title: A Bax/Bak-independent mitochondrial death pathway triggered by Drosophila Grim GH3 domain in mammalian cells.
abstract: Grim encodes a protein required for programmed cell death in Drosophila, whose proapoptotic activity is conserved in mammalian cells. Two proapoptotic domains are relevant for Grim killing function; the N-terminal region, which induces apoptosis by disrupting inhibitor of apoptosis protein (IAP) blockage of caspase activity, and the internal GH3 domain, which triggers a mitochondrial pathway. We explored the role of these two domains in heterologous killing of mammalian cells by Grim. The GH3 domain is essential for Grim proapoptotic activity in mouse cells, whereas the N-terminal domain is dispensable. The GH3 domain is required and sufficient for Grim targeting to mitochondria and for cytochrome c release in a caspase- and N-terminal-independent, IAP-insensitive manner. These Grim GH3 activities do not require Bax or Bak function, revealing GH3 activity as the first proapoptotic stimulus able to trigger the mitochondrial death pathway in mammalian cells in the absence of multidomain proapoptotic Bcl-2 proteins.
authors.affiliation: Departamento de Inmunologiía y Oncología, Centro Nacional de Biotecnología/Consejo Superior de Investigaciones Cientiíficas, Universidad Autónoma de Madrid Campus de Cantoblanco, E-28049 Madrid, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: Claveria
authors.forename: Carlos
authors.initials: C
authors.lastname: Martinez-A
authors.forename: Miguel
authors.initials: M
authors.lastname: Torres
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis; D051023:BH3 Interacting Domain Death Agonist Protein; D002352:Carrier Proteins / Q000378:metabolism; D016923:Cell Death; D002470:Cell Survival; D004330:Drosophila / Q000378:metabolism*; D005347:Fibroblasts / Q000378:metabolism; D005822:Genetic Vectors; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D008856:Microscopy, Fluorescence; D008928:Mitochondria / Q000378:metabolism / Q000473:pathology*; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D041681:NIH 3T3 Cells; D011233:Precipitin Tests; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2; D017386:Sequence Homology, Amino Acid; D050998:bcl-2 Homologous Antagonist-Killer Protein; D051028:bcl-2-Associated X Protein
chemical_list: D051023:BH3 Interacting Domain Death Agonist Protein; C494773:Bak1 protein, mouse; C494827:Bax protein, mouse; C494815:Bid protein, mouse; D002352:Carrier Proteins; D008565:Membrane Proteins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D050998:bcl-2 Homologous Antagonist-Killer Protein; D051028:bcl-2-Associated X Protein