Zhao Wenting, Bachhav Bhagyashree, McWhite Claire, Segatori Laura
Department of Chemical and Biomolecular Engineering, Rice University, Houston TX, USA.
Department of BioSciences, Rice University, Houston TX, USA.
Protein Eng Des Sel. 2018 Nov 1;31(11):437-445. doi: 10.1093/protein/gzz006.
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.
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蛋白质的降解，并调节真核细胞中天然蛋白质的周转，从而在维持蛋白质稳态中发挥关键作用。UPS已成为多种以错误折叠或聚集蛋白质积累为特征的疾病的药物靶点。虽然增强UPS活性被广泛认为是防止异常、偏离途径的蛋白质构象积累并改善多种蛋白质错误折叠疾病表型的一种有前景的策略，但蛋白酶体降解激活的分子机制仍不清楚。我们报告了一种用于全基因组筛选UPS激活剂的酵母筛选平台的开发。我们对酿酒酵母选择标记乳清苷-5'-磷酸脱羧酶（URA3）进行了工程改造，使其通过与UPS敏感标签融合而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活性与细胞生长联系起来。本研究中报道的酵母筛选平台将为高通量、全基因组研究开辟道路，旨在鉴定可能为治疗应用提供新靶点的UPS功能调节剂。
