Discovery of a Potent and Selective Degrader for USP7
Yuan PeiJingfeng FuYunkai ShiMengmeng ZhangGuanghao LuoXiaomin LuoNing SongTian MiYaxi YangJia LiYubo ZhouBing Zhou
7
Citation
63
Reference
10
Related Paper
Citation Trend
Abstract:
Abstract The tumor suppressor p53 is the most frequently mutated gene in human cancer and more than half of cancers contain p53 mutations. The development of novel and effective therapeutic strategies for p53 mutant cancer therapy is a big challenge and highly desirable. Ubiquitin‐specific protease 7 (USP7), also known as HAUSP, is a deubiquitinating enzyme and proposed to stabilize the oncogenic E3 ubiquitin ligase MDM2 that promotes the proteosomal degradation of p53. Herein, we report the design and characterization of U7D‐1 as the first selective USP7‐degrading Proteolysis Targeting Chimera (PROTAC). U7D‐1 showed selective and effective USP7 degradation, and maintained potent cell growth inhibition in p53 mutant cancer cells, with USP7 inhibitor showing no activity. These data clearly demonstrated the practicality and importance of PROTAC as a preliminary chemical tool for investigating USP7 protein functions and a promising method for potential p53 mutant cancer therapy.Keywords:
Deubiquitinating enzyme
Proteolysis
MDMX
The tumor suppressor p53 protein is tightly regulated by a ubiquitin-proteasomal degradation mechanism. Several E3 ubiquitin ligases, including MDM2 (mouse double minute 2), have been reported to play an essential role in the regulation of p53 stability. However, it remains unclear how the activity of these E3 ligases is regulated. Here, we show that the HECT-type E3 ligase Smurf1/2 (Smad ubiquitylation regulatory factor 1/2) promotes p53 degradation by enhancing the activity of the E3 ligase MDM2. We provide evidence that the role of Smurf1/2 on the p53 stability is not dependent on the E3 activity of Smurf1/2 but rather is dependent on the activity of MDM2. We find that Smurf1/2 stabilizes MDM2 by enhancing the heterodimerization of MDM2 with MDMX, during which Smurf1/2 interacts with MDM2 and MDMX. We finally provide evidence that Smurf1/2 regulates apoptosis through p53. To our knowledge, this is the first report to demonstrate that Smurf1/2 functions as a factor to stabilize MDM2 protein rather than as a direct E3 ligase in regulation of p53 degradation. The tumor suppressor p53 protein is tightly regulated by a ubiquitin-proteasomal degradation mechanism. Several E3 ubiquitin ligases, including MDM2 (mouse double minute 2), have been reported to play an essential role in the regulation of p53 stability. However, it remains unclear how the activity of these E3 ligases is regulated. Here, we show that the HECT-type E3 ligase Smurf1/2 (Smad ubiquitylation regulatory factor 1/2) promotes p53 degradation by enhancing the activity of the E3 ligase MDM2. We provide evidence that the role of Smurf1/2 on the p53 stability is not dependent on the E3 activity of Smurf1/2 but rather is dependent on the activity of MDM2. We find that Smurf1/2 stabilizes MDM2 by enhancing the heterodimerization of MDM2 with MDMX, during which Smurf1/2 interacts with MDM2 and MDMX. We finally provide evidence that Smurf1/2 regulates apoptosis through p53. To our knowledge, this is the first report to demonstrate that Smurf1/2 functions as a factor to stabilize MDM2 protein rather than as a direct E3 ligase in regulation of p53 degradation.
MDMX
Ubiquitin-Protein Ligases
Cite
Citations (75)
Laparoscopic surgery is the main treatment method for patients with gastrointestinal malignant tumors. Although laparoscopic surgery is minimally invasive, its tool stimulation and pneumoperitoneum pressure often cause strong stress reactions in patients. On the other hand, gastrointestinal surgery can cause stronger pain in patients, compared to other surgeries. Transversus abdominis plane block (TAPB) can effectively inhibit the transmission of nerve impulses caused by surgical stimulation, alleviate patient pain, and thus alleviate stress reactions. Remazolam is an acting, safe, and effective sedative, which has little effect on hemodynamics and is suitable for most patients. TAPB combined with remazolam can reduce the dosage of total anesthetic drugs, reduce adverse reactions, reduce stress reactions, and facilitate the rapid postoperative recovery of patients.
Deubiquitinating enzyme
Cite
Citations (48)
Deubiquitination has emerged as an important mechanism of p53 regulation. A number of deubiquitinating enzymes(DUBs) from the ubiquitin-specific protease family have been shown to regulate the p53-MDM2-MDMX networks. We recently reported that Otub1, a DUB from the OTU-domain containing protease family, is a novel p53 regulator. Interestingly, Otub1 abrogates p53 ubiquitination and stabilizes and activates p53 in cells independently of its deubiquitinating enzyme activity. Instead, it does so by inhibiting the MDM2 cognate ubiquitin-conjugating enzyme(E2) UbcH5. Otub1 also regulates other biological signaling through this non-canonical mechanism, suppression of E2, including the inhibition of DNA-damage-induced chromatin ubiquitination. Thus, Otub1 evolves as a unique DUB that mainly suppresses E2 to regulate substrates. Here we review the current progress made towards the understanding of the complex regulation of the p53 tumor suppressor pathway by DUBs, the biological function of Otub1 including its positive regulation of p53, and the mechanistic insights into how Otub1 suppresses E2.
Deubiquitinating enzyme
MDMX
Cite
Citations (0)
Deubiquitination has emerged as an important mechanism of p53 regulation. A number of deubiquitinating enzymes(DUBs) from the ubiquitin-specific protease family have been shown to regulate the p53-MDM2-MDMX networks. We recently reported that Otub1, a DUB from the OTU-domain containing protease family, is a novel p53 regulator. Interestingly, Otub1 abrogates p53 ubiquitination and stabilizes and activates p53 in cells independently of its deubiquitinating enzyme activity. Instead, it does so by inhibiting the MDM2 cognate ubiquitin-conjugating enzyme(E2) UbcH5. Otub1 also regulates other biological signaling through this non-canonical mechanism, suppression of E2, including the inhibition of DNA-damage-induced chromatin ubiquitination. Thus, Otub1 evolves as a unique DUB that mainly suppresses E2 to regulate substrates. Here we review the current progress made towards the understanding of the complex regulation of the p53 tumor suppressor pathway by DUBs, the biological function of Otub1 including its positive regulation of p53, and the mechanistic insights into how Otub1 suppresses E2.
Deubiquitinating enzyme
MDMX
Cite
Citations (0)
MDM2 is an E3 ubiquitin ligase that targets p53 for proteasomal degradation. Recent studies have shown, however, that the ring-finger domain (RFD) of MDM2, where the ubiquitin E3 ligase activity resides, is necessary but not sufficient for p53 ubiquitination, suggesting that an additional activity of MDM2 might be required. To test this possibility, we generated a series of MDM2/MDMX chimeric proteins to assess the contribution of each domain of MDM2 to the ubiquitination process. MDMX is a close structural homolog of MDM2 that nevertheless lacks the E3 ligase activity in vivo. We demonstrate here that MDMX gains self-ubiquitination activity and becomes extremely unstable upon introduction of the MDM2 RFD, indicating that the RFD is essential for self-ubiquitination. This MDMX chimeric protein, however, is unable to ubiquitinate p53 in vivo despite its E3 ligase activity and binding to p53, separating the self-ubiquitination activity of MDM2 from its ability to ubiquitinate p53. Significantly, fusion of the central acidic domain (AD) of MDM2 to the MDMX chimeric protein renders the protein fully capable of ubiquitinating p53, and p53 ubiquitination is associated with p53 degradation and nuclear export. Moreover, the AD mini protein expressed in trans can functionally rescue the AD-lacking MDM2 mutant, further supporting a critical role for the AD in MDM2-mediated p53 ubiquitination.
Ubiquitin-Protein Ligases
Cite
Citations (116)
MDMX
Cite
Citations (21)
MDMX
Ubiquitin-Protein Ligases
Cite
Citations (61)
Abstract The overexpression of Mdm2 has been linked to the loss of p53 tumour suppressor activity in several human cancers. Here, we present results suggesting that ubiquitin-specific peptidase 48 (USP48), a deubiquitinase that has been linked in previous reports to the NF-κB signaling pathway, is a novel Mdm2 binding partner that promotes Mdm2 stability and enhances Mdm2-mediated p53 ubiquitination and degradation. In contrast to other deubiquitinating enzymes (DUBs) that have been previously implicated in the regulation of Mdm2 protein stability, USP48 did not induce Mdm2 stabilization by significantly reducing Mdm2 ubiquitination levels. Moreover, two previously characterized USP48 mutants lacking deubiquitinase activity were also capable of efficiently stabilizing Mdm2, indicating that USP48 utilizes a non-canonical, deubiquitination-independent mechanism to promote Mdm2 oncoprotein stability. This study represents, to the best of our knowledge, the first report suggesting DUB-mediated target protein stabilization that is independent of its deubiquitinase activity. In addition, our results suggest that USP48 might represent a new mechanism of crosstalk between the NF-κB and p53 stress response pathways.
Deubiquitinating enzyme
Ubiquitins
Crosstalk
MDMX
Immunoprecipitation
Cite
Citations (25)
E3 ubiquitin ligases are of interest as drug targets for their ability to regulate protein stability and function. The oncogene Mdm2 is an attractive E3 ligase to target, as it is the key negative regulator of the tumor suppressor p53, which controls the transcription of genes involved in cell fate. Overexpression of Mdm2 facilitates tumorigenesis by inactivating p53, and through p53-independent oncogenic effects. We developed a high-throughput cellular Mdm2 auto-ubiquitination assay, which we used to discover a class of small-molecule Mdm2 ligase activity inhibitors. These compounds inhibit Mdm2 and p53 ubiquitination in cells, reduce viability of cells with wild-type p53, and synergize with DNA-damaging agents to cause cell death. We determined that these compounds effectively inhibit the E3 ligase activity of the Mdm2-MdmX hetero-complex. This mechanism may be exploitable to create a new class of anti-tumor agents.
MDMX
Ubiquitin-Protein Ligases
Cite
Citations (90)
Abstract The RING domain of MDM2 that is essential for its E3 ligase activity mediates binding to itself and its structural homologue MDMX. Whereas it has been reported that RING domain interactions are critical, it is not well understood how they affect the E3 ligase activity of MDM2. We report that the E3 ligase activity requires the RING domain–dependent complex formation. In vivo, MDM2 and MDMX hetero-RING complexes are the predominant form versus the MDM2 homo-RING complex. Importantly, the MDM2/MDMX hetero-RING complexes exhibit a greater E3 ligase activity than the MDM2 homo-RING complexes. Disruption of the binding between MDM2 and MDMX resulted in a marked increase in both abundance and activity of p53, emphasizing the functional importance of this heterocomplex in p53 control. [Cancer Res 2007;67(13):6026–30]
MDMX
Ubiquitin-Protein Ligases
Cite
Citations (153)