Ergosterol homeostasis is a critical process for fungal cells. Paralogous zinc cluster transcription factors Upc2p and Ecm22p are major regulators of ergosterol biosynthesis in Saccharomyces cerevisiae. Upc2p and Ecm22p sense and respond to sterol depletion but their mechanism of activation has not been defined. Subcellular localization and functional expression of Upc2p-GFP and Ecm22p-GFP was monitored by fluorescence microscopy and flow cytometry in live yeast cells. Both fusion proteins localized to intracellular membranes and to perinuclear foci. Perinuclear localization of Upc2p-GFP and Ecm22p-GFP was increased when ergosterol biosynthesis was blocked by azole drug treatment. Nuclear localization in response to sterol depletion is consistent with the hypothesis that Upc2p and Ecm22p are trafficked from a membrane to the nucleus as a post-translational mechanism of sterol sensing.
|Evidence ID||Analyze ID||Interactor||Interactor Systematic Name||Interactor||Interactor Systematic Name||Type||Assay||Annotation||Action||Modification||Phenotype||Source||Reference||Note|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Gene Ontology Term||Gene Ontology Term ID||Qualifier||Aspect||Method||Evidence||Source||Assigned On||Reference||Annotation Extension|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Phenotype||Experiment Type||Experiment Type Category||Mutant Information||Strain Background||Chemical||Details||Reference|
|Evidence ID||Analyze ID||Regulator||Regulator Systematic Name||Target||Target Systematic Name||Experiment||Conditions||Strain||Source||Reference|