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Merck

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

The Journal of biological chemistry (2017-10-04)
Monica Boselli, Byung-Hoon Lee, Jessica Robert, Miguel A Prado, Sang-Won Min, Chialin Cheng, M Catarina Silva, Changhyun Seong, Suzanne Elsasser, Ketki M Hatle, Timothy C Gahman, Steven P Gygi, Stephen J Haggarty, Li Gan, Randall W King, Daniel Finley
RESUMEN

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.

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Sigma-Aldrich
Anti-GAPDH antibody produced in rabbit, ~1 mg/mL, affinity isolated antibody, buffered aqueous solution
Sigma-Aldrich
Anticuerpo anti-Tau-1, clon PC1C6, clone PC1C6, Chemicon®, from mouse
Sigma-Aldrich
Anticuerpo anti-Tau, a.a. 210-241, clon Tau-5, ascites fluid, clone Tau-5, Chemicon®
Sigma-Aldrich
Anti-Actin (20-33) antibody produced in rabbit, IgG fraction of antiserum, buffered aqueous solution
Sigma-Aldrich
IU1-47, ≥98% (HPLC)