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-Structure paper
Title | Structure of the apoptosome: mechanistic insights into activation of an initiator caspase from Drosophila. |
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Journal, issue, pages | Genes Dev, Vol. 29, Issue 3, Page 277-287, Year 2015 |
Publish date | Feb 1, 2015 |
Authors | Yuxuan Pang / Xiao-chen Bai / Chuangye Yan / Qi Hao / Zheqin Chen / Jia-Wei Wang / Sjors H W Scheres / Yigong Shi / |
PubMed Abstract | Apoptosis is executed by a cascade of caspase activation. The autocatalytic activation of an initiator caspase, exemplified by caspase-9 in mammals or its ortholog, Dronc, in fruit flies, is ...Apoptosis is executed by a cascade of caspase activation. The autocatalytic activation of an initiator caspase, exemplified by caspase-9 in mammals or its ortholog, Dronc, in fruit flies, is facilitated by a multimeric adaptor complex known as the apoptosome. The underlying mechanism by which caspase-9 or Dronc is activated by the apoptosome remains unknown. Here we report the electron cryomicroscopic (cryo-EM) structure of the intact apoptosome from Drosophila melanogaster at 4.0 Å resolution. Analysis of the Drosophila apoptosome, which comprises 16 molecules of the Dark protein (Apaf-1 ortholog), reveals molecular determinants that support the assembly of the 2.5-MDa complex. In the absence of dATP or ATP, Dronc zymogen potently induces formation of the Dark apoptosome, within which Dronc is efficiently activated. At 4.1 Å resolution, the cryo-EM structure of the Dark apoptosome bound to the caspase recruitment domain (CARD) of Dronc (Dronc-CARD) reveals two stacked rings of Dronc-CARD that are sandwiched between two octameric rings of the Dark protein. The specific interactions between Dronc-CARD and both the CARD and the WD40 repeats of a nearby Dark protomer are indispensable for Dronc activation. These findings reveal important mechanistic insights into the activation of initiator caspase by the apoptosome. |
External links | Genes Dev / PubMed:25644603 / PubMed Central |
Methods | EM (single particle) |
Resolution | 4.0 - 4.1 Å |
Structure data | |
Chemicals | ChemComp-ADP: ChemComp-DTP: |
Source |
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Keywords | APOPTOSIS / programmed cell death / caspase activation |