Post-translational modification of Bid has differential effects on its susceptibility to cleavage by caspase 8 or caspase 3.
Bid is instrumental in death receptor-mediated apoptosis where it is cleaved by caspase 8 at aspartate 60 and aspartate 75 to generate truncated Bid (tBID) forms that facilitate release of mitochondrial cytochrome c. Bid is also cleaved at these sites by caspase 3 that is activated downstream of cytochrome c release after diverse apoptotic stimuli. In this context, tBid may amplify the apoptotic process. Bid is phosphorylated in vitro by casein kinases that regulate its cleavage by caspase 8 (Desagher, S., Osen-Sand, A., Montessuit, S., Magnenat, E., Vilbois, F., Hochmann, A., Journot, L. Antonsson, A., and Martinou, J.-C. (2001) Mol. Cell 8, 601-611). Using a Bid decapeptide substrate, we observed that phosphorylation at threonine 59 inhibited cleavage by caspase 8. This was also seen when recombinant Bid (rBid) and Bid isolated from murine kidney were incubated with casein kinase II. However, there were differences in the susceptibility of rBid and isolated Bid to cleavage by caspases 3 and 8. Caspase 8 cleaved rBid to generate two C-terminal products, p15 and p13 tBid, but produced only p15 tBid from isolated Bid. Contrary to rBid, isolated Bid was resistant to cleavage by caspase 3, yet was readily cleaved within the cytosolic milieu. Our data suggest that one or more distinct cellular mechanisms regulate Bid cleavage by caspases 8 and 3 in situ.
Degli Esposti
Mauro
M
Cancer Research UK Cellular and Molecular Pharmacology Group, School of Biological Sciences, University of Manchester, Stopford Bldg., Oxford Road, Manchester M13 9PT, UK.
Ferry
Gilles
G
Masdehors
Peggy
P
Boutin
Jean A
JA
Hickman
John A
JA
Dive
Caroline
C
D000135:Acid Phosphatase / Q000494:pharmacology; D000595:Amino Acid Sequence; D000818:Animals; D051023:BH3 Interacting Domain Death Agonist Protein; D002352:Carrier Proteins / Q000378:metabolism*; D053148:Caspase 3; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases / Q000502:physiology*; D002460:Cell Line; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational
D051023:BH3 Interacting Domain Death Agonist Protein; C494814:BID protein, human; C494815:Bid protein, mouse; D002352:Carrier Proteins; D000135:Acid Phosphatase; C505407:CASP3 protein, human; C505530:CASP8 protein, human; C506433:CASP9 protein, human; C505409:Casp3 protein, mouse; C505526:Casp8 protein, mouse; C506434:Casp9 protein, mouse; D053148:Caspase 3; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases