P7
Chris Meisinger / Burkhard Bechinger (Strasbourg)
Bax induced protein export across the mitochondrial outer membrane
Mitochondria play a central part in the initiation of programmed cell death. Pro-apoptotic proteins of the Bcl-2 family (e.g. Bax) induce the release of the intermembrane space protein Cytochrome c, which then lead to the activation of a caspase cascade in the cytosol following execution of cell death. Although the budding yeast Saccharomyces cerevisiae lacks typical members of the Bcl-2 family, it is well established that yeast shows typical features of programmed cell death, such like morphological changes, externalization of phosphatidylserine, fragmentation of chromatin and the release of Cytochrome c from the intermembrane space into the cytosol upon induction with Bax. This response can be antagonized by coexpression of the anti-apoptotic protein Bcl-2. Yeast is therefore an ideal organism to study this evolutionarily conserved mechanism. We have established an yeast in vitro assay for the release of mitochondrial intermembrane space proteins using purified recombinant human Bax protein and want to analyze by which mechanism these proteins are exported across the outer mitochondrial membrane.