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Identification of a novel 300‐kDa factor termed IκBαE3‐F1 that is required for ubiquitinylation of IκBα
Author(s) -
Suzuki Hiroshi,
Kobayashi Masato,
Takeuchi Masahiro,
Furuichi Kiyoshi,
Chiba Tomoki,
Tanaka Keiji
Publication year - 1999
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(99)01173-4
Subject(s) - ubiquitin ligase , hela , ubiquitin , cullin , microbiology and biotechnology , alpha (finance) , ubiquitin protein ligases , skp1 , biology , phosphorylation , chemistry , biochemistry , in vitro , gene , medicine , construct validity , nursing , patient satisfaction
Destruction of IκB by ubiquitinylation is required for signal‐dependent activation of NF‐κB. The IκBα ubiquitin‐ligase activity associated with phosphorylated IκBα (pIκBα) in HeLa cells was almost completely lost by washing under stringent conditions including 1 M NaCl; nevertheless, an SCF βTrCP complex containing Skp1, Cullin‐1, and F‐box/WD40 protein βTrCP was still bound to pIκBα, suggesting the existence of a putative factor that is loosely associated with pIκBα and may collaborate with SCF βTrCP . The factor was named IκBαE3‐F1 and was partially purified from HeLa cells. Gel filtration analysis revealed that IκBαE3‐F1 has an apparent molecular mass of approximately 300 kDa.