Evaluating Signal Response of Wsc2p and Wsc3p Cell Wall Stress Sensors in Yeast

Abstract

In the budding yeast Saccharomyces cerevisiae, the WSC2 and WSC3 genes encode plasma membrane proteins with structural features of cell wall stress sensors involved in maintenance of cell integrity and recovery from heat shock. These sensors detect changes in environmental conditions and stresses on the cell wall and/or the plasma membrane and activate a downstream PKC1‐dependent cell wall integrity pathway (CWIP) with a central Mitogen Activated Protein (MAP) kinase Slt2/Mpk1 module. The objective of our research is to evaluate which interactor proteins, among those previously identified by an integrated membrane yeast two‐hybrid (iMYTH) assay, are shared between the sensors and if these contribute to CWIP activation. We hypothesize that some signaling functions of Wsc2p and Wsc3p in Saccharomyces cerevisiae require specific interactions with couplers of the PKC1 pathway. A functional interaction network diagram was generated to visualize these interactions. To reinforce our analysis we performed bioinformatic analysis in order to identify orthologous proteins for these interactors in other fungal species. Viability assays were performed on null mutant strains of the interactors under normal culture conditions and during exposure to cell wall stress conditions. Growth constants for all the deletion mutants were calculated and compared to the constants calculated for the wild type. This research was supported in part by the Univ. of Puerto Rico, Univ. of Toronto, Univ. of Kentucky, and NIH awards from RCMI‐G12MD007600, and INBRE 8 P20 GM103475.