351
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Cereghetti GM, Schweiger A, Glockshuber R, Van Doorslaer S. Electron paramagnetic resonance evidence for binding of Cu(2+) to the C-terminal domain of the murine prion protein. Biophys J 2001; 81:516-25. [PMID: 11423433 PMCID: PMC1301530 DOI: 10.1016/s0006-3495(01)75718-9] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Transmissible spongiform encephalopathies in mammals are believed to be caused by scrapie form of prion protein (PrP(Sc)), an abnormal, oligomeric isoform of the monomeric cellular prion protein (PrP(C)). One of the proposed functions of PrP(C) in vivo is a Cu(II) binding activity. Previous studies revealed that Cu(2+) binds to the unstructured N-terminal PrP(C) segment (residues 23-120) through conserved histidine residues. Here we analyzed the Cu(II) binding properties of full-length murine PrP(C) (mPrP), of its isolated C-terminal domain mPrP(121-231) and of the N-terminal fragment mPrP(58-91) in the range of pH 3-8 with electron paramagnetic resonance spectroscopy. We find that the C-terminal domain, both in its isolated form and in the context of the full-length protein, is capable of interacting with Cu(2+). Three Cu(II) coordination types are observed for the C-terminal domain. The N-terminal segment mPrP(58-91) binds Cu(2+) only at pH values above 5.0, whereas both mPrP(121-231) and mPrP(23-231) already show identical Cu(II) coordination in the pH range 3-5. As the Cu(2+)-binding N-terminal segment 58-91 is not required for prion propagation, our results open the possibility that Cu(2+) ions bound to the C-terminal domain are involved in the replication of prions, and provide the basis for further analytical studies on the specificity of Cu(II) binding by PrP.
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Affiliation(s)
- G M Cereghetti
- Institute of Molecular Biology and Biophysics, Swiss Federal Institute of Technology, Hönggerberg, CH-8093 Zurich, Switzerland
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352
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Requena JR, Groth D, Legname G, Stadtman ER, Prusiner SB, Levine RL. Copper-catalyzed oxidation of the recombinant SHa(29-231) prion protein. Proc Natl Acad Sci U S A 2001; 98:7170-5. [PMID: 11404462 PMCID: PMC34641 DOI: 10.1073/pnas.121190898] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Metal-catalyzed oxidation may result in structural damage to proteins and has been implicated in aging and disease, including neurological disorders such as Alzheimer's disease and amyotrophic lateral sclerosis. The selective modification of specific amino acid residues with high metal ion affinity leads to subtle structural changes that are not easy to detect but may have dramatic consequences on physical and functional properties of the oxidized protein molecules. PrP contains a histidine-rich octarepeat domain that binds copper. Because copper-binding histidine residues are particularly prone to metal-catalyzed oxidation, we investigated the effect of this reaction on the recombinant prion protein SHaPrP(29-231). Using Cu2+/ascorbate, we oxidized SHaPrP(29-231) in vitro. Oxidation was demonstrated by liquid chromatography/mass spectrometry, which showed the appearance of protein species of higher mass, including increases in multiples of 16, characteristic of oxygen incorporation. Digestion studies using Lys C indicate that the 29-101 region, which includes the histidine-containing octarepeats, is particularly affected by oxidation. Oxidation was time- and copper concentration-dependent and was evident with copper concentrations as low as 1 microM. Concomitant with oxidation, SHaPrP(29-231) suffered aggregation and precipitation, which was nearly complete after 15 min, when the prion protein was incubated at 37 degrees C with a 6-fold molar excess of Cu2+. These findings indicate that PrP, a copper-binding protein, may be particularly susceptible to metal-catalyzed oxidation and that oxidation triggers an extensive structural transition leading to aggregation.
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Affiliation(s)
- J R Requena
- Laboratory of Biochemistry, National Heart, Lung, and Blood Institute, National Institutes of Health, 50 South Drive, Room 2351 MSC 8012, Bethesda, MD 20892-8012, USA.
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353
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Curtain CC, Ali F, Volitakis I, Cherny RA, Norton RS, Beyreuther K, Barrow CJ, Masters CL, Bush AI, Barnham KJ. Alzheimer's disease amyloid-beta binds copper and zinc to generate an allosterically ordered membrane-penetrating structure containing superoxide dismutase-like subunits. J Biol Chem 2001; 276:20466-73. [PMID: 11274207 DOI: 10.1074/jbc.m100175200] [Citation(s) in RCA: 497] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Amyloid beta peptide (Abeta) is the major constituent of extracellular plaques and perivascular amyloid deposits, the pathognomonic neuropathological lesions of Alzheimer's disease. Cu(2+) and Zn(2+) bind Abeta, inducing aggregation and giving rise to reactive oxygen species. These reactions may play a deleterious role in the disease state, because high concentrations of iron, copper, and zinc have been located in amyloid in diseased brains. Here we show that coordination of metal ions to Abeta is the same in both aqueous solution and lipid environments, with His(6), His(13), and His(14) all involved. At Cu(2+)/peptide molar ratios >0.3, Abeta coordinated a second Cu(2+) atom in a highly cooperative manner. This effect was abolished if the histidine residues were methylated at N(epsilon)2, indicating the presence of bridging histidine residues, as found in the active site of superoxide dismutase. Addition of Cu(2+) or Zn(2+) to Abeta in a negatively charged lipid environment caused a conformational change from beta-sheet to alpha-helix, accompanied by peptide oligomerization and membrane penetration. These results suggest that metal binding to Abeta generated an allosterically ordered membrane-penetrating oligomer linked by superoxide dismutase-like bridging histidine residues.
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Affiliation(s)
- C C Curtain
- Biomolecular Research Institute, 343 Royal Parade, Parkville, Victoria 3052, Australia
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354
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Kramer ML, Kratzin HD, Schmidt B, Römer A, Windl O, Liemann S, Hornemann S, Kretzschmar H. Prion protein binds copper within the physiological concentration range. J Biol Chem 2001; 276:16711-9. [PMID: 11278306 DOI: 10.1074/jbc.m006554200] [Citation(s) in RCA: 203] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The prion protein is known to be a copper-binding protein, but affinity and stoichiometry data for the full-length protein at a physiological pH of 7 were lacking. Furthermore, it was unknown whether only the highly flexible N-terminal segment with its octarepeat region is involved in copper binding or whether the structured C-terminal domain is also involved. Therefore we systematically investigated the stoichiometry and affinity of copper binding to full-length prion protein PrP(23-231) and to different N- and C-terminal fragments using electrospray ionization mass spectrometry and fluorescence spectroscopy. Our data indicate that the unstructured N-terminal segment is the cooperative copper-binding domain of the prion protein. The prion protein binds up to five copper(II) ions with half-maximal binding at approximately 2 microm. This argues strongly for a direct role of the prion protein in copper metabolism, since it is almost saturated at about 5 microm, and the exchangeable copper pool concentration in blood is about 8 microm.
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Affiliation(s)
- M L Kramer
- Department of Neuropathology, Georg August University of Göttingen, Robert-Koch-Strasse 40, 37075 Göttingen, Germany.
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355
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Abstract
The prion protein is a cell surface glyco-protein expressed by neurones. Its function has remained elusive until it was recently shown to be a copper binding protein. There is now strong evidence that the prion protein has a role in normal brain copper metabolism. Prion protein expression alters copper uptake into cells and enhances copper incorporation into superoxide dismutase. Furthermore the prion protein itself can act as a superoxide dismutase. One aspect of prion disease is the conversion of functional prion protein into an aggregated amyloid. This conversion may alter the function of the prion protein or abolish it. These results suggest that prion disease may involve disturbance to brain copper homeostasis.
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Affiliation(s)
- D R Brown
- Department of Biochemistry, Cambridge University, Cambridge, UK.
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356
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Martins VR, Mercadante AF, Cabral AL, Freitas AR, Castro RM. Insights into the physiological function of cellular prion protein. Braz J Med Biol Res 2001; 34:585-95. [PMID: 11323744 DOI: 10.1590/s0100-879x2001000500005] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Prions have been extensively studied since they represent a new class of infectious agents in which a protein, PrPsc (prion scrapie), appears to be the sole component of the infectious particle. They are responsible for transmissible spongiform encephalopathies, which affect both humans and animals. The mechanism of disease propagation is well understood and involves the interaction of PrPsc with its cellular isoform (PrPc) and subsequently abnormal structural conversion of the latter. PrPc is a glycoprotein anchored on the cell surface by a glycosylphosphatidylinositol moiety and expressed in most cell types but mainly in neurons. Prion diseases have been associated with the accumulation of the abnormally folded protein and its neurotoxic effects; however, it is not known if PrPc loss of function is an important component. New efforts are addressing this question and trying to characterize the physiological function of PrPc. At least four different mouse strains in which the PrP gene was ablated were generated and the results regarding their phenotype are controversial. Localization of PrPc on the cell membrane makes it a potential candidate for a ligand uptake, cell adhesion and recognition molecule or a membrane signaling molecule. Recent data have shown a potential role for PrPc in the metabolism of copper and moreover that this metal stimulates PrPc endocytosis. Our group has recently demonstrated that PrPc is a high affinity laminin ligand and that this interaction mediates neuronal cell adhesion and neurite extension and maintenance. Moreover, PrPc-caveolin-1 dependent coupling seems to trigger the tyrosine kinase Fyn activation. These data provide the first evidence for PrPc involvement in signal transduction.
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Affiliation(s)
- V R Martins
- Centro de Tratamento e Pesquisa, Hospital do Câncer, Universidade de São Paulo, São Paulo, SP, Brasil
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357
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Quaglio E, Chiesa R, Harris DA. Copper converts the cellular prion protein into a protease-resistant species that is distinct from the scrapie isoform. J Biol Chem 2001; 276:11432-8. [PMID: 11278539 DOI: 10.1074/jbc.m009666200] [Citation(s) in RCA: 137] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Several lines of evidence have suggested that copper ions play a role in the biology of both PrP(C) and PrP(Sc), the normal and pathologic forms of the prion protein. To further investigate this intriguing connection, we have analyzed how copper ions affect the biochemical properties of PrP(C) extracted from the brains of transgenic mice and from transfected cells. We report that the metal rapidly and reversibly induces PrP(C) to become protease-resistant and detergent-insoluble. Although these two properties are commonly associated with PrP(Sc), we demonstrate using a conformation-dependent immunoassay that copper-treated PrP is structurally distinct from PrP(Sc). The effect of copper requires the presence of at least one of the five octapeptide repeats normally present in the N-terminal half of the protein, consistent with the idea that the metal alters the biochemical properties of PrP by directly binding to this region. These results suggest potential roles for copper in prion diseases, as well as in the physiological function of PrP(C).
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Affiliation(s)
- E Quaglio
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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358
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Yokoyama T, Kimura KM, Ushiki Y, Yamada S, Morooka A, Nakashiba T, Sassa T, Itohara S. In vivo conversion of cellular prion protein to pathogenic isoforms, as monitored by conformation-specific antibodies. J Biol Chem 2001; 276:11265-71. [PMID: 11152682 DOI: 10.1074/jbc.m008734200] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The central event in prion disease is thought to be conformational conversion of the cellular isoform of prion protein (PrP(C)) to the insoluble isoform PrP(Sc). We generated polyclonal and monoclonal antibodies by immunizing PrP(C)-null mice with native PrP(C). All seven monoclonal antibodies (mAbs) immunoprecipitated PrP(C), but they immunoprecipitated PrP(Sc) weakly or not at all, thereby indicating preferential reactivities to PrP(C) in solution. Immunoprecipitation using these mAbs revealed a marked loss of PrP(C) in brains at the terminal stage of illness. Histoblot analyses using these polyclonal antibodies in combination of pretreatment of blots dissociated PrP(C) and PrP(Sc) in situ and consistently demonstrated the decrease of PrP(C) at regions where PrP(Sc) accumulated. Interestingly, same mAbs showed immunohistochemical reactivities to abnormal isoforms. One group of mAbs showed reactivity to materials that accumulated in astrocytes, while the other group did so to amorphous plaques in neuropil. Epitope mapping indicated that single mAbs have reactivities to multiple epitopes, thus implying dual specificities. This suggests the importance of octarepeats as a part of PrP(C)-specific conformation. Our observations support the notion that loss of function of PrP(C) may partly underlie the pathogenesis of prion diseases. The conversion of PrP(C) to PrP(Sc) may involve multiple steps at different sites.
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Affiliation(s)
- T Yokoyama
- National Institute of Animal Health, Tsukuba, Ibaraki 305-0856, Japan, Nippi Research Institute of Biomatrix, Adachi, Tokyo 120-8601, Japan
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359
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Kretzschmar HA, Tings T, Madlung A, Giese A, Herms J. Function of PrP(C) as a copper-binding protein at the synapse. ARCHIVES OF VIROLOGY. SUPPLEMENTUM 2001:239-49. [PMID: 11214928 DOI: 10.1007/978-3-7091-6308-5_23] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The prion protein (PrP(C)) shows cooperative copper binding of the N-terminal octarepeat (PHGGGWGO) x4. In brain homogenates, PrP(C) is found in highest concentration in synaptosomal fractions. Mice devoid of PrP(C) (Prnp0/0 mice) show synaptosomal copper concentrations diminished by 50% as compared to normal mice. PrP(C) in the synaptic cleft may serve as a copper buffer. Alternatively it may play a role in the re-uptake of copper into the presynapse or may be of structural importance for the N-terminus and thus may influence binding of PrP(C) to other proteins.
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Affiliation(s)
- H A Kretzschmar
- Institute of Neuropathology, University of Göttingen, Germany
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360
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Perera WS, Hooper NM. Ablation of the metal ion-induced endocytosis of the prion protein by disease-associated mutation of the octarepeat region. Curr Biol 2001; 11:519-23. [PMID: 11413003 DOI: 10.1016/s0960-9822(01)00147-6] [Citation(s) in RCA: 158] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The neurodegenerative spongiform encephalopathies, or prion diseases, are characterized by the conversion of the normal cellular form of the prion protein PrP(C) to a pathogenic form, PrP(Sc) [1]. There are four copies of an octarepeat PHGG(G/S)WGQ that specifically bind Cu(2+) ions within the N-terminal half of PrP(C) [2--4]. This has led to proposals that prion diseases may, in part, be due to abrogation of the normal cellular role of PrP(C) in copper homeostasis [5]. Here, we show that murine PrP(C) is rapidly endocytosed upon exposure of neuronal cells to physiologically relevant concentrations of Cu(2+) or Zn(2+), but not Mn(2+). Deletion of the four octarepeats or mutation of the histidine residues (H68/76 dyad) in the central two repeats abolished endocytosis, indicating that the internalization of PrP(C) is governed by metal binding to the octarepeats. Furthermore, a mutant form of PrP that contains nine additional octarepeats and is associated with familial prion disease [6] failed to undergo Cu(2+)-mediated endocytosis. For the first time, these results provide evidence that metal ions can promote the endocytosis of a mammalian prion protein in neuronal cells and that neurodegeneration associated with some prion diseases may arise from the ablation of this function due to mutation of the octarepeat region.
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Affiliation(s)
- W S Perera
- School of Biochemistry and Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
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361
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Leclerc E, Peretz D, Ball H, Sakurai H, Legname G, Serban A, Prusiner SB, Burton DR, Williamson R. Immobilized prion protein undergoes spontaneous rearrangement to a conformation having features in common with the infectious form. EMBO J 2001; 20:1547-54. [PMID: 11285219 PMCID: PMC145482 DOI: 10.1093/emboj/20.7.1547] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2000] [Revised: 02/09/2001] [Accepted: 02/09/2001] [Indexed: 11/14/2022] Open
Abstract
It is hypothesized that infectious prions are generated as the cellular form of the prion protein (PrP(C)) undergoes pronounced conformational change under the direction of an infectious PrP(Sc) template. Conversion to the infectious conformer is particularly associated with major structural rearrangement in the central portion of the protein (residues 90-120), which has an extended flexible structure in the PrP(C) isoform. Using a panel of recombinant antibodies reactive with different parts of PrP, we show that equivalent major structural rearrangements occur spontaneously in this region of PrP immobilized on a surface. In contrast, regions more towards the termini of the protein remain relatively unaltered. The rearrangements occur even under conditions where individual PrP molecules should not contact one another. The propensity of specific unstructured regions of PrP to spontaneously undergo large and potentially deleterious conformational changes may have important implications for prion biology.
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Affiliation(s)
- Estelle Leclerc
- Departments of
Immunology and Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, Institute for Neurodegenerative Diseases and Departments of Neurology and Biochemistry and Biophysics, University of California, San Francisco, CA 94143, USA Corresponding authors e-mail: or
| | - David Peretz
- Departments of
Immunology and Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, Institute for Neurodegenerative Diseases and Departments of Neurology and Biochemistry and Biophysics, University of California, San Francisco, CA 94143, USA Corresponding authors e-mail: or
| | - Haydn Ball
- Departments of
Immunology and Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, Institute for Neurodegenerative Diseases and Departments of Neurology and Biochemistry and Biophysics, University of California, San Francisco, CA 94143, USA Corresponding authors e-mail: or
| | - Hiroshi Sakurai
- Departments of
Immunology and Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, Institute for Neurodegenerative Diseases and Departments of Neurology and Biochemistry and Biophysics, University of California, San Francisco, CA 94143, USA Corresponding authors e-mail: or
| | - Giuseppe Legname
- Departments of
Immunology and Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, Institute for Neurodegenerative Diseases and Departments of Neurology and Biochemistry and Biophysics, University of California, San Francisco, CA 94143, USA Corresponding authors e-mail: or
| | - Ana Serban
- Departments of
Immunology and Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, Institute for Neurodegenerative Diseases and Departments of Neurology and Biochemistry and Biophysics, University of California, San Francisco, CA 94143, USA Corresponding authors e-mail: or
| | - Stanley B. Prusiner
- Departments of
Immunology and Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, Institute for Neurodegenerative Diseases and Departments of Neurology and Biochemistry and Biophysics, University of California, San Francisco, CA 94143, USA Corresponding authors e-mail: or
| | - Dennis R. Burton
- Departments of
Immunology and Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, Institute for Neurodegenerative Diseases and Departments of Neurology and Biochemistry and Biophysics, University of California, San Francisco, CA 94143, USA Corresponding authors e-mail: or
| | - R.Anthony Williamson
- Departments of
Immunology and Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, Institute for Neurodegenerative Diseases and Departments of Neurology and Biochemistry and Biophysics, University of California, San Francisco, CA 94143, USA Corresponding authors e-mail: or
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362
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Herms JW, Tings T, Dunker S, Kretzschmar HA. Prion protein affects Ca2+-activated K+ currents in cerebellar purkinje cells. Neurobiol Dis 2001; 8:324-30. [PMID: 11300727 DOI: 10.1006/nbdi.2000.0369] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The prion protein (PrPC) has a primary role in the pathogenesis of transmissible spongiform encephalopathies. Its physiological function is not known yet. Altered late afterhyperpolarization has been observed in hippocampal CA1 pyramidal cells of prion protein-deficient mice (Prnp(0/0) mice) presumably caused by a disruption of Ca2+-activated K+ currents. An alteration of these currents has been recently described in scrapie-infected animals, and loss of function of PrPC has been put forward as one possible pathophysiological mechanism in prion diseases. This work focuses on patch-clamp studies of Ca2+-activated K+ currents in cerebellar Purkinje cells in the slice preparation of Prnp(0/0) mice as well as of transgenic mice. A significant correlation between PrPC expression in Purkinje cells and the maximal amplitude of TEA-insensitive Ca2+-activated K+ currents was observed, with reduced current amplitudes in Prnp(0/0) mice and a rescue of the phenotype in transgenic mice where PrPC had been reintroduced. Further studies of the intracellular free calcium concentration revealed an alteration of the maximal increase of intracellular calcium concentration with depolarization in the Prnp(0/0) mouse Purkinje cells. These data provide strong evidence that Ca2+-activated K+ currents in Prnp(0/0) mice are reduced due to an alteration of intracellular calcium homeostasis.
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Affiliation(s)
- J W Herms
- Department of Neuropathology, Georg-August Universität Göttingen, Robert-Koch-Strasse 40, Göttingen, 37075, Germany
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363
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Jansen GH, Vogelaar CF, Elshof SM. Distribution of cellular prion protein in normal human cerebral cortex--does it have relevance to Creutzfeldt-Jakob disease? Clin Chem Lab Med 2001; 39:294-8. [PMID: 11388651 DOI: 10.1515/cclm.2001.045] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Creutzfeldt-Jakob disease and bovine spongiform encephalopathy are the best known forms of prion diseases. A basis for their pathogenesis is the transformation of normal prion protein to abnormal prion protein. This would mean that either loss of normal function or a gain of a toxic function of the prion protein would play a major role. Since the prime target for Creutzfeldt-Jakob disease in humans is the neocortex, and the intracortical distribution of the destructive process in prion diseases appears not to be haphazard, it may be that a clear cortical study of normal prion protein production in the premorbid human neocortex might contribute to insight in the pathogenesis of prion diseases. As no such study is available, we performed a detailed study in normal human cortex using immunohistochemistry for prion protein, in both frozen and vibratomised tissue, and in situ hybridisation for prion protein mRNA. We have found normal prion protein production mainly in the upper cortical neurons in neocortex and Purkinje cells in the cerebellum. This finding implicates that normal prion protein is more important as an anti-apoptotic signal in disease than abnormal prion protein is as a toxic substance.
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Affiliation(s)
- G H Jansen
- Department of Pathology, University Medical Center Utrecht, The Netherlands.
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364
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Liu T, Zwingman T, Li R, Pan T, Wong BS, Petersen RB, Gambetti P, Herrup K, Sy MS. Differential expression of cellular prion protein in mouse brain as detected with multiple anti-PrP monoclonal antibodies. Brain Res 2001; 896:118-29. [PMID: 11277980 DOI: 10.1016/s0006-8993(01)02050-9] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The normal cellular prion protein (PrP(C)) plays an essential role in the development of prion diseases. Indirect evidence has suggested that different PrP(C) glycoforms may be expressed in different brain regions and perform distinct functions. However, due to a lack of monoclonal antibodies (Mabs) that are specific for mouse PrP(C), the expression of PrP(C) in the mouse brain has not been studied in great detail. We used Mabs specific for either the N-terminus or the C-terminus of the mouse PrP(C) to study its expression in the mouse brain by immunoblotting and immunohistochemistry. Immunoblotting studies demonstrated that the expression of PrP(C) differed quantitatively as well as qualitatively in different regions of the brain. The anti-C-terminus Mabs reacted with all three molecular weight bands of PrP(C); the anti-N-terminus Mabs only reacted with the 39-42 kDa PrP(C). The results from immunohistochemical staining revealed the spatial distribution of PrP(C) in the mouse brain, which were consistent with that from immunoblotting. Although expression of PrP(C) has been reported to be required for long-term survival of Purkinje cells, we were unable to detect PrP(C) in the Purkinje cell layer in the cerebellum with multiple anti-PrP Mabs. Our findings suggest that PrP(C) variants, i.e. various glycoforms and truncated forms, might be specifically expressed in different regions of mouse brain and might have different functions.
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Affiliation(s)
- T Liu
- Institute of Pathology, Case Western Reserve University, School of Medicine, 10900 Euclid Ave., Cleveland, OH 44106-1712, USA
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365
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Liu T, Li R, Wong BS, Liu D, Pan T, Petersen RB, Gambetti P, Sy MS. Normal cellular prion protein is preferentially expressed on subpopulations of murine hemopoietic cells. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 166:3733-42. [PMID: 11238614 DOI: 10.4049/jimmunol.166.6.3733] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We studied the expression of normal cellular prion protein (PrP(C)) in mouse lymphoid tissues with newly developed mAbs to PrP(C). Most of the mature T and B cells in the peripheral lymphoid organs do not express PrP(C). In contrast, most thymocytes are PrP(C+). In the bone marrow, erythroid cells and maturing granulocytes are PrP(C+). Approximately 50% of the cells in the region of small lymphocytes and progenitor cells also express PrP(C). Most of these PrP(C+) cells are CD43(+), but B220(-), surface IgM(-) (sIgM(-)), and IL-7R(-), a phenotype that belongs to cells not yet committed to the B cell lineage. Another small group of the PrP(C+) cell are B220(+), and some of these are also sIgM(+). The majority of the B220(+) cells, however, are PrP(C-). Therefore, PrP(C) is preferentially expressed in early bone marrow progenitor cells and subsets of maturing B cells. Supporting this interpretation is our observation that stimulation of bone marrow cells in vitro with PMA results in a decrease in the number of PrP(C+)B220(-) cells with a corresponding increase of sIgM(+)B220(high) mature B cells. This result suggests that the PrP(C+)B220(-) cells are potential progenitors. Furthermore, in the bone marrow of Rag-1(-/-) mice, there are an increased number of PrP(C+)B220(-) cells, and most of the developmentally arrested pro-B cells in these mice are PrP(C+). Collectively, these results suggest that PrP(C) is expressed preferentially in immature T cells in the thymus and early progenitor cells in the bone marrow, and the expression of PrP(C) is regulated during hemopoietic differentiation.
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Affiliation(s)
- T Liu
- Institute of Pathology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
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366
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Alonso DO, DeArmond SJ, Cohen FE, Daggett V. Mapping the early steps in the pH-induced conformational conversion of the prion protein. Proc Natl Acad Sci U S A 2001; 98:2985-9. [PMID: 11248018 PMCID: PMC30593 DOI: 10.1073/pnas.061555898] [Citation(s) in RCA: 144] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2000] [Indexed: 11/18/2022] Open
Abstract
Under certain conditions, the prion protein (PrP) undergoes a conformational change from the normal cellular isoform, PrP(C), to PrP(Sc), an infectious isoform capable of causing neurodegenerative diseases in many mammals. Conversion can be triggered by low pH, and in vivo this appears to take place in an endocytic pathway and/or caveolae-like domains. It has thus far been impossible to characterize the conformational change at high resolution by experimental methods. Therefore, to investigate the effect of acidic pH on PrP conformation, we have performed 10-ns molecular dynamics simulations of PrP(C) in water at neutral and low pH. The core of the protein is well maintained at neutral pH. At low pH, however, the protein is more dynamic, and the sheet-like structure increases both by lengthening of the native beta-sheet and by addition of a portion of the N terminus to widen the sheet by another two strands. The side chain of Met-129, a polymorphic codon in humans associated with variant Creutzfeldt-Jakob disease, pulls the N terminus into the sheet. Neutralization of Asp-178 at low pH removes interactions that inhibit conversion, which is consistent with the Asp-178-Asn mutation causing human prion diseases.
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Affiliation(s)
- D O Alonso
- Department of Medicinal Chemistry, University of Washington, Seattle, WA 98195-7610, USA
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367
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White AR, Huang X, Jobling MF, Barrow CJ, Beyreuther K, Masters CL, Bush AI, Cappai R. Homocysteine potentiates copper- and amyloid beta peptide-mediated toxicity in primary neuronal cultures: possible risk factors in the Alzheimer's-type neurodegenerative pathways. J Neurochem 2001; 76:1509-20. [PMID: 11238735 DOI: 10.1046/j.1471-4159.2001.00178.x] [Citation(s) in RCA: 174] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Oxidative stress may have an important role in the progression of neurodegenerative disorders such as Alzheimer's disease (AD) and prion diseases. Oxidative damage could result from interactions between highly reactive transition metals such as copper (Cu) and endogenous reducing and/or oxidizing molecules in the brain. One such molecule, homocysteine, a thiol-containing amino acid, has previously been shown to modulate Cu toxicity in HeLa and endothelial cells in vitro. Due to a possible link between hyperhomocysteinemia and AD, we examined whether interaction between homocysteine and Cu could potentiate Cu neurotoxicity. Primary mouse neuronal cultures were treated with homocysteine and either Cu (II), Fe (II or III) or Zn (II). Homocysteine was shown to selectively potentiate toxicity from low micromolar concentrations of Cu. The toxicity of homocysteine/Cu coincubation was dependent on the ability of homocysteine to reduce Cu (II) as reflected by the inhibition of toxicity with the Cu (I)-specific chelator, bathocuproine disulphonate. This was supported by data showing that homocysteine reduced Cu (II) more effectively than cysteine or methionine but did not reduce Fe (III) to Fe (II). Homocysteine also generated high levels of hydrogen peroxide in the presence of Cu (II) and promoted Abeta/Cu-mediated hydrogen peroxide production and neurotoxicity. The potentiation of metal toxicity did not involve excitotoxicity as ionotropic glutamate receptor antagonists had no effect on neurotoxicity. Homocysteine alone also had no effect on neuronal glutathione levels. These studies suggest that increased copper and/or homocysteine levels in the elderly could promote significant oxidant damage to neurons and may represent additional risk factor pathways which conspire to produce AD or related neurodegenerative conditions.
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Affiliation(s)
- A R White
- Department of Pathology, The University of Melbourne, Victoria, Australia.
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368
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Mo H, Moore RC, Cohen FE, Westaway D, Prusiner SB, Wright PE, Dyson HJ. Two different neurodegenerative diseases caused by proteins with similar structures. Proc Natl Acad Sci U S A 2001; 98:2352-7. [PMID: 11226243 PMCID: PMC30142 DOI: 10.1073/pnas.051627998] [Citation(s) in RCA: 133] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The downstream prion-like protein (doppel, or Dpl) is a paralog of the cellular prion protein, PrP(C). The two proteins have approximately 25% sequence identity, but seem to have distinct physiologic roles. Unlike PrP(C), Dpl does not support prion replication; instead, overexpression of Dpl in the brain seems to cause a completely different neurodegenerative disease. We report the solution structure of a fragment of recombinant mouse Dpl (residues 26-157) containing a globular domain with three helices and a small amount of beta-structure. Overall, the topology of Dpl is very similar to that of PrP(C). Significant differences include a marked kink in one of the helices in Dpl, and a different orientation of the two short beta-strands. Although the two proteins most likely arose through duplication of a single ancestral gene, the relationship is now so distant that only the structures retain similarity; the functions have diversified along with the sequence.
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Affiliation(s)
- H Mo
- Department of Molecular Biology and Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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369
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Van Doorslaer S, Cereghetti GM, Glockshuber R, Schweiger A. Unraveling the Cu2+ Binding Sites in the C-Terminal Domain of the Murine Prion Protein: A Pulse EPR and ENDOR Study. J Phys Chem B 2001. [DOI: 10.1021/jp003115y] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Sabine Van Doorslaer
- Laboratory of Physical Chemistry, ETH Zentrum, CH-8092 Zurich, Switzerland, and Institute of Molecular Biology and Biophysics, ETH Zurich Hönggerberg, CH-8093 Zurich, Switzerland
| | - Grazia M. Cereghetti
- Laboratory of Physical Chemistry, ETH Zentrum, CH-8092 Zurich, Switzerland, and Institute of Molecular Biology and Biophysics, ETH Zurich Hönggerberg, CH-8093 Zurich, Switzerland
| | - Rudi Glockshuber
- Laboratory of Physical Chemistry, ETH Zentrum, CH-8092 Zurich, Switzerland, and Institute of Molecular Biology and Biophysics, ETH Zurich Hönggerberg, CH-8093 Zurich, Switzerland
| | - Arthur Schweiger
- Laboratory of Physical Chemistry, ETH Zentrum, CH-8092 Zurich, Switzerland, and Institute of Molecular Biology and Biophysics, ETH Zurich Hönggerberg, CH-8093 Zurich, Switzerland
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370
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Abstract
Copper is an essential element in all living organisms, serving as a cofactor for many important proteins and enzymes. Metallochaperone proteins deliver copper ions to specific physiological partners by direct protein-protein interactions. The Atx1-like chaperones transfer copper to intracellular copper transporters, and the CCS chaperones shuttle copper to copper,zinc superoxide dismutase. Crystallographic studies of these two copper chaperone families have provided insights into metal binding and target recognition by metallochaperones and have led to detailed molecular models for the copper transfer mechanism.
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Affiliation(s)
- A C Rosenzweig
- Departments of Biochemistry, Molecular Biology, and Cell Biology and of Chemistry, Northwestern University, Evanston, Illinois 60208, USA.
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371
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McMahon HE, Mangé A, Nishida N, Créminon C, Casanova D, Lehmann S. Cleavage of the amino terminus of the prion protein by reactive oxygen species. J Biol Chem 2001; 276:2286-91. [PMID: 11060296 DOI: 10.1074/jbc.m007243200] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Relatively limited information is available on the processing and function of the normal cellular prion protein, PrP(C). Here it is reported for the first time that PrP(C) undergoes a site-specific cleavage of the octapeptide repeat region of the amino terminus on exposure to reactive oxygen species. This cleavage was both copper- and pH-dependent and was retarded by the presence of other divalent metal ions. The oxidative state of the cell also decreased detection of full-length PrP(C) and increased detection of amino-terminally fragmented PrP(C) within cells. Such a post-translational modification has vast implications for PrP(C), in its processing, because such cleavage could alter further proteolysis, and in the formation of the scrapie isoform of the prion protein, PrP(Sc), because abnormal cleavage of PrP(Sc) occurs into the octapeptide repeat region.
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Affiliation(s)
- H E McMahon
- Institut de Génétique Humaine, CNRS U.P.R. 1142, 141 Rue de la Cardonille, 34396 Montpellier Cedex 5, France
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372
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Abstract
We have developed a method to affinity-purify mouse prion protein (PrP(c)) from mouse brain and cultured cells. PrP(c) from mouse brain bound three copper atoms; PrP(c) from cultured cells bound between one and four copper atoms depending on the availability of copper in the culture medium. Purified PrP(c) exhibited antioxidant activity, as determined by spectrophotometric assay. Incubation of PrP(c) with the neurotoxic peptide, PrP106-126, inactivated the superoxide dismutase-like activity. Culture experiments showed that PrP(c) protects cells against oxidative stress relative to the amount of copper it binds. These results suggest that PrP(c) is a copper-binding protein which can incorporate varying amounts of copper and exhibit protective antioxidant activity.
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Affiliation(s)
- D R Brown
- Department of Biochemistry, Cambridge University, Cambridge, UK.
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373
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Meyer RK, Lustig A, Oesch B, Fatzer R, Zurbriggen A, Vandevelde M. A monomer-dimer equilibrium of a cellular prion protein (PrPC) not observed with recombinant PrP. J Biol Chem 2000; 275:38081-7. [PMID: 10967124 DOI: 10.1074/jbc.m007114200] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Both the purified normal (protease-sensitive) isoform of the prion protein (PrP(C)) (Pergami, P., Jaffe, H., and Safar, J. (1996) Anal. Biochem. 236, 63-73) and recombinant prion protein (PrP) have been found to be in monomeric form (Mehlhorn, I., Groth, D., Stockel, J., Moffat, B., Reilly, D., Yansura, D., Willet, W. S., Baldwin, M., Fletterick, R., Cohen, F. E., Vandlen, R., Henner, D., and Prusiner, S. B. (1996) Biochemistry 35, 5528-5537; and this paper), and therefore PrP(C)-PrP(C) interactions were previously unknown. In this report we confirm recombinant PrP to be a monomer by analytical ultracentrifugation. However, by three lines of evidence (enzyme-linked immunosorbent assay (ELISA), cross-linking experiments, and size exclusion chromatography) we could also demonstrate that, under native conditions, at least part of the native bovine PrP(C) exists as a monomer-dimer equilibrium. A bovine PrP(C)-specific immuno-sandwich ELISA was developed and calibrated with recombinant PrP (Meyer, R. K., Oesch, B., Fatzer, R., Zurbriggen, A., and Vandevelde, M. (1999) J. Virol. 73, 9386-9392). By this ELISA we identified a distinct PrP(C) fraction and partially purified this protein. When serial dilutions of brain homogenate or partially purified PrP(C) were measured, using the peptide antibody C15S, a nonlinear dose-response curve was obtained. This nonlinearity was shown not to be due to an artifact of the procedure but to a monomer-dimer equilibrium of PrP(C) with preferential binding of the antibody to the dimer. From the curvature we could deduce the association constant (3.9 x 10(8) M(-1) at 37 degrees C). Accordingly, DeltaG degrees of the reaction was calculated (-48.6 kJ M(-1)), and DeltaH degrees (9.5 kJ M(-1)) as well as DeltaS degrees (0.2 kJ K(-1) M(-1)) were extrapolated from the van't Hoff plot. When serial dilutions of monomeric recombinant PrP were tested, only a straight line was obtained, supporting our hypothesis. Additional evidence of dimer formation was revealed by Western blotting of partially purified PrP(C) cross-linked by the homobifunctional cross-linker BS(3). Finally, size exclusion chromatography of partially purified PrP(C) fractions revealed an additional shoulder not observed with recombinant PrP. The difference in respect of dimer formation between native PrP(C) and recombinant PrP could be explained by the lack of glycosylation of the latter.
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Affiliation(s)
- R K Meyer
- TSE Reference Center, Institute of Animal Neurology, University of Bern, Bremgartenstrasse 109a, CH-3012 Bern, Switzerland.
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374
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Bonomo RP, Imperllizzeri G, Pappalardo G, Rizzarelli E, Tabbì G. Copper(II) binding modes in the prion octapeptide PHGGGWGQ: a spectroscopic and voltammetric study. Chemistry 2000; 6:4195-202. [PMID: 11128284 DOI: 10.1002/1521-3765(20001117)6:22<4195::aid-chem4195>3.0.co;2-2] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The N-terminal octapeptide repeat region of human prion protein (PrPc) is known to bind Cu(II). To investigate the binding modes of copper in PrPc, an octapeptide Ac-PHGGGWGQ-NH2 (1), which corresponds to an octa-repeat sequence, and a tetrapeptide Ac-HGGG-NH2 (2) have been synthesised. The copper(II) complexes formed with 1 and 2 have been studied by circular dichroism (CD) and electron spin resonance (ESR) spectroscopy. Both peptides form 1:1 complexes with Cu(II) at neutral and basic pH. CD, ESR and visible absorption spectra suggest a similar co-ordination sphere of the metal ion in both peptides, which at neutral pH consists of a square pyramidal geometry with three peptidic nitrogens and the imidazole nitrogen as donor atoms. Cyclic voltammetric measurements were used to confirm the geometrical features of these copper(II) complexes: the observation of negative redox potentials are in good agreement with the inferred geometry. All these results taken together suggest that peptide 1 provides a single metal binding site to which copper(II) binds strongly at neutral and basic pH and that the binding of the metal induces the formation of a stiffened structure in the HGGG peptide fragment.
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Affiliation(s)
- R P Bonomo
- Dipartimento di Scienze Chimiche, Università di Catania, Italy.
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375
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Gill AC, Ritchie MA, Hunt LG, Steane SE, Davies KG, Bocking SP, Rhie AG, Bennett AD, Hope J. Post-translational hydroxylation at the N-terminus of the prion protein reveals presence of PPII structure in vivo. EMBO J 2000; 19:5324-31. [PMID: 11032800 PMCID: PMC314005 DOI: 10.1093/emboj/19.20.5324] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The transmissible spongiform encephalopathies are characterized by conversion of a host protein, PrP(C) (cellular prion protein), to a protease-resistant isoform, PrP(Sc) (prion protein scrapie isoform). The importance of the highly flexible, N-terminal region of PrP has recently become more widely appreciated, particularly the biological activities associated with its metal ion-binding domain and its potential to form a poly(L-proline) II (PPII) helix. Circular dichroism spectroscopy of an N-terminal peptide, PrP(37-53), showed that the PPII helix is formed in aqueous buffer; as it also contains an Xaa-Pro-Gly consensus sequence, it may act as a substrate for the collagen-modifying enzyme prolyl 4-hydroxylase. Direct evidence for this modification was obtained by mass spectrometry and Edman sequencing in recombinant mouse PrP secreted from stably transfected Chinese hamster ovary cells. Almost complete conversion of proline to 4-hydroxyproline occurs specifically at residue Pro44 of this murine protein; the same hydroxylated residue was detected, at lower levels, in PrP(Sc) from the brains of scrapie-infected mice. Cation binding and/or post-translational hydroxylation of this region of PrP may regulate its role in the physiology and pathobiology of the cell.
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Affiliation(s)
- A C Gill
- Institute for Animal Health, Compton, Newbury, Berkshire, RG20 7NN, UK
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376
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Thompson A, White AR, McLean C, Masters CL, Cappai R, Barrow CJ. Amyloidogenicity and neurotoxicity of peptides corresponding to the helical regions of PrP(C). J Neurosci Res 2000; 62:293-301. [PMID: 11020222 DOI: 10.1002/1097-4547(20001015)62:2<293::aid-jnr14>3.0.co;2-y] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
An alpha-helical to beta-sheet conformational change in the prion protein, PrP(C), is believed to be causative in transmissible spongiform encephalopathies. Recent nuclear magnetic resonance structures of PrP(C) have identified three helical regions in the normal full-length protein. We have synthesised peptides corresponding to these helical regions (PrP144-154, helical region one; PrP178-193, helical region two; and PrP198-218, helical region three). Circular dichroism results show that the peptide corresponding to helical region one is unstructured, while peptides corresponding to the second and third helical regions have a high propensity to form beta-sheet structure in a pH-dependent manner in aqueous solutions. Peptides corresponding to the second helical region, PrP180-193 and PrP178-193, are the only ones that form amyloid by electron microscopy and congo red birefringence. PrP178-193 and the amyloidogenic Alzheimer's disease Abeta25-25 peptide were found to promote Cu (II)-induced lipid peroxidation and cytotoxicity in primary neuronal cultures, while PrP144-154, PrP198-218 and the nonamyloidogenic Abeta1-28 had no effect on Cu (II) toxicity. There was no increase in toxicity induced by PrP178-193 in cultures treated with Fe (II) or hydrogen peroxide, indicating a preferential modulatory effect on Cu (II) toxicity by PrP178-193. The data suggest that the PrP178-193 peptide has both structural and bioactive properties in common with Abeta25-35 and that the second putative helical region of PrP could be involved in modulation of Cu (II)-mediated toxicity in neurons during prion disease.
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Affiliation(s)
- A Thompson
- School of Chemistry, The University of Melbourne, Parkville, Victoria, Australia
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377
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Wong BS, Vénien-Bryan C, Williamson RA, Burton DR, Gambetti P, Sy MS, Brown DR, Jones IM. Copper refolding of prion protein. Biochem Biophys Res Commun 2000; 276:1217-24. [PMID: 11027613 DOI: 10.1006/bbrc.2000.3604] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
We have shown previously that normal mouse prion protein (MoPrP) binds copper ions during protein refolding and acquires antioxidant activity. In this report, we probe the structure of the copper refolded form of MoPrP to determine how copper binding alters the secondary and tertiary features of the protein. Circular dichroism showed that recombinant MoPrP prepared in the presence of copper (as Cu(++)) showed an increased signal in the 210-220 nm range of the spectrum. Changes in protein conformation were localised to the N-terminal region of MoPrP using a panel of antibodies to assess epitope accessibility. The copper refolded recombinant prion protein had reduced proteinase K (PK) sensitivity when compared to the non-copper liganded form. Reduced PK sensitivity was not due to aggregation however as high resolution electron microscopy showed a homogenous preparation with little aggregate when compared to the non-copper form. Finally, disruption of the single disulphide linkage in MoPrP significantly diminished the antioxidant activity of the copper refolded form suggesting that activity was not solely dependent on bound copper but also on a conformation enabled by the formation of the disulphide bond.
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Affiliation(s)
- B S Wong
- School of Animal and Microbial Sciences, Reading, RG6 6AH, United Kingdom
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378
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Abstract
The long-term, progressive decay of the central nervous system typifies prion diseases, a group of rare, transmissible maladies affecting humans, sheep, cattle and some other types of mammal. Little is known about the early molecular events in its pathogenesis but the diverse roles of PrP, the prion protein, in its destructive action have recently been re-emphasised.
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Affiliation(s)
- J Hope
- Institute for Animal Health, Berkshire RG20 7NN, Compton, UK.
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379
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Kim JH, Cho H, Ryu SE, Choi MU. Effects of metal ions on the activity of protein tyrosine phosphatase VHR: highly potent and reversible oxidative inactivation by Cu2+ ion. Arch Biochem Biophys 2000; 382:72-80. [PMID: 11051099 DOI: 10.1006/abbi.2000.1996] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The posttranslational regulation of protein tyrosine phosphatases (PTPs) has been suggested to have a crucial role in maintaining the phosphotyrosine level in cells. Here we examined the regulatory effects of metal ions on human dual-specificity vaccinia H1-related protein tyrosine phosphatase (VHR) in vitro. Among various metal ions examined, Fe3+, Cu2+, Zn2+, and Cd2+ exerted their inactivational effects on VHR, and Cu2+ is the most potent inactivator. The VHR activity inactivated by the metal ions except Cu2+ was significantly restored by EDTA. The efficacy of Cu2+ for the VHR inactivation was about 200-fold more potent than that of H2O2. Cu2+ also inactivated other PTPs including PTP1B and SHP-1. The Cu2+-mediated inactivation at the submicromolar range was eradicated by dithiothreitol treatment. The loss of VHR activity correlated with the decreased [14C]iodoacetate labeling of active-site cysteine, suggesting that Cu2+ brought about the oxidation of the active-site cysteine. On the contrary, Zn2+ that exerted an inactivational effect at millimolar concentrations appeared not directly linked to the active-site cysteine, as indicated by the fact that [14C]iodoacetate labeling was unaffected and that the effect of Zn2+ on the Y78F mutant was increased. The reduction potential of VHR was estimated to be -331 mV by utilizing the reversibility of the redox state of VHR. Thus, we conclude that the highly potent Cu2+ inactivation of VHR is a consequence of the oxidation of the active-site cysteine and the mode of Zn2+ inactivation is distinct from that of Cu2+.
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Affiliation(s)
- J H Kim
- School of Chemistry and Molecular Engineering and Center for Molecular Catalysis, Seoul National University, South Korea
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380
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Flechsig E, Shmerling D, Hegyi I, Raeber AJ, Fischer M, Cozzio A, von Mering C, Aguzzi A, Weissmann C. Prion protein devoid of the octapeptide repeat region restores susceptibility to scrapie in PrP knockout mice. Neuron 2000; 27:399-408. [PMID: 10985358 DOI: 10.1016/s0896-6273(00)00046-5] [Citation(s) in RCA: 227] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Mice devoid of PrP are resistant to scrapie and fail to replicate the agent. Introduction of transgenes expressing PrP into such mice restores susceptibility to scrapie. We find that truncated PrP devoid of the five copper binding octarepeats still sustains scrapie infection; however, incubation times are longer and prion titers and protease-resistant PrP are about 30-fold lower than in wild-type mice. Surprisingly, brains of terminally ill animals show no histopathology typical for scrapie. However, in the spinal cord, infectivity, gliosis, and motor neuron loss are as in scrapie-infected wild-type controls. Thus, while the region comprising the octarepeats is not essential for mediating pathogenesis and prion replication, it modulates the extent of these events and of disease presentation.
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Affiliation(s)
- E Flechsig
- Institut für Molekularbiologie, Abteilung I, Universität Zürich, Switzerland
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381
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Martinez-Yamout M, Legge GB, Zhang O, Wright PE, Dyson HJ. Solution structure of the cysteine-rich domain of the Escherichia coli chaperone protein DnaJ. J Mol Biol 2000; 300:805-18. [PMID: 10891270 DOI: 10.1006/jmbi.2000.3923] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The solution structure of the cysteine-rich (CR) domain of Escherichia coli DnaJ has been solved by NMR methods. The structure of a 79 residue CR domain construct shows a novel fold with an overall V-shaped extended beta-hairpin topology. The CR domain is characterized by four C-X-X-C-X-G-X-G sequence motifs that bind two zinc ions. Residues in these two zinc modules show strong similarities in the grouping of resonances in the (15)N-(1)H HSQC spectrum and display pseudo-symmetry of the motifs in the calculated structures. The conformation of the cysteine residues coordinated to the zinc ion resembles that of the rubredoxin-knuckle, but there are significant differences in hydrogen bonding patterns in the two motifs. Zinc (15)N-(1)H HSQC titrations indicate that the fold of the isolated DnaJ CR domain is zinc-dependent and that one zinc module folds before the other. The C-X-X-C-X-G-X-G sequence motif is highly conserved in CR domains from a wide variety of species. The three-dimensional structure of the E. coli CR domain indicates that this sequence conservation is likely to result in a conserved structural motif.
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Affiliation(s)
- M Martinez-Yamout
- Department of Molecular Biology and Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA, 92037, USA
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382
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Satoh J, Kuroda Y, Katamine S. Gene expression profile in prion protein-deficient fibroblasts in culture. THE AMERICAN JOURNAL OF PATHOLOGY 2000; 157:59-68. [PMID: 10880376 PMCID: PMC1850192 DOI: 10.1016/s0002-9440(10)64517-8] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
To investigate the physiological function of the cellular isoform of prion protein (PrP(C)), the gene expression profile was studied by analyzing a cDNA expression array containing 597 clones of various functional classes in two distinct skin fibroblast cell lines designated SFK and SFH, established from PrP-deficient (PrP(-)(/-)) mice and PrP(+/+) mice, respectively. The cells were incubated in the culture medium with or without inclusion of basic fibroblast growth factor (bFGF). When SFK cells were compared with SFH cells in untreated conditions, the expression of 15 genes, including those essential for cell proliferation and adhesion, was reduced, whereas the expression of 27 genes, including those involved in the insulin-like growth factor-I (IGF-I) signaling pathway, was elevated. Northern blot analysis verified a significant down-regulation of the receptor tyrosine kinase substrate Eps8, cyclin D1, and CD44 mRNAs, and a substantial up-regulation of phosphatidylinositol 3-kinase p85, IGF-I, and serine protease inhibitor-2.2 mRNAs in SFK cells. The patterns of induction or reduction of gene expression after exposure to bFGF showed considerable overlap between both cell types. Furthermore, both Eps8 and CD44 mRNA levels were reduced greatly in the brain tissues of the cerebrum isolated from the PrP(-)(/-) mice. These results indicate that the disruption of the PrP gene resulted in an aberrant regulation of a battery of genes important for cell proliferation, differentiation, and survival, including those located in the Ras and Rac signaling pathways.
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Affiliation(s)
- J Satoh
- Division of Neurology, Department of Internal Medicine, Saga Medical School, Japan.
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383
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Qin K, Yang DS, Yang Y, Chishti MA, Meng LJ, Kretzschmar HA, Yip CM, Fraser PE, Westaway D. Copper(II)-induced conformational changes and protease resistance in recombinant and cellular PrP. Effect of protein age and deamidation. J Biol Chem 2000; 275:19121-31. [PMID: 10858456 DOI: 10.1074/jbc.275.25.19121] [Citation(s) in RCA: 128] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
While PrP(C) rearranges in the area of codons 104-113 to form PrP(Sc) during prion infections, the events that initiate sporadic Creutzfeldt-Jakob disease are undefined. As Cu(II) is a putative ligand for PrP(C) and has been implicated in the pathogenesis of Creutzfeldt-Jakob disease and other neurodegenerative diseases, we investigated the structural effects of binding. Incubation of brain microsomes with Cu(II) generated approximately 30-kDa proteinase K-resistant PrP. Cu(II) had little effect on fresh recombinant PrP23-231, but aged protein characterized by conversion of Asn-107 to Asp decreased alpha-helical content by approximately 30%, increased beta-sheet content 100%, formed aggregates, and acquired proteinase K resistance in the presence of Cu(II). These transitions took place without need for acid pH, organic solvents, denaturants, or reducing agents. Since conversion of Asn to Asp proceeds by a spontaneous pathway involving deamidation, our data suggest that covalent variants of PrP(C) arising in this manner may, in concert with Cu(II), generate PrP(Sc)-like species capable of initiating sporadic prion disease.
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Affiliation(s)
- K Qin
- Centre for Research in Neurodegenerative Diseases, Department of Medical Biophysics, Mass Spectrometry Laboratory, Modern Medicine Research Centre, Toronto, Ontario M 5S 3HS, Canada
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384
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Gilch S, Spielhaupter C, Schätzl HM. Shortest known prion protein allele in highly BSE-susceptible lemurs. Biol Chem 2000; 381:521-3. [PMID: 10937885 DOI: 10.1515/bc.2000.067] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
We describe the shortest prion protein allele known to date. Surprisingly, it is found as a polymorphism exactly in a species (prosimian lemurs) which seems highly susceptible to oral infection with BSE-derived prions. The truncation of the prion protein we found raises several questions. First, is the truncated octarepeat structure we describe, consisting of two octarepeats, still functional in copper binding? A second question is whether this truncation is related to the remarkable oral infectibility of lemurs with BSE-derived prions. And finally, one could argue that this genotype alone might favour development of a prion disease, even in the absence of exogenous infection.
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Affiliation(s)
- S Gilch
- Genecenter Munich, Max von Pettenkofer-Institute for Virology, Ludwig-Maximilians-University of Munich, Germany
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385
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Zulianello L, Kaneko K, Scott M, Erpel S, Han D, Cohen FE, Prusiner SB. Dominant-negative inhibition of prion formation diminished by deletion mutagenesis of the prion protein. J Virol 2000; 74:4351-60. [PMID: 10756050 PMCID: PMC111952 DOI: 10.1128/jvi.74.9.4351-4360.2000] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Polymorphic basic residues near the C terminus of the prion protein (PrP) in humans and sheep appear to protect against prion disease. In heterozygotes, inhibition of prion formation appears to be dominant negative and has been simulated in cultured cells persistently infected with scrapie prions. The results of nuclear magnetic resonance and mutagenesis studies indicate that specific substitutions at the C-terminal residues 167, 171, 214, and 218 of PrP(C) act as dominant-negative, inhibitors of PrP(Sc) formation (K. Kaneko et al., Proc. Natl. Acad. Sci. USA 94:10069-10074, 1997). Trafficking of substituted PrP(C) to caveaola-like domains or rafts by the glycolipid anchor was required for the dominant-negative phenotype; interestingly, amino acid replacements at multiple sites were less effective than single-residue substitutions. To elucidate which domains of PrP(C) are responsible for dominant-negative inhibition of PrP(Sc) formation, we analyzed whether N-terminally truncated PrP(Q218K) molecules exhibited dominant-negative effects in the conversion of full-length PrP(C) to PrP(Sc). We found that the C-terminal domain of PrP is not sufficient to impede the conversion of the full-length PrP(C) molecule and that N-terminally truncated molecules (with residues 23 to 88 and 23 to 120 deleted) have reduced dominant-negative activity. Whether the N-terminal region of PrP acts by stabilizing the C-terminal domain of the molecule or by modulating the binding of PrP(C) to an auxiliary molecule that participates in PrP(Sc) formation remains to be established.
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Affiliation(s)
- L Zulianello
- Institute for Neurodegenerative Diseases, University of California, San Francisco, California 94143, USA
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386
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Rezaei H, Marc D, Choiset Y, Takahashi M, Hui Bon Hoa G, Haertlé T, Grosclaude J, Debey P. High yield purification and physico-chemical properties of full-length recombinant allelic variants of sheep prion protein linked to scrapie susceptibility. EUROPEAN JOURNAL OF BIOCHEMISTRY 2000; 267:2833-9. [PMID: 10806380 DOI: 10.1046/j.1432-1033.2000.01347.x] [Citation(s) in RCA: 134] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Sheep susceptibility to scrapie is governed by polymorphisms at two major sites, codons 136 and 171, of the prp gene. To get more insight into the prion protein (PrP) sequence-linked basis of differential scrapie susceptibility, a high yield one-step method for the purification (over 99% final purity) of the full-length recombinant sheep PrP was developed, based on the affinity of the conserved octapeptide repeats for transition-metal cations. Thermal and chemical denaturation experiments and limited proteolysis studies were performed on the natural variants (A136R171, V136Q171 and A136Q171) and a recombinant PrP mutated at position 136 (V136R171). Results revealed the influence of mutations in positions 136 and 171 on the folding thermodynamic parameters and on the conformation of the C-terminal domain. Together, our results show that the VQ cellular protein linked to higher scrapie susceptibility is intrinsically more compact and/or stable than the resistance-linked AR counterpart. This might lead to a lower in vivo clearance rate of VQ and a consequently higher probability of occurrence of pathological events.
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Affiliation(s)
- H Rezaei
- Institut National de la Recherche Agronomique (INRA) Unité 806/EA2703, Muséum National d'Histoire Naturelle, Institut de Biologie Physico-Chimique, Paris, France
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387
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Abstract
Data are now rapidly accumulating to show that metallochemical reactions might be the common denominator underlying Alzheimer's disease, amyotrophic lateral sclerosis, prion diseases, cataracts, mitochondrial disorders and Parkinson's disease. In these disorders, an abnormal reaction between a protein and a redox-active metal ion (copper or iron) promotes the formation of reactive oxygen species or radicalization. It is especially intriguing how the powerful catalytic redox activity of antioxidant Cu/Zn-superoxide dismutase can convert into a pro-oxidant activity, a theme echoed in the recent proposal that Abeta and PrP, the proteins respectively involved in Alzheimer's disease and prion diseases, possess similar redox activities.
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Affiliation(s)
- A I Bush
- Laboratory for Oxidation Biology, Genetics and Aging Unit, Massachusetts General Hospital East, Charlestown, MA 02129, USA.
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388
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Wong BS, Clive C, Haswell SJ, Williamson RA, Burton DR, Gambetti P, Sy MS, Jones IM, Brown DR. Copper has differential effect on prion protein with polymorphism of position 129. Biochem Biophys Res Commun 2000; 269:726-31. [PMID: 10720484 DOI: 10.1006/bbrc.2000.2355] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The pathology of human prion diseases is affected by polymorphism at amino acid residue 129 of the prion protein gene. Recombinant mouse prion proteins mimicking either form of the polymorphism were prepared to examine their effect on the conformation and the level of superoxide dismutase (SOD) activity of the prion protein. Following the binding of copper atoms to prion protein, antibody mapping and CD analysis detected conformational differences between the two forms of protein. However, neither the level of copper binding nor the level of SOD activity associated with this form of prion protein altered with the identity of codon 129. These results suggest that in the holo-metal binding form of the protein, prion structure but not its SOD activity is affected by polymorphism at codon 129.
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Affiliation(s)
- B S Wong
- NERC Institute of Virology and Environmental Microbiology, Mansfield Road, Oxford, OX1 3SR, United Kingdom
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389
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Waggoner DJ, Drisaldi B, Bartnikas TB, Casareno RL, Prohaska JR, Gitlin JD, Harris DA. Brain copper content and cuproenzyme activity do not vary with prion protein expression level. J Biol Chem 2000; 275:7455-8. [PMID: 10713045 DOI: 10.1074/jbc.275.11.7455] [Citation(s) in RCA: 146] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Prion diseases are neurodegenerative disorders that result from conformational transformation of a normal cell surface glycoprotein, PrP(C), into a pathogenic isoform, PrP(Sc). Although the normal physiological function of PrP(C) has remained enigmatic, the recent observation that the protein binds copper ions with micromolar affinity suggests a possible role in brain copper metabolism. In this study, we have used mice that express 0, 1, and 10 times the normal level of PrP to assess the effect of PrP expression level on the amount of brain copper and on the properties of two brain cuproenzymes. Using mass spectrometry, we find that the amount of ionic copper in subcellular fractions from brain is similar in all three lines of mice. In addition, the enzymatic activities of Cu-Zn superoxide dismutase and cytochrome c oxidase in brain extracts are similar in these groups of animals, as is the incorporation of (64)Cu into Cu-Zn superoxide dismutase both in cultured cerebellar neurons and in vivo. Our results differ from those of another set of published studies, and they require a re-evaluation of the role of PrP(C) in copper metabolism.
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Affiliation(s)
- D J Waggoner
- Edward Mallinckrodt Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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390
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Brown DR, Hafiz F, Glasssmith LL, Wong BS, Jones IM, Clive C, Haswell SJ. Consequences of manganese replacement of copper for prion protein function and proteinase resistance. EMBO J 2000; 19:1180-6. [PMID: 10716918 PMCID: PMC305659 DOI: 10.1093/emboj/19.6.1180] [Citation(s) in RCA: 220] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The prion protein (PrP) binds copper and has antioxidant activity enhancing the survival of neurones in culture. The ability of the PrP to bind other cations was tested and it was found that only manganese could substitute for copper. Although initially manganese-loaded PrP exhibited similar structure and activity to copper-loaded PrP, after aging, manganese-loaded PrP became proteinase resistant and lost function. It was also found that manganese could be incorporated into PrP expressed by astrocytes and that this PrP was partially proteinase resistant. These results show that it is possible to generate proteinase-resistant PrP from cells and suggest a possible mechanism for the formation of the scrapie isoform of the PrP as generated in sporadic prion disease.
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Affiliation(s)
- D R Brown
- Department of Biochemistry, Tennis Court Road, Cambridge University, Cambridge CB2 1QW.
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391
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Whittal RM, Ball HL, Cohen FE, Burlingame AL, Prusiner SB, Baldwin MA. Copper binding to octarepeat peptides of the prion protein monitored by mass spectrometry. Protein Sci 2000; 9:332-43. [PMID: 10716185 PMCID: PMC2144551 DOI: 10.1110/ps.9.2.332] [Citation(s) in RCA: 188] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Electrospray ionization mass spectrometry (ESI-MS) was used to measure the binding of Cu2+ ions to synthetic peptides corresponding to sections of the sequence of the mature prion protein (PrP). ESI-MS demonstrates that Cu2+ is unique among divalent metal ions in binding to PrP and defines the location of the major Cu2+ binding site as the octarepeat region in the N-terminal domain, containing multiple copies of the repeat ProHisGlyGlyGlyTrpGlyGln. The stoichiometries of the complexes measured directly by ESI-MS are pH dependent: a peptide containing four octarepeats chelates two Cu2+ ions at pH 6 but four at pH 7.4. At the higher pH, the binding of multiple Cu2+ ions occurs with a high degree of cooperativity for peptides C-terminally extended to incorporate a fifth histidine. Dissociation constants for each Cu2+ ion binding to the octarepeat peptides, reported here for the first time, are mostly in the low micromolar range; for the addition of the third and fourth Cu2+ ions to the extended peptides at pH 7.4, K(D)'s are <100 nM. N-terminal acetylation of the peptides caused some reduction in the stoichiometry of binding at both pH's. Cu2+ also binds to a peptide corresponding to the extreme N-terminus of PrP that precedes the octarepeats, arguing that this region of the sequence may also make a contribution to the Cu2+ complexation. Although the structure of the four-octarepeat peptide is not affected by pH changes in the absence of Cu2+, as judged by circular dichroism, Cu2+ binding induces a modest change at pH 6 and a major structural perturbation at pH 7.4. It is possible that PrP functions as a Cu2+ transporter by binding Cu2+ ions from the extracellular medium under physiologic conditions and then releasing some or all of this metal upon exposure to acidic pH in endosomes or secondary lysosomes.
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Affiliation(s)
- R M Whittal
- Department of Pharmaceutical Chemistry, University of California San Francisco, 94143-0446, USA
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392
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Shiraishi N, Ohta Y, Nishikimi M. The octapeptide repeat region of prion protein binds Cu(II) in the redox-inactive state. Biochem Biophys Res Commun 2000; 267:398-402. [PMID: 10623631 DOI: 10.1006/bbrc.1999.1944] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The octapeptide repeat region of human prion protein is known to bind four Cu(II) ions per molecule. A peptide, Octa(4), representing this region was tested for inhibitory effects on copper-catalyzed oxidation of l-ascorbate or glutathione and on generation of OH(*) during the former reaction. The result indicated that the catalytic activity of the first Cu(II) ion bound to an Octa(4) molecule was completely suppressed. The valence state of the copper under reducing conditions was Cu(II), as determined by a newly developed method using bathocuproinedisulfonate under acidic conditions. Furthermore, it was shown that Escherichia coli cells expressing the octapeptide repeat region were significantly resistant to copper treatment compared with control cells. The results taken together indicate that prion protein can function to sequester copper ions in the redox-inactive state, rendering copper-induced generation of reactive oxygen species impossible.
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Affiliation(s)
- N Shiraishi
- Department of Biochemistry, Wakayama Medical College, Wakayama, 641-0012, Japan
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393
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Morillas M, Swietnicki W, Gambetti P, Surewicz WK. Membrane environment alters the conformational structure of the recombinant human prion protein. J Biol Chem 1999; 274:36859-65. [PMID: 10601237 DOI: 10.1074/jbc.274.52.36859] [Citation(s) in RCA: 219] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The prion protein (PrP) in a living cell is associated with cellular membranes. However, all previous biophysical studies with the recombinant prion protein have been performed in an aqueous solution. To determine the effect of a membrane environment on the conformational structure of PrP, we studied the interaction of the recombinant human prion protein with model lipid membranes. The protein was found to bind to acidic lipid-containing membrane vesicles. This interaction is pH-dependent and becomes particularly strong under acidic conditions. Spectroscopic data show that membrane binding of PrP results in a significant ordering of the N-terminal part of the molecule. The folded C-terminal domain, on the other hand, becomes destabilized upon binding to the membrane surface, especially at low pH. Overall, these results show that the conformational structure and stability of the recombinant human PrP in a membrane environment are substantially different from those of the free protein in solution. These observations have important implications for understanding the mechanism of the conversion between the normal (PrP(C)) and pathogenic (PrP(Sc)) forms of prion protein.
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Affiliation(s)
- M Morillas
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio 44106, USA
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394
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The Alzheimer's disease amyloid precursor protein modulates copper-induced toxicity and oxidative stress in primary neuronal cultures. J Neurosci 1999. [PMID: 10531420 DOI: 10.1523/jneurosci.19-21-09170.1999] [Citation(s) in RCA: 159] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The amyloid precursor protein (APP) of Alzheimer's disease can reduce copper (II) to copper (I) in a cell-free system potentially leading to increased oxidative stress in neurons. We used neuronal cultures derived from APP knock-out (APP(-/-)) and wild-type (WT) mice to examine the role of APP in copper neurotoxicity. WT cortical, cerebellar, and hippocampal neurons were significantly more susceptible than their respective APP(-/-) neurons to toxicity induced by physiological concentrations of copper but not by zinc or iron. There was no difference in copper toxicity between APLP2(-/-) and WT neurons, demonstrating specificity for APP-associated copper toxicity. Copper uptake was the same in WT and APP(-/-) neurons, suggesting APP may interact with copper to induce a localized increase in oxidative stress through copper (I) production. This was supported by significantly higher levels of copper-induced lipid peroxidation in WT neurons. Treatment of neuronal cultures with a peptide corresponding to the human APP copper-binding domain (APP142-166) potentiated copper but not iron or zinc toxicity. Incubation of APP142-166 with low-density lipoprotein (LDL) and copper resulted in significantly increased lipid peroxidation compared to copper and LDL alone. Substitution of the copper coordinating histidine residues with asparagines (APP142-166(H147N, H149N, H151N)) abrogated the toxic effects. A peptide corresponding to the zinc-binding domain (APP181-208) failed to induce copper or zinc toxicity in neuronal cultures. These data support a role for the APP copper-binding domain in APP-mediated copper (I) generation and toxicity in primary neurons, a process that has important implications for Alzheimer's disease and other neurodegenerative disorders.
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395
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Brown DR, Wong BS, Hafiz F, Clive C, Haswell SJ, Jones IM. Normal prion protein has an activity like that of superoxide dismutase. Biochem J 1999; 344 Pt 1:1-5. [PMID: 10548526 PMCID: PMC1220606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
We show here that mouse prion protein (PrP(C)) either as recombinant protein or immunoprecipitated from brain tissue has superoxide dismutase (SOD) activity. SOD activity was also associated with recombinant chicken PrP(C) confirming the evolutionary conserved phenotype suggested by sequence similarity. Acquisition of copper by PrP(C) during protein folding endowed SOD activity on the protein but the addition of copper following refolding did not. PrP(C) dependent SOD activity was abolished by deletion of the octapeptide-repeat region involved in copper binding. These results describe an enzymic function for PrP(C) consistent with its cellular distribution and suggest it has a direct role in cellular resistance to oxidative stress.
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Affiliation(s)
- D R Brown
- Department of Biochemistry, Tennis Court Road, University of Cambridge, Cambridge CB2 1QW, U.K.
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396
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Shaked Y, Rosenmann H, Talmor G, Gabizon R. A C-terminal-truncated PrP isoform is present in mature sperm. J Biol Chem 1999; 274:32153-8. [PMID: 10542251 DOI: 10.1074/jbc.274.45.32153] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
PrP(C), the normal isoform of the prion component PrP(Sc), is a 33-35-kDa glycophosphatidylinositol-anchored glycoprotein expressed in the plasma membrane of many cells and especially in the brain. The specific role of PrP(C) is unknown, although lately it has been shown to bind copper specifically. We show here that PrP(C) is present even in mature sperm cells, a polarized cell that retains only the minimal components required for DNA delivery, movement, and energy production. As opposed to PrP(C) in other cells, PrP in ejaculated sperm cells was truncated in its C terminus in the vicinity of residue 200. Sperm PrP, although membrane-bound, was not released by phosphatidylinositol phospholipase C as well as not localized in cholesterol-rich microdomains (rafts). Although no infertility was reported for PrP-ablated mice in normal situations, our results suggest that sperm cells originating from PrP-ablated mice were significantly more susceptible to high copper concentrations than sperm from wild type mice, allocating a protective role for PrP in specific stress situations related to copper toxicity. Since the functions performed by proteins in sperm cells are limited, these cells may constitute an ideal system to elucidate the function of PrP(C).
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Affiliation(s)
- Y Shaked
- Department of Neurology, Hadassah University Hospital, Jerusalem, 91120, Israel
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397
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Kanyo ZF, Pan KM, Williamson RA, Burton DR, Prusiner SB, Fletterick RJ, Cohen FE. Antibody binding defines a structure for an epitope that participates in the PrPC-->PrPSc conformational change. J Mol Biol 1999; 293:855-63. [PMID: 10543972 DOI: 10.1006/jmbi.1999.3193] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The X-ray crystallographic structures of the anti-Syrian hamster prion protein (SHaPrP) monoclonal Fab 3F4 alone, as well as the complex with its cognate peptide epitope (SHaPrP 104-113), have been determined to atomic resolution. The conformation of the decapeptide is an Omega-loop. There are substantial alterations in the antibody combining region upon epitope binding. The peptide binds in a U-shaped groove on the Fab surface, with the two specificity determinants, Met109 and Met112, penetrating deeply into separate hydrophobic cavities formed by the heavy and light chain complementarity-determining regions. In addition to the numerous contacts between the Fab and the peptide, two intrapeptide hydrogen bonds are observed, perhaps indicating the structure bound to the Fab exists transiently in solution. This provides the first structural information on a portion of the PrP N-terminal region observed to be flexible in the NMR studies of SHPrP 90-231, SHaPrP 29-231 and mouse PrP 23-231. Antibody characterization of the antigenic surfaces of PrPC and PrPSc identifies this flexible region as a component of the conformational rearrangement that is an essential feature of prion disease.
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Affiliation(s)
- Z F Kanyo
- Department of Neurology, University of California, San Francisco, CA 94143-0518, USA
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398
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White AR, Multhaup G, Maher F, Bellingham S, Camakaris J, Zheng H, Bush AI, Beyreuther K, Masters CL, Cappai R. The Alzheimer's disease amyloid precursor protein modulates copper-induced toxicity and oxidative stress in primary neuronal cultures. J Neurosci 1999; 19:9170-9. [PMID: 10531420 PMCID: PMC6782934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023] Open
Abstract
The amyloid precursor protein (APP) of Alzheimer's disease can reduce copper (II) to copper (I) in a cell-free system potentially leading to increased oxidative stress in neurons. We used neuronal cultures derived from APP knock-out (APP(-/-)) and wild-type (WT) mice to examine the role of APP in copper neurotoxicity. WT cortical, cerebellar, and hippocampal neurons were significantly more susceptible than their respective APP(-/-) neurons to toxicity induced by physiological concentrations of copper but not by zinc or iron. There was no difference in copper toxicity between APLP2(-/-) and WT neurons, demonstrating specificity for APP-associated copper toxicity. Copper uptake was the same in WT and APP(-/-) neurons, suggesting APP may interact with copper to induce a localized increase in oxidative stress through copper (I) production. This was supported by significantly higher levels of copper-induced lipid peroxidation in WT neurons. Treatment of neuronal cultures with a peptide corresponding to the human APP copper-binding domain (APP142-166) potentiated copper but not iron or zinc toxicity. Incubation of APP142-166 with low-density lipoprotein (LDL) and copper resulted in significantly increased lipid peroxidation compared to copper and LDL alone. Substitution of the copper coordinating histidine residues with asparagines (APP142-166(H147N, H149N, H151N)) abrogated the toxic effects. A peptide corresponding to the zinc-binding domain (APP181-208) failed to induce copper or zinc toxicity in neuronal cultures. These data support a role for the APP copper-binding domain in APP-mediated copper (I) generation and toxicity in primary neurons, a process that has important implications for Alzheimer's disease and other neurodegenerative disorders.
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Affiliation(s)
- A R White
- Department of Pathology, The University of Melbourne, Parkville, 3052 Victoria, Australia
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399
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Copper(II)–tripeptide complexes in aqueous solution. Effects of the C-terminal chelate ring size on the coordination structure of doubly deprotonated complex species. J Inorg Biochem 1999. [DOI: 10.1016/s0162-0134(99)00184-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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400
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Wright PE, Dyson HJ. Intrinsically unstructured proteins: re-assessing the protein structure-function paradigm. J Mol Biol 1999; 293:321-31. [PMID: 10550212 DOI: 10.1006/jmbi.1999.3110] [Citation(s) in RCA: 2200] [Impact Index Per Article: 88.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A major challenge in the post-genome era will be determination of the functions of the encoded protein sequences. Since it is generally assumed that the function of a protein is closely linked to its three-dimensional structure, prediction or experimental determination of the library of protein structures is a matter of high priority. However, a large proportion of gene sequences appear to code not for folded, globular proteins, but for long stretches of amino acids that are likely to be either unfolded in solution or adopt non-globular structures of unknown conformation. Characterization of the conformational propensities and function of the non-globular protein sequences represents a major challenge. The high proportion of these sequences in the genomes of all organisms studied to date argues for important, as yet unknown functions, since there could be no other reason for their persistence throughout evolution. Clearly the assumption that a folded three-dimensional structure is necessary for function needs to be re-examined. Although the functions of many proteins are directly related to their three-dimensional structures, numerous proteins that lack intrinsic globular structure under physiological conditions have now been recognized. Such proteins are frequently involved in some of the most important regulatory functions in the cell, and the lack of intrinsic structure in many cases is relieved when the protein binds to its target molecule. The intrinsic lack of structure can confer functional advantages on a protein, including the ability to bind to several different targets. It also allows precise control over the thermodynamics of the binding process and provides a simple mechanism for inducibility by phosphorylation or through interaction with other components of the cellular machinery. Numerous examples of domains that are unstructured in solution but which become structured upon binding to the target have been noted in the areas of cell cycle control and both transcriptional and translational regulation, and unstructured domains are present in proteins that are targeted for rapid destruction. Since such proteins participate in critical cellular control mechanisms, it appears likely that their rapid turnover, aided by their unstructured nature in the unbound state, provides a level of control that allows rapid and accurate responses of the cell to changing environmental conditions.
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Affiliation(s)
- P E Wright
- Department of Molecular Biology and Skaggs Institute of Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
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