Cleavage of BID during cytotoxic drug and UV radiation-induced apoptosis occurs downstream of the point of Bcl-2 action and is catalysed by caspase-3: a potential feedback loop for amplification of apoptosis-associated mitochondrial cytochrome c release.
BID, a pro-apoptotic Bcl-2 family member, promotes cytochrome c release during apoptosis initiated by CD95L or TNF. Activation of caspase-8 in the latter pathways results in cleavage of BID, translocation of activated BID to mitochondria, followed by redistribution of cytochrome c to the cytosol. However, it is unclear whether BID participates in cytochrome c release in other (non-death receptor) cell death pathways. Here, we show that BID is cleaved in response to multiple death-inducing stimuli (staurosporine, UV radiation, cycloheximide, etoposide). However BID cleavage in these contexts was blocked by Bcl-2, suggesting that proteolysis of BID occurred distal to cytochrome c release. Furthermore, addition of cytochrome c to Jurkat post-nuclear extracts triggered breakdown of BID at Asp-59 which was catalysed by caspase-3 rather than caspase-8. We provide evidence that caspase-3 catalysed cleavage of BID represents a feedback loop for the amplification of mitochondrial cytochrome c release during cytotoxic drug and UV radiation-induced apoptosis.
Slee
E A
EA
Molecular Cell Biology Laboratory, Department of Genetics, The Smurfit Institute, Trinity College, Dublin 2, Ireland.
Keogh
S A
SA
Martin
S J
SJ
D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000528:radiation effects; D001224:Aspartic Acid / Q000378:metabolism; D051023:BH3 Interacting Domain Death Agonist Protein; D002352:Carrier Proteins / Q000378:metabolism*; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism*; D002384:Catalysis; D002474:Cell-Free System; D003513:Cycloheximide / Q000494:pharmacology; D003574:Cytochrome c Group / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005047:Etoposide / Q000494:pharmacology; D006801:Humans; D019169:Jurkat Cells; D051379:Mice; D008930:Mitochondria, Liver / Q000187:drug effects / Q000378:metabolism*; D019384:Nucleic Acid Synthesis Inhibitors / Q000494:pharmacology; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D019311:Staurosporine / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D014466:Ultraviolet Rays
D051023:BH3 Interacting Domain Death Agonist Protein; C494814:BID protein, human; C494815:Bid protein, mouse; D002352:Carrier Proteins; D003574:Cytochrome c Group; D004791:Enzyme Inhibitors; D019384:Nucleic Acid Synthesis Inhibitors; D011500:Protein Synthesis Inhibitors; D019253:Proto-Oncogene Proteins c-bcl-2; D001224:Aspartic Acid; D005047:Etoposide; D003513:Cycloheximide; C505407:CASP3 protein, human; C505409:Casp3 protein, mouse; D053148:Caspase 3; D020169:Caspases; D019311:Staurosporine