Molecular Heterosis of Prion Protein β-Oligomers

Tahiri-Alaoui, Abdessamad; Sim, Valerie L.; Caughey, Byron; James, William

doi:10.1074/jbc.m606606200

Cited by 21 publications

(9 citation statements)

References 40 publications

(58 reference statements)

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“…These findings were not unprecedented. Previous studies revealed remarkable differences in behavior of small ␤-oligomeric species formed separately from two variants of human rPrP, 129V, and 129M and from their mixture (44). Taken together, our studies indicate that species specificity could be manifested at the nucleation step.…”

Section: Prpsupporting

confidence: 62%

Highly Promiscuous Nature of Prion Polymerization

Makarava

Lee

Ostapchenko

et al. 2007

Journal of Biological Chemistry

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The primary structure of the prion protein (PrP) is believed to be the key factor in regulating the species barrier of prion transmission. Because the strength of the species barrier was found to be affected by the prion strain, the extent to which the barrier can indeed be attributed to differences in the PrP primary structures of either donor and acceptor species remains unclear. In this study, we exploited the intrinsic property of PrP to polymerize spontaneously into disease-related amyloid conformations in the absence of a strain-specified template and analyzed polymerization of mouse and hamster full-length recombinant PrPs. Unexpectedly, we found no evidence of species specificity in cross-seeding polymerization assays. Even when both recombinant PrP variants were present in mixtures, preformed mouse or hamster fibrils displayed no selectivity in elongation reactions and consumed equally well both homologous and heterologous substrates. Analysis of individual fibrils revealed that fibrils can elongate in a bidirectional or unidirectional manner. Our work revealed that, in the absence of a cellular environment, post-translational modifications, or strain-specified conformational constraints, PrP fibrils are intrinsically promiscuous and capable of utilizing heterologous PrP variants as a substrate in a highly efficient manner. This study suggests that amyloid structures are capable of accommodating local perturbations arising because of a mismatch in amino acid sequences and highlights the promiscuous nature of the self-propagating activity of amyloid fibrils.

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Section: Prpsupporting

confidence: 62%

Highly Promiscuous Nature of Prion Polymerization

Makarava

Lee

Ostapchenko

et al. 2007

Journal of Biological Chemistry

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“…With respect to the faster RT-QuIC reaction kinetics using the Ha rPrP Sen (90–231) substrate, it is possible that the lack of the flexible N-terminal residues 23–89 destabilizes the native PrP Sen conformation, allowing it to more rapidly refold into the amyloid conformation under the influence of a prion seed. Alternatively, the N-terminal truncation might reduce the tendency of the substrate molecules to bind non-specifically to the reaction vessel or assume other off-pathway states, such as certain oligomers [ 28 ]. Temperature increases may also help to destabilize the Ha rPrP Sen substrate, making it more prone to seeded conversion.…”

Section: Discussionmentioning

confidence: 99%

Factors That Improve RT-QuIC Detection of Prion Seeding Activity

Orrú

Hughson

Groveman

et al. 2016

Viruses

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Rapid and sensitive detection of prions is important in managing prion diseases. The real-time quaking-induced conversion (RT-QuIC) assay for prion seeding activity has been applied to many prion diseases and provides for specific antemortem diagnostic testing. We evaluated RT-QuIC’s long-term consistency and varied multiple reaction parameters. Repeated assays of a single scrapie sample using multiple plate readers and recombinant prion protein (rPrPSen) substrates gave comparable results. N-terminal truncated hamster rPrPSen (residues 90–231) hastened both prion-seeded and prion-independent reactions but maintained a clear kinetic distinction between the two. Raising temperatures or shaking speeds accelerated RT-QuIC reactions without compromising specificity. When applied to nasal brushings from Creutzfeldt-Jakob disease patients, higher temperatures accelerated RT-QuIC kinetics, and the use of hamster rPrPSen (90–231) strengthened RT-QuIC responses. Elongation of shaking periods reduced scrapie-seeded reaction times, but continuous shaking promoted false-positive reactions. Furthermore, pH 7.4 provided for more rapid RT-QuIC reactions than more acidic pHs. Additionally, we show that small variations in the amount of sodium dodecyl sulfate (SDS) significantly impacted the assay. Finally, RT-QuIC performed in multiplate thermoshakers followed by fluorescence readings in separate plate readers enhanced assay throughput economically. Collectively, these results demonstrate improved speed, efficacy and practicality of RT-QuIC assays and highlight variables to be optimized for future applications.

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“…Therefore, the heterozygous inhibition is a universal feature of prion infections both in peripheral infection and central nervous system infection. The effect of PRNP polymorphisms have been studied recently in an in vitro model (17,33), in which fibril formation revealed the ␤-oligomer state (34). It was suggested that the ␤-oligomer was not on the pathway to amyloid formation and that the refolding and dissociation of the ␤-oligomer into the ␣-monomer most likely preceded the fibril formation.…”

Section: Discussionmentioning

confidence: 99%

Human Prion Protein (PrP) 219K Is Converted to PrPSc but Shows Heterozygous Inhibition in Variant Creutzfeldt-Jakob Disease Infection

Hizume

Kobayashi

Teruya

et al. 2009

Journal of Biological Chemistry

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Prion protein gene (PRNP) E219K is a human polymorphism commonly occurring in Asian populations but is rarely found in patients with sporadic Creutzfeldt-Jakob disease (CJD). Thus the polymorphism E219K has been considered protective against sporadic CJD. The corresponding mouse prion protein (PrP) polymorphism variant (mouse PrP 218K) is not converted to the abnormal isoform (PrP Sc ) and shows a dominant negative effect on wild-type PrP conversion. To define the conversion activity of this human molecule, we herein established knock-in mice with human PrP 219K and performed a series of transmission experiments with human prions. Surprisingly, the human PrP 219K molecule was converted to PrP Sc in variant CJD infection, and the conversion occurred more efficiently than PrP 219E molecule. Notably the knock-in mice with PRNP codon 219E/K showed the least efficient conversion compared with their hemizygotes with PRNP codon 219E/0 or codon 219K/0, or homozygotes with PRNP codon 219E/E or codon 219K/K. This phenomenon indicated heterozygous inhibition. This heterozygous inhibition was observed also in knock-in mice with PRNP codon 129M/V genotype. In addition to variant CJD infection, the human PrP 219K molecule is conversion-competent in transmission experiments with sporadic CJD prions. Therefore, the protective effect of PRNP E219K against sporadic CJD might be due to heterozygous inhibition.

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Molecular Heterosis of Prion Protein β-Oligomers

Cited by 21 publications

References 40 publications

Highly Promiscuous Nature of Prion Polymerization

Highly Promiscuous Nature of Prion Polymerization

Factors That Improve RT-QuIC Detection of Prion Seeding Activity

Human Prion Protein (PrP) 219K Is Converted to PrPSc but Shows Heterozygous Inhibition in Variant Creutzfeldt-Jakob Disease Infection

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