Celebration of Scholarship and Creative Activity 2021
Despite the important role of manganese (Mn) in both bacteria and mammalian hosts, little is known about the molecular mechanisms by which Mn levels are controlled. This study examined two Mn homeostasis proteins in E. coli, MntP and MntS. At high Mn concentrations, MntP exports Mn out of the cell. The role of MntS is unknown, however its overproduction in the presence of Mn causes high Mn concentrations and leads to bacterial cell death; mimicking cells that lack an MntP exporter. We hypothesize that MntS inhibits MntP in E. coli, either by blocking MntP export activity or decreasing MntP levels. Two experiments were performed to gain insight into MntS localization within the cell and to examine the mechanisms in which MntS may affect MntP. To detect subcellular localization of MntS, we used a MntS-GFP and control GFP fusion proteins. We observed high GFP fluorescence with MntS-GFP. Since GFP is only active in the cytoplasm, we conclude that MntS is located in the cytoplasm. To determine whether MntS inhibits MntP activity or abundance, we examined MntP levels in the presence or absence of MntS. Western blotting results showed higher MntP levels with MntS. This indicates that MntP is more stable in the presence of MntS and does not support our initial hypothesis. Overall, this study can be used to better understand Mn homeostasis in pathogenic bacteria.