Wang Feng, Li Shan, Cheng Kai-Wen, Rosencrans William M, Chou Tsui-Fen
Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
Proteome Exploration Laboratory, Beckman Institute, California Institute of Technology, Pasadena, CA 91125, USA.
Pharmaceuticals (Basel). 2022 Feb 7;15(2):204. doi: 10.3390/ph15020204.
The diverse modes of action of small molecule inhibitors provide versatile tools to investigate basic biology and develop therapeutics. However, it remains a challenging task to evaluate their exact mechanisms of action. We identified two classes of inhibitors for the p97 ATPase: ATP competitive and allosteric. We showed that the allosteric p97 inhibitor, UPCDC-30245, does not affect two well-known cellular functions of p97, endoplasmic-reticulum-associated protein degradation and the unfolded protein response pathway; instead, it strongly increases the lipidated form of microtubule-associated proteins 1A/1B light chain 3B (LC3-II), suggesting an alteration of autophagic pathways. To evaluate the molecular mechanism, we performed proteomic analysis of UPCDC-30245 treated cells. Our results revealed that UPCDC-30245 blocks endo-lysosomal degradation by inhibiting the formation of early endosome and reducing the acidity of the lysosome, an effect not observed with the potent p97 inhibitor CB-5083. This unique effect allows us to demonstrate UPCDC-30245 exhibits antiviral effects against coronavirus by blocking viral entry.
小分子抑制剂的多种作用模式为研究基础生物学和开发治疗方法提供了多功能工具。然而，评估其确切作用机制仍然是一项具有挑战性的任务。我们鉴定出了两类针对p97 ATP酶的抑制剂：ATP竞争性抑制剂和变构抑制剂。我们发现，变构p97抑制剂UPCDC-30245并不影响p97两个众所周知的细胞功能，即内质网相关蛋白降解和未折叠蛋白反应途径；相反，它会强烈增加微管相关蛋白1A/1B轻链3B（LC3-II）的脂化形式，这表明自噬途径发生了改变。为了评估分子机制，我们对用UPCDC-30245处理的细胞进行了蛋白质组学分析。我们的结果显示，UPCDC-30245通过抑制早期内体的形成并降低溶酶体的酸度来阻断内溶酶体降解，而强效p97抑制剂CB-5083并未观察到这种效应。这种独特的效应使我们能够证明UPCDC-30245通过阻断病毒进入表现出对冠状病毒的抗病毒作用。
