GSDMD membrane pore formation constitutes the mechanism of pyroptotic cell death
Author affiliations
Lorenzo Sborgi1,†, Sebastian Rühl1,†, Estefania Mulvihill2, Joka Pipercevic1, Rosalie Heilig1, Henning Stahlberg1, Christopher J Farady3, Daniel J Müller2, Petr Broz*,1 and Sebastian Hiller*,1
1Biozentrum, University of Basel, Basel, Switzerland
2Department of Biosystems Science and Engineering, Eidgenössische Technische Hochschule (ETH) Zurich, Basel, Switzerland
3Novartis Institutes for BioMedical Research Forum 1, Basel, Switzerland
↵* Corresponding author. Tel: +41 6126 72342; E‐mail: petr.broz@unibas.ch
Corresponding author. Tel: +41 6126 72082; E‐mail: sebastian.hiller@unibas.ch
↵† These authors contributed equally to this work
DOI 10.15252/embj.201694696 | Published online 14.07.2016
The EMBO Journal (2016) e201694696
Abstract
Pyroptosis is a lytic type of cell death that is initiated by inflammatory caspases. These caspases are activated within multi‐protein inflammasome complexes that assemble in response to pathogens and endogenous danger signals. Pyroptotic cell death has been proposed to proceed via the formation of a plasma membrane pore, but the underlying molecular mechanism has remained unclear. Recently, gasdermin D (GSDMD), a member of the ill‐characterized gasdermin protein family, was identified as a caspase substrate and an essential mediator of pyroptosis. GSDMD is thus a candidate for pyroptotic pore formation. Here, we characterize GSDMD function in live cells and in vitro. We show that the N‐terminal fragment of caspase‐1‐cleaved GSDMD rapidly targets the membrane fraction of macrophages and that it induces the formation of a plasma membrane pore. In vitro, the N‐terminal fragment of caspase‐1‐cleaved recombinant GSDMD tightly binds liposomes and forms large permeability pores. Visualization of liposome‐inserted GSDMD at nanometer resolution by cryo‐electron and atomic force microscopy shows circular pores with variable ring diameters around 20 nm. Overall, these data demonstrate that GSDMD is the direct and final executor of pyroptotic cell death.
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