FIGURE 3:

Stress sensitivity caused by loss of MIPCs or accumulation of IPCs. (A) Effect of myriocin on complex sphingolipid levels. Cells were cultured overnight in YPD medium at 30°C, diluted (0.3 OD₆₀₀ units/ml) in fresh YPD medium with or without 0.1 µg/ml myriocin, and then incubated for 3 h at 30°C. TLC analysis were performed as described in Figure 1D. The amount of complex sphingolipids (IPCs, MIPCs, and M(IP)₂Cs) in myriocin-untreated wild-type cells was taken as 1. (B) Effect of myriocin on sensitivity to stresses. Cells cultured overnight in YPD medium were spotted onto YPD plates containing 30 mM CaCl₂, 7 mM CuCl₂, 0.4 or 1 M NaCl, 300 mM acetic acid (adjusted to pH 5.5 by the addition of 50 mM MES and MOPS), SDS 0.005%, 5 mM caffeine, or 0.1 µg/ml myriocin, and then incubated for 2 d. YPD plates (pH 3.5) were prepared by the addition of 100 mM Gly-HCl.