title: Role of the NEDD8 modification of Cul2 in the sequential activation of ECV complex.
abstract: ECV is an E3 ubiquitin ligase complex, which is composed of elongins B and C, Rbx1, Cul2, and the substrate-conferring von Hippel-Lindau (VHL) tumor-suppressor protein that targets the catalytic alpha subunit of hypoxia-inducible factor (HIF) for oxygen-dependent ubiquitin-mediated destruction. Mutations in VHL that compromise proper HIFalpha regulation through ECV have been documented in the majority of renal cell carcinomas, underscoring the significance of the VHL-HIF pathway in renal epithelial oncogenesis. Recent evidence has shown that the modification of Cul2 by the ubiquitin-like molecule NEDD8 increases the activity of ECV to ubiquitylate HIFalpha. However, the underlying mechanism responsible for the NEDD8-mediated induction of ECV function is unknown. Here, we demonstrate that oxygen-dependent recognition of HIFalpha by VHL triggers Rbx1-dependent neddylation of Cul2, which preferentially engages the E2 ubiquitin-conjugating enzyme UbcH5a. These events establish a central role for the neddylation of Cul2 in a previously unrecognized, temporally coordinated activation of ECV with the recruitment of its substrate HIFalpha.
authors.affiliation: Department of Laboratory Medicine and Pathobiology, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8.
authors.forename: Roxana I
authors.initials: RI
authors.lastname: Sufan
authors.forename: Michael
authors.initials: M
authors.lastname: Ohh
mesh_terms: D002352:Carrier Proteins / Q000378:metabolism; D020134:Catalytic Domain; D002460:Cell Line; D044842:Cullin Proteins / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D000860:Hypoxia; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism; D033862:Iron-Binding Proteins / Q000378:metabolism; D008954:Models, Biological; D009154:Mutation; D000075687:NEDD8 Protein; D010100:Oxygen / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D044763:Ubiquitin-Conjugating Enzymes / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000737:chemistry*; D014452:Ubiquitins / Q000378:metabolism / Q000502:physiology*
chemical_list: C105153:CUL2 protein, human; D002352:Carrier Proteins; D044842:Cullin Proteins; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D033862:Iron-Binding Proteins; D000075687:NEDD8 Protein; C082860:NEDD8 protein, human; C479529:RBX1 protein, human; D014452:Ubiquitins; C097308:UBE2D1 protein, human; D044763:Ubiquitin-Conjugating Enzymes; D044767:Ubiquitin-Protein Ligases; D010100:Oxygen