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Prion Propagation is Dependent on Key Amino Acids in Charge Cluster 2 within the Prion Protein. J Mol Biol 2023; 435:167925. [PMID: 36535427 DOI: 10.1016/j.jmb.2022.167925] [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: 08/16/2022] [Revised: 12/08/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022]
Abstract
To dissect the N-terminal residues within the cellular prion protein (PrPC) that are critical for efficient prion propagation, we generated a library of point, double, or triple alanine replacements within residues 23-111 of PrP, stably expressed them in cells silenced for endogenous mouse PrPC and challenged the reconstituted cells with four common but biologically diverse mouse prion strains. Amino acids (aa) 105-111 of Charge Cluster 2 (CC2), which is disordered in PrPC, were found to be required for propagation of all four prion strains; other residues had no effect or exhibited strain-specific effects. Replacements in CC2, including aa105-111, dominantly inhibited prion propagation in the presence of endogenous wild type PrPC whilst other changes were not inhibitory. Single alanine replacements within aa105-111 identified leucine 108 and valine 111 or the cluster of lysine 105, threonine 106 and asparagine 107 as critical for prion propagation. These residues mediate specific ordering of unstructured CC2 into β-sheets in the infectious prion fibrils from Rocky Mountain Laboratory (RML) and ME7 mouse prion strains.
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Pasiana AD, Miyata H, Chida J, Hara H, Imamura M, Atarashi R, Sakaguchi S. Central Residues in Prion Protein PrP C Are Crucial for Its Conversion into the Pathogenic Isoform. J Biol Chem 2022; 298:102381. [PMID: 35973512 PMCID: PMC9478402 DOI: 10.1016/j.jbc.2022.102381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 08/08/2022] [Accepted: 08/10/2022] [Indexed: 11/05/2022] Open
Abstract
Conformational conversion of the cellular prion protein, PrPC, into the amyloidogenic isoform, PrPSc, is a key pathogenic event in prion diseases. However, the conversion mechanism remains to be elucidated. Here, we generated Tg(PrPΔ91-106)-8545/Prnp0/0 mice, which overexpress mouse PrP lacking residues 91-106. We showed that none of the mice became sick after intracerebral inoculation with RML, 22L, and FK-1 prion strains nor accumulated PrPScΔ91-106 in their brains except for a small amount of PrPScΔ91-106 detected in one 22L-inoculated mouse. However, they developed disease around 85 days after inoculation with bovine spongiform encephalopathy (BSE) prions with PrPScΔ91-106 in their brains. These results suggest that residues 91-106 are important for PrPC conversion into PrPSc in infection with RML, 22L, and FK-1 prions but not BSE prions. We then narrowed down the residues 91-106 by transducing various PrP deletional mutants into RML- and 22L-infected cells and identified that PrP mutants lacking residues 97-99 failed to convert into PrPSc in these cells. Our in vitro conversion assay also showed that RML, 22L, and FK-1 prions did not convert PrPΔ97-99 into PrPScΔ97-99, but BSE prions did. We further found that PrP mutants with proline residues at positions 97 to 99 or charged residues at positions 97 and 99 completely or almost completely lost their converting activity into PrPSc in RML- and 22L-infected cells. These results suggest that the structurally flexible and noncharged residues 97-99 could be important for PrPC conversion into PrPSc following infection with RML, 22L, and FK-1 prions but not BSE prions.
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Affiliation(s)
- Agriani Dini Pasiana
- Division of Molecular Neurobiology, The Institute for Enzyme Research (KOSOKEN), Tokushima University, 3-18-15 Kuramoto, Tokushima 770-8503, Japan
| | - Hironori Miyata
- Animal Research Center, School of Medicine, University of Occupational and Environmental Health, Yahatanishi, Kitakyushu, Japan
| | - Junji Chida
- Division of Molecular Neurobiology, The Institute for Enzyme Research (KOSOKEN), Tokushima University, 3-18-15 Kuramoto, Tokushima 770-8503, Japan
| | - Hideyuki Hara
- Division of Molecular Neurobiology, The Institute for Enzyme Research (KOSOKEN), Tokushima University, 3-18-15 Kuramoto, Tokushima 770-8503, Japan
| | - Morikazu Imamura
- Division of Microbiology, Department of Infectious Diseases, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki 889-1692, Japan
| | - Ryuichiro Atarashi
- Division of Microbiology, Department of Infectious Diseases, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki 889-1692, Japan
| | - Suehiro Sakaguchi
- Division of Molecular Neurobiology, The Institute for Enzyme Research (KOSOKEN), Tokushima University, 3-18-15 Kuramoto, Tokushima 770-8503, Japan.
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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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Uchiyama K, Miyata H, Yamaguchi Y, Imamura M, Okazaki M, Pasiana AD, Chida J, Hara H, Atarashi R, Watanabe H, Kondoh G, Sakaguchi S. Strain-Dependent Prion Infection in Mice Expressing Prion Protein with Deletion of Central Residues 91-106. Int J Mol Sci 2020; 21:ijms21197260. [PMID: 33019549 PMCID: PMC7582732 DOI: 10.3390/ijms21197260] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 09/23/2020] [Accepted: 09/24/2020] [Indexed: 12/18/2022] Open
Abstract
Conformational conversion of the cellular prion protein, PrPC, into the abnormally folded isoform, PrPSc, is a key pathogenic event in prion diseases. However, the exact conversion mechanism remains largely unknown. Transgenic mice expressing PrP with a deletion of the central residues 91–106 were generated in the absence of endogenous PrPC, designated Tg(PrP∆91–106)/Prnp0/0 mice and intracerebrally inoculated with various prions. Tg(PrP∆91–106)/Prnp0/0 mice were resistant to RML, 22L and FK-1 prions, neither producing PrPSc∆91–106 or prions in the brain nor developing disease after inoculation. However, they remained marginally susceptible to bovine spongiform encephalopathy (BSE) prions, developing disease after elongated incubation times and accumulating PrPSc∆91–106 and prions in the brain after inoculation with BSE prions. Recombinant PrP∆91-104 converted into PrPSc∆91–104 after incubation with BSE-PrPSc-prions but not with RML- and 22L–PrPSc-prions, in a protein misfolding cyclic amplification assay. However, digitonin and heparin stimulated the conversion of PrP∆91–104 into PrPSc∆91–104 even after incubation with RML- and 22L-PrPSc-prions. These results suggest that residues 91–106 or 91–104 of PrPC are crucially involved in prion pathogenesis in a strain-dependent manner and may play a similar role to digitonin and heparin in the conversion of PrPC into PrPSc.
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Affiliation(s)
- Keiji Uchiyama
- Division of Molecular Neurobiology, The Institute for Enzyme Research (KOSOKEN), Tokushima University, 3-18-15 Kuramoto, Tokushima 770-8503, Japan; (K.U.); (Y.Y.); (M.O.); (A.D.P.); (J.C.); (H.H.)
| | - Hironori Miyata
- Animal Research Center, School of Medicine, University of Occupational and Environmental Health, Yahatanishi, Kitakyushu 807-8555, Japan;
| | - Yoshitaka Yamaguchi
- Division of Molecular Neurobiology, The Institute for Enzyme Research (KOSOKEN), Tokushima University, 3-18-15 Kuramoto, Tokushima 770-8503, Japan; (K.U.); (Y.Y.); (M.O.); (A.D.P.); (J.C.); (H.H.)
| | - Morikazu Imamura
- Division of Microbiology, Department of Infectious Diseases, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki 889-1692, Japan; (M.I.); (R.A.)
| | - Mariya Okazaki
- Division of Molecular Neurobiology, The Institute for Enzyme Research (KOSOKEN), Tokushima University, 3-18-15 Kuramoto, Tokushima 770-8503, Japan; (K.U.); (Y.Y.); (M.O.); (A.D.P.); (J.C.); (H.H.)
- Student Laboratory, Tokushima University, Faculty of Medicine, 3-18-15 Kuramoto, Tokushima 770-8503, Japan
| | - Agriani Dini Pasiana
- Division of Molecular Neurobiology, The Institute for Enzyme Research (KOSOKEN), Tokushima University, 3-18-15 Kuramoto, Tokushima 770-8503, Japan; (K.U.); (Y.Y.); (M.O.); (A.D.P.); (J.C.); (H.H.)
| | - Junji Chida
- Division of Molecular Neurobiology, The Institute for Enzyme Research (KOSOKEN), Tokushima University, 3-18-15 Kuramoto, Tokushima 770-8503, Japan; (K.U.); (Y.Y.); (M.O.); (A.D.P.); (J.C.); (H.H.)
| | - Hideyuki Hara
- Division of Molecular Neurobiology, The Institute for Enzyme Research (KOSOKEN), Tokushima University, 3-18-15 Kuramoto, Tokushima 770-8503, Japan; (K.U.); (Y.Y.); (M.O.); (A.D.P.); (J.C.); (H.H.)
| | - Ryuichiro Atarashi
- Division of Microbiology, Department of Infectious Diseases, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki 889-1692, Japan; (M.I.); (R.A.)
| | - Hitomi Watanabe
- Laboratory of Integrative Biological Science, Institute for Frontier Life and Medical Sciences, Kyoto University, Yoshida-Konoe-cho, Sakyo-ku, Kyoto 606-8501, Japan; (H.W.); (G.K.)
| | - Gen Kondoh
- Laboratory of Integrative Biological Science, Institute for Frontier Life and Medical Sciences, Kyoto University, Yoshida-Konoe-cho, Sakyo-ku, Kyoto 606-8501, Japan; (H.W.); (G.K.)
| | - Suehiro Sakaguchi
- Division of Molecular Neurobiology, The Institute for Enzyme Research (KOSOKEN), Tokushima University, 3-18-15 Kuramoto, Tokushima 770-8503, Japan; (K.U.); (Y.Y.); (M.O.); (A.D.P.); (J.C.); (H.H.)
- Correspondence:
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Hara H, Sakaguchi S. N-Terminal Regions of Prion Protein: Functions and Roles in Prion Diseases. Int J Mol Sci 2020; 21:ijms21176233. [PMID: 32872280 PMCID: PMC7504422 DOI: 10.3390/ijms21176233] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Revised: 08/25/2020] [Accepted: 08/27/2020] [Indexed: 01/30/2023] Open
Abstract
The normal cellular isoform of prion protein, designated PrPC, is constitutively converted to the abnormally folded, amyloidogenic isoform, PrPSc, in prion diseases, which include Creutzfeldt-Jakob disease in humans and scrapie and bovine spongiform encephalopathy in animals. PrPC is a membrane glycoprotein consisting of the non-structural N-terminal domain and the globular C-terminal domain. During conversion of PrPC to PrPSc, its 2/3 C-terminal region undergoes marked structural changes, forming a protease-resistant structure. In contrast, the N-terminal region remains protease-sensitive in PrPSc. Reverse genetic studies using reconstituted PrPC-knockout mice with various mutant PrP molecules have revealed that the N-terminal domain has an important role in the normal function of PrPC and the conversion of PrPC to PrPSc. The N-terminal domain includes various characteristic regions, such as the positively charged residue-rich polybasic region, the octapeptide repeat (OR) region consisting of five repeats of an octapeptide sequence, and the post-OR region with another positively charged residue-rich polybasic region followed by a stretch of hydrophobic residues. We discuss the normal functions of PrPC, the conversion of PrPC to PrPSc, and the neurotoxicity of PrPSc by focusing on the roles of the N-terminal regions in these topics.
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The N-Terminal Polybasic Region of Prion Protein Is Crucial in Prion Pathogenesis Independently of the Octapeptide Repeat Region. Mol Neurobiol 2019; 57:1203-1216. [DOI: 10.1007/s12035-019-01804-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 09/26/2019] [Indexed: 10/25/2022]
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Prion Protein Devoid of the Octapeptide Repeat Region Delays Bovine Spongiform Encephalopathy Pathogenesis in Mice. J Virol 2017; 92:JVI.01368-17. [PMID: 29046443 DOI: 10.1128/jvi.01368-17] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 10/05/2017] [Indexed: 12/26/2022] Open
Abstract
Conformational conversion of the cellular isoform of prion protein, PrPC, into the abnormally folded, amyloidogenic isoform, PrPSc, is a key pathogenic event in prion diseases, including Creutzfeldt-Jakob disease in humans and scrapie and bovine spongiform encephalopathy (BSE) in animals. We previously reported that the octapeptide repeat (OR) region could be dispensable for converting PrPC into PrPSc after infection with RML prions. We demonstrated that mice transgenically expressing mouse PrP with deletion of the OR region on the PrP knockout background, designated Tg(PrPΔOR)/Prnp0/0 mice, did not show reduced susceptibility to RML scrapie prions, with abundant accumulation of PrPScΔOR in their brains. We show here that Tg(PrPΔOR)/Prnp0/0 mice were highly resistant to BSE prions, developing the disease with markedly elongated incubation times after infection with BSE prions. The conversion of PrPΔOR into PrPScΔOR was markedly delayed in their brains. These results suggest that the OR region may have a crucial role in the conversion of PrPC into PrPSc after infection with BSE prions. However, Tg(PrPΔOR)/Prnp0/0 mice remained susceptible to RML and 22L scrapie prions, developing the disease without elongated incubation times after infection with RML and 22L prions. PrPScΔOR accumulated only slightly less in the brains of RML- or 22L-infected Tg(PrPΔOR)/Prnp0/0 mice than PrPSc in control wild-type mice. Taken together, these results indicate that the OR region of PrPC could play a differential role in the pathogenesis of BSE prions and RML or 22L scrapie prions.IMPORTANCE Structure-function relationship studies of PrPC conformational conversion into PrPSc are worthwhile to understand the mechanism of the conversion of PrPC into PrPSc We show here that, by inoculating Tg(PrPΔOR)/Prnp0/0 mice with the three different strains of RML, 22L, and BSE prions, the OR region could play a differential role in the conversion of PrPC into PrPSc after infection with RML or 22L scrapie prions and BSE prions. PrPΔOR was efficiently converted into PrPScΔOR after infection with RML and 22L prions. However, the conversion of PrPΔOR into PrPScΔOR was markedly delayed after infection with BSE prions. Further investigation into the role of the OR region in the conversion of PrPC into PrPSc after infection with BSE prions might be helpful for understanding the pathogenesis of BSE prions.
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Uchiyama K, Tomita M, Yano M, Chida J, Hara H, Das NR, Nykjaer A, Sakaguchi S. Prions amplify through degradation of the VPS10P sorting receptor sortilin. PLoS Pathog 2017; 13:e1006470. [PMID: 28665987 PMCID: PMC5509376 DOI: 10.1371/journal.ppat.1006470] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2017] [Revised: 07/13/2017] [Accepted: 06/14/2017] [Indexed: 01/09/2023] Open
Abstract
Prion diseases are a group of fatal neurodegenerative disorders caused by prions, which consist mainly of the abnormally folded isoform of prion protein, PrPSc. A pivotal pathogenic event in prion disease is progressive accumulation of prions, or PrPSc, in brains through constitutive conformational conversion of the cellular prion protein, PrPC, into PrPSc. However, the cellular mechanism by which PrPSc is progressively accumulated in prion-infected neurons remains unknown. Here, we show that PrPSc is progressively accumulated in prion-infected cells through degradation of the VPS10P sorting receptor sortilin. We first show that sortilin interacts with PrPC and PrPSc and sorts them to lysosomes for degradation. Consistently, sortilin-knockdown increased PrPSc accumulation in prion-infected cells. In contrast, overexpression of sortilin reduced PrPSc accumulation in prion-infected cells. These results indicate that sortilin negatively regulates PrPSc accumulation in prion-infected cells. The negative role of sortilin in PrPSc accumulation was further confirmed in sortilin-knockout mice infected with prions. The infected mice had accelerated prion disease with early accumulation of PrPSc in their brains. Interestingly, sortilin was reduced in prion-infected cells and mouse brains. Treatment of prion-infected cells with lysosomal inhibitors, but not proteasomal inhibitors, increased the levels of sortilin. Moreover, sortilin was reduced following PrPSc becoming detectable in cells after infection with prions. These results indicate that PrPSc accumulation stimulates sortilin degradation in lysosomes. Taken together, these results show that PrPSc accumulation of itself could impair the sortilin-mediated sorting of PrPC and PrPSc to lysosomes for degradation by stimulating lysosomal degradation of sortilin, eventually leading to progressive accumulation of PrPSc in prion-infected cells. Once prions consisting mainly of PrPSc infect hosts, they constitutively propagate in their brains. Progressive production of PrPSc through the constitutive conformational conversion of PrPC into PrPSc underlies prion propagation. However, the mechanism enabling progressive production of PrPSc in prion-infected cells remains unknown. We here found that the VPS10P sorting receptor sortilin is involved in degradation of PrPC and PrPSc in infected cells by binding to both molecules and subsequently trafficking them to the lysosomal protein degradation pathway. Interestingly, we also found that degradation of sortilin was stimulated in lysosomes in prion-infected cells possibly as a result of the sortilin-PrPC or -PrPSc complexes being trafficked to lysosomes. Our findings indicate that PrPSc itself impairs the sortilin-mediated degradation of PrPC and PrPSc by stimulating degradation of sortilin in lysosomes. This eventually results in progressive production of PrPSc in prion-infected cells by increasing the opportunity of PrPC to convert into PrPSc and by accumulating the already produced PrPSc. This mechanism was confirmed in sortilin-KO mice infected with prions. The mice had exacerbated prion disease with earlier accumulation of PrPSc in their brains.
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Affiliation(s)
- Keiji Uchiyama
- Division of Molecular Neurobiology, Institute for Enzyme Research (KOSOKEN), Tokushima University, Tokushima, Japan
- * E-mail: (SS); (KU)
| | - Mitsuru Tomita
- Division of Molecular Neurobiology, Institute for Enzyme Research (KOSOKEN), Tokushima University, Tokushima, Japan
- Student Laboratory, Faculty of Medicine, Tokushima University, Tokushima, Japan
| | - Masashi Yano
- Division of Molecular Neurobiology, Institute for Enzyme Research (KOSOKEN), Tokushima University, Tokushima, Japan
| | - Junji Chida
- Division of Molecular Neurobiology, Institute for Enzyme Research (KOSOKEN), Tokushima University, Tokushima, Japan
| | - Hideyuki Hara
- Division of Molecular Neurobiology, Institute for Enzyme Research (KOSOKEN), Tokushima University, Tokushima, Japan
| | - Nandita Rani Das
- Division of Molecular Neurobiology, Institute for Enzyme Research (KOSOKEN), Tokushima University, Tokushima, Japan
| | - Anders Nykjaer
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Suehiro Sakaguchi
- Division of Molecular Neurobiology, Institute for Enzyme Research (KOSOKEN), Tokushima University, Tokushima, Japan
- * E-mail: (SS); (KU)
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Sonati T, Reimann RR, Falsig J, Baral PK, O'Connor T, Hornemann S, Yaganoglu S, Li B, Herrmann US, Wieland B, Swayampakula M, Rahman MH, Das D, Kav N, Riek R, Liberski PP, James MNG, Aguzzi A. The toxicity of antiprion antibodies is mediated by the flexible tail of the prion protein. Nature 2013; 501:102-6. [PMID: 23903654 DOI: 10.1038/nature12402] [Citation(s) in RCA: 160] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Accepted: 06/21/2013] [Indexed: 12/17/2022]
Abstract
Prion infections cause lethal neurodegeneration. This process requires the cellular prion protein (PrP(C); ref. 1), which contains a globular domain hinged to a long amino-proximal flexible tail. Here we describe rapid neurotoxicity in mice and cerebellar organotypic cultured slices exposed to ligands targeting the α1 and α3 helices of the PrP(C) globular domain. Ligands included seven distinct monoclonal antibodies, monovalent Fab1 fragments and recombinant single-chain variable fragment miniantibodies. Similar to prion infections, the toxicity of globular domain ligands required neuronal PrP(C), was exacerbated by PrP(C) overexpression, was associated with calpain activation and was antagonized by calpain inhibitors. Neurodegeneration was accompanied by a burst of reactive oxygen species, and was suppressed by antioxidants. Furthermore, genetic ablation of the superoxide-producing enzyme NOX2 (also known as CYBB) protected mice from globular domain ligand toxicity. We also found that neurotoxicity was prevented by deletions of the octapeptide repeats within the flexible tail. These deletions did not appreciably compromise globular domain antibody binding, suggesting that the flexible tail is required to transmit toxic signals that originate from the globular domain and trigger oxidative stress and calpain activation. Supporting this view, various octapeptide ligands were not only innocuous to both cerebellar organotypic cultured slices and mice, but also prevented the toxicity of globular domain ligands while not interfering with their binding. We conclude that PrP(C) consists of two functionally distinct modules, with the globular domain and the flexible tail exerting regulatory and executive functions, respectively. Octapeptide ligands also prolonged the life of mice expressing the toxic PrP(C) mutant, PrP(Δ94-134), indicating that the flexible tail mediates toxicity in two distinct PrP(C)-related conditions. Flexible tail-mediated toxicity may conceivably play a role in further prion pathologies, such as familial Creutzfeldt-Jakob disease in humans bearing supernumerary octapeptides.
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Affiliation(s)
- Tiziana Sonati
- Institute of Neuropathology, University Hospital Zurich, Schmelzbergstrasse 12, CH-8091 Zurich, Switzerland
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Wills PR. Frameshifted prion proteins as pathological agents: quantitative considerations. J Theor Biol 2013; 325:52-61. [PMID: 23454079 DOI: 10.1016/j.jtbi.2013.02.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 02/14/2013] [Accepted: 02/18/2013] [Indexed: 11/17/2022]
Abstract
A quantitatively consistent explanation for the titres of infectivity found in a variety of prion-containing preparations is provided on the basis that the ætiological agents of transmissible spongiform encephalopathy comprise a very small population fraction of prion protein (PrP) variants, which contain frameshifted elements in their N-terminal octapeptide-repeat regions. A mechanism for the replication of frameshifted prions is described and calculations are performed to obtain estimates of the concentration of these PrP variants in normal and infected brain, as well as their enrichment in products of protein misfolding cyclic amplification. These calculations resolve the lack of proper quantitative correlation between measures of infectivity and the presence of conformationally-altered, protease-resistant variants of PrP. Experiments, which could confirm or eventually exclude the role of frameshifted variants in the ætiology of prion disease, are suggested.
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Affiliation(s)
- Peter R Wills
- Integrative Transcriptomics, Center for Bioinformatics Tübingen, University of Tübingen, Sand 14, Tübingen 72076, Germany.
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