Crystal structure of full-length Apaf-1: how the death signal is relayed in the mitochondrial pathway of apoptosis.Reubold, T.F., Wohlgemuth, S., Eschenburg, S.
(2011) Structure 19: 1074-1083
- PubMed: 21827944
- DOI: https://doi.org/10.1016/j.str.2011.05.013
- Primary Citation of Related Structures:
- PubMed Abstract:
The apoptotic protease-activating factor 1 (Apaf-1) relays the death signal in the mitochondrial pathway of apoptosis. Apaf-1 oligomerizes on binding of mitochondrially released cytochrome c into the heptameric apoptosome complex to ignite the downstream cascade of caspases. Here, we present the 3.0 Å crystal structure of full-length murine Apaf-1 in the absence of cytochrome c. The structure shows how the mammalian death switch is kept in its "off" position. By comparing the off state with a recent cryo-electron microscopy derived model of Apaf-1 in its apoptosomal conformation, we depict the molecular events that transform Apaf-1 from autoinhibited monomer to a building block of the caspase-activating apoptosome. Moreover, we have solved the crystal structure of the R265S mutant of full-length murine Apaf-1 in the absence of cytochrome c to 3.55 Å resolution and we show that proper function of Apaf-1 relies on R265 in the vicinity of the bound nucleotide.
Insitute for Biophysical Chemistry, Hannover Medical School, OE 4350, D-30625, Hannover, Germany.