The Dependency Map (DepMap) is a genome-wide pooled
CRISPR-Cas9 knockout proliferation screen conducted in more than 700 cancer cell lines spanning many
different tumor lineages. Each cell line in the DepMap contains a unique barcode, and each gene
knockout is assigned a “dependency score” on a per cell-line basis which quantifies the rate of
CRISPR-Cas9 guide drop. It has been found that proteins with similar DepMap scores across cell
lines, a phenomenon known as co-dependent genes, have closely related biological functions. This can
include activity in the same or parallel pathways or membership in the same protein complex or the
same pathway.
We identified the strongest seven co-dependent genes (“Symbol”) for DUBs and ran GO enrichment
analysis. We used Biogrid, IntAct, and Pathway Commons PPIDs, and the NURSA protein-protein
interaction databases (PPIDs) to determine whether co-dependent genes interact with one another. The
“Evidence” column contains the PPIDs in which the interaction appears as well as whether there is
support for the association by an INDRA statement. As another approach to identify potential
interactors, we looked at proteomics data from the Broad Institute's Cancer Cell Line Encyclopedia (CCLE) for
proteins whose expression across ~375 cell lines strongly correlated with the abundance of each DUB;
it has previously been observed that proteins in the same complex are frequently significantly
co-expressed. The correlations and associated p-values in the CCLE proteomics dataset are provided.
And, we determined whether co-dependent genes yield similar transcriptomic signatures
in the Broad Institute's Connectivity
Map (CMap). A CMap score greater than 90 is considered significantly similar.
Using the biological processes and other Gene Ontology terms from well characterized DUBs as a
positive control, several gene set enrichment analyses were considered. Threshold-less methods
like GSEA had relatively poor results.
Over-representation analysis with a threshold of of the top 7 highest absolute value Dependency Map
correlations yielded the best results and is reported below.
GO Identifier
GO Name
GO Type
p-value
p-value (adj.)
q-value
Transcriptomics
The following table shows the significantly differentially expressed genes after knocking
out USP13 using CRISPR-Cas9.
There were too few differentially expressed genes to run a meaningful GSEA.
Literature Mining
INDRA was used to automatically assemble known mechanisms
related to USP13 from literature and knowledge bases.
The first section shows only DUB activity and the second shows all other results.
We demonstrated that polyubiquitination of RAP80 blocks its interaction with polyubiquitin chain and deubiquitination of RAP80 by USP13 facilitate the interaction between RAP80 and polyubiquitin chain.
Together with results showing USP13 is important for DDR and RAP80 localization at the sites of DNA damage, we hypothesized that RAP80 ubiquitination is inhibitory of its function, and deubiquitination of RAP80 by USP13 following DNA damage promotes RAP80 function in the DDR pathway.
We found that following DNA damage, a deubiquitinase, USP13, deubiquitinates RAP80 and promotes binding between RAP80 and K63 linked polyubiquitin chains, which is important for the recruitment of the RAP80 and BRCA1 complex to DSBs to facilitate DDR.
Consistent with this, we found that RAP80 ubiquitination decreases following DNA damage (XREF_FIG and XREF_SUPPLEMENTARY), suggesting that USP13 promotes RAP80 deubiquitination following DNA damage.
Recent studies indicated that USP13 can deubiquitinate and regulate protein levels of Beclin-1, microphathalmia associated transcription factor, Siah2, phosphatase and tensin homolog, and STAT-1, and the deubiquitination process of USP13 could also be orchestrated by Beclin-1.
While A20 inhibits PtdIns3P signaling by removing the TRAF6-dependent Lys63-linked chains from Beclin 1, the enzymes USP10 and USP13 prevent PI3K-III complex components from their degradation and, therefore, support autophagy. Interestingly enough, USP10 also stabilizes p53, which, in turn, triggers the degradation of Beclin 1 and VPS34 in order to prevent autophagy.
It promotes the degradation of Vps34 complexes by inhibiting USP10 and USP13, two ubiquitin specific peptidases that target the deubiquitination of Beclin-1.
Conversely, it was show that Beclin 1 is deubiquitinated by USP10 and USP13 and adding complexity, Beclin 1 itself controlled the protein stabilities of USP10 and USP13 by regulating their deubiquitinating activities, in turn regulating the levels of tumor suppressor p53 [XREF_BIBR].
Specific and potent autophagy inhibitor-1 (Spautin-1) was identified to inhibit USP10 and USP13, which deubiquitinate the Beclin 1 subunit of Vsp34 complex, and thus promoted the degradation of Vsp34 PI3 kinase complex.
Wild-type USP13 purified from either bacteria or 293T cells, but not its catalytically inactive mutant C345A, decreased PTEN poly-ubiquitination by 64-70% in vitro (XREF_FIG).
On the other hand, ectopic expression of wild-type USP13, but not the C345A mutant which is still capable of interacting with PTEN (XREF_FIG), reduced the poly-ubiquitination of PTEN by 65% (XREF_FIG), suggesting that the enzymatic activity of USP13 is indispensable for USP13 dependent deubiquitination of PTEN.
Collectively, we nominate USP13 as a novel deubiquitinase which regulates MCL1 turnover in diverse solid tumors and propose that USP13 may be a potential therapeutic target for the treatment of various malignancies.
Two DUBs USP9X and USP13 deubiquitinate and stabilise MCL1, and hypomorphic mutations in both have been linked to neurodevelopmental disorders and neurodegenerative disease [XREF_BIBR, XREF_BIBR].
Moreover, beclin-1 and USP10 are involved in a potential feedforward mechanism in which beclin-1 stabilizes USP13, which in turn deubiquitinates and stabilizes USP10, leading to increased beclin-1 levels and activity.
Since USP13 can also deubiquitinate USP10, regulating the stability of USP13 by Beclin1 provides a mechanism for Beclin1 to control the stability of USP10.
These results suggest that USP13 may directly regulate the deubiquitination of USP10; however, USP10 may regulate USP13 indirectly perhaps by affecting the levels of Vps34 complexes.
Consistent with this possibility, the ubiquitination levels of USP10 were reduced when cells were cotransfected with an expression vector of USP13 and the addition of spautin-1 inhibited the deubiquitination of USP10 by USP13 (XREF_FIG).
The ubiquitination assay demonstrated that disruption of USP13 by shRNA markedly increased c-Myc ubiquitination and reduced c-Myc protein level in GSCs (XREF_FIG).
Furthermore, USP13 can deubiquitinate and stabilise ACLY and OGDH and c-Myc in ovarian cancer and glioblastoma, respectively, thereby functioning as an oncogene [XREF_BIBR, XREF_BIBR].
In this study, we demonstrate that the deubiquitinase USP13 stabilizes c-Myc by antagonizing FBXL14-mediated ubiquitination to maintain GSC self-renewal and tumorigenic potential.
More specifically, USP13 positively regulates the antiviral activity of IFNa against DEN-2 virus replication by deubiquitinating and stabilizing STAT1 (115) .
USP13, the main regulator of ovarian cancer energy metabolism, specifically deubiquitinates and stabilizes oxoglutarate dehydrogenase and ATP citrate lyase, which can catalyze fatty acid synthesis, glutaminolysis and mitochondrial respiration.
Furthermore, USP13 can deubiquitinate and stabilise ACLY and OGDH and c-Myc in ovarian cancer and glioblastoma, respectively, thereby functioning as an oncogene [XREF_BIBR, XREF_BIBR].
USP13, the main regulator of ovarian cancer energy metabolism, specifically deubiquitinates and stabilizes oxoglutarate dehydrogenase and ATP citrate lyase, which can catalyze fatty acid synthesis, glutaminolysis and mitochondrial respiration.
Furthermore, USP13 can deubiquitinate and stabilise ACLY and OGDH and c-Myc in ovarian cancer and glioblastoma, respectively, thereby functioning as an oncogene [XREF_BIBR, XREF_BIBR].
Besides phosphorylation, Siah2 activity can be modulated by the deubiquitinating enzyme USP13, which binds to and deubiquitinates Siah2, increasing its stability but diminishing its activity toward its substrates.
The DUB USP13 regulates Siah2 availability and activity as deubiquitination of Siah2 by USP13 results in a more stable, albeit less active, ubiquitin ligase.
Importantly, overexpression of USP13 together with FBXL14 abolished the increased c-Myc ubiquitination caused by FBXL14 overexpression (XREF_FIG, last lane).
Because ectopic overexpression of USP13 promoted deubiquitination of cohesin subunits, inactivation of USP13 was conversely expected to cause enhanced accumulation of ubiquitinated cohesin subunits.
Future studies are warranted to determine the ubiquitination of vinculin in 293T cell lines and whether USP13 deubiquitinates vinculin polyubiquitylation and stabilizes vinculin protein.
Consistently, overexpression of the wild type but not the USP13 mutant reduced c-Myc ubiquitination and resulted in elevated c-Myc protein levels (XREF_FIG).
Stabilization of IL-1R8/Sigirr by USP13 describes a novel anti-inflammatory pathway in diseases that could provide a new strategy to modulate immune activation.
On the other hand, ectopic expression of wild-type USP13, but not the C345A mutant which is still capable of interacting with PTEN (XREF_FIG), reduced the poly-ubiquitination of PTEN by 65% (XREF_FIG), suggesting that the enzymatic activity of USP13 is indispensable for USP13 dependent deubiquitination of PTEN.
To investigate whether USP13 mediated the deubiquitination of cohesin subunits, we cotransfected 293T cells with expression vectors for His ubiquitin and Myc-USP13, purified ubiquitinated proteins by Ni-NTA affinity chromatography, and performed Western blot with antibodies to SMC3 and RAD21 (XREF_FIG A).
The proper function of BAG6 seems to require the activity of the deubiquitinating enzyme USP13, which antagonizes gp78 mediated ubiquitination to ensure ERAD efficiency.
The C345A mutant of USP13 failed to reduce the ubiquitination of ACLY (XREF_FIG), suggesting that the deubiquitination activity is essential for the function of USP13.
As USP13 functions as a deubiquitinase that also interacts with c-Myc (XREF_FIG) and the preferential expression of USP13 in GSCs positively regulates c-Myc protein levels (XREF_FIG), we hypothesized that USP13 might mediate deubiquitination of c-Myc protein to prevent its degradation and stabilize c-Myc in GSCs.
Taken together, our results indicated that pharmacological inhibition of USP13 by spautin-1 reduced MCL1 protein abundance and increased tumor cell sensitivity to ABT-263.
We confirmed the siRNA screen results by transfecting each of the four oligos against USP13 into HEK293T cells, and indeed found that USP13 knockdown decreased the endogenous protein levels of MCL1, while modulating USP9X or OTUB2 with different siRNAs had no consistent effects on MCL1 expression.
Critically, treatment of USP13 depleted cells with the proteasome inhibitor MG132 rescued Mcl-1 protein levels, suggesting that USP13 protects Mcl-1 from proteasomal degradation.
In addition, we explored whether pharmacological inhibition of USP13 downregulated MCL1 protein expression and synergistically kill tumor cells in combination with ABT-263.
Interestingly, over-expression or depletion of USP13 did not modulate Mcl-1 expression in HPV- C33A cells, suggesting that Mcl-1 expression is not regulated by USP13 in these cells.
In addition, genetic depletion of USP13 using clustered regularly interspaced palindromic repeats (CRISPR)/Cas9, or pharmacological inhibition of USP13 by a small-molecule inhibitor spautin-1, markedly downregulates MCL1 protein expression and shows synergistic effects against tumor cells in combination with ABT-263, a selective antagonist of BCL-2 and BCL-XL.
Interestingly, although USP13 depletion reduced MCL1 protein levels, neither cell proliferation nor cell migration was significantly changed under normal growth conditions.
Consistent with USP13 removing ubiquitin from MCL1, wild type USP13, but not catalytically inactive mutant USP13 C345A, markedly reduced the amount of ubiquitinated MCL1.
Consistent with USP13 removing ubiquitin from MCL1, wild type USP13, but not catalytically inactive mutant USP13 C345A, markedly reduced the amount of ubiquitinated MCL1.
Hence, pharmaceutical intervention of USP13 activity is expected to antagonize the tumorigenic potential of MCL1 oncoprotein, and combined administration of USP13 inhibitors with clinically approved venetoclax therapy may represent a promising targeting strategy for the treatment of human cancer by inducing tumor cell death.
Results suggested that the overexpression of NF-kB p65 significantly decreased the expression levels of USP13 and PTEN, and re-introduction of USP13 rescued PTEN expression.
Although each of these five DUBs could interact with endogenous PTEN (XREF_SUPPLEMENTARY), only one of them, USP13, significantly increased endogenous PTEN protein expression (XREF_SUPPLEMENTARY).
Moreover, reintroduction of USP13 repressed the signaling transduction of NF-kB and largely rescued PTEN expression in NF-kB activated or miR-130b/301b overexpressed BC cells.
Collectively, these data suggest that loss of USP13 may contribute to loss of PTEN in a substantial fraction of human tumors, whereas in other tumors PTEN can be inactivated by different mechanisms, including genetic alterations and upregulation of PTEN ubiquitin ligases (such as NEDD4-1 14 and WWP2 15).
Knockdown of USP13 by USP13 shRNA, miR-130b/301b overexpression or NF-kB activation in BC cells leads to the loss of PTEN expression, which was subsequently demonstrated to be reversed by reintroduction of USP13.
Two independent USP13 shRNAs both decreased PTEN protein expression by 80% and increased phospho-AKT and phospho-FOXO1/3 levels by 3- to 5-fold in SUM159 breast cancer cells, while restoration of PTEN or expression of an RNAi resistant ' silence mutant ' (i.e., no amino acid change) of USP13 (USP13-RE) in USP13 depleted SUM159 cells completely reversed the effect of USP13 shRNA on upregulating the phosphorylation of AKT and FOXO (XREF_FIG and XREF_SUPPLEMENTARY).
Overexpression of miR-130b/301b or USP13 knockdown by shRNA delivery decreases USP13 expression, and further reduces PTEN protein expression and leads to enhancement of cell proliferation, invasion and migration.
Furthermore, USP13 overexpression induced phosphatase and tensin homolog deleted on chromosome 10 (PTEN) expression and repressed the activation of AKT as well as the expression of the downstream effectors glucose transporter-1 (GLUT1) and hexokinase-2 (HK2).
Treatment with afatinib alone diminished the number of proliferating cells to approximately 36%, while USP13 shRNA only slightly decreased cell proliferation.
By contrast, KD of USP13 only modestly reduced proliferation of cell lines with low USP13 expression (SKOV3 and IGROV1) (XREF_FIG; XREF_SUPPLEMENTARY).
In two other USP13 high HGSC cell lines (OAW28 and OVCAR3) XREF_BIBR, silencing USP13 also profoundly inhibited cell proliferation (XREF_SUPPLEMENTARY).
Next, we treated infected THP-1 cells with a cell-permeable potent autophagy inhibitor, spautin-1.58 Spautin-1 promotes the degradation of BECN1 by inhibiting 2 USPs (ubiquitin-specific peptidases), USP10 and USP13, which target BECN1.58 Spautin-1 treatment of infected cells significantly decreased E. chaffeensis proliferation (Fig. 3B).
As a results, downregulation of USP13 dramatically inhibited A549 and H226 cell proliferation by AKT and MAPK signaling and suppressed tumor growth in nude mice.
Overexpression of miR-130b/301b or USP13 knockdown by shRNA delivery decreases USP13 expression, and further reduces PTEN protein expression and leads to enhancement of cell proliferation, invasion and migration.
Loss of USP13 in breast cancer cells promotes AKT phosphorylation, cell proliferation, anchorage independent growth, glycolysis and tumor growth through downregulation of PTEN.
Loss of USP13 in breast cancer cells promotes AKT phosphorylation, cell proliferation, anchorage independent growth, glycolysis and tumour growth through downregulation of PTEN.
Overexpression of miR-130b/301b or USP13 knockdown by shRNA delivery decreases USP13 expression, and further reduces PTEN protein expression and leads to enhancement of cell proliferation, invasion and migration.
Interestingly, despite the fact that the viral oncogenes do not regulate USP13 expression, depletion of USP13 in HPV- C33A cells did not cause a proliferation defect.
Two independent USP13 shRNAs (XREF_FIG) both markedly increased the proliferation (XREF_FIG) and anchorage independent growth (XREF_FIG) of SUM159 breast cancer cells, while restoration of PTEN (XREF_FIG) or expression of an RNAi resistant USP13 mutant (XREF_SUPPLEMENTARY) completely reversed the effect of USP13 shRNA (XREF_FIG).
Stable knockdown (KD) of USP13 by lentiviral short hairpin RNAs (shRNAs) markedly inhibited the proliferation of the USP13 amplified cell lines (CAOV3 and HeyA8) and the USP13 overexpressing cell line (OVCAR8).
Next, USP13 knockdown prominently reduced the proliferation, epithelial-mesenchymal transition (EMT), migration, and invasion of Hep3B and Huh7 cells, while USP13 overexpression enhanced these biological behaviors of HepG2 and LO2 cells.
Collectively, these data demonstrate that the ubiquitination insensitive mutant of c-Myc is able to rescue the phenotypes caused by USP13 knockdown or FBXL14 overexpression in vitro and in vivo, which supports that USP13 and FBXL14 mediate posttranslational regulation of c-Myc to control the stem cell like phenotype and tumorigenic potential of GSCs.
We found a positive correlation between TRF1 levels and all the stem cell markers with the exception of MYC, although TRF1 was positively correlated with the MYC modulator USP13 (Fang et al., 2017).
CHX chase assays indicated that overexpression of WT-USP13, particularly a phosphomimetic USP13-Y708E, but not USP-Y708F, significantly up-regulated the half-time of the c-Myc protein in HEK293 cells (XREF_FIG).
In addition, IHC staining of Ki-67 and cleaved caspase 3 confirmed that USP13 disruption reduced c-Myc protein in the GSC derived xenografts and led to a significant decrease in cell proliferation and an increase in cell apoptosis within the tumor (not depicted).
As USP13 is a deubiquitinase, the interaction between USP13 and c-Myc led us to hypothesize that USP13 may stabilize c-Myc protein in GSCs through deubiquitination.
The expression of USP13-Y708E but not USP13 Y708F mutant significantly promoted the recruitment of c-Myc on the promoters of purine associated enzymes (XREF_FIG), consequently enhancing their expression (XREF_FIG).
As USP13 functions as a deubiquitinase that also interacts with c-Myc (XREF_FIG) and the preferential expression of USP13 in GSCs positively regulates c-Myc protein levels (XREF_FIG), we hypothesized that USP13 might mediate deubiquitination of c-Myc protein to prevent its degradation and stabilize c-Myc in GSCs.
In this study, we demonstrated that USP13 mediated deubiquitination and FBXL14 mediated ubiquitination regulate c-Myc protein levels in glioma cells and play a critical role in controlling the maintenance or differentiation of GSCs (XREF_FIG).
The ubiquitination assay demonstrated that disruption of USP13 by shRNA markedly increased c-Myc ubiquitination and reduced c-Myc protein level in GSCs (XREF_FIG).
In HCC cell lines, knockdown of USP13 by shRNAs markedly decreased HCC cell growth, and mechanistic investigations revealed that USP13 knockdown could markedly downregulate the expression levels of c-Myc.
Moreover, treatment with a proteasome inhibitor blocked the c-Myc loss caused by USP13 knockdown (not depicted), but overexpression of USP13 delayed c-Myc turnover in the presence of cycloheximide (not depicted), suggesting a critical role of USP13 in preventing proteasomal degradation of c-Myc in GSCs.
It is also noteworthy to point out that USP13 amplifications did not seem to increase B-cell infiltration in LUSC , which has the opposite effect on disease outcome [ 38 ] .
Next, USP13 knockdown prominently reduced the proliferation, epithelial-mesenchymal transition (EMT), migration, and invasion of Hep3B and Huh7 cells, while USP13 overexpression enhanced these biological behaviors of HepG2 and LO2 cells.
It is also noteworthy to point out that USP13 amplifications did not seem to increase B-cell infiltration in LUSC, which has the opposite effect on disease outcome [38].
On the other hand, although USP13 arm-level gains and high amplifications significantly increased lymphocyte infiltration in HNSC, OV and STAD, higher USP13 levels were correlated with shorter survival in ovarian and gastric cancers.
Overexpression of miR-130b/301b or USP13 knockdown by shRNA delivery decreases USP13 expression, and further reduces PTEN protein expression and leads to enhancement of cell proliferation, invasion and migration.
Results suggested that overexpression of NF-kB p65 greatly increased the number of migrated and invaded cells, however knockdown of miR-130b/301b or restoration of USP13 rescued the increased cell invasion and migration caused by NF-kB activation.
Overexpression of miR-130b/301b or USP13 knockdown by shRNA delivery decreases USP13 expression, and further reduces PTEN protein expression and leads to enhancement of cell proliferation, invasion and migration.
The in vivo experiments finally confirmed that USP13 dramatically repressed synovial hyperplasia, inflammatory cell infiltration, cartilage damage and bone loss in collagen induced arthritis (CIA) mice via the same molecular mechanisms detected in vitro.
Spautin-1 inhibits the activity of two ubiquitin specific peptidases, USP10 and USP13, causing an increase in proteasomal degradation of class III PI3 kinase complexes, which have been shown to regulate autophagy [XREF_BIBR].
Spautin-1 promotes the degradation of PIK3C3 (phosphatidylinositol 3-kinase catalytic subunit type 3, also termed Vps34 in yeast) complexes by inhibiting USP10 (ubiquitin specific peptidase 10) and USP13 (ubiquitin specific peptidase 13).
Indeed, a recent study showed that a small molecule, Spautin-1, promoted the degradation of Vps34 by inhibiting two ubiquitin specific proteases USP10 and USP13 that regulate the stability of the Vps34 complex [XREF_BIBR].
Spautin-1 inhibits ubiquitin specific peptidases, USP10 and USP13, and promotes the degradation of Vps34-PI3 kinase complexes, key regulators of autophagy, leading to inhibition of autophagy.
These data suggest that USP13-KD induces mitochondrial dysfunction and lipogenic dysfunction by reducing OGDH and ACLY activity, thereby reducing glutamine 's reductive carboxylation and glucose 's oxidation for lipid synthesis (XREF_FIG).
Depletion of USP13 markedly decreased protein stability of ACLY and OGDH (XREF_FIG; XREF_SUPPLEMENTARY), but had no effect on the transcription of ACLY and OGDH (XREF_FIG).
Overexpression of USP13 markedly reduced the levels of ubiquitinated ACLY and OGDH (XREF_FIG), suggesting that USP13 may stabilize ACLY and OGDH through deubiquitination.
We demonstrate that USP13 targeting leads to an increased sensitivity toward EGFR inhibition by both osimertinib and afatinib in NSCLC harboring the most common EGFR mutations (DeltaE746-A750 and L858R and T790M) while sparing EGFR wild-type cells and tumors.
Overall, we showed that USP13 abrogates sorting and degradation of ubiquitinated mutant EGFR, independent of its catalytic activity but requiring its UBA domains that are known to bind to K63-type ubiquitin chains preferentially.
38, 39 Given that USP13 targeting caused EGFR destabilization, some of the effects may be independent of the EGFR kinase activity as EGFR can suppress cell death in manners that are independent of its kinase activity.
Moreover, USP13 inhibition and silencing lead to a decreased half-life of the mutant EGFR protein in NSCLC cells, indicating that USP13 likely stabilizes EGFR.
Combined targeting of USP13 and EGFR strongly reduces the viability of EGFR mutant lung cancer cells in vitro and in vivo while sparing non malignant (EGFR wild-type) lung epithelial cells.
37 USP13 is likely to stabilize mutant EGFR in a ubiquitinated state, and inhibition of USP13 destabilizes mutant EGFR and abrogates signaling of mutant EGFR in lung cancer cells.
We found that USP13 inhibits mutant EGFR degradation by a process that leads to the accumulation of ubiquitinated (K48 and K63) EGFR, which is bound to c-Cbl and USP13.
USP13 downregulation with siRNA decreased the total protein levels of EGFR, indicating a clear connection between USP13 expression and EGFR protein levels.
USP13-KD also significantly decreased ACLY activity, while USP13 overexpression enhanced ACLY activity in the ACLY activity assay (XREF_SUPPLEMENTARY).
These data suggest that USP13-KD induces mitochondrial dysfunction and lipogenic dysfunction by reducing OGDH and ACLY activity, thereby reducing glutamine 's reductive carboxylation and glucose 's oxidation for lipid synthesis (XREF_FIG).
Depletion of USP13 markedly decreased protein stability of ACLY and OGDH (XREF_FIG; XREF_SUPPLEMENTARY), but had no effect on the transcription of ACLY and OGDH (XREF_FIG).
Overexpression of USP13 markedly reduced the levels of ubiquitinated ACLY and OGDH (XREF_FIG), suggesting that USP13 may stabilize ACLY and OGDH through deubiquitination.
Different forms of stress modulate these activities : hypoxia reduces USP13 expression enabling increased Siah2 activity, while cellular stress induces p38 activity and alters Siah localization, affec[MISSING/INVALID CREDENTIALS: limited to 200 char for Elsevier]
Different forms of stress modulate these activities : hypoxia reduces USP13 expression enabling increased Siah2 activity, while cellular stress induces p38 activity and alters Siah localization, affecting its recognition and targeting of substrates 174.
Indeed, knockdown of USP13 increased glucose uptake and glycolysis, which could be fully reversed by restoration of PTEN, as gauged by lactate production and glucose incorporation assays (XREF_FIG).
In this study, we identified USP13 as the first deubiquitinase that reverses PTEN poly-ubiquitination and stabilizes PTEN protein, and found that USP13 suppresses tumorigenesis and glycolysis through PTEN.
Loss of USP13 in breast cancer cells promotes AKT phosphorylation, cell proliferation, anchorage independent growth, glycolysis and tumor growth through downregulation of PTEN.
Loss of USP13 in breast cancer cells promotes AKT phosphorylation, cell proliferation, anchorage independent growth, glycolysis and tumour growth through downregulation of PTEN.
On the other hand, overexpression of the deubiquitinase USP13, which has been identified as a key regulator of MITF turnover, can enhance the basal half-life of the MITF protein to up to 4h (Zhao etal., 2011).
More recently, it was shown that MITF is targeted by the de-ubiquitinase USP13, a theoretically drug-able protease whose suppression results in strong downregulation of MITF protein levels.
By modulate the expression of MITF downstream genes, USP13 appeared to be essential for melanoma growth both in vivo and in vitro, indicating the possibility of targeting USP13 for melanoma therapy.
Moreover, treatment with a proteasome inhibitor blocked the c-Myc loss caused by USP13 knockdown (not depicted), but overexpression of USP13 delayed c-Myc turnover in the presence of cycloheximide (not depicted), suggesting a critical role of USP13 in preventing proteasomal degradation of c-Myc in GSCs.
Overexpression of miR-130b/301b or USP13 knockdown by shRNA delivery decreases USP13 expression, and further reduces PTEN protein expression and leads to enhancement of cell proliferation, invasion and migration.
Two independent USP13 shRNAs (XREF_FIG) both markedly increased the proliferation (XREF_FIG) and anchorage independent growth (XREF_FIG) of SUM159 breast cancer cells, while restoration of PTEN (XREF_FIG) or expression of an RNAi resistant USP13 mutant (XREF_SUPPLEMENTARY) completely reversed the effect of USP13 shRNA (XREF_FIG).
USP13 suppression induces apoptosis upon EGFR inhibition of mutant NSCLC cells USP13 downregulation or inhibition severely compromised the viability of PC9 and HCC827 cells when cotreated with afatinib .
In addition, terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick-end labeling (TUNEL) assay demonstrated that expression of the mutant c-Myc diminished the increased apoptosis caused by USP13 disruption in GSC derived xenografts (not depicted).
We then showed that over-expressing USP13 markedly suppressed inflammatory response, oxidative stress and apoptosis in H-FLSs upon IL-1beta or TNF-alpha challenge, whereas USP13 knockdown exhibited detrimental effects.
However, in the context of hypoxic or oxidative stresses, USP13 loss caused a substantial decrease of cell viability and a significant increase of cell apoptosis in both TOV-21G and SW-1573 tumor models.
The results indicate that USP13 promotes ECM expression by stabilizing Smad4 in lung fibroblasts and plays a role in the maintenance of the extracellular matrix in lungs.
The reductions in both protein levels and mRNA expression of ECM were observed in the isolated lung fibroblasts from USP13 deficient mice, suggesting that downregulation of USP13 reduces ECM levels through inhibiting its transcription.
The results indicate that USP13 promotes ECM expression by stabilizing Smad4 in lung fibroblasts and plays a role in the maintenance of the extracellular matrix in lungs .
Among the identified proteins, the vinculin protein level was upregulated by USP13 through an enzymatically mediated mechanism, which was confirmed by western blot analysis and RT-qPCR.
This molecule promotes the degradation of Vps34-PI 3 kinase complexes by inhibiting two ubiquitin specific peptidases, USP10 and USP13, that target the Beclin-1 subunit of Vps34 complexes.
Spautin-1, a potent small molecule, can promote the degradation of PI3KCIII and Vps34 complexes by inhibiting two ubiquitin specific peptidases, USP10 and USP13 which target the Beclin-1 subunit of Vp[MISSING/INVALID CREDENTIALS: limited to 200 char for Elsevier]
Spautin-1 has been recently reported to prevent autophagy by inhibiting the deubiquitinases USP10 and USP13, which leads to beclin 1 and Vps34 (or PI3KIII) degradation [XREF_BIBR].
Moreover, beclin-1 and USP10 are involved in a potential feedforward mechanism in which beclin-1 stabilizes USP13, which in turn deubiquitinates and stabilizes USP10, leading to increased beclin-1 levels and activity.
Indeed, knockdown of USP13 increased glucose uptake and glycolysis, which could be fully reversed by restoration of PTEN, as gauged by lactate production and glucose incorporation assays (XREF_FIG).
Functional studies demonstrated that overexpression of USP13 suppressed OSCC cell proliferation, glucose uptake and lactate production in vitro and inhibited tumor growth in vivo.
Furthermore, USP13 overexpression induced phosphatase and tensin homolog deleted on chromosome 10 (PTEN) expression and repressed the activation of AKT as well as the expression of the downstream effectors glucose transporter-1 (GLUT1) and hexokinase-2 (HK2).
Furthermore, USP13 overexpression induced phosphatase and tensin homolog deleted on chromosome 10 (PTEN) expression and repressed the activation of AKT as well as the expression of the downstream effectors glucose transporter-1 (GLUT1) and hexokinase-2 (HK2).
Using an imaging-based screen, Liu et al. (2011) recently identified a highly potent small molecule inhibitor of autophagy they named spautin-1 (specific and potent autophagy inhibitor 1), which promotes degradation of the Vps34 complexes via inhibiting ubiquitin-specific processing protease 10 (USP10) and USP13, two ubiquitin-specific peptidases that target the deubiquitination of Beclin1.2.
It is interesting to note that the knock-down of VPS34 and BECLIN 1 also causes the degradation of USP10 and USP13, which indicates the existence of a regulatory feedback loop [XREF_BIBR].
Another interesting observation made in the Spautin-1 study is that knock-down of VPS34 and Beclin 1 causes instability of USP10 and USP13, which indicates the existence of a regulatory feedback loop [XREF_BIBR].
The close functional interconnection between the central PI3K-III subunits and the DUBs is demonstrated by the interesting observation that knock-down of VPS34 and Beclin 1 causes instability of USP10 and USP13, which strongly indicates the existence of a regulatory feedback loop [XREF_BIBR].
The close functional interconnection between the central PI3K-III subunits and the DUBs is demonstrated by the interesting observation that knock-down of VPS34 and Beclin 1 causes instability of USP10 and USP13, which strongly indicates the existence of a regulatory feedback loop [XREF_BIBR].
Another interesting observation made in the Spautin-1 study is that knock-down of VPS34 and Beclin 1 causes instability of USP10 and USP13, which indicates the existence of a regulatory feedback loop [XREF_BIBR].
It is interesting to note that the knock-down of VPS34 and BECLIN 1 also causes the degradation of USP10 and USP13, which indicates the existence of a regulatory feedback loop [XREF_BIBR].
Because the accumulation of Bag6 * upon USP13 depletion is significantly reduced in cells co-depleted of USP13 and gp78 (XREF_FIG), we propose that USP13 is required to antagonize a promiscuous activity of gp78 towards Ubl4A, which would otherwise impair the function of the Bag6 complex by altering its interaction pattern and/or increasing its cleavage by a cellular protease.
In a cell study, USP5 and USP13 were found to degrade ubiquitin chains inside stress granules, defined as clumps of protein or RNA created when cells are stressed [XREF_BIBR].
Similar results were obtained in HCC827 cells ( Figure 2D ) , confirming that USP13 knockdown strongly enhances afatinib in treatment-naive lung cancer cell lines .
We found a positive correlation between TRF1 levels and all the stem cell markers with the exception of MYC, although TRF1 was positively correlated with the MYC modulator USP13 (Fang et al., 2017).
Notably, USP13 not only bound Bag6, but also interacted with MMS1 and alpha6, subunits of the proteasome (lane 5), further implicating USP13 in delivery pathways that targets substrates to the proteasome.
USP13 is upregulated in Alzheimer's disease (AD) and Parkinson's disease (PD), and USP13 knockdown via shRNA reduces neurotoxic proteins and increases proteasome activity in models of neurodegeneration.
USP13 knockdown significantly increased the activity of the 20S proteasome and reduced the levels of hyper-phosphorylated tau (p-tau) in primary cortical neurons.
Nonetheless, USP13 was not able to fully rescue the oncogenic function of NF-kB on BC cells, suggesting the possible involvement of other pathways in the process.
In vivo bioluminescent analysis confirmed that induced disruption of USP13 by doxycycline treatment significantly inhibited GSC tumor growth in mouse intracranial xenografts (XREF_FIG).
To further confirm the clinical relevance of targeting USP13 in established GBM tumors, we applied the Tet-on inducible knockdown system to examine whether inducible disruption of USP13 by doxycycline affects the growth of established xenograft tumors and animal survival.
Different forms of stress modulate these activities : hypoxia reduces USP13 expression enabling increased Siah2 activity, while cellular stress induces p38 activity and alters Siah localization, affec[MISSING/INVALID CREDENTIALS: limited to 200 char for Elsevier]
Different forms of stress modulate these activities : hypoxia reduces USP13 expression enabling increased Siah2 activity, while cellular stress induces p38 activity and alters Siah localization, affecting its recognition and targeting of substrates 174.
We then showed that over-expressing USP13 markedly suppressed inflammatory response, oxidative stress and apoptosis in H-FLSs upon IL-1beta or TNF-alpha challenge, whereas USP13 knockdown exhibited detrimental effects.
Our study provides a potential therapeutic strategy in which targeting USP13 blocks biosynthesis of metabolic intermediates and lipids thereby simultaneously inducing energy stress and cell death.
Similar to Beclin 1 knockdown, we found that suppression of the ubiquitin specific peptidase, USP10, or a small molecule inhibitor of the deubiquitinases USP10 and USP13, i.e., spautin-1 XREF_BIBR, can increase radiation induced DSBs and promote tumor cell death.
Our results demonstrate that USP13 is hijacked to maintain nsp13 expression and the inhibitory role of nsp13 in regulating type I IFN production , and USP13 inhibitor could be employed to suppress virus replication by targeting nsp13 for degradation thereby disrupting its inhibitory role in regulating type I IFN production .
Moreover , depletion of USP13 or treatment with USP13 inhibitor relieves the inhibitory role of nsp13 for type I IFN response and suppresses virus replication in host cells , suggesting that USP13 inhibitor could be employed to suppress virus replication by targeting nsp13 for degradation .
In vivo, the expression of WT-USP13, particularly USP13-Y708E construct in HCCC9810 cells, significantly enhanced the metastasis and growth of CCA cells, while the USP13-Y708F construct was resistant to carcinogenesis after implanting in nude mice (XREF_FIG).
Thus, several ubiquitin-conjugating E2 enzymes (UBE2L3, UBE2L5), the E3 ubiquitin ligases (TRIM21, TRIM38, ARIH2) and the ubiquitin specific protease or deconjugases (USP13) are 1.5-3.2-fold induced in the infected cells, while other E2, E3 enzymes and deconjugases (e.g.
However, in the context of hypoxic or oxidative stresses, USP13 loss caused a substantial decrease of cell viability and a significant increase of cell apoptosis in both TOV-21G and SW-1573 tumor models.
Since purified gp78 is insufficient to activate USP13 (Liu, Y unpublished results), further experiments using gp78 containing retrotranslocation complexes reconstituted in proteoliposome are required to elucidate how USP13 is regulated in the context of retrotranslocation.
Collectively, these results suggest that the second UBA in USP13 inhibits its DUB activity, but at the same time allows it to gain interaction with gp78.
Consistently, overexpression of wild type (WT), but not the catalytic-inactive (CA) mutant of USP13 with a mutation at the core enzymatic domain, could rescue the decreased nsp13 levels caused by USP13 depletion, suggesting that USP13 can regulate nsp13 levels most likely by deubiquitinating and consequently stabilizing nsp13.
Moreover, depletion of USP13 or treatment with USP13 inhibitor relieves the inhibitory role of nsp13 for type I IFN response and suppresses virus replication in host cells, suggesting that USP13 inhibitor could be employed to suppress virus replication by targeting nsp13 for degradation.
Functional studies demonstrated that overexpression of USP13 suppressed OSCC cell proliferation, glucose uptake and lactate production in vitro and inhibited tumor growth in vivo.
To investigate the effect of USP13 KD on glucose metabolism, we measured glycolytic capacity of OVCA cells when USP13 was knocked down and found that USP13 depletion significantly enhances lactate secretion in CAOV3 and HeyA8 cells, but it does not have a consistent effect on glucose uptake for CAOV3 and HeyA8 (XREF_SUPPLEMENTARY).
In line with our hypothesis, we found that USP13-KD significantly decreased M5 citrate, M3 fumarate and M3 malate pools in CAOV3 cells (XREF_FIG, top panel), whereas overexpression of USP13 had the opposite effect in SKOV3 cells (XREF_FIG, bottom panel).
We found that in both CAOV3 and HeyA8 cell lines, USP13-KD decreases the relative levels of M2 fumarate, malate and citrate, which are derived directly from [U- 13 C 6] glucose (XREF_FIG).
In line with our hypothesis, we found that USP13-KD significantly decreased M5 citrate, M3 fumarate and M3 malate pools in CAOV3 cells (XREF_FIG, top panel), whereas overexpression of USP13 had the opposite effect in SKOV3 cells (XREF_FIG, bottom panel).
USP13 specifically deubiquitinates and thus upregulates ATP citrate lyase and oxoglutarate dehydrogenase, two key enzymes that determine mitochondrial respiration, glutaminolysis and fatty acid synthesis.
This enhancement was dependent on USP13 deubiquitinase activity, as a catalytically inactive mutant of USP13 (USP13 C345A) failed to increase cell growth.
Cotargeting of EGFR and USP13 led to a robust increase in treatment efficacy both in vitro and in vivo, mainly due to a strong induction of apoptosis rather than enhancing the cell cycle arrest caused by afatinib alone.
In addition, reconstitution of WT USP13, but not the T196A mutant, fully rescued the foci formation of the BRCA1-A complex, DNA repair and cell cycle checkpoint in USP13 deficient cells and reversed hypersensitivity to cisplatin or olaparib induced by USP13 deficiency (XREF_FIG and XREF_SUPPLEMENTARY).
Because loss of USP13 phenocopies loss of VCP we hypothesize that USP13 functions in regulating the activity of the VCP complex itself and/or other ubiquitin ligases that promote TCRalphaGFP turnover.
Knockdown of USP13 by transiently transfecting with siUSP13 significantly potentiated expression of HSV-1-, but not SeV triggered expression of IFNB and TNFA in THP-1 cells (XREF_SUPPLEMENTARY).
Overexpression of USP13 increased FN and Smad4 protein levels in lung fibroblasts, while downregulation ofUSP13 reduced Smad4 protein levels, without altering Smad4 mRNA expression, suggesting that USP13 regulates Smad4 protein stability.
While A20 inhibits PtdIns3P signaling by removing the TRAF6 dependent Lys63 linked chains from Beclin 1, the enzymes USP10 and USP13 prevent PI3K and III complex components from their degradation and, therefore, support autophagy.
An inhibitor of USP13 decreased the K63 polyubiquitination on TRAF6 , TAK1 phosphorylation , IL-1beta , and TNF-alpha induction in response to LPS in BMDMs .
Knockdown of USP13 by transiently transfecting with siUSP13 significantly potentiated expression of HSV-1-, but not SeV triggered expression of IFNB and TNFA in THP-1 cells (XREF_SUPPLEMENTARY).
S4a, nsp13 overexpression led to decrease of IFN-beta levels, and loss of USP13 can reverse the decrease of IFN-beta levels caused by nsp13 overexpression.
Overexpression of USP13 increased FN and Smad4 protein levels in lung fibroblasts, while downregulation ofUSP13 reduced Smad4 protein levels, without altering Smad4 mRNA expression, suggesting that USP13 regulates Smad4 protein stability.
We further report that genetic or pharmacological inhibition of USP13 considerably reduces MCL1 protein abundance and significantly increases tumor cell sensitivity to BH3 mimetic inhibitors targeting BCL-2 and BCL-XL.
We further report that genetic or pharmacological inhibition of USP13 considerably reduces MCL1 protein abundance and significantly increases tumor cell sensitivity to BH3 mimetic inhibitors targeting BCL-2 and BCL-XL.
We further report that genetic or pharmacological inhibition of USP13 considerably reduces MCL1 protein abundance and significantly increases tumor cell sensitivity to BH3 mimetic inhibitors targeting BCL-2 and BCL-XL.
We further report that genetic or pharmacological inhibition of USP13 considerably reduces MCL1 protein abundance and significantly increases tumor cell sensitivity to BH3 mimetic inhibitors targeting BCL-2 and BCL-XL.
USP13 specifically deubiquitinates and thus upregulates ATP citrate lyase and oxoglutarate dehydrogenase, two key enzymes that determine mitochondrial respiration, glutaminolysis and fatty acid synthesis.
For example, 3 proteins that regulate ubiqutination state were modulated by SAHA : E3 ubiqutin ligase DTX3L, E2 ubiquting cojugating enzyme UBE2H, and a deubiquitinase USP13.
Another autophagy inhibitor, spautin-1, degrades class III PI3K by inhibiting the activity of the ubiquitin specific peptidases, USP10 and USP13 (Mateo et al., 2013, Liu et al., 2011).
Overexpression of USP13 inhibited wild-type and K63R mutant forms of ubiquitin associated ubiquitination of ACLY, but had no effect on the K48R ubiquitin associated ubiquitination (XREF_FIG).
Furthermore, we found that USP13-KD decreased the level of M4 TCA cycle metabolites, which are directly derived from [U- 13 C 5] glutamine, indicating a reduced flux of glutamine into TCA cycle (XREF_SUPPLEMENTARY).
Furthermore, high USP13 expression enhances the replication stress response, promotes cancer cell chemoresistance, and is correlated with poor prognosis of cancer patients.
USP13 functions as a ubiquitin specific enzyme by cleaving the K48 linked polyubiquitin chain off protein substrate to reverse ubiquitin mediated protein degradation.
Unfortunately, the rescue analysis showed that re-expression of HA-USP13 was not sufficient to reverse the reduction of pATM in RAP80 depleted EC cells, leading us to think that there are some other E3 ligases or DUB enzymes involved in mediating the regulation of RAP80 on the degradation of pATM.
In addition, reconstitution of WT USP13, but not the T196A mutant, fully rescued the foci formation of the BRCA1-A complex, DNA repair and cell cycle checkpoint in USP13 deficient cells and reversed hypersensitivity to cisplatin or olaparib induced by USP13 deficiency (XREF_FIG and XREF_SUPPLEMENTARY).
USP13 specifically deubiquitinates and thus upregulates ATP citrate lyase and oxoglutarate dehydrogenase, two key enzymes that determine mitochondrial respiration, glutaminolysis and fatty acid synthesis.
Moreover, USP13 knockout or knockdown did not seem to disrupt the mitochondrial homeostasis, in which an amino-terminally truncated isoform of MCL1 has been implicated 39.
In addition, reconstitution of WT USP13, but not the T196A mutant, fully rescued the foci formation of the BRCA1-A complex, DNA repair and cell cycle checkpoint in USP13 deficient cells and reversed hypersensitivity to cisplatin or olaparib induced by USP13 deficiency (XREF_FIG and XREF_SUPPLEMENTARY).
Functionally, overexpression of USP13 and FBXL14 together in GSCs abolished the enhanced cell differentiation induced by FBXL14 overexpression (not depicted), and knockdown of FBXL14 and USP13 together in GSCs attenuated the increased differentiation induced by USP13 disruption (not depicted).
Because the reductions in the levels of USP10 and USP13 in H4-LC3-GFP cells treated with spautin-1 appeared later than the reductions in the levels of Vps34 complexes and autophagy (XREF_FIG), the reduced levels of USP10 and USP13 are unlikely to be the primary reason for the ability of spautin-1 to reduce the levels of PtdIns3P and inhibit autophagy.
Inhibition of USP13 simultaneously suppresses glutamate anaplerosis to refill the TCA cycle and the generation of acetyl-CoA, a vital building block for de novo biosynthesis of fatty acids, leading to the marked supersession of OVCA cell proliferation and tumourigenic potential.
It will be interesting to elucidate if the stability of the other PI3K and III complex members is also affected, as in the case of Spautin-1 -- mediated inhibition of USP10 and USP13 [XREF_BIBR] and if the control of Beclin 1 stability is mediated by HSP90 in general or whether this represents a regulatory event specifically developed in phagocytic cells.
Overexpression of USP13 increased FN and Smad4 protein levels in lung fibroblasts , while downregulation of USP13 reduced Smad4 protein levels , without altering Smad4 mRNA expression , suggesting that USP13 regulates Smad4 protein stability .
Ectopic overexpression of USP13 significantly decreased the levels of endogenous ubiquitinated SMC3 and RAD21, indicating that USP13 can function as a deubiquitinase for cohesin subunits.
Exceptional PD related examples of seemingly active miRNA spliced transcripts predicted interactions include USP13, which promotes smooth (SMO) signaling by preventing its ubiquitination, RGS3 which contributes to neural progenitor and stem cell regulation and MGAT1, involved in multiple sclerosis.
Ectopic overexpression of USP13 significantly decreased the levels of endogenous ubiquitinated SMC3 and RAD21, indicating that USP13 can function as a deubiquitinase for cohesin subunits.
Exceptional PD related examples of seemingly active miRNA spliced transcripts predicted interactions include USP13, which promotes smooth (SMO) signaling by preventing its ubiquitination, RGS3 which contributes to neural progenitor and stem cell regulation and MGAT1, involved in multiple sclerosis.
In line with our hypothesis, we found that USP13-KD significantly decreased M5 citrate, M3 fumarate and M3 malate pools in CAOV3 cells (XREF_FIG, top panel), whereas overexpression of USP13 had the opposite effect in SKOV3 cells (XREF_FIG, bottom panel).
Importantly, USP13 knockdown specifically reduced the 250 kD Bag6-SGTA crosslinking product without affecting either the SGTA dimer or other SGTA containing crosslinking products (XREF_FIG).
While overexpression of USP13 inhibits virus triggered induction of downstream genes, knockdown of USP13 or USP13 deficiency potentiates DNA virus triggered activation of IRF3 and expression of type I IFNs and proinflammatory cytokines.
Furthermore, USP13 overexpression induced phosphatase and tensin homolog deleted on chromosome 10 (PTEN) expression and repressed the activation of AKT as well as the expression of the downstream effectors glucose transporter-1 (GLUT1) and hexokinase-2 (HK2).
In addition, reconstitution of WT USP13, but not the T196A mutant, fully rescued the foci formation of the BRCA1-A complex, DNA repair and cell cycle checkpoint in USP13 deficient cells and reversed hypersensitivity to cisplatin or olaparib induced by USP13 deficiency (XREF_FIG and XREF_SUPPLEMENTARY).
In response to DNA damage, USP13 is phosphorylated by ATM, which in turn facilitates USP13 recruitment to DSBs, RAP80 deubiquitination, and triggers DDR signalling.
USP13 specifically deubiquitinates and thus upregulates ATP citrate lyase and oxoglutarate dehydrogenase, two key enzymes that determine mitochondrial respiration, glutaminolysis and fatty acid synthesis.
In line with our hypothesis, we found that USP13-KD significantly decreased M5 citrate, M3 fumarate and M3 malate pools in CAOV3 cells (XREF_FIG, top panel), whereas overexpression of USP13 had the opposite effect in SKOV3 cells (XREF_FIG, bottom panel).
Expression of USP13 (but not the C345A mutant) in MDA-MB-231 cells, which led to upregulation of PTEN and downregulation of phospho-AKT and phospho-FOXO1/3 (XREF_FIG), significantly inhibited cell proliferation (XREF_FIG), colony formation on soft agar (XREF_FIG), lactate production (XREF_FIG), glucose uptake (XREF_FIG) and tumor growth (XREF_FIG), while knockdown of PTEN (XREF_SUPPLEMENTARY) rescued the proliferation of USP13 overexpressing MDA-MB-231 cells (XREF_FIG).
When expressed alone , neither oncogene increased USP13 expression ; co-expression of both E6 and E7 led to a small , but non-significant , increase in USP13 expression .
A recent study identified a role of USP13 in VPS34 deubiquitination and stabilization and NEDD4-1 autoubiquitination promotes the recruitment of USP13 to VPS34 35.
More importantly, USP13 deficiency resulted in impaired melanoma growth both in vitro and in vivo, and reintroduction of MITF reversed the inhibitory effect of USP13, demonstrating that MITF contributed to melanoma progression under the ubiquitination modification of USP13 95.