Cryo-electron tomography of ASC signalling sites in pyroptotic cells

Liu, Y.; Zhai, H.; Alemayehu, H.; Hopkins, L. J.; Borgeaud, A. C.; Heroven, C.; Howe, J. D.; Boulanger, J.; Bryant, C. E.; Modis, Y.

doi:10.1101/2021.09.20.461078

bioRxiv · 10.1101/2021.09.20.461078

Cryo-electron tomography of ASC signalling sites in pyroptotic cells

Liu, Y.·Zhai, H.·Alemayehu, H.·Hopkins, L. J.·Borgeaud, A. C.·Heroven, C.·Howe, J. D.·Boulanger, J.·Bryant, C. E.·Modis, Y.

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Abstract

NLRP3 induces caspase-1-dependent pyroptotic cell death to drive inflammation. Aberrant activity of NLRP3 occurs in many human diseases. NLRP3 activation induces ASC polymerization into a single, micron-scale perinuclear punctum. Higher resolution imaging of this signaling platform is needed to understand how it induces pyroptosis. Here, we apply correlative cryo-light microscopy and cryo-electron tomography to visualize ASC/caspase-1 in NLRP3-activated cells. The puncta are composed of branched ASC filaments, with a tubular core formed by the pyrin domain. Ribosomes and Golgi-like vesicles permeate the filament network, consistent with roles for these organelles in NLRP3 activation. Mitochondria are not associated with ASC but have outer-membrane discontinuities the same size as gasdermin D pores, consistent with our data showing gasdermin D associates with mitochondria and contributes to mitochondrial depolarization. One-Sentence SummaryElectron tomography of frozen cells reveals the ultrastructure of ASC specks and gasdermin D pores in adjacent mitochondria.

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Liu, Y., Zhai, H., Alemayehu, H., Hopkins, L. J., Borgeaud, A. C., Heroven, C., Howe, J. D., Boulanger, J., Bryant, C. E., Modis, Y.. 2021-09-20. Cryo-electron tomography of ASC signalling sites in pyroptotic cells. https://doi.org/10.1101/2021.09.20.461078

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