An inhibitor of the proteasomal deubiquitinating enzyme USP14 induces tau elimination in cultured neurons

作者：Boselli Monica; Lee Byung Hoon; Robert Jessica; Prado Miguel A; Min Sang Won; Cheng Chialin; Silva M Catarina; Seong Changhyun; Elsasser Suzanne; Hatle Ketki M; Gahman Timothy C; Gygi Steven P; Haggarty Stephen J; Gan Li; King Randall W^*; Finley Daniel^*

来源：JOURNAL OF BIOLOGICAL CHEMISTRY, 2017, 292(47): 19209-19225.

DOI：10.1074/jbc.M117.815126

• neurodegenerative disease
• proteasome
• small molecule
• tauopathy
• ubiquitin
• IU1
• IU1-47

The ubiquitin-proteasome system (UPS) is responsible for most selective protein degradation in eukaryotes and regulates numerous cellular processes, including cell cycle control and protein quality control. A component of this system, the deubiquitinating enzyme USP14, associates with the proteasome where it can rescue substrates from degradation by removal of the ubiquitin tag. We previously found that a small-molecule inhibitor of USP14, known as IU1, can increase the rate of degradation of a subset of proteasome substrates. We report here the synthesis and characterization of 87 variants of IU1, which resulted in the identification of a 10-fold more potent USP14 inhibitor that retains specificity for USP14. The capacity of this compound, IU1-47, to enhance protein degradation in cells was tested using as a reporter the microtubule-associated protein tau, which has been implicated in many neurodegenerative diseases. Using primary neuronal cultures, IU1-47 was found to accelerate the rate of degradation of wild-type tau, the pathological tau mutants P301L and P301S, and the A152T tau variant. We also report that a specific residue in tau, lysine 174, is critical for the IU1-47-mediated tau degradation by the proteasome. Finally, we show that IU1-47 stimulates autophagic flux in primary neurons. In summary, these findings provide a powerful research tool for investigating the complex biology of USP14.

• 出版日期2017-11-24