Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:6.3.2.19 (ubiquitin-protein ligase)
 799 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The yeast ubiquitin-protein ligase Rsp5p regulates processes as diverse as polII transcription and endocytosis. Here, we identify Rsp5p in a screen for tRNA export (tex) mutants. The tex23-1/rsp5-3 mutant, which is complemented by RSP5, not only shows a strong nuclear accumulation of tRNAs at the restrictive temperature, but also is severely impaired in the nuclear export of mRNAs and 60S pre-ribosomal subunits. In contrast, nuclear localization sequence (NLS)-mediated nuclear protein import is unaffected in this mutant. Strikingly, the nuclear RNA export defects seen in the rsp5-3 strain are accompanied by a dramatic inhibition of both rRNA and tRNA processing, a combination of phenotypes that has not been reported for any previously characterized mutation in yeast. These data implicate ubiquitination as a mechanism coordinating the major nuclear RNA biogenesis pathways.
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PMID:Formation and nuclear export of tRNA, rRNA and mRNA is regulated by the ubiquitin ligase Rsp5p. 1460 72

The GATA transcription factors GLN3 and GAT1 activate nitrogen-regulated genes in Saccharomyces cerevisiae. NPR1 is a protein kinase that controls post-Golgi sorting of amino acid permeases. In the presence of a good nitrogen source, TOR (target of rapamycin) maintains GLN3 and NPR1 phosphorylated and inactive by inhibiting the type 2A-related phosphatase SIT4. We identified NPR1 as a regulator of GLN3. Specifically, loss of NPR1 causes nuclear translocation and activation of GLN3, but not GAT1, in nitrogen-rich conditions. NPR1-mediated inhibition of GLN3 is independent of the phosphatase SIT4. We also demonstrate that the E3/E4 ubiquitin-protein ligase proteins RSP5 and BUL1/2 are required for GLN3 activation under poor nitrogen conditions. Thus, NPR1 and BUL1/2 antagonistically control GLN3-dependent transcription, suggesting a role for regulated ubiquitination in the control of nutrient-responsive transcription.
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PMID:NPR1 kinase and RSP5-BUL1/2 ubiquitin ligase control GLN3-dependent transcription in Saccharomyces cerevisiae. 1524 35


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