Mechanism of membrane pore formation by human gasdermin‐D

• DOI: 10.15252/embj.201798321
• Publication Date: 2018-06-13T08:15:36Z
• Authors: Estefania Mulvihill; Lorenzo Sborgi; Stefania A Mari; Moritz Pfreundschuh; Sebastian Hiller; Daniel J Müller
• Keywords: 0303 health sciences; Cell Membrane; Intracellular Signaling Peptides and Proteins; Articles; Phosphate-Binding Proteins; Microscopy, Atomic Force; Time-Lapse Imaging; Recombinant Proteins; gasdermin-D pore assembly; Neoplasm Proteins; Protein Transport; 03 medical and health sciences; cell death; cell death; inflammation; gasdermin-D pore assembly; time-lapse high-resolution atomic force microscopy; transmission electron microscopy; inflammation; Caspases; Liposomes; transmission electron microscopy; Humans; Protein Multimerization; time-lapse high-resolution atomic force microscopy

Gasdermin‐D (GSDMD), a member of the gasdermin protein family, mediates pyroptosis in human and murine cells. Cleaved by inflammatory caspases, GSDMD inserts its N‐terminal domain (GSDMDNterm) into cellular membranes and assembles large oligomeric complexes permeabilizing the membrane. So far, the mechanisms of GSDMDNterm insertion, oligomerization, and pore formation are poorly understood. Here, we apply high‐resolution (≤ 2 nm) atomic force microscopy (AFM) to describe how GSDMDNterm inserts and assembles in membranes. We observe GSDMDNterm inserting into a variety of lipid compositions, among which phosphatidylinositide (PI(4,5)P2) increases and cholesterol reduces insertion. Once inserted, GSDMDNterm assembles arc‐, slit‐, and ring‐shaped oligomers, each of which being able to form transmembrane pores. This assembly and pore formation process is independent on whether GSDMD has been cleaved by caspase‐1, caspase‐4, or caspase‐5. Using time‐lapse AFM, we monitor how GSDMDNterm assembles into arc‐shaped oligomers that can transform into larger slit‐shaped and finally into stable ring‐shaped oligomers. Our observations translate into a mechanistic model of GSDMDNterm transmembrane pore assembly, which is likely shared within the gasdermin protein family.<br/>ISSN:0261-4189<br/>ISSN:1460-2075<br/>The EMBO Journal, 37 (14)<br/>