  Caspases are a family of cysteine proteases that play essential roles during
apoptosis, and we presume some of them may also protect the cell from oxidative
stress. We found that the absence of yeast caspase 1(Yca1)in Saccharomyces
cerevisiae leads to a more intense burst of mitochondrial reactive oxygen
species (ROS) In addition, compared to wild type yeast cells, the ability of
yca1 mutant cells to maintain mitochondrial activity is significantly reduced
after either oxidative stress treatment or aging. During mitochondrial ROS
burst, deletion of the yca1 gene delayed structural damage of a green
fluorescent protein (GFP) reporter bound in the inner mitochondrial membrane.
This work implies that yeast caspase 1 is closely connected to the oxidative
stress response. We speculate that Yca1 can discriminate proteins damaged by
oxidation and accelerate their hydrolysis to attenuate the ROS burst.
