Download MendeleyStructural and biochemical basis of apoptotic activation by Smac/DIABLO.
Chai, J., Du, C., Wu, J.W., Kyin, S., Wang, X., Shi, Y.(2000) Nature 406: 855-862
- PubMed: 10972280
- DOI: https://doi.org/10.1038/35022514
- Primary Citation of Related Structures:
1FEW - PubMed Abstract:
Apoptosis (programmed cell death), an essential process in the development and homeostasis of metazoans, is carried out by caspases. The mitochondrial protein Smac/DIABLO performs a critical function in apoptosis by eliminating the inhibitory effect of IAPs (inhibitor of apoptosis proteins) on caspases. Here we show that Smac/DIABLO promotes not only the proteolytic activation of procaspase-3 but also the enzymatic activity of mature caspase-3, both of which depend upon its ability to interact physically with IAPs. The crystal structure of Smac/DIABLO at 2.2 A resolution reveals that it homodimerizes through an extensive hydrophobic interface. Missense mutations inactivating this dimeric interface significantly compromise the function of Smac/DIABLO. As in the Drosophila proteins Reaper, Grim and Hid, the amino-terminal amino acids of Smac/DIABLO are indispensable for its function, and a seven-residue peptide derived from the amino terminus promotes procaspase-3 activation in vitro. These results establish an evolutionarily conserved structural and biochemical basis for the activation of apoptosis by Smac/DIABLO.
Organizational Affiliation:
Department of Molecular Biology, Princeton University, New Jersey 08544, USA.
