Figure 2. Pkc1 enables basal tolerance to ergosterol biosynthesis inhibitors via the MAPK cascade in Saccharomyces cerevisiae.

(A) Drug tolerance of a wild-type (WT) strain (BY4741), a derivative (pkc1-ts) with a temperature sensitive PKC1 allele, and derivatives with deletions of BCK1 and SLT2 are compared in MIC assays. Assays were performed in synthetic defined (SD) medium at 35°C. Data was analyzed after 48 hours as in Figure 1A. The minimum drug concentration that inhibits growth by 80% relative to the drug-free growth control (MIC₈₀) is indicated for each strain. (B) Genetic compromise of Pkc1 creates a fungicidal combination with ergosterol biosynthesis inhibitors. MIC assays with two-fold dilutions of fluconazole (FL), fenpropimorph (FN), and terbinafine (TB) were performed in SD and incubated for 48 hours at 35°C. Cells from the MIC assays were spotted onto YPD medium and incubated at 30°C for 48 hours before plates were photographed. (C) Schematic of the S. cerevisiae Pkc1 cell wall integrity pathway.