Intracellular localization of Saccharomyces cerevisiae GATA family transcription activator, Gln3, is used as a downstream readout of rapamycin-inhibited Tor1,2 control of Tap42 and Sit4 activities. Gln3 is cytoplasmic in cells provided with repressive nitrogen sources such as glutamine and is nuclear in cells growing with a derepressive nitrogen source such as proline or those treated with rapamycin or methionine sulfoximine (Msx). Although gross Gln3-Myc13 phosphorylation levels in wild type cells do not correlate with nitrogen source-determined intracellular Gln3-Myc13 localization, the phosphorylation levels are markedly influenced by several environmental perturbations. Msx treatment increases Snf1-independent Gln3-Myc13 phosphorylation, whereas carbon starvation increases both Snf1-dependent and -independent Gln3-Myc13 phosphorylation. Here we demonstrate that a broad spectrum of environmental stresses (temperature, osmotic, and oxidative) increase Gln3-Myc13 phosphorylation. In parallel, these stresses elicit rapid (<5 min for NaCl) Gln3-Myc13 relocalization from the nucleus to the cytoplasm. The response of Gln3-Myc13 localization to stressful conditions can completely overwhelm its response to nitrogen source quality or inhibitor-generated disruption of the Tor1,2 signal transduction pathway. Adding NaCl to cells cultured under conditions in which Gln3-Myc13 is normally nuclear, i.e. proline-grown, nitrogen-starved, Msx-, caffeine-, and rapamycin-treated wild type cells, or ure2Delta cells, results in its prompt relocalization to the cytoplasm. Together these data identify a major new level of regulation to which Gln3 responds, and adds a new dimension to mechanistic studies of the regulation of this transcription factor.
|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||Annotation Extension||Reference|
|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||Assay||Construct||Conditions||Strain Background||Reference|