A novel PAAD-containing protein that modulates NF-kappa B induction by cytokines tumor necrosis factor-alpha and interleukin-1beta

J Biol Chem. 2002 Sep 20;277(38):35333-40. doi: 10.1074/jbc.M200446200. Epub 2002 Jul 1.


PAAD domains are found in diverse proteins of unknown function and are structurally related to a superfamily of protein interaction modules that includes death domains, death effector domains, and Caspase activation and recruitment domains. Using bioinformatics strategies, cDNAs were identified that encode a novel protein of 110 kDa containing a PAAD domain followed by a putative nucleotide-binding (NACHT) domain and several leucine-rich repeat domains. This protein thus resembles Cryopyrin, a protein implicated in hereditary hyperinflammation syndromes, and was termed PAN2 for PAAD and NACHT-containing protein 2. When expressed in HEK293 cells, PAN2 suppressed NF-kappaB induction by the cytokines tumor necrosis factor-alpha (TNFalpha) and interleukin-1beta (IL-1beta), suggesting that this protein operates at a point of convergence in these two cytokine signaling pathways. This PAN2-mediated suppression of NF-kappaB was evident both in reporter gene assays that measured NF-kappaB transcriptional activity and electromobility shift assays that measured NF-kappaB DNA binding activity. PAN2 also suppressed NF-kappaB induction resulting from overexpression of several adapter proteins and protein kinases involved in the TNF or IL-1 receptor signal transduction, including TRAF2, TRAF6, RIP, IRAK2, and NF-kappaB-inducing kinase as well as the IkappaB kinases IKKalpha and IKKbeta. PAN2 also inhibited the cytokine-mediated activation of IKKalpha and IKKbeta as measured by in vitro kinase assays. Furthermore, PAN2 association with IKKalpha was demonstrated by co-immunoprecipitation assays, suggesting a direct effect on the IKK complex. These observations suggest a role for PAN2 in modulating NF-kappaB activity in cells, thus providing the insights into the potential functions of PAAD family proteins and their roles in controlling inflammatory responses.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Cloning, Molecular
  • DNA Primers
  • Electrophoretic Mobility Shift Assay
  • Enzyme Activation
  • Humans
  • I-kappa B Kinase
  • Interleukin-1 / physiology*
  • Molecular Sequence Data
  • NF-kappa B / biosynthesis*
  • Protein-Serine-Threonine Kinases / metabolism
  • Proteins / chemistry
  • Proteins / genetics
  • Proteins / physiology*
  • Repressor Proteins
  • Reverse Transcriptase Polymerase Chain Reaction
  • Tumor Necrosis Factor-alpha / physiology*


  • DNA Primers
  • Interleukin-1
  • NF-kappa B
  • NLRP4 protein, human
  • Proteins
  • Repressor Proteins
  • Tumor Necrosis Factor-alpha
  • Protein-Serine-Threonine Kinases
  • CHUK protein, human
  • I-kappa B Kinase
  • IKBKB protein, human
  • IKBKE protein, human

Associated data

  • GENBANK/AY072792