RESUMEN

Ubiquitin-specific peptidase 46 (USP46) functions as a deubiquitinating enzyme, facilitating the removal of ubiquitin molecules attached to substrate proteins and playing a critical role in cancer and neurodegenerative diseases. However, its function in innate antiviral immunity is unknown. In this study we cloned and identified bcUSP46, a homolog of USP46 from black carp. We discovered that overexpression of bcUSP46 enhanced the transcription of interferon (IFN) promoters and increased the expression of IFN, PKR, and Mx1. In addition, bcUSP46 knockdown significantly inhibited the expression of ISG genes, as well as the antiviral activity of the host cells. Interestingly, when bcUSP46 was co-expressed with the RLR factors, it significantly enhanced the activity of the IFN promoter mediated by these factors, especially TANK-binding kinase 1 (TBK1). The subsequent co-immunoprecipitation (co-IP) and immunofluorescence (IF) assay confirmed the association between bcUSP46 and bcTBK1. Noteworthily, co-expression of bcUSP46 with bcTBK1 led to an elevation of bcTBK1 protein level. Further analysis revealed that bcUSP46 stabilized bcTBK1 by eliminating the K48-linked ubiquitination of bcTBK1. Overall, our findings highlight the unique role of USP46 in modulating TBK1/IFN signaling and enrich our knowledge of the function of deubiquitination in regulating innate immunity in vertebrates.

Asunto(s)

Carpas , Proteínas de Peces , Inmunidad Innata , Interferones , Proteínas Serina-Treonina Quinasas , Transducción de Señal , Ubiquitinación , Carpas/inmunología , Animales , Proteínas de Peces/metabolismo , Proteínas de Peces/genética , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas Serina-Treonina Quinasas/genética , Interferones/metabolismo , Interferones/genética , Humanos , Proteasas Ubiquitina-Específicas/metabolismo , Proteasas Ubiquitina-Específicas/genética

RESUMEN

Α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors (AMPARs) are crucial for properties of synaptic plasticity, such as long-term potentiation (LTP). LTP impairment can occur early in the onset of Alzheimer's disease (AD). The downregulation or decreased abundance of AMPAR expression in the postsynaptic membrane is closely associated with LTP impairment. Ceftriaxone (Cef) can improve LTP impairment in the early stages of AD in a mouse model. The purpose of this study was to explore the mechanism underlying this process from the aspects of AMPAR expression and ubiquitination degree. In this study, we found that ß-amyloid (Aß) treatment induced hippocampal LTP impairment and AMPAR downregulation and ubiquitination. Cef pretreatment ameliorated Aß-induced hippocampal LTP impairment, reduced AMPAR ubiquitination, and increased AMPAR expression, especially in the plasma membrane, in Aß-treated mice. Administration of USP46 siRNA and DHK (a specific blocker of glutamate transporter-1) significantly inhibited the above effects of Cef, suggesting a role for anti-AMPAR ubiquitination and upregulation of glutamate transporter-1 (GLT-1) in the Cef-induced improvements mentioned above. The above findings demonstrate that pretreatment with Cef effectively mitigated Aß-induced impairment of hippocampal LTP by suppressing the ubiquitination process of AMPARs in a GLT-1-dependent manner. These results provide novel insights into the underlying mechanisms elucidating the anti-AD by Cef.

Asunto(s)

Péptidos beta-Amiloides , Ceftriaxona , Potenciación a Largo Plazo , Ratones Endogámicos C57BL , Receptores AMPA , Ubiquitinación , Animales , Ceftriaxona/farmacología , Potenciación a Largo Plazo/efectos de los fármacos , Receptores AMPA/metabolismo , Ubiquitinación/efectos de los fármacos , Péptidos beta-Amiloides/metabolismo , Masculino , Hipocampo/metabolismo , Hipocampo/efectos de los fármacos , Transportador 2 de Aminoácidos Excitadores/metabolismo , Ratones

RESUMEN

Tamoxifen (TAM) is the primary drug for treating estrogen receptor alpha-positive (ER+) breast cancer (BC). However, resistance to TAM can develop in some patients, limiting its therapeutic efficacy. The ubiquitin-specific protease (USP) family has been associated with the development, progression, and drug resistance of various cancers. To explore the role of USPs in TAM resistance in BC, we used qRT-PCR to compare USP expression between TAM-sensitive (MCF-7 and T47D) and TAM-resistant cells (MCF-7R and T47DR). We then modulated USP46 expression and examined its impact on cell proliferation, drug resistance (via CCK-8 and EdU experiments), glycolysis levels (using a glycolysis detection assay), protein interactions (confirmed by co-IP), and protein changes (analyzed through Western blotting). Our findings revealed that USP46 was significantly overexpressed in TAM-resistant BC cells, leading to the inhibition of the ubiquitin degradation of polypyrimidine tract-binding protein 1 (PTBP1). Overexpression of PTBP1 increased the PKM2/PKM1 ratio, promoted glycolysis, and intensified TAM resistance in BC cells. Knockdown of USP46 induced downregulation of PTBP1 protein by promoting its K48-linked ubiquitination, resulting in a decreased PKM2/PKM1 ratio, reduced glycolysis, and heightened TAM sensitivity in BC cells. In conclusion, this study highlights the critical role of the USP46/PTBP1/PKM2 axis in TAM resistance in BC. Targeted therapy against USP46 may represent a promising strategy to improve the prognosis of TAM-resistant patients.

Asunto(s)

Neoplasias de la Mama , Tamoxifeno , Humanos , Femenino , Tamoxifeno/farmacología , Tamoxifeno/uso terapéutico , Neoplasias de la Mama/tratamiento farmacológico , Neoplasias de la Mama/genética , Neoplasias de la Mama/metabolismo , Células MCF-7 , Resistencia a Antineoplásicos/genética , Glucólisis , Ribonucleoproteínas Nucleares Heterogéneas/genética , Ribonucleoproteínas Nucleares Heterogéneas/metabolismo , Proteína de Unión al Tracto de Polipirimidina/genética , Proteína de Unión al Tracto de Polipirimidina/metabolismo

RESUMEN

Triple-negative breast cancer (TNBC) is a malignancy with high metastasis rate and poor prognosis. Limited drugs are effective for the treatment of TNBC patients. Ubiquitin specific proteases (USPs) are important posttranscription modulators that promote protein stability by reducing the ubiquitination of the proteins. Aberrant expression of USPs is involved in the development of numerous cancers. However, it remains poorly understood on the role of USP46 in TNBC growth and metastasis. In this study, we explored the clinical relevance, function and molecular mechanisms of USP46 in TNBC. USP46 expression was increased in breast cancer tissues. High expression of USP46 was associated with the poorer prognosis of the patients. Overexpression and knockdown experiments demonstrated that USP46 was critical for TNBC cell growth, migration, and tumorigenesis. Mechanistically, USP46 enhanced the protein stability of phosphoglycerate mutase 1 (PGAM1) via direct interaction. Importantly, USP46 stimulated the glycolysis and promoted the malignant growth of TNBC cells through upregulation of PGAM1. Our study reveals that USP46/PGAM1 axis contributes to TNBC progression and is a potential target for the treatment of TNBC patients.

Asunto(s)

Neoplasias de la Mama Triple Negativas , Proteasas Ubiquitina-Específicas , Humanos , Línea Celular Tumoral , Movimiento Celular , Proliferación Celular , Regulación Neoplásica de la Expresión Génica , Glucólisis , Fosfoglicerato Mutasa/genética , Fosfoglicerato Mutasa/metabolismo , Neoplasias de la Mama Triple Negativas/genética , Neoplasias de la Mama Triple Negativas/metabolismo , Neoplasias de la Mama Triple Negativas/patología , Proteasas Ubiquitina-Específicas/genética , Proteasas Ubiquitina-Específicas/metabolismo

RESUMEN

Micro-RNAs are involved in the occurrence and development of hepatocellular carcinoma (HCC) as potential therapeutic targets for HCC. In this study, we found that miR-27a-3p was highly expressed in HCC, which was associated with lower survival rates of HCC patients. In vivo and in vitro functional experiments confirmed that over-expression or knock-down miR-27a-3p could significantly affect the proliferation ability of HCCLM3 and Huh-7, two HCC cell lines. Ubiquitin-specific protease 46 (USP46) was confirmed as the key target gene of miR-27a-3p in HCC via RNA-seq, quantitative polymerase chain reaction, Western blotting, and luciferase report. When knocking down USP46, the proliferation activity of HCC cells was significantly enhanced, while it was significantly inhibited after over-expressing USP4. Above results suggest that the abnormally over-expressed miR-27a-3p in liver promotes the proliferation of cancer cells and accelerates the development of HCC by targeting inhibition the expression of USP46. Targeting miR-27a-3p may be an effective strategy for prevention and treatment of HCC.

Asunto(s)

Carcinoma Hepatocelular , Neoplasias Hepáticas , MicroARNs , Carcinoma Hepatocelular/metabolismo , Línea Celular Tumoral , Proliferación Celular/genética , Endopeptidasas , Regulación Neoplásica de la Expresión Génica , Humanos , Neoplasias Hepáticas/metabolismo , MicroARNs/genética , MicroARNs/metabolismo , Proteasas Ubiquitina-Específicas/genética , Proteasas Ubiquitina-Específicas/metabolismo

RESUMEN

Introduction: Dynamic proteolysis, through the ubiquitin-proteasome system, has an important role in DNA transcription and cell cycle, and is considered to modulate cell stress response and synaptic plasticity. We investigated whether genetic variants in the ubiquitin carboxyl-terminal hydrolase 46 (USP46) would be associated with post-traumatic stress disorder (PTSD) in people with exposure to combat trauma using a case-control candidate gene association design. Methods: Korean male veterans exposed to the Vietnam War were grouped into those with (n = 128) and without (n = 128) PTSD. Seven tagging SNPs of USP46 were selected, and single-marker and haplotype-based association analyses were performed. All analyses were adjusted for sociodemographic factors and levels of combat exposure severity and alcohol problem. Results: One single-marker (rs2244291) showed nominal evidence of association with PTSD status and with the "re-experiencing" cluster, although the association was not significant after Bonferroni correction. No significant association with the other SNPs or the haplotypes was detected. Conclusion: The present finding suggests preliminarily that genetic vulnerability regarding the ubiquitin-proteasome system may be related to fear memory processes and the development of PTSD symptoms after trauma exposure. Further studies with a larger sample size will be needed to examine the role of the ubiquitin-proteasome system including USP46 in PTSD.

RESUMEN

Endometrial cancer (EC) ranks as the fourth most common diagnosed cancer type in females worldwide. MicroRNAs (miRNAs) are important regulators with crucial roles in regulating diverse biologic processes, including tumor initiation and progression. Previous studies have demonstrated that miR-27a was correlated with the tumorigenesis of various cancers. However, its expression and biologic role in EC remain to be determined. This study aimed to clarify whether miR-27a acts as an oncogene in endometrial cancer (EC) by downregulating ubiquitin specific peptidase 46 (USP46). Expression of miR-27a was measured by qRT-PCR, and the results demonstrated that miR-27a was upregulated in EC cell lines compared to normal cell lines. Cell counting kit-8 (CCK-8) and wound-healing assays demonstrated that overexpression of miR-27a significantly promoted cell proliferation and migration. Online prediction algorithm and dual luciferase activity reporter assay revealed that USP46 acts as a direct target of miR-27a. USP46 expression was downregulated in EC cell lines during miR-27a overexpression. Collectively, our results indicated that miR-27a targets USP46 to promote EC cell proliferation and migration, suggesting an oncogene role of miR-27a in EC.

RESUMEN

The deubiquitinating enzyme USP46 (ubiquitin-specific protease 46) is implicated in various cancers. However, its role and regulatory mechanism in HCC (hepatocellular carcinoma) are still unknown. In this study, we showed that USP46 is downregulated in HCC tissues and that low USP46 levels are associated with poor prognosis in HCC patients. In functional experiments, overexpression of USP46 impaired proliferation and metastasis of HCC cells, whereas knockdown of USP46 enhanced cell proliferation and invasiveness in vitro and in vivo. Furthermore, we found that USP46 suppresses HCC cell proliferation and metastasis by inhibiting YAP1. Ectopic expression of YAP1 rescued the inhibition of cell proliferation and metastasis caused by USP46 overexpression. Mechanistically, USP46 promotes the degradation of YAP1 by increasing expression of MST1, and the increase in MST1 protein antagonizes YAP1 to suppress HCC progression. Finally, we demonstrated that USP46 stabilizes the MST1 protein by directly binding to it and decreasing its ubiquitination. Taken together, our results demonstrated that USP46 may be a novel tumor suppressor in HCC. Moreover, USP46 acts as a deubiquitinating enzyme of MST1 to potentiate MST1 kinase activity to suppress tumor growth and metastasis, indicating that USP46 activation may represent a potential treatment strategy for HCC.

Asunto(s)

Biomarcadores de Tumor/metabolismo , Carcinoma Hepatocelular/patología , Endopeptidasas/metabolismo , Regulación Neoplásica de la Expresión Génica , Factor de Crecimiento de Hepatocito/metabolismo , Neoplasias Hepáticas/patología , Proteínas Proto-Oncogénicas/metabolismo , Ubiquitinación , Animales , Apoptosis , Biomarcadores de Tumor/genética , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/metabolismo , Movimiento Celular , Proliferación Celular , Endopeptidasas/genética , Femenino , Factor de Crecimiento de Hepatocito/genética , Humanos , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Masculino , Ratones , Ratones Desnudos , Persona de Mediana Edad , Invasividad Neoplásica , Fosforilación , Pronóstico , Proteínas Proto-Oncogénicas/genética , Células Tumorales Cultivadas , Ensayos Antitumor por Modelo de Xenoinjerto

RESUMEN

Reversible modification of AMPA receptors (AMPARs) with ubiquitin regulates receptor levels at synapses and controls synaptic strength. The conserved deubiquitinating enzyme (DUB) ubiquitin-specific protease-46 (USP-46) removes ubiquitin from AMPARs and protects them from degradation in both Caenorhabditis elegans and mammals. Although DUBs are critical for diverse physiological processes, the mechanisms that regulate DUBs, especially in the nervous system, are not well understood. We and others previously showed that the WD40-repeat proteins WDR-48 and WDR-20 bind to and stimulate the catalytic activity of USP-46. Here, we identify an activity-dependent mechanism that regulates WDR-20 expression and show that WDR-20 works together with USP-46 and WDR-48 to promote surface levels of the C. elegans AMPAR GLR-1. usp-46, wdr-48, and wdr-20 loss-of-function mutants exhibit reduced levels of GLR-1 at the neuronal surface and corresponding defects in GLR-1-mediated behavior. Increased expression of WDR-20, but not WDR-48, is sufficient to increase GLR-1 surface levels in an usp-46-dependent manner. Loss of usp-46, wdr-48, and wdr-20 function reduces the rate of local GLR-1 insertion in neurites, whereas overexpression of wdr-20 is sufficient to increase the rate of GLR-1 insertion. Genetic manipulations that chronically reduce or increase glutamate signaling result in reciprocal alterations in wdr-20 transcription and homeostatic compensatory changes in surface GLR-1 levels that are dependent on wdr-20 This study identifies wdr-20 as a novel activity-regulated gene that couples chronic changes in synaptic activity with increased local insertion and surface levels of GLR-1 via the DUB USP-46.SIGNIFICANCE STATEMENT Deubiquitinating enzymes (DUBs) are critical regulators of synapse development and function; however, the regulatory mechanisms that control their various physiological functions are not well understood. This study identifies a novel role for the DUB ubiquitin-specific protease-46 (USP-46) and its associated regulatory protein WD40-repeat protein-20 (WDR-20) in regulating local insertion of glutamate receptors into the neuronal cell surface. This work also identifies WDR-20 as an activity-regulated gene that couples chronic changes in synaptic activity with homeostatic compensatory increases in surface levels of GLR-1 via USP-46. Given that 35% of USP family DUBs associate with WDR proteins, understanding the mechanisms by which WDR proteins regulate USP-46 could have implications for a large number of DUBs in other cell types.

Asunto(s)

Proteínas de Caenorhabditis elegans/metabolismo , Proteínas Portadoras/metabolismo , Membrana Celular/metabolismo , Enzimas Desubicuitinizantes/metabolismo , Endopeptidasas/metabolismo , Receptores de Glutamato/metabolismo , Animales , Animales Modificados Genéticamente , Caenorhabditis elegans , Proteínas de Caenorhabditis elegans/genética , Proteínas Portadoras/genética , Membrana Celular/genética , Enzimas Desubicuitinizantes/genética , Endopeptidasas/genética , Receptores de Glutamato/genética

RESUMEN

E6 from high-risk strains of HPV is well known to transform cells by deregulating p53. We reported that in HPV transformed cell-lines E6 from high-risk HPV can recruit the USP46 deubiquitinase to substrates such as Cdt2 and stabilize the latter, and that USP46 is important for growth of HPV induced tumors in xenografts. Here we show that in cervical cancer biopsies the stabilization of Cdt2 in the HPV-induced cancers leads to the decrease of a CRL4-Cdt2 substrate, the histone H4K20 mono-methyltransferase Set8, and decrease in H4K20me1 or H4K20me3 that can be detected by immunohistochemistry. In HPV-transformed cancer cell lines in vitro, knockdown of E6 decreases Cdt2 and increases Set8. Co-knockdown of Set8 shows that some of the gene expression changes produced by E6 knockdown is due to the increase of Set8. EGFR and EGFR regulated genes were identified in this set of genes. Turning to the mechanism by which E6 stabilizes Cdt2, we find that a purified E6:USP46 complex has significantly more de-ubiquitinase activity in vitro than USP46 alone, demonstrating that E6 can directly interact with USP46 in the absence of other proteins and that it can substitute for the known activators of USP46, UAF1 and WDR20. Deletion mapping of Cdt2 shows that there are three discrete, but redundant, parts of the substrate that are essential for stabilization by E6: USP46. The helix-loop-helix region or the WD40 repeat driven beta-propeller structure of Cdt2 are dispensable for the stabilization implying that interaction with DDB1 (and the rest of the CRL4 complex) or with the substrate of the CRL4-Cdt2 E3 ligase is not necessary for E6:USP46 to interact with and stabilize Cdt2. The identification of 50 amino acid stretches in the 731 amino acid Cdt2 protein as being important for the stabilization by E6 underlines the specificity of the process. In summary, E6 activates the deubiquitinase activity of USP46, stabilizes Cdt2 utilizing multiple sites on Cdt2, and leads to degradation of Set8 and changes in gene-expression in HPV-transformed cells.

RESUMEN

Esophageal squamous cell carcinoma (ESCC) has high aggressiveness and poor prognosis, and is the major histological subtype of esophageal cancer in East Asia and East Africa. In this study, we found that USP46, a deubiquitinating enzyme, is overexpressed in clinical ESCC samples, especially in patients with positive lymph node metastasis. Moreover, USP46 enhances the migration and invasion of ESCC cells by mediating the EMT process in vitro, and promotes lymph nodes and lung metastasis of ESCC in vivo. In addition, we found that USP46 is a bona fide deubiquitinating enzyme to stabilize the protein level of ENO1 through deubiquitination. ENO1 protein level was also positively correlated with USP46 in the ESCC samples. In summary, these findings reveal the functional role of USP46 as a deubiquitinating enzyme on ESCC metastasis, providing us a potential therapeutic target for the treatment of ESCC.

Asunto(s)

Biomarcadores de Tumor/metabolismo , Carcinoma de Células Escamosas/patología , Proteínas de Unión al ADN/metabolismo , Neoplasias Esofágicas/metabolismo , Carcinoma de Células Escamosas de Esófago/metabolismo , Metástasis de la Neoplasia/patología , Fosfopiruvato Hidratasa/metabolismo , Proteínas Supresoras de Tumor/metabolismo , Carcinoma de Células Escamosas/metabolismo , Movimiento Celular/fisiología , Proliferación Celular/genética , Neoplasias Esofágicas/patología , Regulación Neoplásica de la Expresión Génica/genética , Neoplasias de Cabeza y Cuello/genética , Neoplasias de Cabeza y Cuello/metabolismo , Neoplasias de Cabeza y Cuello/patología , Humanos , Invasividad Neoplásica/patología , Proteasas Ubiquitina-Específicas/genética

RESUMEN

Ubiquitination is a reversible post-translational modification that has emerged as a critical regulator of synapse development and function. However, the mechanisms that regulate the deubiquitinating enzymes (DUBs) responsible for the removal of ubiquitin from target proteins are poorly understood. We have previously shown that the DUB ubiquitin-specific protease 46 (USP-46) removes ubiquitin from the glutamate receptor GLR-1 and regulates its trafficking and degradation in Caenorhabditis elegans We found that the WD40-repeat proteins WDR-20 and WDR-48 bind and stimulate the catalytic activity of USP-46. Here, we identified another mechanism by which WDR-48 regulates USP-46. We found that increased expression of WDR-48, but not WDR-20, promotes USP-46 abundance in mammalian cells in culture and in C. elegans neurons in vivo Inhibition of the proteasome increased USP-46 abundance, and this effect was nonadditive with increased WDR-48 expression. We found that USP-46 is ubiquitinated and that expression of WDR-48 reduces the levels of ubiquitin-USP-46 conjugates and increases the t1/2 of USP-46. A point-mutated WDR-48 variant that disrupts binding to USP-46 was unable to promote USP-46 abundance in vivo Finally, siRNA-mediated knockdown of wdr48 destabilizes USP46 in mammalian cells. Together, these results support a model in which WDR-48 binds and stabilizes USP-46 protein levels by preventing the ubiquitination and degradation of USP-46 in the proteasome. Given that a large number of USPs interact with WDR proteins, we propose that stabilization of DUBs by their interacting WDR proteins may be a conserved and widely used mechanism that controls DUB availability and function.

Asunto(s)

Caenorhabditis elegans/metabolismo , Animales , Caenorhabditis elegans/química , Estabilidad de Enzimas , Células HEK293 , Humanos , Proteolisis , Ubiquitinación , Repeticiones WD40

RESUMEN

USP46, a member of the ubiquitin-specific protease family, plays essential roles in cancer cell proliferation and metastasis and is used as a candidate target for cancer therapeutics. However, the effects of USP46 on renal cell carcinoma (RCC) and its underlying molecular mechanism remain unknown. In this study, the predictive and prognostic relevance of USP46 in RCC, patient-derived primary tissues, and normal liver tissues obtained from the TCGA dataset were analyzed for the USP46 mRNA levels or prognostic relevance. Gain-of-function or loss-of-function assays were used to evaluate the vital roles of USP46 in tumor cell proliferation and cell migration. As a result, the USP46 expression level in RCC is highly decreased compared to normal tissues, and the Kaplan-Meier curve showed that USP46 high expression patients had good prognoses. Functionally, the forced expression of USP46 significantly restrained tumor cell proliferation, colony formation, and cell migration. The shRNA mediated USP46 knockdown cells exhibited the opposite results. We further showed that ectopically expressed USP46 obviously inhibited the AKT signaling pathway in cancer cells, while USP46 depletion caused a dramatic increase in AKT activity reflected by phosphorylation in the serine and threonine residues of AKT or downstream p70S6K1. Importantly, MK2206, a specific AKT inhibitor, completely counteracted the effects on cell proliferation, cell migration, and AKT activity in the USP46 depletion cells. We thus revealed a novel mechanism of USP46 regulation in RCC, and our data indicate that USP46 is a tumor suppressor in RCC via AKT signaling pathway inactivation.

Asunto(s)

Carcinogénesis/genética , Carcinoma de Células Renales/genética , Endopeptidasas/genética , Neoplasias Renales/genética , Proteínas Proto-Oncogénicas c-akt/genética , Carcinogénesis/metabolismo , Carcinoma de Células Renales/metabolismo , Carcinoma de Células Renales/patología , Línea Celular Tumoral , Movimiento Celular/genética , Proliferación Celular/genética , Endopeptidasas/metabolismo , Células HEK293 , Humanos , Estimación de Kaplan-Meier , Neoplasias Renales/metabolismo , Neoplasias Renales/patología , Pronóstico , Proteínas Proto-Oncogénicas c-akt/metabolismo , Interferencia de ARN , Transducción de Señal/genética

RESUMEN

OBJECTIVE: Ubiquitin-specific peptidase 46 gene (USP46) polymorphisms is part of ubiquitin-proteasome system, which is responsible for dynamic cellular processes such as the regulation of cell cycle. USP46 has been reported to be associated with major depressive disorder. The objective of the present study was to investigate the association of USP46 polymorphisms with affective temperamental traits in healthy subjects. METHODS: A total of 557 Korean healthy volunteers were recruited, and 545 subjects (328 male, 217 female) were included in the final analysis. The DNA of the subjects was isolated from saliva samples. Two single-nucleotide polymorphisms (SNPs) rs346005, rs2244291 in USP46 were genotyped. Affective temperaments were assessed using the Korean version of Temperament Evaluation of the Memphis, Pisa, Paris, and San Diego Autoquestionnaire (TEMPS-A). RESULTS: A significant association was found between rs346005 genotypes and TEMPS-A only in male subjects. In particular, subjects with the CC genotype of rs346005 showed a more depressive temperament than subjects with AA or CA genotypes in males. For rs2244291, there were no associations between the rs2244291 genotypes and TEMPS-A scores. CONCLUSION: Some affective temperaments may serve as a genetic predisposing factors for affective disorders, such as depressive disorder, via vulnerability genes related to the ubiquitin-proteasome system.

RESUMEN

The human deubiquitinases USP12 and USP46 are very closely related paralogs with critical functions as tumor suppressors. The catalytic activity of these enzymes is regulated by two cofactors: UAF1 and WDR20. USP12 and USP46 show nearly 90% amino acid sequence identity and share some cellular activities, but have also evolved non-overlapping functions. We hypothesized that, correlating with their functional divergence, the subcellular localization of USP12 and USP46 might be differentially regulated by their cofactors. We used confocal and live microscopy analyses of epitope-tagged proteins to determine the effect of UAF1 and WDR20 on the localization of USP12 and USP46. We found that WDR20 differently modulated the localization of the DUBs, promoting recruitment of USP12, but not USP46, to the plasma membrane. Using site-directed mutagenesis, we generated a large set of USP12 and WDR20 mutants to characterize in detail the mechanisms and sequence determinants that modulate the subcellular localization of the USP12/UAF1/WDR20 complex. Our data suggest that the USP12/UAF1/WDR20 complex dynamically shuttles between the plasma membrane, cytoplasm and nucleus. This shuttling involved active nuclear export mediated by the CRM1 pathway, and required a short N-terminal motif (1MEIL4) in USP12, as well as a novel nuclear export sequence (450MDGAIASGVSKFATLSLHD468) in WDR20. In conclusion, USP12 and USP46 have evolved divergently in terms of cofactor binding-regulated subcellular localization. WDR20 plays a crucial role in as a "targeting subunit" that modulates CRM1-dependent shuttling of the USP12/UAF1/WDR20 complex between the plasma membrane, cytoplasm and nucleus.

Asunto(s)

Proteínas Portadoras/metabolismo , Membrana Celular/metabolismo , Núcleo Celular/metabolismo , Ubiquitina Tiolesterasa/metabolismo , Transporte Activo de Núcleo Celular , Secuencias de Aminoácidos , Secuencia de Aminoácidos , Células HEK293 , Células HeLa , Humanos , Carioferinas/metabolismo , Modelos Biológicos , Señales de Exportación Nuclear , Unión Proteica , Transporte de Proteínas , Receptores Citoplasmáticos y Nucleares/metabolismo , Relación Estructura-Actividad , Ubiquitina Tiolesterasa/química , Proteína Exportina 1

RESUMEN

OBJECTIVE: Ubiquitin-specific peptidase 46 gene (USP46) polymorphisms is part of ubiquitin-proteasome system, which is responsible for dynamic cellular processes such as the regulation of cell cycle. USP46 has been reported to be associated with major depressive disorder. The objective of the present study was to investigate the association of USP46 polymorphisms with affective temperamental traits in healthy subjects. METHODS: A total of 557 Korean healthy volunteers were recruited, and 545 subjects (328 male, 217 female) were included in the final analysis. The DNA of the subjects was isolated from saliva samples. Two single-nucleotide polymorphisms (SNPs) rs346005, rs2244291 in USP46 were genotyped. Affective temperaments were assessed using the Korean version of Temperament Evaluation of the Memphis, Pisa, Paris, and San Diego Autoquestionnaire (TEMPS-A). RESULTS: A significant association was found between rs346005 genotypes and TEMPS-A only in male subjects. In particular, subjects with the CC genotype of rs346005 showed a more depressive temperament than subjects with AA or CA genotypes in males. For rs2244291, there were no associations between the rs2244291 genotypes and TEMPS-A scores. CONCLUSION: Some affective temperaments may serve as a genetic predisposing factors for affective disorders, such as depressive disorder, via vulnerability genes related to the ubiquitin-proteasome system.

Asunto(s)

Humanos , Masculino , Causalidad , Ciclo Celular , Trastorno Depresivo , Trastorno Depresivo Mayor , ADN , Estudios de Asociación Genética , Genotipo , Voluntarios Sanos , Trastornos del Humor , Saliva , Temperamento , Voluntarios

RESUMEN

High-risk human papilloma viruses (HPVs) cause cervical, anal, and oropharyngeal cancers, unlike the low-risk HPVs, which cause benign lesions. E6 oncoproteins from the high-risk strains are essential for cell proliferation and transformation in HPV-induced cancers. We report that a cellular deubiquitinase, USP46, is selectively recruited by the E6 of high-risk, but not low-risk, HPV to deubiqutinate and stabilize Cdt2/DTL. Stabilization of Cdt2, a component of the CRL4Cdt2 E3 ubiquitin ligase, limits the level of Set8, an epigenetic writer, and promotes cell proliferation. USP46 is essential for the proliferation of HPV-transformed cells, but not of cells without HPV. Cdt2 is elevated in human cervical cancers and knockdown of USP46 inhibits HPV-transformed tumor growth in xenografts. Recruitment of a cellular deubiquitinase to stabilize key cellular proteins is an important activity of oncogenic E6, and the importance of E6-USP46-Cdt2-Set8 pathway in HPV-induced cancers makes USP46 a target for the therapy of such cancers.

Asunto(s)

Endopeptidasas/genética , Papillomavirus Humano 16/genética , Papillomavirus Humano 18/genética , Proteínas Nucleares/genética , Infecciones por Papillomavirus/genética , Neoplasias del Cuello Uterino/genética , Animales , Ciclo Celular , Línea Celular Tumoral , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Endopeptidasas/metabolismo , Femenino , Regulación de la Expresión Génica , Células HeLa , N-Metiltransferasa de Histona-Lisina/genética , N-Metiltransferasa de Histona-Lisina/metabolismo , Interacciones Huésped-Patógeno/genética , Papillomavirus Humano 16/metabolismo , Papillomavirus Humano 16/patogenicidad , Papillomavirus Humano 18/metabolismo , Papillomavirus Humano 18/patogenicidad , Humanos , Inyecciones Intralesiones , Ratones , Proteínas Nucleares/metabolismo , Proteínas Oncogénicas Virales/genética , Proteínas Oncogénicas Virales/metabolismo , Infecciones por Papillomavirus/enzimología , Infecciones por Papillomavirus/patología , Infecciones por Papillomavirus/virología , ARN Interferente Pequeño/genética , ARN Interferente Pequeño/metabolismo , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Proteínas Represoras/genética , Proteínas Represoras/metabolismo , Transducción de Señal , Ubiquitina-Proteína Ligasas/genética , Ubiquitina-Proteína Ligasas/metabolismo , Neoplasias del Cuello Uterino/enzimología , Neoplasias del Cuello Uterino/patología , Neoplasias del Cuello Uterino/virología , Ensayos Antitumor por Modelo de Xenoinjerto

RESUMEN

Metastatic castration resistant prostate cancer is one of the main causes of male cancer associated deaths worldwide. Development of resistance is inevitable in patients treated with anti-androgen therapies. This highlights a need for novel therapeutic strategies that would be aimed upstream of the androgen receptor (AR). Here we report that the novel small molecule anti-androgen, galeterone targets USP12 and USP46, two highly homologous deubiquitinating enzymes that control the AR-AKT-MDM2-P53 signalling pathway. Consequently, galeterone is effective in multiple models of prostate cancer including both castrate resistant and AR-negative prostate cancer. However, we have observed that USP12 and USP46 selectively regulate full length AR protein but not the AR variants. This is the first report of deubiquitinating enzyme targeting as a strategy in prostate cancer treatment which we show to be effective in multiple, currently incurable models of this disease.

RESUMEN

As the primary mediator for synaptic transmission, AMPA receptors (AMPARs) are crucial for synaptic plasticity and higher brain functions. A downregulation of AMPAR expression has been indicated as one of the early pathological molecular alterations in Alzheimer's disease (AD), presumably via amyloid-ß (Aß). However, the molecular mechanisms leading to the loss of AMPARs remain less clear. We report that in primary neurons, application of Aß triggers AMPAR internalization accompanied with a decrease in cell-surface AMPAR expression. Importantly, in both Aß-treated neurons and human brain tissue from AD patients, we observed a significant decrease in total AMPAR amount and an enhancement in AMPAR ubiquitination. Consistent with facilitated receptor degradation, AMPARs show higher turnover rates in the presence of Aß. Furthermore, AD brain lysates and Aß-incubated neurons show increased expression of the AMPAR E3 ligase Nedd4 and decreased expression of AMPAR deubiquitinase USP46. Changes in these enzymes are responsible for the Aß-dependent AMPAR reduction. These findings indicate that AMPAR ubiquitination acts as the key molecular event leading to the loss of AMPARs and thus suppressed synaptic transmission in AD.

Asunto(s)

Enfermedad de Alzheimer/metabolismo , Péptidos beta-Amiloides/metabolismo , Encéfalo/metabolismo , Neuronas/metabolismo , Receptores AMPA/metabolismo , Animales , Endopeptidasas/metabolismo , Células HEK293 , Humanos , Ubiquitina-Proteína Ligasas Nedd4/metabolismo , Cultivo Primario de Células , Proteolisis , Ratas , Ubiquitinación/fisiología

RESUMEN

Posttranslational modification of proteins by ubiquitin regulates synapse development and synaptic transmission. Much progress has been made investigating the role of ubiquitin ligases at the synapse, however very little is known about the deubiquitinating enzymes (DUBs) which remove ubiquitin from target proteins. Although there are far fewer DUBs than ubiquitin ligases encoded by the human genome, it is becoming clear that DUBs have very specific physiological functions, suggesting that DUB activity is tightly regulated in vivo. Many DUBs function as part of larger protein complexes, and multiple regulatory mechanisms exist to control the expression, localization and catalytic activity of DUBs. In this review article, we focus on the role of the DUB USP46 in the nervous system, and illustrate potential mechanisms of regulating DUBs by describing how USP46 is regulated by two WD40-repeat (WDR) proteins, WDR48/UAF1 and WDR20, based on recent structural studies and genetic analyses in vivo.