FIGURE 7.

Assaying YpkA activity in S. pombe co-expressing YpkA and YopJ. A, actively growing cultures of strains possessing an integrated gfp-ypkA gene and either plasmid-encoded gfp-yopJ or gfp-yopJ(C172A) (755W and 759W, respectively) were shifted to GFP-YpkA/GFP-YopJ-expressing conditions. Cells were then periodically removed from the culture, mixed with SDS, and examined microscopically. Shown are images of unfixed intact and detergent-lysed cells after 16 h in expressing conditions. Representative lysed cells (ghosts) are indicated by arrows. B, length measurements of unfixed cells (boxes, 755W; circles, 759W) were made and are plotted either as intact (filled symbols) or lysed (open symbols) cells (*, p < 0.001; not significant (ns), p = 0.70 using a two-sample test to compare proportions in two independent samples). C, drawn from the data shown in B, cells of the GFP-YpkA/GFP-YopJ and GFP-YpkA/GFP-YopJ(C172A) cultures were assigned to either a short or long bin depending on whether their length fell below or above the population median for each culture (solid gray or black bars, respectively). The stippled bars represent the distribution of the detergent-sensitive cells (ghosts) between the short and long cell length bins.