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Stanley B Prusiner - One of the best experts on this subject based on the ideXlab platform.
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Prion Protein mediator of toxicity in multiple Proteinopathies
Nature Reviews Neurology, 2020Co-Authors: Jacob I Ayers, Stanley B PrusinerAbstract:A new study shows that interactions of the cellular Prion Protein with amyloid-β, tau and α-synuclein oligomers are important in mediating the toxicity of these Proteins in Alzheimer disease and Parkinson disease. The findings suggest a shared pathway that could be a therapeutic target common to multiple neurodegenerative diseases.
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guinea pig Prion Protein supports rapid propagation of bovine spongiform encephalopathy and variant creutzfeldt jakob disease Prions
Journal of Virology, 2016Co-Authors: Joel C Watts, Kurt Giles, Daniel J Saltzberg, Brittany N Dugger, Smita S Patel, Abby Oehler, Sumita Bhardwaj, Andrej Sali, Stanley B PrusinerAbstract:Author(s): Watts, Joel C; Giles, Kurt; Saltzberg, Daniel J; Dugger, Brittany N; Patel, Smita; Oehler, Abby; Bhardwaj, Sumita; Sali, Andrej; Prusiner, Stanley B | Abstract: The biochemical and neuropathological properties of bovine spongiform encephalopathy (BSE) and variant Creutzfeldt-Jakob disease (vCJD) Prions are faithfully maintained upon transmission to guinea pigs. However, primary and secondary transmissions of BSE and vCJD in guinea pigs result in long incubation periods of ∼450 and ∼350 days, respectively. To determine if the incubation periods of BSE and vCJD Prions could be shortened, we generated transgenic (Tg) mice expressing guinea pig Prion Protein (GPPrP). Inoculation of Tg(GPPrP) mice with BSE and vCJD Prions resulted in mean incubation periods of 210 and 199 days, respectively, which shortened to 137 and 122 days upon serial transmission. In contrast, three different isolates of sporadic CJD Prions failed to transmit disease to Tg(GPPrP) mice. Many of the strain-specified biochemical and neuropathological properties of BSE and vCJD Prions, including the presence of type 2 protease-resistant PrPSc, were preserved upon propagation in Tg(GPPrP) mice. Structural modeling revealed that two residues near the N-terminal region of α-helix 1 in GPPrP might mediate its susceptibility to BSE and vCJD Prions. Our results demonstrate that expression of GPPrP in Tg mice supports the rapid propagation of BSE and vCJD Prions and suggest that Tg(GPPrP) mice may serve as a useful paradigm for bioassaying these Prion isolates. IMPORTANCE:Variant Creutzfeldt-Jakob disease (vCJD) and bovine spongiform encephalopathy (BSE) Prions are two of the Prion strains most relevant to human health. However, propagating these strains in mice expressing human or bovine Prion Protein has been difficult because of prolonged incubation periods or inefficient transmission. Here, we show that transgenic mice expressing guinea pig Prion Protein are fully susceptible to vCJD and BSE Prions but not to sporadic CJD Prions. Our results suggest that the guinea pig Prion Protein is a better, more rapid substrate than either bovine or human Prion Protein for propagating BSE and vCJD Prions.
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structural studies of the scrapie Prion Protein by electron crystallography
Proceedings of the National Academy of Sciences of the United States of America, 2002Co-Authors: Holger Wille, Melissa D Michelitsch, Vincent Guenebaut, Ana Serban, Surachai Supattapone, Fred E. Cohen, David A Agard, Stanley B PrusinerAbstract:Because the insolubility of the scrapie Prion Protein (PrPSc) has frustrated structural studies by x-ray crystallography or NMR spectroscopy, we used electron crystallography to characterize the structure of two infectious variants of the Prion Protein. Isomorphous two-dimensional crystals of the N-terminally truncated PrPSc (PrP 27-30) and a miniPrion (PrPSc106) were identified by negative stain electron microscopy. Image processing allowed the extraction of limited structural information to 7 Å resolution. By comparing projection maps of PrP 27-30 and PrPSc106, we visualized the 36-residue internal deletion of the miniPrion and localized the N-linked sugars. The dimensions of the monomer and the locations of the deleted segment and sugars were used as constraints in the construction of models for PrPSc. Only models featuring parallel β-helices as the key element could satisfy the constraints. These low-resolution projection maps and models have implications for understanding Prion propagation and the pathogenesis of neurodegeneration.
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structural studies of the scrapie Prion Protein by electron crystallography
Proceedings of the National Academy of Sciences of the United States of America, 2002Co-Authors: Holger Wille, Melissa D Michelitsch, Vincent Guenebaut, Ana Serban, Surachai Supattapone, David A Agard, Frederick Cohen, Stanley B PrusinerAbstract:Because the insolubility of the scrapie Prion Protein (PrP(Sc)) has frustrated structural studies by x-ray crystallography or NMR spectroscopy, we used electron crystallography to characterize the structure of two infectious variants of the Prion Protein. Isomorphous two-dimensional crystals of the N-terminally truncated PrP(Sc) (PrP 27-30) and a miniPrion (PrP(Sc)106) were identified by negative stain electron microscopy. Image processing allowed the extraction of limited structural information to 7 A resolution. By comparing projection maps of PrP 27-30 and PrP(Sc)106, we visualized the 36-residue internal deletion of the miniPrion and localized the N-linked sugars. The dimensions of the monomer and the locations of the deleted segment and sugars were used as constraints in the construction of models for PrP(Sc). Only models featuring parallel beta-helices as the key element could satisfy the constraints. These low-resolution projection maps and models have implications for understanding Prion propagation and the pathogenesis of neurodegeneration.
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folding of Prion Protein to its native α helical conformation is under kinetic control
Journal of Biological Chemistry, 2001Co-Authors: Ilia V Baskakov, Stanley B Prusiner, Giuseppe Legname, Fred E. CohenAbstract:Abstract The recombinant mouse Prion Protein (MoPrP) can be folded either to a monomeric α-helical or oligomeric β-sheet-rich isoform. By using circular dichroism spectroscopy and size-exclusion chromatography, we show that the β-rich isoform of MoPrP is thermodynamically more stable than the native α-helical isoform. The conformational transition from the α-helical to β-rich isoform is separated by a large energetic barrier that is associated with unfolding and with a higher order kinetic process related to oligomerization. Under partially denaturing acidic conditions, MoPrP avoids the kinetic trap posed by the α-helical isoform and folds directly to the thermodynamically more stable β-rich isoform. Our data demonstrate that the folding of the Prion Protein to its native α-helical monomeric conformation is under kinetic control.
Laura T Haas - One of the best experts on this subject based on the ideXlab platform.
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metabotropic glutamate receptor 5 couples cellular Prion Protein to intracellular signalling in alzheimer s disease
Brain, 2016Co-Authors: Laura T Haas, Santiago V Salazar, Mikhail A Kostylev, Adam C Kaufman, Ji Won Um, Stephen M. StrittmatterAbstract:Alzheimer’s disease-related phenotypes in mice can be rescued by blockade of either cellular Prion Protein or metabotropic glutamate receptor 5. We sought genetic and biochemical evidence that these Proteins function cooperatively as an obligate complex in the brain. We show that cellular Prion Protein associates via transmembrane metabotropic glutamate receptor 5 with the intracellular Protein mediators Homer1b/c, calcium/calmodulin-dependent Protein kinase II, and the Alzheimer’s disease risk gene product Protein tyrosine kinase 2 beta. Coupling of cellular Prion Protein to these intracellular Proteins is modified by soluble amyloid-β oligomers, by mouse brain Alzheimer’s disease transgenes or by human Alzheimer’s disease pathology. Amyloid-β oligomer-triggered phosphorylation of intracellular Protein mediators and impairment of synaptic plasticity in vitro requires Prnp–Grm5 genetic interaction, being absent in transheterozygous loss-of-function, but present in either single heterozygote. Importantly, genetic coupling between Prnp and Grm5 is also responsible for signalling, for survival and for synapse loss in Alzheimer’s disease transgenic model mice. Thus, the interaction between metabotropic glutamate receptor 5 and cellular Prion Protein has a central role in Alzheimer’s disease pathogenesis, and the complex is a potential target for disease-modifying intervention. * Abbreviations : APP/PS1+ : amyloid precursor Protein/presenilin 1 CamKII : calcium/calmodulin-dependent Protein kinase II eEF2 : eukaryotic elongation factor 2 EPSP : excitatory postsynaptic potential HEK-293T : human embryonic kidney-293T Homer1a/b/c : homer scaffolding Protein 1 splice variants a/b/c LTP : long-term potentiation mGluR5 : metabotropic glutamate receptor 5 PrPC : cellular Prion Protein Pyk2 : proline rich tyrosine kinase 2 RIPA : radioimmunoprecipitation assay
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metabotropic glutamate receptor 5 couples cellular Prion Protein to intracellular signalling in alzheimer s disease
Brain, 2016Co-Authors: Laura T Haas, Santiago V Salazar, Mikhail A Kostylev, Adam C Kaufman, Stephen M. StrittmatterAbstract:Alzheimer's disease-related phenotypes in mice can be rescued by blockade of either cellular Prion Protein or metabotropic glutamate receptor 5. We sought genetic and biochemical evidence that these Proteins function cooperatively as an obligate complex in the brain. We show that cellular Prion Protein associates via transmembrane metabotropic glutamate receptor 5 with the intracellular Protein mediators Homer1b/c, calcium/calmodulin-dependent Protein kinase II, and the Alzheimer's disease risk gene product Protein tyrosine kinase 2 beta. Coupling of cellular Prion Protein to these intracellular Proteins is modified by soluble amyloid-β oligomers, by mouse brain Alzheimer's disease transgenes or by human Alzheimer's disease pathology. Amyloid-β oligomer-triggered phosphorylation of intracellular Protein mediators and impairment of synaptic plasticity in vitro requires Prnp-Grm5 genetic interaction, being absent in transheterozygous loss-of-function, but present in either single heterozygote. Importantly, genetic coupling between Prnp and Grm5 is also responsible for signalling, for survival and for synapse loss in Alzheimer's disease transgenic model mice. Thus, the interaction between metabotropic glutamate receptor 5 and cellular Prion Protein has a central role in Alzheimer's disease pathogenesis, and the complex is a potential target for disease-modifying intervention.
Stephen M. Strittmatter - One of the best experts on this subject based on the ideXlab platform.
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metabotropic glutamate receptor 5 couples cellular Prion Protein to intracellular signalling in alzheimer s disease
Brain, 2016Co-Authors: Laura T Haas, Santiago V Salazar, Mikhail A Kostylev, Adam C Kaufman, Ji Won Um, Stephen M. StrittmatterAbstract:Alzheimer’s disease-related phenotypes in mice can be rescued by blockade of either cellular Prion Protein or metabotropic glutamate receptor 5. We sought genetic and biochemical evidence that these Proteins function cooperatively as an obligate complex in the brain. We show that cellular Prion Protein associates via transmembrane metabotropic glutamate receptor 5 with the intracellular Protein mediators Homer1b/c, calcium/calmodulin-dependent Protein kinase II, and the Alzheimer’s disease risk gene product Protein tyrosine kinase 2 beta. Coupling of cellular Prion Protein to these intracellular Proteins is modified by soluble amyloid-β oligomers, by mouse brain Alzheimer’s disease transgenes or by human Alzheimer’s disease pathology. Amyloid-β oligomer-triggered phosphorylation of intracellular Protein mediators and impairment of synaptic plasticity in vitro requires Prnp–Grm5 genetic interaction, being absent in transheterozygous loss-of-function, but present in either single heterozygote. Importantly, genetic coupling between Prnp and Grm5 is also responsible for signalling, for survival and for synapse loss in Alzheimer’s disease transgenic model mice. Thus, the interaction between metabotropic glutamate receptor 5 and cellular Prion Protein has a central role in Alzheimer’s disease pathogenesis, and the complex is a potential target for disease-modifying intervention. * Abbreviations : APP/PS1+ : amyloid precursor Protein/presenilin 1 CamKII : calcium/calmodulin-dependent Protein kinase II eEF2 : eukaryotic elongation factor 2 EPSP : excitatory postsynaptic potential HEK-293T : human embryonic kidney-293T Homer1a/b/c : homer scaffolding Protein 1 splice variants a/b/c LTP : long-term potentiation mGluR5 : metabotropic glutamate receptor 5 PrPC : cellular Prion Protein Pyk2 : proline rich tyrosine kinase 2 RIPA : radioimmunoprecipitation assay
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metabotropic glutamate receptor 5 couples cellular Prion Protein to intracellular signalling in alzheimer s disease
Brain, 2016Co-Authors: Laura T Haas, Santiago V Salazar, Mikhail A Kostylev, Adam C Kaufman, Stephen M. StrittmatterAbstract:Alzheimer's disease-related phenotypes in mice can be rescued by blockade of either cellular Prion Protein or metabotropic glutamate receptor 5. We sought genetic and biochemical evidence that these Proteins function cooperatively as an obligate complex in the brain. We show that cellular Prion Protein associates via transmembrane metabotropic glutamate receptor 5 with the intracellular Protein mediators Homer1b/c, calcium/calmodulin-dependent Protein kinase II, and the Alzheimer's disease risk gene product Protein tyrosine kinase 2 beta. Coupling of cellular Prion Protein to these intracellular Proteins is modified by soluble amyloid-β oligomers, by mouse brain Alzheimer's disease transgenes or by human Alzheimer's disease pathology. Amyloid-β oligomer-triggered phosphorylation of intracellular Protein mediators and impairment of synaptic plasticity in vitro requires Prnp-Grm5 genetic interaction, being absent in transheterozygous loss-of-function, but present in either single heterozygote. Importantly, genetic coupling between Prnp and Grm5 is also responsible for signalling, for survival and for synapse loss in Alzheimer's disease transgenic model mice. Thus, the interaction between metabotropic glutamate receptor 5 and cellular Prion Protein has a central role in Alzheimer's disease pathogenesis, and the complex is a potential target for disease-modifying intervention.
Witold K Surewicz - One of the best experts on this subject based on the ideXlab platform.
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conformational stability of mammalian Prion Protein amyloid fibrils is dictated by a packing polymorphism within the core region
Journal of Biological Chemistry, 2014Co-Authors: Nathan J Cobb, Marcin I Apostol, Shugui Chen, Vytautas Smirnovas, Witold K SurewiczAbstract:Mammalian Prion strains are believed to arise from the propagation of distinct conformations of the misfolded Prion Protein PrPSc. One key operational parameter used to define differences between strains has been conformational stability of PrPSc as defined by resistance to thermal and/or chemical denaturation. However, the structural basis of these stability differences is unknown. To bridge this gap, we have generated two strains of recombinant human Prion Protein amyloid fibrils that show dramatic differences in conformational stability and have characterized them by a number of biophysical methods. Backbone amide hydrogen/deuterium exchange experiments revealed that, in sharp contrast to previously studied strains of infectious amyloid formed from the yeast Prion Protein Sup35, differences in β-sheet core size do not underlie differences in conformational stability between strains of mammalian Prion Protein amyloid. Instead, these stability differences appear to be dictated by distinct packing arrangements (i.e. steric zipper interfaces) within the amyloid core, as indicated by distinct x-ray fiber diffraction patterns and large strain-dependent differences in hydrogen/deuterium exchange kinetics for histidine side chains within the core region. Although this study was limited to synthetic Prion Protein amyloid fibrils, a similar structural basis for strain-dependent conformational stability may apply to brain-derived PrPSc, especially because large strain-specific differences in PrPSc stability are often observed despite a similar size of the PrPSc core region.
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soluble Prion Protein inhibits amyloid β aβ fibrillization and toxicity
Journal of Biological Chemistry, 2012Co-Authors: Krzysztof Nieznanski, Shugui Chen, Jinkyu Choi, Krystyna Surewicz, Witold K SurewiczAbstract:Abstract Pathogenesis of Alzheimer disease (AD) appears to be strongly linked to the aggregation of Aβ peptide and, especially, formation of soluble Aβ1-42 oligomers. It was recently demonstrated that the cellular Prion Protein, PrPC, binds with high affinity to these oligomers, acting as a putative receptor that mediates at least some of their neurotoxic effects. Here we show that the soluble (i.e., glycophoshatidylinositol anchor-free) Prion Protein and its N-terminal fragment have a strong effect on the aggregation pathway of Aβ1-42, inhibiting its assembly into amyloid fibrils. Furthermore, the Prion Protein prevents formation of spherical oligomers that normally occur during Aβ fibrillogenesis, acting as a potent inhibitor of Aβ1-42 toxicity as assessed in experiments with neuronal cell culture. These findings may provide a molecular level foundation to explain the reported protective action of the physiologically released N-terminal N1 fragment of PrPC against Aβ neurotoxicity. They also suggest a novel approach to pharmacological intervention in AD.
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the role of glycophosphatidylinositol anchor in the amplification of the scrapie isoform of Prion Protein in vitro
FEBS Letters, 2009Co-Authors: Jae Il Kim, Krystyna Surewicz, Pierluigi Gambetti, Witold K SurewiczAbstract:Transmissible spongiform encephalopathies are associated with an autocatalytic conversion of normal Prion Protein, PrPC, to a protease-resistant form, PrPres. This autocatalytic reaction can be reproduced in vitro using a procedure called Protein misfolding cyclic amplification (PMCA). Here we show that, unlike brain-derived PrPC, bacterially-expressed recombinant Prion Protein (rPrP) is a poor substrate for PrPres amplification in a standard PMCA reaction. The differences between PrPC and rPrP appear to be due to the lack of the glycophosphatidylinositol anchor in the recombinant Protein. These findings shed a new light on Prion Protein conversion process and have important implications for the efforts to generate synthetic Prions for structural and biophysical studies.
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the effect of disease associated mutations on the folding pathway of human Prion Protein
Journal of Biological Chemistry, 2004Co-Authors: Adrian C Apetri, Krystyna Surewicz, Witold K SurewiczAbstract:Abstract Propagation of transmissible spongiform encephalopathies is believed to involve the conversion of cellular Prion Protein, PrPC, into a misfolded oligomeric form, PrPSc. An important step toward understanding the mechanism of this conversion is to elucidate the folding pathway(s) of the Prion Protein. We reported recently (Apetri, A. C., and Surewicz, W. K. (2002) J. Biol. Chem. 277, 44589-44592) that the folding of wild-type Prion Protein can best be described by a three-state sequential model involving a partially folded intermediate. Here we have performed kinetic stopped-flow studies for a number of recombinant Prion Protein variants carrying mutations associated with familial forms of Prion disease. Analysis of kinetic data clearly demonstrates the presence of partially structured intermediates on the refolding pathway of each PrP variant studied. In each case, the partially folded state is at least one order of magnitude more populated than the fully unfolded state. The present study also reveals that, for the majority of PrP variants tested, mutations linked to familial Prion diseases result in a pronounced increase in the thermodynamic stability, and thus the population, of the folding intermediate. These data strongly suggest that partially structured intermediates of PrP may play a crucial role in Prion Protein conversion, serving as direct precursors of the pathogenic PrPSc isoform.
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crystal structure of the human Prion Protein reveals a mechanism for oligomerization
Nature Structural & Molecular Biology, 2002Co-Authors: Witold K Surewicz, Karen Knaus, Manuel Morillas, Wieslaw Swietnicki, Michael H Malone, Vivien C YeeAbstract:The pathogenesis of transmissible encephalopathies is associated with the conversion of the cellular Prion Protein, PrP(C), into a conformationally altered oligomeric form, PrP(Sc). Here we report the crystal structure of the human Prion Protein in dimer form at 2 A resolution. The dimer results from the three-dimensional swapping of the C-terminal helix 3 and rearrangement of the disulfide bond. An interchain two-stranded antiparallel beta-sheet is formed at the dimer interface by residues that are located in helix 2 in the monomeric NMR structures. Familial Prion disease mutations map to the regions directly involved in helix swapping. This crystal structure suggests that oligomerization through 3D domain-swapping may constitute an important step on the pathway of the PrP(C) --> PrP(Sc) conversion.
Byron Caughey - One of the best experts on this subject based on the ideXlab platform.
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distribution of misfolded Prion Protein seeding activity alone does not predict regions of neurodegeneration
PLOS Biology, 2016Co-Authors: James Alibhai, Byron Caughey, Pedro Piccardo, Richard A Blanco, Marcelo A Barria, Hugh V Perry, Tom C Freeman, Jean MansonAbstract:Protein misfolding is common across many neurodegenerative diseases, with misfolded Proteins acting as seeds for "Prion-like" conversion of normally folded Protein to abnormal conformations. A central hypothesis is that misfolded Protein accumulation, spread, and distribution are restricted to specific neuronal populations of the central nervous system and thus predict regions of neurodegeneration. We examined this hypothesis using a highly sensitive assay system for detection of misfolded Protein seeds in a murine model of Prion disease. Misfolded Prion Protein (PrP) seeds were observed widespread throughout the brain, accumulating in all brain regions examined irrespective of neurodegeneration. Importantly, neither time of exposure nor amount of misfolded Protein seeds present determined regions of neurodegeneration. We further demonstrate two distinct microglia responses in Prion-infected brains: a novel homeostatic response in all regions and an innate immune response restricted to sites of neurodegeneration. Therefore, accumulation of misfolded Prion Protein alone does not define targeting of neurodegeneration, which instead results only when misfolded Prion Protein accompanies a specific innate immune response.
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mammalian Prions generated from bacterially expressed Prion Protein in the absence of any mammalian cofactors
Journal of Biological Chemistry, 2010Co-Authors: Ignazio Cali, Krystyna Surewicz, Pierluigi Gambetti, Ryuichiro Atarashi, Qingzhong Kong, Gregory J Raymond, Brent Race, Liuting Qing, Byron CaugheyAbstract:Transmissible spongiform encephalopathies (TSEs) are a group of neurodegenerative diseases that are associated with the conformational conversion of a normal Prion Protein, PrPC, to a misfolded aggregated form, PrPSc. The Protein-only hypothesis asserts that PrPSc itself represents the infectious TSE agent. Although this model is supported by rapidly growing experimental data, unequivocal proof has been elusive. The Protein misfolding cyclic amplification reactions have been recently shown to propagate Prions using brain-derived or recombinant Prion Protein, but only in the presence of additional cofactors such as nucleic acids and lipids. Here, using a Protein misfolding cyclic amplification variation, we show that Prions causing transmissible spongiform encephalopathy in wild-type hamsters can be generated solely from highly purified, bacterially expressed recombinant hamster Prion Protein without any mammalian or synthetic cofactors (other than buffer salts and detergent). These findings provide strong support for the Protein-only hypothesis of TSE diseases, as well as argue that cofactors such as nucleic acids, other polyanions, or lipids are non-obligatory for Prion Protein conversion to the infectious form.
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ultrasensitive detection of scrapie Prion Protein using seeded conversion of recombinant Prion Protein
Nature Methods, 2007Co-Authors: Ryuichiro Atarashi, Roger A Moore, Andrew G Hughson, David W Dorward, Henry A Onwubiko, Suzette A Priola, Byron CaugheyAbstract:Ultrasensitive detection of scrapie Prion Protein using seeded conversion of recombinant Prion Protein
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ultrasensitive detection of scrapie Prion Protein using seeded conversion of recombinant Prion Protein
Nature Methods, 2007Co-Authors: Ryuichiro Atarashi, Valerie L Sim, Roger A Moore, Andrew G Hughson, David W Dorward, Henry A Onwubiko, Suzette A Priola, Byron CaugheyAbstract:The scrapie Prion Protein isoform, PrPSc, is a Prion-associated marker that seeds the conformational conversion and polymerization of normal protease-sensitive Prion Protein (PrP-sen). This seeding activity allows ultrasensitive detection of PrPSc using cyclical sonicated amplification (PMCA) reactions and brain homogenate as a source of PrP-sen. Here we describe a much faster seeded polymerization method (rPrP-PMCA) which detects ≥50 ag of hamster PrPSc (≈0.003 lethal dose) within 2–3 d. This technique uses recombinant hamster PrP-sen, which, unlike brain-derived PrP-sen, can be easily concentrated, mutated and synthetically tagged. We generated protease-resistant recombinant PrP fibrils that differed from spontaneously initiated fibrils in their proteolytic susceptibility and by their infrared spectra. This assay could discriminate between scrapie-infected and uninfected hamsters using 2-μl aliquots of cerebral spinal fluid. This method should facilitate the development of rapid, ultrasensitive Prion assays and diagnostic tests, in addition to aiding fundamental studies of structure and mechanism of PrPSc formation.
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Lysosomotropic Agents and Cysteine Protease Inhibitors Inhibit Scrapie-Associated Prion Protein Accumulation
Journal of Virology, 2000Co-Authors: Katsumi Doh-ura, Toru Iwaki, Byron CaugheyAbstract:We report that lysosomotropic agents and cysteine protease inhibitors inhibited protease-resistant Prion Protein accumulation in scrapie-infected neuroblastoma cells. The inhibition occurred without either apparent effects on normal Prion Protein biosynthesis or turnover or direct interactions with Prion Protein molecules. The findings introduce two new classes of inhibitors of the formation of protease-resistant Prion Protein.