High levels of Cdc42p induce fMAPK pathway activity. (A) Analysis of P∼Kss1p, Cdc42p, and Pgk1p levels in wild-type cells (WT, PC538) grown in YEPGAL (Gal) media for the times indicated. See Fig. 3 F for details. (B)bem4Δ cells (PC3551) were examined as indicated in A. See Fig. 3 F for details. (C) Wild-type cells (WT, PC6810) and the bem4Δ mutant (PC7179) expressing GFP-Cdc42p (Cdc42, PC6454), GFP-Cdc42p^Q61L (Q61L, PC7458) or GFP-Cdc42p^Q61L+TD (Q61L+TD, PC7654) were grown for 6 h in SD-URA media. See Fig. 3 F for details. (D) Microscopic examination of cells described in C. Scale bar, 5 µm. Right: Elongated cells expressed as a percentage for the same strains shown on the left. A cell was considered elongated with >1.40 of length/width ratio. Error bars represent the SD detected from three biological replicates, (n = 3); 200 cells were analyzed in each replicate. Data were analyzed by one-way ANOVA, and the P value (asterisk < 0.01) was calculated using Tukey’s multiple comparison test. Source data are available for this figure: SourceData F5.