title: Structure of the E6/E6AP/p53 complex required for HPV-mediated degradation of p53.
abstract: The p53 pro-apoptotic tumour suppressor is mutated or functionally altered in most cancers. In epithelial tumours induced by 'high-risk' mucosal human papilloma viruses, including human cervical carcinoma and a growing number of head-and-neck cancers, p53 is degraded by the viral oncoprotein E6 (ref. 2). In this process, E6 binds to a short leucine (L)-rich LxxLL consensus sequence within the cellular ubiquitin ligase E6AP. Subsequently, the E6/E6AP heterodimer recruits and degrades p53 (ref. 4). Neither E6 nor E6AP are separately able to recruit p53 (refs 3, 5), and the precise mode of assembly of E6, E6AP and p53 is unknown. Here we solve the crystal structure of a ternary complex comprising full-length human papilloma virus type 16 (HPV-16) E6, the LxxLL motif of E6AP and the core domain of p53. The LxxLL motif of E6AP renders the conformation of E6 competent for interaction with p53 by structuring a p53-binding cleft on E6. Mutagenesis of critical positions at the E6-p53 interface disrupts p53 degradation. The E6-binding site of p53 is distal from previously described DNA- and protein-binding surfaces of the core domain. This suggests that, in principle, E6 may avoid competition with cellular factors by targeting both free and bound p53 molecules. The E6/E6AP/p53 complex represents a prototype of viral hijacking of both the ubiquitin-mediated protein degradation pathway and the p53 tumour suppressor pathway. The present structure provides a framework for the design of inhibitory therapeutic strategies against oncogenesis mediated by human papilloma virus.
authors.affiliation: Equipe labellisée Ligue, Biotechnologie et signalisation cellulaire UMR 7242, Ecole Superieure de Biotechnologie de Strasbourg, Boulevard Sébastien Brant, BP 10413, F-67412 Illkirch, France.
authors.forename: Denise
authors.initials: D
authors.lastname: Martinez-Zapien
authors.affiliation: Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC)/INSERM U964/CNRS UMR 7104/Université de Strasbourg, 1 rue Laurent Fries, BP 10142, F-67404 Illkirch, France.
authors.forename: Francesc Xavier
authors.initials: FX
authors.lastname: Ruiz
authors.affiliation: Equipe labellisée Ligue, Biotechnologie et signalisation cellulaire UMR 7242, Ecole Superieure de Biotechnologie de Strasbourg, Boulevard Sébastien Brant, BP 10413, F-67412 Illkirch, France.
authors.forename: Juline
authors.initials: J
authors.lastname: Poirson
authors.affiliation: Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC)/INSERM U964/CNRS UMR 7104/Université de Strasbourg, 1 rue Laurent Fries, BP 10142, F-67404 Illkirch, France.
authors.forename: André
authors.initials: A
authors.lastname: Mitschler
authors.affiliation: Equipe labellisée Ligue, Biotechnologie et signalisation cellulaire UMR 7242, Ecole Superieure de Biotechnologie de Strasbourg, Boulevard Sébastien Brant, BP 10413, F-67412 Illkirch, France.
authors.forename: Juan
authors.initials: J
authors.lastname: Ramirez
authors.affiliation: Equipe labellisée Ligue, Biotechnologie et signalisation cellulaire UMR 7242, Ecole Superieure de Biotechnologie de Strasbourg, Boulevard Sébastien Brant, BP 10413, F-67412 Illkirch, France.
authors.forename: Anne
authors.initials: A
authors.lastname: Forster
authors.affiliation: Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC)/INSERM U964/CNRS UMR 7104/Université de Strasbourg, 1 rue Laurent Fries, BP 10142, F-67404 Illkirch, France.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Cousido-Siah
authors.affiliation: Equipe labellisée Ligue, Biotechnologie et signalisation cellulaire UMR 7242, Ecole Superieure de Biotechnologie de Strasbourg, Boulevard Sébastien Brant, BP 10413, F-67412 Illkirch, France.
authors.forename: Murielle
authors.initials: M
authors.lastname: Masson
authors.affiliation: Department of Pathology, University of Virginia, PO Box 800904, Charlottesville, Virginia 22908-0904, USA.
authors.forename: Scott
authors.initials: S
authors.lastname: Vande Pol
authors.affiliation: Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC)/INSERM U964/CNRS UMR 7104/Université de Strasbourg, 1 rue Laurent Fries, BP 10142, F-67404 Illkirch, France.
authors.forename: Alberto
authors.initials: A
authors.lastname: Podjarny
authors.affiliation: Equipe labellisée Ligue, Biotechnologie et signalisation cellulaire UMR 7242, Ecole Superieure de Biotechnologie de Strasbourg, Boulevard Sébastien Brant, BP 10413, F-67412 Illkirch, France.
authors.forename: Gilles
authors.initials: G
authors.lastname: Travé
authors.affiliation: Equipe labellisée Ligue, Biotechnologie et signalisation cellulaire UMR 7242, Ecole Superieure de Biotechnologie de Strasbourg, Boulevard Sébastien Brant, BP 10413, F-67412 Illkirch, France.
authors.forename: Katia
authors.initials: K
authors.lastname: Zanier
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001665:Binding Sites; D018360:Crystallography, X-Ray; D052162:Human papillomavirus 16 / Q000737:chemistry / Q000378:metabolism* / Q000472:pathogenicity; D006801:Humans; D008954:Models, Biological; D008958:Models, Molecular; D008969:Molecular Sequence Data; D050505:Mutant Proteins / Q000737:chemistry / Q000378:metabolism; D009856:Oncogene Proteins, Viral / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D059748:Proteolysis; D012097:Repressor Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases / Q000737:chemistry*
chemical_list: C068651:E6 protein, Human papillomavirus type 16; D050505:Mutant Proteins; D009856:Oncogene Proteins, Viral; D012097:Repressor Proteins; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; C471639:UBE3A protein, human; D044767:Ubiquitin-Protein Ligases