Apoptosis crosstalk between

There is also crosstalk between the two pathways above the mitochondria. The BH3-only protein BID is cleaved by caspase-8 and -10 which yields truncated BID (tBED), the active pro-apoptotic fragment of BID. Thereby, even in cells in which the direct apoptosis pathway which result from death receptor crosslinking is blocked, e.g. by high expression levels ofthex-linked IAP (XIAP), the activity of tBED on mitochondria can result in the activation of caspase-3 because the IAP-imposed block on full caspase-3 activation and caspase-9 activity at the apoptosome is released by Smac/ DIABLO. 

V. Nikoletopoulou, M. Markaki, K. Palikaras, and N. Tavemarakis, Crosstalk between apoptosis, necrosis and autophagy. Biochim. Biophys. Acta., 1833 (2013) 3448-59. 

---