Analysis of Phospholipid Profiles of Different Yeast Mutants That Have Altered Transcription Factors by MALDI FTMS

by Batoy, S. Marricor Andresa; Borgmann, Sabine; Flick, Karin; Jones, Jeffrey J.; Kaiser, Peter; Wilkins, Charles L.

The sulfur amino acid metab. in Saccharomyces cerevisiae is dependent on the transcriptional activator Met4. The function of Met4 requires different combinations of other auxiliary transcription factors. These co-factors include Cbf1, Met28, Met31 and Met32. A study done by Yen et al. relates these co-factors to the organism's response to cadmium stress. To verify the results of their study, phospholipid profiles of the wild type and mutant yeast cells related to the Met4 complex were analyzed. Wild type, cbf1, met28 ?, met32 ?, met31 ? met32 ? mutants were grown in YEPD medium at 30°C. Cells were harvested by filtration, washed in water and lysed in isopropanol. For MALDI FTMS, a satd. soln. of 2,5-dihydroxybenzoic acid in 70% methanol was used as matrix. When histogram plots were made with wild type against cbf1, met28 ?, and met31 ?met32 ? mutants, it is obsd. that there are some distinct phospholipid changes in cbf1 and met31 ?met32 ?mutants. These phospholipid changes are reflected in their phosphatidic acid and phosphatidylcholine contents. However, no distinct phospholipid changes are obsd. for met28 ? mutants. These results reflect the role of these co-factors in their cellular response to cadmium stress as reported by Yen et al. that Cbf1 and Met31/Met32 are transcriptional activators required for cadmium stress but not Met28.