Identification of a novel 300-kDa factor termed IkappaB alphaE3-F1 that is required for ubiquitinylation of IkappaB alpha.
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.
Suzuki
H
H
Institute for Drug Discovery Research, Yamanouchi Pharmaceutical Co., Ltd., Ibaraki, Japan.
Kobayashi
M
M
Takeuchi
M
M
Furuichi
K
K
Chiba
T
T
Tanaka
K
K
D015153:Blotting, Western; D018797:Cell Cycle Proteins / Q000378:metabolism; D044842:Cullin Proteins; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D020672:I-kappa B Proteins; D000072000:NF-KappaB Inhibitor alpha; D009363:Neoplasm Proteins / Q000737:chemistry; D010453:Peptide Synthases / Q000378:metabolism; D010766:Phosphorylation; D011233:Precipitin Tests; D011485:Protein Binding; D044786:S-Phase Kinase-Associated Proteins; D044843:SKP Cullin F-Box Protein Ligases; D012492:Salts / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D014452:Ubiquitins / Q000378:metabolism*
D018797:Cell Cycle Proteins; C100318:Cullin 1; D044842:Cullin Proteins; D004268:DNA-Binding Proteins; D020672:I-kappa B Proteins; C000606204:NFKBIA protein, human; D009363:Neoplasm Proteins; D044786:S-Phase Kinase-Associated Proteins; D012492:Salts; D014409:Tumor Necrosis Factor-alpha; D014452:Ubiquitins; D000072000:NF-KappaB Inhibitor alpha; D044843:SKP Cullin F-Box Protein Ligases; D010453:Peptide Synthases