RESUMEN
The Hippo-YAP signaling pathway plays a central role in many biological processes such as regulating cell fate, organ size, and tissue growth, and its key components are spatiotemporally expressed and posttranslationally modified during these processes. Neddylation is a posttranslational modification that involves the covalent attachment of NEDD8 to target proteins by NEDD8-specific E1-E2-E3 enzymes. Whether neddylation is involved in Hippo-YAP signaling remains poorly understood. Here, we provide evidence supporting the critical role of NEDD8 in facilitating the Hippo-YAP signaling pathway by mediating neddylation of the transcriptional coactivator yes-associated protein 1 (YAP1). Overexpression of NEDD8 induces YAP1 neddylation and enhances YAP1 transactivity, but inhibition of neddylation suppresses YAP1 transactivity and attenuates YAP1 nuclear accumulation. Furthermore, inhibition of YAP1 signaling promotes MLN4924-induced ovarian granulosa cells apoptosis and disruption of nedd8 in zebrafish results in downregulation of yap1-activated genes and upregulation of yap1-repressed genes. Further assays show that the xiap ligase promotes nedd8 conjugates to yap1 and that yap1 neddylation. In addition, we identify lysine 159 as a major neddylation site on YAP1. These findings reveal a novel mechanism for neddylation in the regulation of Hippo-YAP signaling.
RESUMEN
IFN regulatory factor 3 (IRF3) is the transcription factor crucial for the production of type I IFN in viral defence and inflammatory responses. The activity of IRF3 is strictly modulated by post-translational modifications (PTMs) to effectively protect the host from infection while avoiding excessive immunopathology. Here, we report that zebrafish myosin-regulated light chain interacting protein b (mylipb) inhibits virus-induced type I IFN production via two synergistic mechanisms: induction of autophagic degradation of irf3 and reduction of irf3 phosphorylation. In vivo, mylipb-null zebrafish exhibit reduced lethality and viral mRNA levels compared to controls. At the cellular level, overexpression of mylipb significantly reduces cellular antiviral capacity, and promotes viral proliferation. Mechanistically, mylipb associates with irf3 and targets Lys 352 to increase K6-linked polyubiquitination, dependent on its E3 ubiquitin ligase activity, leading to autophagic degradation of irf3. Meanwhile, mylipb acts as a decoy substrate for the phosphokinase tbk1 to attenuate irf3 phosphorylation and cellular antiviral responses independent of its enzymatic activity. These findings support a critical role for zebrafish mylipb in the limitation of antiviral innate immunity through two synergistic mechanisms targeting irf3.
Asunto(s)
Inmunidad Innata , Factor 3 Regulador del Interferón , Proteínas de Pez Cebra , Pez Cebra , Animales , Factor 3 Regulador del Interferón/metabolismo , Proteínas de Pez Cebra/metabolismo , Proteínas de Pez Cebra/genética , Infecciones por Rhabdoviridae/inmunología , Fosforilación , Ubiquitinación , Humanos , Autofagia/inmunologíaRESUMEN
To effectively protect the host from viral infection while avoiding excessive immunopathology, the innate immune response must be tightly controlled. However, the precise regulation of antiviral innate immunity and the underlying mechanisms remain unclear. Here, we find that sirtuin3 (SIRT3) interacts with mitochondrial antiviral signaling protein (MAVS) to catalyze MAVS deacetylation at lysine residue 7 (K7), which promotes MAVS aggregation, as well as TANK-binding kinase I and IRF3 phosphorylation, resulting in increased MAVS activation and enhanced type I interferon signaling. Consistent with these findings, loss of Sirt3 in mice and zebrafish renders them more susceptible to viral infection compared to their wild-type (WT) siblings. However, Sirt3 and Sirt5 double-deficient mice exhibit the same viral susceptibility as their WT littermates, suggesting that loss of Sirt5 in Sirt3-deficient mice may counteract the increased viral susceptibility displayed in Sirt3-deficient mice. Thus, we not only demonstrate that SIRT3 positively regulates antiviral immunity in vitro and in vivo, likely via MAVS, but also uncover a previously unrecognized mechanism by which SIRT3 acts as an accelerator and SIRT5 as a brake to orchestrate antiviral innate immunity.
Asunto(s)
Sirtuina 3 , Sirtuinas , Virosis , Animales , Ratones , Proteínas Adaptadoras Transductoras de Señales/genética , Inmunidad Innata , Lisina , Sirtuina 3/genética , Sirtuinas/genética , Pez Cebra , Proteínas de Pez CebraRESUMEN
Oxygen is essential for aerobic organisms, but little is known about its role in antiviral immunity. Here, we report that during responses to viral infection, hypoxic conditions repress antiviral-responsive genes independently of HIF signaling. EGLN1 is identified as a key mediator of the oxygen enhancement of antiviral innate immune responses. Under sufficient oxygen conditions, EGLN1 retains its prolyl hydroxylase activity to catalyze the hydroxylation of IRF3 at proline 10. This modification enhances IRF3 phosphorylation, dimerization and nuclear translocation, leading to subsequent IRF3 activation. Furthermore, mice and zebrafish with Egln1 deletion, treatment with the EGLN inhibitor FG4592, or mice carrying an Irf3 P10A mutation are more susceptible to viral infections. These findings not only reveal a direct link between oxygen and antiviral responses, but also provide insight into the mechanisms by which oxygen regulates innate immunity.
Asunto(s)
Prolina Dioxigenasas del Factor Inducible por Hipoxia , Inmunidad Innata , Factor 3 Regulador del Interferón , Oxígeno , Prolina , Pez Cebra , Animales , Prolina Dioxigenasas del Factor Inducible por Hipoxia/metabolismo , Prolina Dioxigenasas del Factor Inducible por Hipoxia/genética , Factor 3 Regulador del Interferón/metabolismo , Hidroxilación , Humanos , Prolina/metabolismo , Ratones , Oxígeno/metabolismo , Células HEK293 , Fosforilación , Ratones Noqueados , Transducción de Señal , Ratones Endogámicos C57BLRESUMEN
Testosterone is closely associated with lipid metabolism and known to affect body fat composition and muscle mass in males. However, the mechanisms by which testosterone acts on lipid metabolism are not yet fully understood, especially in teleosts. In this study, cyp17a1-/- zebrafish ( Danio rerio) exhibited excessive visceral adipose tissue (VAT), lipid content, and up-regulated expression and activity of hepatic de novo lipogenesis (DNL) enzymes. The assay for transposase accessible chromatin with sequencing (ATAC-seq) results demonstrated that chromatin accessibility of DNL genes was increased in cyp17a1-/- fish compared to cyp17a1+/+ male fish, including stearoyl-CoA desaturase ( scd) and fatty acid synthase ( fasn). Androgen response element (ARE) motifs in the androgen signaling pathway were significantly enriched in cyp17a1+/+ male fish but not in cyp17a1-/- fish. Both androgen receptor ( ar)-/- and wild-type (WT) zebrafish administered with Ar antagonist flutamide displayed excessive visceral adipose tissue, lipid content, and up-regulated expression and activity of hepatic de novo lipogenesis enzymes. The Ar agonist BMS-564929 reduced the content of VAT and lipid content, and down-regulated acetyl-CoA carboxylase a ( acaca), fasn, and scd expression. Mechanistically, the rescue effect of testosterone on cyp17a1-/- fish in terms of phenotypes was abolished when ar was additionally depleted. Collectively, these findings reveal that testosterone inhibits lipid deposition by down-regulating DNL genes via Ar in zebrafish, thus expanding our understanding of the relationship between testosterone and lipid metabolism in teleosts.
Asunto(s)
Andrógenos , Lipogénesis , Masculino , Animales , Andrógenos/farmacología , Lipogénesis/genética , Pez Cebra/genética , Testosterona , Lípidos , Transducción de Señal , CromatinaRESUMEN
The regulatory mechanism of gonadal sex differentiation, which is complex and regulated by multiple factors, remains poorly understood in teleosts. Recently, we have shown that compromised androgen and estrogen synthesis with increased progestin leads to all-male differentiation with proper testis development and spermatogenesis in cytochrome P450 17a1 (cyp17a1)-/- zebrafish. In the present study, the phenotypes of female-biased sex ratio were positively correlated with higher Fanconi anemia complementation group L (fancl) expression in the gonads of doublesex and mab-3 related transcription factor 1 (dmrt1)-/- and cyp17a1-/-;dmrt1-/- fish. The additional depletion of fancl in cyp17a1-/-;dmrt1-/- zebrafish reversed the gonadal sex differentiation from all-ovary to all-testis (in cyp17a1-/-;dmrt1-/-;fancl-/- fish). Luciferase assay revealed a synergistic inhibitory effect of Dmrt1 and androgen signaling on fancl transcription. Furthermore, an interaction between Fancl and the apoptotic factor Tumour protein p53 (Tp53) was found in vitro. The interaction between Fancl and Tp53 was observed via the WD repeat domain (WDR) and C-terminal domain (CTD) of Fancl and the DNA binding domain (DBD) of Tp53, leading to the K48-linked polyubiquitination degradation of Tp53 activated by the ubiquitin ligase, Fancl. Our results show that testis fate in cyp17a1-/- fish is determined by Dmrt1, which is thought to stabilize Tp53 by inhibiting fancl transcription during the critical stage of sexual fate determination in zebrafish.
Asunto(s)
Testículo , Pez Cebra , Animales , Masculino , Femenino , Testículo/metabolismo , Pez Cebra/genética , Andrógenos/genética , Andrógenos/metabolismo , Gónadas/metabolismo , Diferenciación Sexual/genética , Estrógenos/genéticaRESUMEN
HIF1α is one of the master regulators of the hypoxia signaling pathway and its activation is regulated by multiple post-translational modifications (PTMs). Deubiquitination mediated by deubiquitylating enzymes (DUBs) is an essential PTM that mainly modulates the stability of target proteins. USP38 belongs to the ubiquitin-specific proteases (USPs). However, whether USP38 can affect hypoxia signaling is still unknown. In this study, we used quantitative real-time PCR assays to identify USPs that can influence hypoxia-responsive gene expression. We found that overexpression of USP38 increased hypoxia-responsive gene expression, but knockout of USP38 suppressed hypoxia-responsive gene expression under hypoxia. Mechanistically, USP38 interacts with HIF1α to deubiquitinate K11-linked polyubiquitination of HIF1α at Lys769, resulting in stabilization and subsequent activation of HIF1α. In addition, we show that USP38 attenuates cellular ROS and suppresses cell apoptosis under hypoxia. Thus, we reveal a novel role for USP38 in the regulation of hypoxia signaling.
Asunto(s)
Hipoxia , Transducción de Señal , Humanos , Hipoxia de la Célula/genética , Subunidad alfa del Factor 1 Inducible por Hipoxia/genética , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Proteasas Ubiquitina-Específicas/metabolismo , Ubiquitinación , Línea CelularRESUMEN
Activation of type I interferon (IFN-1) signaling is essential to protect host cells from viral infection. The full spectrum of IFN-I induction requires the activation of a number of cellular factors, including IκB kinase epsilon (IKKϵ). However, the regulation of IKKϵ activation in response to viral infection remains largely unknown. Here, we show that factor inhibiting hypoxia-inducible factor (HIF) (FIH), an asparaginyl hydroxylase, interacts with IKKϵ and catalyzes asparagine hydroxylation of IKKϵ at Asn-254, Asn-700, and Asn-701, resulting in the suppression of IKKϵ activation. FIH-mediated hydroxylation of IKKϵ prevents IKKϵ binding to TBK1 and TRAF3 and attenuates the cIAP1/cIAP2/TRAF2 E3 ubiquitin ligase complex-catalyzed K63-linked polyubiquitination of IKKϵ at Lys-416. In addition, Fih-deficient mice and zebrafish are more resistant to viral infection. This work uncovers a previously unrecognized role of FIH in suppressing IKKϵ activation for IFN signaling and antiviral immune responses.
Asunto(s)
Quinasa I-kappa B , Virosis , Animales , Ratones , Quinasa I-kappa B/metabolismo , Proteínas Represoras/metabolismo , Secuencia de Aminoácidos , Hidroxilación , Pez Cebra/metabolismo , Inmunidad InnataRESUMEN
Prolyl hydroxylase domain (PHD)-containing enzyme 3 (PHD3) belongs to the Caenorhabditis elegans gene egl-9 family of prolyl hydroxylases. PHD3 catalyzes proline hydroxylation of hypoxia-inducible factor α (HIF-α) and promotes HIF-α proteasomal degradation through coordination with the pVHL complex under normoxic conditions. However, the relationship between PHD3 and the hypoxic response is not well understood. In this study, we used quantitative real-time PCR assay and O-dianisidine staining to characterize the hypoxic response in zebrafish deficient in phd3. We found that the hypoxia-responsive genes are upregulated and the number of erythrocytes was increased in phd3-null zebrafish compared with their wild-type siblings. On the other hand, we show overexpression of phd3 suppresses HIF-transcriptional activation. In addition, we demonstrate phd3 promotes polyubiquitination of zebrafish hif-1/2α proteins, leading to their proteasomal degradation. Finally, we found that compared with wild-type zebrafish, phd3-null zebrafish are more resistant to hypoxia treatment. Therefore, we conclude phd3 has a role in hypoxia tolerance. These results highlight the importance of modulation of the hypoxia signaling pathway by phd3 in hypoxia adaptation.
Asunto(s)
Prolina Dioxigenasas del Factor Inducible por Hipoxia , Oxígeno , Procolágeno-Prolina Dioxigenasa , Proteínas de Pez Cebra , Pez Cebra , Animales , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Prolina Dioxigenasas del Factor Inducible por Hipoxia/genética , Prolina Dioxigenasas del Factor Inducible por Hipoxia/metabolismo , Procolágeno-Prolina Dioxigenasa/genética , Procolágeno-Prolina Dioxigenasa/metabolismo , Prolina/metabolismo , Pez Cebra/genética , Pez Cebra/metabolismo , Proteínas de Pez Cebra/genética , Proteínas de Pez Cebra/metabolismo , Eliminación de Gen , Oxígeno/metabolismoRESUMEN
The cytosolic RNA and DNA sensors initiate type I interferon signaling when binding to RNA or DNA. To effectively protect the host against virus infection and concomitantly avoid excessive interferonopathy at resting states, these sensors must be tightly regulated. However, the key molecular mechanisms regulating these sensors' activation remain elusive. Here, we identify PRMT3, a type I protein arginine methyltransferase, as a negative regulator of cytosolic RNA and DNA sensors. PRMT3 interacts with RIG-I, MDA5, and cGAS and catalyzes asymmetric dimethylation of R730 on RIG-I, R822 on MDA5, and R111 on cGAS. These modifications reduce RNA-binding ability of RIG-I and MDA5 as well as DNA-binding ability and oligomerization of cGAS, leading to the inhibition of downstream type I interferon production. Furthermore, mice with loss of one copy of Prmt3 or in vivo treatment of the PRMT3 inhibitor, SGC707, are more resistant to RNA and DNA virus infection. Our findings reveal an essential role of PRMT3 in the regulation of antiviral innate immunity and give insights into the molecular regulation of cytosolic RNA and DNA sensors' activation.
Asunto(s)
Arginina , Interferón Tipo I , Animales , Ratones , ARN/genética , Antivirales/farmacología , Inmunidad Innata , ADN/genética , Nucleotidiltransferasas/genética , Proteína-Arginina N-Metiltransferasas/genéticaRESUMEN
SIRT7 is a member of the sirtuin family proteins with nicotinamide adenine dinucleotide (NAD+)-dependent histone deacetylase activity, which can inhibit the activity of hypoxia-inducible factors independently of its enzymatic activity. However, the role of SIRT7 in affecting hypoxia signaling in vivo is still elusive. Here, we find that sirt7-null zebrafish are more resistant to hypoxic conditions, along with an increase of hypoxia-responsive gene expression and erythrocyte numbers, compared with their wildtype siblings. Overexpression of sirt7 suppresses the expression of hypoxia-responsive genes. Further assays indicate that sirt7 interacts with zebrafish hif-1αa, hif-1αb, hif-2αa, and hif-2αb to inhibit their transcriptional activity and mediate their protein degradation. In addition, sirt7 not only binds to the hypoxia responsive element of hypoxia-inducible gene promoters but also causes a reduction of H3K18Ac on these promoters. Sirt7 may regulate hypoxia-responsive gene expression through its enzymatic and nonenzymatic activities. This study provides novel insights into sirt7 function and sheds new light on the regulation of hypoxia signaling by sirt7.
Asunto(s)
Oxígeno , Sirtuinas , Proteínas de Pez Cebra , Pez Cebra , Animales , Subunidad alfa del Factor 1 Inducible por Hipoxia/genética , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Proteolisis , Sirtuinas/genética , Sirtuinas/metabolismo , Pez Cebra/genética , Proteínas de Pez Cebra/genética , Proteínas de Pez Cebra/metabolismo , Anaerobiosis , Oxígeno/metabolismoRESUMEN
In mammals, the signaling adaptor mitochondrial antiviral signaling protein (MAVS) is a critical determinant in antiviral innate immunity. However, because of the lack of in vivo data, the physiological function of zebrafish mavs in response to viral infection is still not determined. In this study, we demonstrate that the long splicing isoform of zebrafish mavs promotes IFN regulatory factor 3 signaling and NF-κB signaling. Overexpression of this isoform of mavs enhances cellular antiviral responses. Disruption of mavs in zebrafish attenuates survival ratio on challenge with spring viremia of carp virus. Consistently, the antiviral-responsive genes and inflammatory genes are significantly reduced, and the replication of spring viremia of carp virus is increased in mavs-null zebrafish. Therefore, we provide in vivo evidence to support that zebrafish mavs is essential for antiviral innate immunity, similar to mammalian MAVS.
Asunto(s)
Antivirales , Pez Cebra , Animales , Pez Cebra/metabolismo , Antivirales/metabolismo , Viremia , Inmunidad Innata , Isoformas de Proteínas/metabolismo , Mamíferos/metabolismo , Proteínas de Pez Cebra/genética , Proteínas de Pez Cebra/metabolismo , Proteínas Adaptadoras Transductoras de Señales/genética , Proteínas Adaptadoras Transductoras de Señales/metabolismoRESUMEN
The deubiquitinating enzyme OTUB1 possesses canonical deubiquitinase (DUB) activity and noncanonical, catalytic-independent activity, which has been identified as an essential regulator of diverse physiological processes. Posttranslational modifications of OTUB1 affect both its DUB activity and its noncanonical activity of binding to the E2 ubiquitin-conjugation enzyme UBC13, but further investigation is needed to characterize the full inventory of modifications to OTUB1. Here, we demonstrate that SET7, a lysine monomethylase, directly interacts with OTUB1 to catalyze OTUB1 methylation at lysine 122. This modification does not affect DUB activity of OTUB1 but impairs its noncanonical activity, binding to UBC13. Moreover, we found using cell viability analysis and intracellular reactive oxygen species assay that SET7-mediated methylation of OTUB1 relieves its suppressive role on ferroptosis. Notably, the methylation-mimic mutant of OTUB1 not only loses the ability to bind to UBC13 but also relieves its suppressive role on Tert-Butyl hydroperoxide-induced cell death and Cystine starvation/Erastin-induced cellular reactive oxygen species. Collectively, our data identify a novel modification of OTUB1 that is critical for inhibiting its noncanonical activity.
Asunto(s)
Enzimas Desubicuitinizantes , Ferroptosis , N-Metiltransferasa de Histona-Lisina , Enzimas Ubiquitina-Conjugadoras , Enzimas Desubicuitinizantes/metabolismo , Lisina/metabolismo , Unión Proteica , Especies Reactivas de Oxígeno/metabolismo , Ubiquitinación , Humanos , N-Metiltransferasa de Histona-Lisina/metabolismoRESUMEN
Spring viremia of carp virus (SVCV) is the causative agent of spring viremia of carp (SVC), an important infectious disease that causes high mortality in aquaculture cyprinids. How the host defends against SVCV infection and the underlying mechanisms are still elusive. In this study, we identify that a novel gene named maoc1 is induced by SVCV infection. maoc1-deficient zebrafish are more susceptible to SVCV infection, with higher virus replication and antiviral gene induction. Further assays indicate that maoc1 interacts with the P protein of SVCV to trigger P protein degradation through the autophagy-lysosomal pathway, leading to the restriction of SVCV propagation. These findings reveal a unique zebrafish defense machinery in response to SVCV infection. IMPORTANCE SVCV P protein plays an essential role in the virus replication and viral immune evasion process. Here, we identify maoc1 as a novel SVCV-inducible gene and demonstrate its antiviral capacity through attenuating SVCV replication, by directly binding to P protein and mediating its degradation via the autophagy-lysosomal pathway. Therefore, this study not only reveals an essential role of maoc1 in fighting against SVCV infection but also demonstrates an unusual host defense mechanism in response to invading viruses.
Asunto(s)
Autofagia , Enfermedades de los Peces , Lisosomas , Infecciones por Rhabdoviridae , Rhabdoviridae , Proteínas de Pez Cebra , Animales , Enfermedades de los Peces/genética , Enfermedades de los Peces/virología , Infecciones por Rhabdoviridae/veterinaria , Viremia/veterinaria , Pez Cebra , Proteínas de Pez Cebra/genética , Proteínas de Pez Cebra/fisiología , FosfoproteínasRESUMEN
Hypoxia-inducible factor (HIF)1α, a main transcriptional regulator of the cellular response to hypoxia, also plays important roles in oxygen homeostasis of aerobic organisms, which is regulated by multiple mechanisms. However, the full cellular response to hypoxia has not been elucidated. In this study, we found that expression of SMYD3, a methyltransferase, augments hypoxia signaling independent of its enzymatic activity. We demonstrated SMYD3 binds to and stabilizes HIF1α via co-immunoprecipitation and Western blot assays, leading to the enhancement of HIF1α transcriptional activity under hypoxia conditions. In addition, the stabilization of HIF1α by SMYD3 is independent of HIF1α hydroxylation by prolyl hydroxylases and the intactness of the von Hippel-Lindau ubiquitin ligase complex. Furthermore, we showed SMYD3 induces reactive oxygen species accumulation and promotes hypoxia-induced cell apoptosis. Consistent with these results, we found smyd3-null zebrafish exhibit higher hypoxia tolerance compared to their wildtype siblings. Together, these findings define a novel role of SMYD3 in affecting hypoxia signaling and demonstrate that SMYD3-mediated HIF1α stabilization augments hypoxia signaling, leading to the impairment of hypoxia tolerance.
Asunto(s)
N-Metiltransferasa de Histona-Lisina , Hipoxia , Metiltransferasas , Proteínas de Pez Cebra , Animales , Hipoxia/metabolismo , Subunidad alfa del Factor 1 Inducible por Hipoxia/genética , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Metiltransferasas/metabolismo , Transducción de Señal , Proteína Supresora de Tumores del Síndrome de Von Hippel-Lindau/genética , Proteína Supresora de Tumores del Síndrome de Von Hippel-Lindau/metabolismo , Pez Cebra/metabolismo , N-Metiltransferasa de Histona-Lisina/genética , N-Metiltransferasa de Histona-Lisina/metabolismo , Proteínas de Pez Cebra/genética , Proteínas de Pez Cebra/metabolismoRESUMEN
The signaling adaptor MAVS is a critical determinant in retinoic acid-inducible gene 1-like receptor signaling, and its activation is tightly controlled by multiple mechanisms in response to viral infection, including phosphorylation and ubiquitination. In this article, we demonstrate that zebrafish sirt5, one of the sirtuin family proteins, negatively regulates mavs-mediated antiviral innate immunity. Sirt5 is induced by spring viremia of carp virus (SVCV) infection and binds to mavs, resulting in attenuating phosphorylation and ubiquitination of mavs. Disruption of sirt5 in zebrafish promotes survival ratio after challenge with SVCV. Consistently, the antiviral responsive genes are enhanced, and the replication of SVCV is diminished in sirt5-dificient zebrafish. Therefore, we reveal a function of zebrafish sirt5 in the negative regulation of antiviral innate immunity by targeting mavs.
Asunto(s)
Sirtuinas , Pez Cebra , Proteínas Adaptadoras Transductoras de Señales/genética , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Animales , Antivirales , Inmunidad Innata , Fosforilación , Rhabdoviridae , Sirtuinas/metabolismo , Tretinoina/metabolismo , Ubiquitinación , Pez Cebra/metabolismo , Proteínas de Pez Cebra/genética , Proteínas de Pez Cebra/metabolismoRESUMEN
Retinoic acid-inducible-I (RIG-I), melanoma differentiation-associated gene 5 (MDA5), and cyclic GMP-AMP synthase (cGAS) genes encode essential cytosolic receptors mediating antiviral immunity against viruses. Here, we show that OTUD3 has opposing role in response to RNA and DNA virus infection by removing distinct types of RIG-I/MDA5 and cGAS polyubiquitination. OTUD3 binds to RIG-I and MDA5 and removes K63-linked ubiquitination. This serves to reduce the binding of RIG-I and MDA5 to viral RNA and the downstream adaptor MAVS, leading to the suppression of the RNA virus-triggered innate antiviral responses. Meanwhile, OTUD3 associates with cGAS and targets at Lys279 to deubiquitinate K48-linked ubiquitination, resulting in the enhancement of cGAS protein stability and DNA-binding ability. As a result, Otud3-deficient mice and zebrafish are more resistant to RNA virus infection but are more susceptible to DNA virus infection. These findings demonstrate that OTUD3 limits RNA virus-triggered innate immunity but promotes DNA virus-triggered innate immunity.
Asunto(s)
Infecciones por Virus ADN , Inmunidad Innata , Infecciones por Virus ARN , Proteasas Ubiquitina-Específicas , Animales , Proteína 58 DEAD Box/metabolismo , Infecciones por Virus ADN/inmunología , Virus ADN , Enzimas Desubicuitinizantes , Helicasa Inducida por Interferón IFIH1/metabolismo , Ratones , Nucleotidiltransferasas , Infecciones por Virus ARN/inmunología , Virus ARN , ARN Viral/metabolismo , Proteasas Ubiquitina-Específicas/metabolismo , Pez Cebra/metabolismoRESUMEN
As a main regulator of cellular responses to hypoxia, the protein stability of hypoxia-inducible factor (HIF)-1α is strictly controlled by oxygen tension dependent of PHDs-catalyzed protein hydroxylation and pVHL complex-mediated proteasomal degradation. Whether HIF-1α protein stability as well as its activity can be further regulated under hypoxia is not well understood. In this study, we found that OTUB1 augments hypoxia signaling independent of PHDs/VHL and FIH. OTUB1 binds to HIF-1α and depletion of OTUB1 reduces endogenous HIF-1α protein under hypoxia. In addition, OTUB1 inhibits K48-linked polyubiquitination of HIF-1α via its non-canonical inhibition of ubiquitination activity. Furthermore, OTUB1 promotes hypoxia-induced glycolytic reprogramming for cellular metabolic adaptation. These findings define a novel regulation of HIF-1α under hypoxia and demonstrate that OTUB1-mediated HIF-1α stabilization positively regulates HIF-1α transcriptional activity and benefits cellular hypoxia adaptation.