1. Volume 104, Issue 6, Pages 805-808 (March 2001)
Cell Death Inhibition 
Lakshmi Goyal 
Cell 
Volume 104, Issue 6, Pages (March 2001)
DOI: /S (01)

2. Figure 1 Mechanisms of Caspase Inhibition by IAPs
(A) As revealed by the structures published earlier this month in Cell (Chai et al., 2001; Huang et al., 2001; Riedl et al., 2001), the linker region N-terminal to the BIR2 domain of XIAP is a major structural determinant in binding to the active form of caspase-3 and -7. This complex may be destabilized by the interaction of Smac/DIABLO with BIR2 due to a conformation change. Release of IAP complexed with Smac/DIABLO would relieve the inhibition on the caspase and the active caspase is then free to induce cell death. (B) Caspase-9 inhibition by the BIR3 domain of XIAP requires the initial processing of the pro enzyme to expose the IAP binding motif at the N terminus of the small subunit (Srinivasula et al., 2001). Once exposed BIR3 can bind to the IAP binding motif of caspase-9 and hinder the entry of substrate to the active site of the enzyme. Smac/DIABLO competes with cleaved caspase-9 for binding to BIR3 and the binding partner then determines if the cell undergoes apoptosis
Cell  , DOI: ( /S (01) )