A deubiquitinating enzyme interacts with SIR4 and regulates silencing in S. cerevisiae.
The SIR2, SIR3, and SIR4 proteins are required for silencing of transcription at the silent mating type loci and at telomeres in yeast. Using protein affinity chromatography, we show that SIR2, SIR3, and two proteins of 69 and 110 kDa tightly associate with SIR4. Surprisingly, the 110 kDa SIR4-binding protein is identical to UBP3, one of several previously described yeast enzymes that deubiquitinate target proteins. Deletion of the UBP3 gene results in markedly improved silencing of genes inserted either near a telomere or at one of the silent mating type loci, indicating that UBP3 is an inhibitor of silencing. We discuss possible roles for UBP3 in controlling the activity or assembly of the SIR protein complex.
Moazed
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Department of Microbiology, University of California, San Francisco 94143, USA.
Johnson
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D000595:Amino Acid Sequence; D002352:Carrier Proteins / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism; D010450:Endopeptidases; D005656:Fungal Proteins / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D006655:Histone Deacetylases; D000072235:Mating Factor; D008969:Molecular Sequence Data; D010455:Peptides / Q000378:metabolism; D011485:Protein Binding; D012097:Repressor Proteins / Q000502:physiology; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D038281:Silent Information Regulator Proteins, Saccharomyces cerevisiae; D056565:Sirtuin 2; D037761:Sirtuins; D016615:Telomere / Q000502:physiology; D015534:Trans-Activators / Q000378:metabolism; D014452:Ubiquitins / Q000378:metabolism*
D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D010455:Peptides; D012097:Repressor Proteins; C084122:SIR3 protein, S cerevisiae; C061573:SIR4 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D038281:Silent Information Regulator Proteins, Saccharomyces cerevisiae; D015534:Trans-Activators; D014452:Ubiquitins; D000072235:Mating Factor; D010450:Endopeptidases; C101111:UBP3 protein, S cerevisiae; C087778:SIR2 protein, S cerevisiae; D056565:Sirtuin 2; D037761:Sirtuins; D006655:Histone Deacetylases