title: Solution structure analysis of the HPV16 E6 oncoprotein reveals a self-association mechanism required for E6-mediated degradation of p53.
abstract: The viral oncoprotein E6 is an essential factor for cervical cancers induced by "high-risk" mucosal HPV. Among other oncogenic activities, E6 recruits the ubiquitin ligase E6AP to promote the ubiquitination and subsequent proteasomal degradation of p53. E6 is prone to self-association, which long precluded its structural analysis. Here we found that E6 specifically dimerizes through its N-terminal domain and that disruption of the dimer interface strongly increases E6 solubility. This allowed us to raise structural data covering the entire HPV16 E6 protein, including the high-resolution NMR structures of the two zinc-binding domains of E6 and a robust data-driven model structure of the N-terminal domain homodimer. Interestingly, homodimer interface mutations that disrupt E6 self-association also inactivate E6-mediated p53 degradation. These data suggest that E6 needs to self-associate via its N-terminal domain to promote the polyubiquitination of p53 by E6AP.
authors.affiliation: Institut de Recherche de l'Ecole de Biotechnologie de Strasbourg (IREBS), Boulevard Sébastien Brant, BP 10413, 67412 Illkirch, France. zanier@unistra.fr
authors.forename: Katia
authors.initials: K
authors.lastname: Zanier
authors.forename: Abdellahi
authors.initials: A
authors.lastname: ould M'hamed ould Sidi
authors.forename: Charlotte
authors.initials: C
authors.lastname: Boulade-Ladame
authors.forename: Vladimir
authors.initials: V
authors.lastname: Rybin
authors.forename: Anne
authors.initials: A
authors.lastname: Chappelle
authors.forename: Andrew
authors.initials: A
authors.lastname: Atkinson
authors.forename: Bruno
authors.initials: B
authors.lastname: Kieffer
authors.forename: Gilles
authors.initials: G
authors.lastname: Travé
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D004926:Escherichia coli; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D019906:Nuclear Magnetic Resonance, Biomolecular; D009856:Oncogene Proteins, Viral / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D011485:Protein Binding; D055503:Protein Multimerization; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D025801:Ubiquitin / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D054875:Ubiquitination
chemical_list: C068651:E6 protein, Human papillomavirus type 16; D009856:Oncogene Proteins, Viral; D011994:Recombinant Proteins; D012097:Repressor Proteins; D016159:Tumor Suppressor Protein p53; D025801:Ubiquitin; C471639:UBE3A protein, human; D044767:Ubiquitin-Protein Ligases; D046988:Proteasome Endopeptidase Complex