USP3 deubiquitinates and stabilizes the adapter protein ASC to regulate inflammasome activation

Cell Mol Immunol. 2022 Oct;19(10):1141-1152. doi: 10.1038/s41423-022-00917-7. Epub 2022 Sep 1.


Inflammasomes are essential components of the innate immune system and its defense against infections, whereas the dysregulation of inflammasome activation has a detrimental effect on human health. The activation of inflammasomes is subjected to tight regulation to maintain immune homeostasis, yet the underlying mechanism remains elusive. Here, we identify USP3 as a direct deubiquitinating enzyme (DUB) for ASC, the central adapter mediating the assembly and activation of most inflammasomes. USP3 removes the K48-linked ubiquitination on ASC and strengthens its stability by blocking proteasomal degradation. Additionally, USP3 promotes inflammasome activation, and this function was confirmed in mouse models of aluminum (Alum)-induced peritonitis, F. novicida infection and flagellin-induced pneumonia in vivo. Our work unveils that USP3 functions as a key regulator of ASC ubiquitination and maintains the physiological role of ASC in mediating inflammasome activation, and we propose a new mechanism by which the ubiquitination of ASC regulates inflammasome activation.

Keywords: ASC; K48-linked ubiquitination; USP3; inflammasome; proteasomal degradation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / metabolism
  • Aluminum / metabolism
  • Animals
  • CARD Signaling Adaptor Proteins*
  • Deubiquitinating Enzymes / metabolism
  • Flagellin / metabolism
  • Humans
  • Inflammasomes* / metabolism
  • Mice
  • NLR Family, Pyrin Domain-Containing 3 Protein / metabolism
  • Ubiquitin-Specific Proteases / metabolism


  • Adaptor Proteins, Signal Transducing
  • CARD Signaling Adaptor Proteins
  • Inflammasomes
  • NLR Family, Pyrin Domain-Containing 3 Protein
  • Flagellin
  • Aluminum
  • Deubiquitinating Enzymes
  • USP3 protein, human
  • Ubiquitin-Specific Proteases