Figure 2 - uploaded by René H Medema
Content may be subject to copyright.
Usp39 contains a Dub-domain, but is catalytically inactive. (A) Sequence alignment of the regions flanking the residues of the catalytic triad of the indicated Dubs; the cysteine at position 234 is replaced by an aspartic acid, histidine at position 513 by serine and the aspartic acid of position 530 by a glutamine. (B) The in vitro enzymatic activity of USP4, Usp8 and Usp39 were assayed using Ub-AMC as a substrate. The concentration of each protein was 10 nM.
Source publication
Accurate chromosome segregation relies on the mitotic spindle checkpoint. This checkpoint acts to restrict ubiquitin ligase activity of the Anaphase-promoting complex (APC/C) in mitosis until all chromosomes are bipolarly attached to the mitotic spindle. We performed a functional RNAi-based screen to identify De-ubiquitinating enzymes (Dubs) involv...
Contexts in source publication
Context 1
... activity has only been tested for a subset of the Dubs. In case of Usp39, protease activity has not been assessed thus far. Although Usp39 harbors a Dub-domain, the three important active-site residues (a cysteine, histidine and aspartic acid) are not conserved in Usp39, suggesting that this Dub-family member may not act as an actual Dub-enzyme ( Fig. 2A). Indeed, in vitro activity-analysis of the catalytic domain of Usp39 towards Ubiquitin C-terminal 7-amido-4-methylcoumarin (Ub-AMC) confirmed the absence of Dub-activity (Fig. 2B). Comparison of protease-activity of different Dub-domains showed that the catalytic domains of Usp4 and Usp8, containing all three catalytic residues, are ...
Context 2
... active-site residues (a cysteine, histidine and aspartic acid) are not conserved in Usp39, suggesting that this Dub-family member may not act as an actual Dub-enzyme ( Fig. 2A). Indeed, in vitro activity-analysis of the catalytic domain of Usp39 towards Ubiquitin C-terminal 7-amido-4-methylcoumarin (Ub-AMC) confirmed the absence of Dub-activity (Fig. 2B). Comparison of protease-activity of different Dub-domains showed that the catalytic domains of Usp4 and Usp8, containing all three catalytic residues, are active, whereas the Dub-domain of Usp39, as shown in Figure 2B lacks enzymatic activity. Altogether, these data show the absence of catalytic activity of Usp39 in vitro and suggest ...
Context 3
... in vitro activity-analysis of the catalytic domain of Usp39 towards Ubiquitin C-terminal 7-amido-4-methylcoumarin (Ub-AMC) confirmed the absence of Dub-activity (Fig. 2B). Comparison of protease-activity of different Dub-domains showed that the catalytic domains of Usp4 and Usp8, containing all three catalytic residues, are active, whereas the Dub-domain of Usp39, as shown in Figure 2B lacks enzymatic activity. Altogether, these data show the absence of catalytic activity of Usp39 in vitro and suggest Usp39 to be incapable of cleaving ubiquitin in vivo. ...
Similar publications
Defects in meiotic spindle structure contribute to chromosome segregation errors leading to genomic instability in oocytes and embryos upon fertilization. In this study, we analyzed the mechanisms that control spindle microtubule nucleation and stability in mammalian oocytes, and identified NEDD1/GCP-WD as a key regulator. NEDD1 specifically co-loc...
Monopolar spindle 1 (Mps1) is essential for the spindle assembly checkpoint (SAC), which prevents anaphase onset in the presence of misaligned chromosomes. Moreover, Mps1 kinase contributes in a SAC-independent manner to the correction of erroneous initial attachments of chromosomes to the spindle. Our characterization of the Drosophila homologue r...
In contrast to many eukaryotic organisms in which kinetochores are assembled on localized centromeres of monocentric chromosomes, Caenorhabditis elegans has diffuse kinetochores, termed holo-kinetochores, which are assembled along the entire length of the mitotic chromosome. Despite this cytologically distinct chromosomal architecture, holo-kinetoc...
Evidence that Aurora B is implicated in spindle checkpoint signalling independently of error correction This is an open-access article distributed under the terms of the Creative Commons Attribution Noncommercial No Derivative Works 3.0 Unported License, which permits distribution and reproduction in any medium, provided the original author and sou...
Genetic mutations in the mitotic regulatory kinase BUBR1 are associated with the cancer-susceptible disorder mosaic variegated aneuploidy (MVA). In patients with biallelic mutations, a missense mutation pairs with a truncating mutation. Here, we show that cell lines derived from MVA patients with biallelic mutations have an impaired mitotic checkpo...
Citations
... 6 In addition to being a member of this family of more than 50 USPs, USP39 is also an important component of the spliceosomal complex 25S U4/U6.U5 tri-snRNP, which plays an important role in RNA splicing. 7,8 In recent years, carcinogenic effects of USP39 have been reported in many cancer types. It has been reported that USP39 is downregulated in lung cancer. ...
Objective: Ubiquitin-specific peptidase 39 (USP39) plays a carcinogenic role in many cancers, but little research has been conducted examining whether it is involved in head and neck squamous cell carcinoma (HNSCC). Therefore, this study explored the functional role of USP39 in HNSCC. Method: Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to identify differentially expressed proteins (DEPs) between the HNSCC tumor and adjacent healthy tissues. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were used to assess the functional enrichment of DEPs. Immunohistochemistry was used to detect protein expression. The viability and migration of two HNSCC cell lines, namely CAL27 and SCC25, were detected using the cell counting kit-8 assay and a wound healing assay, respectively. Quantitative real-time PCR was used to detect the expression level of signal transducer and activator of transcription 1 (STAT1) mRNA. Results: LC-MS/MS results identified 590 DEPs between HNSCC and adjacent tissues collected from 4 patients. Through GO and KEGG pathway analyses, 34 different proteins were found to be enriched in the spliceosome pathway. The expression levels of USP39 and STAT1 were significantly higher in HNSCC tumor tissue than in adjacent healthy tissue as assessed by LC-MS/MS analysis, and the increased expression of USP39 and STAT1 protein was confirmed by immunohistochemistry in clinical samples collected from 7 additional patients with HNSCC. Knockdown of USP39 or STAT1 inhibited the viability and migration of CAL27 and SCC25 cells. In addition, USP39 knockdown inhibited the expression of STAT1 mRNA in these cells. Conclusion: Our findings indicated that USP39 knockdown may inhibit HNSCC viability and migration by suppressing STAT1 expression. The results of this study suggest that USP39 may be a potential new target for HNSCC clinical therapy or a new biomarker for HNSCC.
... Additionally, its N-terminal ZnF domain is incapable of binding ubiquitin. Therefore, it was originally thought that USP39, like its yeast orthologue Sad1, are deprived of this catalytic function (Van Leuken et al., 2008;Hadjivassiliou et al., 2014). However, recent studies have introduced the intriguing possibility that USP39 and Sad1 might retain the ability to detach ubiquitin chains from substrates, even though the conventional cysteine residue in their catalytic triads is replaced with an aspartic acid. ...
... However, the precise molecular mechanisms by which they manage this recruitment are not yet fully understood. Nevertheless, USP39 is indispensable for the splicing of a wide array of mRNAs, including those for Aurora kinase B (Van Leuken et al., 2008) and various autophagy-related genes , thereby playing a significant role in a multitude of cellular processes. Furthermore, it has been demonstrated that USP39 specifically influences immunoglobin gene rearrangement through a mechanism that depends on the spliceosome but is independent of RNA splicing. ...
Proteases that cleave ubiquitin or ubiquitin-like proteins (UBLs) are critical players in maintaining the homeostasis of the organism. Concordantly, their dysregulation has been directly linked to various diseases, including cancer, neurodegeneration, developmental aberrations, cardiac disorders and inflammation. Given their potential as novel therapeutic targets, it is essential to fully understand their mechanisms of action. Traditionally, observed effects resulting from deficiencies in deubiquitinases (DUBs) and UBL proteases have often been attributed to the misregulation of substrate modification by ubiquitin or UBLs. Therefore, much research has focused on understanding the catalytic activities of these proteins. However, this view has overlooked the possibility that DUBs and UBL proteases might also have significant non-catalytic functions, which are more prevalent than previously believed and urgently require further investigation. Moreover, multiple examples have shown that either selective loss of only the protease activity or complete absence of these proteins can have different functional and physiological consequences. Furthermore, DUBs and UBL proteases have been shown to often contain domains or binding motifs that not only modulate their catalytic activity but can also mediate entirely different functions. This review aims to shed light on the non-catalytic, moonlighting functions of DUBs and UBL proteases, which extend beyond the hydrolysis of ubiquitin and UBL chains and are just beginning to emerge.
... Usp39 (Inactive Ubiquitin-Specific Peptidase 39) is also called U4/ U6. U5 tri-snRNP associated protein 2, and shares 65% amino acid identity with yeast Sad1 11 . Usp39 is not required for the stability of the U4/U6. ...
... Nevertheless, a previous study demonstrated that Usp39 is essential for the recruitment of the tri-snRNP to the pre-spliceosome and for the splicing function 26 . In addition, Usp39 has been shown to be involved in splicing of Aurora B which is essential for proper spindle checkpoint function 11 . Our study provides strong evidence that Usp39 plays an important role in splicing regulation. ...
Regulation of alternative splicing (AS) enables a single transcript to yield multiple isoforms that increase transcriptome and proteome diversity. Here, we report that spliceosome component Usp39 plays a role in the regulation of hepatocyte lipid homeostasis. We demonstrate that Usp39 expression is downregulated in hepatic tissues of non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) subjects. Hepatocyte-specific Usp39 deletion in mice leads to increased lipid accumulation, spontaneous steatosis and impaired autophagy. Combined analysis of RNA immunoprecipitation (RIP-seq) and bulk RNA sequencing (RNA-seq) data reveals that Usp39 regulates AS of several autophagy-related genes. In particular, deletion of Usp39 results in alternative 5’ splice site selection of exon 6 in Heat shock transcription factor 1 (Hsf1) and consequently its reduced expression. Importantly, overexpression of Hsf1 could attenuate lipid accumulation caused by Usp39 deficiency. Taken together, our findings indicate that Usp39-mediated AS is required for sustaining autophagy and lipid homeostasis in the liver.
... USP39 has been traditionally considered an inactive DUB due to the substitution of the conserved cysteine residue at amino acid 234 in its USP domain with aspartate [30][31][32]. As a result, the deubiquitinase-independent functions of USP39, particularly its role as a splicing factor in pre-mRNA splicing, have been extensively studied [27,[33][34][35][36][37]. ...
ETS2 is a member of the ETS family of transcription factors and has been implicated in the regulation of cell proliferation, differentiation, apoptosis, and tumorigenesis. The aberrant activation of ETS2 is associated with various human cancers, highlighting its importance as a therapeutic target. Understanding the regulatory mechanisms and interacting partners of ETS2 is crucial for elucidating its precise role in cellular processes and developing novel strategies to modulate its activity. In this study, we conducted binding assays using a human deubiquitinase (DUB) library and identified USP39 as a novel ETS2-binding DUB. USP39 interacts with ETS2 through their respective amino-terminal regions, and the zinc finger and PNT domains are not required for this binding. USP39 deubiquitinates ETS2 without affecting its protein stability. Interestingly, however, USP39 significantly suppresses the transcriptional activity of ETS2. Furthermore, we demonstrated that USP39 leads to a reduction in the nuclear localization of ETS2. Our findings provide valuable insights into the intricate regulatory mechanisms governing ETS2 function. Understanding the interplay between USP39 and ETS2 may have implications for therapeutic interventions targeting ETS2-related diseases, including cancer, where the dysregulation of ETS2 is frequently observed.
... Increasing evidence have shown that USP39 acted as an RNA splicing factor to participate in the development of normal cells or tumor cells [12,[20][21][22]. In this study, we also detected whether the Cyclin B1 mRNA maturation could be affected by the USP39 expression. ...
Background:
The elevated Cyclin B1 expression contributes to various tumorigenesis and poor prognosis. Cyclin B1 expression could be regulated by ubiquitination and deubiquitination. However, the mechanism of how Cyclin B1 is deubiquitinated and its roles in human glioma remain unclear.
Methods:
Co-immunoprecipitation and other assays were performed to detect the interacting of Cyclin B1 and USP39. A series of in vitro and in vivo experiments were performed to investigate the effect of USP39 on the tumorigenicity of tumor cells.
Results:
USP39 interacts with Cyclin B1 and stabilizes its expression by deubiquitinating Cyclin B1. Notably, USP39 cleaves the K29-linked polyubiquitin chain on Cyclin B1 at Lys242. Additionally, overexpression of Cyclin B1 rescues the arrested cell cycle at G2/M transition and the suppressed proliferation of glioma cells caused by USP39 knockdown in vitro. Furthermore, USP39 promotes the growth of glioma xenograft in subcutaneous and in situ of nude mice. Finally, in human tumor specimens, the expression levels of USP39 and Cyclin B1 are positively relevant.
Conclusion:
Our data support the evidence that USP39 acts a novel deubiquitinating enzyme of Cyclin B1 and promoted tumor cell proliferation at least in part through Cyclin B1 stabilization, represents a promising therapeutic strategy for tumor patients.
... It was once thought that USP39 has no DUB activity due to the lack of conserved active sites (cysteine, histidine, and aspartic acid) in the deubiquitinating domain [15]. However, subsequent studies have proved that USP39 could regulate the stability of DNA damage-related protein CHK2 [16], stabilize SP1 and prolong its half-life period [17], or stabilize STAT1 in the type I IFN signaling pathway thereby promoting innate antiviral immunity through its deubiquitinating function [18]. ...
Ubiquitin-specific protease 39(USP39) plays an important role in modulating pre-mRNA splicing and ubiquitin-proteasome dependent proteolysis as a member of conserved deubiquitylation family. Accumulating evidences prove that USP39 participates in the development of hepatocellular carcinoma (HCC). However, little is known about the mechanism especially deubiquitinating target of USP39 in regulating hepatocellular carcinoma (HCC) growth. Here, we prove that USP39 promotes HCC cell proliferation and migration by directly deubiquitin β-catenin, a key molecular of Wnt/β-catenin signaling pathway whose abnormal expression or activation results in several tumors, following its co-localization with USP39. In this process, the expression of E3 ligase TRIM26, which is proved to restrain HCC in our previous research, shows a decreasing trend. We further demonstrate that TRIM26 pre-mRNA splicing and maturation is inhibited by USP39, accompanied by its reduction of ubiquitinating β-catenin, facilitating HCC progression indirectly. In summary, our data reveal a novel mechanism in the progress of HCC that USP39 promotes the proliferation and migration of HCC through increasing β-catenin level via both direct deubiquitination and reducing TRIM26 pre-mRNA maturation and splicing, which may provide a new idea and target for clinical treatment of HCC.
... Ubiquitin-specific protease 39 (USP39), as a deubiquitinating enzyme, has only been reported on a few times with regard to deubiquitination in this context (1619). Although USP39 belongs to a member of the deubiquitinating family, the conventional active site for deubiquitination is absent (20), yet it has been shown to be expressed highly in the nucleus and to play an important role in the splicing of mature mRNA (21). In the early days, USP39 was thought to exclusively function as a splicing factor; however, increasing evidence has demonstrated that USP39 also performs deubiquitination functions. ...
IκBα is a critical protein that inhibits NF-κB nuclear translocation and impairs NF-κB–mediated signaling. The abundance of IκBα determines the activation and restoration of the inflammatory response. However, posttranslational regulation of IκBα remains to be fully understood. In this study, we identified ubiquitin-specific protease 39 (USP39) as a negative regulator in the NF-κB inflammatory response by stabilizing basal IκBα. The expression of USP39 in macrophages was reduced under LPS-induced inflammation. Knockdown or knockout of USP39 in macrophages significantly increased the expression and secretion of proinflammatory cytokines upon exposure to LPS or Escherichia coli, whereas reexpression of exogenous USP39 in USP39-deficient macrophages rescued the effect. Moreover, USP39-defective mice were more sensitive to LPS or E. coli–induced systemic sepsis. Mechanistically, USP39 interacted with and stabilized IκBα by reducing K48-linked polyubiquination of IκBα. Taken together, to our knowledge, our study for the first time revealed the inhibitory function of USP39 in the NF-κB inflammatory response, providing a previously unknown mechanism for control of inflammatory cytokine induction in the cellular anti-inflammatory response.
... Although USP39 was initially identified as a DUB without ubiquitin hydrolysis activity, other studies have suggested that it plays a role in RNA splicing and oncogenesis in multiple malignant tumors [157,158]. Intriguingly, USP39 stabilizes SP1, ZEB1, and FOXM1 through its deubiquitination activity, thus supporting the progression of hepatocellular carcinoma and breast cancer [159][160][161]. Silencing USP39 expression hinders MGC-803 GC cell proliferation and induces G2/M arrest and PARP cleavage [60]. ...
Gastric cancers (GCs) are malignant tumors with a high incidence that threaten global public health. Despite advances in GC diagnosis and treatment, the prognosis remains poor. Therefore, the mechanisms underlying GC progression need to be identified to develop prognostic biomarkers and therapeutic targets. Ubiquitination, a post-translational modification that regulates the stability, activity, localization, and interactions of target proteins, can be reversed by deubiquitinases (DUBs), which can remove ubiquitin monomers or polymers from modified proteins. The dysfunction of DUBs has been closely linked to tumorigenesis in various cancer types, and targeting certain DUBs may provide a potential option for cancer therapy. Multiple DUBs have been demonstrated to function as oncogenes or tumor suppressors in GC. In this review, we summarize the DUBs involved in GC and their associated upstream regulation and downstream mechanisms and present the benefits of targeting DUBs for GC treatment, which could provide new insights for GC diagnosis and therapy.
... Inactive Ubiquitin-Speci c Peptidase 39 (Usp39) is also called U4/U6. U5 tri-snRNP associated protein 2, and shares 65% amino acid identity with yeast Sad1 (15). Usp39 is not required for the stability of the U4/U6. ...
... Nevertheless, a previous study demonstrated that Usp39 is essential for the recruitment of the tri-snRNP to the pre-spliceosome and for the splicing function (27). In addition, Usp39 has been shown to be involved in splicing of Aurora B which is essential for proper spindle checkpoint function (15). Our study provides strong evidence that Usp39 plays an important role in splicing regulation. ...
Regulation of alternative splicing (AS) enables a single transcript to yield multiple isoforms that increase transcriptome and proteome diversity. Here, we report that spliceosome component Usp39 plays a critical role in the regulation of hepatocyte lipid homeostasis. We demonstrate that Usp39 expression is downregulated in hepatic tissues of NAFLD and non-alcoholic steatohepatitis (NASH) subjects. Hepatocyte-specific Usp39 deletion leads to increased lipid accumulation, spontaneous steatosis and impaired autophagy. Combined analysis of RIP-seq and RNA-seq data reveals that Usp39 regulates AS of several autophagy-related genes. For example, deletion of Usp39 results in alternative 5’ splice site selection of exon 6 in Heat shock transcription factor 1 ( Hsf1 ) and consequently reduced expression. Importantly, overexpression of Hsf1 restores attenuated lipid accumulation caused by Usp39 deficiency. Taken together, our findings indicate that Usp39-mediated AS is crucial for sustaining lipophagy and lipid homeostasis in the liver.
... Ubiquitin-specific protease 39 (USP39) belongs to the deubiquitination enzyme family [5]. It has previously been reported that USP39 regulates cell division and mRNA splicing [6][7][8]). Therefore, for tumor cells, the development of tumor cells can be inhibited by regulating their growth and reproduction. ...
... Recently, studies have shown that USP39 is differentially expressed in lung cancer cells and is related to the development and progression of lung cancer cells and can promote the occurrence and development of tumor cells. For example, Yuan et al. [13] found that USP39 is upregulated in NSCLC tissues, and USP39 knockout can inhibit the growth 8 Disease Markers and metastasis of NSCLC cells. However, the mechanism by which USP39 participates in NSCLC cell proliferation needs further research. ...
It is known that miR-381 plays a therapeutic role in a variety of cancers, but the regulatory mechanism of miR-381 in the treatment of lung cancer remains unclear. This study is aimed at exploring the expression level and mechanism of miR-381 in lung cancer. In this experiment, quantitative real-time PCR (qRT-PCR), western blot, and other methods were used to detect the expression of miR-381 and ubiquitin-specific protease 39 (USP39) in lung cancer tissues. The target genes of miR-381 were predicted by bioinformatics techniques, and the targeting relationship between miR-381 and USP39 was verified by the dual-luciferase reporting method. The expression levels of miR-381 and USP39 were adjusted to verify the effect of miR-381 on the expression of USP39 gene. The effect of miR-381 expression on proliferation of lung cancer cells was verified by cell proliferation and invasion experiments. miR-381 was downregulated in non-small-cell lung cancer tissues and cell lines, while USP39 was upregulated. The dual-luciferase reporter gene assay showed that miR-381 and USP39 had targeted binding sites. After transfection with miR-381 mimics, USP39 expression was significantly decreased, cell proliferation decreased, and apoptosis increased. After transfection with miR-381 inhibitor, USP39 expression was significantly increased, cell proliferation increased, and cell apoptosis decreased. Overexpression of USP39 significantly increased the invasion ability and cell survival curve ( p < 0.05 ). In conclusion, overexpression of miR-381 can regulate the expression of USP39, inhibit the proliferation and invasion of cancer cells, and induce apoptosis of cancer cells. This may provide a new perspective and strategy for targeted therapy of non-small-cell lung cancer.
