Fig. 3.

Processing of Stp2 in response to amino acids depends on the SPS system. A. Western blot analysis to detect Stp2 processing in response to amino acids. Candida albicans cells expressing a single STP2 allele tagged with mCherry (CaPM41) were grown for 4 h in yeast nitrogen base supplemented with 2% glucose at 30°C, at an initial OD₆₀₀ of 0.2. Cells were then exposed to yeast nitrogen base + 2% glucose or 1% casamino acids for the indicated time. Cell extracts were blotted and probed with an anti-mCherry antibody (see Materials and methods for details). The higher band corresponds to the unprocessed Stp2 (‘Unpr.’), whereas the lower one represents the processed version (‘Proc.’). B. Processing of Stp2 was not observed in ssy1Δ/Δ expressing STP2-mCherry (CaPM43) after exposure to glucose or amino acids for 1 h. As a control, an ssy1Δ/Δ strain expressing a truncated version STP2*-mCherry (CaPM45) lacking the N-terminal domain was included. Western blots were performed three independent times from biological replicates. Representative images are shown. (C) Growth and (D) pH was determined as stated in Fig. 1. Graphs show mean and standard deviation from three independent replicates.