A conformational switch controlling the toxicity of the prion protein (original) (raw)
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Prion Infections and Anti-PrP Antibodies Trigger Converging Neurotoxic Pathways
PLoS pathogens, 2015
Prions induce lethal neurodegeneration and consist of PrPSc, an aggregated conformer of the cellular prion protein PrPC. Antibody-derived ligands to the globular domain of PrPC (collectively termed GDL) are also neurotoxic. Here we show that GDL and prion infections activate the same pathways. Firstly, both GDL and prion infection of cerebellar organotypic cultured slices (COCS) induced the production of reactive oxygen species (ROS). Accordingly, ROS scavenging, which counteracts GDL toxicity in vitro and in vivo, prolonged the lifespan of prion-infected mice and protected prion-infected COCS from neurodegeneration. Instead, neither glutamate receptor antagonists nor inhibitors of endoplasmic reticulum calcium channels abolished neurotoxicity in either model. Secondly, antibodies against the flexible tail (FT) of PrPC reduced neurotoxicity in both GDL-exposed and prion-infected COCS, suggesting that the FT executes toxicity in both paradigms. Thirdly, the PERK pathway of the unfold...
Rapid ex vivo reverse genetics identifies the essential determinants of prion protein toxicity
The cellular prion protein PrPC mediates the neurotoxicity of prions and other protein aggregates through poorly understood mechanisms. Antibody-derived ligands against the globular domain of PrPC (GDL) can also initiate neurotoxicity by inducing an intramolecular R208-H140 hydrogen bond (“H-latch”) between the α2-α3 and β2-α2 loops of PrPC. Importantly, GDL that suppress the H-latch prolong the life of prion-infected mice, suggesting that GDL toxicity and prion infections exploit convergent pathways. To define the structural underpinnings of these phenomena, we transduced nineteen individual PrPC variants to PrPC-deficient cerebellar organotypic cultured slices using adenovirus-associated viral vectors (AAV). We report that GDL toxicity requires a single N-proximal cationic residue (K27 or R27) within PrPC. Alanine substitution of K27 also prevented the toxicity of PrPC mutants that induce Shmerling syndrome, a neurodegenerative disease that is suppressed by co-expression of wild-t...
The EMBO Journal, 2011
Formation of aberrant protein conformers is a common pathological denominator of different neurodegenerative disorders, such as Alzheimer's disease or prion diseases. Moreover, increasing evidence indicates that soluble oligomers are associated with early pathological alterations and that oligomeric assemblies of different disease-associated proteins may share common structural features. Previous studies revealed that toxic effects of the scrapie prion protein (PrP Sc ), a b-sheet-rich isoform of the cellular PrP (PrP C ), are dependent on neuronal expression of PrP C . In this study, we demonstrate that PrP C has a more general effect in mediating neurotoxic signalling by sensitizing cells to toxic effects of various b-sheet-rich (b) conformers of completely different origins, formed by (i) heterologous PrP, (ii) amyloid b-peptide, (iii) yeast prion proteins or (iv) designed b-peptides. Toxic signalling via PrP C requires the intrinsically disordered N-terminal domain (N-PrP) and the GPI anchor of PrP. We found that the N-terminal domain is important for mediating the interaction of PrP C with b-conformers. Interestingly, a secreted version of N-PrP associated with b-conformers and antagonized their toxic signalling via PrP C . Moreover, PrP C -mediated toxic signalling could be blocked by an NMDA receptor antagonist or an oligomer-specific antibody. Our study indicates that PrP C can mediate toxic signalling of various b-sheet-rich conformers independent of infectious prion propagation, suggesting a pathophysiological role of the prion protein beyond of prion diseases.
The N-terminus of the prion protein is a toxic effector regulated by the C-terminus
eLife, 2017
PrP(C), the cellular isoform of the prion protein, serves to transduce the neurotoxic effects of PrP(Sc), the infectious isoform, but how this occurs is mysterious. Here, using a combination of electrophysiological, cellular, and biophysical techniques, we show that the flexible, N-terminal domain of PrP(C) functions as a powerful toxicity-transducing effector whose activity is tightly regulated in cis by the globular C-terminal domain. Ligands binding to the N-terminal domain abolish the spontaneous ionic currents associated with neurotoxic mutants of PrP, and the isolated N-terminal domain induces currents when expressed in the absence of the C-terminal domain. Anti-PrP antibodies targeting epitopes in the C-terminal domain induce currents, and cause degeneration of dendrites on murine hippocampal neurons, effects that entirely dependent on the effector function of the N-terminus. NMR experiments demonstrate intramolecular docking between N- and C-terminal domains of PrP(C), revea...
Soluble Dimeric Prion Protein Binds PrPSc In Vivo and Antagonizes Prion Disease
Cell, 2003
and familial human transmissible spongiform encephalopathies (TSEs) exhibit mutations of Prnp (Hsiao et al., 1 Institute of Neuropathology, Schmelzbergstrasse University Hospital of Zü rich 1989). PrP C is encoded by a single exon of the Prnp gene 2 Institute of Laboratory Animal Science Sternwartstrasse and is anchored to the cell surface by a glycosyl phosphatidyl inositol (GPI) residue. Its physiological function University of Zü rich CH-8091 Zü rich is still poorly understood (Behrens and Aguzzi, 2002). A soluble form of PrP C lacking the glycolipid moiety is Switzerland 3 Institute of Animal Neurology present in serum (Lopez et al., 1990; Perini et al., 1996; Tagliavini et al., 1992) and epididymal fluid (Gatti et al., University of Bern Bremgartenstr. 109a 2002). In primary cultures of splenocytes and cerebellar granule cells, a substantial amount of PrP C is shed after CH-3012 Bern Switzerland loss of the GPI anchor (Parizek et al., 2001).
Increased Proportions of C1 Truncated Prion Protein Protect Against Cellular M1000 Prion Infection
Journal of Neuropathology & Experimental Neurology, 2009
Prion disease pathogenesis is linked to the cell-associated propagation of misfolded protease-resistant conformers (PrP res) of the normal cellular prion protein (PrP C). Ongoing PrP C expression is the only known absolute requirement for successful prion disease transmission and PrP res propagation. Further typifying prion disease is selective neuronal dysfunction and loss, although the precise mechanisms underlying this are undefined. We utilized a single prion strain (M1000) and a range of neuronal and nonneuronal, PrP C endogenously expressing and transgenically modified overexpressing cell lines, to evaluate whether PrP C glycosylation patterns or constitutive N-terminal cleavage events may be determinants of sustained PrP res propagation. Our data demonstrates that relative proportions of full-length and C1 truncated PrP C are the most important characteristics influencing susceptibility to sustained M1000 prion infection, supporting PrP C >-cleavage as a protective event, which may contribute to the selective neuronal vulnerability observed in vivo.
A nine amino acid domain Is essential for mutant prion protein toxicity
2011
Transgenic mice expressing PrP molecules with several different internal deletions display spontaneous neurodegenerative phenotypes that can be dose-dependently suppressed by coexpression of wild-type PrP. Each of these deletions, including the largest one (Δ32-134), retains nine amino acids immediately following the signal peptide cleavage site (residues 23-31; KKRPKPGGW). These residues have been implicated in several biological functions of PrP, including endocytic trafficking and binding of glycosaminoglycans. We report here on our experiments to test the role of this domain in the toxicity of deleted forms of PrP. We find that transgenic mice expressing Δ23-134 PrP display no clinical symptoms or neuropathology, in contrast to mice expressing Δ32-134 PrP, suggesting that residues 23-31 are essential for the toxic phenotype. Using a newly developed cell culture assay, we narrow the essential region to amino acids 23-26, and we show that mutant PrP toxicity is not related to the role of the Nterminal residues in endocytosis or binding to endogenous glycosaminoglycans. However, we find that mutant PrP toxicity is potently inhibited by application of exogenous glycosaminoglycans, suggesting that the latter molecules block an essential interaction between the N-terminus of PrP and a membrane-associated target site. Our results demonstrate that a short segment containing positively charged amino acids at the N-terminus of PrP plays an essential role in mediating PrPrelated neurotoxicity. This finding identifies a protein domain that may serve as a drug target for amelioration of prion neurotoxicity.