Tuning Hsp104 specificity to selectively detoxify alpha-synuclein

Mack, K. L.; Kim, H.; Jackrel, M. E.; Lin, J.; DeNizio, J. E.; Yan, X.; Chuang, E.; Tariq, A.; Cupo, R. R.; Castellano, L. M.; Caldwell, K. A.; Caldwell, G. A.; Shorter, J.

doi:10.1101/2020.04.15.043935

bioRxiv · 10.1101/2020.04.15.043935

Tuning Hsp104 specificity to selectively detoxify alpha-synuclein

Mack, K. L.·Kim, H.·Jackrel, M. E.·Lin, J.·DeNizio, J. E.·Yan, X.·Chuang, E.·Tariq, A.·Cupo, R. R.·Castellano, L. M.·Caldwell, K. A.·Caldwell, G. A.·Shorter, J.

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Abstract

Hsp104 is an AAA+ protein disaggregase that solubilizes and reactivates proteins trapped in aggregated states. We have engineered potentiated Hsp104 variants to mitigate toxic misfolding of -synuclein, TDP-43, and FUS implicated in fatal neurodegenerative disorders. Though potent disaggregases, these enhanced Hsp104 variants lack substrate specificity, and can have unfavorable off-target effects. Here, to lessen off-target effects, we engineer substrate-specific Hsp104 variants. By altering Hsp104 pore loops that engage substrate, we disambiguate Hsp104 variants that selectively suppress -synuclein toxicity but not TDP-43 or FUS toxicity. Remarkably, -synuclein-specific Hsp104 variants emerge that mitigate -synuclein toxicity via distinct ATPase-dependent mechanisms, involving -synuclein disaggregation or detoxification of -synuclein conformers without disaggregation. Importantly, both types of -synuclein-specific Hsp104 variant reduce dopaminergic neurodegeneration in a C. elegans model of Parkinsons disease more effectively than non-specific variants. We suggest that increasing the substrate specificity of enhanced disaggregases could be applied broadly to tailor therapeutics for neurodegenerative disease.

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Mack, K. L., Kim, H., Jackrel, M. E., Lin, J., DeNizio, J. E., Yan, X., Chuang, E., Tariq, A., Cupo, R. R., Castellano, L. M., Caldwell, K. A., Caldwell, G. A., Shorter, J.. 2020-04-16. Tuning Hsp104 specificity to selectively detoxify alpha-synuclein. https://doi.org/10.1101/2020.04.15.043935

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