The ubiquitin proteasome system (UPS) is a complex cellular machinery that catalyzes degradation of misfolded or damaged proteins and regulates turnover of native proteins in eukaryotic cells, thus playing a crucial role in maintaining protein homeostasis. The UPS has emerged as a drug target for a diverse range of diseases characterized by accumulation of misfolded or aggregated proteins. While enhancement of UPS activity is widely recognized as a promising strategy to prevent accumulation of aberrant, off-pathway protein conformations and ameliorate the phenotypes of a wide range of protein misfolding diseases, the molecular mechanisms underlying activation of proteasomal degradation are poorly characterized. We report the development of a yeast selection platform for genome-wide selection of UPS activators. We engineered the Saccharomyces cerevisiae selection marker orotidine-5′-phosphate decarboxylase (URA3) to function as a substrate of proteasomal degradation through fusion to UPS-sensitive tags. The resulting UPS-sensitive URA3 variant links UPS activity to cell growth. The yeast selection platform reported in this study will open the way to high-throughput, genome-wide studies aimed at identifying modulators of UPS function that might provide novel target for therapeutic applications.

中文翻译：

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用于检测蛋白酶体活化的酵母选择系统

泛素蛋白酶体系统（UPS）是一种复杂的细胞机制，可催化错误折叠或受损的蛋白质降解并调节真核细胞中天然蛋白质的周转率，因此在维持蛋白质稳态方面起着至关重要的作用。UPS已成为各种疾病的药物靶标，这些疾病的特征是蛋白质折叠错误或聚集。虽然普遍认为UPS活性的增强是防止异常的，偏离路径的蛋白质构象积累并改善多种蛋白质错误折叠疾病的表型的有前途的策略，但蛋白酶体降解激活的分子机制尚不明确。我们报告了用于全基因组选择UPS激活剂的酵母选择平台的发展。我们设计了酿酒酵母选择标记orotidine-5'-磷酸脱羧酶（URA3），以通过与UPS敏感标签融合来作为蛋白酶体降解的底物。由此产生的对UPS敏感的URA3变体将UPS活动与细胞生长联系起来。这项研究中报道的酵母选择平台将为高通量，全基因组研究开辟道路，这些研究旨在确定UPS功能的调节剂，这些调节剂可能为治疗应用提供新的靶标。