Distinct axial and lateral interactions within homologous filaments dictate the signaling specificity and order of the AIM2-ASC inflammasome

Nat Commun. 2021 May 12;12(1):2735. doi: 10.1038/s41467-021-23045-8.

Abstract

Inflammasomes are filamentous signaling platforms integral to innate immunity. Currently, little is known about how these structurally similar filaments recognize and distinguish one another. A cryo-EM structure of the AIM2PYD filament reveals that the architecture of the upstream filament is essentially identical to that of the adaptor ASCPYD filament. In silico simulations using Rosetta and molecular dynamics followed by biochemical and cellular experiments consistently demonstrate that individual filaments assemble bidirectionally. By contrast, the recognition between AIM2 and ASC requires at least one to be oligomeric and occurs in a head-to-tail manner. Using in silico mutagenesis as a guide, we also identify specific axial and lateral interfaces that dictate the recognition and distinction between AIM2 and ASC filaments. Together, the results here provide a robust framework for delineating the signaling specificity and order of inflammasomes.

Publication types

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

MeSH terms

  • CARD Signaling Adaptor Proteins / genetics
  • CARD Signaling Adaptor Proteins / metabolism*
  • Cryoelectron Microscopy
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • HEK293 Cells
  • Humans
  • Immunity, Innate / physiology*
  • Inflammasomes / metabolism*
  • Molecular Dynamics Simulation
  • Mutation / genetics
  • Protein Structure, Secondary
  • Signal Transduction / physiology

Substances

  • AIM2 protein, human
  • CARD Signaling Adaptor Proteins
  • DNA-Binding Proteins
  • Inflammasomes
  • PYCARD protein, human