Mechanism of membrane pore formation by human gasdermin‐D. (13th June 2018)

• Record Type: Journal Article
• Authors: Mulvihill, Estefania; Sborgi, Lorenzo; Mari, Stefania A; Pfreundschuh, Moritz; Hiller, Sebastian; Müller, Daniel J
• Is Part Of: EMBO journal. Volume 37:Number 14(2018)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-06-13
• Subjects: cell death -- inflammation -- gasdermin‐D pore assembly -- time‐lapse high‐resolution atomic force microscopy -- transmission electron microscopy; Molecular biology -- Periodicals; 572.805
• DOI: 10.15252/embj.201798321
• Languages: English
• ISSNs: 0261-4189

Abstract

Abstract: 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 (GSDMD Nterm ) into cellular membranes and assembles large oligomeric complexes permeabilizing the membrane. So far, the mechanisms of GSDMD Nterm insertion, oligomerization, and pore formation are poorly understood. Here, we apply high‐resolution (≤ 2 nm) atomic force microscopy (AFM) to describe how GSDMD Nterm inserts and assembles in membranes. We observe GSDMD Nterm inserting into a variety of lipid compositions, among which phosphatidylinositide (PI(4, 5)P2) increases and cholesterol reduces insertion. Once inserted, GSDMD Nterm 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 GSDMD Nterm 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 GSDMD Nterm transmembrane pore assembly, which is likely shared within the gasdermin protein family. Synopsis: Gasdermin‐D, which mediates pyroptosis in human and murine cells, is directly observed inserting into lipid membranes and assembling arc‐, slit‐ and ring‐shaped oligomers. The observations translate into a mechanistic model of gasdermin‐D assembling transmembrane lytic pores. High‐resolution time‐lapse imaging of gasdermin‐D pore formation. Gasdermin‐D assembles arc‐, slit‐ and ring‐shaped oligomers. Arc‐ and slit‐shaped pores transform into stable ring‐shaped pores. Phosphatidylinositide (PI(4, 5)P2) increases gasdermin‐D pore formation. Cholesterol reduces gasdermin‐D pore formation. Abstract : High‐resolution atomic force microscopy shows how a pyroptosis‐mediating gasdermin protein inserts into lipid membranes and assembles arc‐, slit‐ and ring‐shaped oligomers.