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A complex containing βTrCP recruits Ccd34 to catalyse ubiquitination of IκBα
Author(s) -
Vuillard Laurent,
Nicholson John,
Hay Ronald T
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)00895-9
Subject(s) - ubiquitin , phosphorylation , skp1 , f box protein , serine , chemistry , ubiquitin ligase , lysine , biochemistry , transcription factor , deubiquitinating enzyme , peptide , microbiology and biotechnology , biology , amino acid , gene
Activation of transcription factor NF‐κB is accomplished by degradation of its inhibitor IκBα. Signal induced phosphorylation of IκBα on serine 32 and 36 targets the protein for ubiquitination on lysine 21 and 22. Here we use a phosphorylated peptide substrate representing residues 20–43 of IκBα to investigate requirements for ubiquitination of IκBα. Phosphorylation dependent polyubiquitination is carried out by a multiprotein complex containing βTrCP, Skp1 and Cdc53 (Cul1). In the presence of ubiquitin activating enzyme and the protein complex containing βTrCP, polyubiquitination of IκBα peptide was dependent on the presence of Cdc34, while Ubc5 only stimulated mono‐ and di‐ubiquitination.