RESUMEN
UV-induced DNA damage, a major risk factor for skin cancers, is primarily repaired by nucleotide excision repair (NER). UV radiation resistance-associated gene (UVRAG) is a tumor suppressor involved in autophagy. It was initially isolated as a cDNA partially complementing UV sensitivity in xeroderma pigmentosum (XP), but this was not explored further. Here we show that UVRAG plays an integral role in UV-induced DNA damage repair. It localizes to photolesions and associates with DDB1 to promote the assembly and activity of the DDB2-DDB1-Cul4A-Roc1 (CRL4(DDB2)) ubiquitin ligase complex, leading to efficient XPC recruitment and global genomic NER. UVRAG depletion decreased substrate handover to XPC and conferred UV-damage hypersensitivity. We confirmed the importance of UVRAG for UV-damage tolerance using a Drosophila model. Furthermore, increased UV-signature mutations in melanoma correlate with reduced expression of UVRAG. Our results identify UVRAG as a regulator of CRL4(DDB2)-mediated NER and suggest that its expression levels may influence melanoma predisposition.
Asunto(s)
Autofagia/efectos de la radiación , Daño del ADN , Reparación del ADN/efectos de la radiación , Proteínas de Unión al ADN/metabolismo , Melanoma Experimental/enzimología , Neoplasias Cutáneas/enzimología , Proteínas Supresoras de Tumor/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo , Rayos Ultravioleta , Animales , Proteínas Portadoras/genética , Proteínas Portadoras/metabolismo , Proteínas Cullin/genética , Proteínas Cullin/metabolismo , Proteínas de Unión al ADN/genética , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/enzimología , Drosophila melanogaster/genética , Drosophila melanogaster/efectos de la radiación , Activación Enzimática , Células HEK293 , Células HeLa , Humanos , Melanoma Experimental/genética , Melanoma Experimental/patología , Proteolisis , Interferencia de ARN , Retina/enzimología , Retina/efectos de la radiación , Transducción de Señal/efectos de la radiación , Neoplasias Cutáneas/genética , Neoplasias Cutáneas/patología , Factores de Tiempo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Transfección , Proteínas Supresoras de Tumor/genética , Ubiquitina-Proteína Ligasas/genética , UbiquitinaciónRESUMEN
OPINION STATEMENT: The primordial autophagy process, originally identified as a starvation response in baker's yeast, has since been shown to have a wide spectrum of functions other than survival. In many cases, it is accepted that autophagy operates as a key tumor suppressor mechanism that protects cells from adverse environmental cues by enforcing homeostasis and maintaining the functional and structural integrity of organelles. Paradoxically, heightened states of autophagy are also seen in some cancers, leading to the prevailing view that the pro-survival aspect of autophagy might be hijacked by some tumors to promote their fitness and pathogenesis. Notably, recent studies have revealed a broad range of cell-autonomous autophagy in reshaping tumor microenvironment and maintaining lineage integrity and immune homeostasis, calling for a renewed understanding of autophagy beyond its classical roles in cell survival. Here, we evaluate the increasing body of literature that argues the "double-edged" consequences of autophagy manipulation in cancer therapy, with a particular focus on highly plastic and mutagenic melanoma. We also discuss the caveats that must be considered when evaluating whether autophagy blockade is the effector mechanism of some anti-cancer therapy particularly associated with lysosomotropic agents. If autophagy proteins are to be properly exploited as targets for anticancer drugs, their diverse and complex roles should also be considered.
Asunto(s)
Antineoplásicos , Melanoma , Neoplasias , Humanos , Neoplasias/terapia , Melanoma/terapia , Melanoma/tratamiento farmacológico , Autofagia/fisiología , Antineoplásicos/uso terapéutico , Supervivencia Celular , Microambiente TumoralRESUMEN
RIG-I is a pattern recognition receptor that senses viral RNA and is crucial for host innate immune defense. Here, we describe a mechanism of RIG-I activation through amidotransferase-mediated deamidation. We show that viral homologs of phosphoribosylformylglycinamidine synthetase (PFAS), although lacking intrinsic enzyme activity, recruit cellular PFAS to deamidate and activate RIG-I. Accordingly, depletion and biochemical inhibition of PFAS impair RIG-I deamidation and concomitant activation. Purified PFAS and viral homolog thereof deamidate RIG-I in vitro. Ultimately, herpesvirus hijacks activated RIG-I to avoid antiviral cytokine production; loss of RIG-I or inhibition of RIG-I deamidation results in elevated cytokine production. Together, these findings demonstrate a surprising mechanism of RIG-I activation that is mediated by an enzyme.
Asunto(s)
Ligasas de Carbono-Nitrógeno con Glutamina como Donante de Amida-N/inmunología , ARN Helicasas DEAD-box/inmunología , Gammaherpesvirinae/inmunología , Evasión Inmune/genética , ARN Viral/inmunología , Proteínas Virales/inmunología , Amidas/metabolismo , Animales , Ligasas de Carbono-Nitrógeno con Glutamina como Donante de Amida-N/genética , Línea Celular , Citocinas/antagonistas & inhibidores , Citocinas/biosíntesis , Proteína 58 DEAD Box , ARN Helicasas DEAD-box/antagonistas & inhibidores , ARN Helicasas DEAD-box/genética , ARN Helicasas DEAD-box/metabolismo , Activación Enzimática , Fibroblastos/enzimología , Fibroblastos/inmunología , Fibroblastos/virología , Gammaherpesvirinae/genética , Regulación de la Expresión Génica , Células HEK293 , Humanos , Inmunidad Innata , Ratones , Imitación Molecular , ARN Interferente Pequeño/genética , ARN Interferente Pequeño/metabolismo , ARN Viral/genética , Receptores Inmunológicos , Transducción de Señal , Proteínas Virales/genéticaRESUMEN
Exciton behaviors including exciton formation and dissociation dynamics play an essential role in the optoelectronic performance of semiconductive materials but remain unexplored in semiconductive metal-organic frameworks (MOFs). Herein, we reveal that the exciton behaviors in semiconductive MOFs can be regulated by framework-guest interactions, a feature often not achievable in traditional inorganic or organic semiconductors. Incorporation of the electron-deficient molecule within the pores of a terbium-based semiconductive MOF (Tb2L2·4H2O·6DMF, L = TATAB3-, 4,4',4â³-s-triazine-1,3,5-triyltri-p-aminobenzoate, DMF = N,N-dimethylformamide) results in efficient energy transfer from the MOF skeleton to molecular acceptors, with a yield of up to 77.4%. This interaction facilitates distinctive exciton type conversion, giving rise to modified conductivity and photoelectric performance. We further fabricated a MOF-based X-ray detection device to demonstrate how the new architecture bolsters the optoelectronic efficiency, which outperforms the properties of parent semiconductive MOFs, with more than 60 times and 40 times enhancement of the photocurrent on-off ratio and detection sensitivity, respectively. With judiciously optimized exciton behaviors, the detection device exhibits a high sensitivity of 51.9 µC Gyair-1 cm-2 and records a charge carrier mobility-lifetime product of 1.12 × 10-3 cm2 V-1 among MOF-based X-ray detectors, which are competitive with values for commercially available detectors. These findings demonstrate a rational synthetic approach to designing exciton arrangements to improve the optoelectronic efficiency of semiconductive MOFs.
RESUMEN
Hybrid metal halide perovskites are extensively synthesized using p- and d-elements. However, the properties of hybrid halide perovskites involving 5f-elements are still elusive. Herein, we first report the semiconductive property of a uranium-bearing hybrid halide perovskite, [N(C2H5)4]2UCl6 (EAUCl). Single crystal X-ray crystallography demonstrates that EAUCl adopts a zero-dimensional molecular structure consisting of isolated [UCl6]2- anions and organic cations. The intrinsically semiconductive property endows EAUCl with obvious charge transport and photoconductivity, with a high carrier mobility lifetime (µτ) product of 9.91 × 10-4 cm2/V and a photocurrent on-off ratio of 380 under X-ray excitation. Theoretical calculations corroborate that the U 5f orbitals are involved in electron transitions and the formation of band structure.
RESUMEN
UV-induced cell pigmentation represents an important mechanism against skin cancers. Sun-exposed skin secretes α-MSH, which induces the lineage-specific transcriptional factor MITF and activates melanogenesis in melanocytes. Here, we show that the autophagic tumor suppressor UVRAG plays an integral role in melanogenesis by interaction with the biogenesis of lysosome-related organelles complex 1 (BLOC-1). This interaction is required for BLOC-1 stability and for BLOC-1-mediated cargo sorting and delivery to melanosomes. Absence of UVRAG dispersed BLOC-1 distribution and activity, resulting in impaired melanogenesis in vitro and defective melanocyte development in zebrafish in vivo. Furthermore, our results establish UVRAG as an important effector for melanocytes' response to α-MSH signaling as a direct target of MITF and reveal the molecular basis underlying the association between oncogenic BRAF and compromised UV protection in melanoma.
Asunto(s)
Melaninas/biosíntesis , Melanosomas/metabolismo , Pigmentación de la Piel/efectos de la radiación , Proteínas Supresoras de Tumor/metabolismo , Rayos Ultravioleta , Animales , Células HEK293 , Humanos , Melaninas/genética , Melanoma/genética , Melanoma/metabolismo , Melanosomas/genética , Factor de Transcripción Asociado a Microftalmía/genética , Factor de Transcripción Asociado a Microftalmía/metabolismo , Proteínas Proto-Oncogénicas B-raf/genética , Proteínas Proto-Oncogénicas B-raf/metabolismo , Proteínas Supresoras de Tumor/genética , Pez Cebra/genética , Pez Cebra/metabolismo , Proteínas de Pez Cebra/genética , Proteínas de Pez Cebra/metabolismoRESUMEN
Antibiotic resistance genes (ARGs) have attracted extensive attention as an emerging environmental contaminant potentially threatening humans. One of the main emission sources of ARGs is swine wastewater. In this study, integrated membrane filtration including ultrafiltration and two-stage reverse osmosis was conducted for swine wastewater treatment. The abundances of 16 target ARGs, which accounted for 72.64% of the total ARGs in swine wastewater according to metagenomic sequencing, were quantified by quantitative real-time PCR (qPCR) during each stage of the membrane filtration process. The results showed that integrated membrane filtration could reduce more than 99.0% of conventional pollutants and 99.79% of ARGs (from 3.02 × 108 copy numbers/mL to 6.45 × 105 copy numbers/mL). Principal component analysis (PCA) indicated that the removal efficiency of ARGs subtype by membrane filtration did not depend on ARGs type. However, strong correlations were found between ARGs and the wastewater quality indicators TP, SS and EC according to Cooccurrence patterns, indicating that ARG removal was closely associated with insoluble solid particles and soluble ions in swine wastewater. These results showed that membrane filtration could not only remove conventional pollutants such as nitrogen and phosphorus but also reduce the emerging pollutant of ARGs and decrease the risk of ARGs flowing into natural water.
Asunto(s)
Farmacorresistencia Microbiana/genética , Filtración/métodos , Genes Bacterianos , Purificación del Agua/métodos , Crianza de Animales Domésticos , Animales , Nitrógeno , Fósforo , Reacción en Cadena en Tiempo Real de la Polimerasa , Porcinos , Aguas Residuales/microbiología , Contaminantes del AguaRESUMEN
We disclose the intrinsic semiconducting properties of one of the largest mixed-valent uranium clusters, [H3 O+ ][UV (UVI O2 )8 (µ3 -O)6 (PhCOO)2 (Py(CH2 O)2 )4 (DMF)4 ] (Ph=phenyl, Py=pyridyl, DMF=N,N-dimethylformamide) (1). Single-crystal X-ray crystallography demonstrates that UV center is stabilized within a tetraoxo core surrounded by eight uranyl(VI) pentagonal bipyramidal centers. The oxidation states of uranium are substantiated by spectroscopic data and magnetic susceptibility measurement. Electronic spectroscopy and theory corroborate that UV species serve as electron donors and thus facilitate 1 being a n-type semiconductor. With the largest effective atomic number among all reported radiation-detection semiconductor materials, charge transport properties and photoconductivity were investigated under X-ray excitation for 1: a large on-off ratio of 500 and considerable charge mobility lifetime product of 2.3×10-4 â cm2 V-1 , as well as a high detection sensitivity of 23.4â µC Gyair -1 cm-2 .
RESUMEN
The potential applications of metal-organic cages (MOCs) are mostly achieved through specific host-guest interactions within their cavities. Electronic applications would require an effective electron transport pathway, which has been extensively studied in hybrid organic-inorganic materials with extended structures. These properties have not been considered for MOCs because cage-to-cage interactions in these materials have rarely been examined and are challenging to functionalize. We report here a previously unobserved actinide-based MOC assembled from four hexagonal-bipyramidal-coordinated uranyl ions and six bidentate flexible ligands. Remarkably, each isolated cage is further interlocked with six adjacent ones through mechanical bonds, resulting in the first case of a 0D â 3D f-element polycatenated metal-organic cage, SCU-14. Long-range π-π stacking extending throughout the structure is built via polycatenation, providing a visible carrier transmission path. SCU-14 is also an extremely rare case of an intrinsically semiconductive MOC with a wide band gap of 2.61 eV. Combined with the high X-ray attenuation efficiency, SCU-14 can effectively convert X-ray photons to electrical current signals and presents a promising sensitivity of 54.93 µC Gy-1 cm-2.
RESUMEN
Semiconductive metal-organic frameworks (MOFs) have emerged in applications such as chemical sensors, electrocatalysts, energy storage materials, and electronic devices. However, examples of semiconductive MOFs within flexible electronics have not been reported. We present flexible X-ray detectors prepared by thermoplastic dispersal of a semiconductive MOF (SCU-13) through a commercially available polymer, poly(vinylidene fluoride). The flexible detectors exhibit efficient X-ray-to-electric current conversion with enhanced charge-carrier mobility and low trap density compared to pelleted devices. A high X-ray detection sensitivity of 65.86â µCGyair -1 cm-2 was achieved, which outperforms other pelleted devices and commercial flexible X-ray detectors. We demonstrate that the MOF-based flexible detectors can be operated at multiple bending angles without a deterioration in detection performance. As a proof-of-concept, an X-ray phase contrast under bending conditions was constructed using a 5×5 pixelated MOF-based imager.
RESUMEN
A wide range of tunability in the physical parameters of a semiconductor used for X-ray detection is desirable to achieve targeted performance optimization. However, in a dense-phase semiconductor, fine-tuning one parameter often leads to unwanted changes in other parameters. Herein, the intrinsic openness in an open-framework semiconductor has been confirmed, for the first time, to be a key structural factor that weakens the mutual exclusivity of the adjustable physical parameters owing to a non-linear control mechanism. The controllable doping of S in a zeolitic In-Se host results in an optimal balance between resistivity, band gap, and carrier mobility, which finally results in an excellent X-ray detector with a high figure of merit for the mobility-lifetime product (7.12×10-4 â cm2 V-1 ); this value is superior to that of a commercial α-Se detector. The current strategy of choosing open-framework semiconductor materials opens a new window for targeting high-performance X-ray detection.
RESUMEN
The viral Bcl-2 homolog (vBcl2) of Kaposi's sarcoma-associated herpesvirus (KSHV) displays efficient antiapoptotic and antiautophagic activity through its central BH3 domain, which functions to prolong the life span of virus-infected cells and ultimately enhances virus replication and latency. Independent of its antiapoptotic and antiautophagic activity, vBcl2 also plays an essential role in KSHV lytic replication through its amino-terminal amino acids (aa) 11 to 20. Here, we report a novel molecular mechanism of vBcl2-mediated regulation of KSHV lytic replication. vBcl2 specifically bound the tegument protein open reading frame 55 (ORF55) through its amino-terminal aa 11 to 20, allowing their association with virions. Consequently, the vBcl2 peptide derived from vBcl2 aa 11 to 20 effectively disrupted the interaction between vBcl2 and ORF55, inhibiting the incorporation of the ORF55 tegument protein into virions. This study provides new insight into vBcl2's function in KSHV virion assembly that is separable from its inhibitory role in host apoptosis and autophagy.IMPORTANCE KSHV, an important human pathogen accounting for a large percentage of virally caused cancers worldwide, has evolved a variety of stratagems for evading host immune responses to establish lifelong persistent infection. Upon viral infection, infected cells can go through programmed cell death, including apoptosis and autophagy, which plays an effective role in antiviral responses. To counter the host response, KSHV vBcl2 efficiently blocks apoptosis and autophagy to persist for the life span of virus-infected cells. Besides its anti-programmed-cell-death activity, vBcl2 also interacts with the ORF55 tegument protein for virion assembly in infected cells. Interestingly, the vBcl2 peptide disrupts the vBcl2-ORF55 interaction and effectively inhibits KSHV virion assembly. This study indicates that KSHV vBcl2 harbors at least three genetically separable functions to modulate both host cell death signaling and virion production and that the vBcl2 peptide can be developed as an anti-KSHV therapeutic application.
Asunto(s)
Herpesvirus Humano 8/fisiología , Proteínas Oncogénicas/fisiología , Sistemas de Lectura Abierta , Proteínas Virales/fisiología , Ensamble de Virus , Apoptosis , Autofagia , Secuencia de Bases , Replicación del ADN , ADN Viral/genética , Expresión Génica , Técnicas de Inactivación de Genes , Genoma Viral , Células HEK293 , Herpesvirus Humano 8/genética , Humanos , Proteínas Oncogénicas/genética , Proteínas Virales/genéticaRESUMEN
Activation of pattern recognition receptors and proper regulation of downstream signaling are crucial for host innate immune response. Upon infection, the NF-κB and interferon regulatory factors (IRF) are often simultaneously activated to defeat invading pathogens. Mechanisms concerning differential activation of NF-κB and IRF are not well understood. Here we report that a MAVS variant inhibits interferon (IFN) induction, while enabling NF-κB activation. Employing herpesviral proteins that selectively activate NF-κB signaling, we discovered that a MAVS variant of ~50 kDa, thus designated MAVS50, was produced from internal translation initiation. MAVS50 preferentially interacts with TRAF2 and TRAF6, and activates NF-κB. By contrast, MAVS50 inhibits the IRF activation and suppresses IFN induction. Biochemical analysis showed that MAVS50, exposing a degenerate TRAF-binding motif within its N-terminus, effectively competed with full-length MAVS for recruiting TRAF2 and TRAF6. Ablation of the TRAF-binding motif of MAVS50 impaired its inhibitory effect on IRF activation and IFN induction. These results collectively identify a new means by which signaling events is differentially regulated via exposing key internally embedded interaction motifs, implying a more ubiquitous regulatory role of truncated proteins arose from internal translation and other related mechanisms.
Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/metabolismo , Factor 2 Asociado a Receptor de TNF/metabolismo , Factor 6 Asociado a Receptor de TNF/metabolismo , Secuencia de Aminoácidos , Humanos , Inductores de Interferón/inmunología , Interferones/metabolismo , FN-kappa B/metabolismo , Unión Proteica/fisiologíaRESUMEN
Enveloped viruses exploit the endomembrane system to enter host cells. Through a cascade of membrane-trafficking events, virus-bearing vesicles fuse with acidic endosomes and/or lysosomes mediated by SNAREs triggering viral fusion. However, the molecular mechanisms underlying this process remain elusive. Here, we found that UV-radiation resistance-associated gene (UVRAG), an autophagic tumor suppressor, is required for the entry of the prototypic negative-strand RNA virus, including influenza A virus and vesicular stomatitis virus, by a mechanism independent of IFN and autophagy. UVRAG mediates viral endocytic transport and membrane penetration through interactions with the class C vacuolar protein sorting (C-Vps) tethering complex and endosomal glutamine-containing SNAREs [syntaxin 7 (STX7), STX8, and vesicle transport through t-SNARE homolog 1B (Vti1b)], leading to the assembly of a fusogenic trans-SNARE complex involving vesicle-associated membrane protein (VAMP8), but not VAMP7. Indeed, UVRAG stimulates VAMP8 translocation to virus-bearing endosomes. Inhibition of VAMP8, but not VAMP7, significantly reduces viral entry. Our data indicate that UVRAG, in concert with C-Vps, regulates viral entry by assembling a specific fusogenic SNARE complex. Thus, UVRAG governs downstream viral entry, highlighting an important pathway capable of potential antiviral therapeutics.
Asunto(s)
Proteínas R-SNARE/metabolismo , Virus ARN/fisiología , Proteínas Supresoras de Tumor/metabolismo , Proteínas de Transporte Vesicular/metabolismo , Internalización del Virus , Análisis de Varianza , Animales , Western Blotting , Chlorocebus aethiops , Cricetinae , Citometría de Flujo , Técnica del Anticuerpo Fluorescente , Proteínas Fluorescentes Verdes/metabolismo , Células HEK293 , Células HeLa , Humanos , Inmunoprecipitación , Virus de la Influenza A/fisiología , Ratones , Microscopía Confocal , Microscopía Fluorescente , Células 3T3 NIH , Plásmidos/genética , Interferencia de ARN , ARN Interferente Pequeño/genética , Reacción en Cadena en Tiempo Real de la Polimerasa , Células Vero , Vesiculovirus/fisiologíaRESUMEN
UNLABELLED: Kaposi's sarcoma-associated herpesvirus (KSHV) evades host defenses through tight suppression of autophagy by targeting each step of its signal transduction: by viral Bcl-2 (vBcl-2) in vesicle nucleation, by viral FLIP (vFLIP) in vesicle elongation, and by K7 in vesicle maturation. By exploring the roles of KSHV autophagy-modulating genes, we found, surprisingly, that vBcl-2 is essential for KSHV lytic replication, whereas vFLIP and K7 are dispensable. Knocking out vBcl-2 from the KSHV genome resulted in decreased lytic gene expression at the mRNA and protein levels, a lower viral DNA copy number, and, consequently, a dramatic reduction in the amount of progeny infectious viruses, as also described in the accompanying article (A. Gelgor, I. Kalt, S. Bergson, K. F. Brulois, J. U. Jung, and R. Sarid, J Virol 89:5298-5307, 2015). More importantly, the antiapoptotic and antiautophagic functions of vBcl-2 were not required for KSHV lytic replication. Using a comprehensive mutagenesis analysis, we identified that glutamic acid 14 (E14) of vBcl-2 is critical for KSHV lytic replication. Mutating E14 to alanine totally blocked KSHV lytic replication but showed little or no effect on the antiapoptotic and antiautophagic functions of vBcl-2. Our study indicates that vBcl-2 harbors at least three important and genetically separable functions to modulate both cellular signaling and the virus life cycle. IMPORTANCE: The present study shows for the first time that vBcl-2 is essential for KSHV lytic replication. Removal of the vBcl-2 gene results in a lower level of KSHV lytic gene expression, impaired viral DNA replication, and consequently, a dramatic reduction in the level of progeny production. More importantly, the role of vBcl-2 in KSHV lytic replication is genetically separated from its antiapoptotic and antiautophagic functions, suggesting that the KSHV Bcl-2 carries a novel function in viral lytic replication.
Asunto(s)
Herpesvirus Humano 8/fisiología , Proteínas Oncogénicas/fisiología , Proteínas Virales/fisiología , Replicación Viral/fisiología , Secuencia de Aminoácidos , Sustitución de Aminoácidos , Apoptosis , Autofagia , Secuencia de Bases , Línea Celular , Replicación del ADN , ADN Viral/genética , Expresión Génica , Técnicas de Inactivación de Genes , Genoma Viral , Células HEK293 , Herpesvirus Humano 8/genética , Herpesvirus Humano 8/patogenicidad , Interacciones Huésped-Patógeno , Humanos , Proteínas Mitocondriales/antagonistas & inhibidores , Proteínas Mitocondriales/genética , Proteínas Mitocondriales/fisiología , Datos de Secuencia Molecular , Mutagénesis Sitio-Dirigida , Proteínas Oncogénicas/antagonistas & inhibidores , Proteínas Oncogénicas/genética , Proteínas Virales/antagonistas & inhibidores , Proteínas Virales/genética , Replicación Viral/genéticaRESUMEN
Gammaherpesviruses such as Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV, HHV-8) establish lifelong latency in their hosts and are associated with the development of several types of malignancies, including a subset of B cell lymphomas. These viruses are thought to co-opt the process of B cell differentiation to latently infect a fraction of circulating memory B cells, resulting in the establishment of a stable latency setpoint. However, little is known about how this infected memory B cell compartment is maintained throughout the life of the host. We have previously demonstrated that immature and transitional B cells are long-term latency reservoirs for murine gammaherpesvirus 68 (MHV68), suggesting that infection of developing B cells contributes to the maintenance of lifelong latency. During hematopoiesis, immature and transitional B cells are subject to B cell receptor (BCR)-mediated negative selection, which results in the clonal deletion of autoreactive B cells. Interestingly, numerous gammaherpesviruses encode homologs of the anti-apoptotic protein Bcl-2, suggesting that virus inhibition of apoptosis could subvert clonal deletion. To test this, we quantified latency establishment in mice inoculated with MHV68 vBcl-2 mutants. vBcl-2 mutant viruses displayed a marked decrease in the frequency of immature and transitional B cells harboring viral genome, but this attenuation could be rescued by increased host Bcl-2 expression. Conversely, vBcl-2 mutant virus latency in early B cells and mature B cells, which are not targets of negative selection, was remarkably similar to wild-type virus. Finally, in vivo depletion of developing B cells during chronic infection resulted in decreased mature B cell latency, demonstrating a key role for developing B cells in the maintenance of lifelong latency. Collectively, these findings support a model in which gammaherpesvirus latency in circulating mature B cells is sustained in part through the recurrent infection and vBcl-2-mediated survival of developing B cells.
Asunto(s)
Linfocitos B/virología , Gammaherpesvirinae/fisiología , Infecciones por Herpesviridae/inmunología , Proteínas Proto-Oncogénicas c-bcl-2/inmunología , Infecciones Tumorales por Virus/inmunología , Latencia del Virus/inmunología , Animales , Apoptosis/inmunología , Linfocitos B/citología , Western Blotting , Diferenciación Celular/inmunología , Supervivencia Celular/inmunología , Citometría de Flujo , Ratones , Ratones Endogámicos C57BL , Microscopía Fluorescente , Reacción en Cadena de la Polimerasa , Receptores de Antígenos de Linfocitos B/inmunologíaRESUMEN
Autophagy is a highly regulated membrane remodeling process that allows the lysosome-mediated degradation of cytoplasmic entities by sequestrating them in double-membrane autophagosomes. Autophagy is hence highly intertwined with the endocytic trafficking pathway, sharing similar molecular machinery. Atg14L, also known as Beclin 1-associated autophagy-related key regulator (Barkor), directly interacts with Beclin 1 through its coiled-coil domain and enhances phosphatidylinositol 3-phosphate kinase class III (PI3KC3) activity to induce autophagosome membrane nucleation, highlighting its essential role in the early stage of mammalian autophagy. Here, we report a novel function of Atg14L in the endocytic trafficking pathway wherein Atg14L binds to and colocalizes with the fusogenic SNARE effector protein Snapin to facilitate endosome maturation. Atg14L specifically binds to Snapin and this interaction effectively facilitates endosomal maturation without affecting autophagic cargo degradation. Consequently, atg14l knockdown significantly delayed the late stage of endocytic trafficking, as evidenced by the retarded kinetics of internalized surface receptor degradation. This phenotype was effectively complemented by wild-type Atg14L or Beclin 1-binding mutant, but not by its Snapin-binding mutant. Taken together, our study demonstrates that Atg14L functions as a multivalent trafficking effector that regulates endosome maturation as well as autophagosome formation, reflecting the complexity of the crosstalk between autophagic and endocytic vesicle trafficking in higher eukaryotes.
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Proteínas Adaptadoras del Transporte Vesicular , Proteínas Reguladoras de la Apoptosis , Endocitosis/genética , Proteínas de la Membrana , Proteínas de Transporte Vesicular , Proteínas Adaptadoras del Transporte Vesicular/genética , Proteínas Adaptadoras del Transporte Vesicular/metabolismo , Animales , Proteínas Reguladoras de la Apoptosis/genética , Proteínas Reguladoras de la Apoptosis/metabolismo , Autofagia/genética , Proteínas Relacionadas con la Autofagia , Beclina-1 , Fosfatidilinositol 3-Quinasas Clase III/metabolismo , Endosomas/genética , Endosomas/metabolismo , Fibroblastos/citología , Fibroblastos/metabolismo , Células HEK293 , Células HeLa , Humanos , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo , Ratones , Fagosomas/metabolismo , Unión Proteica , Transporte de Proteínas , Proteínas SNARE/genética , Proteínas SNARE/metabolismo , Proteínas de Transporte Vesicular/genética , Proteínas de Transporte Vesicular/metabolismoRESUMEN
Autophagy is an evolutionarily conserved 'self-eating' process. Although the genes essential for autophagy (named Atg) have been identified in yeast, the molecular mechanism of how Atg proteins control autophagosome formation in mammalian cells remains to be elucidated. Here, we demonstrate that Bif-1 (also known as Endophilin B1) interacts with Beclin 1 through ultraviolet irradiation resistance-associated gene (UVRAG) and functions as a positive mediator of the class III PI(3) kinase (PI(3)KC3). In response to nutrient deprivation, Bif-1 localizes to autophagosomes where it colocalizes with Atg5, as well as microtubule-associated protein light chain 3 (LC3). Furthermore, loss of Bif-1 suppresses autophagosome formation. Although the SH3 domain of Bif-1 is sufficient for binding to UVRAG, both the BAR and SH3 domains are required for Bif-1 to activate PI(3)KC3 and induce autophagosome formation. We also observed that Bif-1 ablation prolongs cell survival under starvation conditions. Moreover, knockout of Bif-1 significantly enhances the development of spontaneous tumours in mice. These findings suggest that Bif-1 joins the UVRAG-Beclin 1 complex as a potential activator of autophagy and tumour suppressor.
Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/metabolismo , Autofagia/fisiología , Proteínas/metabolismo , Proteínas Supresoras de Tumor/metabolismo , Proteínas Adaptadoras Transductoras de Señales/genética , Animales , Proteínas Reguladoras de la Apoptosis , Autofagia/genética , Beclina-1 , Células COS , Caspasa 3/metabolismo , Línea Celular , Chlorocebus aethiops , Proteínas Fluorescentes Verdes/genética , Proteínas Fluorescentes Verdes/metabolismo , Células HeLa , Humanos , Inmunoprecipitación , Ratones , Ratones Noqueados , Microscopía Confocal , Microscopía Fluorescente , Microscopía Inmunoelectrónica , Neoplasias/genética , Neoplasias/metabolismo , Neoplasias/patología , Fagosomas/genética , Fagosomas/metabolismo , Fagosomas/ultraestructura , Fosfatidilinositol 3-Quinasas/genética , Fosfatidilinositol 3-Quinasas/metabolismo , Proteínas/genética , Interferencia de ARN , Transfección , Proteínas Supresoras de Tumor/genéticaRESUMEN
Macroautophagy/autophagy has previously been regarded as simply a way for cells to deal with nutrient emergency. But explosive work in the last 15 years has given increasingly new knowledge to our understanding of this process. Many of the functions of autophagy that are unveiled from recent studies, however, cannot be reconciled with this conventional view of cell survival but, instead, point to autophagy being integrally involved at a deeper level of cell biology, playing a critical role in maintaining homeostasis and promoting an integrated stress/immune response. The new appreciation of the role of autophagy in the evolutionary trajectory of cancer and cancer interaction with the immune system provides a mechanistic framework for understanding the clinical benefits of autophagy-based therapies. Here, we examine current knowledge of the mechanisms and functions of autophagy in highly plastic and aggressive melanoma as a model disease of human malignancy, while highlighting emerging dimensions indicating that autophagy is at play beyond its classical face.Abbreviation: AMBRA1: autophagy and beclin 1 regulator 1; AMPK: AMP-activated protein kinase; ATF4: activating transcription factor 4; ATG: autophagy related; BRAF: B-Raf proto-oncogene, serine/threonine kinase; CAFs: cancer-associated fibroblasts; CCL5: C-C motif chemokine ligand 5; CQ: chloroquine; CRISPR: clustered regularly interspaced short palindromic repeats; CTLA4: cytotoxic T-lymphocyte associated protein 4; CTL: cytotoxic T lymphocyte; DAMPs: danger/damage-associated molecular patterns; EGFR: epidermal growth factor receptor; EIF2A/eIF2α: eukaryotic translation initiation factor 2A; EIF2AK3/PERK: eukaryotic translation initiation factor 2 alpha kinase 3; ER: endoplasmic reticulum; FITM2: fat storage inducing transmembrane protein 2; HCQ: hydroxychloroquine; ICB: immune checkpoint blockade; ICD: immunogenic cell death; LDH: lactate dehydrogenase; MAPK: mitogen-activated protein kinase; MTORC1: mechanistic target of rapamycin kinase complex 1; NDP52: nuclear dot protein 52; NFKB/NF-κ B: nuclear factor kappa B; NBR1: the neighbor of BRCA1; NK: natural killer; NRF1: nuclear respiratory factor 1; NSCLC: non-small-cell lung cancer; OPTN: optineurin; PDAC: pancreatic ductal adenocarcinoma; PDCD1/PD-1: programmed cell death 1; PPT1: palmitoyl-protein thioesterase 1; PTEN: phosphatase and tensin homolog; PTK2/FAK1: protein tyrosine kinase 2; RAS: rat sarcoma; SQSTM1/p62: sequestosome 1; STK11/LKB1: serine/threonine kinase 11; TAX1BP1: Tax1 binding protein 1; TFEB: transcription factor EB; TGFB/TGF-ß: transforming growth factor beta; TMB: tumor mutational burden; TME: tumor microenvironment; TSC1: TSC complex subunit 1; TSC2: TSC complex subunit 2; ULK1: unc-51 like autophagy activating kinase 1; UVRAG: UV radiation resistance associated.
Asunto(s)
Autofagia , Melanoma , Proto-Oncogenes Mas , Humanos , Autofagia/fisiología , Autofagia/genética , Melanoma/patología , Melanoma/metabolismo , Melanoma/genética , AnimalesRESUMEN
Non-conventional water recovery, recycling, and reuse have been considered imperative approaches to addressing water scarcity in China. The objective of this study was to evaluate the technical and economic feasibility of Water Reclamation Plants (WRP) based on an anaerobic-anoxic-oxic membrane bioreactor (A2O-MBR) system for unconventional water resource treatment and reuse in towns (domestic sewage and rainwater). Rainwater is collected and stored in the rainwater reservoir through the rainwater pipe network, and then transported to the WRP for treatment and reuse through the rainwater reuse pumping station during the peak water demand period. During a year of operation and evaluation process, a total of 610,000 cubic meters of rainwater were reused, accounting for 10.4 % of the treated wastewater. In the A2O-MBR operation, the average effluent concentrations for COD (chemical oxygen demand), NH4+-N (ammonium), TN (total nitrogen), and TP (total phosphorus) were 14.23 ± 4.07 mg/L, 0.22 ± 0.26 mg/L, 11.97 ± 1.54 mg/L, and 0.13 ± 0.09 mg/L, respectively. The effluent quality met standards suitable for reuse in industrial cooling water or for direct discharge. The WRP demonstrates a positive financial outlook, with total capital and operating costs totaling 0.16 $/m3. A comprehensive cost-benefit analysis indicates a positive net present value for the WRP, and the estimated annualized net profit is 0.024 $/m3. This research has achieved near-zero discharge of wastewater and effective allocation of rainwater resources across time and space.