggregation reveals that the same regions of Tau are involved in both processes. TP4 inhibits Tau aggregation at substoichiometric concentration, demonstrating that it interferes with aggregation nucleation. This study provides residue-level insight into the interaction of Tau with an aggregation inhibitor and highlights the structural flexibility of Tau.
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Affiliation(s)
- Clara S R Grüning
- Institute of Physical Biology, Heinrich-Heine-Universität, 40204 Düsseldorf, Germany
| | - Ewa A Mirecka
- Institute of Physical Biology, Heinrich-Heine-Universität, 40204 Düsseldorf, Germany
| | - Antonia N Klein
- Institute of Structural Biochemistry (ICS-6), Research Centre Jülich, 52425 Jülich, Germany
| | - Eckhard Mandelkow
- German Center for Neurodegenerative Diseases (DZNE), 53175 Bonn, Germany, and; Center of Advanced European Studies And Research (CAESAR), 53175 Bonn, Germany
| | - Dieter Willbold
- Institute of Physical Biology, Heinrich-Heine-Universität, 40204 Düsseldorf, Germany,; Institute of Structural Biochemistry (ICS-6), Research Centre Jülich, 52425 Jülich, Germany
| | - Stephen F Marino
- Institute of Physical Biology, Heinrich-Heine-Universität, 40204 Düsseldorf, Germany
| | - Matthias Stoldt
- Institute of Physical Biology, Heinrich-Heine-Universität, 40204 Düsseldorf, Germany,; Institute of Structural Biochemistry (ICS-6), Research Centre Jülich, 52425 Jülich, Germany
| | - Wolfgang Hoyer
- Institute of Physical Biology, Heinrich-Heine-Universität, 40204 Düsseldorf, Germany,; Institute of Structural Biochemistry (ICS-6), Research Centre Jülich, 52425 Jülich, Germany,.
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35
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Barré P, Eliezer D. Structural transitions in tau k18 on micelle binding suggest a hierarchy in the efficacy of individual microtubule-binding repeats in filament nucleation. Protein Sci 2013; 22:1037-48. [PMID: 23740819 DOI: 10.1002/pro.2290] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Revised: 05/21/2013] [Accepted: 05/22/2013] [Indexed: 12/31/2022]
Abstract
The protein tau is found in an aggregated filamentous state in the intraneuronal paired helical filament deposits characteristic of Alzheimer's disease and other related dementias and mutations in tau protein and mRNA cause frontotemproal dementia. Tau isoforms include a microtubule-binding domain containing either three or four imperfect tandem microtubule binding repeats that also form the core of tau filaments and contain hexapaptide motifs that are critical for tau aggregation. The tau microtubule-binding domain can also engage in direct interactions with detergents, fatty acids, or membranes, which can greatly facilitate tau aggregation and may also mediate some tau functions. Here, we show that the alternatively spliced second microtubule-binding repeat exhibits significantly different structural characteristics compared with the other three repeats in the context of the intact repeat domain. Most notably, the PHF6* hexapeptide motif located at the N-terminus of repeat 2 has a lower propensity to form strand-like structure than the corresponding PHF6 motif in repeat 3, and unlike PHF6 converts to partially helical structure in the micelle-bound state. Interestingly, the behavior of the Module-B motif, located at the beginning of repeat 4, resembles that of PHF6* rather than PHF6. Our observations, combined with previous results showing that PHF6* and Module-B are both less effective than PHF6 in nucleating tau aggregation, suggest a hierarchy in the efficacy of these motifs in nucleating tau aggregation that originates in differences in their intrinsic propensities for extended strand-like structure and the resistance of these propensities to changes in tau's environment.
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Affiliation(s)
- Patrick Barré
- Department of Biochemistry, Program in Structural Biology, Weill Cornell Medical College, New York, 10065, USA
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36
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Bulic B, Pickhardt M, Mandelkow E. Progress and developments in tau aggregation inhibitors for Alzheimer disease. J Med Chem 2013; 56:4135-55. [PMID: 23484434 DOI: 10.1021/jm3017317] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Pharmacological approaches directed toward Alzheimer disease are diversifying in parallel with a growing number of promising targets. Investigations on the microtubule-associated protein tau yielded innovative targets backed by recent findings about the central role of tau in numerous neurodegenerative diseases. In this review, we summarize the recent evolution in the development of nonpeptidic small molecules tau aggregation inhibitors (TAGIs) and their advancement toward clinical trials. The compounds are classified according to their chemical structures, providing correlative insights into their pharmacology. Overall, shared structure-activity traits are emerging, as well as specific binding modes related to their ability to engage in hydrogen bonding. Medicinal chemistry efforts on TAGIs together with encouraging in vivo data argue for successful translation to the clinic.
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Affiliation(s)
- Bruno Bulic
- Laboratory of Organic Synthesis of Functional Systems, Humboldt-Universität zu Berlin, Brook-Taylor-Strasse 2, 12489 Berlin, Germany.
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37
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Ramachandran G, Udgaonkar JB. Mechanistic studies unravel the complexity inherent in tau aggregation leading to Alzheimer's disease and the tauopathies. Biochemistry 2013; 52:4107-26. [PMID: 23721410 DOI: 10.1021/bi400209z] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The aggregation of the protein tau into amyloid fibrils is known to be involved in the causation of the neurodegenerative tauopathies and the progression of cognitive decline in Alzheimer's disease. This review surveys the mechanism of tau aggregation with special emphasis on the information obtained from biochemical and biophysical studies. First, tau is described from a structure-function perspective. Subsequently, the connection of tau to neurodegeneration is explained, and a description of the tau amyloid fibril is provided. Lastly, studies of the mechanism of tau fibril formation are reviewed, and the physiological significance of these studies with reference to how they can clarify many aspects of disease progression is described. The aim of this review is to underscore how mechanistic studies reveal the complexity of the tau fibril formation pathway and the plethora of species populated on or off the pathway of aggregation, and how this information can be beneficial in the design of inhibitors or drugs that ameliorate neurodegeneration.
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Affiliation(s)
- Gayathri Ramachandran
- National Centre for Biological Sciences, Tata Institute of Fundamental Research , Bangalore 560065, India
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38
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Larini L, Gessel MM, LaPointe NE, Do TD, Bowers MT, Feinstein SC, Shea JE. Initiation of assembly of tau(273-284) and its ΔK280 mutant: an experimental and computational study. Phys Chem Chem Phys 2013; 15:8916-28. [PMID: 23515417 DOI: 10.1039/c3cp00063j] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The microtubule associated protein tau is essential for the development and maintenance of the nervous system. Tau dysfunction is associated with a class of diseases called tauopathies, in which tau is found in an aggregated form. This paper focuses on a small aggregating fragment of tau, (273)GKVQIINKKLDL(284), encompassing the (PHF6*) region that plays a central role in tau aggregation. Using a combination of simulations and experiments, we probe the self-assembly of this peptide, with an emphasis on characterizing the early steps of aggregation. Ion-mobility mass spectrometry experiments provide a size distribution of early oligomers, TEM studies provide a time course of aggregation, and enhanced sampling molecular dynamics simulations provide atomistically detailed structural information about this intrinsically disordered peptide. Our studies indicate that a point mutation, as well the addition of heparin, lead to a shift in the conformations populated by the earliest oligomers, affecting the kinetics of subsequent fibril formation as well as the morphology of the resulting aggregates. In particular, a mutant associated with a K280 deletion (a mutation that causes a heritable form of neurodegeneration/dementia in the context of full length tau) is seen to aggregate more readily than its wild-type counterpart. Simulations and experiment reveal that the ΔK280 mutant peptide adopts extended conformations to a greater extent than the wild-type peptide, facilitating aggregation through the pre-structuring of the peptide into a fibril-competent structure.
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Affiliation(s)
- Luca Larini
- Department of Physics, University of California at Santa Barbara, Santa Barbara, California 93106, USA
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39
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Wolfe MS. The role of tau in neurodegenerative diseases and its potential as a therapeutic target. SCIENTIFICA 2012; 2012:796024. [PMID: 24278740 PMCID: PMC3820460 DOI: 10.6064/2012/796024] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Accepted: 11/05/2012] [Indexed: 06/01/2023]
Abstract
The abnormal deposition of proteins in and around neurons is a common pathological feature of many neurodegenerative diseases. Among these pathological proteins, the microtubule-associated protein tau forms intraneuronal filaments in a spectrum of neurological disorders. The discovery that dominant mutations in the MAPT gene encoding tau are associated with familial frontotemporal dementia strongly supports abnormal tau protein as directly involved in disease pathogenesis. This and other evidence suggest that tau is a worthwhile target for the prevention or treatment of tau-associated neurodegenerative diseases, collectively called tauopathies. However, it is critical to understand the normal biological roles of tau, the specific molecular events that induce tau to become neurotoxic, the biochemical nature of pathogenic tau, the means by which pathogenic tau exerts neurotoxicity, and how tau pathology propagates. Based on known differences between normal and abnormal tau, a number of approaches have been taken toward the discovery of potential therapeutics. Key questions still remain open, such as the nature of the connection between the amyloid- β protein of Alzheimer's disease and tau pathology. Answers to these questions should help better understand the nature of tauopathies and may also reveal new therapeutic targets and strategies.
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Affiliation(s)
- Michael S. Wolfe
- Brigham and Women's Hospital, Harvard Medical School, 77 Avenue Louis Pasteur, H.I.M. 754, Boston, MA 02115, USA
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40
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Mo G, Zhou H, Kawamura T, Dahlquist FW. Solution structure of a complex of the histidine autokinase CheA with its substrate CheY. Biochemistry 2012; 51:3786-98. [PMID: 22494339 DOI: 10.1021/bi300147m] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
In the bacterial chemotaxis two-component signaling system, the histidine-containing phosphotransfer domain (the "P1" domain) of CheA receives a phosphoryl group from the catalytic domain (P4) of CheA and transfers it to the cognate response regulator (RR) CheY, which is docked by the P2 domain of CheA. Phosphorylated CheY then diffuses into the cytoplasm and interacts with the FliM moiety of the flagellar motors, thereby modulating the direction of flagellar rotation. Structures of various histidine phosphotransfer domains (HPt) complexed with their cognate RR domains have been reported. Unlike the Escherichia coli chemotaxis system, however, these systems lack the additional domains dedicated to binding to the response regulators, and the interaction of an HPt domain with an RR domain in the presence of such a domain has not been examined on a structural basis. In this study, we used modern nuclear magnetic resonance techniques to construct a model for the interaction of the E. coli CheA P1 domain (HPt) and CheY (RR) in the presence of the CheY-binding domain, P2. Our results indicate that the presence of P2 may lead to a slightly different relative orientation of the HPt and RR domains versus those seen in such complex structures previously reported.
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Affiliation(s)
- Guoya Mo
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106-9510, USA
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41
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Assigning backbone NMR resonances for full length tau isoforms: efficient compromise between manual assignments and reduced dimensionality. PLoS One 2012; 7:e34679. [PMID: 22529924 PMCID: PMC3329490 DOI: 10.1371/journal.pone.0034679] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Accepted: 03/08/2012] [Indexed: 11/19/2022] Open
Abstract
Tau protein is the longest disordered protein for which nearly complete backbone NMR resonance assignments have been reported. Full-length tau protein was initially assigned using a laborious combination of bootstrapping assignments from shorter tau fragments and conventional triple resonance NMR experiments. Subsequently it was reported that assignments of comparable quality could be obtained in a fully automated fashion from data obtained using reduced dimensionality NMR (RDNMR) experiments employing a large number of indirect dimensions. Although the latter strategy offers many advantages, it presents some difficulties if manual intervention, confirmation, or correction of the assignments is desirable, as may often be the case for long disordered and degenerate polypeptide sequences. Here we demonstrate that nearly complete backbone resonance assignments for full-length tau isoforms can be obtained without resorting either to bootstrapping from smaller fragments or to very high dimensionality experiments and automation. Instead, a set of RDNMR triple resonance experiments of modest dimensionality lend themselves readily to efficient and unambiguous manual assignments. An analysis of the backbone chemical shifts obtained in this fashion indicates several regions in full length tau with a notable propensity for helical or strand-like structure that are in good agreement with previous observations.
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42
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Abstract
The protein tau is the most abundant microtubule associated protein in the central and peripheral nervous system. In the brain, tau plays a role in the assembly and stabilization of microtubules. The function of tau, however, appears to overlap with other microtubule binding proteins. The observation that tau is associated with neurodegenerative diseases has renewed interest in this protein. Various aspects of structure and biochemistry of tau, fibril formation and clinical perspectives, including therapeutic strategies are reviewed in this chapter.
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43
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Moore CL, Huang MH, Robbennolt SA, Voss KR, Combs B, Gamblin TC, Goux WJ. Secondary nucleating sequences affect kinetics and thermodynamics of tau aggregation. Biochemistry 2011; 50:10876-86. [PMID: 22085312 DOI: 10.1021/bi2014745] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Tau protein was scanned for highly amyloidogenic sequences in amphiphilic motifs (X)(n)Z, Z(X)(n)Z (n ≥ 2), or (XZ)(n) (n ≥ 2), where X is a hydrophobic residue and Z is a charged or polar residue. N-Acetyl peptides homologous to these sequences were used to study aggregation. Transmission electron microscopy (TEM) showed seven peptides, in addition to well-known primary nucleating sequences Ac(275)VQIINK (AcPHF6*) and Ac(306)VQIVYK (AcPHF6), formed fibers, tubes, ribbons, or rolled sheets. Of the peptides shown by TEM to form amyloid, Ac(10)VME, AcPHF6*, Ac(375)KLTFR, and Ac(393)VYK were found to enhance the fraction of β-structure of AcPHF6 formed at equilibrium, and Ac(375)KLTFR was found to inhibit AcPHF6 and AcPHF6* aggregation kinetics in a dose-dependent manner, consistent with its participation in a hybrid steric zipper model. Single site mutants were generated which transformed predicted amyloidogenic sequences in tau into non-amyloidogenic ones. A M11K mutant had fewer filaments and showed a decrease in aggregation kinetics and an increased lag time compared to wild-type tau, while a F378K mutant showed significantly more filaments. Our results infer that sequences throughout tau, in addition to PHF6 and PHF6*, can seed amyloid formation or affect aggregation kinetics or thermodynamics.
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Affiliation(s)
- Christopher L Moore
- Department of Chemistry, The University of Texas at Dallas, Richardson, Texas 75080, United States
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Ramachandran G, Udgaonkar JB. Understanding the kinetic roles of the inducer heparin and of rod-like protofibrils during amyloid fibril formation by Tau protein. J Biol Chem 2011; 286:38948-59. [PMID: 21931162 DOI: 10.1074/jbc.m111.271874] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The aggregation of the natively disordered protein, Tau, to form lesions called neurofibrillary tangles is a characteristic feature of several neurodegenerative tauopathies. The polyanion, heparin, is commonly used as an inducer in studies of Tau aggregation in vitro, but there is surprisingly no comprehensive model describing, quantitatively, all aspects of the heparin-induced aggregation reaction. In this study, rate constants and extents of fibril formation by the four repeat domain of Tau (Tau4RD) have been reproducibly determined over a full range of heparin and protein concentrations. The kinetic role of heparin in the nucleation-dependent fibril formation reaction is shown to be limited to participation in the initial rate-limiting steps; a single heparin molecule binds two Tau4RD molecules, forming an aggregation-competent protein dimer, which then serves as a building block for further fibril growth. Importantly, the minimal kinetic model that is proposed can quantitatively account for the characteristic bell-shaped dependence of the aggregation kinetics on the stoichiometry of protein to heparin. Very importantly, this study also identifies for the first time short and thin, rod-like protofibrils that are populated transiently, early during the time course of fibril formation. The identification of these protofibrils as bona fide off-pathway species has implications for the development of therapies for tauopathies based on driving fibril formation as a means of protecting the cell from smaller, putatively toxic aggregates.
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Affiliation(s)
- Gayathri Ramachandran
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore 560065, India
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Plumley JA, Dannenberg JJ. Comparison of β-sheets of capped polyalanine with those of the tau-amyloid structures VQIVYK and VQIINK. A density functional theory study. J Phys Chem B 2011; 115:10560-6. [PMID: 21797271 DOI: 10.1021/jp205388q] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
We present ONIOM calculations using B3LYP/d95(d,p) as the high and AM1 as the low level on parallel β-sheets containing from two to ten strands of Ac-VQIVYK-NHMe and Ac-VQIINK-NHMe, as well as both parallel and antiparallel Ac-AAAAAA-NHMe. We find that the first two sequences form more stable sheets due to the additional H-bonding between the Q's in the side chains of both and the N's in the side chain of Ac-VQIINK-NHMe. However, the H-bonds in the amyloid chains are significantly weakened by attractive strain, which prevents all the interstrand H-bonds from achieving their optimal geometries simultaneously and requires high distortion energies for the individual strands in the sheets. The antiparallel Ac-AAAAAA-NHMe's are generally more stable and more cooperative than the parallel sheets, principally due to the higher distortion energies of the latter.
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Affiliation(s)
- Joshua A Plumley
- Department of Chemistry, City University of New York-Hunter College and Graduate School, 695 Park Avenue, New York, New York 10065, United States
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The Effects of Regularly Spaced Glutamine Substitutions on Alpha-Helical Peptide Structures. A DFT/ONIOM Study. Chem Phys Lett 2011; 512:255-257. [PMID: 21927063 DOI: 10.1016/j.cplett.2011.07.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The side-chains of the residues of glutamine (Q) and asparagine (N) contain amide groups. These can H-bond to each other in patterns similar to those of the backbone amides in α-helices. We show that mutating multiple Q's for alanines (A's) in a polyalanine helix stabilizes the helical structure, while similar mutations with multiple N's do not. We suggest that modification of peptides by incorporating Q's in such positions can make more robust helices that can be used to test the effects of secondary structures in biochemical experiments linked to proteins with variable structures such as tau and α-synuclein.
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Ünal C, Schwedhelm KF, Thiele A, Weiwad M, Schweimer K, Frese F, Fischer G, Hacker J, Faber C, Steinert M. Collagen IV-derived peptide binds hydrophobic cavity of Legionella pneumophila Mip and interferes with bacterial epithelial transmigration. Cell Microbiol 2011; 13:1558-72. [DOI: 10.1111/j.1462-5822.2011.01641.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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48
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Miller Y, Ma B, Nussinov R. Synergistic interactions between repeats in tau protein and Aβ amyloids may be responsible for accelerated aggregation via polymorphic states. Biochemistry 2011; 50:5172-81. [PMID: 21506544 PMCID: PMC3109766 DOI: 10.1021/bi200400u] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
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Amyloid plaques and neurofibrillary tangles simultaneously accumulate in Alzheimer’s disease (AD). It is known that Aβ and tau exist together in the mitochondria; however, the interactions between Aβ oligomers and tau are controversial. Moreover, it is still unclear which specific domains in the tau protein can interact with Aβ oligomers and what could be the effect of these interactions. Herein, we examine three different Aβ–tau oligomeric complexes. These complexes present interactions of Aβ with three domains in the tau protein; all contain high β-structure propensity in their R2, R3, and R4 repeats. Our results show that, among these, Aβ oligomers are likely to interact with the R2 domain to form a stable complex with better alignment in the turn region and the β-structure domain. We therefore propose that the R2 domain can interact with soluble Aβ oligomers and consequently promote aggregation. EM and AFM images and dimensions revealed highly polymorphic tau aggregates. We suggest that the polymorphic tau and Aβ–tau aggregates may be largely due to repeat sequences which are prone to variable turn locations along the tau repeats.
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Affiliation(s)
- Yifat Miller
- Center for Cancer Research Nanobiology Program NCI-Frederick, Frederick, MD 21702, USA
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Wang X, Lee HW, Liu Y, Prestegard JH. Structural NMR of protein oligomers using hybrid methods. J Struct Biol 2011; 173:515-29. [PMID: 21074622 PMCID: PMC3040251 DOI: 10.1016/j.jsb.2010.11.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2010] [Revised: 10/03/2010] [Accepted: 11/04/2010] [Indexed: 11/19/2022]
Abstract
Solving structures of native oligomeric protein complexes using traditional high-resolution NMR techniques remains challenging. However, increased utilization of computational platforms, and integration of information from less traditional NMR techniques with data from other complementary biophysical methods, promises to extend the boundary of NMR-applicable targets. This article reviews several of the techniques capable of providing less traditional and complementary structural information. In particular, the use of orientational constraints coming from residual dipolar couplings and residual chemical shift anisotropy offsets are shown to simplify the construction of models for oligomeric complexes, especially in cases of weak homo-dimers. Combining this orientational information with interaction site information supplied by computation, chemical shift perturbation, paramagnetic surface perturbation, cross-saturation and mass spectrometry allows high resolution models of the complexes to be constructed with relative ease. Non-NMR techniques, such as mass spectrometry, EPR and small angle X-ray scattering, are also expected to play increasingly important roles by offering alternative methods of probing the overall shape of the complex. Computational platforms capable of integrating information from multiple sources in the modeling process are also discussed in the article. And finally a new, detailed example on the determination of a chemokine tetramer structure will be used to illustrate how a non-traditional approach to oligomeric structure determination works in practice.
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Affiliation(s)
- Xu Wang
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602. USA
| | - Hsiau-Wei Lee
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602. USA
| | - Yizhou Liu
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602. USA
| | - James H. Prestegard
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602. USA
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50
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Abstract
Misfolding and subsequent self-assembly of protein molecules into various aggregates is a common molecular mechanism for a number of important human diseases. Curing protein misfolding pathologies and designing successful drugs for the inhibition or reversal of protein aggregation depends on understanding the peculiarities of the misfolding process. Protein aggregation is a very complex process characterized by a remarkable polymorphism, where soluble amyloid oligomers, amyloid fibrils and amorphous aggregates are found as final products. This polymorphism is associated with the existence of multiple independent and competing assembly pathways leading to aggregation. Regardless of the aggregation mechanism, soluble oligomers are inevitably formed during the self-association process. Some of these oligomers are now considered to be major initiators of the neurodegenerative cascades of corresponding diseases. However, not all oligomers are equally harmful, and several amyloidogenic proteins have been shown to form nontoxic oligomers, some of which were efficient fibrillation inhibitors. Unfortunately, the information on the structural properties of soluble oligomers and the mechanisms of their formation, interconversion and toxicity is sparse. This review provides an overview of some topics related to soluble oligomers and represents several illustrative examples of toxic, nontoxic, productive and off-pathway amyloid oligomers.
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Affiliation(s)
- Vladimir N Uversky
- Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
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