1
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do Amaral MJ, Freire MHO, Almeida MS, Pinheiro AS, Cordeiro Y. Phase separation of the mammalian prion protein: physiological and pathological perspectives. J Neurochem 2022. [PMID: 35149997 DOI: 10.1111/jnc.15586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 01/24/2022] [Accepted: 01/31/2022] [Indexed: 11/27/2022]
Abstract
Abnormal phase transitions have been implicated in the occurrence of proteinopathies. Disordered proteins with nucleic acid binding ability drive the formation of reversible micron-sized condensates capable of controlling nucleic acid processing/transport. This mechanism, achieved via liquid-liquid phase separation (LLPS), underlies the formation of long-studied membraneless organelles (e.g., nucleolus) and various transient condensates formed by driver proteins. The prion protein (PrP) is not a classical nucleic acid-binding protein. However, it binds nucleic acids with high affinity, undergoes nucleocytoplasmic shuttling, contains a long intrinsically disordered region rich in glycines and evenly spaced aromatic residues, among other biochemical/biophysical properties of bona fide drivers of phase transitions. Because of this, our group and others have characterized LLPS of recombinant PrP. In vitro phase separation of PrP is modulated by nucleic acid aptamers, and, depending on the aptamer conformation, the liquid droplets evolve to solid-like species. Herein we discuss recent studies and previous evidence supporting PrP phase transitions. We focus on the central role of LLPS related to PrP physiology and pathology, with a special emphasis on the interaction of PrP with different ligands, such as proteins and nucleic acids, which can play a role in prion disease pathogenesis. Finally, we comment on therapeutic strategies directed at the nonfunctional phase separation that could potentially tackle prion diseases or other protein misfolding disorders.
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Affiliation(s)
- Mariana J do Amaral
- Faculty of Pharmacy, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | | | | | - Anderson S Pinheiro
- Department of Biochemistry, Institute of Chemistry, Rio de Janeiro, RJ, Brazil
| | - Yraima Cordeiro
- Faculty of Pharmacy, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
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2
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Panes JD, Saavedra P, Pineda B, Escobar K, Cuevas ME, Moraga-Cid G, Fuentealba J, Rivas CI, Rezaei H, Muñoz-Montesino C. PrP C as a Transducer of Physiological and Pathological Signals. Front Mol Neurosci 2021; 14:762918. [PMID: 34880726 PMCID: PMC8648500 DOI: 10.3389/fnmol.2021.762918] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 10/18/2021] [Indexed: 11/13/2022] Open
Abstract
After the discovery of prion phenomenon, the physiological role of the cellular prion protein (PrP C ) remained elusive. In the past decades, molecular and cellular analysis has shed some light regarding interactions and functions of PrP C in health and disease. PrP C , which is located mainly at the plasma membrane of neuronal cells attached by a glycosylphosphatidylinositol (GPI) anchor, can act as a receptor or transducer from external signaling. Although the precise role of PrP C remains elusive, a variety of functions have been proposed for this protein, namely, neuronal excitability and viability. Although many issues must be solved to clearly define the role of PrP C , its connection to the central nervous system (CNS) and to several misfolding-associated diseases makes PrP C an interesting pharmacological target. In a physiological context, several reports have proposed that PrP C modulates synaptic transmission, interacting with various proteins, namely, ion pumps, channels, and metabotropic receptors. PrP C has also been implicated in the pathophysiological cell signaling induced by β-amyloid peptide that leads to synaptic dysfunction in the context of Alzheimer's disease (AD), as a mediator of Aβ-induced cell toxicity. Additionally, it has been implicated in other proteinopathies as well. In this review, we aimed to analyze the role of PrP C as a transducer of physiological and pathological signaling.
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Affiliation(s)
- Jessica D Panes
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Paulina Saavedra
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile.,Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Benjamin Pineda
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Kathleen Escobar
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile.,Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Magdalena E Cuevas
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Gustavo Moraga-Cid
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Jorge Fuentealba
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Coralia I Rivas
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Human Rezaei
- Virologie et Immunologie Moléculaires (VIM), Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (INRAE), Jouy-en-Josas, France.,Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Versailles, France.,Université Paris-Saclay, Jouy-en-Josas, France
| | - Carola Muñoz-Montesino
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
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3
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Novel quaternary structures of the human prion protein globular domain. Biochimie 2021; 191:118-125. [PMID: 34517052 DOI: 10.1016/j.biochi.2021.09.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 08/30/2021] [Accepted: 09/07/2021] [Indexed: 11/22/2022]
Abstract
Prion disease is caused by the misfolding of the cellular prion protein, PrPC, into a self-templating conformer, PrPSc. Nuclear magnetic resonance (NMR) and X-ray crystallography revealed the 3D structure of the globular domain of PrPC and the possibility of its dimerization via an interchain disulfide bridge that forms due to domain swap or by non-covalent association of two monomers. On the contrary, PrPSc is composed by a complex and heterogeneous ensemble of poorly defined conformations and quaternary arrangements that are related to different patterns of neurotoxicity. Targeting PrPC with molecules that stabilize the native conformation of its globular domain emerged as a promising approach to develop anti-prion therapies. One of the advantages of this approach is employing structure-based drug discovery methods to PrPC. Thus, it is essential to expand our structural knowledge about PrPC as much as possible to aid such drug discovery efforts. In this work, we report a crystallographic structure of the globular domain of human PrPC that shows a novel dimeric form and a novel oligomeric arrangement. We use molecular dynamics simulations to explore its structural dynamics and stability and discuss potential implications of these new quaternary structures to the conversion process.
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4
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Matos CO, Passos YM, do Amaral MJ, Macedo B, Tempone MH, Bezerra OCL, Moraes MO, Almeida MS, Weber G, Missailidis S, Silva JL, Uversky VN, Pinheiro AS, Cordeiro Y. Liquid-liquid phase separation and fibrillation of the prion protein modulated by a high-affinity DNA aptamer. FASEB J 2019; 34:365-385. [PMID: 31914616 DOI: 10.1096/fj.201901897r] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 10/09/2019] [Accepted: 10/15/2019] [Indexed: 01/17/2023]
Abstract
Structural conversion of cellular prion protein (PrPC) into scrapie PrP (PrPSc) and subsequent aggregation are key events associated with the onset of transmissible spongiform encephalopathies (TSEs). Experimental evidence supports the role of nucleic acids (NAs) in assisting this conversion. Here, we asked whether PrP undergoes liquid-liquid phase separation (LLPS) and if this process is modulated by NAs. To this end, two 25-mer DNA aptamers, A1 and A2, were selected against the globular domain of recombinant murine PrP (rPrP90-231) using SELEX methodology. Multiparametric structural analysis of these aptamers revealed that A1 adopts a hairpin conformation. Aptamer binding caused partial unfolding of rPrP90-231 and modulated its ability to undergo LLPS and fibrillate. In fact, although free rPrP90-231 phase separated into large droplets, aptamer binding increased the number of droplets but noticeably reduced their size. Strikingly, a modified A1 aptamer that does not adopt a hairpin structure induced formation of amyloid fibrils on the surface of the droplets. We show here that PrP undergoes LLPS, and that the PrP interaction with NAs modulates phase separation and promotes PrP fibrillation in a NA structure and concentration-dependent manner. These results shed new light on the roles of NAs in PrP misfolding and TSEs.
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Affiliation(s)
- Carolina O Matos
- Department of Biochemistry, Institute of Chemistry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Yulli M Passos
- Faculty of Pharmacy, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Mariana J do Amaral
- Institute of Medical Biochemistry Leopoldo de Meis, National Center for Structural Biology and Bioimaging (CENABIO), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Bruno Macedo
- Faculty of Pharmacy, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Matheus H Tempone
- Faculty of Pharmacy, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Ohanna C L Bezerra
- Leprosy Laboratory, Oswaldo Cruz Institute, Oswaldo Cruz Foundation (FIOCRUZ), Rio de Janeiro, Brazil
| | - Milton O Moraes
- Leprosy Laboratory, Oswaldo Cruz Institute, Oswaldo Cruz Foundation (FIOCRUZ), Rio de Janeiro, Brazil
| | - Marcius S Almeida
- Institute of Medical Biochemistry Leopoldo de Meis, National Center for Structural Biology and Bioimaging (CENABIO), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Gerald Weber
- Department of Physics, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Sotiris Missailidis
- Institute of Technology in Immunobiologics (Bio-Manguinhos), Oswaldo Cruz Foundation (FIOCRUZ), Rio de Janeiro, Brazil
| | - Jerson L Silva
- Institute of Medical Biochemistry Leopoldo de Meis, National Center for Structural Biology and Bioimaging (CENABIO), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Vladimir N Uversky
- Department of Molecular Medicine, USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL, USA.,Laboratory of New Methods in Biology, Institute for Biological Instrumentation, Russian Academy of Sciences, Pushchino, Russia
| | - Anderson S Pinheiro
- Department of Biochemistry, Institute of Chemistry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Yraima Cordeiro
- Faculty of Pharmacy, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
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5
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Gao Z, Shi J, Cai L, Luo M, Wong BS, Dong X, Sy MS, Li C. Prion dimer is heterogenous and is modulated by multiple negative and positive motifs. Biochem Biophys Res Commun 2018; 509:570-576. [PMID: 30600179 DOI: 10.1016/j.bbrc.2018.12.113] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 12/15/2018] [Indexed: 01/16/2023]
Abstract
The conversion of the normal prion protein (PrP) into a scrapie prion (PrPSc) is incompletely understood. Theoretically, the smallest PrP aggregate is a dimer. Human PrP contains two cysteines at positions 179 (C179) and 214 (C214) enabling disulfide bonding. Here, we report that our recombinant human PrP (r-hPrP) preparations contain 0.2-0.8% dimer, which is linked by either one or two disulfide bonds, connected by C179-C179, C214-C214, or C179-C214. Furthermore, dimerization is regulated by multiple motifs. While residues 36-42 inhibit, residues 90-125, and 195-212 promote dimerization. Mutating individual residue between 36 and 42 enhances dimerization whereas mutating the positively charged residues within 95-115, or the negatively charged residues within 195-212 prevent dimerization. Although deletion of the entire octapeptide-repeat (5OR) region prevents dimerization, mutating the histidines within the 5OR enhances dimerization. In addition, we found that two out of three brain lysates from patients with inherited prion disease had more PrP dimers than controls. Thus, PrP dimerization may contribute to prion diseases.
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Affiliation(s)
- Zhenxing Gao
- Wuhan Institute of Virology, Chinese Academy of Sciences, State Key Laboratory of Virology, 44 Xiao Hong Shan Zhong Qu, Wuhan, 430071, China; Affiliated Cancer Hospital & Institute of Guangzhou Medical University, 78 Heng Zhi Gang Road, Guangzhou, 510095, China
| | - Jing Shi
- Xiangyang Center for Disease Control and Prevention, 172 Tan Xi Road, Xiangyang, Hubei, China
| | - Lili Cai
- Wuhan Institute of Virology, Chinese Academy of Sciences, State Key Laboratory of Virology, 44 Xiao Hong Shan Zhong Qu, Wuhan, 430071, China
| | - Minhua Luo
- Wuhan Institute of Virology, Chinese Academy of Sciences, State Key Laboratory of Virology, 44 Xiao Hong Shan Zhong Qu, Wuhan, 430071, China
| | - Boon-Seng Wong
- Health and Social Sciences Cluster, Singapore Institute of Technology, Singapore
| | - Xiaoping Dong
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases (Zhejiang University), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Chang-Bai Rd 155, Beijing, 102206, China
| | - Man-Sun Sy
- Department of Pathology, School of Medicine, Case Western Reserve University, 2103 Cornell Road, Cleveland, USA
| | - Chaoyang Li
- Wuhan Institute of Virology, Chinese Academy of Sciences, State Key Laboratory of Virology, 44 Xiao Hong Shan Zhong Qu, Wuhan, 430071, China; Affiliated Cancer Hospital & Institute of Guangzhou Medical University, 78 Heng Zhi Gang Road, Guangzhou, 510095, China.
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6
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Engelke AD, Gonsberg A, Thapa S, Jung S, Ulbrich S, Seidel R, Basu S, Multhaup G, Baier M, Engelhard M, Schätzl HM, Winklhofer KF, Tatzelt J. Dimerization of the cellular prion protein inhibits propagation of scrapie prions. J Biol Chem 2018; 293:8020-8031. [PMID: 29636413 DOI: 10.1074/jbc.ra117.000990] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 04/06/2018] [Indexed: 11/06/2022] Open
Abstract
A central step in the pathogenesis of prion diseases is the conformational transition of the cellular prion protein (PrPC) into the scrapie isoform, denoted PrPSc Studies in transgenic mice have indicated that this conversion requires a direct interaction between PrPC and PrPSc; however, insights into the underlying mechanisms are still missing. Interestingly, only a subfraction of PrPC is converted in scrapie-infected cells, suggesting that not all PrPC species are suitable substrates for the conversion. On the basis of the observation that PrPC can form homodimers under physiological conditions with the internal hydrophobic domain (HD) serving as a putative dimerization domain, we wondered whether PrP dimerization is involved in the formation of neurotoxic and/or infectious PrP conformers. Here, we analyzed the possible impact on dimerization of pathogenic mutations in the HD that induce a spontaneous neurodegenerative disease in transgenic mice. Similarly to wildtype (WT) PrPC, the neurotoxic variant PrP(AV3) formed homodimers as well as heterodimers with WTPrPC Notably, forced PrP dimerization via an intermolecular disulfide bond did not interfere with its maturation and intracellular trafficking. Covalently linked PrP dimers were complex glycosylated, GPI-anchored, and sorted to the outer leaflet of the plasma membrane. However, forced PrPC dimerization completely blocked its conversion into PrPSc in chronically scrapie-infected mouse neuroblastoma cells. Moreover, PrPC dimers had a dominant-negative inhibition effect on the conversion of monomeric PrPC Our findings suggest that PrPC monomers are the major substrates for PrPSc propagation and that it may be possible to halt prion formation by stabilizing PrPC dimers.
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Affiliation(s)
- Anna D Engelke
- Department of Biochemistry of Neurodegenerative Diseases, Ruhr University Bochum, D-44801 Bochum, Germany
| | - Anika Gonsberg
- Department of Biochemistry of Neurodegenerative Diseases, Ruhr University Bochum, D-44801 Bochum, Germany
| | - Simrika Thapa
- Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, and Calgary Prion Research Unit, University of Calgary, Calgary, Alberta T2N 4Z6, Canada
| | - Sebastian Jung
- Department of Biochemistry of Neurodegenerative Diseases, Ruhr University Bochum, D-44801 Bochum, Germany
| | - Sarah Ulbrich
- Department of Biochemistry of Neurodegenerative Diseases, Ruhr University Bochum, D-44801 Bochum, Germany
| | - Ralf Seidel
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, D-44227 Dortmund, Germany
| | - Shaon Basu
- Department of Pharmacology and Therapeutics, McGill University, Montreal H3G 1Y6, Canada
| | - Gerd Multhaup
- Department of Pharmacology and Therapeutics, McGill University, Montreal H3G 1Y6, Canada
| | - Michael Baier
- Research Group Proteinopathies/Neurodegenerative Diseases, Centre for Biological Threats and Special Pathogens (ZBS6), Robert Koch-Institut, D-13353 Berlin, Germany
| | - Martin Engelhard
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, D-44227 Dortmund, Germany
| | - Hermann M Schätzl
- Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, and Calgary Prion Research Unit, University of Calgary, Calgary, Alberta T2N 4Z6, Canada
| | - Konstanze F Winklhofer
- Department of Molecular Cell Biology, Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum, D-44801 Bochum, Germany
| | - Jörg Tatzelt
- Department of Biochemistry of Neurodegenerative Diseases, Ruhr University Bochum, D-44801 Bochum, Germany.
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7
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Abstract
Prion diseases are characterized by the deposition of amyloids, misfolded conformers of the prion protein. The misfolded conformation is self-replicating, by a mechanism solely enciphered in the conformation of the protein. Because of low solubility and heterogeneous aggregate sizes, the detailed atomic structure of the infectious isoform is still unknown. Progress has, however, been made, and has allowed insights into the structural and disease-related mechanisms of prions. Many structural models have been proposed, and a number of them support a consensus trimeric β-helical model, significantly more complex than simple amyloid models. There is evidence that such complexity may be a necessary property of prion structure. Knowledge of the structure of prions will provide a greater understanding of the protein isoform conversion mechanism, and could eventually lead to rationally designed intervention strategies.
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Affiliation(s)
- Gerald Stubbs
- Department of Biological Sciences and Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 53723
| | - Jan Stöhr
- Institute for Neurodegenerative Diseases, Department of Neurology, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California 94143
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8
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Linden R. The Biological Function of the Prion Protein: A Cell Surface Scaffold of Signaling Modules. Front Mol Neurosci 2017; 10:77. [PMID: 28373833 PMCID: PMC5357658 DOI: 10.3389/fnmol.2017.00077] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Accepted: 03/06/2017] [Indexed: 12/18/2022] Open
Abstract
The prion glycoprotein (PrPC) is mostly located at the cell surface, tethered to the plasma membrane through a glycosyl-phosphatydil inositol (GPI) anchor. Misfolding of PrPC is associated with the transmissible spongiform encephalopathies (TSEs), whereas its normal conformer serves as a receptor for oligomers of the β-amyloid peptide, which play a major role in the pathogenesis of Alzheimer’s Disease (AD). PrPC is highly expressed in both the nervous and immune systems, as well as in other organs, but its functions are controversial. Extensive experimental work disclosed multiple physiological roles of PrPC at the molecular, cellular and systemic levels, affecting the homeostasis of copper, neuroprotection, stem cell renewal and memory mechanisms, among others. Often each such process has been heralded as the bona fide function of PrPC, despite restricted attention paid to a selected phenotypic trait, associated with either modulation of gene expression or to the engagement of PrPC with a single ligand. In contrast, the GPI-anchored prion protein was shown to bind several extracellular and transmembrane ligands, which are required to endow that protein with the ability to play various roles in transmembrane signal transduction. In addition, differing sets of those ligands are available in cell type- and context-dependent scenarios. To account for such properties, we proposed that PrPC serves as a dynamic platform for the assembly of signaling modules at the cell surface, with widespread consequences for both physiology and behavior. The current review advances the hypothesis that the biological function of the prion protein is that of a cell surface scaffold protein, based on the striking similarities of its functional properties with those of scaffold proteins involved in the organization of intracellular signal transduction pathways. Those properties are: the ability to recruit spatially restricted sets of binding molecules involved in specific signaling; mediation of the crosstalk of signaling pathways; reciprocal allosteric regulation with binding partners; compartmentalized responses; dependence of signaling properties upon posttranslational modification; and stoichiometric requirements and/or oligomerization-dependent impact on signaling. The scaffold concept may contribute to novel approaches to the development of effective treatments to hitherto incurable neurodegenerative diseases, through informed modulation of prion protein-ligand interactions.
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Affiliation(s)
- Rafael Linden
- Laboratory of Neurogenesis, Institute of Biophysics, Federal University of Rio de Janeiro Rio de Janeiro, Brazil
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9
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Chamachi NG, Chakrabarty S. Replica Exchange Molecular Dynamics Study of Dimerization in Prion Protein: Multiple Modes of Interaction and Stabilization. J Phys Chem B 2016; 120:7332-45. [DOI: 10.1021/acs.jpcb.6b03690] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Neharika G. Chamachi
- Physical and Materials Chemistry
Division, CSIR-National Chemical Laboratory, Pune 411008, India
| | - Suman Chakrabarty
- Physical and Materials Chemistry
Division, CSIR-National Chemical Laboratory, Pune 411008, India
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10
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Roucou X. Regulation of PrP(C) signaling and processing by dimerization. Front Cell Dev Biol 2014; 2:57. [PMID: 25364762 PMCID: PMC4207009 DOI: 10.3389/fcell.2014.00057] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Accepted: 09/19/2014] [Indexed: 12/15/2022] Open
Abstract
The cellular prion protein (PrPC) is a glycosylphosphatidylinositol (GPI)-anchored protein present at the cell surface. PrPC N-terminal moiety is intrinsically disordered and is able to interact with a variety of ligands. Physiological ligands have neurotrophic activity, whilst others, including protein toxic oligomers, have neurotoxic functions. These two opposite activities involve different interacting partners and result from different PrPC-activated signaling pathways. Remarkably, PrPC may be inactivated either by physiological endoproteolysis and release of the N-terminal domain, or by ectodomain shedding. Ligand-induced PrPC dimerization or enforced dimerization of PrPC indicate that PrPC dimerization represents an important molecular switch for both intracellular signaling and inactivation by the release of PrPC N-terminal domain or shedding. In this review, we summarize evidence that cell surface receptor activity of PrPC is finely regulated by dimerization.
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Affiliation(s)
- Xavier Roucou
- Department of Biochemistry, Faculty of Medicine, Université de Sherbrooke Sherbrooke, QC, Canada
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11
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Béland M, Roucou X. Homodimerization as a molecular switch between low and high efficiency PrP C cell surface delivery and neuroprotective activity. Prion 2013; 7:170-4. [PMID: 23357826 DOI: 10.4161/pri.23583] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
PrP (C) is associated with a variety of functions, and its ability to interact with a multitude of partners, including itself, may largely explain PrP multifunctionality and the lack of consensus on the genuine physiological function of the protein in vivo. In contrast, there is a consensus in the literature that alterations in PrP (C) trafficking and intracellular retention result in neuronal degeneration. In addition, a proteolytic modification in the late secretory pathway termed the α-cleavage induces the secretion of PrPN1, a PrP (C) -derived metabolite with fascinating neuroprotective activity against toxic oligomeric Aβ molecules implicated in Alzheimer disease. Thus, studies focusing on understanding the regulation of PrP (C) trafficking to the cell surface and the modulation of α-cleavage are essential. The objective of this commentary is to highlight recent evidences that PrP (C) homodimerization stimulates trafficking of the protein to the cell surface and results in high levels of PrPN1 secretion. We also discuss a hypothetical model for these results and comment on future challenges and opportunities.
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Affiliation(s)
- Maxime Béland
- Department of Biochemistry, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, QC Canada
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12
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Issack BB, Berjanskii M, Wishart DS, Stepanova M. Exploring the essential collective dynamics of interacting proteins: application to prion protein dimers. Proteins 2012; 80:1847-65. [PMID: 22488640 DOI: 10.1002/prot.24082] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2011] [Revised: 03/07/2012] [Accepted: 03/18/2012] [Indexed: 11/11/2022]
Abstract
Essential collective dynamics is a promising and robust approach for analysing the slow motions of macromolecules from short molecular dynamics trajectories. In this study, an extension of the method to treat a collection of interacting protein molecules is presented. The extension is applied to investigate the effects of dimerization on the collective dynamics of ovine prion protein molecules in two different arrangements. Examination of the structural plasticity shows that aggregation has a restricting effect on the local mobility of the prion protein molecules in the interfacial regions. Domain motions of the two dimeric ovine prion protein conformations are distinctly different and can be related to interatomic correlations at the interface. Correlated motions are among the slow collective modes extensively analysed by considering both main-chain and side-chain atoms. Correlation maps reveal the existence of a vast network of dynamically correlated side groups, which extends beyond individual subunits via interfacial interconnections. The network is formed by a core of hydrophobic side chains surrounded by hydrophilic groups at the periphery. The relevance of these findings are discussed in the context of mutations associated with prion diseases. The binding free energy of the dimeric conformations is evaluated to probe their thermodynamic stability. The descriptions afforded by the analysis of the essential collective dynamics of the prion dimers are consistent with their binding free energies. The agreement validates the extension of the methodology and provides a means of interpreting the collective dynamics in terms of the thermodynamic stability of ovine prion proteins.
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Affiliation(s)
- Bilkiss B Issack
- National Institute for Nanotechnology, National research Council, Edmonton, AB, Canada
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13
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Stojanov K, Georgieva JV, Brinkhuis RP, van Hest JC, Rutjes FP, Dierckx RAJO, de Vries EFJ, Zuhorn IS. In Vivo Biodistribution of Prion- and GM1-Targeted Polymersomes following Intravenous Administration in Mice. Mol Pharm 2012; 9:1620-7. [DOI: 10.1021/mp200621v] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Katica Stojanov
- Department
of Cell Biology,
section Membrane Cell Biology, University Medical Center Groningen,
University of Groningen, A. Deusinglaan 1, 9713 AV Groningen, The
Netherlands
| | - Julia V. Georgieva
- Department
of Cell Biology,
section Membrane Cell Biology, University Medical Center Groningen,
University of Groningen, A. Deusinglaan 1, 9713 AV Groningen, The
Netherlands
| | - René P. Brinkhuis
- Institute for
Molecules and Materials,
Radboud University Nijmegen, Heijendaalseweg 135, 6525 AJ, Nijmegen,
The Netherlands
| | - Jan C. van Hest
- Institute for
Molecules and Materials,
Radboud University Nijmegen, Heijendaalseweg 135, 6525 AJ, Nijmegen,
The Netherlands
| | - Floris P. Rutjes
- Institute for
Molecules and Materials,
Radboud University Nijmegen, Heijendaalseweg 135, 6525 AJ, Nijmegen,
The Netherlands
| | - Rudi A. J. O. Dierckx
- Department
of Nuclear Medicine
and Molecular Imaging, University Medical Center Groningen, University
of Groningen, Hanzeplein 1, 9713 GZ Groningen, The Netherlands
| | - Erik F. J. de Vries
- Department
of Nuclear Medicine
and Molecular Imaging, University Medical Center Groningen, University
of Groningen, Hanzeplein 1, 9713 GZ Groningen, The Netherlands
| | - Inge S. Zuhorn
- Department
of Cell Biology,
section Membrane Cell Biology, University Medical Center Groningen,
University of Groningen, A. Deusinglaan 1, 9713 AV Groningen, The
Netherlands
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14
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Gunther EC, Strittmatter SM. Beta-amyloid oligomers and cellular prion protein in Alzheimer's disease. J Mol Med (Berl) 2009; 88:331-8. [PMID: 19960174 DOI: 10.1007/s00109-009-0568-7] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2009] [Revised: 11/13/2009] [Accepted: 11/16/2009] [Indexed: 12/21/2022]
Abstract
Prefibrillar oligomers of the beta-amyloid peptide (A beta) are recognized as potential mediators of Alzheimer's disease (AD) pathophysiology. Deficits in synaptic function, neurotoxicity, and the progression of AD have all been linked to the oligomeric A beta assemblies rather than to A beta monomers or to amyloid plaques. However, the molecular sites of A beta oligomer action have remained largely unknown. Recently, the cellular prion protein (PrP(C)) has been shown to act as a functional receptor for A beta oligomers in brain slices. Because PrP(C) serves as the substrate for Creutzfeldt-Jakob Disease (CJD), these data suggest mechanistic similarities between the two neurodegenerative diseases. Here, we review the importance of A beta oligomers in AD, commonalities between AD and CJD, and the newly emergent role of PrP(C) as a receptor for A beta oligomers.
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Affiliation(s)
- Erik C Gunther
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, 295 Congress Ave., BCMM 436, New Haven, CT 06536-0812, USA
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15
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Structural insights into alternate aggregated prion protein forms. J Mol Biol 2009; 393:1033-42. [PMID: 19720066 DOI: 10.1016/j.jmb.2009.08.056] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2009] [Revised: 08/11/2009] [Accepted: 08/22/2009] [Indexed: 11/21/2022]
Abstract
The conversion of the cellular form of the prion protein (PrP(C)) to an abnormal, alternatively folded isoform (PrP(Sc)) is the central event in prion diseases or transmissible spongiform encephalopathies. Recent studies have demonstrated de novo generation of murine prions from recombinant prion protein (recPrP) after inoculation into transgenic and wild-type mice. These so-called synthetic prions lead to novel prion diseases with unique neuropathological and biochemical features. Moreover, the use of recPrP in an amyloid seeding assay can specifically detect and amplify various strains of prions. We employed this assay in our experiments and analyzed in detail the morphology of aggregate structures produced under defined chemical constraints. Our results suggest that changes in the concentration of guanidine hydrochloride can lead to different kinetic traces in a typical thioflavin T(ThT) assay. Morphological and structural analysis of these aggregates by atomic force microscopy indicates a variation in the structure of the PrP molecular assemblies. In particular, ThT positive PrP aggregates produced from rec mouse PrP residues 89 to 230 lead to mostly oligomeric structures at low concentrations of guanidine hydrochloride, while more amyloidal structures were observed at higher concentrations of the denaturant. These findings highlight the presence of numerous and complex pathways in deciphering prion constraints for infectivity and toxicity.
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16
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Young DS, Meersman F, Oxley D, Webster J, Gill AC, Bronstein I, Lowe CR, Dear DV. Effect of enzymatic deimination on the conformation of recombinant prion protein. BIOCHIMICA ET BIOPHYSICA ACTA 2009; 1794:1123-33. [PMID: 19341825 DOI: 10.1016/j.bbapap.2009.03.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2008] [Revised: 03/19/2009] [Accepted: 03/20/2009] [Indexed: 12/01/2022]
Abstract
Deimination is the post-translational conversion of arginine residues to citrulline. It has been implicated as a causative factor in autoimmune diseases such as multiple sclerosis and rheumatoid arthritis and more recently, as a marker of neurodegeneration. We have investigated the effect of the post-translational modification of arginine residues on the structure of recombinant ovine prion protein. Deiminated prion protein exhibited biophysical properties characteristic of the scrapie-associated conformer of prion protein viz. an increased beta-sheet secondary structure, congophilic structures indicative of amyloid and proteinase K resistance which could be templated onto normal unmodified prion protein. In the light of these findings, a potential role of post-translational modifications to prion protein in disease initiation or propagation is discussed.
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Affiliation(s)
- Duncan S Young
- Institute of Biotechnology, University of Cambridge, Tennis Court Road, Cambridge, UK
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17
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Stress-protective signalling of prion protein is corrupted by scrapie prions. EMBO J 2008; 27:1974-84. [PMID: 18566584 DOI: 10.1038/emboj.2008.122] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2008] [Accepted: 05/30/2008] [Indexed: 01/11/2023] Open
Abstract
Studies in transgenic mice revealed that neurodegeneration induced by scrapie prion (PrP(Sc)) propagation is dependent on neuronal expression of the cellular prion protein PrP(C). On the other hand, there is evidence that PrP(C) itself has a stress-protective activity. Here, we show that the toxic activity of PrP(Sc) and the protective activity of PrP(C) are interconnected. With a novel co-cultivation assay, we demonstrate that PrP(Sc) can induce apoptotic signalling in PrP(C)-expressing cells. However, cells expressing PrP mutants with an impaired stress-protective activity were resistant to PrP(Sc)-induced toxicity. We also show that the internal hydrophobic domain promotes dimer formation of PrP and that dimerization of PrP is linked to its stress-protective activity. PrP mutants defective in dimer formation did not confer enhanced stress tolerance. Moreover, in chronically scrapie-infected neuroblastoma cells the amount of PrP(C) dimers inversely correlated with the amount of PrP(Sc) and the resistance of the cells to various stress conditions. Our results provide new insight into the mechanism of PrP(C)-mediated neuroprotection and indicate that pathological PrP conformers abuse PrP(C)-dependent pathways for apoptotic signalling.
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18
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Kaimann T, Metzger S, Kuhlmann K, Brandt B, Birkmann E, Höltje HD, Riesner D. Molecular Model of an α-Helical Prion Protein Dimer and Its Monomeric Subunits as Derived from Chemical Cross-linking and Molecular Modeling Calculations. J Mol Biol 2008; 376:582-96. [DOI: 10.1016/j.jmb.2007.11.035] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2007] [Revised: 10/19/2007] [Accepted: 11/13/2007] [Indexed: 11/28/2022]
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19
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Biswas S, Langeveld JPM, Tipper D, Lu S. Intracellular accumulation of a 46 kDa species of mouse prion protein as a result of loss of glycosylation in cultured mammalian cells. Biochem Biophys Res Commun 2006; 349:153-61. [PMID: 16935263 DOI: 10.1016/j.bbrc.2006.08.035] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2006] [Accepted: 08/04/2006] [Indexed: 11/18/2022]
Abstract
Prion diseases are fatal neurodegenerative disorders characterized by the accumulation of an abnormal isoform (PrPSc) of the normal cellular prion protein (PrPC) in the brain. Reportedly, abnormal N-linked glycosylation patterns in PrPC are associated with disease susceptibility; thus, we compared the glycosylation status of normal and several mutant forms of the murine prion protein (MuPrP) in cultured mammalian cells. Substitution of the N-terminal signal sequence of normal MuPrP with a heterologous signal peptide did not alter glycosylation. When expressed without the C-terminal glycophosphatidylinositol anchor signal, the majority of MuPrP remained intracellular and unglycosylated, and a 46 kDa species (p46) of the unglycosylated PrPC was detected on reducing gels. p46 was also observed when wild-type MuPrP was expressed in the presence of tunicamycin or enzymatically deglycosylated in vitro. A rabbit polyclonal anti-serum raised against dimeric MuPrP cross-reacted with p46 and localized the signal within the Golgi apparatus. We propose that the 46 kDa signal is a dimeric form of MuPrP and in the light of recent studies, it can be argued that a relatively stable, non-glycosylated, cytoplasmic PrPC dimer, produced as a result of compromised glycosylation is an intermediate in initiating conversion of PrPC to PrPSc in sporadic transmissible spongiform encephalopathies.
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Affiliation(s)
- Subhabrata Biswas
- Laboratory of Nucleic Acid Vaccines, Department of Medicine, University of Massachusetts Medical School, 364 Plantation St., Worcester, MA 01605, USA
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20
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Inouye H, Kirschner DA. X-Ray fiber and powder diffraction of PrP prion peptides. ADVANCES IN PROTEIN CHEMISTRY 2006; 73:181-215. [PMID: 17190614 DOI: 10.1016/s0065-3233(06)73006-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A conformational change from the alpha-helical, cellular form of prion to the beta-sheet, scrapie (infectious) form is the central event for prion replication. The folding mechanism underlying this conformational change has not yet been deciphered. Here, we review prion pathology and summarize X-ray fiber and powder diffraction studies on the N-terminal fragments of prion protein and on short sequences that initiate the beta-assembly for various fibrils, including poly(L-alanine) and poly(L-glutamine). We discuss how the quarter-staggered beta-sheet assembly (like in polyalanine) and polar-zipper beta-sheet formation (like in polyglutamine) may be involved in the formation of the scrapie form of prion.
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Affiliation(s)
- Hideyo Inouye
- Department of Biology, Boston College, Chestnut Hill, Massachusetts 02467, USA
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21
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Barron RM, Baybutt H, Tuzi NL, McCormack J, King D, Moore RC, Melton DW, Manson JC. Polymorphisms at codons 108 and 189 in murine PrP play distinct roles in the control of scrapie incubation time. J Gen Virol 2005; 86:859-868. [PMID: 15722549 DOI: 10.1099/vir.0.80525-0] [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: 12/30/2022] Open
Abstract
Susceptibility to transmissible spongiform encephalopathies (TSEs) is associated strongly with PrP polymorphisms in humans, sheep and rodents. In mice, scrapie incubation time is controlled by polymorphisms at PrP codons 108 (leucine or phenylalanine) and 189 (threonine or valine), but the precise role of each polymorphism in the control of disease is unknown. The L108F and T189V polymorphisms are present in distinct structural regions of PrP and thus provide an excellent model with which to investigate the role of PrP structure and gene variation in TSEs. Two unique lines of transgenic mice, in which 108F and 189V have been targeted separately into the endogenous murine Prnp
a gene, have been produced. TSE inoculation of inbred lines of mice expressing all allelic combinations at codons 108 and 189 has revealed a complex relationship between PrP allele and incubation time. It has been established that both codons 108 and 189 control TSE incubation time, and that each polymorphism plays a distinct role in the disease process. Comparison of ME7 incubation times in mouse lines that are heterozygous at both codons has also identified a previously unrecognized intramolecular interaction between PrP codons 108 and 189.
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Affiliation(s)
- Rona M Barron
- Neuropathogenesis Unit, Institute for Animal Health, Ogston Building, West Mains Road, Edinburgh EH9 3JF, UK
| | - Herbert Baybutt
- Neuropathogenesis Unit, Institute for Animal Health, Ogston Building, West Mains Road, Edinburgh EH9 3JF, UK
| | - Nadia L Tuzi
- Neuropathogenesis Unit, Institute for Animal Health, Ogston Building, West Mains Road, Edinburgh EH9 3JF, UK
| | - James McCormack
- Neuropathogenesis Unit, Institute for Animal Health, Ogston Building, West Mains Road, Edinburgh EH9 3JF, UK
| | - Declan King
- Neuropathogenesis Unit, Institute for Animal Health, Ogston Building, West Mains Road, Edinburgh EH9 3JF, UK
| | - Richard C Moore
- Institute of Cell and Molecular Biology, University of Edinburgh, Edinburgh, UK
| | - David W Melton
- Sir Alastair Currie Cancer Research UK Laboratories, Molecular Medicine Centre, University of Edinburgh, Western General Hospital, Edinburgh, UK
| | - Jean C Manson
- Neuropathogenesis Unit, Institute for Animal Health, Ogston Building, West Mains Road, Edinburgh EH9 3JF, UK
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22
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Leffers KW, Schell J, Jansen K, Lucassen R, Kaimann T, Nagel-Steger L, Tatzelt J, Riesner D. The structural transition of the prion protein into its pathogenic conformation is induced by unmasking hydrophobic sites. J Mol Biol 2005; 344:839-53. [PMID: 15533449 DOI: 10.1016/j.jmb.2004.09.071] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2004] [Accepted: 09/24/2004] [Indexed: 11/18/2022]
Abstract
A series of structural intermediates in the putative pathway from the cellular prion protein PrP(C) to the pathogenic form PrP(Sc) was established by systematic variation of low concentrations (<0.1%) of the detergent sodium dodecyl sulfate (SDS) or by the interaction with the bacterial chaperonin GroEL. Most extended studies were carried out with recombinant PrP (90-231) corresponding to the amino acid sequence of hamster prions PrP 27-30. Similar results were obtained with full-length recombinant PrP, hamster PrP 27-30 and PrP(C) isolated from transgenic, non-infected CHO cells. Varying the incubation conditions, i.e. the concentration of SDS, the GroEL and GroEL/ES, but always at neutral pH and room temperature, different conformations could be established. The conformations were characterized with respect to secondary structure as determined by CD spectroscopy and to molecular mass, as determined by fluorescence correlation spectroscopy and analytical ultracentrifugation: alpha-helical monomers, soluble alpha-helical dimers, soluble but beta-structured oligomers of a minimal size of 12-14 PrP molecules, and insoluble multimers were observed. A high activation barrier was found between the alpha-helical dimers and beta-structured oligomers. The numbers of SDS-molecules bound to PrP in different conformations were determined: Partially denatured, alpha-helical monomers bind 31 SDS molecules per PrP molecule, alpha-helical dimers 21, beta-structured oligomers 19-20, and beta-structured multimers show very strong binding of five SDS molecules per PrP molecule. Binding of only five molecules of SDS per molecule of PrP leads to fast formation of beta-structures followed by irreversible aggregation. It is discussed that strongest binding of SDS has an effect identical with or similar to the interaction with GroEL thereby inducing identical or very similar transitions. The interaction with GroEL/ES stabilizes the soluble, alpha-helical conformation. The structure and their stabilities and particularly the induction of transitions by interaction of hydrophobic sites of PrP are discussed in respect to their biological relevance.
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Affiliation(s)
- K-W Leffers
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany
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23
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Hundt C, Weiss S. The prion-like protein Doppel fails to interact with itself, the prion protein and the 37 kDa/67 kDa laminin receptor in the yeast two-hybrid system. Biochim Biophys Acta Mol Basis Dis 2004; 1689:1-5. [PMID: 15158907 DOI: 10.1016/j.bbadis.2004.02.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2003] [Revised: 02/13/2004] [Accepted: 02/17/2004] [Indexed: 11/21/2022]
Abstract
The prion-like protein termed Doppel (Dpl) shows approx. 25% sequence identity with all known prion proteins (PrP). We recently showed that the cellular PrP is dimeric under native conditions, a finding which was confirmed by the investigation of its crystal structure. Human PrP further interacts with its cellular receptor, the 37 kDa/67 kDa laminin receptor (LRP/LR). Here we report that human Doppel fails to interact with (i). itself, (ii). the human 37 kDa/67 kDa LRP/LR, and (iii). the human cellular prion protein (huPrP) in the yeast two-hybrid system. Our findings suggest that Dpl and PrP are not related or are only marginally related with respect to their ligand binding behaviour.
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Affiliation(s)
- Christoph Hundt
- Laboratorium für Molekulare Biologie-Genzentrum-Institut für Biochemie der Ludwig-Maximilians-Universität München, Feodor-Lynen-Str. 25, D-81377 Munich, Germany
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24
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Soldevila M, Andrés AM, Blancher A, Calafell F, Ordoñez M, Pumarola M, Oliva B, Aramburu J, Bertranpetit J. Variation of the prion gene in chimpanzees and its implication for prion diseases. Neurosci Lett 2004; 355:157-60. [PMID: 14732455 DOI: 10.1016/j.neulet.2003.09.073] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In humans, familial prion diseases are linked to mutations in the PRNP gene. We have sequenced part of this gene in a large sample of common chimpanzee, Pan troglodytes (n=130 chromosomes). No variation in codons 129 and 219 has been observed: all chimpanzees were homozygous for the Met allele, which in humans increases susceptibility to Creutzfeldt-Jakob disease. We found two sequence variants: one is a synonymous polymorphism unique to the chimpanzee at codon 226, TAC to TAT (Y), with a TAC allele frequency of 80.6%; the other is a non-synonymous change at codon 148 (R148H) that falls in the target epitope for some common commercial antibodies used for prion diagnostics, and is highly conserved across species. The pathogenicity of this mutation is still unknown.
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Affiliation(s)
- M Soldevila
- Unitat de Biologia Evolutiva, Facultat de Ciències de la Salut i de la Vida, Universitat Pompeu Fabra, Dr Aiguader 80, 08003 Barcelona, Spain
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25
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Grossman A, Zeiler B, Sapirstein V. Prion protein interactions with nucleic acid: possible models for prion disease and prion function. Neurochem Res 2003; 28:955-63. [PMID: 12718450 DOI: 10.1023/a:1023215207981] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Several models for the transmission and progression of prion diseases have arisen, evolving with the acquisition of new experimental results. It is generally accepted that the PrP(Sc) protein is at least part of the infectious particle and the major protein component of the scrapie-associated fibrils (SAFs) that characterize the disease. An additional, unknown cofactor is most likely involved in transmission of the disease, perhaps by influencing the PrP(c) --> PrP(Sc) transition. This review relates experimental observations on the interactions of nucleic acids (NAs) and PrP with specific focus on alterations in structure. In particular, NAs appear to induce PrP(c) to acquire some of the structural and biochemical characteristics of PrP(Sc). An updated hypothesis is related wherein NAs, on the basis of their structure, act in the PrP(c) --> PrP(Sc) transformation by serving as catalysts and/or chaperones and not by encoding genetic information.
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Affiliation(s)
- Abraham Grossman
- Q-RNA, Inc., 3960 Broadway, Suite 407, New York, New York 10032, USA.
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26
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Abstract
The central theme in prion diseases is the conformational transition of a cellular protein from a physiologic to a pathologic (so-called scrapie) state. Currently, two alternative models exist for the mechanism of this autocatalytic process; in the template assistance model the prion is assumed to be a monomer of the scrapie conformer, whereas in the nucleated polymerization model it is thought to be an amyloid rod. A recent variation on the latter assumes disulfide reshuffling as the mechanism of polymerization. The existence of stable dimers, let alone their mechanistic role, is not taken into account in either of these models. In this paper we review evidence supporting that the dimerization of either the normal or the scrapie state, or both, has a decisive role in prion replication. The contribution of redox changes, i.e., the temporary opening and possible rearrangement of the intramolecular disulfide bridge is also considered. We present a model including these features largely ignored so far and show that it adheres satisfactorily to the observed phenomenology of prion replication.
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Affiliation(s)
- Peter Tompa
- Institute of Enzymology, Biological Research Center, Hungarian Academy of Sciences, Budapest
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