Small molecules have been discovered to stimulate the 20S core particle (CP) of the proteasome to degrade proteins. However, the impact a 20S CP stimulator can have on the regulation of protein levels has not been fully characterized. Previous studies have focused on using one kind of stimulator to enhance the degradation of specific 20S CP substrates. We present here a study that utilizes several 20S CP stimulators to determine how each can affect the degradation of proteins in a biochemical assay with purified proteins and of an overexpressed GFP-fusion protein in cells. We also evaluate the effects of two stimulators on the whole cellular proteome in HEK-293T cells using label-free quantitative proteomic analysis for a broader understanding on their impact. Our studies demonstrate that 20S CP stimulation is likely to promote the degradation of significantly disordered proteins; however, the specific effect on the regulation of protein levels appears to be dependent on the mechanism of action of each stimulator due to the dynamic nature of the 20S CP. Our results reveal the potential of tailoring small molecule stimulators to influence the degradation of certain protein types and 20S CP substrates.

中文翻译：

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蛋白质降解曲线揭示了 20S 蛋白酶体小分子刺激的动态特性

已发现小分子可刺激蛋白酶体的 20S 核心颗粒 (CP) 降解蛋白质。然而，20S CP 刺激剂对蛋白质水平调节的影响尚未完全表征。以前的研究集中在使用一种刺激剂来增强特定 20S CP 底物的降解。我们在此介绍了一项研究，该研究利用几个 20S CP 刺激器来确定每种刺激器如何影响纯化蛋白质和细胞中过度表达的 GFP 融合蛋白的生化测定中蛋白质的降解。我们还使用无标记定量蛋白质组学分析评估了两种刺激剂对 HEK-293T 细胞中整个细胞蛋白质组的影响，以更广泛地了解它们的影响。我们的研究表明，20S CP 刺激可能会促进显着无序蛋白质的降解；然而，由于 20S CP 的动态特性，对蛋白质水平调节的具体影响似乎取决于每个刺激剂的作用机制。我们的结果揭示了定制小分子刺激剂以影响某些蛋白质类型和 20S CP 底物降解的潜力。