Deubiquitination of Dishevelled by Usp14 is required for Wnt signaling

Jung, Hwajin; Kim, B. G.; Han, Wonhee; Lee, J. H.; Cho, J. Y.; Park, W. S.; Maurice, Madelon M.; Han, Jin‐Kwan; Lee, Minjae; Finley, Daniel; Jho, Eek‐hoon

doi:10.1038/oncsis.2013.28

Cited by 103 publications

(89 citation statements)

References 34 publications

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“…We have previously shown that USP14 levels strongly correlate with β-catenin-mediated colon cancer development [35]. Among colon cancer cell lines, SW480, LOVO, DLD1, and Caco2 colon cancer cells have significantly or modestly increased levels of USP14 in contrast to HEK293 cells or HCT116 cells, which have lost USP14 expression because of somatic mutations [35].…”

Section: Resultsmentioning

confidence: 99%

Inactivation of USP14 Perturbs Ubiquitin Homeostasis and Delays the Cell Cycle in Mouse Embryonic Fibroblasts and in Fruit Fly Drosophila

Lee

Park

Yun

et al. 2018

Cell Physiol Biochem

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Background/Aims: The 26S proteasome is the key proteolytic complex for recognition and degradation of polyubiquitinated target substrates in eukaryotes. Among numerous proteasome-associated proteins, a deubiquitinating enzyme (DUB) USP14 has been identified as an endogenous inhibitor of the proteasome. Here, we explored the complex regulatory functions of USP14 that involve ubiquitin (Ub) homeostasis and substrate degradation in flies and mammals. Methods: USP14-null primary and immortalized mouse embryonic fibroblasts (MEFs) and USP14 knocked-down Drosophila were analyzed in this study. We measured proteasome and DUB activities using fluorogenic reporter substrates and adduct-forming probes. To examine the levels of ubiquitin, we performed immunoblotting and immunohistochemistry. Mass spectrometry (MS) was used to examine polyUb chain linkages and USP14-interacing proteins. Cell cycle was analyzed by flow cytometry, BrdU labeling, and phospho-histone H3 staining. Results: The homeostasis of Ub in USP14^–/–MEFs was markedly perturbed because of facilitated clearance of Ub. This phenomenon was recapitulated in muscles of USP14-deficient Drosophila with old ages. Absolute quantitation using MS also revealed that USP14^–/– MEFs contained significantly increased amounts of Ub, compared with wild-type. The key phenotype of USP14^–/– MEFs was their delayed proliferation originated from prolonged interphase possibly through aberrant degradation of cyclins A and B1. We found that knocking down USP14 in Drosophila resulted in delayed eye development associated with reduced mitotic activity. Conclusion: Our study identifies novel cellular functions of USP14 not only in cellular Ub hometostasis but also in cell cycle progression. USP14 was also essential for proper Drosophila eye development. These results strongly suggest that the USP14-mediated proteasome activity regulation may be directly related to various human diseases including cancer.

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Section: Resultsmentioning

confidence: 99%

Inactivation of USP14 Perturbs Ubiquitin Homeostasis and Delays the Cell Cycle in Mouse Embryonic Fibroblasts and in Fruit Fly Drosophila

Lee

Park

Yun

et al. 2018

Cell Physiol Biochem

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“…␤-Catenin, the key effector of the pathway, has been found to be targeted by multiple E3 ligases that are regulated by distinct stimuli in different contexts (12)(13)(14)(15)(16)(17). The roles of deubiquitinating enzymes in controlling the Wnt/␤-catenin pathway have also been exemplified in several studies, wherein they target either ␤-catenin, APC, or axin (20,21,37). Our present study extends these findings by defining for the first time the RING finger ubiquitin E3 ligase RNF220 as a ␤-catenin stabilizer through USP7-mediated deubiquitination, thereby suggesting a previously unknown broader role of ubiquitin E3 ligases.…”

Section: Discussionmentioning

confidence: 99%

“…Although the deubiquitinase FAM (USP9X) is able to target and stabilize ␤-catenin, it has been suggested to be mainly involved in the trafficking of ␤-catenin and E-cadherin in epithelia (19). USP14 was also found to be overexpressed in lung adenocarcinoma and able to stabilize ␤-catenin; however, it was shown to work by directly targeting the upstream regulator Dishevelled (Dvl) (20,21).…”

mentioning

confidence: 99%

The Ubiquitin Ligase RNF220 Enhances Canonical Wnt Signaling through USP7-Mediated Deubiquitination of β-Catenin

Yang

Kong

et al. 2014

Molecular and Cellular Biology

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Wnt/␤-catenin signaling plays critical roles in embryonic development and disease. Here, we identify RNF220, a RING domain E3 ubiquitin ligase, as a new regulator of ␤-catenin. RNF220 physically interacts with ␤-catenin, but instead of promoting its ubiquitination and proteasomal degradation, it stabilizes ␤-catenin and promotes canonical Wnt signaling. Our analysis showed that RNF220 interacts with USP7, a ubiquitin-specific peptidase, which is required for RNF220 to stabilize ␤-catenin. The RNF220/USP7 complex deubiquitinates ␤-catenin and enhances canonical Wnt signaling. Interestingly, the stability of RNF220 itself is negatively regulated by Gsk3␤, which is a key component of the ␤-catenin destruction complex and is inhibited upon Wnt stimulation. Accordingly, the RNF220/USP7 complex works as a positive feedback regulator of ␤-catenin signaling. In colon cancer cells with stimulated Wnt signaling, knockdown of RNF220 or USP7 impairs Wnt signaling and expression of Wnt target genes, suggesting a potentially novel role of RNF220 in Wnt-related tumorigenesis.

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“…S4), we hypothesized that USP14 might regulate autophagy through a nondegradative mechanism independently of K48 ubiquitination. Since USP14 can deubiquitinate K63 ubiquitin linkage (Jung et al 2013;Xu et al 2015a;Lee et al 2016), we considered the possibility that USP14 may regulate autophagy by deubiquitinating K63 ubiquitinated proteins. To directly test this possibility, we performed a quantitative mass spectrometry analysis to compare the changes in K63 ubiquitinated proteins with H4 cells expressing USP14 wild type and those expressing vector only or the USP14-AA mutant (Fig.…”

Section: Usp14 Regulates Beclin 1 K63-linked Ubiquitinationmentioning

confidence: 99%

USP14 regulates autophagy by suppressing K63 ubiquitination of Beclin 1

et al. 2016

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The ubiquitin-proteasome system (UPS) and autophagy are two major intracellular degradative mechanisms that mediate the turnover of complementary repertoires of intracellular proteomes. Simultaneously activating both UPS and autophagy might provide a powerful strategy for the clearance of misfolded proteins. However, it is not clear whether UPS and autophagy can be controlled by a common regulatory mechanism. K48 deubiquitination by USP14 is known to inhibit UPS. Here we show that USP14 regulates autophagy by negatively controlling K63 ubiquitination of Beclin 1. Furthermore, we show that activation of USP14 by Akt-mediated phosphorylation provides a mechanism for Akt to negatively regulate autophagy by promoting K63 deubiquitination. Our study suggests that Akt-regulated USP14 activity modulates both proteasomal degradation and autophagy through controlling K48 and K63 ubiquitination, respectively. Therefore, regulation of USP14 provides a mechanism for Akt to control both proteasomal and autophagic degradation. We propose that inhibition of USP14 may provide a strategy to promote both UPS and autophagy for developing novel therapeutics targeting neurodegenerative diseases.[Keywords: USP14; autophagy; Beclin 1; Akt] Supplemental material is available for this article. Autophagy and the ubiquitin-proteasome system (UPS) are two major intracellular degradative mechanisms that function in a complementary manner. UPS mediates the degradation of short-lived proteins conjugated with K48 ubiquitin chains (Komander and Rape 2012). On the other hand, autophagy mediates the turnover of long-lived proteins and intracellular organelles encapsulated in autophagosomes that eventually fuse with lysosomes to allow degradation by lysosomal proteases. Ubiquitination is also involved as a signaling mechanism in targeting both protein substrates and organelles such as depolarized mitochondria for degradation by autophagy (Sarraf et al. 2013;Ordureau et al. 2014). Ubiquitination of protein substrates is a reversible process, as ubiquitin chains can be removed by deubiquitinating enzymes (DUBs). Deubiquitination is an important negative regulatory mechanism for reducing the levels of protein ubiquitination. Ubiquitin-specific protease-14 (USP14), a DUB reversibly associated with the proteasome, has been shown to negatively regulate the activity of proteasomes by trimming K48 ubiquitin chains on proteasome-bound substrates (Borodovsky et al. 2001;Koulich et al. 2008;Lee et al. 2010). USP14 can also be activated by Akt-mediated phosphorylation, which promotes its deubiquitinating activity for both K48 and K63 ubiquitin linkages (Xu et al. 2015a). The activity of USP14 in deubiquitinating K63 ubiquitin linkages is likely to be physiologically relevant, as inhibition of USP14 in vivo leads to increases in the levels of K63-linked ubiquitin conjugates in both spinal cords and neurons (Vaden et al. 2015). However, the mechanism by which USP14 regulates K63 ubiquitination in control of cellular processes and its functional significance are...

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Deubiquitination of Dishevelled by Usp14 is required for Wnt signaling

Cited by 103 publications

References 34 publications

Inactivation of USP14 Perturbs Ubiquitin Homeostasis and Delays the Cell Cycle in Mouse Embryonic Fibroblasts and in Fruit Fly Drosophila

Inactivation of USP14 Perturbs Ubiquitin Homeostasis and Delays the Cell Cycle in Mouse Embryonic Fibroblasts and in Fruit Fly Drosophila

The Ubiquitin Ligase RNF220 Enhances Canonical Wnt Signaling through USP7-Mediated Deubiquitination of β-Catenin

USP14 regulates autophagy by suppressing K63 ubiquitination of Beclin 1

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