title: VHL mutations linked to type 2C von Hippel-Lindau disease cause extensive structural perturbations in pVHL.
abstract: pVHL (von Hippel-Lindau tumor suppressor protein) is the substrate recognition subunit of the CBC(VHL) ubiquitin ligase complex promoting the degradation of hypoxia-inducible factor subunits, HIF-1/2alpha. Mutational inactivation of pVHL causes the hereditary von Hippel-Lindau tumor syndrome, which predisposes affected individuals to hemangioblastomas, renal cell carcinomas, and pheochromocytomas. Whereas the development of hemangioblastomas and renal cell carcinomas has been attributed to impaired HIF-1/2alpha down-regulation by pVHL mutant proteins, the molecular defects underlying the development of pheochromocytomas are still unknown. Here, we present a detailed biochemical analysis of pVHL mutant proteins linked to type 2C (pheochromocytoma only) von Hippel-Lindau disease. Type 2C-associated mutations caused extensive structural perturbations of pVHL, as revealed by the reduced stability, increased proteolytic susceptibility, and dramatically altered NMR spectrum of recombinant, mutant pVHL-ElonginC-ElonginB complexes in vitro. In human cell lines, type 2C-linked mutations destabilized the CBC(VHL) ubiquitin ligase complex and resulted in reduced cellular pVHL levels. Together, our data reveal unexpectedly strong structural defects of type 2C-associated pVHL mutant proteins that are likely to affect both HIF-1/2alpha-related and -unrelated pVHL functions in the pathogenesis of pheochromocytomas.
authors.affiliation: Department of Molecular Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany.
authors.forename: Katja
authors.initials: K
authors.lastname: Knauth
authors.forename: Edward
authors.initials: E
authors.lastname: Cartwright
authors.forename: Stefan
authors.initials: S
authors.lastname: Freund
authors.forename: Mark
authors.initials: M
authors.lastname: Bycroft
authors.forename: Alexander
authors.initials: A
authors.lastname: Buchberger
mesh_terms: D000310:Adrenal Gland Neoplasms / Q000145:classification / Q000235:genetics / Q000503:physiopathology; D000818:Animals; D002460:Cell Line; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics / Q000378:metabolism; D046912:Multiprotein Complexes / Q000378:metabolism; D009154:Mutation; D010673:Pheochromocytoma / Q000145:classification / Q000235:genetics / Q000503:physiopathology; D011485:Protein Binding; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D051794:Von Hippel-Lindau Tumor Suppressor Protein / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D006623:von Hippel-Lindau Disease / Q000145:classification / Q000235:genetics* / Q000503:physiopathology
chemical_list: D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D046912:Multiprotein Complexes; D011994:Recombinant Proteins; D051794:Von Hippel-Lindau Tumor Suppressor Protein