FIGURE 4.

Aggravation of DTT-induced aggregation of ER proteins by PMME. (A,B) The KMY1516 strain (ire1Δ) carrying the IRE1 plasmid pRS313-IRE1 (wild-type (WT) or the indicated mutants) was grown in SD medium and treated with 10 mM PMME and/or 1 mM DTT or not treated as shown in Figure 2C. The cells were then checked for HAC1-mRNA splicing. (C) Wild-type yeast BY4741 cells (WT cells) were grown in SD medium and treated with 10 mM PMME and/or 1 mM DTT or not treated as shown in Figure 2C. The cells were then subjected to the BiP sedimentation assay. The panels represent anti-BiP Western-blotting images of the total cell lysates (equivalent to 0.025 OD₆₀₀ cells) and the pellet samples (equivalent to 0.25 OD₆₀₀ cells). (D) BY4741 cells (WT cells) carrying the eroGFP expression plasmid pPM28 were grown in SD medium and treated with 10 mM PMME and/or 1 mM DTT or not treated as shown in Figure 2C. The cells were then observed under a fluorescence microscope. The eroGFP values are normalized against that of non-treated cells, which is set at 1.00. ns, not significant (p > 0.05).