Syntaxin-6 delays prion protein fibril formation and prolongs presence of toxic aggregation intermediates
- MRC Prion Unit, United Kingdom
Abstract
Prions replicate via the autocatalytic conversion of cellular prion protein (PrPC) into fibrillar assemblies of misfolded PrP. While this process has been extensively studied in vivo and in vitro, non-physiological reaction conditions of fibril formation in vitro have precluded the identification and mechanistic analysis of cellular proteins, which may alter PrP self-assembly and prion replication. Here, we have developed a fibril formation assay for recombinant murine and human PrP (23-231) under near-native conditions (NAA) to study the effect of cellular proteins, which may be risk factors or potential therapeutic targets in prion disease. Genetic screening suggests that variants that increase syntaxin-6 expression in the brain (gene: STX6) are risk factors for sporadic Creutzfeldt-Jakob disease (CJD). Analysis of the protein in NAA revealed, counterintuitively, that syntaxin-6 is a potent inhibitor of PrP fibril formation. It significantly delayed the lag phase of fibril formation at highly sub-stoichiometric molar ratios. However, when assessing toxicity of different aggregation time points to primary neurons, syntaxin-6 prolonged the presence of neurotoxic PrP species. Electron microscopy and super-resolution fluorescence microscopy revealed that, instead of highly ordered fibrils, in the presence of syntaxin-6 PrP formed less-ordered aggregates containing syntaxin-6. These data strongly suggest that the protein can directly alter the initial phase of PrP self-assembly and, uniquely, can act as an 'anti-chaperone', which promotes toxic aggregation intermediates by inhibiting fibril formation.
Data availability
All data generated or analysed during this study and all used analysis scripts have been uploaded to Mendeley data and are available to the public under doi: 10.17632/yggpkrgnx8.1
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Syntaxin 6 delays prion protein fibril formation and prolongs presence of toxic aggregation intermediatesMendeley Data, doi: 10.17632/yggpkrgnx8.1.
Article and author information
Author details
Funding
National Institute of Neurological Disorders and Stroke (1R21NS101588-01A1)
- Jan Bieschke
Medical Research Council (MC_UU_00024/6)
- Daljit Sangar
- Mark Batchelor
- Graham S Jackson
- Jan Bieschke
Medical Research Council (MRC Prion Unit Graduate Programme)
- Elizabeth Hill
- Kezia Jack
- Beenaben Mistry
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Animal experimentation: Work with animals was performed under the licence granted by the UK Home Office (Project Licences 70/6454 and 70/7274) and conformed to University College London institutional and ARRIVE guidelines.
Copyright
© 2024, Sangar et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Syntaxin-6 delays prion protein fibril formation and prolongs presence of toxic aggregation intermediates
eLife 13:e83320.
https://doi.org/10.7554/eLife.83320
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