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Celauro L, Zattoni M, Legname G. Prion receptors, prion internalization, intra- and inter-cellular transport. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2023; 196:15-41. [PMID: 36813357 DOI: 10.1016/bs.pmbts.2022.06.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- Luigi Celauro
- Laboratory of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy
| | - Marco Zattoni
- Laboratory of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy
| | - Giuseppe Legname
- Laboratory of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy.
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2
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Prion Protein Biology Through the Lens of Liquid-Liquid Phase Separation. J Mol Biol 2021; 434:167368. [PMID: 34808226 DOI: 10.1016/j.jmb.2021.167368] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 11/12/2021] [Accepted: 11/14/2021] [Indexed: 12/29/2022]
Abstract
Conformational conversion of the α-helix-rich cellular prion protein into the misfolded, β-rich, aggregated, scrapie form underlies the molecular basis of prion diseases that represent a class of invariably fatal, untreatable, and transmissible neurodegenerative diseases. However, despite the extensive and rigorous research, there is a significant gap in the understanding of molecular mechanisms that contribute to prion pathogenesis. In this review, we describe the historical perspective of the development of the prion concept and the current state of knowledge of prion biology including structural, molecular, and cellular aspects of the prion protein. We then summarize the putative functional role of the N-terminal intrinsically disordered segment of the prion protein. We next describe the ongoing efforts in elucidating the prion phase behavior and the emerging role of liquid-liquid phase separation that can have potential functional relevance and can offer an alternate non-canonical pathway involving conformational conversion into a disease-associated form. We also attempt to shed light on the evolutionary perspective of the prion protein highlighting the potential role of intrinsic disorder in prion protein biology and summarize a few important questions associated with the phase transitions of the prion protein. Delving deeper into these key aspects can pave the way for a detailed understanding of the critical molecular determinants of the prion phase transition and its relevance to physiology and neurodegenerative diseases.
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3
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The Cellular Prion Protein: A Promising Therapeutic Target for Cancer. Int J Mol Sci 2020; 21:ijms21239208. [PMID: 33276687 PMCID: PMC7730109 DOI: 10.3390/ijms21239208] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 11/28/2020] [Accepted: 11/30/2020] [Indexed: 12/20/2022] Open
Abstract
Studies on the cellular prion protein (PrPC) have been actively conducted because misfolded PrPC is known to cause transmissible spongiform encephalopathies or prion disease. PrPC is a glycophosphatidylinositol-anchored cell surface glycoprotein that has been reported to affect several cellular functions such as stress protection, cellular differentiation, mitochondrial homeostasis, circadian rhythm, myelin homeostasis, and immune modulation. Recently, it has also been reported that PrPC mediates tumor progression by enhancing the proliferation, metastasis, and drug resistance of cancer cells. In addition, PrPC regulates cancer stem cell properties by interacting with cancer stem cell marker proteins. In this review, we summarize how PrPC promotes tumor progression in terms of proliferation, metastasis, drug resistance, and cancer stem cell properties. In addition, we discuss strategies to treat tumors by modulating the function and expression of PrPC via the regulation of HSPA1L/HIF-1α expression and using an anti-prion antibody.
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A New Take on Prion Protein Dynamics in Cellular Trafficking. Int J Mol Sci 2020; 21:ijms21207763. [PMID: 33092231 PMCID: PMC7589859 DOI: 10.3390/ijms21207763] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 10/14/2020] [Accepted: 10/14/2020] [Indexed: 12/12/2022] Open
Abstract
The mobility of cellular prion protein (PrPC) in specific cell membrane domains and among distinct cell compartments dictates its molecular interactions and directs its cell function. PrPC works in concert with several partners to organize signaling platforms implicated in various cellular processes. The scaffold property of PrPC is able to gather a molecular repertoire to create heterogeneous membrane domains that favor endocytic events. Dynamic trafficking of PrPC through multiple pathways, in a well-orchestrated mechanism of intra and extracellular vesicular transport, defines its functional plasticity, and also assists the conversion and spreading of its infectious isoform associated with neurodegenerative diseases. In this review, we highlight how PrPC traffics across intra- and extracellular compartments and the consequences of this dynamic transport in governing cell functions and contributing to prion disease pathogenesis.
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Abstract
During the course of prion infection, the normally soluble and protease-sensitive mammalian prion protein (PrPC) is refolded into an insoluble, partially protease-resistant, and infectious form called PrPSc. The conformational conversion of PrPC to PrPSc is a critical event during prion infection and is essential for the production of prion infectivity. This chapter briefly summarizes the ways in which cell biological approaches have enhanced our understanding of how PrP contributes to different aspects of prion pathogenesis.
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Lysosomal response in relation to α-synuclein pathology differs between Parkinson's disease and multiple system atrophy. Neurobiol Dis 2018; 114:140-152. [PMID: 29505813 DOI: 10.1016/j.nbd.2018.02.019] [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: 10/23/2017] [Revised: 01/26/2018] [Accepted: 02/27/2018] [Indexed: 12/20/2022] Open
Abstract
Intracellular deposition of pathologically altered α-synuclein mostly in neurons characterises Parkinson's disease (PD), while its accumulation predominantly in oligodendrocytes is a feature of multiple system atrophy (MSA). Recently a prion-like spreading of pathologic α-synuclein has been suggested to play a role in the pathogenesis of PD and MSA. This implicates a role of protein processing systems, including lysosomes, supported also by genetic studies in PD. However, particularly for MSA, the mechanism of cell-to-cell propagation of α-synuclein is yet not fully understood. To evaluate the significance of lysosomal response, we systematically compared differently affected neuronal populations in PD, MSA, and non-diseased brains using morphometric immunohistochemistry (cathepsin D), double immunolabelling (cathepsin D/α-synuclein) laser confocal microscopy, and immunogold electron microscopy for the disease associated α-synuclein. We found that i) irrespective of the presence of neuronal inclusions, the volume density of cathepsin D immunoreactivity significantly increases in affected neurons of the pontine base in MSA brains; ii) volume density of cathepsin D immunoreactivity increases in nigral neurons in PD without inclusions and with non-ubiquitinated pre-aggregates of α-synuclein, but not in neurons with Lewy bodies; iii) cathepsin D immunoreactivity frequently colocalises with α-synuclein pre-aggregates in nigral neurons in PD; iv) ultrastructural observations confirm disease-associated α-synuclein in neuronal and astrocytic lysosomes in PD; v) lysosome-associated α-synuclein is observed in astroglia and rarely in oligodendroglia and in neurons in MSA. Our observations support a crucial role for the neuronal endosomal-lysosomal system in the processing of α-synuclein in PD. We suggest a distinct contribution of lysosomes to the pathogenesis of MSA, including the possibility of oligodendroglial and eventually neuronal uptake of exogenous α-synuclein in MSA.
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Lathe R, Darlix JL. Prion Protein PRNP: A New Player in Innate Immunity? The Aβ Connection. J Alzheimers Dis Rep 2017; 1:263-275. [PMID: 30480243 PMCID: PMC6159716 DOI: 10.3233/adr-170037] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/11/2017] [Indexed: 12/25/2022] Open
Abstract
The prion protein PRNP has been centrally implicated in the transmissible spongiform encephalopathies (TSEs), but its normal physiological role remains obscure. We highlight emerging evidence that PRNP displays antimicrobial activity, inhibiting the replication of multiple viruses, and also interacts directly with Alzheimer's disease (AD) amyloid-β (Aβ) peptide whose own antimicrobial role is now increasingly secure. PRNP and Aβ share share membrane-penetrating, nucleic acid binding, and antiviral properties with classical antimicrobial peptides such as LL-37. We discuss findings that binding of abnormal nucleic acids to PRNP leads to oligomerization of the protein, and suggest that this may be an entrapment and sequestration process that contributes to its antimicrobial activity. Some antimicrobial peptides are known to be exploited by infectious agents, and we cover evidence that PRNP is usurped by herpes simplex virus (HSV-1) that has evolved a virus-encoded 'anti-PRNP'.unction. These findings suggest that PRNP, like LL-37 and Aβ, is likely to be a component of the innate immune system, with implications for the pathoetiology of both AD and TSE.
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Affiliation(s)
- Richard Lathe
- Division of Infection and Pathway Medicine, University of Edinburgh, Edinburgh, UK
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Pushchino, Moscow Region, Russia
| | - Jean-Luc Darlix
- Faculté de Pharmacie, Centre Nationale de la Recherche Scientifique (CNRS) Unité 7213, Université de Strasbourg, Illkirch, France
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Cheng L, Zhao W, Hill AF. Exosomes and their role in the intercellular trafficking of normal and disease associated prion proteins. Mol Aspects Med 2017; 60:62-68. [PMID: 29196098 DOI: 10.1016/j.mam.2017.11.011] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 11/08/2017] [Accepted: 11/27/2017] [Indexed: 12/13/2022]
Abstract
Over the past decade, small extracellular vesicles called exosomes have been observed to harbour protein and genetic cargo that can assist in health and also cause disease. Many groups are extensively investigating the mechanisms involved that regulate the trafficking and packaging of exosomal contents and how these processes may be deregulated in disease. Prion diseases are transmissible neurodegenerative disorders and are characterized by the presence of detectable misfolded prion proteins. The disease associated form of the prion protein can be found in exosomes and its transmissible properties have provided a reliable experimental read out that can be used to understand how exosomes and their cargo are involved in cell-cell communication and in the spread of prion diseases. This review reports on the current understanding of how exosomes are involved in the intercellular spread of infectious prions. Furthermore, we discuss how these principles are leading future investigations in developing new exosome based diagnostic tools and therapeutic drugs that could be applied to other neurodegenerative diseases.
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Affiliation(s)
- Lesley Cheng
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Australia
| | - Wenting Zhao
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Australia
| | - Andrew F Hill
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Australia.
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9
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Sarnataro D, Pepe A, Zurzolo C. Cell Biology of Prion Protein. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2017; 150:57-82. [PMID: 28838675 DOI: 10.1016/bs.pmbts.2017.06.018] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Cellular prion protein (PrPC) is a mammalian glycoprotein which is usually found anchored to the plasma membrane via a glycosylphosphatidylinositol (GPI) anchor. The precise function of PrPC remains elusive but may depend upon its cellular localization. PrPC misfolds to a pathogenic isoform PrPSc, the causative agent of neurodegenerative prion diseases. Nonetheless some forms of prion disease develop in the apparent absence of infectious PrPSc, suggesting that molecular species of PrP distinct from PrPSc may represent the primary neurotoxic culprits. Indeed, in some inherited cases of human prion disease, the predominant form of PrP detectable in the brain is not PrPSc but rather CtmPrP, a transmembrane form of the protein. The relationship between the neurodegeneration occurring in prion diseases involving PrPSc and that associated with CtmPrP remains unclear. However, the different membrane topology of the PrP mutants, as well as the presence of the GPI anchor, could influence both the function and the intracellular localization and trafficking of the protein, all being potentially very important in the pathophysiological mechanism that ultimately causes the disease. Here, we review the latest findings on the fundamental aspects of prions biology, from the PrPC biosynthesis, function, and structure up to its intracellular traffic and analyze the possible roles of the different topological isoforms of the protein, as well as the GPI anchor, in the pathogenesis of the disease.
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Affiliation(s)
- Daniela Sarnataro
- University of Naples "Federico II", Naples, Italy; Ceinge-Biotecnologie avanzate, s.c.a r.l., Naples, Italy.
| | - Anna Pepe
- University of Naples "Federico II", Naples, Italy; Unité de Trafic Membranaire et Pathogenese, Institut Pasteur, Paris, France
| | - Chiara Zurzolo
- University of Naples "Federico II", Naples, Italy; Unité de Trafic Membranaire et Pathogenese, Institut Pasteur, Paris, France
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10
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Majumder P, Chakrabarti O. Lysosomal Quality Control in Prion Diseases. Mol Neurobiol 2017; 55:2631-2644. [PMID: 28421536 DOI: 10.1007/s12035-017-0512-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 04/04/2017] [Indexed: 11/28/2022]
Abstract
Prion diseases are transmissible, familial or sporadic. The prion protein (PrP), a normal cell surface glycoprotein, is ubiquitously expressed throughout the body. While loss of function of PrP does not elicit apparent phenotypes, generation of misfolded forms of the protein or its aberrant metabolic isoforms has been implicated in a number of neurodegenerative disorders such as scrapie, kuru, Creutzfeldt-Jakob disease, fatal familial insomnia, Gerstmann-Sträussler-Scheinker and bovine spongiform encephalopathy. These diseases are all phenotypically characterised by spongiform vacuolation of the adult brain, hence collectively termed as late-onset spongiform neurodegeneration. Misfolded form of PrP (PrPSc) and one of its abnormal metabolic isoforms (the transmembrane CtmPrP) are known to be disease-causing agents that lead to progressive loss of structure or function of neurons culminating in neuronal death. The aberrant forms of PrP utilise and manipulate the various intracellular quality control mechanisms during pathogenesis of these diseases. Amongst these, the lysosomal quality control machinery emerges as one of the primary targets exploited by the disease-causing isoforms of PrP. The autophagosomal-lysosomal degradation pathway is adversely affected in multiple ways in prion diseases and may hence be regarded as an important modulator of neurodegeneration. Some of the ESCRT pathway proteins have also been shown to be involved in the manifestation of disease phenotype. This review discusses the significance of the lysosomal quality control pathway in affecting transmissible and familial types of prion diseases.
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Affiliation(s)
- Priyanka Majumder
- Biophysics and Structural Genomics Division, Saha Institute of Nuclear Physics, Sector-1, Block-AF, Bidhannagar, Kolkata, West Bengal, 700064, India
| | - Oishee Chakrabarti
- Biophysics and Structural Genomics Division, Saha Institute of Nuclear Physics, Sector-1, Block-AF, Bidhannagar, Kolkata, West Bengal, 700064, India.
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Castle AR, Gill AC. Physiological Functions of the Cellular Prion Protein. Front Mol Biosci 2017; 4:19. [PMID: 28428956 PMCID: PMC5382174 DOI: 10.3389/fmolb.2017.00019] [Citation(s) in RCA: 122] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 03/22/2017] [Indexed: 01/09/2023] Open
Abstract
The prion protein, PrPC, is a small, cell-surface glycoprotein notable primarily for its critical role in pathogenesis of the neurodegenerative disorders known as prion diseases. A hallmark of prion diseases is the conversion of PrPC into an abnormally folded isoform, which provides a template for further pathogenic conversion of PrPC, allowing disease to spread from cell to cell and, in some circumstances, to transfer to a new host. In addition to the putative neurotoxicity caused by the misfolded form(s), loss of normal PrPC function could be an integral part of the neurodegenerative processes and, consequently, significant research efforts have been directed toward determining the physiological functions of PrPC. In this review, we first summarise important aspects of the biochemistry of PrPC before moving on to address the current understanding of the various proposed functions of the protein, including details of the underlying molecular mechanisms potentially involved in these functions. Over years of study, PrPC has been associated with a wide array of different cellular processes and many interacting partners have been suggested. However, recent studies have cast doubt on the previously well-established links between PrPC and processes such as stress-protection, copper homeostasis and neuronal excitability. Instead, the functions best-supported by the current literature include regulation of myelin maintenance and of processes linked to cellular differentiation, including proliferation, adhesion, and control of cell morphology. Intriguing connections have also been made between PrPC and the modulation of circadian rhythm, glucose homeostasis, immune function and cellular iron uptake, all of which warrant further investigation.
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Ballmer BA, Moos R, Liberali P, Pelkmans L, Hornemann S, Aguzzi A. Modifiers of prion protein biogenesis and recycling identified by a highly parallel endocytosis kinetics assay. J Biol Chem 2017; 292:8356-8368. [PMID: 28341739 DOI: 10.1074/jbc.m116.773283] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 03/17/2017] [Indexed: 11/06/2022] Open
Abstract
The cellular prion protein, PrPC, is attached by a glycosylphosphatidylinositol anchor to the outer leaflet of the plasma membrane. Its misfolded isoform PrPSc is the causative agent of prion diseases. Conversion of PrPC into PrPSc is thought to take place at the cell surface or in endolysosomal organelles. Understanding the intracellular trafficking of PrPC may, therefore, help elucidate the conversion process. Here we describe a time-resolved fluorescence energy transfer (FRET) assay reporting membrane expression and real-time internalization rates of PrPC The assay is suitable for high-throughput genetic and pharmaceutical screens for modulators of PrPC trafficking. Simultaneous administration of FRET donor and acceptor anti-PrPC antibodies to living cells yielded a measure of PrPC surface density, whereas sequential addition of each antibody visualized the internalization rate of PrPC (Z' factor >0.5). RNA interference assays showed that suppression of AP2M1 (AP-2 adaptor protein), RAB5A, VPS35 (vacuolar protein sorting 35 homolog), and M6PR (mannose 6-phosphate receptor) blocked PrPC internalization, whereas down-regulation of GIT2 and VPS28 increased PrPC internalization. PrPC cell-surface expression was reduced by down-regulation of RAB5A, VPS28, and VPS35 and enhanced by silencing EHD1. These data identify a network of proteins implicated in PrPC trafficking and demonstrate the power of this assay for identifying modulators of PrPC trafficking.
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Affiliation(s)
- Boris A Ballmer
- Institute of Neuropathology, University of Zurich, CH-8091 Zurich, Switzerland
| | - Rita Moos
- Institute of Neuropathology, University of Zurich, CH-8091 Zurich, Switzerland
| | - Prisca Liberali
- Institute of Molecular Life Sciences, University of Zurich, CH-8091 Zurich, Switzerland; Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Lucas Pelkmans
- Institute of Molecular Life Sciences, University of Zurich, CH-8091 Zurich, Switzerland
| | - Simone Hornemann
- Institute of Neuropathology, University of Zurich, CH-8091 Zurich, Switzerland.
| | - Adriano Aguzzi
- Institute of Neuropathology, University of Zurich, CH-8091 Zurich, Switzerland.
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Beraldo FH, Ostapchenko VG, Caetano FA, Guimaraes ALS, Ferretti GDS, Daude N, Bertram L, Nogueira KOPC, Silva JL, Westaway D, Cashman NR, Martins VR, Prado VF, Prado MAM. Regulation of Amyloid β Oligomer Binding to Neurons and Neurotoxicity by the Prion Protein-mGluR5 Complex. J Biol Chem 2016; 291:21945-21955. [PMID: 27563063 DOI: 10.1074/jbc.m116.738286] [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: 05/20/2016] [Indexed: 12/24/2022] Open
Abstract
The prion protein (PrPC) has been suggested to operate as a scaffold/receptor protein in neurons, participating in both physiological and pathological associated events. PrPC, laminin, and metabotropic glutamate receptor 5 (mGluR5) form a protein complex on the plasma membrane that can trigger signaling pathways involved in neuronal differentiation. PrPC and mGluR5 are co-receptors also for β-amyloid oligomers (AβOs) and have been shown to modulate toxicity and neuronal death in Alzheimer's disease. In the present work, we addressed the potential crosstalk between these two signaling pathways, laminin-PrPC-mGluR5 or AβO-PrPC-mGluR5, as well as their interplay. Herein, we demonstrated that an existing complex containing PrPC-mGluR5 has an important role in AβO binding and activity in neurons. A peptide mimicking the binding site of laminin onto PrPC (Ln-γ1) binds to PrPC and induces intracellular Ca2+ increase in neurons via the complex PrPC-mGluR5. Ln-γ1 promotes internalization of PrPC and mGluR5 and transiently decreases AβO biding to neurons; however, the peptide does not impact AβO toxicity. Given that mGluR5 is critical for toxic signaling by AβOs and in prion diseases, we tested whether mGlur5 knock-out mice would be susceptible to prion infection. Our results show mild, but significant, effects on disease progression, without affecting survival of mice after infection. These results suggest that PrPC-mGluR5 form a functional response unit by which multiple ligands can trigger signaling. We propose that trafficking of PrPC-mGluR5 may modulate signaling intensity by different PrPC ligands.
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Affiliation(s)
| | | | - Fabiana A Caetano
- From the Robarts Research Institute and the Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario N6A 5B7,Canada
| | - Andre L S Guimaraes
- From the Robarts Research Institute and the Universidade Estadual de Montes Claros, Montes Claros, MG 39401-089, Brazil
| | - Giulia D S Ferretti
- From the Robarts Research Institute and the Programa de Biologia Estrutural, Instituto de Bioquimica Medica Leopoldo de Meis, Instututo Nacional de Biologia Estrutural e Bioimagem, Centro Nacional de Ressonacia Magnetica Nuclear Jiri Jonas, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-901, Brazil
| | - Nathalie Daude
- the Center for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta T6G 2M8, Canada
| | - Lisa Bertram
- the Center for Brain Health, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Katiane O P C Nogueira
- From the Robarts Research Institute and the Instituto de Ciências Exatas e Biológicas, Departamento de Ciências Biológicas, Universidade Federal de Ouro Preto, Campus Morro do Cruzeiro S/N, Ouro Preto, Minas Gerais 35400-000, Brazil
| | - Jerson L Silva
- the Programa de Biologia Estrutural, Instituto de Bioquimica Medica Leopoldo de Meis, Instututo Nacional de Biologia Estrutural e Bioimagem, Centro Nacional de Ressonacia Magnetica Nuclear Jiri Jonas, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-901, Brazil
| | - David Westaway
- the Center for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta T6G 2M8, Canada
| | - Neil R Cashman
- the Center for Brain Health, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Vilma R Martins
- the International Center for Research and Education, A. C. Camargo Cancer Center, São Paulo, SP CEP 01509-010, Brazil, and
| | - Vania F Prado
- From the Robarts Research Institute and the Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario N6A 5B7,Canada, the Department of Anatomy and Cell Biology, University of Western Ontario, London, Ontario N6A 3K7, Canada
| | - Marco A M Prado
- From the Robarts Research Institute and the Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario N6A 5B7,Canada, the Department of Anatomy and Cell Biology, University of Western Ontario, London, Ontario N6A 3K7, Canada
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14
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Mahmutefendić H, Blagojević Zagorac G, Grabušić K, Karleuša L, Maćešić S, Momburg F, Lučin P. Late Endosomal Recycling of Open MHC-I Conformers. J Cell Physiol 2016; 232:872-887. [DOI: 10.1002/jcp.25495] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 07/19/2016] [Indexed: 01/28/2023]
Affiliation(s)
- Hana Mahmutefendić
- Faculty of Medicine, Department of Physiology and Immunology; University of Rijeka; Rijeka Croatia
| | | | | | - Ljerka Karleuša
- Faculty of Medicine, Department of Physiology and Immunology; University of Rijeka; Rijeka Croatia
| | - Senka Maćešić
- Faculty of Engineering, Department of Mathematics, Physics, Foreign Languages and Kinesiology; University of Rijeka; Rijeka Croatia
| | - Frank Momburg
- Antigen Presentation & T/NK Cell Activation Group, Clinical Cooperation Unit Applied Tumor Immunity; German Cancer Research Center; Heidelberg Germany
| | - Pero Lučin
- Faculty of Medicine, Department of Physiology and Immunology; University of Rijeka; Rijeka Croatia
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Abstract
Transmissible spongiform encephalopathies (TSEs), or prion diseases, are fatal neurodegenerative disorders characterised by long incubation period, short clinical duration, and transmissibility to susceptible species. Neuronal loss, spongiform changes, gliosis and the accumulation in the brain of the misfolded version of a membrane-bound cellular prion protein (PrP(C)), termed PrP(TSE), are diagnostic markers of these diseases. Compelling evidence links protein misfolding and its accumulation with neurodegenerative changes. Accordingly, several mechanisms of prion-mediated neurotoxicity have been proposed. In this paper, we provide an overview of the recent knowledge on the mechanisms of neuropathogenesis, the neurotoxic PrP species and the possible therapeutic approaches to treat these devastating disorders.
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Lewis V, Johanssen VA, Crouch PJ, Klug GM, Hooper NM, Collins SJ. Prion protein "gamma-cleavage": characterizing a novel endoproteolytic processing event. Cell Mol Life Sci 2016; 73:667-83. [PMID: 26298290 PMCID: PMC11108375 DOI: 10.1007/s00018-015-2022-z] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Revised: 07/17/2015] [Accepted: 08/11/2015] [Indexed: 12/31/2022]
Abstract
The cellular prion protein (PrP(C)) is a ubiquitously expressed protein of currently unresolved but potentially diverse function. Of putative relevance to normal biological activity, PrP(C) is recognized to undergo both α- and β-endoproteolysis, producing the cleavage fragment pairs N1/C1 and N2/C2, respectively. Experimental evidence suggests the likelihood that these processing events serve differing cellular needs. Through the engineering of a C-terminal c-myc tag onto murine PrP(C), as well as the selective use of a far-C-terminal anti-PrP antibody, we have identified a new PrP(C) fragment, nominally 'C3', and elaborating existing nomenclature, 'γ-cleavage' as the responsible proteolysis. Our studies indicate that this novel γ-cleavage event can occur during transit through the secretory pathway after exiting the endoplasmic reticulum, and after PrP(C) has reached the cell surface, by a matrix metalloprotease. We found that C3 is GPI-anchored like other C-terminal and full length PrP(C) species, though it does not localize primarily at the cell surface, and is preferentially cleaved from an unglycosylated substrate. Importantly, we observed that C3 exists in diverse cell types as well as mouse and human brain tissue, and of possible pathogenic significance, γ-cleavage may increase in human prion diseases. Given the likely relevance of PrP(C) processing to both its normal function, and susceptibility to prion disease, the potential importance of this previously underappreciated and overlooked cleavage event warrants further consideration.
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Affiliation(s)
- Victoria Lewis
- Department of Medicine, RMH, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Vanessa A Johanssen
- Department of Pathology, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Peter J Crouch
- Department of Pathology, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Genevieve M Klug
- Department of Medicine, RMH, The University of Melbourne, Parkville, VIC, 3010, Australia
- The Australian National Creutzfeldt-Jakob Disease Registry, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Nigel M Hooper
- Institute of Brain, Behaviour and Mental Health, Faculty of Medical and Human Sciences, The University of Manchester, Manchester, M13 9PT, UK
| | - Steven J Collins
- Department of Medicine, RMH, The University of Melbourne, Parkville, VIC, 3010, Australia.
- The Australian National Creutzfeldt-Jakob Disease Registry, The University of Melbourne, Parkville, VIC, 3010, Australia.
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17
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Trafficking and degradation pathways in pathogenic conversion of prions and prion-like proteins in neurodegenerative diseases. Virus Res 2015; 207:146-54. [DOI: 10.1016/j.virusres.2015.01.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 10/01/2014] [Accepted: 01/22/2015] [Indexed: 11/20/2022]
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18
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Steinert JR. Prion protein as a mediator of synaptic transmission. Commun Integr Biol 2015; 8:e1063753. [PMID: 26478992 PMCID: PMC4594542 DOI: 10.1080/19420889.2015.1063753] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Revised: 06/11/2015] [Accepted: 06/12/2015] [Indexed: 10/31/2022] Open
Abstract
Neurodegenerative disorders are characterized by synaptic and neuronal dysfunction which precedes general neuronal loss and subsequent cognitive or behavioral anomalies. Although the exact early cellular signaling mechanisms involved in neurodegenerative diseases are largely unknown, a view is emerging that compromised synaptic function may underlie the initial steps in disease progression. Much recent research has been aimed at understanding these early underlying processes leading to dysfunctional synaptic signaling, as this knowledge could identify putative sites of interventions, which could potentially slow progression and delay onset of disease. We have recently reported that synaptic function in a Drosophila melanogaster model can be modulated by the presence of native mouse prion protein and this modulation is negatively affected by a mutation within the protein which is associated with the Gerstmann-Sträussler-Scheinker syndrome, a human form of prion disease. Indeed, wild-type prion protein facilitates synaptic release, whereas the mutated form induced diminished phenotypes. It is believed that together with the gain-of-function of neurotoxic misfolded prion signaling, the lack of prion protein contributes to the pathology in prion diseases. Therefore, our study investigated a potential endogenous role of prion protein in synaptic signaling, the lack of which could resemble a lack-of-function phenotype in prion disease.
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19
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Beckman D, Santos LE, Americo TA, Ledo JH, de Mello FG, Linden R. Prion Protein Modulates Monoaminergic Systems and Depressive-like Behavior in Mice. J Biol Chem 2015; 290:20488-98. [PMID: 26152722 DOI: 10.1074/jbc.m115.666156] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Indexed: 12/14/2022] Open
Abstract
We sought to examine interactions of the prion protein (PrP(C)) with monoaminergic systems due to: the role of PrP(C) in both Prion and Alzheimer diseases, which include clinical depression among their symptoms, the implication of monoamines in depression, and the hypothesis that PrP(C) serves as a scaffold for signaling systems. To that effect we compared both behavior and monoaminergic markers in wild type (WT) and PrP(C)-null (PrP(-/-)) mice. PrP(-/-) mice performed poorly when compared with WT in forced swimming, tail suspension, and novelty suppressed feeding tests, typical of depressive-like behavior, but not in the control open field nor rotarod motor tests; cyclic AMP responses to stimulation of D1 receptors by dopamine was selectively impaired in PrP(-/-) mice, and responses to serotonin, but not to norepinephrine, also differed between genotypes. Contents of dopamine, tyrosine hydroxylase, and the 5-HT5A serotonin receptor were increased in the cerebral cortex of PrP(-/-), as compared with WT mice. Microscopic colocalization, as well as binding in overlay assays were found of PrP(C) with both the 5HT5A and D1, but not D4 receptors. The data are consistent with the scaffolding of monoaminergic signaling modules by PrP(C), and may help understand the pathogenesis of clinical depression and neurodegenerative disorders.
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Affiliation(s)
| | | | | | - Jose H Ledo
- Instituto de Bioquímica Médica da UFRJ, Rio de Janeiro 21941-902, Brasil
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20
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Zafar S, Schmitz M, Younus N, Tahir W, Shafiq M, Llorens F, Ferrer I, Andéoletti O, Zerr I. Creutzfeldt-Jakob Disease Subtype-Specific Regional and Temporal Regulation of ADP Ribosylation Factor-1-Dependent Rho/MLC Pathway at Pre-Clinical Stage. J Mol Neurosci 2015; 56:329-48. [PMID: 25896910 DOI: 10.1007/s12031-015-0544-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Accepted: 03/09/2015] [Indexed: 10/23/2022]
Abstract
Small GTPases of the Arf family mainly activate the formation of coated carrier vesicles. We showed that class-I Arf1 interacts specifically with full length GPI-anchored cellular prion protein (PrP(C)). Several recent reports have also demonstrated a missing link between the endoplasmic reticulum and the Golgi-complex role for proper folding, but the exact molecular mechanism is not yet fully understood. In the present study, we identified and characterized the interactive role of Arf1 during PrP(C) intracellular distribution under pathophysiological conditions. PrP(C) interaction with Arf1 was investigated in cortical primary neuronal cultures of PrP(C) wild type and knockout mice (PrP(-/-)). Arf1 and PrP(C) co-binding affinity was confirmed using reverse co-immunoprecipitation, co-localization affinity using confocal laser-scanning microscopy. Treatment with brefeldin-A modulated Arf1 expression and resulted in down-regulation and redistribution of PrP(C) into cytosolic region. In the pre-symptomatic stage of the disease, Arf1 expression was significantly downregulated in the frontal cortex in tg340 mice expressing about fourfold of human PrP-M129 with PrP null background that had been inoculated with human sCJD MM1 brain tissue homogenates (sCJD MM1 mice). In addition, the frontal cortex of CJD human brain demonstrated significant binding capacity of Arf1 protein using co-immunoprecipitation analysis. We also examined Arf1 expression in the brain of CJD patients with the subtypes MM1 and VV2 and found that it was regulated in a region-specific manner. In the frontal cortex, Arf1 expression was not significantly changed in either MM1 or VV2 subtype. Interestingly, Arf1 expression was significantly reduced in the cerebellum in both subtypes as compared to controls. Furthermore, we observed altered RhoA activity, which in turn affects myosin light-chain (MLC) phosphorylation and Arf1-dependent PI3K pathway. Together, our findings underscore a key early symptomatic role of Arf1 in neurodegeneration. Targeting the Arf/Rho/MLC signaling axis might be a promising strategy to uncover the missing link which probably influences disease progression and internal homeostasis of misfolded proteins.
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Affiliation(s)
- Saima Zafar
- Department of Neurology, Clinical Dementia Center and DZNE, Georg-August University, University Medical Center Goettingen (UMG), Robert-Koch-Str. 40, 37075, Goettingen, Germany,
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21
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Hadži S, Ondračka A, Jerala R, Hafner‐Bratkovič I. Pathological mutations H187R and E196K facilitate subdomain separation and prion protein conversion by destabilization of the native structure. FASEB J 2014; 29:882-93. [DOI: 10.1096/fj.14-255646] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- San Hadži
- Department of BiotechnologyNational Institute of ChemistryLjubljanaSlovenia
| | - Andrej Ondračka
- Department of BiotechnologyNational Institute of ChemistryLjubljanaSlovenia
| | - Roman Jerala
- Department of BiotechnologyNational Institute of ChemistryLjubljanaSlovenia
- EN‐FIST Centre of ExcellenceLjubljanaSlovenia
| | - Iva Hafner‐Bratkovič
- Department of BiotechnologyNational Institute of ChemistryLjubljanaSlovenia
- EN‐FIST Centre of ExcellenceLjubljanaSlovenia
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22
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Intracellular processing of disease-associated α-synuclein in the human brain suggests prion-like cell-to-cell spread. Neurobiol Dis 2014; 69:76-92. [DOI: 10.1016/j.nbd.2014.05.020] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Revised: 04/29/2014] [Accepted: 05/17/2014] [Indexed: 01/13/2023] Open
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23
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Robinson SW, Nugent ML, Dinsdale D, Steinert JR. Prion protein facilitates synaptic vesicle release by enhancing release probability. Hum Mol Genet 2014; 23:4581-96. [PMID: 24722203 PMCID: PMC4119408 DOI: 10.1093/hmg/ddu171] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The cellular prion protein (PrP(C)) has been implicated in several neurodegenerative diseases as a result of protein misfolding. In humans, prion disease occurs typically with a sporadic origin where uncharacterized mechanisms induce spontaneous PrP(C) misfolding leading to neurotoxic PrP-scrapie formation (PrP(SC)). The consequences of misfolded PrP(C) signalling are well characterized but little is known about the physiological roles of PrP(C) and its involvement in disease. Here we investigated wild-type PrP(C) signalling in synaptic function as well as the effects of a disease-relevant mutation within PrP(C) (proline-to-leucine mutation at codon 101). Expression of wild-type PrP(C) at the Drosophila neuromuscular junction leads to enhanced synaptic responses as detected in larger miniature synaptic currents which are caused by enlarged presynaptic vesicles. The expression of the mutated PrP(C) leads to reduction of both parameters compared with wild-type PrP(C). Wild-type PrP(C) enhances synaptic release probability and quantal content but reduces the size of the ready-releasable vesicle pool. Partially, these changes are not detectable following expression of the mutant PrP(C). A behavioural test revealed that expression of either protein caused an increase in locomotor activities consistent with enhanced synaptic release and stronger muscle contractions. Both proteins were sensitive to proteinase digestion. These data uncover new functions of wild-type PrP(C) at the synapse with a disease-relevant mutation in PrP(C) leading to diminished functional phenotypes. Thus, our data present essential new information possibly related to prion pathogenesis in which a functional synaptic role of PrP(C) is compromised due to its advanced conversion into PrP(SC) thereby creating a lack-of-function scenario.
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Affiliation(s)
- Susan W Robinson
- MRC Toxicology Unit, Hodgkin Building, Lancaster Road, Leicester LE1 9HN, UK
| | - Marie L Nugent
- MRC Toxicology Unit, Hodgkin Building, Lancaster Road, Leicester LE1 9HN, UK Department of Genetics, University of Leicester, University Road, Leicester LE1 7RH, UK
| | - David Dinsdale
- MRC Toxicology Unit, Hodgkin Building, Lancaster Road, Leicester LE1 9HN, UK
| | - Joern R Steinert
- MRC Toxicology Unit, Hodgkin Building, Lancaster Road, Leicester LE1 9HN, UK
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24
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Miyagawa-Yamaguchi A, Kotani N, Honke K. Expressed glycosylphosphatidylinositol-anchored horseradish peroxidase identifies co-clustering molecules in individual lipid raft domains. PLoS One 2014; 9:e93054. [PMID: 24671047 PMCID: PMC3966864 DOI: 10.1371/journal.pone.0093054] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Accepted: 03/02/2014] [Indexed: 11/18/2022] Open
Abstract
Lipid rafts that are enriched in glycosylphosphatidylinositol (GPI)-anchored proteins serve as a platform for important biological events. To elucidate the molecular mechanisms of these events, identification of co-clustering molecules in individual raft domains is required. Here we describe an approach to this issue using the recently developed method termed enzyme-mediated activation of radical source (EMARS), by which molecules in the vicinity within 300 nm from horseradish peroxidase (HRP) set on the probed molecule are labeled. GPI-anchored HRP fusion proteins (HRP-GPIs), in which the GPI attachment signals derived from human decay accelerating factor and Thy-1 were separately connected to the C-terminus of HRP, were expressed in HeLa S3 cells, and the EMARS reaction was catalyzed by these expressed HRP-GPIs under a living condition. As a result, these different HRP-GPIs had differences in glycosylation and localization and formed distinct clusters. This novel approach distinguished molecular clusters associated with individual GPI-anchored proteins, suggesting that it can identify co-clustering molecules in individual raft domains.
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Affiliation(s)
- Arisa Miyagawa-Yamaguchi
- Kochi System Glycobiology Center, Kochi University Medical School, Nankoku, Kochi, Japan
- Center for Innovate and Translational Medicine, Kochi University Medical School, Nankoku, Kochi, Japan
| | - Norihiro Kotani
- Kochi System Glycobiology Center, Kochi University Medical School, Nankoku, Kochi, Japan
- Center for Innovate and Translational Medicine, Kochi University Medical School, Nankoku, Kochi, Japan
- Department of Biochemistry, Saitama Medical University, Iruma-gun, Saitama, Japan
| | - Koichi Honke
- Kochi System Glycobiology Center, Kochi University Medical School, Nankoku, Kochi, Japan
- Center for Innovate and Translational Medicine, Kochi University Medical School, Nankoku, Kochi, Japan
- Department of Biochemistry, Kochi University Medical School, Nankoku, Kochi, Japan
- * E-mail:
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25
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Karnik R, Ludlow MJ, Abuarab N, Smith AJ, Hardy MEL, Elliott DJS, Sivaprasadarao A. Endocytosis of HERG is clathrin-independent and involves arf6. PLoS One 2013; 8:e85630. [PMID: 24392021 PMCID: PMC3877390 DOI: 10.1371/journal.pone.0085630] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 12/05/2013] [Indexed: 01/02/2023] Open
Abstract
The hERG potassium channel is critical for repolarisation of the cardiac action potential. Reduced expression of hERG at the plasma membrane, whether caused by hereditary mutations or drugs, results in long QT syndrome and increases the risk of ventricular arrhythmias. Thus, it is of fundamental importance to understand how the density of this channel at the plasma membrane is regulated. We used antibodies to an extracellular native or engineered epitope, in conjunction with immunofluorescence and ELISA, to investigate the mechanism of hERG endocytosis in recombinant cells and validated the findings in rat neonatal cardiac myocytes. The data reveal that this channel undergoes rapid internalisation, which is inhibited by neither dynasore, an inhibitor of dynamin, nor a dominant negative construct of Rab5a, into endosomes that are largely devoid of the transferrin receptor. These results support a clathrin-independent mechanism of endocytosis and exclude involvement of dynamin-dependent caveolin and RhoA mechanisms. In agreement, internalised hERG displayed marked overlap with glycosylphosphatidylinositol-anchored GFP, a clathrin-independent cargo. Endocytosis was significantly affected by cholesterol extraction with methyl-β-cyclodextrin and inhibition of Arf6 function with dominant negative Arf6-T27N-eGFP. Taken together, we conclude that hERG undergoes clathrin-independent endocytosis via a mechanism involving Arf6.
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Affiliation(s)
- Rucha Karnik
- School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
| | - Melanie J. Ludlow
- School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
- Faculty of Biological Sciences, Multidisciplinary Cardiovascular Centre, University of Leeds, Leeds, United Kingdom
| | - Nada Abuarab
- School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
| | - Andrew J. Smith
- School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
| | | | | | - Asipu Sivaprasadarao
- School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
- Faculty of Biological Sciences, Multidisciplinary Cardiovascular Centre, University of Leeds, Leeds, United Kingdom
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26
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Pocanschi CL, Ehsani S, Mehrabian M, Wille H, Reginold W, Trimble WS, Wang H, Yee A, Arrowsmith CH, Bozóky Z, Kay LE, Forman-Kay JD, Rini JM, Schmitt-Ulms G. The ZIP5 ectodomain co-localizes with PrP and may acquire a PrP-like fold that assembles into a dimer. PLoS One 2013; 8:e72446. [PMID: 24039764 PMCID: PMC3765157 DOI: 10.1371/journal.pone.0072446] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Accepted: 07/18/2013] [Indexed: 01/11/2023] Open
Abstract
The cellular prion protein (PrP(C)) was recently observed to co-purify with members of the LIV-1 subfamily of ZIP zinc transporters (LZTs), precipitating the surprising discovery that the prion gene family descended from an ancestral LZT gene. Here, we compared the subcellular distribution and biophysical characteristics of LZTs and their PrP-like ectodomains. When expressed in neuroblastoma cells, the ZIP5 member of the LZT subfamily was observed to be largely directed to the same subcellular locations as PrP(C) and both proteins were seen to be endocytosed through vesicles decorated with the Rab5 marker protein. When recombinantly expressed, the PrP-like domain of ZIP5 could be obtained with yields and levels of purity sufficient for structural analyses but it tended to aggregate, thereby precluding attempts to study its structure. These obstacles were overcome by moving to a mammalian cell expression system. The subsequent biophysical characterization of a homogeneous preparation of the ZIP5 PrP-like ectodomain shows that this protein acquires a dimeric, largely globular fold with an α-helical content similar to that of mammalian PrP(C). The use of a mammalian cell expression system also allowed for the expression and purification of stable preparations of Takifugu rubripes PrP-1, thereby overcoming a key hindrance to high-resolution work on a fish PrP(C).
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Affiliation(s)
- Cosmin L. Pocanschi
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada
| | - Sepehr Ehsani
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Mohadeseh Mehrabian
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Holger Wille
- Department of Biochemistry and Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
| | - William Reginold
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - William S. Trimble
- Program in Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Hansen Wang
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada
| | - Adelinda Yee
- Structural Genomics Consortium, Toronto, Ontario, Canada
| | | | - Zoltán Bozóky
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
- Molecular Structure and Function Program, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Lewis E. Kay
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
- Molecular Structure and Function Program, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Julie D. Forman-Kay
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
- Molecular Structure and Function Program, Hospital for Sick Children, Toronto, Ontario, Canada
| | - James M. Rini
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Gerold Schmitt-Ulms
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
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27
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Forget KJ, Tremblay G, Roucou X. p53 Aggregates penetrate cells and induce the co-aggregation of intracellular p53. PLoS One 2013; 8:e69242. [PMID: 23844254 PMCID: PMC3700952 DOI: 10.1371/journal.pone.0069242] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Accepted: 06/12/2013] [Indexed: 12/01/2022] Open
Abstract
Prion diseases are unique pathologies in which the infectious particles are prions, a protein aggregate. The prion protein has many particular features, such as spontaneous aggregation, conformation transmission to other native PrP proteins and transmission from an individual to another. Protein aggregation is now frequently associated to many human diseases, for example Alzheimer’s disease, Parkinson’s disease or type 2 diabetes. A few proteins associated to these conformational diseases are part of a new category of proteins, called prionoids: proteins that share some, but not all, of the characteristics associated with prions. The p53 protein, a transcription factor that plays a major role in cancer, has recently been suggested to be a possible prionoid. The protein has been shown to accumulate in multiple cancer cell types, and its aggregation has also been reproduced in vitro by many independent groups. These observations suggest a role for p53 aggregates in cancer development. This study aims to test the «prion-like» features of p53. Our results show in vitro aggregation of the full length and N-terminally truncated protein (p53C), and penetration of these aggregates into cells. According to our findings, the aggregates enter cells using macropinocytosis, a non-specific pathway of entry. Lastly, we also show that once internalized by the cell, p53C aggregates can co-aggregate with endogenous p53 protein. Together, these findings suggest prion-like characteristics for p53 protein, based on the fact that p53 can spontaneously aggregate, these aggregates can penetrate cells and co-aggregate with cellular p53.
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Affiliation(s)
- Karolyn J. Forget
- Département de Biochimie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Guillaume Tremblay
- Département de Biochimie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Xavier Roucou
- Département de Biochimie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Québec, Canada
- * E-mail:
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28
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Patel A, Vasiljevic S, Jones IM. Unique structural properties associated with mouse prion Δ105-125 protein. Prion 2013; 7:235-43. [PMID: 23764837 PMCID: PMC3783109 DOI: 10.4161/pri.24429] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Murine prion protein deleted for residues 105-125 is intrinsically neurotoxic and mediates a TSE-like phenotype in transgenic mice. Equivalent and overlapping deletions were expressed in E.coli, purified and analyzed. Among mutants spanning the region 95-135, a construct lacking solely residues 105-125 had distinct properties when compared with the full-length prion protein 23-231 or other deletions. This distinction was also apparent followed expression in eukaryotic cells. Unlike the full-length protein, all deletion mutants failed to bind to synthetic membranes in vitro. These data suggest a novel structure for the 105-125 deleted variant that may relate to its biological properties.
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Affiliation(s)
- Avnish Patel
- School of Biological Sciences, University of Reading, Reading, United Kingdom
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29
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Cellular aspects of prion replication in vitro. Viruses 2013; 5:374-405. [PMID: 23340381 PMCID: PMC3564126 DOI: 10.3390/v5010374] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Revised: 01/07/2013] [Accepted: 01/16/2013] [Indexed: 12/19/2022] Open
Abstract
Prion diseases or transmissible spongiform encephalopathies (TSEs) are fatal neurodegenerative disorders in mammals that are caused by unconventional agents predominantly composed of aggregated misfolded prion protein (PrP). Prions self-propagate by recruitment of host-encoded PrP into highly ordered β-sheet rich aggregates. Prion strains differ in their clinical, pathological and biochemical characteristics and are likely to be the consequence of distinct abnormal prion protein conformers that stably replicate their alternate states in the host cell. Understanding prion cell biology is fundamental for identifying potential drug targets for disease intervention. The development of permissive cell culture models has greatly enhanced our knowledge on entry, propagation and dissemination of TSE agents. However, despite extensive research, the precise mechanism of prion infection and potential strain effects remain enigmatic. This review summarizes our current knowledge of the cell biology and propagation of prions derived from cell culture experiments. We discuss recent findings on the trafficking of cellular and pathologic PrP, the potential sites of abnormal prion protein synthesis and potential co-factors involved in prion entry and propagation.
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30
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Vila-Viçosa D, Campos SRR, Baptista AM, Machuqueiro M. Reversibility of prion misfolding: insights from constant-pH molecular dynamics simulations. J Phys Chem B 2012; 116:8812-21. [PMID: 22803931 DOI: 10.1021/jp3034837] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The prion protein (PrP) is the cause of a group of diseases known as transmissible spongiform encephalopathies (TSEs). Creutzfeldt-Jakob disease and bovine spongiform encephalopathy are examples of TSEs. Although the normal form of PrP (PrP(C)) is monomeric and soluble, it can misfold into a pathogenic form (PrP(Sc)) that has a high content of β-structure and can aggregate forming amyloid fibrils. The mechanism of conversion of PrP(C) into PrP(Sc) is not known but different triggers have been proposed. It can be catalyzed by a PrP(Sc) sample, or it can be induced by an external factor, such as low pH. The pH effect on the structure of PrP was recently studied by computational methods [Campos et al. J. Phys. Chem. B 2010, 114, 12692-12700], and an evident trend of loss of helical structure was observed with pH decrease, together with a gain of β-structures. In particular, one simulation at pH 2 showed an evident misfolding transition. The main goal of the present work was to study the effects of a change in pH to 7 in several transient conformations of this simulation, in order to draw some conclusions about the reversibility of PrP misfolding. Although the most significant effect caused by the change of pH to 7 was a global stabilization of the protein structure, we could also observe that some conformational transitions induced by pH 2 were reversible in many of our simulations, namely those started from the early moments of the misfolding transition. This observation is in good agreement with experiments showing that, even at pH as low as 1.7, it is possible to revert the misfolding process [Bjorndahl et al. Biochemistry 2011, 50, 1162-1173].
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Affiliation(s)
- Diogo Vila-Viçosa
- Centro de Química e Bioquímica e Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal
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31
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Pflanzner T, Petsch B, André-Dohmen B, Müller-Schiffmann A, Tschickardt S, Weggen S, Stitz L, Korth C, Pietrzik CU. Cellular prion protein participates in amyloid-β transcytosis across the blood-brain barrier. J Cereb Blood Flow Metab 2012; 32:628-32. [PMID: 22293988 PMCID: PMC3318156 DOI: 10.1038/jcbfm.2012.7] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Revised: 11/30/2011] [Accepted: 12/25/2011] [Indexed: 12/21/2022]
Abstract
The blood-brain barrier (BBB) facilitates amyloid-β (Aβ) exchange between the blood and the brain. Here, we found that the cellular prion protein (PrP(c)), a putative receptor implicated in mediating Aβ neurotoxicity in Alzheimer's disease (AD), participates in Aβ transcytosis across the BBB. Using an in vitro BBB model, [(125)I]-Aβ(1-40) transcytosis was reduced by genetic knockout of PrP(c) or after addition of a competing PrP(c)-specific antibody. Furthermore, we provide evidence that PrP(c) is expressed in endothelial cells and, that monomeric Aβ(1-40) binds to PrP(c). These observations provide new mechanistic insights into the role of PrP(c) in AD.
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Affiliation(s)
- Thorsten Pflanzner
- Molecular Neurodegeneration, Institute of Pathobiochemistry, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
| | - Benjamin Petsch
- Institute of Immunology, Friedrich-Loeffler-Institut, Tuebingen, Germany
| | - Bettina André-Dohmen
- Molecular Neurodegeneration, Institute of Pathobiochemistry, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
| | | | - Sabrina Tschickardt
- Molecular Neurodegeneration, Institute of Pathobiochemistry, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
| | - Sascha Weggen
- Department of Neuropathology, Heinrich-Heine-University, Düsseldorf, Germany
| | - Lothar Stitz
- Institute of Immunology, Friedrich-Loeffler-Institut, Tuebingen, Germany
| | - Carsten Korth
- Department of Neuropathology, Heinrich-Heine-University, Düsseldorf, Germany
| | - Claus U Pietrzik
- Molecular Neurodegeneration, Institute of Pathobiochemistry, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
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da Fonseca A, Romão L, Amaral R, Assad Kahn S, Lobo D, Martins S, Marcondes de Souza J, Moura-Neto V, Lima F. Microglial stress inducible protein 1 promotes proliferation and migration in human glioblastoma cells. Neuroscience 2012; 200:130-41. [DOI: 10.1016/j.neuroscience.2011.10.025] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Revised: 10/10/2011] [Accepted: 10/14/2011] [Indexed: 12/26/2022]
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Yamasaki T, Suzuki A, Shimizu T, Watarai M, Hasebe R, Horiuchi M. Characterization of intracellular localization of PrP(Sc) in prion-infected cells using a mAb that recognizes the region consisting of aa 119-127 of mouse PrP. J Gen Virol 2011; 93:668-680. [PMID: 22090211 DOI: 10.1099/vir.0.037101-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Generation of an abnormal isoform of the prion protein (PrP(Sc)) is a key aspect of the propagation of prions. Elucidation of the intracellular localization of PrP(Sc) in prion-infected cells facilitates the understanding of the cellular mechanism of prion propagation. However, technical improvement in PrP(Sc)-specific detection is required for precise analysis. Here, we show that the mAb 132, which recognizes the region adjacent to the most amyloidogenic region of PrP, is useful for PrP(Sc)-specific detection by immunofluorescence assay in cells pre-treated with guanidine thiocyanate. Extensive analysis of the intracellular localization of PrP(Sc) in prion-infected cells using mAb 132 revealed the presence of PrP(Sc) throughout endocytic compartments. In particular, some of the granular PrP(Sc) signals that were clustered at peri-nuclear regions appeared to be localized in an endocytic recycling compartment through which exogenously loaded transferrin, shiga and cholera toxin B subunits were transported. The granular PrP(Sc) signals at peri-nuclear regions were dispersed to the peripheral regions including the plasma membrane during incubation at 20 °C, at which temperature transport from the plasma membrane to peri-nuclear regions was impaired. Conversely, dispersed PrP(Sc) signals appeared to return to peri-nuclear regions within 30 min during subsequent incubation at 37 °C, following which PrP(Sc) at peri-nuclear regions appeared to redisperse again to peripheral regions over the next 30 min incubation. These results suggest that PrP(Sc) is dynamically transported along with the membrane trafficking machinery of cells and that at least some PrP(Sc) circulates between peri-nuclear and peripheral regions including the plasma membrane via an endocytic recycling pathway.
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Affiliation(s)
- Takeshi Yamasaki
- Laboratory of Veterinary Hygiene, Graduate School of Veterinary Medicine, Hokkaido University, Kita 18, Nishi 9, Kita-ku, Sapporo 060-0818, Japan
| | - Akio Suzuki
- Laboratory of Veterinary Hygiene, Graduate School of Veterinary Medicine, Hokkaido University, Kita 18, Nishi 9, Kita-ku, Sapporo 060-0818, Japan
| | - Takeshi Shimizu
- Department of Molecular Infectiology, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chiba 260-8670, Japan
| | - Masahisa Watarai
- Department of Veterinary Public Health, Faculty of Agriculture, Yamaguchi University, 1677-1 Yoshida, Yamaguchi 753-8515, Japan
| | - Rie Hasebe
- Laboratory of Veterinary Hygiene, Graduate School of Veterinary Medicine, Hokkaido University, Kita 18, Nishi 9, Kita-ku, Sapporo 060-0818, Japan
| | - Motohiro Horiuchi
- Laboratory of Veterinary Hygiene, Graduate School of Veterinary Medicine, Hokkaido University, Kita 18, Nishi 9, Kita-ku, Sapporo 060-0818, Japan
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Westergard L, Turnbaugh JA, Harris DA. A naturally occurring C-terminal fragment of the prion protein (PrP) delays disease and acts as a dominant-negative inhibitor of PrPSc formation. J Biol Chem 2011; 286:44234-44242. [PMID: 22025612 DOI: 10.1074/jbc.m111.286195] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The cellular prion protein (PrPC) undergoes constitutive proteolytic cleavage between residues 111/112 to yield a soluble N-terminal fragment (N1) and a membrane-anchored C-terminal fragment (C1). The C1 fragment represents the major proteolytic fragment of PrPC in brain and several cell types. To explore the role of C1 in prion disease, we generated Tg(C1) transgenic mice expressing this fragment (PrP(Δ23-111)) in the presence and absence of endogenous PrP. In contrast to several other N-terminally deleted forms of PrP, the C1 fragment does not cause a spontaneous neurological disease in the absence of endogenous PrP. Tg(C1) mice inoculated with scrapie prions remain healthy and do not accumulate protease-resistant PrP, demonstrating that C1 is not a substrate for conversion to PrPSc (the disease-associated isoform). Interestingly, Tg(C1) mice co-expressing C1 along with wild-type PrP (either endogenous or encoded by a second transgene) become ill after scrapie inoculation, but with a dramatically delayed time course compared with mice lacking C1. In addition, accumulation of PrPSc was markedly slowed in these animals. Similar effects were produced by a shorter C-terminal fragment of PrP(Δ23-134). These results demonstrate that C1 acts as dominant-negative inhibitor of PrPSc formation and accumulation of neurotoxic forms of PrP. Thus, C1, a naturally occurring fragment of PrPC, might play a modulatory role during the course of prion diseases. In addition, enhancing production of C1, or exogenously administering this fragment, represents a potential therapeutic strategy for the treatment of prion diseases.
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Affiliation(s)
- Laura Westergard
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Jessie A Turnbaugh
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118
| | - David A Harris
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118.
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Caetano FA, Beraldo FH, Hajj GNM, Guimaraes AL, Jürgensen S, Wasilewska-Sampaio AP, Hirata PHF, Souza I, Machado CF, Wong DYL, De Felice FG, Ferreira ST, Prado VF, Rylett RJ, Martins VR, Prado MAM. Amyloid-beta oligomers increase the localization of prion protein at the cell surface. J Neurochem 2011; 117:538-53. [PMID: 21352228 DOI: 10.1111/j.1471-4159.2011.07225.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
In Alzheimer's disease, the amyloid-β peptide (Aβ) interacts with distinct proteins at the cell surface to interfere with synaptic communication. Recent data have implicated the prion protein (PrP(C)) as a putative receptor for Aβ. We show here that Aβ oligomers signal in cells in a PrP(C)-dependent manner, as might be expected if Aβ oligomers use PrP(C) as a receptor. Immunofluorescence, flow cytometry and cell surface protein biotinylation experiments indicated that treatment with Aβ oligomers, but not monomers, increased the localization of PrP(C) at the cell surface in cell lines. These results were reproduced in hippocampal neuronal cultures by labeling cell surface PrP(C). In order to understand possible mechanisms involved with this effect of Aβ oligomers, we used live cell confocal and total internal reflection microscopy in cell lines. Aβ oligomers inhibited the constitutive endocytosis of PrP(C), but we also found that after Aβ oligomer-treatment PrP(C) formed more clusters at the cell surface, suggesting the possibility of multiple effects of Aβ oligomers. Our experiments show for the first time that Aβ oligomers signal in a PrP(C)-dependent way and that they can affect PrP(C) trafficking, increasing its localization at the cell surface.
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Affiliation(s)
- Fabiana A Caetano
- J. Allyn Taylor Centre for Cell Biology, Robarts Research Institute, University of Western Ontario, London, Ontario, Canada
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Bate C, Williams A. Monoacylated cellular prion protein modifies cell membranes, inhibits cell signaling, and reduces prion formation. J Biol Chem 2011; 286:8752-8. [PMID: 21212283 DOI: 10.1074/jbc.m110.186833] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Prion diseases occur following the conversion of the cellular prion protein (PrP(C)) into a disease related, protease-resistant isoform (PrP(Sc)). In these studies, a cell painting technique was used to introduce PrP(C) to prion-infected neuronal cell lines (ScGT1, ScN2a, or SMB cells). The addition of PrP(C) resulted in increased PrP(Sc) formation that was preceded by an increase in the cholesterol content of cell membranes and increased activation of cytoplasmic phospholipase A(2) (cPLA(2)). In contrast, although PrP(C) lacking one of the two acyl chains from its glycosylphosphatidylinositol (GPI) anchor (PrP(C)-G-lyso-PI) bound readily to cells, it did not alter the amount of cholesterol in cell membranes, was not found within detergent-resistant membranes (lipid rafts), and did not activate cPLA(2). It remained within cells for longer than PrP(C) with a conventional GPI anchor and was not converted to PrP(Sc). Moreover, the addition of high amounts of PrP(C)-G-lyso-PI displaced cPLA(2) from PrP(Sc)-containing lipid rafts, reduced the activation of cPLA(2), and reduced PrP(Sc) formation in all three cell lines. In addition, ScGT1 cells treated with PrP(C)-G-lyso-PI did not transmit infection following intracerebral injection to mice. We propose that that the chemical composition of the GPI anchor attached to PrP(C) modified the local membrane microenvironments that control cell signaling, the fate of PrP(C), and hence PrP(Sc) formation. In addition, our observations raise the possibility that pharmacological modification of GPI anchors might constitute a novel therapeutic approach to prion diseases.
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Affiliation(s)
- Clive Bate
- Department of Pathology and Infectious Diseases, Royal Veterinary College, Hawkshead Lane, North Mymms, Hertfordshire AL9 7TA, United Kingdom.
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Possible involvement of calpain-like activity in normal processing of cellular prion protein. Neurosci Lett 2010; 490:150-5. [PMID: 21193014 DOI: 10.1016/j.neulet.2010.12.046] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2010] [Revised: 12/17/2010] [Accepted: 12/19/2010] [Indexed: 11/21/2022]
Abstract
Time-lapse imaging analysis was previously used to show that spontaneous proteolysis of PrP(C), which is fluorescence-labeled at both NH(2)- and COOH-termini, occurred in mouse neuroblastoma neuro2a (N2a) cells susceptible to PrP(Sc). We demonstrated that, unlike other protease inhibitors, a calpain inhibitor, calpastatin, drastically inhibited endoproteolysis of PrP(C), as observed with time-lapse imaging in living cells, suggesting calpain-like activity. Calpastatin also inhibited cleavage of endogenous PrP(C), and unprocessed molecules and the double-labeled PrP(C) accumulated around the perinuclear region. The molecular weight of PrP(C) fragments generated by spontaneous proteolysis was identical to those produced when PrP(C) synthesized in vitro was exposed to exogenous calpain. These results suggest that a calpain-like activity mediates normal processing of PrP(C) in N2a cells.
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Silva JL, Vieira TCRG, Gomes MPB, Rangel LP, Scapin SMN, Cordeiro Y. Experimental approaches to the interaction of the prion protein with nucleic acids and glycosaminoglycans: Modulators of the pathogenic conversion. Methods 2010; 53:306-17. [PMID: 21145399 DOI: 10.1016/j.ymeth.2010.12.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2010] [Accepted: 12/02/2010] [Indexed: 11/17/2022] Open
Abstract
The concept that transmissible spongiform encephalopathies (TSEs) are caused only by proteins has changed the traditional paradigm that disease transmission is due solely to an agent that carries genetic information. The central hypothesis for prion diseases proposes that the conversion of a cellular prion protein (PrP(C)) into a misfolded, β-sheet-rich isoform (PrP(Sc)) accounts for the development of (TSE). There is substantial evidence that the infectious material consists chiefly of a protein, PrP(Sc), with no genomic coding material, unlike a virus particle, which has both. However, prions seem to have other partners that chaperone their activities in converting the PrP(C) into the disease-causing isoform. Nucleic acids (NAs) and glycosaminoglycans (GAGs) are the most probable accomplices of prion conversion. Here, we review the recent experimental approaches that have been employed to characterize the interaction of prion proteins with nucleic acids and glycosaminoglycans. A PrP recognizes many nucleic acids and GAGs with high affinities, and this seems to be related to a pathophysiological role for this interaction. A PrP binds nucleic acids and GAGs with structural selectivity, and some PrP:NA complexes can become proteinase K-resistant, undergoing amyloid oligomerization and conversion to a β-sheet-rich structure. These results are consistent with the hypothesis that endogenous polyanions (such as NAs and GAGs) may accelerate the rate of prion disease progression by acting as scaffolds or lattices that mediate the interaction between PrP(C) and PrP(Sc) molecules. In addition to a still-possible hypothesis that nucleic acids and GAGs, especially those from the host, may modulate the conversion, the recent structural characterization of the complexes has raised the possibility of developing new diagnostic and therapeutic strategies.
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Affiliation(s)
- Jerson L Silva
- Centro Nacional de Ressonância Magnética Nuclear Jiri Jonas, Instituto de Bioquímica Médica, Instituto Nacional de Ciência e Tecnologia de Biologia Estrutural e Bioimagem, Brazil.
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Takahashi RH, Tobiume M, Sato Y, Sata T, Gouras GK, Takahashi H. Accumulation of cellular prion protein within dystrophic neurites of amyloid plaques in the Alzheimer's disease brain. Neuropathology 2010; 31:208-14. [PMID: 21062360 DOI: 10.1111/j.1440-1789.2010.01158.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Amyloid plaques, a well-known hallmark of Alzheimer's disease (AD), are formed by aggregated β-amyloid (Aβ). The cellular prion protein (PrPc) accumulates concomitantly with Aβ in amyloid plaques. One type of amyloid plaque, classified as a neuritic plaque, is composed of an amyloid core and surrounding dystrophic neurites. PrPc immunoreactivity reminiscent of dystrophic neurites is observed in neuritic plaques. Proteinase K treatment prior to immunohistochemistry removes PrPc immunoreactivity from amyloid plaques, whereas Aβ immunoreactivity is enhanced by this treatment. In the present study, we used a chemical pretreatment by a sarkosyl solution (0.1% sarkosyl, 75 mM NaOH, 2% NaCl), instead of proteinase K treatment, to evaluate PrPc accumulation within amyloid plaques. Since PrPc within amyloid plaques is removed by this chemical pretreatment, we can recognize that the PrP species deposits within amyloid plaques were PrPc. We could observe that PrPc accumulation in dystrophic neurites occurred differently compared with Aβ or hyperphosphorylated tau aggregation in the AD brain. These results could support the hypothesis that PrPc accumulation in dystrophic neurites reflects a response to impairments in cellular degradation, endocytosis, or transport mechanisms associated with AD rather than a non-specific cross-reactivity between PrPc and aggregated Aβ or tau.
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Affiliation(s)
- Reisuke H Takahashi
- Department of Anatomic Pathology, Tokyo Medical University, Shinjuku-ku, Tokyo, Japan.
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40
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Beraldo FH, Arantes CP, Santos TG, Machado CF, Roffe M, Hajj GN, Lee KS, Magalhães AC, Caetano FA, Mancini GL, Lopes MH, Américo TA, Magdesian MH, Ferguson SSG, Linden R, Prado MAM, Martins VR. Metabotropic glutamate receptors transduce signals for neurite outgrowth after binding of the prion protein to laminin γ1 chain. FASEB J 2010; 25:265-79. [PMID: 20876210 DOI: 10.1096/fj.10-161653] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The prion protein (PrP(C)) is highly expressed in the nervous system, and its abnormal conformer is associated with prion diseases. PrP(C) is anchored to cell membranes by glycosylphosphatidylinositol, and transmembrane proteins are likely required for PrP(C)-mediated intracellular signaling. Binding of laminin (Ln) to PrP(C) modulates neuronal plasticity and memory. We addressed signaling pathways triggered by PrP(C)-Ln interaction in order to identify transmembrane proteins involved in the transduction of PrP(C)-Ln signals. The Ln γ1-chain peptide, which contains the Ln binding site for PrP(C), induced neuritogenesis through activation of phospholipase C (PLC), Ca(2+) mobilization from intracellular stores, and protein kinase C and extracellular signal-regulated kinase (ERK1/2) activation in primary cultures of neurons from wild-type, but not PrP(C)-null mice. Phage display, coimmunoprecipitation, and colocalization experiments showed that group I metabotropic glutamate receptors (mGluR1/5) associate with PrP(C). Expression of either mGluR1 or mGluR5 in HEK293 cells reconstituted the signaling pathways mediated by PrP(C)-Ln γ1 peptide interaction. Specific inhibitors of these receptors impaired PrP(C)-Ln γ1 peptide-induced signaling and neuritogenesis. These data show that group I mGluRs are involved in the transduction of cellular signals triggered by PrP(C)-Ln, and they support the notion that PrP(C) participates in the assembly of multiprotein complexes with physiological functions on neurons.
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Affiliation(s)
- Flavio H Beraldo
- Ludwig Institute for Cancer Research, Hospital Alemão Oswaldo Cruz, São Paulo, Brazil
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Campos SRR, Machuqueiro M, Baptista AM. Constant-pH Molecular Dynamics Simulations Reveal a β-Rich Form of the Human Prion Protein. J Phys Chem B 2010; 114:12692-700. [DOI: 10.1021/jp104753t] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Sara R. R. Campos
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, EAN, 2780-157 Oeiras, Portugal
| | - Miguel Machuqueiro
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, EAN, 2780-157 Oeiras, Portugal
| | - António M. Baptista
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, EAN, 2780-157 Oeiras, Portugal
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Bate C, Tayebi M, Williams A. Glycosylphosphatidylinositol anchor analogues sequester cholesterol and reduce prion formation. J Biol Chem 2010; 285:22017-26. [PMID: 20427265 DOI: 10.1074/jbc.m110.108548] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
A hallmark of prion diseases is the conversion of the host-encoded prion protein (PrP(C) where C is cellular) into an alternatively folded, disease-related isoform (PrP(Sc), where Sc is scrapie), the accumulation of which is associated with synapse degeneration and ultimately neuronal death. The formation of PrP(Sc) is dependent upon the presence of PrP(C) in specific, cholesterol-sensitive membrane microdomains, commonly called lipid rafts. PrP(C) is targeted to these lipid rafts because it is attached to membranes via a glycosylphosphatidylinositol anchor. Here, we show that treatment of prion-infected neuronal cell lines (ScN2a, ScGT1, or SMB cells) with synthetic glycosylphosphatidylinositol analogues, glucosamine-phosphatidylinositol (glucosamine-PI) or glucosamine 2-O-methyl inositol octadecyl phosphate, reduced the PrP(Sc) content of these cells in a dose-dependent manner. In addition, ScGT1 cells treated with glucosamine-PI did not transmit infection following intracerebral injection to mice. Treatment with glucosamine-PI increased the cholesterol content of ScGT1 cell membranes and reduced activation of cytoplasmic phospholipase A(2) (PLA(2)), consistent with the hypothesis that the composition of cell membranes affects key PLA(2)-dependent signaling pathways involved in PrP(Sc) formation. The effect of glucosamine-PI on PrP(Sc) formation was also reversed by the addition of platelet-activating factor. Glucosamine-PI caused the displacement of PrP(C) from lipid rafts and reduced expression of PrP(C) at the cell surface, putative sites for PrP(Sc) formation. We propose that treatment with glucosamine-PI modifies local micro-environments that control PrP(C) expression and activation of PLA(2) and subsequently inhibits PrP(Sc) formation.
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Affiliation(s)
- Clive Bate
- Department of Pathology and Infectious Diseases, Royal Veterinary College, Hawkshead Lane, North Mymms, Herts AL9 7TA, United Kingdom.
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Lorenzen A, Samosh J, Vandewark K, Anborgh PH, Seah C, Magalhaes AC, Cregan SP, Ferguson SSG, Pasternak SH. Rapid and direct transport of cell surface APP to the lysosome defines a novel selective pathway. Mol Brain 2010; 3:11. [PMID: 20409323 PMCID: PMC2868040 DOI: 10.1186/1756-6606-3-11] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2010] [Accepted: 04/21/2010] [Indexed: 12/03/2022] Open
Abstract
Background A central feature of Alzheimer's disease is the cleavage of the amyloid precursor protein (APP) to form beta-amyloid peptide (Aβ) by the β-secretase and γ-secretase enzymes. Although this has been shown to occur after endocytosis of APP from the cell surface, the exact compartments of APP processing are not well defined. We have previously demonstrated that APP and γ-secretase proteins and activity are highly enriched in purified rat liver lysosomes. In order to examine the lysosomal distribution and trafficking of APP in cultured cells, we generated constructs containing APP fused to a C-terminal fluorescent protein tag and N-terminal HA-epitope tag. These were co-transfected with a panel of fluorescent-protein tagged compartment markers. Results Here we demonstrate using laser-scanning confocal microscopy that although APP is present throughout the endosomal/lysosomal system in transfected Cos7 and neuronal SN56 cell lines as well as in immunostained cultured mouse neurons, it is enriched in the lysosome. We also show that the Swedish and London mutations reduce the amount of APP in the lysosome. Surprisingly, in addition to its expected trafficking from the cell surface to the early and then late endosomes, we find that cell-surface labelled APP is transported rapidly and directly from the cell surface to lysosomes in both Cos7 and SN56 cells. This rapid transit to the lysosome is blocked by the presence of either the London or Swedish mutations. Conclusions These results demonstrate the presence of a novel, rapid and specific transport pathway from the cell surface to the lysosomes. This suggests that regulation of lysosomal traffic could regulate APP processing and that the lysosome could play a central role in the pathophysiology of Alzheimer's disease.
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Affiliation(s)
- Angela Lorenzen
- J, Allyn Taylor Centre for Cell Biology, Molecular Brain Research Group, Robarts Research Institute, Schulich School of Medicine, the University of Western Ontario, London, Ontario, N6A 5K8, Canada
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Bate C, Tayebi M, Diomede L, Salmona M, Williams A. Glimepiride reduces the expression of PrPc, prevents PrPSc formation and protects against prion mediated neurotoxicity in cell lines. PLoS One 2009; 4:e8221. [PMID: 20011040 PMCID: PMC2784943 DOI: 10.1371/journal.pone.0008221] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2009] [Accepted: 11/11/2009] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND A hallmark of the prion diseases is the conversion of the host-encoded cellular prion protein (PrP(C)) into a disease related, alternatively folded isoform (PrP(Sc)). The accumulation of PrP(Sc) within the brain is associated with synapse loss and ultimately neuronal death. Novel therapeutics are desperately required to treat neurodegenerative diseases including the prion diseases. PRINCIPAL FINDINGS Treatment with glimepiride, a sulphonylurea approved for the treatment of diabetes mellitus, induced the release of PrP(C) from the surface of prion-infected neuronal cells. The cell surface is a site where PrP(C) molecules may be converted to PrP(Sc) and glimepiride treatment reduced PrP(Sc) formation in three prion infected neuronal cell lines (ScN2a, SMB and ScGT1 cells). Glimepiride also protected cortical and hippocampal neurones against the toxic effects of the prion-derived peptide PrP82-146. Glimepiride treatment significantly reduce both the amount of PrP82-146 that bound to neurones and PrP82-146 induced activation of cytoplasmic phospholipase A(2) (cPLA(2)) and the production of prostaglandin E(2) that is associated with neuronal injury in prion diseases. Our results are consistent with reports that glimepiride activates an endogenous glycosylphosphatidylinositol (GPI)-phospholipase C which reduced PrP(C) expression at the surface of neuronal cells. The effects of glimepiride were reproduced by treatment of cells with phosphatidylinositol-phospholipase C (PI-PLC) and were reversed by co-incubation with p-chloromercuriphenylsulphonate, an inhibitor of endogenous GPI-PLC. CONCLUSIONS Collectively, these results indicate that glimepiride may be a novel treatment to reduce PrP(Sc) formation and neuronal damage in prion diseases.
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Affiliation(s)
- Clive Bate
- Department of Pathology and Infectious Diseases, Royal Veterinary College, North Mymms, United Kingdom.
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Kang YS, Zhao X, Lovaas J, Eisenberg E, Greene LE. Clathrin-independent internalization of normal cellular prion protein in neuroblastoma cells is associated with the Arf6 pathway. J Cell Sci 2009; 122:4062-9. [PMID: 19843586 DOI: 10.1242/jcs.046292] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
To understand the role of clathrin-mediated endocytosis in the internalization of normal cellular prion protein (PrP(c)) in neuronal cells, N2a cells were depleted of clathrin by RNA interference. PrP(c) internalization via the constitutive endocytic pathway in the absence of Cu(2+) and the stimulated pathway in the presence of Cu(2+) were measured in both control and clathrin-depleted cells. Depletion of clathrin had almost no effect on the internalization of PrP(c) either in the presence or absence of Cu(2+), in contrast to the marked reduction observed in transferrin uptake. By contrast, the internalization of PrP(c) was inhibited by the raft-disrupting drugs filipin and nystatin, and by the dominant-negative dynamin-1 mutant dynamin-1 K44A, both in the presence and absence of Cu(2+). The internalized PrP(c) was found to colocalize with cargo that traffic in the Arf6 pathway and in large vacuoles in cells expressing the Arf6 dominant-active mutant. These results show that PrP(c) is internalized in a clathrin-independent pathway that is associated with Arf6.
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Lakhan SE, Sabharanjak S, De A. Endocytosis of glycosylphosphatidylinositol-anchored proteins. J Biomed Sci 2009; 16:93. [PMID: 19832981 PMCID: PMC2764642 DOI: 10.1186/1423-0127-16-93] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2009] [Accepted: 10/15/2009] [Indexed: 12/12/2022] Open
Abstract
Glycosylphosphatidylinositol-anchored proteins (GPI-APs) represent an interesting amalgamation of the three basic kinds of cellular macromolecules viz. proteins, carbohydrates and lipids. An unusually hybrid moiety, the GPI-anchor is expressed in a diverse range of organisms from parasites to mammalian cells and serves to anchor a large number of functionally diverse proteins and has been the center of attention in scientific debate for some time now. Membrane organization of GPI-APs into laterally-organized cholesterol-sphingolipid ordered membrane domains or "rafts" and endocytosis of GPI-APs has been intensely debated. Inclusion into or exclusion from these membrane domains seems to be the critical factor in determining the endocytic mechanisms and intracellular destinations of GPI-APs. The intracellular signaling as well as endocytic trafficking of GPI-APs is critically dependent upon the cell surface organization of GPI-APs, and the associations with these lipid rafts play a vital role during these processes. The mechanism of endocytosis for GPI-APs may differ from other cellular endocytic pathways, such as those mediated by clathrin-coated pits (caveolae), and is necessary for unique biological functions. Numerous intracellular factors are involved in and regulate the endocytosis of GPI-APs, and these may be variably dependent on cell-type. The central focus of this article is to describe the significance of the endocytosis of GPI-APs on a multitude of biological processes, ranging from nutrient-uptake to more complex immune responses. Ultimately, a thorough elucidation of GPI-AP mediated signaling pathways and their regulatory elements will enhance our understanding of essential biological processes and benefit as components of disease intervention strategies.
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Affiliation(s)
- Shaheen E Lakhan
- Global Neuroscience Initiative Foundation, Los Angeles, CA, USA.
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Haigh CL, Lewis VA, Vella LJ, Masters CL, Hill AF, Lawson VA, Collins SJ. PrPC-related signal transduction is influenced by copper, membrane integrity and the alpha cleavage site. Cell Res 2009; 19:1062-78. [PMID: 19597535 DOI: 10.1038/cr.2009.86] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
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Marijanovic Z, Caputo A, Campana V, Zurzolo C. Identification of an intracellular site of prion conversion. PLoS Pathog 2009; 5:e1000426. [PMID: 19424437 PMCID: PMC2673690 DOI: 10.1371/journal.ppat.1000426] [Citation(s) in RCA: 140] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2008] [Accepted: 04/13/2009] [Indexed: 01/01/2023] Open
Abstract
Prion diseases are fatal, neurodegenerative disorders in humans and animals and are characterized by the accumulation of an abnormally folded isoform of the cellular prion protein (PrPC), denoted PrPSc, which represents the major component of infectious scrapie prions. Characterization of the mechanism of conversion of PrPC into PrPSc and identification of the intracellular site where it occurs are among the most important questions in prion biology. Despite numerous efforts, both of these questions remain unsolved. We have quantitatively analyzed the distribution of PrPC and PrPSc and measured PrPSc levels in different infected neuronal cell lines in which protein trafficking has been selectively impaired. Our data exclude roles for both early and late endosomes and identify the endosomal recycling compartment as the likely site of prion conversion. These findings represent a fundamental step towards understanding the cellular mechanism of prion conversion and will allow the development of new therapeutic approaches for prion diseases. The misfolded form (PrPSc or prion) of the naturally occuring prion protein (PrPC or cellular PrP) is responsible for neurodegenerative diseases such as Creutzfeldt-Jakob disease (CJD), bovine spongiform encephalopathy (BSE) (also known as ‘mad cow disease’) and a new variant of CJD (vCJD), which is thought to be caused by ingestion of cattle-derived foodstuffs contaminated with prions. These diseases are characterized by the accumulation of protein deposits in the central nervous system (CNS). However, unlike other neurodegenerative diseases, prion diseases are infectious and prions are able to propagate in a chain reaction by imposing their malconformed state onto the properly folded cellular proteins. Understanding where the conversion of PrPC into PrPSc occurs in cells has been an unsolved question until now. By analysing the intracellular localization of PrPC and PrPSc and measuring the levels of PrPSc produced in infected neuronal cell lines under conditions in which intracellular trafficking of the protein is impaired, we found that prion conversion occurs in the endosomal recycling compartment (ERC) where it transits after being internalized from the cell surface. This study will help to clarify the cellular mechanism of the disease and it opens the way to new therapeutic strategies aimed at the conversion compartment.
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Affiliation(s)
- Zrinka Marijanovic
- Institut Pasteur, Unité Trafic Membranaire et Pathogénèse, Paris, France
| | - Anna Caputo
- Institut Pasteur, Unité Trafic Membranaire et Pathogénèse, Paris, France
- Dipartimento di Biologia e Patologia Cellulare e Molecolare, Università degli Studi di Napoli ‘Federico II’, Naples, Italy
| | - Vincenza Campana
- Institut Pasteur, Unité Trafic Membranaire et Pathogénèse, Paris, France
| | - Chiara Zurzolo
- Institut Pasteur, Unité Trafic Membranaire et Pathogénèse, Paris, France
- Dipartimento di Biologia e Patologia Cellulare e Molecolare, Università degli Studi di Napoli ‘Federico II’, Naples, Italy
- * E-mail: or
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Flores-Langarica A, Sebti Y, Mitchell DA, Sim RB, MacPherson GG. Scrapie pathogenesis: the role of complement C1q in scrapie agent uptake by conventional dendritic cells. THE JOURNAL OF IMMUNOLOGY 2009; 182:1305-13. [PMID: 19155476 DOI: 10.4049/jimmunol.182.3.1305] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Mice lacking complement components show delayed development of prion disease following peripheral inoculation. The delay could relate to reduced scrapie prion protein (PrP(Sc)) accumulation on follicular dendritic cells (DCs). However conventional DCs (cDCs) play a crucial role in the early pathogenesis of prion diseases and complement deficiency could result in decreased PrP(Sc) uptake by cDCs in the periphery. To explore this possibility, we cultured murine splenic or gut-associated lymph node cDCs with scrapie-infected whole brain homogenate in the presence or absence of complement. Uptake decreased significantly if the serum in the cultures was heat-inactivated. Because heat inactivation primarily denatures C1q, we used serum from C1q(-/-) mice and showed that PrP(Sc) uptake was markedly decreased. PrP(Sc) internalization was saturable and temperature-dependent, suggesting receptor-mediated uptake. Furthermore, uptake characteristics differed from fluid-phase endocytosis. Immunofluorescence showed colocalization of C1q and PrP(Sc), suggesting interaction between these molecules. We evaluated the expression of several complement receptors on cDCs and confirmed that cDCs that take up PrP(Sc) express one of the C1q receptors, calreticulin. Our results show that C1q participates in PrP(Sc) uptake by cDCs, revealing a critical role for cDCs in initial prion capture, an event that takes place before the PrP(Sc) accumulation within the follicular DC network.
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Affiliation(s)
- Adriana Flores-Langarica
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, OX1 3RE Oxford, UK
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50
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Lechauve C, Rezaei H, Celier C, Kiger L, Corral-Debrinski M, Noinville S, Chauvierre C, Hamdane D, Pato C, Marden MC. Neuroglobin and prion cellular localization: investigation of a potential interaction. J Mol Biol 2009; 388:968-77. [PMID: 19327369 DOI: 10.1016/j.jmb.2009.03.047] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2008] [Revised: 02/18/2009] [Accepted: 03/18/2009] [Indexed: 11/25/2022]
Abstract
Neuroglobin (Ngb) and the cellular prion protein (PrP(c)), proteins of unknown function in the nervous system, are known to be expressed in the retina and have been observed in different rat retinal cells. The retina is the site of the highest concentration for Ngb, a heme protein of similar size and conformation to myoglobin. In this study, we demonstrated by immunohistochemical analysis of retinal colocalization of Ngb and PrP(c) in the ganglion cell layer. Considering for these two a common protective role in relation to oxidative stress and a possible transient contact during migration of PrP(c) through the eye or upon neuronal degradation, we undertook in vitro studies of the interaction of the purified proteins. Mixing these two proteins leads to rapid aggregation, even at submicromolar concentrations. As observed with the use of dynamic light scattering, particles comprising both proteins evolve to hundreds of nanometers within several seconds, a first report showing that PrP(c) is able to form aggregates without major structural changes. The main effect would then appear to be a protein-protein interaction specific to the surface charge of the Ngb protein with PrP(c) N-terminal sequence. A dominant parameter is the solvent ionic force, which can significantly modify the final state of aggregation. PrP(c), normally anchored to the cell membrane, is toxic in the cytoplasm, where Ngb is present; this could suggest an Ngb function of scavenging proteins capable of forming deleterious aggregates considering a charge complementarity in the complex.
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Affiliation(s)
- Christophe Lechauve
- INSERM U779, Universités Paris VI et XI, Hopital de Bicêtre, Le Kremlin-Bicêtre, France
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