title: A yeast two-hybrid system reconstituting substrate recognition of the von Hippel-Lindau tumor suppressor protein.
abstract: The von Hippel-Lindau tumor suppressor protein (pVHL) is inactivated in the hereditary cancer syndrome von Hippel-Lindau disease and in the majority of sporadic renal carcinomas. pVHL is the substrate-binding subunit of the CBC(VHL) ubiquitin ligase complex that negatively regulates cell growth by promoting the degradation of hypoxia-inducible transcription factor subunits (HIF1/2alpha). Proteomics-based identification of novel pVHL substrates is hampered by their short half-life and low abundancy in mammalian cells. The usefulness of yeast two-hybrid (Y2H) approaches, on the other hand, has been limited by the failure of pVHL to adopt its native structure and by the absence of prolylhydroxylase activity critical for pVHL substrate recognition. Therefore, we modified the Y2H system to faithfully reconstitute the physical interaction between pVHL and its substrates. Our approach relies on the coexpression of pVHL with the cofactors Elongin B and Elongin C and with HIF1/2alpha prolylhydroxylases. In a proof-of-principle Y2H screen, we identified the known substrates HIF1/2alpha and new candidate substrates including diacylglycerol kinase iota, demonstrating that our strategy allows detection of stable interactions between pVHL and otherwise elusive cellular targets. Additional future applications may include structure/function analyses of pVHL-HIF1/2alpha binding and screens for therapeutically relevant compounds that either stabilize or disrupt this interaction.
authors.affiliation: Max Planck Institute of Biochemistry, Department of Molecular Cell Biology, Am Klopferspitz 18, 82152 Martinsried, Germany.
authors.forename: Claudia
authors.initials: C
authors.lastname: Bex
authors.forename: Katja
authors.initials: K
authors.lastname: Knauth
authors.forename: Silvia
authors.initials: S
authors.lastname: Dambacher
authors.forename: Alexander
authors.initials: A
authors.lastname: Buchberger
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D002460:Cell Line; D019852:Diacylglycerol Kinase / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics / Q000378:metabolism; D006899:Mixed Function Oxygenases / Q000378:metabolism; D008969:Molecular Sequence Data; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D020798:Two-Hybrid System Techniques; D051794:Von Hippel-Lindau Tumor Suppressor Protein / Q000235:genetics / Q000378:metabolism*
chemical_list: D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D006899:Mixed Function Oxygenases; D051794:Von Hippel-Lindau Tumor Suppressor Protein; D019852:Diacylglycerol Kinase