Discovery of biological functions associated with Mtl1p mechanosensor of Saccharomyces sereviciae

Functional analysis of the Mtl1 protein in Saccharomyces cerevisiae has revealed that this transmembrane sensor endows yeast cells with resistance to oxidative stress by hydrogen peroxide (H2O2) treatment through a signaling mechanism called the cell wall integrity pathway (CWI). Quantitative mRNA expression analysis revealed that genes containing the Stress Response Element (STRE) element 5-AGGGG-3, a regulatory sequence recognized by activating Transcription Factors (TFs) Msn2 and Msn4, were transcriptionally repressed by 2-fold or greater in the mtl1delta strains. Since these TFs are negatively regulated by PKA, this observation suggests that Mtl1p signaling modulates the inhibitory activity of PKA over the transcription of specific stress response genes. Upregulation of multiple heat shock proteins (HSPs) and the phosphatase subunit of trehalose 6-phosphate synthase suggests that mtl1delta strains undergo intrinsic activation of a non-lethal heat stress response, which appears to be controlled by Mtl1p.