title: A complex containing betaTrCP recruits Cdc34 to catalyse ubiquitination of IkappaBalpha.
abstract: Activation of transcription factor NF-kappaB is accomplished by degradation of its inhibitor IkappaBalpha. Signal induced phosphorylation of IkappaBalpha 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 IkappaBalpha to investigate requirements for ubiquitination of IkappaBalpha. Phosphorylation dependent polyubiquitination is carried out by a multiprotein complex containing betaTrCP, Skp1 and Cdc53 (Cull). In the presence of ubiquitin activating enzyme and the protein complex containing betaTrCP, polyubiquitination of IkappaBalpha peptide was dependent on the presence of Cdc34, while Ubc5 only stimulated mono- and di-ubiquitination.
authors.affiliation: School of Biomedical Science, University of St. Andrews, Fife, UK.
authors.forename: L
authors.initials: L
authors.lastname: Vuillard
authors.forename: J
authors.initials: J
authors.lastname: Nicholson
authors.forename: R T
authors.initials: RT
authors.lastname: Hay
mesh_terms: D000595:Amino Acid Sequence; D064173:Anaphase-Promoting Complex-Cyclosome; D000818:Animals; D019556:COS Cells; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D020672:I-kappa B Proteins; D008025:Ligases / Q000378:metabolism*; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000378:metabolism; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010453:Peptide Synthases / Q000737:chemistry / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D044843:SKP Cullin F-Box Protein Ligases; D044763:Ubiquitin-Conjugating Enzymes; D043743:Ubiquitin-Protein Ligase Complexes; D044767:Ubiquitin-Protein Ligases; D014452:Ubiquitins / Q000378:metabolism; D044844:beta-Transducin Repeat-Containing Proteins
chemical_list: C471644:BTRC protein, human; D004268:DNA-Binding Proteins; D020672:I-kappa B Proteins; D046911:Macromolecular Substances; D046912:Multiprotein Complexes; D016328:NF-kappa B; C000606204:NFKBIA protein, human; D010446:Peptide Fragments; D011994:Recombinant Proteins; D014452:Ubiquitins; D044844:beta-Transducin Repeat-Containing Proteins; D000072000:NF-KappaB Inhibitor alpha; C577447:CDC34 protein, human; D044763:Ubiquitin-Conjugating Enzymes; D043743:Ubiquitin-Protein Ligase Complexes; D064173:Anaphase-Promoting Complex-Cyclosome; D044843:SKP Cullin F-Box Protein Ligases; D044767:Ubiquitin-Protein Ligases; D019204:GTP-Binding Proteins; D008025:Ligases; D010453:Peptide Synthases