IKKα negatively regulates ASC-dependent inflammasome activation

Nat Commun. 2014 Sep 30:5:4977. doi: 10.1038/ncomms5977.

Abstract

The inflammasomes are multiprotein complexes that activate caspase-1 in response to infections and stress, resulting in the secretion of pro-inflammatory cytokines. Here we report that IκB kinase α (IKKα) is a critical negative regulator of apoptosis-associated specklike protein containing a C-terminal caspase-activation-andrecruitment (CARD) domain (ASC)-dependent inflammasomes. IKKα controls the inflammasome at the level of the adaptor ASC, which interacts with IKKα in the nucleus of resting macrophages in an IKKα kinase-dependent manner. Loss of IKKα kinase activity results in inflammasome hyperactivation. Mechanistically, the downstream nuclear effector IKK-related kinase (IKKi) facilitates translocation of ASC from the nucleus to the perinuclear area during inflammasome activation. ASC remains under the control of IKKα in the perinuclear area following translocation of the ASC/IKKα complex. Signal 2 of NLRP3 activation leads to inhibition of IKKα kinase activity through the recruitment of PP2A, allowing ASC to participate in NLRP3 inflammasome assembly. Taken together, these findings reveal a IKKi-IKKα-ASC axis that serves as a common regulatory mechanism for ASC-dependent inflammasomes.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Apoptosis Regulatory Proteins / genetics
  • Apoptosis Regulatory Proteins / metabolism*
  • CARD Signaling Adaptor Proteins
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism
  • Down-Regulation*
  • Female
  • I-kappa B Kinase / genetics
  • I-kappa B Kinase / metabolism*
  • Inflammasomes / genetics
  • Inflammasomes / metabolism*
  • Macrophages / metabolism
  • Male
  • Mice
  • Mice, Knockout
  • NLR Family, Pyrin Domain-Containing 3 Protein
  • Protein Transport

Substances

  • Apoptosis Regulatory Proteins
  • CARD Signaling Adaptor Proteins
  • Carrier Proteins
  • Inflammasomes
  • NLR Family, Pyrin Domain-Containing 3 Protein
  • Nlrp3 protein, mouse
  • Pycard protein, mouse
  • Chuk protein, mouse
  • I-kappa B Kinase
  • Ikbke protein, mouse