Old yellow enzyme interferes with Bax-induced NADPH loss and lipid peroxidation in yeast.

The yeast transcriptional response to murine Bax expression was compared with the changes induced by H(2)O(2) treatment via microarray technology. Although most of the Bax-responsive genes were also triggered by H(2)O(2) treatment, OYE3, ICY2, MLS1 and BTN2 were validated to have a Bax-specific transcriptional response not shared with the oxidative stress trigger. In knockout experiments, only deletion of OYE3, coding for yeast Old yellow enzyme, attenuated the rate of Bax-induced growth arrest, cell death and NADPH decrease. Lipid peroxidation was completely absent in DeltaOYE3 expressing Bax. However, the absence of OYE3 sensitized yeast cells to H(2)O(2)-induced cell death, and increased the rate of NADPH decrease and lipid peroxidation. Our results clearly indicate that OYE3 interferes with Bax- and H(2)O(2)-induced lipid peroxidation and cell death in Saccharomyces cerevisiae.