1
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Sari L, Bali S, Joachimiak LA, Lin MM. Hairpin trimer transition state of amyloid fibril. Nat Commun 2024; 15:2756. [PMID: 38553453 PMCID: PMC10980705 DOI: 10.1038/s41467-024-46446-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 02/28/2024] [Indexed: 04/02/2024] Open
Abstract
Protein fibril self-assembly is a universal transition implicated in neurodegenerative diseases. Although fibril structure/growth are well characterized, fibril nucleation is poorly understood. Here, we use a computational-experimental approach to resolve fibril nucleation. We show that monomer hairpin content quantified from molecular dynamics simulations is predictive of experimental fibril formation kinetics across a tau motif mutant library. Hairpin trimers are predicted to be fibril transition states; one hairpin spontaneously converts into the cross-beta conformation, templating subsequent fibril growth. We designed a disulfide-linked dimer mimicking the transition state that catalyzes fibril formation, measured by ThT fluorescence and TEM, of wild-type motif - which does not normally fibrillize. A dimer compatible with extended conformations but not the transition-state fails to nucleate fibril at any concentration. Tau repeat domain simulations show how long-range interactions sequester this motif in a mutation-dependent manner. This work implies that different fibril morphologies could arise from disease-dependent hairpin seeding from different loci.
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Affiliation(s)
- Levent Sari
- Green Center for Systems Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Lyda Hill Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Sofia Bali
- Molecular Biophysics Graduate Program, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Center for Alzheimer's and Neurodegenerative Diseases, Peter O'Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Lukasz A Joachimiak
- Center for Alzheimer's and Neurodegenerative Diseases, Peter O'Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Milo M Lin
- Green Center for Systems Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
- Lyda Hill Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, TX, USA.
- Center for Alzheimer's and Neurodegenerative Diseases, Peter O'Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA.
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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2
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Holden MR, Krzesinski BJ, Weismiller HA, Shady JR, Margittai M. MAP2 caps tau fibrils and inhibits aggregation. J Biol Chem 2023; 299:104891. [PMID: 37286038 PMCID: PMC10404690 DOI: 10.1016/j.jbc.2023.104891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 05/13/2023] [Accepted: 05/30/2023] [Indexed: 06/09/2023] Open
Abstract
Fibrils of the microtubule-associated protein tau are intimately linked to the pathology of Alzheimer's disease (AD) and related neurodegenerative disorders. A current paradigm for pathology spreading in the human brain is that short tau fibrils transfer between neurons and then recruit naive tau monomers onto their tips, perpetuating the fibrillar conformation with high fidelity and speed. Although it is known that the propagation could be modulated in a cell-specific manner and thereby contribute to phenotypic diversity, there is still limited understanding of how select molecules are involved in this process. MAP2 is a neuronal protein that shares significant sequence homology with the repeat-bearing amyloid core region of tau. There is discrepancy about MAP2's involvement in pathology and its relationship with tau fibrillization. Here, we employed the entire repeat regions of 3R and 4R MAP2, to investigate their modulatory role in tau fibrillization. We find that both proteins block the spontaneous and seeded aggregation of 4R tau, with 4R MAP2 being slightly more potent. The inhibition of tau seeding is observed in vitro, in HEK293 cells, and in AD brain extracts, underscoring its broader scope. MAP2 monomers specifically bind to the end of tau fibrils, preventing recruitment of further tau and MAP2 monomers onto the fibril tip. The findings uncover a new function for MAP2 as a tau fibril cap that could play a significant role in modulating tau propagation in disease and may hold promise as a potential intrinsic protein inhibitor.
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Affiliation(s)
- Michael R Holden
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado, USA
| | - Brad J Krzesinski
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado, USA
| | - Hilary A Weismiller
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado, USA
| | - Justin R Shady
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado, USA
| | - Martin Margittai
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado, USA.
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3
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Melková K, Zapletal V, Narasimhan S, Jansen S, Hritz J, Škrabana R, Zweckstetter M, Ringkjøbing Jensen M, Blackledge M, Žídek L. Structure and Functions of Microtubule Associated Proteins Tau and MAP2c: Similarities and Differences. Biomolecules 2019; 9:biom9030105. [PMID: 30884818 PMCID: PMC6468450 DOI: 10.3390/biom9030105] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 03/09/2019] [Accepted: 03/13/2019] [Indexed: 12/16/2022] Open
Abstract
The stability and dynamics of cytoskeleton in brain nerve cells are regulated by microtubule associated proteins (MAPs), tau and MAP2. Both proteins are intrinsically disordered and involved in multiple molecular interactions important for normal physiology and pathology of chronic neurodegenerative diseases. Nuclear magnetic resonance and cryo-electron microscopy recently revealed propensities of MAPs to form transient local structures and long-range contacts in the free state, and conformations adopted in complexes with microtubules and filamentous actin, as well as in pathological aggregates. In this paper, we compare the longest, 441-residue brain isoform of tau (tau40), and a 467-residue isoform of MAP2, known as MAP2c. For both molecules, we present transient structural motifs revealed by conformational analysis of experimental data obtained for free soluble forms of the proteins. We show that many of the short sequence motifs that exhibit transient structural features are linked to functional properties, manifested by specific interactions. The transient structural motifs can be therefore classified as molecular recognition elements of tau40 and MAP2c. Their interactions are further regulated by post-translational modifications, in particular phosphorylation. The structure-function analysis also explains differences between biological activities of tau40 and MAP2c.
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Affiliation(s)
- Kateřina Melková
- Central European Institute of Technology, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic.
- Faculty of Science, National Centre for Biomolecular Research, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic.
| | - Vojtěch Zapletal
- Central European Institute of Technology, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic.
- Faculty of Science, National Centre for Biomolecular Research, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic.
| | - Subhash Narasimhan
- Central European Institute of Technology, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic.
| | - Séverine Jansen
- Central European Institute of Technology, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic.
| | - Jozef Hritz
- Central European Institute of Technology, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic.
| | - Rostislav Škrabana
- Institute of Neuroimmunology, Slovak Academy of Sciences, Dúbravská cesta 9, 845 10 Bratislava, Slovakia.
- Axon Neuroscience R&D Services SE, Dvořákovo nábrežie 10, 811 02 Bratislava, Slovakia.
| | - Markus Zweckstetter
- German Center for Neurodegenerative Diseases (DZNE), Von-Siebold-Str. 3a, 37075 Göttingen, Germany.
- Department of NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany.
| | | | | | - Lukáš Žídek
- Central European Institute of Technology, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic.
- Faculty of Science, National Centre for Biomolecular Research, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic.
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4
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Petry FR, Nicholls SB, Hébert SS, Planel E. A Simple Method to Avoid Nonspecific Signal When Using Monoclonal Anti-Tau Antibodies in Western Blotting of Mouse Brain Proteins. Methods Mol Biol 2017; 1523:263-272. [PMID: 27975255 DOI: 10.1007/978-1-4939-6598-4_15] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In Alzheimer's disease and other tauopathies, tau displays several abnormal post-translation modifications such as hyperphosphorylation, truncation, conformation, and oligomerization. Mouse monoclonal antibodies have been raised against such tau modifications for research, diagnostic, and therapeutic purposes. However, many of these primary antibodies are at risk of giving nonspecific signals in common Western blotting procedures. Not because they are unspecific, but because the secondary antibodies used to detect them will also detect the heavy chain of endogenous mouse immunoglobulins (Igs), and give a nonspecific signal at the same molecular weight than tau protein (around 50 kDa). Here, we propose the use of anti-light chain secondary antibodies as a simple and efficient technique to prevent nonspecific Igs signals at around 50 kDa. We demonstrate the efficacy of this method by removing artifactual signals when using monoclonal antibodies directed at tau phosphorylation (AT100, 12E8, AT270), tau truncation (TauC3), tau oligomerization (TOMA), or tau abnormal conformation (Alz50), in wild-type, 3×Tg-AD, and tau knockout mice.
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Affiliation(s)
- Franck R Petry
- Département de psychiatrie et neurosciences, Université Laval, Québec, QC, Canada
| | - Samantha B Nicholls
- Department of Neurology, MassGeneral Institute for Neurodegenerative Disease, Alzheimer's Disease Research Laboratory, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Sébastien S Hébert
- Département de psychiatrie et neurosciences, Université Laval, Québec, QC, Canada
- Centre de Recherche du CHU de Québec, Neurosciences, Québec, QC, Canada
| | - Emmanuel Planel
- Département de psychiatrie et neurosciences, Université Laval, Québec, QC, Canada.
- Centre de Recherche du CHU de Québec, Neurosciences, Québec, QC, Canada.
- Centre Hospitalier de l'Université Laval (CHUL), P0-9800, 2705 Boulevard Laurier, Québec, QC, Canada, G1V 4G2.
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5
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Georgieva ER, Xiao S, Borbat PP, Freed JH, Eliezer D. Tau binds to lipid membrane surfaces via short amphipathic helices located in its microtubule-binding repeats. Biophys J 2015; 107:1441-52. [PMID: 25229151 DOI: 10.1016/j.bpj.2014.07.046] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Revised: 07/18/2014] [Accepted: 07/24/2014] [Indexed: 11/16/2022] Open
Abstract
Tau is a microtubule-associated protein that is genetically linked to dementia and linked to Alzheimer's disease via its presence in intraneuronal neurofibrillary tangle deposits, where it takes the form of aggregated paired helical and straight filaments. Although the precise mechanisms by which tau contributes to neurodegeneration remain unclear, tau aggregation is commonly considered to be a critical component of tau-mediated pathogenicity. Nevertheless, the context in which tau aggregation begins in vivo is unknown. Tau is enriched in membrane-rich neuronal structures such as axons and growth cones, and can interact with membranes both via intermediary proteins and directly via its microtubule-binding domain (MBD). Membranes efficiently facilitate tau aggregation in vitro, and may therefore provide a physiologically relevant context for nucleating tau aggregation in vivo. Furthermore, tau-membrane interactions may potentially play a role in tau's poorly understood normal physiological functions. Despite the potential importance of direct tau-membrane interactions for tau pathology and physiology, the structural mechanisms that underlie such interactions remain to be elucidated. Here, we employ electron spin resonance spectroscopy to investigate the secondary and long-range structural properties of the MBD of three-repeat tau isoforms when bound to lipid vesicles and membrane mimetics. We show that the membrane interactions of the tau MBD are mediated by short amphipathic helices formed within each of the MBD repeats in the membrane-bound state. To our knowledge, this is the first detailed elucidation of helical tau structure in the context of intact lipid bilayers. We further show, for the first time (to our knowledge), that these individual helical regions behave as independent membrane-binding sites linked by flexible connecting regions. These results represent the first (to our knowledge) detailed structural view of membrane-bound tau and provide insights into potential mechanisms for membrane-mediated tau aggregation. Furthermore, the results may have implications for the structural basis of tau-microtubule interactions and microtubule-mediated tau aggregation.
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Affiliation(s)
- Elka R Georgieva
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York; National Biomedical Center for Advanced ESR Technology, Cornell University, Ithaca, New York
| | - Shifeng Xiao
- Department of Biochemistry, Weill Cornell Medical College, New York, New York; Program in Structural Biology, Weill Cornell Medical College, New York, New York
| | - Peter P Borbat
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York; National Biomedical Center for Advanced ESR Technology, Cornell University, Ithaca, New York
| | - Jack H Freed
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York; National Biomedical Center for Advanced ESR Technology, Cornell University, Ithaca, New York.
| | - David Eliezer
- Department of Biochemistry, Weill Cornell Medical College, New York, New York; Program in Structural Biology, Weill Cornell Medical College, New York, New York.
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6
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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: 56] [Impact Index Per Article: 5.1] [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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7
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Adams SJ, DeTure MA, McBride M, Dickson DW, Petrucelli L. Three repeat isoforms of tau inhibit assembly of four repeat tau filaments. PLoS One 2010; 5:e10810. [PMID: 20520830 PMCID: PMC2876030 DOI: 10.1371/journal.pone.0010810] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2010] [Accepted: 04/30/2010] [Indexed: 11/18/2022] Open
Abstract
Tauopathies are defined by assembly of the microtubule associated protein tau into filamentous tangles and classified by the predominant tau isoform within these aggregates. The major isoforms are determined by alternative mRNA splicing of exon 10 generating tau with three (3R) or four (4R) ∼32 amino acid imperfect repeats in the microtubule binding domain. In normal adult brains there is an approximately equimolar ratio of 3R and 4R tau which is altered by several disease-causing mutations in the tau gene. We hypothesized that when 4R and 3R tau isoforms are not at equimolar ratios aggregation is favored. Here we provide evidence for the first time that the combination of 3R and 4R tau isoforms results in less in vitro heparin induced polymerization than with 4R preparations alone. This effect was independent of reducing conditions and the presence of alternatively spliced exons 2 and 3 N-terminal inserts. The addition of even small amounts of 3R to 4R tau assembly reactions significantly decreased 4R assembly. Together these findings suggest that co-expression of 3R and 4R tau isoforms reduce tau filament assembly and that 3R tau isoforms inhibit 4R tau assembly. Expression of equimolar amounts of 3R and 4R tau in adult humans may be necessary to maintain proper neuronal microtubule dynamics and to prevent abnormal tau filament assembly. Importantly, these findings indicate that disruption of the normal equimolar 3R to 4R ratio may be sufficient to drive tau aggregation and that restoration of the tau isoform balance may have important therapeutic implications in tauopathies.
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Affiliation(s)
- Stephanie J. Adams
- Department of Neuroscience, Mayo Clinic College of Medicine, Jacksonville, Florida, United States of America
| | - Michael A. DeTure
- Department of Neuroscience, Mayo Clinic College of Medicine, Jacksonville, Florida, United States of America
- * E-mail: (LP); (MAD)
| | - Melinda McBride
- Department of Neuroscience, Mayo Clinic College of Medicine, Jacksonville, Florida, United States of America
| | - Dennis W. Dickson
- Department of Neuroscience, Mayo Clinic College of Medicine, Jacksonville, Florida, United States of America
| | - Leonard Petrucelli
- Department of Neuroscience, Mayo Clinic College of Medicine, Jacksonville, Florida, United States of America
- * E-mail: (LP); (MAD)
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8
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Nakamura T, Myint KT, Oda Y. Ethylenediaminetetraacetic Acid Increases Identification Rate of Phosphoproteomics in Real Biological Samples. J Proteome Res 2010; 9:1385-91. [DOI: 10.1021/pr900918h] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Tatsuji Nakamura
- Eisai Company, Ltd., Biomarkers and Personalized Medicine Unit, Tsukuba, Ibaraki 300-2635, Japan, Eisai Company, Ltd., Biomarkers and Personalized Medicine Unit, Andover, Massachusetts 01810, and Core Research for Evolutional Science and Technology, Japan Science and Technology, Saitama 332-0012, Japan
| | - Khin Than Myint
- Eisai Company, Ltd., Biomarkers and Personalized Medicine Unit, Tsukuba, Ibaraki 300-2635, Japan, Eisai Company, Ltd., Biomarkers and Personalized Medicine Unit, Andover, Massachusetts 01810, and Core Research for Evolutional Science and Technology, Japan Science and Technology, Saitama 332-0012, Japan
| | - Yoshiya Oda
- Eisai Company, Ltd., Biomarkers and Personalized Medicine Unit, Tsukuba, Ibaraki 300-2635, Japan, Eisai Company, Ltd., Biomarkers and Personalized Medicine Unit, Andover, Massachusetts 01810, and Core Research for Evolutional Science and Technology, Japan Science and Technology, Saitama 332-0012, Japan
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9
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Mandelkow E, von Bergen M, Biernat J, Mandelkow EM. Structural principles of tau and the paired helical filaments of Alzheimer's disease. Brain Pathol 2007; 17:83-90. [PMID: 17493042 PMCID: PMC8095506 DOI: 10.1111/j.1750-3639.2007.00053.x] [Citation(s) in RCA: 163] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Tau, a major microtubule-associated protein in brain, forms abnormal fibers in Alzheimer's disease and several other neurodegenerative diseases. Tau is highly soluble and adopts a natively unfolded structure in solution. In the paired helical filaments of Alzheimer's disease, small segments of tau adopt a beta-conformation and interact with other tau molecules. In the filament core, the microtubule-binding repeat region of tau has a cross-beta structure, while the rest of the protein retains its largely unfolded structure and gives rise to the fuzzy coat of the filaments.
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10
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Mukrasch MD, von Bergen M, Biernat J, Fischer D, Griesinger C, Mandelkow E, Zweckstetter M. The "jaws" of the tau-microtubule interaction. J Biol Chem 2007; 282:12230-9. [PMID: 17307736 DOI: 10.1074/jbc.m607159200] [Citation(s) in RCA: 144] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Tau is the major microtubule-associated protein in neuronal axons. It aggregates into "neurofibrillary tangles" during the course of Alzheimer disease. Binding to microtubules and microtubule assembly requires the "repeat domain" in the C-terminal half of Tau, as well as the two regions flanking the repeats. Here we report the NMR characterization of a 198-residue Tau fragment composed of the four tandem repeats and the flanking domains and containing the full microtubule binding and assembly activity of Tau. NMR secondary chemical shifts and dipolar couplings detect the highest propensity for beta-structure within the four-repeat region, whereas the flanking domains are largely random coil, with an increased rigidity in the proline-rich region. Chemical shift perturbation experiments identify two motifs in the upstream flanking domain, (225)KVAVVRT(231) and (243)LQTA(246), and one downstream of the repeats, (370)KIETHKTFREN(380), which strongly contribute to the binding to the acidic outside of microtubules, as well as to the binding of other polyanions such as heparin. This is consistent with the "jaws" model of Tau-microtubule interactions and highlights the importance of the regions flanking the repeats for both microtubule binding and pathological Tau aggregation.
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Affiliation(s)
- Marco D Mukrasch
- Department for NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen
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11
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Dinoto L, Deture MA, Purich DL. Structural insights into Alzheimer filament assembly pathways based on site-directed mutagenesis and S-glutathionylation of three-repeat neuronal Tau protein. Microsc Res Tech 2006; 67:156-63. [PMID: 16104002 DOI: 10.1002/jemt.20195] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Although Tau and MAP2 readily assemble into straight filaments (SFs), Tau's unique ability to form paired-helical filaments (PHFs) may offer clues as to why Tau's microtubule-binding region (MTBR) is the exclusive building block of the neurofibrillary tangles that accumulate during Alzheimer's disease. To learn more about the factors permitting Tau to form both SFs and PHFs, we investigated the microtubule binding, thiol oxidation, and polymerization reactions of the monomer and dimer forms of Tau and MAP2 MTBRs. This review focuses on electron microscopic evidence (1) that facilitated the identification of amino acid residues within 3-repeat Tau that promote PHF formation; and (2) provided experimental evidence for the polymerization of S-glutathionylated three-repeat Tau, a reaction that unambiguously demonstrates that disulfide-linked Tau-S-S-Tau dimer formation is not a compulsory step in filament assembly. We also consider these findings within the context of current views on the genetic and biochemical basis of Tau fibrillogenesis.
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Affiliation(s)
- Luca Dinoto
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, Gainesville, Florida 32610-0245, USA
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12
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DeTure M, Granger B, Grover A, Hutton M, Yen SH. Evidence for independent mechanisms and a multiple-hit model of tau assembly. Biochem Biophys Res Commun 2005; 339:858-64. [PMID: 16325769 DOI: 10.1016/j.bbrc.2005.11.087] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2005] [Accepted: 11/16/2005] [Indexed: 11/21/2022]
Abstract
Formation of inclusions containing polymerized tau protein is a hallmark of Alzheimer's disease and related disorders. In vitro studies have demonstrated the ability of polyglycosaminoglycans and fatty acids to promote tau polymerization. In this report, we examined their impact on tau polymerization separately and together. Tau assembly with only arachidonic acid was faster than that with only heparin. The presence of dithiothreitol reduced heparin-promoted tau assembly while enhancing arachidonic acid reactions. However, simultaneous use of these molecules increased the rate of filament assembly substantially, negated the effects of the reducing agent, and has very little effect on the morphology of filaments. The increases in polymerization resulted from accelerated nucleation. Finally, a FTDP-17 mutation was identified that could complement heparin to generate assembly kinetics similar to that of wild-type tau with both inducers. Our results support a multiple-hit model where several induced changes in tau can function independently to promote tau assembly.
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Affiliation(s)
- Michael DeTure
- Department of Neuroscience, Mayo Clinic Jacksonville, Jacksonville, FL 32224, USA
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13
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Avila J, Lucas JJ, Perez M, Hernandez F. Role of tau protein in both physiological and pathological conditions. Physiol Rev 2004; 84:361-84. [PMID: 15044677 DOI: 10.1152/physrev.00024.2003] [Citation(s) in RCA: 656] [Impact Index Per Article: 32.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The morphology of a neuron is determined by its cytoskeletal scaffolding. Thus proteins that associate with the principal cytoskeletal components such as the microtubules have a strong influence on both the morphology and physiology of neurons. Tau is a microtubule-associated protein that stabilizes neuronal microtubules under normal physiological conditions. However, in certain pathological situations, tau protein may undergo modifications, mainly through phosphorylation, that can result in the generation of aberrant aggregates that are toxic to neurons. This process occurs in a number of neurological disorders collectively known as tauopathies, the most commonly recognized of which is Alzheimer's disease. The purpose of this review is to define the role of tau protein under normal physiological conditions and to highlight the role of the protein in different tauopathies.
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Affiliation(s)
- Jesus Avila
- Centro de Biología Molecular "Severo Ochoa", Facultad de Ciencias, Campus de Cantoblanco, Universidad Autónoma de Madrid, 28049 Madrid, Spain.
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14
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Grover A, England E, Baker M, Sahara N, Adamson J, Granger B, Houlden H, Passant U, Yen SH, DeTure M, Hutton M. A novel tau mutation in exon 9 (1260V) causes a four-repeat tauopathy. Exp Neurol 2004; 184:131-40. [PMID: 14637086 DOI: 10.1016/s0014-4886(03)00393-5] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A novel mutation in exon 9 of tau, I260V, is associated with a clinical syndrome consistent with frontotemporal dementia with extensive tau pathology; however, neurofibrillary tangles and Pick bodies are absent. Significantly, Sarkosyl-insoluble tau extracted from affected brain tissue consisted almost exclusively of four-repeat isoforms. Consistent with these findings, in vitro biochemical assays demonstrated that the I260V mutation causes a selective increase in tau aggregation and a decrease in tau-induced microtubule assembly with four-repeat isoforms only. The contrasting pathology and biochemical effects of this mutation suggest a different disease mechanism from the other exon 9 mutations and demonstrates the critical role for the first microtubule-binding domain in tau-promoted microtubule assembly and the pathogenic aggregation of tau.
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Affiliation(s)
- Andrew Grover
- Laboratory of Neurogenetics, Neuroscience Department, Mayo Clinic, Jacksonville, FL 32224, USA
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15
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Abstract
Aging is the major risk factor for numerous brain diseases. This is especially true for Alzheimer's disease (AD), a peculiar neurodegenerative disorder in that it results from the synergy of two simultaneous but distinct degenerating processes: A beta and tau pathologies. For AD, and for most neurodegenerative disorders, aggregation of full length or truncated proteins, in neurons or glial cells, or in the parenchyma, is central, but still a mystery. In addition, the late onset of these pathologies links them to ageing processes. Cause or consequence? Experimental models, that allow us to dissect these pathophysiological defects, are presented.
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Affiliation(s)
- André Delacourte
- INSERM U422, Institut de Médecine Prédictive et Recherche Thérapeutique, Place de Verdun, 59045 Lille, France
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Barghorn S, Mandelkow E. Toward a unified scheme for the aggregation of tau into Alzheimer paired helical filaments. Biochemistry 2002; 41:14885-96. [PMID: 12475237 DOI: 10.1021/bi026469j] [Citation(s) in RCA: 250] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Alzheimer's disease is characterized by aggregates of tau protein. Attempts to study the conditions for aggregation in vitro have led to different experimental systems, some of which appear mutually exclusive (e.g., oxidative vs reductive conditions, induction by polyanions vs fatty acids). We show here that different approaches and pathways can be viewed in a common framework, and that apparent differences can be explained by variations in the kinetics of subreactions. A unified view of PHF aggregation should help to analyze the causes of PHF aggregation and devise methods to prevent it.
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Affiliation(s)
- S Barghorn
- Max-Planck-Unit for Structural Molecular Biology, Notkestrasse 85, 22607 Hamburg, Germany
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