Proteomic analysis of the oxidative stress responses in Candida albicans

An efficient oxidative stress response (OSR) is important for the facultative pathogenic yeast Candida albicans to survive within the human host. We used a large scale 2-D protein gel electrophoresis approach to analyze the stress response mechanisms of C. albicans after treatment with hydrogen peroxide and the thiol oxidizing agent, diamide. Quantitation of in vivo protein synthesis after pulse labeling of the proteins with radioactive L-[S-35]-methionine resulted in characteristic proteome signatures for hydrogen peroxide and diamide with significant overlap of 21 up-regulated proteins for both stressors. Among the induced proteins were enzymes with known antioxidant functions like catalase or thioredoxin reductase and a set of oxidoreductases. 2-D gel analysis of mutants in the CAP1 gene revealed that the synthesis of 12 proteins is controlled by the oxidative stress regulator Cap1p. Stressing its importance for the C. albicans OSR, all 12 proteins were also induced after oxidative challenge by hydrogen peroxide or diamide.