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Meng L, Liu C, Liu M, Chen J, Liu C, Zhang Z, Chen G, Zhang Z. The yeast protein Ure2p triggers Tau pathology in a mouse model of tauopathy. Cell Rep 2023; 42:113342. [PMID: 37897723 DOI: 10.1016/j.celrep.2023.113342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 06/28/2023] [Accepted: 10/10/2023] [Indexed: 10/30/2023] Open
Abstract
The molecular mechanisms that trigger Tau aggregation in Alzheimer's disease (AD) remain elusive. Fungi, especially Saccharomyces cerevisiae (S. cerevisiae), can be found in brain samples from patients with AD. Here, we show that the yeast protein Ure2p from S. cerevisiae interacts with Tau and facilitates its aggregation. The Ure2p-seeded Tau fibrils are more potent in seeding Tau and causing neurotoxicity in vitro. When injected into the hippocampus of Tau P301S transgenic mice, the Ure2p-seeded Tau fibrils show enhanced seeding activity compared with pure Tau fibrils. Strikingly, intracranial injection of Ure2p fibrils promotes the aggregation of Tau and cognitive impairment in Tau P301S mice. Furthermore, intranasal infection of S. cerevisiae in the nasal cavity of Tau P301S mice accelerates the aggregation of Tau. Together, these observations indicate that the yeast protein Ure2p initiates Tau pathology. Our results provide a conceptual advance that non-mammalian prions may cross-seed mammalian prion-like proteins.
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Affiliation(s)
- Lanxia Meng
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan 430060, China
| | - Congcong Liu
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan 430060, China
| | - Miao Liu
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan 430060, China
| | - Jiehui Chen
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan 430060, China
| | - Chaoyang Liu
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan 430060, China; Research Center for Environment and Health, Zhongnan University of Economics and Law, Wuhan 430073, China
| | - Zhaohui Zhang
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan 430060, China
| | - Guiqin Chen
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan 430060, China; Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Zhentao Zhang
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan 430060, China; TaiKang Center for Life and Medical Sciences, Wuhan University, Wuhan 430000, China.
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Devi S, Garg DK, Bhat R. Kinetic control in amyloid polymorphism: Different agitation and solution conditions promote distinct amyloid polymorphs of alpha-synuclein. BIOCHIMICA ET BIOPHYSICA ACTA. PROTEINS AND PROTEOMICS 2023; 1871:140917. [PMID: 37061153 DOI: 10.1016/j.bbapap.2023.140917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 04/01/2023] [Accepted: 04/11/2023] [Indexed: 04/17/2023]
Abstract
Aggregation of neuronal protein α-synuclein is implicated in synucleinopathies, including Parkinson's disease. Despite abundant in vitro studies, the mechanism of α-synuclein assembly process remains ambiguous. In this work, α-synuclein aggregation was induced by its constant mixing in two separate modes, either by agitation in a 96-well microplate reader (MP) or in microcentrifuge tubes using a shaker incubator (SI). Aggregation in both modes occurred through a sigmoidal growth pattern with a well-defined lag, growth, and saturation phase. The end-stage MP- and SI-derived aggregates displayed distinct differences in morphological, biochemical, and spectral signatures as discerned through AFM, proteinase-K digestion, FTIR, Raman, and CD spectroscopy. The MP-derived aggregates showed irregular morphology with a significant random coil conformation, contrary to SI-derived aggregates, which showed typical β-sheet fibrillar structures. The end-stage MP aggregates convert to β-rich SI-like aggregates upon 1) seeding with SI-derived aggregates and 2) agitating in SI. We conclude that end-stage MP aggregates were in a kinetically trapped conformation, whose kinetic barrier was bypassed upon either seeding by SI-derived fibrils or shaking in SI. We further show that MP-derived aggregates that form in the presence of sorbitol, an osmolyte, displayed a β-rich signature, indicating that the preferential exclusion effect of osmolytes helped overcome the kinetic barrier. Our findings help in unravelling the kinetic origin of different α-synuclein aggregated polymorphs (strains) that encode diverse variants of synucleinopathies. We demonstrate that kinetic control shapes the polymorphic landscape of α-synuclein aggregates, both through de novo generation of polymorphs, and by their interconversion.
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Affiliation(s)
- Santosh Devi
- School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India
| | - Dushyant Kumar Garg
- School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India
| | - Rajiv Bhat
- School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India.
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Wickner RB, Edskes HK, Son M, Wu S. Anti-Prion Systems Block Prion Transmission, Attenuate Prion Generation, Cure Most Prions as They Arise and Limit Prion-Induced Pathology in Saccharomyces cerevisiae. BIOLOGY 2022; 11:biology11091266. [PMID: 36138748 PMCID: PMC9495834 DOI: 10.3390/biology11091266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 08/08/2022] [Accepted: 08/16/2022] [Indexed: 11/16/2022]
Abstract
Simple Summary Virus and bacterial infections are opposed by their hosts at many levels. Similarly, we find that infectious proteins (prions) are severely restricted by an array of host systems, acting independently to prevent infection, generation, propagation and the ill effects of yeast prions. These ‘anti-prion systems’ work in normal cells without the overproduction or deficiency of any components. DNA repair systems reverse the effects of DNA damage, with only a rare lesion propagated as a mutation. Similarly, the combined effects of several anti-prion systems cure and block the generation of all but 1 in about 5000 prions arising. We expect that application of our approach to mammalian cells will detect analogous or even homologous systems that will be useful in devising therapy for human amyloidoses, most of which are prions. Abstract All variants of the yeast prions [PSI+] and [URE3] are detrimental to their hosts, as shown by the dramatic slowing of growth (or even lethality) of a majority, by the rare occurrence in wild isolates of even the mildest variants and by the absence of reproducible benefits of these prions. To deal with the prion problem, the host has evolved an array of anti-prion systems, acting in normal cells (without overproduction or deficiency of any component) to block prion transmission from other cells, to lower the rates of spontaneous prion generation, to cure most prions as they arise and to limit the damage caused by those variants that manage to elude these (necessarily) imperfect defenses. Here we review the properties of prion protein sequence polymorphisms Btn2, Cur1, Hsp104, Upf1,2,3, ribosome-associated chaperones, inositol polyphosphates, Sis1 and Lug1, which are responsible for these anti-prion effects. We recently showed that the combined action of ribosome-associated chaperones, nonsense-mediated decay factors and the Hsp104 disaggregase lower the frequency of [PSI+] appearance as much as 5000-fold. Moreover, while Btn2 and Cur1 are anti-prion factors against [URE3] and an unrelated artificial prion, they promote [PSI+] prion generation and propagation.
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Innate immunity to prions: anti-prion systems turn a tsunami of prions into a slow drip. Curr Genet 2021; 67:833-847. [PMID: 34319422 DOI: 10.1007/s00294-021-01203-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 07/06/2021] [Accepted: 07/07/2021] [Indexed: 12/17/2022]
Abstract
The yeast prions (infectious proteins) [URE3] and [PSI+] are essentially non-functional (or even toxic) amyloid forms of Ure2p and Sup35p, whose normal function is in nitrogen catabolite repression and translation termination, respectively. Yeast has an array of systems working in normal cells that largely block infection with prions, block most prion formation, cure most nascent prions and mitigate the toxic effects of those prions that escape the first three types of systems. Here we review recent progress in defining these anti-prion systems, how they work and how they are regulated. Polymorphisms of the prion domains partially block infection with prions. Ribosome-associated chaperones ensure proper folding of nascent proteins, thus reducing [PSI+] prion formation and curing many [PSI+] variants that do form. Btn2p is a sequestering protein which gathers [URE3] amyloid filaments to one place in the cells so that the prion is often lost by progeny cells. Proteasome impairment produces massive overexpression of Btn2p and paralog Cur1p, resulting in [URE3] curing. Inversely, increased proteasome activity, by derepression of proteasome component gene transcription or by 60S ribosomal subunit gene mutation, prevents prion curing by Btn2p or Cur1p. The nonsense-mediated decay proteins (Upf1,2,3) cure many nascent [PSI+] variants by associating with Sup35p directly. Normal levels of the disaggregating chaperone Hsp104 can also cure many [PSI+] prion variants. By keeping the cellular levels of certain inositol polyphosphates / pyrophosphates low, Siw14p cures certain [PSI+] variants. It is hoped that exploration of the yeast innate immunity to prions will lead to discovery of similar systems in humans.
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Liu EN, Park G, Nohara J, Guo Z. Effect of spin labelling on the aggregation kinetics of yeast prion protein Ure2. ROYAL SOCIETY OPEN SCIENCE 2021; 8:201747. [PMID: 33959337 PMCID: PMC8074925 DOI: 10.1098/rsos.201747] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 02/10/2021] [Indexed: 06/12/2023]
Abstract
Amyloid formation is involved in a wide range of neurodegenerative diseases including Alzheimer's and prion diseases. Structural understanding of the amyloid is critical to delineate the mechanism of aggregation and its pathological spreading. Site-directed spin labelling has emerged as a powerful structural tool in the studies of amyloid structures and provided structural evidence for the parallel in-register β-sheet structure for a wide range of amyloid proteins. It is generally accepted that spin labelling does not disrupt the structure of the amyloid fibrils, the end product of protein aggregation. The effect on the rate of protein aggregation, however, has not been well characterized. Here, we employed a scanning mutagenesis approach to study the effect of spin labelling on the aggregation rate of 79 spin-labelled variants of the Ure2 prion domain. The aggregation of Ure2 protein is the basis of yeast prion [URE3]. We found that all spin-labelled Ure2 mutants aggregated within the experimental timeframe of 15 to 40 h. Among the 79 spin-labelled positions, only five residue sites (N23, N27, S33, I35 and G42) showed a dramatic delay in the aggregation rate as a result of spin labelling. These positions may be important for fibril nucleation, a rate-limiting step in aggregation. Importantly, spin labelling at most of the sites had a muted effect on Ure2 aggregation kinetics, showing a general tolerance of spin labelling in protein aggregation studies.
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Affiliation(s)
- Emilie N. Liu
- Department of Neurology, Brain Research Institute, Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA
| | - Giovanna Park
- Department of Neurology, Brain Research Institute, Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA
| | - Junsuke Nohara
- Department of Neurology, Brain Research Institute, Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA
| | - Zhefeng Guo
- Department of Neurology, Brain Research Institute, Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA
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Scherpelz KP, Wang S, Pytel P, Madhurapantula RS, Srivastava AK, Sachleben JR, Orgel J, Ishii Y, Meredith SC. Atomic-level differences between brain parenchymal- and cerebrovascular-seeded Aβ fibrils. Sci Rep 2021; 11:247. [PMID: 33420184 PMCID: PMC7794565 DOI: 10.1038/s41598-020-80042-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 12/02/2020] [Indexed: 11/24/2022] Open
Abstract
Alzheimer's disease is characterized by neuritic plaques, the main protein components of which are β-amyloid (Aβ) peptides deposited as β-sheet-rich amyloid fibrils. Cerebral Amyloid Angiopathy (CAA) consists of cerebrovascular deposits of Aβ peptides; it usually accompanies Alzheimer's disease, though it sometimes occurs in the absence of neuritic plaques, as AD also occurs without accompanying CAA. Although neuritic plaques and vascular deposits have similar protein compositions, one of the characteristic features of amyloids is polymorphism, i.e., the ability of a single pure peptide to adopt multiple conformations in fibrils, depending on fibrillization conditions. For this reason, we asked whether the Aβ fibrils in neuritic plaques differed structurally from those in cerebral blood vessels. To address this question, we used seeding techniques, starting with amyloid-enriched material from either brain parenchyma or cerebral blood vessels (using meninges as the source). These amyloid-enriched preparations were then added to fresh, disaggregated solutions of Aβ to make replicate fibrils, as described elsewhere. Such fibrils were then studied by solid-state NMR, fiber X-ray diffraction, and other biophysical techniques. We observed chemical shift differences between parenchymal vs. vascular-seeded replicate fibrils in select sites (in particular, Ala2, Phe4, Val12, and Gln15 side chains) in two-dimensional 13C-13C correlation solid-state NMR spectra, strongly indicating structural differences at these sites. X-ray diffraction studies also indicated that vascular-seeded fibrils displayed greater order than parenchyma-seeded fibrils in the "side-chain dimension" (~ 10 Å reflection), though the "hydrogen-bond dimensions" (~ 5 Å reflection) were alike. These results indicate that the different nucleation conditions at two sites in the brain, parenchyma and blood vessels, affect the fibril products that get formed at each site, possibly leading to distinct pathophysiological outcomes.
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Affiliation(s)
| | - Songlin Wang
- Department of Chemistry, University of Illinois At Chicago, Chicago, IL, 60607, USA
| | - Peter Pytel
- Department of Pathology, The University of Chicago, Chicago, IL, 60637, USA
| | - Rama S Madhurapantula
- Department of Biology and Biomedical Engineering, Illinois Institute of Technology, Chicago, IL, USA
| | - Atul K Srivastava
- Department of Pathology, The University of Chicago, Chicago, IL, 60637, USA
| | - Joseph R Sachleben
- Biomolecular NMR Facility, The University of Chicago, Chicago, IL, 60637, USA
| | - Joseph Orgel
- Department of Biology and Biomedical Engineering, Illinois Institute of Technology, Chicago, IL, USA
| | - Yoshitaka Ishii
- School of Life Science and Technology, Tokyo Institute of Technology, 4259 Midori-ku, Yokohama, Kanagawa, 226-8503, Japan
| | - Stephen C Meredith
- Department of Pathology, The University of Chicago, Chicago, IL, 60637, USA.
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, 60637, USA.
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Wickner RB, Edskes HK, Son M, Wu S, Niznikiewicz M. How Do Yeast Cells Contend with Prions? Int J Mol Sci 2020; 21:ijms21134742. [PMID: 32635197 PMCID: PMC7369894 DOI: 10.3390/ijms21134742] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 06/26/2020] [Accepted: 06/30/2020] [Indexed: 12/11/2022] Open
Abstract
Infectious proteins (prions) include an array of human (mammalian) and yeast amyloid diseases in which a protein or peptide forms a linear β-sheet-rich filament, at least one functional amyloid prion, and two functional infectious proteins unrelated to amyloid. In Saccharomyces cerevisiae, at least eight anti-prion systems deal with pathogenic amyloid yeast prions by (1) blocking their generation (Ssb1,2, Ssz1, Zuo1), (2) curing most variants as they arise (Btn2, Cur1, Hsp104, Upf1,2,3, Siw14), and (3) limiting the pathogenicity of variants that do arise and propagate (Sis1, Lug1). Known mechanisms include facilitating proper folding of the prion protein (Ssb1,2, Ssz1, Zuo1), producing highly asymmetric segregation of prion filaments in mitosis (Btn2, Hsp104), competing with the amyloid filaments for prion protein monomers (Upf1,2,3), and regulation of levels of inositol polyphosphates (Siw14). It is hoped that the discovery of yeast anti-prion systems and elucidation of their mechanisms will facilitate finding analogous or homologous systems in humans, whose manipulation may be useful in treatment.
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Polymorphic Aβ42 fibrils adopt similar secondary structure but differ in cross-strand side chain stacking interactions within the same β-sheet. Sci Rep 2020; 10:5720. [PMID: 32235842 PMCID: PMC7109039 DOI: 10.1038/s41598-020-62181-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 03/10/2020] [Indexed: 12/20/2022] Open
Abstract
Formation of polymorphic amyloid fibrils is a common feature in neurodegenerative diseases involving protein aggregation. In Alzheimer’s disease, different fibril structures may be associated with different clinical sub-types. Structural basis of fibril polymorphism is thus important for understanding the role of amyloid fibrils in the pathogenesis and progression of these diseases. Here we studied two types of Aβ42 fibrils prepared under quiescent and agitated conditions. Quiescent Aβ42 fibrils adopt a long and twisted morphology, while agitated fibrils are short and straight, forming large bundles via lateral association. EPR studies of these two types of Aβ42 fibrils show that the secondary structure is similar in both fibril polymorphs. At the same time, agitated Aβ42 fibrils show stronger interactions between spin labels across the full range of the Aβ42 sequence, suggesting a more tightly packed structure. Our data suggest that cross-strand side chain packing interactions within the same β-sheet may play a critical role in the formation of polymorphic fibrils.
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Wang J, Park G, Lee YK, Nguyen M, San Fung T, Lin TY, Hsu F, Guo Z. Spin Label Scanning Reveals Likely Locations of β-Strands in the Amyloid Fibrils of the Ure2 Prion Domain. ACS OMEGA 2020; 5:5984-5993. [PMID: 32226879 PMCID: PMC7098000 DOI: 10.1021/acsomega.9b04358] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 02/28/2020] [Indexed: 06/10/2023]
Abstract
In yeast, the formation of Ure2 fibrils underlies the prion state [URE3], in which the yeast loses the ability to distinguish good nitrogen sources from bad ones. The Ure2 prion domain is both necessary and sufficient for the formation of amyloid fibrils. Understanding the structure of Ure2 fibrils is important for understanding the propagation not only of the [URE3] prion but also of other yeast prions whose prion domains share similar features, such as the enrichment of asparagine and glutamine residues. Here, we report a structural study of the amyloid fibrils formed by the Ure2 prion domain using site-directed spin labeling and electron paramagnetic resonance (EPR) spectroscopy. We completed a spin label scanning of all the residue positions between 2 and 80 of the Ure2 prion domain. The EPR data show that the Ure2 fibril core consists of residues 8-68 and adopts a parallel in-register β-sheet structure. Most of the residues show strong spin-exchange interactions, suggesting that there are only short turns and no long loops in the fibril core. Based on the strength of spin-exchange interactions, we determined the likely locations of the β-strands. EPR data also show that the C-terminal region of the Ure2 prion domain is more disordered than the N-terminal region. The roles of hydrophobic and charged residues are analyzed. Overall, the structure of Ure2 fibrils appears to involve a balance of stabilizing interactions, such as asparagine ladders, and destabilizing interactions, such as stacking of charged residues.
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Blodgett KN, Fischer JL, Lee J, Choi SH, Zwier TS. Conformation-Specific Spectroscopy of Asparagine-Containing Peptides: Influence of Single and Adjacent Asn Residues on Inherent Conformational Preferences. J Phys Chem A 2018; 122:8762-8775. [PMID: 30343572 DOI: 10.1021/acs.jpca.8b08418] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Karl N. Blodgett
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, United States
| | - Joshua L. Fischer
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, United States
| | - Jaeyeon Lee
- Department of Chemistry, Yonsei University, Seoul 03722, Korea
| | - Soo Hyuk Choi
- Department of Chemistry, Yonsei University, Seoul 03722, Korea
| | - Timothy S. Zwier
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, United States
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Schmuck B, Gudmundsson M, Blomqvist J, Hansson H, Härd T, Sandgren M. Production of Ready-To-Use Functionalized Sup35 Nanofibrils Secreted by Komagataella pastoris. ACS NANO 2018; 12:9363-9371. [PMID: 30207696 DOI: 10.1021/acsnano.8b04450] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Amyloid nanofibrils are excellent scaffolds for designable materials that can be endowed with biotechnologically relevant functions. However, most of all excellent ideas and concepts that have been reported in the literature might never see real-world implementation in biotechnological applications. One bottleneck is the large-scale production of these materials. In this paper, we present an attempt to create a generic and scalable platform for producing ready-to-use functionalized nanofibrils directly from a eukaryotic organism. As a model material, we assembled Sup35(1-61) amyloid nanofibrils from Saccharomyces cerevisiae decorated with the Z-domain dimer, which has a high affinity toward antibody molecules. To this end, Komagataella pastoris was engineered by inserting gene copies of Sup35(1-61) and the protein chimera Sup35(1-61)-ZZ into the genome. This strain has the capability to constantly secrete amyloidogenic proteins into the extracellular medium, where the mature functionalized fibrils form, with a production yield of 35 mg/L culture. Another striking feature of this strategy is that the separation of the fibril material from the cells requires only centrifugation and resuspension in saline water. The fast production rates, minimal hands-on time, and high stability of the assembled material are some highlights that make the direct assembly of functionalized fibrils in the extracellular medium an alternative to production methods that are not suitable for large-scale production of designed amyloids.
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Affiliation(s)
- Benjamin Schmuck
- Department of Molecular Sciences , Swedish University of Agricultural Sciences , 756 51 Uppsala , Sweden
| | - Mikael Gudmundsson
- Department of Molecular Sciences , Swedish University of Agricultural Sciences , 756 51 Uppsala , Sweden
| | - Johanna Blomqvist
- Department of Molecular Sciences , Swedish University of Agricultural Sciences , 756 51 Uppsala , Sweden
| | - Henrik Hansson
- Department of Molecular Sciences , Swedish University of Agricultural Sciences , 756 51 Uppsala , Sweden
| | - Torleif Härd
- Department of Molecular Sciences , Swedish University of Agricultural Sciences , 756 51 Uppsala , Sweden
| | - Mats Sandgren
- Department of Molecular Sciences , Swedish University of Agricultural Sciences , 756 51 Uppsala , Sweden
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12
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Schmuck B, Sandgren M, Härd T. A fine-tuned composition of protein nanofibrils yields an upgraded functionality of displayed antibody binding domains. Biotechnol J 2017; 12. [DOI: 10.1002/biot.201600672] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 03/02/2017] [Accepted: 03/31/2017] [Indexed: 01/18/2023]
Affiliation(s)
- Benjamin Schmuck
- Department of Molecular Sciences; Swedish University of Agricultural Sciences; Uppsala Sweden
| | - Mats Sandgren
- Department of Molecular Sciences; Swedish University of Agricultural Sciences; Uppsala Sweden
| | - Torleif Härd
- Department of Molecular Sciences; Swedish University of Agricultural Sciences; Uppsala Sweden
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13
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Xue C, Lin TY, Chang D, Guo Z. Thioflavin T as an amyloid dye: fibril quantification, optimal concentration and effect on aggregation. ROYAL SOCIETY OPEN SCIENCE 2017. [PMID: 28280572 DOI: 10.5061/dryad.b8c4r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Formation of amyloid fibrils underlies a wide range of human disorders, including Alzheimer's and prion diseases. The amyloid fibrils can be readily detected thanks to thioflavin T (ThT), a small molecule that gives strong fluorescence upon binding to amyloids. Using the amyloid fibrils of Aβ40 and Aβ42 involved in Alzheimer's disease, and of yeast prion protein Ure2, here we study three aspects of ThT binding to amyloids: quantification of amyloid fibrils using ThT, the optimal ThT concentration for monitoring amyloid formation and the effect of ThT on aggregation kinetics. We show that ThT fluorescence correlates linearly with amyloid concentration over ThT concentrations ranging from 0.2 to 500 µM. At a given amyloid concentration, the plot of ThT fluorescence versus ThT concentration exhibits a bell-shaped curve. The maximal fluorescence signal depends mostly on the total ThT concentration, rather than amyloid to ThT ratio. For the three proteins investigated, the maximal fluorescence is observed at ThT concentrations of 20-50 µM. Aggregation kinetics experiments in the presence of different ThT concentrations show that ThT has little effect on aggregation at concentrations of 20 µM or lower. ThT at concentrations of 50 µM or more could affect the shape of the aggregation curves, but this effect is protein-dependent and not universal.
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Affiliation(s)
- Christine Xue
- Department of Neurology, Brain Research Institute, Molecular Biology Institute , University of California , Los Angeles, CA 90095 , USA
| | - Tiffany Yuwen Lin
- Department of Neurology, Brain Research Institute, Molecular Biology Institute , University of California , Los Angeles, CA 90095 , USA
| | - Dennis Chang
- Department of Neurology, Brain Research Institute, Molecular Biology Institute , University of California , Los Angeles, CA 90095 , USA
| | - Zhefeng Guo
- Department of Neurology, Brain Research Institute, Molecular Biology Institute , University of California , Los Angeles, CA 90095 , USA
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14
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Xue C, Lin TY, Chang D, Guo Z. Thioflavin T as an amyloid dye: fibril quantification, optimal concentration and effect on aggregation. ROYAL SOCIETY OPEN SCIENCE 2017; 4:160696. [PMID: 28280572 PMCID: PMC5319338 DOI: 10.1098/rsos.160696] [Citation(s) in RCA: 408] [Impact Index Per Article: 58.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 11/28/2016] [Indexed: 05/18/2023]
Abstract
Formation of amyloid fibrils underlies a wide range of human disorders, including Alzheimer's and prion diseases. The amyloid fibrils can be readily detected thanks to thioflavin T (ThT), a small molecule that gives strong fluorescence upon binding to amyloids. Using the amyloid fibrils of Aβ40 and Aβ42 involved in Alzheimer's disease, and of yeast prion protein Ure2, here we study three aspects of ThT binding to amyloids: quantification of amyloid fibrils using ThT, the optimal ThT concentration for monitoring amyloid formation and the effect of ThT on aggregation kinetics. We show that ThT fluorescence correlates linearly with amyloid concentration over ThT concentrations ranging from 0.2 to 500 µM. At a given amyloid concentration, the plot of ThT fluorescence versus ThT concentration exhibits a bell-shaped curve. The maximal fluorescence signal depends mostly on the total ThT concentration, rather than amyloid to ThT ratio. For the three proteins investigated, the maximal fluorescence is observed at ThT concentrations of 20-50 µM. Aggregation kinetics experiments in the presence of different ThT concentrations show that ThT has little effect on aggregation at concentrations of 20 µM or lower. ThT at concentrations of 50 µM or more could affect the shape of the aggregation curves, but this effect is protein-dependent and not universal.
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Affiliation(s)
| | | | | | - Zhefeng Guo
- Author for correspondence: Zhefeng Guo e-mail:
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15
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Gu L, Tran J, Jiang L, Guo Z. A new structural model of Alzheimer's Aβ42 fibrils based on electron paramagnetic resonance data and Rosetta modeling. J Struct Biol 2016; 194:61-7. [PMID: 26827680 DOI: 10.1016/j.jsb.2016.01.013] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 01/24/2016] [Accepted: 01/27/2016] [Indexed: 10/22/2022]
Abstract
Brain deposition of Aβ in the form of amyloid plaques is a pathological hallmark of Alzheimer's disease. There are two major species of Aβ in the brain: Aβ42 and Aβ40. Although Aβ40 is several-fold more abundant than Aβ42 in soluble form, Aβ42 is the major component of amyloid plaques. Structural knowledge of Aβ42 fibrils is important both for understanding the process of Aβ aggregation and for designing fibril-targeting drugs. Here we report site-specific structural information of Aβ42 fibrils at 22 residue positions based on electron paramagnetic resonance data. In combination with structure prediction program Rosetta, we modeled Aβ42 fibril structure at atomic resolution. Our Aβ42 fibril model consists of four parallel in-register β-sheets: βN (residues ∼7-13), β1 (residues ∼17-20), β2 (residues ∼32-36), and βC (residues 39-41). The region of β1-loop-β2 in Aβ42 fibrils adopts similar structure as that in Aβ40 fibrils. This is consistent with our cross seeding data that Aβ42 fibril seeds shortened the lag phase of Aβ40 fibrillization. On the other hand, Aβ42 fibrils contain a C-terminal β-arc-β motif with a special turn, termed "arc", at residues 37-38, which is absent in Aβ40 fibrils. Our results can explain both the higher aggregation propensity of Aβ42 and the importance of Aβ42 to Aβ40 ratio in the pathogenesis of Alzheimer's disease.
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Affiliation(s)
- Lei Gu
- Department of Neurology, Brain Research Institute, Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA
| | - Joyce Tran
- Department of Neurology, Brain Research Institute, Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA
| | - Lin Jiang
- Department of Neurology, Brain Research Institute, Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA
| | - Zhefeng Guo
- Department of Neurology, Brain Research Institute, Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA.
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16
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Wickner RB, Edskes HK, Gorkovskiy A, Bezsonov EE, Stroobant EE. Yeast and Fungal Prions: Amyloid-Handling Systems, Amyloid Structure, and Prion Biology. ADVANCES IN GENETICS 2016; 93:191-236. [PMID: 26915272 DOI: 10.1016/bs.adgen.2015.12.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Yeast prions (infectious proteins) were discovered by their outré genetic properties and have become important models for an array of human prion and amyloid diseases. A single prion protein can become any of many distinct amyloid forms (called prion variants or strains), each of which is self-propagating, but with different biological properties (eg, lethal vs mild). The folded in-register parallel β sheet architecture of the yeast prion amyloids naturally suggests a mechanism by which prion variant information can be faithfully transmitted for many generations. The yeast prions rely on cellular chaperones for their propagation, but can be cured by various chaperone imbalances. The Btn2/Cur1 system normally cures most variants of the [URE3] prion that arise. Although most variants of the [PSI+] and [URE3] prions are toxic or lethal, some are mild in their effects. Even the most mild forms of these prions are rare in the wild, indicating that they too are detrimental to yeast. The beneficial [Het-s] prion of Podospora anserina poses an important contrast in its structure, biology, and evolution to the yeast prions characterized thus far.
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Affiliation(s)
- R B Wickner
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - H K Edskes
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - A Gorkovskiy
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - E E Bezsonov
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - E E Stroobant
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
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17
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Meyer V, Margittai M. Spin Labeling and Characterization of Tau Fibrils Using Electron Paramagnetic Resonance (EPR). Methods Mol Biol 2016; 1345:185-199. [PMID: 26453213 DOI: 10.1007/978-1-4939-2978-8_12] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Template-assisted propagation of Tau fibrils is essential for the spreading of Tau pathology in Alzheimer's disease. In this process, small seeds of fibrils recruit Tau monomers onto their ends. The physical properties of the fibrils play an important role in their propagation. Here, we describe two different electron paramagnetic resonance (EPR) techniques that have provided crucial insights into the structure of Tau fibrils. Both techniques rely on the site-directed introduction of one or two spin labels into the protein monomer. Continuous-wave (CW) EPR provides information on which amino acid residues are contained in the fibril core and how they are stacked along the long fibril axis. Double electron-electron resonance (DEER) determines distances between two spin labels within a single protein and hence provides insights into their spatial arrangement in the fibril cross section. Because of the long distance range accessible to DEER (~2-5 nm) populations of distinct fibril conformers can be differentiated.
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Affiliation(s)
- Virginia Meyer
- Department of Chemistry and Biochemistry, University of Denver, 2190 East Iliff Ave, Denver, CO, 80208, USA
| | - Martin Margittai
- Department of Chemistry and Biochemistry, University of Denver, 2190 East Iliff Ave, Denver, CO, 80208, USA.
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18
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Abstract
A prion is an infectious protein horizontally transmitting a disease or trait without a required nucleic acid. Yeast and fungal prions are nonchromosomal genes composed of protein, generally an altered form of a protein that catalyzes the same alteration of the protein. Yeast prions are thus transmitted both vertically (as genes composed of protein) and horizontally (as infectious proteins, or prions). Formation of amyloids (linear ordered β-sheet-rich protein aggregates with β-strands perpendicular to the long axis of the filament) underlies most yeast and fungal prions, and a single prion protein can have any of several distinct self-propagating amyloid forms with different biological properties (prion variants). Here we review the mechanism of faithful templating of protein conformation, the biological roles of these prions, and their interactions with cellular chaperones, the Btn2 and Cur1 aggregate-handling systems, and other cellular factors governing prion generation and propagation. Human amyloidoses include the PrP-based prion conditions and many other, more common amyloid-based diseases, several of which show prion-like features. Yeast prions increasingly are serving as models for the understanding and treatment of many mammalian amyloidoses. Patients with different clinical pictures of the same amyloidosis may be the equivalent of yeasts with different prion variants.
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19
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Abstract
A prion is an infectious protein horizontally transmitting a disease or trait without a required nucleic acid. Yeast and fungal prions are nonchromosomal genes composed of protein, generally an altered form of a protein that catalyzes the same alteration of the protein. Yeast prions are thus transmitted both vertically (as genes composed of protein) and horizontally (as infectious proteins, or prions). Formation of amyloids (linear ordered β-sheet-rich protein aggregates with β-strands perpendicular to the long axis of the filament) underlies most yeast and fungal prions, and a single prion protein can have any of several distinct self-propagating amyloid forms with different biological properties (prion variants). Here we review the mechanism of faithful templating of protein conformation, the biological roles of these prions, and their interactions with cellular chaperones, the Btn2 and Cur1 aggregate-handling systems, and other cellular factors governing prion generation and propagation. Human amyloidoses include the PrP-based prion conditions and many other, more common amyloid-based diseases, several of which show prion-like features. Yeast prions increasingly are serving as models for the understanding and treatment of many mammalian amyloidoses. Patients with different clinical pictures of the same amyloidosis may be the equivalent of yeasts with different prion variants.
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20
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Locating folds of the in-register parallel β-sheet of the Sup35p prion domain infectious amyloid. Proc Natl Acad Sci U S A 2014; 111:E4615-22. [PMID: 25313080 DOI: 10.1073/pnas.1417974111] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The [PSI+] prion is a self-propagating amyloid of the translation termination factor, Sup35p, of Saccharomyces cerevisiae. The N-terminal 253 residues (NM) of this 685-residue protein normally function in regulating mRNA turnover but spontaneously form infectious amyloid in vitro. We converted the three Ile residues in Sup35NM to Leu and then replaced 16 single residues with Ile, one by one, and prepared Ile-1-(13)C amyloid of each mutant, seeding with amyloid formed by the reference sequence Sup35NM. Using solid-state NMR, we showed that 10 of the residues examined, including six between residues 30 and 90, showed the ∼0.5-nm distance between labels diagnostic of the in-register parallel amyloid architecture. The five scattered N domain residues with wider spacing may be in turns or loops; one is a control at the C terminus of M. All mutants, except Q56I, showed little or no [PSI+] transmission barrier from the reference sequence, suggesting that they could assume a similar amyloid architecture in vitro when seeded with filaments of reference sequence Sup35NM. Infection of yeast cells expressing the reference SUP35 gene sequence with amyloid of several mutants produced [PSI+] transfectants with similar efficiency as did reference sequence Sup35NM amyloid. Our work provides a stringent demonstration that the Sup35 prion domain has the folded in-register parallel β-sheet architecture and suggests common locations of the folds. This architecture naturally suggests a mechanism of inheritance of conformation, the central mystery of prions.
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21
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Gu L, Liu C, Stroud JC, Ngo S, Jiang L, Guo Z. Antiparallel triple-strand architecture for prefibrillar Aβ42 oligomers. J Biol Chem 2014; 289:27300-27313. [PMID: 25118290 PMCID: PMC4175361 DOI: 10.1074/jbc.m114.569004] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Revised: 08/05/2014] [Indexed: 12/21/2022] Open
Abstract
Aβ42 oligomers play key roles in the pathogenesis of Alzheimer disease, but their structures remain elusive partly due to their transient nature. Here, we show that Aβ42 in a fusion construct can be trapped in a stable oligomer state, which recapitulates characteristics of prefibrillar Aβ42 oligomers and enables us to establish their detailed structures. Site-directed spin labeling and electron paramagnetic resonance studies provide structural restraints in terms of side chain mobility and intermolecular distances at all 42 residue positions. Using these restraints and other biophysical data, we present a novel atomic-level oligomer model. In our model, each Aβ42 protein forms a single β-sheet with three β-strands in an antiparallel arrangement. Each β-sheet consists of four Aβ42 molecules in a head-to-tail arrangement. Four β-sheets are packed together in a face-to-back fashion. The stacking of identical segments between different β-sheets within an oligomer suggests that prefibrillar oligomers may interconvert with fibrils via strand rotation, wherein β-strands undergo an ∼90° rotation along the strand direction. This work provides insights into rational design of therapeutics targeting the process of interconversion between toxic oligomers and non-toxic fibrils.
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Affiliation(s)
- Lei Gu
- Department of Neurology, Brain Research Institute, Molecular Biology Institute, UCLA-DOE Institute for Genomics and Proteomics, University of California, Los Angeles, California 90095
| | - Cong Liu
- Departments of Chemistry and Biochemistry and Biological Chemistry, Howard Hughes Medical Institute, UCLA-DOE Institute for Genomics and Proteomics, University of California, Los Angeles, California 90095,; Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, 200032, China, and
| | - James C Stroud
- Department of Chemistry and Chemical Biology, Center for Biomedical Engineering, University of New Mexico, Albuquerque, New Mexico 87131
| | - Sam Ngo
- Department of Neurology, Brain Research Institute, Molecular Biology Institute, UCLA-DOE Institute for Genomics and Proteomics, University of California, Los Angeles, California 90095
| | - Lin Jiang
- Departments of Chemistry and Biochemistry and Biological Chemistry, Howard Hughes Medical Institute, UCLA-DOE Institute for Genomics and Proteomics, University of California, Los Angeles, California 90095
| | - Zhefeng Guo
- Department of Neurology, Brain Research Institute, Molecular Biology Institute, UCLA-DOE Institute for Genomics and Proteomics, University of California, Los Angeles, California 90095.
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22
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The BAG homology domain of Snl1 cures yeast prion [URE3] through regulation of Hsp70 chaperones. G3-GENES GENOMES GENETICS 2014; 4:461-70. [PMID: 24408033 PMCID: PMC3962485 DOI: 10.1534/g3.113.009993] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The BAG family of proteins is evolutionarily conserved from yeast to humans and plants. In animals and plants, the BAG family possesses multiple members with overlapping and distinct functions that regulate many cellular processes, such as signaling, protein degradation, and stress response. The only BAG domain protein in Saccharomyces cerevisiae is Snl1, which is anchored to the endoplasmic reticulum through an amino-terminal transmembrane region. Snl1 is the only known membrane-associated nucleotide exchange factor for 70-kilodalton heat shock protein (Hsp70), and thus its role in regulating cytosolic Hsp70 functions is not clear. Here, we examine whether Snl1 regulates Hsp70 activity in the propagation of stable prion-like protein aggregates. We show that unlike other nucleotide exchange factors, Snl1 is not required for propagation of yeast prions [URE3] and [PSI+]. Overexpressing Snl1 derivative consisting of only the BAG domain (Snl1-S) cures [URE3]; however, elevated levels of the entire cytosolic domain of Snl1 (Snl1-M), which has nine additional amino-terminal residues, has no effect. Substituting the three lysine residues in this region of Snl1-M with alanine restores ability to cure [URE3]. [PSI+] is unaffected by overproduction of either Snl1-S or Snl1-M. The Snl1-S mutant engineered with weaker affinity to Hsp70 does not cure [URE3], indicating that curing of [URE3] by Snl1-S requires Hsp70. Our data suggest that Snl1 anchoring to endoplasmic reticulum or nuclear membrane restricts its ability to modulate cytosolic activities of Hsp70 proteins. Furthermore, the short amino-terminal extension of the BAG domain profoundly affects its function.
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23
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Wickner RB, Edskes HK, Bateman DA, Kelly AC, Gorkovskiy A, Dayani Y, Zhou A. Amyloids and yeast prion biology. Biochemistry 2013; 52:1514-27. [PMID: 23379365 DOI: 10.1021/bi301686a] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The prions (infectious proteins) of Saccharomyces cerevisiae are proteins acting as genes, by templating their conformation from one molecule to another in analogy to DNA templating its sequence. Most yeast prions are amyloid forms of normally soluble proteins, and a single protein sequence can have any of several self-propagating forms (called prion strains or variants), analogous to the different possible alleles of a DNA gene. A central issue in prion biology is the structural basis of this conformational templating process. The in-register parallel β sheet structure found for several infectious yeast prion amyloids naturally suggests an explanation for this conformational templating. While most prions are plainly diseases, the [Het-s] prion of Podospora anserina may be a functional amyloid, with important structural implications. Yeast prions are important models for human amyloid diseases in general, particularly because new evidence is showing infectious aspects of several human amyloidoses not previously classified as prions. We also review studies of the roles of chaperones, aggregate-collecting proteins, and other cellular components using yeast that have led the way in improving the understanding of similar processes that must be operating in many human amyloidoses.
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Affiliation(s)
- Reed B Wickner
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0830, USA.
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24
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Ngo S, Chiang V, Ho E, Le L, Guo Z. Prion domain of yeast Ure2 protein adopts a completely disordered structure: a solid-support EPR study. PLoS One 2012; 7:e47248. [PMID: 23077577 PMCID: PMC3473064 DOI: 10.1371/journal.pone.0047248] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Accepted: 09/12/2012] [Indexed: 12/03/2022] Open
Abstract
Amyloid fibril formation is associated with a range of neurodegenerative diseases in humans, including Alzheimer’s, Parkinson’s, and prion diseases. In yeast, amyloid underlies several non-Mendelian phenotypes referred to as yeast prions. Mechanism of amyloid formation is critical for a complete understanding of the yeast prion phenomenon and human amyloid-related diseases. Ure2 protein is the basis of yeast prion [URE3]. The Ure2p prion domain is largely disordered. Residual structures, if any, in the disordered region may play an important role in the aggregation process. Studies of Ure2p prion domain are complicated by its high aggregation propensity, which results in a mixture of monomer and aggregates in solution. Previously we have developed a solid-support electron paramagnetic resonance (EPR) approach to address this problem and have identified a structured state for the Alzheimer’s amyloid-β monomer. Here we use solid-support EPR to study the structure of Ure2p prion domain. EPR spectra of Ure2p prion domain with spin labels at every fifth residue from position 10 to position 75 show similar residue mobility profile for denaturing and native buffers after accounting for the effect of solution viscosity. These results suggest that Ure2p prion domain adopts a completely disordered structure in the native buffer. A completely disordered Ure2p prion domain implies that the amyloid formation of Ure2p, and likely other Q/N-rich yeast prion proteins, is primarily driven by inter-molecular interactions.
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Affiliation(s)
- Sam Ngo
- Department of Neurology, Brain Research Institute, Molecular Biology Institute, University of California Los Angeles, Los Angeles, California, United States of America
| | - Vicky Chiang
- Department of Neurology, Brain Research Institute, Molecular Biology Institute, University of California Los Angeles, Los Angeles, California, United States of America
| | - Elaine Ho
- Department of Neurology, Brain Research Institute, Molecular Biology Institute, University of California Los Angeles, Los Angeles, California, United States of America
| | - Linh Le
- Department of Neurology, Brain Research Institute, Molecular Biology Institute, University of California Los Angeles, Los Angeles, California, United States of America
| | - Zhefeng Guo
- Department of Neurology, Brain Research Institute, Molecular Biology Institute, University of California Los Angeles, Los Angeles, California, United States of America
- * E-mail:
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25
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Abstract
Formation of senile plaques containing amyloid fibrils of Aβ (amyloid β-peptide) is a pathological hallmark of Alzheimer's disease. Unlike globular proteins, which fold into unique structures, the fibrils of Aβ and other amyloid proteins often contain multiple polymorphs. Polymorphism of amyloid fibrils leads to different toxicity in amyloid diseases and may be the basis for prion strains, but the structural origin for fibril polymorphism is still elusive. In the present study we investigate the structural origin of two major fibril polymorphs of Aβ40: an untwisted polymorph formed under agitated conditions and a twisted polymorph formed under quiescent conditions. Using electron paramagnetic resonance spectroscopy, we studied the inter-strand side-chain interactions at 14 spin-labelled positions in the Aβ40 sequence. The results of the present study show that the agitated fibrils have stronger inter-strand spin–spin interactions at most of the residue positions investigated. The two hydrophobic regions at residues 17–20 and 31–36 have the strongest interactions in agitated fibrils. Distance estimates on the basis of the spin exchange frequencies suggest that inter-strand distances at residues 17, 20, 32, 34 and 36 in agitated fibrils are approximately 0.2 Å (1 Å=0.1 nm) closer than in quiescent fibrils. We propose that the strength of inter-strand side-chain interactions determines the degree of β-sheet twist, which then leads to the different association patterns between different cross β-units and thus distinct fibril morphologies. Therefore the inter-strand side-chain interaction may be a structural origin for fibril polymorphism in Aβ and other amyloid proteins.
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26
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Ngo S, Chiang V, Guo Z. Quantitative analysis of spin exchange interactions to identify β strand and turn regions in Ure2 prion domain fibrils with site-directed spin labeling. J Struct Biol 2012; 180:374-81. [PMID: 22967940 DOI: 10.1016/j.jsb.2012.08.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Revised: 08/23/2012] [Accepted: 08/24/2012] [Indexed: 12/21/2022]
Abstract
Amyloid formation is associated with a range of debilitating human disorders including Alzheimer's and prion diseases. The amyloid structure is essential for understanding the role of amyloids in these diseases. Amyloid formation of Ure2 protein underlies the yeast prion [URE3]. Here we use site-directed spin labeling and electron paramagnetic resonance (EPR) spectroscopy to investigate the structure of amyloid fibrils formed by the Ure2 prion domain. The Ure2 prion domain under study contains a Sup35M domain at C-terminus as a solubilization element. We introduced spin labels at every residue from positions 2-15, and every 5th residue from positions 20-80 in Ure2 prion domain. EPR spectra at most labeling sites show strong spin exchange interactions, suggesting a parallel in-register β structure. With quantitative analysis of spin exchange interactions, we show that residues 8-12 form the first β strand, followed by a turn at residues 13-14, and then the second β strand from residue 15 to at least residue 20. Comparison of the spin exchange frequency for the fibrils formed under quiescent and agitated conditions also revealed differences in the fibril structures. Currently there is a lack of techniques for in-depth structural studies of amyloid fibrils. Detailed structural information is obtained almost exclusively from solid-state NMR. The identification of β-strand and turn regions in this work suggests that quantitative analysis of spin exchange interactions in spin-labeled amyloid fibrils is a powerful approach for identifying the β-strand and turn/loop residues and for studying structural differences of different fibril polymorphs.
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Affiliation(s)
- Sam Ngo
- Department of Neurology, Brain Research Institute, Molecular Biology Institute, University of California, 710 Westwood Plaza, Los Angeles, CA 90095, USA
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27
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Abstract
The concept of a prion as an infectious self-propagating protein isoform was initially proposed to explain certain mammalian diseases. It is now clear that yeast also has heritable elements transmitted via protein. Indeed, the "protein only" model of prion transmission was first proven using a yeast prion. Typically, known prions are ordered cross-β aggregates (amyloids). Recently, there has been an explosion in the number of recognized prions in yeast. Yeast continues to lead the way in understanding cellular control of prion propagation, prion structure, mechanisms of de novo prion formation, specificity of prion transmission, and the biological roles of prions. This review summarizes what has been learned from yeast prions.
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Affiliation(s)
- Susan W Liebman
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Nevada 89557, USA.
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28
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Lyubchenko YL, Krasnoslobodtsev AV, Luca S. Fibrillogenesis of huntingtin and other glutamine containing proteins. Subcell Biochem 2012; 65:225-51. [PMID: 23225006 PMCID: PMC4226413 DOI: 10.1007/978-94-007-5416-4_10] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
This chapter focuses on the aggregation of glutamine containing peptides and proteins with an emphasis on huntingtin protein, whose aggregation leads to the development of Huntington's disease. The kinetics that leads to the formation of amyloids, the structure of aggregates of various types and the morphological mechanical properties of amyloid fibrils are described. The kinetics of amyloid fibril formation has been proposed to follow a nucleation dependent polymerization model, dependent upon the size of the nucleus. This model and the effect of the polyglutamine length on the nucleus size are reviewed. Aggregate structure is characterized at two different levels. The atomic-scale resolution structure of fibrillar and crystalline aggregates of polyglutamine containing proteins and peptides was determined by X-ray crystallography and solid-state nuclear magnetic resonance (NMR). The chapter outlines the results obtained by both these techniques. Atomic force microscopy (AFM) was instrumental in elucidating the morphology of fibrils, their organization and assembly. The chapter also discusses the high stability of amyloid fibrils, including their mechanical properties as revealed by AFM.
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Affiliation(s)
- Yuri L. Lyubchenko
- Department of Pharmaceutical Sciences, Nanoimaging Core Facility College of Pharmacy, University of Nebraska Medical Center, COP 1012, 986025 Nebraska Medical Center, Omaha, NE 68198-6025, USA
| | - Alexey V. Krasnoslobodtsev
- Department of Pharmaceutical Sciences, Nanoimaging Core Facility College of Pharmacy, University of Nebraska Medical Center, COP 1012, 986025 Nebraska Medical Center, Omaha, NE 68198-6025, USA
| | - Sorin Luca
- Department of Pharmaceutical Sciences, Nanoimaging Core Facility College of Pharmacy, University of Nebraska Medical Center, COP 1012, 986025 Nebraska Medical Center, Omaha, NE 68198-6025, USA
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