Caspase-2-induced apoptosis requires bid cleavage: a physiological role for bid in heat shock-induced death.
The mechanisms through which Caspase-2 leads to cell death are controversial. Here we show, using a combination of cell-free and cell culture-based approaches, that cleavage of the Bcl-2-family protein Bid is required for the induction of apoptosis by Caspase-2. Caspase-2 promoted cytochrome c release from mitochondria in the presence of cytosol from wild-type, but not Bid-deficient, mouse embryonic fibroblasts (MEFs). Recombinant wild-type Bid, but not a noncleavable mutant (D59E), restored cytochrome c release. Similarly, Bid-null MEFs were relatively resistant to apoptosis triggered by active Caspase-2, and apoptosis was restored in Bid-null cells by the expression of wild-type, but not D59E, Bid. Finally, Bid-null MEFs were substantially more resistant to apoptosis induced by heat shock, which has been shown to be dependent on apical activation of Caspase-2. The data are consistent with a model in which Caspase-2 induces apoptosis via cleavage of Bid at D59 and the subsequent engagement of the mitochondrial (intrinsic) pathway.
Bonzon
Christine
C
Department of Molecular Immunology, La Jolla Institute for Allergy and Immunology, San Diego, CA 92121, USA.
Bouchier-Hayes
Lisa
L
Pagliari
Lisa J
LJ
Green
Douglas R
DR
Newmeyer
Donald D
DD
D000818:Animals; D017209:Apoptosis; D051023:BH3 Interacting Domain Death Agonist Protein / Q000235:genetics / Q000378:metabolism*; D053143:Caspase 2; D020169:Caspases / Q000378:metabolism*; D002478:Cells, Cultured; D045304:Cytochromes c / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D004622:Embryo, Mammalian / Q000166:cytology; D004789:Enzyme Activation; D005347:Fibroblasts / Q000378:metabolism; D006358:Hot Temperature; D051379:Mice; D008928:Mitochondria / Q000378:metabolism; D009154:Mutation
D051023:BH3 Interacting Domain Death Agonist Protein; C494815:Bid protein, mouse; D045304:Cytochromes c; D053143:Caspase 2; D020169:Caspases