Cells respond to an accumulation of unfolded proteins in the endoplasmic reticulum (ER) by increasing transcription of genes encoding ER-resident proteins. The information is transmitted from the ER lumen to the nucleus by an intracellular signaling pathway, the unfolded protein response (UPR). We have identified a basic-leucine zipper transcription factor, Hac1p, that is required for the UPR and binds to the UPR element in the promoter of UPR-regulated genes. Surprisingly, Hac1p is found in UPR-activated cells only, and its level is controlled by regulated splicing of its mRNA. Splicing replaces the C-terminal tail of Hac1p with a different peptide that renders Hac1p more resistant to an otherwise extremely rapid ubiquitin-dependent degradation. We propose that the complex regulation of Hac1p expression serves to provide multiple levels at which the UPR can be controlled.
|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|