Isolation of UBP3, encoding a de-ubiquitinating enzyme, as a multicopy suppressor of a heat-shock mutant strain of S. cerevisiae.
Yeast strains lacking functional copies of the two genes SSA1 and SSA2, which encode cytosolic molecular chaperones, are temperature-sensitive. In this report, we describe the isolation of a high-copy suppressor of this temperature sensitivity, UBP3, which encodes a de-ubiquitinating enzyme. We show that ubp3 mutant yeast strains have a mild slow-growth phenotype and accumulate ubiquitin-protein conjugates. We propose a model in which Ubp3p acts in vivo to reverse the ubiquitination of substrate proteins, allowing temporarily misfolded proteins an opportunity to fold correctly.
Baxter
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BK
Department of Biomolecular Chemistry, University of Wisconsin, 1300 University Avenue, Madison, WI 53706, USA.
Craig
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EA
D000251:Adenosine Triphosphatases; D002455:Cell Division / Q000235:genetics / Q000502:physiology; D010450:Endopeptidases / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology; D005656:Fungal Proteins / Q000235:genetics / Q000502:physiology; D018628:Gene Dosage; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal / Q000235:genetics; D016153:Genes, Suppressor / Q000235:genetics; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics; D006360:Heat-Shock Proteins / Q000235:genetics; D016254:Mutagenesis, Insertional; D009154:Mutation / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics / Q000502:physiology*; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D038281:Silent Information Regulator Proteins, Saccharomyces cerevisiae; D014158:Transcription, Genetic / Q000235:genetics; D014452:Ubiquitins / Q000235:genetics / Q000378:metabolism / Q000502:physiology
D005656:Fungal Proteins; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D012097:Repressor Proteins; C061573:SIR4 protein, S cerevisiae; C542288:SSA2 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D038281:Silent Information Regulator Proteins, Saccharomyces cerevisiae; D014452:Ubiquitins; D010450:Endopeptidases; C101111:UBP3 protein, S cerevisiae; C091939:ubiquitin isopeptidase; D000251:Adenosine Triphosphatases; C095973:SSA1 protein, S cerevisiae