Identification of a novel 300-kDa factor termed IkappaB alphaE3-F1 that is required for ubiquitinylation of IkappaB alpha

FEBS Lett. 1999 Sep 24;458(3):343-8. doi: 10.1016/s0014-5793(99)01173-4.

Abstract

Destruction of IkappaB by ubiquitinylation is required for signal-dependent activation of NF-kappaB. The IkappaB alpha ubiquitin-ligase activity associated with phosphorylated IkappaB alpha (pIkappaB alpha) in HeLa cells was almost completely lost by washing under stringent conditions including 1 M NaCl; nevertheless, an SCF(betaTrCP) complex containing Skp1, Cullin-1, and F-box/WD40 protein betaTrCP was still bound to pIkappaB alpha, suggesting the existence of a putative factor that is loosely associated with pIkappaB alpha and may collaborate with SCF(betaTrCP). The factor was named IkappaB alphaE3-F1 and was partially purified from HeLa cells. Gel filtration analysis revealed that IkappaB alphaE3-F1 has an apparent molecular mass of approximately 300 kDa.

MeSH terms

  • Blotting, Western
  • Cell Cycle Proteins / metabolism
  • Cullin Proteins*
  • DNA-Binding Proteins / chemistry*
  • DNA-Binding Proteins / metabolism*
  • HeLa Cells
  • Humans
  • I-kappa B Proteins*
  • NF-KappaB Inhibitor alpha
  • Neoplasm Proteins / chemistry
  • Peptide Synthases / metabolism
  • Phosphorylation
  • Precipitin Tests
  • Protein Binding
  • S-Phase Kinase-Associated Proteins
  • SKP Cullin F-Box Protein Ligases
  • Salts / pharmacology
  • Tumor Necrosis Factor-alpha / pharmacology
  • Ubiquitins / metabolism*

Substances

  • Cell Cycle Proteins
  • Cullin 1
  • Cullin Proteins
  • DNA-Binding Proteins
  • I-kappa B Proteins
  • NFKBIA protein, human
  • Neoplasm Proteins
  • S-Phase Kinase-Associated Proteins
  • Salts
  • Tumor Necrosis Factor-alpha
  • Ubiquitins
  • NF-KappaB Inhibitor alpha
  • SKP Cullin F-Box Protein Ligases
  • Peptide Synthases