The Ras GTPase-activating-like protein IQGAP1 bridges Gasdermin D to the ESCRT system to promote IL-1β release via exosomes

EMBO J. 2023 Jan 4;42(1):e110780. doi: 10.15252/embj.2022110780. Epub 2022 Nov 14.

Abstract

IL-1β can exit the cytosol as an exosomal cargo following inflammasome activation in intestinal epithelial cells (IECs) in a Gasdermin D (GSDMD)-dependent manner. The mechanistic connection linking inflammasome activation and the biogenesis of exosomes has so far remained largely elusive. Here, we report the Ras GTPase-activating-like protein IQGAP1 functions as an adaptor, bridging GSDMD to the endosomal sorting complexes required for transport (ESCRT) machinery to promote the biogenesis of pro-IL-1β-containing exosomes in response to NLPR3 inflammasome activation. We identified IQGAP1 as a GSDMD-interacting protein through a non-biased proteomic analysis. Functional investigation indicated the IQGAP1-GSDMD interaction is required for LPS and ATP-induced exosome release. Further analysis revealed that IQGAP1 serves as an adaptor which bridges GSDMD and associated IL-1β complex to Tsg101, a component of the ESCRT complex, and enables the packaging of GSDMD and IL-1β into exosomes. Importantly, this process is dependent on an LPS-induced increase in GTP-bound CDC42, a small GTPase known to activate IQGAP1. Taken together, this study reveals IQGAP1 as a link between inflammasome activation and GSDMD-dependent, ESCRT-mediated exosomal release of IL-1β.

Keywords: ESCRT; GSDMD; IQGAP1; exosome; inflammasome.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Endosomal Sorting Complexes Required for Transport / genetics
  • Endosomal Sorting Complexes Required for Transport / metabolism
  • Exosomes* / metabolism
  • Gasdermins
  • Inflammasomes* / metabolism
  • Interleukin-1beta / metabolism
  • Intracellular Signaling Peptides and Proteins / genetics
  • Intracellular Signaling Peptides and Proteins / metabolism
  • Lipopolysaccharides / pharmacology
  • Proteomics
  • Pyroptosis
  • ras Proteins / metabolism

Substances

  • IQ motif containing GTPase activating protein 1
  • Inflammasomes
  • Intracellular Signaling Peptides and Proteins
  • Gasdermins
  • ras Proteins
  • Lipopolysaccharides
  • Endosomal Sorting Complexes Required for Transport
  • Interleukin-1beta