Diverse Effects of Mutations in Exon II of the von Hippel-Lindau (VHL) Tumor Suppressor Gene on the Interaction of pVHL with the Cytosolic Chaperonin and pVHL-Dependent Ubiquitin Ligase Activity

• DOI: 10.1128/mcb.22.6.1947-1960.2002
• Publication Date: 2002-07-27T09:56:57Z
• Authors: William J. Hansen; Michael Ohh; Javid Moslehi; Keiichi Kondo; William G. Kaelin; William J. Welch
• Keywords: 0301 basic medicine; Protein Folding; Chaperonins; Macromolecular Substances; Tumor Suppressor Proteins; Elongin; Cell Cycle Proteins; Exons; Cullin Proteins; Hypoxia-Inducible Factor 1, alpha Subunit; Transfection; Ligases; Structure-Activity Relationship; 03 medical and health sciences; Mutation; Mutagenesis, Site-Directed; Tumor Cells, Cultured; Humans; Carcinoma, Renal Cell; Chaperonin Containing TCP-1; Protein Binding; Transcription Factors

We examined the biogenesis of von Hippel-Lindau (VHL) tumor suppressor protein (pVHL) in vitro and vivo. pVHL formed a complex with cytosolic chaperonin containing TCP-1 (CCT or TRiC) en route to assembly elongin B/C subsequent formation VCB-Cul2 ubiquitin ligase. Blocking interaction resulted accumulation within CCT complex. present purified VHL-CCT complexes, when added rabbit reticulocyte lysate, proceeded form VCB VCB-Cul2. Thus, likely functions, at least part, by retaining VHL chains pending availability for final folding and/or assembly. Tumor-associated mutations exon II syndrome had diverse effects upon stability function pVHL-containing complexes. First, mutant lacking entire region encoded did not bind yet could still assemble into complexes B/C-Cul2. Second, number tumor-derived missense decrease binding, most no detectable effect Many mutants, however, were found be defective binding ubiquitination hypoxia-inducible factor 1α (HIF-1α), substrate conclude that selection pressure mutate during tumorigenesis does relate loss but may reflect quantitative qualitative defects HIF pVHL-dependent ligase activity.