Trk1p expression modulates Pma1p activity in Saccharomyces cerevisiae

Extracellular pH changes with varying dextrose concentrations

Abstract

This study investigates the role of the potassium ion channel Trk1p in modulating the activity of the proton ATPase Pma1p in Saccharomyces cerevisiae. We evaluated the impact of Trk1p expression on Pma1p activity and yeast cell growth by examining changes in extracellular pH and growth rates at various D-glucose concentrations. Our experimental design included two approaches: measuring extracellular pH as a proxy for Pma1p activity and assessing growth rates under different glucose conditions for TRK1 and trk1-∆ strains. We observed a significant difference in extracellular pH between the wild type and mutant strains across various glucose concentrations, suggesting that Trk1p modulates Pma1p activity. However, this modulation did not result in significant differences in growth rates between replicates of the same strain, indicating that changes in Pma1p activity do not affect yeast growth under the conditions tested. This study is significant in demonstrating that Pma1p is a central regulator of ion homeostasis with its modulation by Trk1p offering insight into potential antifungal drug targets. These findings propose that other ATPases may compensate for the reduced activity of Pma1p in the mutant, highlighting the complexity of ion regulatory mechanisms in yeast.