FIGURE 5.

YopJ activity in S. pombe following oxidative and osmotic stress. A, actively growing cultures of the wild-type (wt) strain transformed with plasmids encoding either GFP-YopJ (672W), GFP-YopJ(C172A) (674W), or the untransformed sty1Δ strain (772W) were exposed to 1 mm H₂O₂ for 30 min. The resulting whole cell extracts were fractionated by SDS-PAGE, and the levels of total and phosphorylated eIF2α were determined by Western analysis. Signals were quantified and normalized to the eIF2α-P/eIF2α ratio observed in the extract derived from the GFP-YopJ(C172A) strain. B, live cells of the same strains were imagined following a 60-min exposure to 1 mm H₂O₂. C, cell elongation assay of the indicated strain (closed boxes, 672W; open boxes, 674W; open circles, 745W, 753W, and 790W) was performed as described in Fig. 3C.