RESUMEN
Increasing evidence has suggested that the HIV-1 capsid enters the nucleus in a largely assembled, intact form. However, not much is known about how the cone-shaped capsid interacts with the nucleoporins (NUPs) in the nuclear pore for crossing the nuclear pore complex. Here, we elucidate how NUP153 binds HIV-1 capsid by engaging the assembled capsid protein (CA) lattice. A bipartite motif containing both canonical and noncanonical interaction modules was identified at the C-terminal tail region of NUP153. The canonical cargo-targeting phenylalanine-glycine (FG) motif engaged the CA hexamer. By contrast, a previously unidentified triple-arginine (RRR) motif in NUP153 targeted HIV-1 capsid at the CA tri-hexamer interface in the capsid. HIV-1 infection studies indicated that both FG- and RRR-motifs were important for the nuclear import of HIV-1 cores. Moreover, the presence of NUP153 stabilized tubular CA assemblies in vitro. Our results provide molecular-level mechanistic evidence that NUP153 contributes to the entry of the intact capsid into the nucleus.
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Infecciones por VIH , Seropositividad para VIH , VIH-1 , Humanos , Proteínas de la Cápside/metabolismo , Cápside/metabolismo , VIH-1/metabolismo , Transporte Activo de Núcleo Celular , Proteínas de Complejo Poro Nuclear/metabolismo , Infecciones por VIH/metabolismo , Poro Nuclear/metabolismoRESUMEN
A short, 14-amino-acid segment called SP1, located in the Gag structural protein1, has a critical role during the formation of the HIV-1 virus particle. During virus assembly, the SP1 peptide and seven preceding residues fold into a six-helix bundle, which holds together the Gag hexamer and facilitates the formation of a curved immature hexagonal lattice underneath the viral membrane2,3. Upon completion of assembly and budding, proteolytic cleavage of Gag leads to virus maturation, in which the immature lattice is broken down; the liberated CA domain of Gag then re-assembles into the mature conical capsid that encloses the viral genome and associated enzymes. Folding and proteolysis of the six-helix bundle are crucial rate-limiting steps of both Gag assembly and disassembly, and the six-helix bundle is an established target of HIV-1 inhibitors4,5. Here, using a combination of structural and functional analyses, we show that inositol hexakisphosphate (InsP6, also known as IP6) facilitates the formation of the six-helix bundle and assembly of the immature HIV-1 Gag lattice. IP6 makes ionic contacts with two rings of lysine residues at the centre of the Gag hexamer. Proteolytic cleavage then unmasks an alternative binding site, where IP6 interaction promotes the assembly of the mature capsid lattice. These studies identify IP6 as a naturally occurring small molecule that promotes both assembly and maturation of HIV-1.
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VIH-1/metabolismo , Fosfatos de Inositol/metabolismo , Virión/metabolismo , Ensamble de Virus , Arginina/metabolismo , Cápside/química , Cápside/metabolismo , Cristalografía por Rayos X , VIH-1/química , VIH-1/genética , Técnicas In Vitro , Lisina/metabolismo , Modelos Moleculares , Simulación de Dinámica Molecular , Virión/química , Virión/genética , Productos del Gen gag del Virus de la Inmunodeficiencia Humana/química , Productos del Gen gag del Virus de la Inmunodeficiencia Humana/metabolismoRESUMEN
In this Letter, the Protein Data Bank (PDB) accessions were incorrectly listed as '6BH5, 6BHT and 6BHS' instead of '6BHR, 6BHT and 6BHS'; this has been corrected online.
RESUMEN
Reverse transcription, an essential event in the HIV-1 life cycle, requires deoxynucleotide triphosphates (dNTPs) to fuel DNA synthesis, thus requiring penetration of dNTPs into the viral capsid. The central cavity of the capsid protein (CA) hexamer reveals itself as a plausible channel that allows the passage of dNTPs into assembled capsids. Nevertheless, the molecular mechanism of nucleotide import into the capsid remains unknown. Employing all-atom molecular dynamics (MD) simulations, we established that cooperative binding between nucleotides inside a CA hexamer cavity results in energetically favorable conditions for passive translocation of dNTPs into the HIV-1 capsid. Furthermore, binding of the host cell metabolite inositol hexakisphosphate (IP6) enhances dNTP import, while binding of synthesized molecules like benzenehexacarboxylic acid (BHC) inhibits it. The enhancing effect on reverse transcription by IP6 and the consequences of interactions between CA and nucleotides were corroborated using atomic force microscopy, transmission electron microscopy, and virological assays. Collectively, our results provide an atomistic description of the permeability of the HIV-1 capsid to small molecules and reveal a novel mechanism for the involvement of metabolites in HIV-1 capsid stabilization, nucleotide import, and reverse transcription.
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Cápside/metabolismo , VIH-1/metabolismo , Replicación Viral/fisiología , Cápside/química , Cápside/fisiología , Proteínas de la Cápside/genética , Replicación del ADN/fisiología , ADN Viral/metabolismo , Células HEK293 , VIH-1/genética , Interacciones Huésped-Patógeno/fisiología , Humanos , Simulación de Dinámica Molecular , Nucleótidos/metabolismo , Permeabilidad , Ácido Fítico/análisis , Ácido Fítico/metabolismo , Virión/genética , Ensamble de Virus/fisiología , Replicación Viral/genéticaRESUMEN
Retrovirus assembly is driven by the multidomain structural protein Gag. Interactions between the capsid domains (CA) of Gag result in Gag multimerization, leading to an immature virus particle that is formed by a protein lattice based on dimeric, trimeric, and hexameric protein contacts. Among retroviruses the inter- and intra-hexamer contacts differ, especially in the N-terminal sub-domain of CA (CANTD). For HIV-1 the cellular molecule inositol hexakisphosphate (IP6) interacts with and stabilizes the immature hexamer, and is required for production of infectious virus particles. We have used in vitro assembly, cryo-electron tomography and subtomogram averaging, atomistic molecular dynamics simulations and mutational analyses to study the HIV-related lentivirus equine infectious anemia virus (EIAV). In particular, we sought to understand the structural conservation of the immature lentivirus lattice and the role of IP6 in EIAV assembly. Similar to HIV-1, IP6 strongly promoted in vitro assembly of EIAV Gag proteins into virus-like particles (VLPs), which took three morphologically highly distinct forms: narrow tubes, wide tubes, and spheres. Structural characterization of these VLPs to sub-4Å resolution unexpectedly showed that all three morphologies are based on an immature lattice with preserved key structural components, highlighting the structural versatility of CA to form immature assemblies. A direct comparison between EIAV and HIV revealed that both lentiviruses maintain similar immature interfaces, which are established by both conserved and non-conserved residues. In both EIAV and HIV-1, IP6 regulates immature assembly via conserved lysine residues within the CACTD and SP. Lastly, we demonstrate that IP6 stimulates in vitro assembly of immature particles of several other retroviruses in the lentivirus genus, suggesting a conserved role for IP6 in lentiviral assembly.
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Anemia Infecciosa Equina/metabolismo , Productos del Gen gag/química , Productos del Gen gag/metabolismo , Virus de la Anemia Infecciosa Equina/fisiología , Ácido Fítico/metabolismo , Virión/fisiología , Secuencia de Aminoácidos , Animales , Tomografía con Microscopio Electrónico , Anemia Infecciosa Equina/virología , Productos del Gen gag/genética , Infecciones por VIH/metabolismo , Infecciones por VIH/virología , VIH-1/genética , VIH-1/fisiología , VIH-1/ultraestructura , Caballos , Interacciones Huésped-Patógeno , Virus de la Anemia Infecciosa Equina/química , Virus de la Anemia Infecciosa Equina/genética , Virus de la Anemia Infecciosa Equina/ultraestructura , Alineación de Secuencia , Virión/genética , Virión/ultraestructura , Ensamble de Virus , Productos del Gen gag del Virus de la Inmunodeficiencia Humana/química , Productos del Gen gag del Virus de la Inmunodeficiencia Humana/genética , Productos del Gen gag del Virus de la Inmunodeficiencia Humana/metabolismoRESUMEN
The host factor protein TRIM5α plays an important role in restricting the host range of HIV-1, interfering with the integrity of the HIV-1 capsid. TRIM5 triggers an antiviral innate immune response by functioning as a capsid pattern recognition receptor, although the precise mechanism by which the restriction is imposed is not completely understood. Here we used an integrated magic-angle spinning nuclear magnetic resonance and molecular dynamics simulations approach to characterize, at atomic resolution, the dynamics of the capsid's hexameric and pentameric building blocks, and the interactions with TRIM5α in the assembled capsid. Our data indicate that assemblies in the presence of the pentameric subunits are more rigid on the microsecond to millisecond timescales than tubes containing only hexamers. This feature may be of key importance for controlling the capsid's morphology and stability. In addition, we found that TRIM5α binding to capsid induces global rigidification and perturbs key intermolecular interfaces essential for higher-order capsid assembly, with structural and dynamic changes occurring throughout the entire CA polypeptide chain in the assembly, rather than being limited to a specific protein-protein interface. Taken together, our results suggest that TRIM5α uses several mechanisms to destabilize the capsid lattice, ultimately inducing its disassembly. Our findings add to a growing body of work indicating that dynamic allostery plays a pivotal role in capsid assembly and HIV-1 infectivity.
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Proteínas de la Cápside/metabolismo , Cápside/metabolismo , VIH-1/metabolismo , Proteínas/metabolismo , Secuencia de Aminoácidos , Animales , Sitios de Unión , Cápside/química , Cápside/ultraestructura , Proteínas de la Cápside/química , Proteínas de la Cápside/genética , Clonación Molecular , Escherichia coli/genética , Escherichia coli/metabolismo , Expresión Génica , Vectores Genéticos/química , Vectores Genéticos/metabolismo , VIH-1/genética , VIH-1/ultraestructura , Humanos , Macaca mulatta , Espectroscopía de Resonancia Magnética/métodos , Simulación de Dinámica Molecular , Unión Proteica , Conformación Proteica en Hélice alfa , Conformación Proteica en Lámina beta , Dominios y Motivos de Interacción de Proteínas , Proteínas/química , Proteínas/genética , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Alineación de Secuencia , Homología de Secuencia de Aminoácido , Ubiquitina-Proteína LigasasRESUMEN
Endometriosis is a common estrogen-dependent inflammatory disease characterized by the presence of endometrial-like tissue outside the uterine cavity, which causes infertility and pelvic pain. Polymorphisms in MALAT1 have been demonstrated to play crucial roles in many diseases. However, the roles of MALAT1 polymorphisms in the etiology of endometriosis have not been well documented. We genotyped three MALAT1 polymorphisms in 555 endometriosis patients and 535 female control participants using quantitative polymerase chain reaction with TaqMan probes. To estimate the associations between MALAT1 polymorphisms and endometriosis risk, an unconditional logistic regression model was conducted to calculate an odds ratio (OR) and the 95% confidence interval (CI), adjusting for age, abortion history, number of deliveries, Body Mass Index (BMI), and The International Federation of Gynecology and Obstetrics (FIGO) stage. We found that the MALAT1 rs591291 C > T polymorphism significantly enhanced endometriosis risk (heterogeneous: adjusted OR = 1.36, 95% CI = 1.00-1.85, P = 0.050; homogenous: adjusted OR = 1.55, 95% CI = 1.03-2.33, P = 0.037; dominant: adjusted OR = 1.41, 95% CI = 1.05-1.88, P = 0.021). In stratification analyses, these associations were more predominant in the patients younger than 35 years old, with a relatively high number of deliveries and with a BMI between 25 and 29.9. Compared with wild-type CCG haplotype carriers, individuals with TCC haplotypes had a higher risk of developing endometriosis. The MALAT1 rs591291 C > T polymorphism was associated with a significant increase in endometriosis risk.
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Endometriosis/genética , ARN Largo no Codificante/genética , Adulto , Alelos , Estudios de Casos y Controles , China , Femenino , Predisposición Genética a la Enfermedad , Genotipo , Haplotipos , Humanos , Persona de Mediana Edad , Polimorfismo de Nucleótido Simple , Adulto JovenRESUMEN
Ebola virus (EBOV) is a human pathogen with the ability to cause hemorrhagic fever and bleeding diathesis in hosts. The life cycle of EBOV depends on its nucleocapsid. The Ebola nucleocapsid consists of a helical assembly of nucleoproteins (NPs) encapsidating single-stranded viral RNA (ssRNA). Knowledge of the molecular determinants of Ebola nucleocapsid stability is essential for the development of therapeutics against EBOV. However, large degrees of freedom associated with the Ebola nucleocapsid helical assembly pose a computational challenge, thereby limiting the previous simulation studies to the level of monomers. In the present work, we have performed all atom molecular dynamics (MD) simulations of the helical assembly of EBOV nucleoproteins in the absence and presence of ssRNA. We found that ssRNA is essential for maintaining structural integrity of the nucleocapsid. Other molecular determinants observed to stabilize the nucleocapsid include NP-RNA and NP-NP interactions and ion distributions. Additionally, the structural and dynamical behavior of the nucleocapsid monomer depends on its position in the helical assembly. NP monomers present on the longitudinal edges of the helical tube are more exposed, flexible, and have weaker NP-NP interactions than those residing in the center. This work provides key structural features stabilizing the nucleocapsid that may serve as therapeutic targets.
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Ebolavirus/química , Simulación de Dinámica Molecular , Nucleocápside/análisis , HumanosRESUMEN
Under the background of "double carbon", exploring the growth path of green logistics and enhancing the driving force of technological innovation is the urgent need of our country to comply with the green transformation of its economy and realize high-quality economic growth. Taking the panel data of 30 Chinese provinces from 2010 to 2020 as the sample, the green logistics index evaluation system is constructed based on the driver-press-state-impact-response (DPSIR) theoretical framework, and the green economic efficiency of each province in the sample period is measured by using the non-expected output Super- Slacks-based measure (SBM) model, and by constructing the panel vector autoregressive (PVAR) model including technological innovation is used to systematically elaborate the dynamic influence paths among the three. The study found that: China's green economy, technological innovation, and green logistics all have their own mechanisms for growth, which will gradually diminish over time. In the near and long term, green logistics will promote technological innovations and the evolution of a green economy, but there is a lag in the long-term benefits of green logistics on technological progress. In the short term, technological innovation does not lend support to the growth of a green economy, but over time, the impact of technological innovation on the growth of that economy will shift from negative to positive. This shows that improving technological innovation capability is an important path for green logistics to promote green economic efficiency. The findings of the study provide a basis for decision making to achieve the emission reduction target and improve the efficiency of the green economy.
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BACKGROUND: Type 2 diabetes is often linked with osteoporosis (T2DOP), a condition that accelerates bone degeneration and increases the risk of fractures. Unlike conventional menopausal osteoporosis, the diabetic milieu exacerbates the likelihood of fractures and osteonecrosis. In particular poliumoside (Pol), derived from Callicarpa kwangtungensis Chun, has shown promising anti-oxidant and anti-inflammatory effects. Yet, its influence on T2DOP remains to be elucidated. PURPOSE: The focus of this study was to elucidate the influence of Pol in HGHF-associated ferroptosis and its implications in T2DOP. STUDY DESIGN: A murine model of T2DOP was established using a minimal dosage of streptozotocin (STZ) through intraperitoneal infusion combined with a diet high in fat and sugar. Concurrently, to mimic the diabetic condition in a lab environment, bone mesenchymal stem cells (BMSCs) were maintained in a high-glucose and high-fat (HGHF) setting. METHODS: The impact of Pol on BMSCs in an HGHF setting was determined using methods, such as BODIPY-C11, FerroOrange staining, mitochondrial functionality evaluations, and Western blot methodologies, coupled with immunoblotting and immunofluorescence techniques. To understand the role of Pol in a murine T2DOP model, techniques including micro-CT, hematoxylin and eosin (H&E) staining, dual-labeling with calcein-alizarin red, and immunohistochemistry were employed for detailed imaging and histological insights. RESULTS: Our findings suggest that Pol acts against HGHF-induced bone degradation and ferroptosis, as evidenced by an elevation in glutathione (GSH) and a decline in malondialdehyde (MDA) levels, lipid peroxidation, and mitochondrial reactive oxygen species (ROS). Furthermore, Pol treatment led to increased bone density, enhanced GPX4 markers, and reduced ROS in the distal femur region. On investigating the underlying mechanism of action, it was observed that Pol triggers the Nrf2/GPX4 pathway, and the introduction of lentivirus-Nrf2 negates the beneficial effects of Pol in HGHF-treated BMSCs. CONCLUSION: Pol is effective in treating T2DOP by activating the Nrf2/GPX4 signaling pathway to inhibit ferroptosis.
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Ácidos Cafeicos , Diabetes Mellitus Tipo 2 , Ferroptosis , Glicósidos , Osteoporosis , Animales , Ratones , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Factor 2 Relacionado con NF-E2 , Especies Reactivas de Oxígeno , Osteoporosis/tratamiento farmacológico , Osteoporosis/prevención & controlRESUMEN
Introduction: Understanding the seasonality of vegetation growth is important for maintaining sustainable development of grassland livestock systems over the Tibetan Plateau (TP). Current knowledge of changes in the seasonality of TP grasslands is restricted to spring and autumn phenology, with little known about the date of peak vegetation growth, the most relevant quantity for grassland productivity. Methods: We investigate the shifts of the date of peak vegetation growth and its climatic controls for the alpine grasslands over the TP during 2001-2020 using a framework based on the law of minimum, which is based on the assumption that peak vegetation growth would be consistent with the peak timing of the most limiting climatic resource. Results: The date of peak vegetation growth over the TP advanced by 0.81 days decade-1 during 2001-2020. This spring-ward shift mainly occurs in the semi-humid eastern TP, where the peak growth date tracks the advancing peak precipitation, and shifted towards the timing of peak temperature. The advancing peak growth over the eastern TP significantly stimulated the ecosystem production by 1.99 gCm-2 year-1 day-1 during 2001-2020, while this positive effect weakened from 3.02 gCm-2 year-1 day-1 during 2000s to 1.25 gCm-2 year-1 day-1 during 2010s. Discussion: Our results highlighted the importance of water availability in vegetation growth over the TP, and indicated that the TP grassland is moving towards a tipping point of transition from thermal-constrained to water-constrained ecosystem under the rapid warming climate.
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Osteoporosis is a prevalent bone metabolic disease in menopause, and long-term medication is accompanied by serious side effects. Ginger, a food spice and traditional medicine with ancient history, exhibits the potential to alleviate osteoporosis in preclinical experiments, whereas its complex composition leads to ambiguous pharmacological mechanisms. The purpose of this study was to investigate the effect and mechanism of Ced in estrogen-deficient osteoporosis, a sesquiterpene alcohol recently discovered from Ginger with multiple pharmacological properties. RANKL was stimulated BMM (bone marrow macrophages) differentiation into osteoclasts in vitro. And the osteoclast activity and number were assessed by TRAcP and SEM. We found that Ced mitigated RANKL-induced osteoclastogenesis by descending the ROS content and obstructing NFATc1, NF-κB, and MAPK signaling. Also, Ced-mediated anti-osteolytic property was found in ovariectomized mice by Micro-CT scanning and histological staining. Summarily, our works demonstrated the anti-osteoporotic potential of Cedrol in Ginger for the first time, which also offered more pharmacological evidence for Ginger as food or medicine used for bone metabolic disease.
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Osteoporosis , Zingiber officinale , Femenino , Animales , Ratones , Especies Reactivas de Oxígeno/metabolismo , Osteoclastos , Osteoporosis/tratamiento farmacológico , Osteoporosis/metabolismo , Osteogénesis , FN-kappa B/metabolismo , Estrógenos/metabolismo , Ligando RANK/metabolismo , Factores de Transcripción NFATC/metabolismo , Diferenciación CelularRESUMEN
HIV-1 capsid (CA) stability is important for viral replication. E45A and P38A mutations enhance and reduce core stability, thus impairing infectivity. Second-site mutations R132T and T216I rescue infectivity. Capsid lattice stability was studied by solving seven crystal structures (in native background), including P38A, P38A/T216I, E45A, E45A/R132T CA, using molecular dynamics simulations of lattices, cryo-electron microscopy of assemblies, time-resolved imaging of uncoating, biophysical and biochemical characterization of assembly and stability. We report pronounced and subtle, short- and long-range rearrangements: (1) A38 destabilized hexamers by loosening interactions between flanking CA protomers in P38A but not P38A/T216I structures. (2) Two E45A structures showed unexpected stabilizing CANTD-CANTD inter-hexamer interactions, variable R18-ring pore sizes, and flipped N-terminal ß-hairpin. (3) Altered conformations of E45Aa α9-helices compared to WT, E45A/R132T, WTPF74, WTNup153, and WTCPSF6 decreased PF74, CPSF6, and Nup153 binding, and was reversed in E45A/R132T. (4) An environmentally sensitive electrostatic repulsion between E45 and D51 affected lattice stability, flexibility, ion and water permeabilities, electrostatics, and recognition of host factors.
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Proteínas de la Cápside , VIH-1 , Proteínas de la Cápside/genética , VIH-1/genética , Microscopía por Crioelectrón , Cápside , BiofisicaRESUMEN
Richter's Transformation (RT) is a poorly understood and fatal progression of chronic lymphocytic leukemia (CLL) manifesting histologically as diffuse large B-cell lymphoma. Protein arginine methyltransferase 5 (PRMT5) is implicated in lymphomagenesis, but its role in CLL or RT progression is unknown. We demonstrate herein that tumors uniformly overexpress PRMT5 in patients with progression to RT. Furthermore, mice with B-specific overexpression of hPRMT5 develop a B-lymphoid expansion with increased risk of death, and Eµ-PRMT5/TCL1 double transgenic mice develop a highly aggressive disease with transformation that histologically resembles RT; where large-scale transcriptional profiling identifies oncogenic pathways mediating PRMT5-driven disease progression. Lastly, we report the development of a SAM-competitive PRMT5 inhibitor, PRT382, with exclusive selectivity and optimal in vitro and in vivo activity compared to available PRMT5 inhibitors. Taken together, the discovery that PRMT5 drives oncogenic pathways promoting RT provides a compelling rationale for clinical investigation of PRMT5 inhibitors such as PRT382 in aggressive CLL/RT cases.
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Leucemia Linfocítica Crónica de Células B , Linfoma de Células B Grandes Difuso , Animales , Ratones , Leucemia Linfocítica Crónica de Células B/genética , Leucemia Linfocítica Crónica de Células B/patología , Linfoma de Células B Grandes Difuso/patologíaRESUMEN
Actin polymerization dynamics regulated by actin-binding proteins are essential for various cellular functions. The cofilin family of proteins are potent regulators of actin severing and filament disassembly. The structural basis for cofilin-isoform-specific severing activity is poorly understood as their high-resolution structures in complex with filamentous actin (F-actin) are lacking. Here, we present the atomic-resolution structure of the muscle-tissue-specific isoform, cofilin-2 (CFL2), assembled on ADP-F-actin, determined by magic-angle-spinning (MAS) NMR spectroscopy and data-guided molecular dynamics (MD) simulations. We observe an isoform-specific conformation for CFL2. This conformation is the result of a unique network of hydrogen bonding interactions within the α2 helix containing the non-conserved residue, Q26. Our results indicate F-site interactions that are specific between CFL2 and ADP-F-actin, revealing mechanistic insights into isoform-dependent F-actin disassembly.
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Actinas , Cofilina 2/química , Citoesqueleto de Actina/metabolismo , Factores Despolimerizantes de la Actina/metabolismo , Actinas/metabolismo , Adenosina Difosfato/metabolismo , Cofilina 1/metabolismo , Cofilina 2/metabolismo , Humanos , Espectroscopía de Resonancia Magnética , Unión Proteica , Isoformas de Proteínas/metabolismoRESUMEN
HIV-1 replication is durably controlled without antiretroviral therapy (ART) in certain infected individuals called elite controllers (ECs). These individuals express specific human leukocyte antigens (HLA) that tag HIV-infected cells for elimination by presenting viral epitopes to CD8+ cytotoxic T-lymphocytes (CTL). In HIV-infected individuals expressing HLA-B27, CTLs primarily target the viral capsid protein (CA)-derived KK10 epitope. While selection of CA mutation R264K helps HIV-1 escape this potent CTL response, the accompanying fitness cost severely diminishes virus infectivity. Interestingly, selection of a compensatory CA mutation S173A restores HIV-1 replication. However, the molecular mechanism(s) underlying HIV-1 escape from this ART-free virus control by CTLs is not fully understood. Here, we report that the R264K mutation-associated infectivity defect arises primarily from impaired HIV-1 DNA integration, which is restored by the S173A mutation. Unexpectedly, the integration defect of the R264K variant was also restored upon depletion of the host cyclophilin A. These findings reveal a nuclear crosstalk between CA and HIV-1 integration as well as identify a previously unknown role of cyclophilin A in viral DNA integration. Finally, our study identifies a novel immune escape mechanism of an HIV-1 variant escaping a CA-directed CTL response.
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We aimed to investigate the biological roles of Argonaute 3 (AGO3) in cervical cancer. RNA profiles containing 306 cervical cancer tissues and 13 normal samples revealed that AGO3 was significantly up-regulated in cervical cancer, and the expression of AGO3 was negatively associated with the outcome of cervical cancer patients. Cell proliferation and transwell assays showed that the depletion of AGO3 markedly inhibited cervical cancer cell growth and mobility. Importantly, we detected that knockdown of AGO3 exerted suppressive effect on cellular behaviors via inactivating Wnt/ß-catenin signaling pathway. Collectively, we conclude that AGO3 is a novel tumor promoter in cervical cancer and has a potential to be a drug target and prognostic predictor of cervical cancer patients.
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Proteínas Argonautas/metabolismo , Neoplasias del Cuello Uterino/metabolismo , Neoplasias del Cuello Uterino/patología , Proteínas Wnt/metabolismo , beta Catenina/metabolismo , Proteínas Argonautas/genética , Línea Celular , Ensayos de Migración Celular , Supervivencia Celular , Cuello del Útero/citología , Femenino , Regulación Neoplásica de la Expresión Génica , Humanos , Transducción de Señal , Proteínas Wnt/genética , beta Catenina/genéticaRESUMEN
Base excision repair (BER) acts upon the most important mechanism of the DNA repair system, protecting DNA stability and integrity from the mutagenic and cytotoxic effects. Multiple researches have indicated that single-nucleotide polymorphisms (SNPs) in the BER-related gene may be associated with the susceptibility of ovarian cancer. However, the results are controversial. In this two-center case-control study, 19 potentially functional SNPs in six BER-related genes (hOGG1, APE1, PARP1, FEN1, LIG3 and XRCC1) was genotyped in 196 ovarian cancer cases and 272 cancer-free controls. And, their associations with ovarian cancer risk were assessed by unconditional logistic regression analyses. We found that PARP1 rs8679 and hOGG1 rs293795 polymorphisms were associated with a decreased risk of ovarian cancer under dominant model (adjusted OR=0.39, 95% CI=0.17-0.90, P=0.026; and adjusted OR=0.36, 95% CI=0.13-0.99, P=0.049, respectively). Stratification analysis demonstrated that this association was more pronounced in the subgroups of lower BMI and patients with early menarche and serous carcinoma. Moreover, LIG3 rs4796030 AA/AC variant genotypes performed an increased risk of ovarian cancer under recessive model (adjusted OR=1.54, 95% CI=1.01-2.35, P=0.046), especially in the subgroups of higher BMI, early clinic stage and the carcinoma at the left. These results suggested that PARP1, hOGG1 and LIG3 polymorphisms might impact on the risk of ovarian cancer. However, more researches with larger and different ethnic populations are warranted to support our findings.
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The viral capsid plays essential roles in HIV replication and is a major platform engaging host factors. To overcome challenges in study native capsid structure, we used the perfringolysin O to perforate the membrane of HIV-1 particles, thus allowing host proteins and small molecules to access the native capsid while improving cryoelectron microscopy image quality. Using cryoelectron tomography and subtomogram averaging, we determined the structures of native capsomers in the presence and absence of inositol hexakisphosphate (IP6) and cyclophilin A and constructed an all-atom model of a complete HIV-1 capsid. Our structures reveal two IP6 binding sites and modes of cyclophilin A interactions. Free energy calculations substantiate the two binding sites at R18 and K25 and further show a prohibitive energy barrier for IP6 to pass through the pentamer. Our results demonstrate that perfringolysin O perforation is a valuable tool for structural analyses of enveloped virus capsids and interactions with host cell factors.