Broad activation of the ubiquitin-proteasome system by Parkin is critical for mitophagy

Robert Graham, Nickie C. Chan, Anna M. Salazar, Anh H. Pham, Michael J. Sweredoski, Natalie J. Kolawa, Robert L J Graham, Sonja Hess, David C. Chan

    Research output: Contribution to journalArticlepeer-review


    Parkin, an E3 ubiquitin ligase implicated in Parkinson's disease, promotes degradation of dysfunctional mitochondria by autophagy. Using proteomic and cellular approaches, we show that upon translocation to mitochondria, Parkin activates the ubiquitin-proteasome system (UPS) for widespread degradation of outer membrane proteins. This is evidenced by an increase in K48-linked polyubiquitin on mitochondria, recruitment of the 26S proteasome and rapid degradation of multiple outer membrane proteins. The degradation of proteins by the UPS occurs independently of the autophagy pathway, and inhibition of the 26S proteasome completely abrogates Parkin-mediated mitophagy in HeLa, SH-SY5Y and mouse cells. Although the mitofusins Mfn1 and Mfn2 are rapid degradation targets of Parkin, we find that degradation of additional targets is essential for mitophagy. These results indicate that remodeling of the mitochondrial outer membrane proteome is important for mitophagy, and reveal a causal link between the UPS and autophagy, the major pathways for degradation of intracellular substrates. © The Author 2011. Published by Oxford University Press. All rights reserved.
    Original languageEnglish
    Article numberddr048
    Pages (from-to)1726-1737
    Number of pages11
    JournalHuman Molecular Genetics
    Issue number9
    Publication statusPublished - May 2011


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