Role of adapter function in oncoprotein-mediated activation of NF-kappaB. Human T-cell leukemia virus type I Tax interacts directly with IkappaB kinase gamma

J Biol Chem. 1999 Jun 18;274(25):17402-5. doi: 10.1074/jbc.274.25.17402.


Mechanisms by which the human T-cell leukemia virus type I Tax oncoprotein activates NF-kappaB remain incompletely understood. Although others have described an interaction between Tax and a holo-IkappaB kinase (IKK) complex, the exact details of protein-protein contact are not fully defined. Here we show that Tax binds to neither IKK-alpha nor IKK-beta but instead complexes directly with IKK-gamma, a newly characterized component of the IKK complex. This direct interaction with IKK-gamma correlates with Tax-induced IkappaB-alpha phosphorylation and NF-kappaB activation. Thus, our findings establish IKK-gamma as a key molecule for adapting an oncoprotein-specific signaling to IKK-alpha and IKK-beta.

MeSH terms

  • DNA-Binding Proteins / metabolism
  • Gene Products, tax / metabolism*
  • HeLa Cells
  • Humans
  • I-kappa B Kinase
  • I-kappa B Proteins*
  • NF-KappaB Inhibitor alpha
  • NF-kappa B / metabolism*
  • Oncogene Proteins / metabolism
  • Phosphorylation
  • Protein Binding
  • Protein Serine-Threonine Kinases / metabolism*
  • Signal Transduction
  • Transcriptional Activation
  • Transfection


  • DNA-Binding Proteins
  • Gene Products, tax
  • I-kappa B Proteins
  • NF-kappa B
  • NFKBIA protein, human
  • Oncogene Proteins
  • NF-KappaB Inhibitor alpha
  • Protein Serine-Threonine Kinases
  • CHUK protein, human
  • I-kappa B Kinase
  • IKBKB protein, human
  • IKBKE protein, human

Associated data

  • GENBANK/AF091453