1. Direct activation of caspase 8 by the proapoptotic E2 protein of HPV18 independent of adaptor proteins
- Author
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Caroline Demeret, Françoise Thierry, Expression Génétique et Maladies (EGM), Institut Pasteur [Paris]-Centre National de la Recherche Scientifique (CNRS), This work was supported by the Pasteur Institute, CNRS, Association pour la Recherche sur le Cancer (ARC) and La Ligue Contre le Cancer., We thank Moshe Yaniv and Jonathan Weitzman for critical reading of the paper. We thank Richard Siegel, Marcus Peter, Visha Dixit and Richard Kitsis for providing expression plasmids., and Institut Pasteur [Paris] (IP)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Cytoplasm ,Death fold ,Fas-Associated Death Domain Protein ,Caspase 2 ,Caspase 3 ,Apoptosis ,Biology ,Caspase 8 ,Protein Structure, Secondary ,Cell Line ,03 medical and health sciences ,Viral Proteins ,Humans ,FADD ,Molecular Biology ,030304 developmental biology ,0303 health sciences ,NLRP1 ,030302 biochemistry & molecular biology ,Cell Biology ,Oncogene Proteins, Viral ,Cell biology ,Enzyme Activation ,Death-inducing signaling complex ,[SDV.MP.VIR]Life Sciences [q-bio]/Microbiology and Parasitology/Virology ,biology.protein ,Caspase 10 - Abstract
International audience; The self-activation of initiator caspases is dependent on their oligomerization driven by interaction with the death fold domains (DFD) of adaptor proteins. Here, we show that the E2 protein of human papillomavirus type 18 triggers apoptosis by assembling cytoplasmic filaments together with caspase 8, in which its efficient self-activation occurs. The E2 protein binds directly to the death effector domains (DED) of caspase 8 through non-DFD interaction. This interaction is independent of FADD, but it can cooperate with FADD homotypic binding to caspase 8 to induce its oligomerization; hence cell death, while it is antagonized by competitive binding of MC159 FLICE inhibitory protein. The amino-terminal domain of E2 contains a 27 amino-acid a-helix, which is necessary and sufficient to induce caspase oligomerization and cell death. Our results provide evidence for adaptor-independent oligomerization of caspase 8, mediated by non-DFD direct interactions with the HPV18 E2 protein, thus deciphering a new pathway for caspase 8 activation.
- Published
- 2008