Aven, a novel inhibitor of caspase activation, binds Bcl-xL and Apaf-1.
Bcl-x(L), an antiapoptotic Bcl-2 family member, is postulated to function at multiple stages in the cell death pathway. The possibility that Bcl-x(L) inhibits cell death at a late (postmitochondrial) step in the death pathway is supported by this report of a novel apoptosis inhibitor, Aven, which binds to both Bcl-x(L) and the caspase regulator, Apaf-1. Identified in a yeast two-hybrid screen, Aven is broadly expressed and is conserved in other mammalian species. Only those mutants of Bcl-x(L)that retain their antiapoptotic activity are capable of binding Aven. Aven interferes with the ability of Apaf-1 to self-associate, suggesting that Aven impairs Apaf-1-mediated activation of caspases. Consistent with this idea, Aven inhibited the proteolytic activation of caspases in a cell-free extract and suppressed apoptosis induced by Apaf-1 plus caspase-9. Thus, Aven represents a new class of cell death regulator.
Pubmed ID: 10949025 RIS Download
Adaptor Proteins, Signal Transducing | Amino Acid Sequence | Animals | Apoptosis | Apoptosis Regulatory Proteins | Apoptotic Protease-Activating Factor 1 | Carrier Proteins | Caspase 9 | Caspases | Cell Line | Dimerization | Enzyme Activation | Humans | Membrane Proteins | Mice | Molecular Sequence Data | Mutation | Protein Binding | Protein Structure, Quaternary | Proteins | Proto-Oncogene Proteins c-bcl-2 | RNA, Messenger | Tissue Distribution | Transfection | bcl-X Protein