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Published July 11, 2014 | Published
Journal Article Open

Degradation of the Deubiquitinating Enzyme USP33 is Mediated by p97 and the Ubiquitin Ligase HERC2


Because the deubiquitinating enzyme USP33 is involved in several important cellular processes (β-adrenergic receptor recycling, centrosome amplification, RalB signaling, and cancer cell migration), its levels must be carefully regulated. Using quantitative mass spectrometry, we found that the intracellular level of USP33 is highly sensitive to the activity of p97. Knockdown or chemical inhibition of p97 causes robust accumulation of USP33 due to inhibition of its degradation. The p97 adaptor complex involved in this function is the Ufd1-Npl4 heterodimer. Furthermore, we identified HERC2, a HECT-domain-containing E3 ligase, as responsible for polyubiquitination of USP33. Inhibition of p97 causes accumulation of polyubiquitinated USP33, suggesting that p97 is required for post-ubiquitination processing. Thus, our study has identified several key molecules that control USP33 degradation within the ubiquitin-proteasome system.

Additional Information

© 2014, The American Society for Biochemistry and Molecular Biology. Received March 27, 2014. Accepted May 22, 2014. First Published on May 22, 2014. We are grateful for help from the following: Tomohiko Ohta for HERC2 constructs that helped us to reconstruct full-length HERC2; William G. Kaelin Jr. for the 786-O and RCC4 cell lines; Tsui-Fen Chou (Harbor-UCLA Medical Center) for helpful discussions and reagents during the early stage of this work; Robert Graham (currently at University of Manchester) from the PEL for technical help with the mass spectrometry experiments; Michael Walters and Lev G. Lis (University of Minnesota) for NMS-873. The PEL is supported by the Gordon and Betty Moore Foundation through grant GBMF775 and the Beckman Institute. This work was funded by the Howard Hughes Medical Institute and NIH RO1 GM062967.

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Published - J._Biol._Chem.-2014-Chan-19789-98.pdf


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