Journal of Virology最新文献

{"title":"Antagonism of stress granules is key to SARS-CoV-2 infection and pathogenesis.","authors":"R Elias Alvarado, Jennifer Chen, Kumari G Lokugamage, Yiyang Zhou, Leah K Estes, Angelica L Morgan, Yani Ahearn, Xiangxue Deng, Lilin Lai, Arian Moayyed, William Meyers, Jessica A Plante, Ken S Plante, David H Walker, Xuping Xie, Mehul S Suthar, Bryan A Johnson, Vineet D Menachery","doi":"10.1128/jvi.00992-26","DOIUrl":"10.1128/jvi.00992-26","url":null,"abstract":"<p><p>Viruses must subvert host responses to facilitate successful infection. While most antiviral responses are associated with interferons, stress granules (SGs) are another barrier to viral infection by inducing translation arrest. To combat SG activity, viruses have evolved mechanisms to disrupt formation and disassemble these complexes. Our prior studies identified residues in SARS-CoV-2 NSP3 (Y138/F145) and nucleocapsid (F17) that independently antagonize SG activity. Disrupting these key residues in NSP3 or nucleocapsid attenuated viral replication, but only modestly impacted <i>in vivo</i> pathogenesis, suggesting overlap in SG antagonism partially compensates for the individual losses. In this study, we evaluated a SARS-CoV-2 mutant (YF/F17A) that combines the NSP3 and N mutations. We find that loss of both SG-antagonizing functions attenuates SARS-CoV-2 replication <i>in vitro</i>. While no changes are seen in type I interferon sensitivity, attenuation corresponds to increased induction of SGs. Importantly, the SARS-CoV-2 YF/F17A mutant attenuates significantly <i>in vivo,</i> with reduced viral replication, less weight loss, and limited immune pathology. Notably, infection with the YF/F17A mutant stimulated less interferon and inflammation. Despite these muted host responses, the YF/F17A mutant stimulated robust protection against subsequent challenge with WT SARS-CoV-2. Overall, the study highlights the importance of SG control for SARS-CoV-2 infection and offers a novel, interferon-independent target for vaccination and therapeutic treatment going forward.IMPORTANCEThis study demonstrates that SARS-CoV-2 uses multiple mechanisms to block host stress granules during infection. Knocking out both N- and NSP3-mediated antagonism of stress granules attenuates viral replication and disease caused by SARS-CoV-2. Importantly, while most therapeutics target key viral processes or induce interferon pathways, this study shows stress granule activation as a novel approach to attenuate and treat coronavirus infection.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0099226"},"PeriodicalIF":4.1,"publicationDate":"2026-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148906422","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A chimeric murine coronavirus with altered deISGylase and proteolytic activities exhibits attenuated viral pathogenesis.","authors":"Mudassir S Ali, Amornrat O'Brien, Enya Qing, Lucky Sarkar, Fernando R Moreira, Bridget S Banach, Timothy E O'Brien, Michaela U Gack, Susan C Baker","doi":"10.1128/jvi.00857-26","DOIUrl":"10.1128/jvi.00857-26","url":null,"abstract":"<p><p>All coronaviruses encode one or two multifunctional papain-like proteases (PLPs) with protease activity that cleaves the viral polyprotein, along with deubiquitinating (DUB) and deISGylase activities that remove ubiquitin and interferon-stimulated gene 15 (ISG15) from viral and host proteins. Studying the role of coronavirus deISGylase activity in viral infection and pathogenesis has been challenging due to the inability to generate a viable deISGylase-deficient coronavirus. To address this issue, we used a recently characterized PLP domain from human coronavirus HKU1 that has intact protease and DUB activity, but minimal deISGylase activity. Switching the HKU1 PLP2 domain with the mouse hepatitis virus strain A59 (MHV-A59) PLP2 domain allowed us to generate a viable chimeric virus, MHV-HP2, that replicated to high titers in cell culture. Analysis of the PLP activities of MHV-HP2 revealed that the virus was impaired in deISGylase activity, intact in its DUB activity, and delayed in proteolytic processing at early time points. Detailed analysis of MHV-HP2 replication kinetics revealed that the delay in proteolytic processing coincided with a transient replication delay in cell culture. This replication delay was not rescued by knockdown of ISG15, suggesting proteolytic delay rather than protein ISGylation drives the delay in replication. Importantly, we found that MHV-HP2 is attenuated for replication and pathogenesis <i>in vivo,</i> with infected mice showing more rapid clearance of MHV-HP2 and reduced evidence of liver damage and inflammation as compared to MHV-A59-infected mice. These results document the generation of a murine coronavirus with diminished deISGylase activity and altered protease activity that highlight the importance of coronavirus PLP in coronavirus pathogenesis.IMPORTANCECoronaviruses are adept at circumventing host antiviral defenses by encoding the multifunctional papain-like protease (PLP). PLP modulates the host cellular environment with its proteolytic, deubiquitinase, and deISGylase activities. Coronavirus deISGylase activity targets the host protein interferon-stimulated gene 15 (ISG15), which can be conjugated to host and viral proteins to promote an antiviral state. To assess the contribution of viral deISGylase activity to pathogenesis, we generated a chimeric mouse coronavirus lacking robust deISGylase activity. Characterization of the chimeric virus revealed that the virus was also inefficient in proteolytic processing. We determined that diminished deISGylase activity and altered PLP protease activity resulted in attenuated pathogenesis in a mouse model system, since mice infected with the chimeric virus exhibited rapid clearance of infection and less severe tissue damage as compared to infection with the parental virus. These results reveal that modulating coronavirus PLP deISGylase and proteolytic activities can reduce disease burden.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0085726"},"PeriodicalIF":4.1,"publicationDate":"2026-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149081231","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reverse genetics and comparative pathogenesis of Lone Star virus.","authors":"Dorcus C A Omoga, Curtis Witt, Henry Giesel, James M Bowen, Krista Gunter, Stephanie Pozuelos, Ryan F Relich, Benjamin Brennan, Natasha L Tilston","doi":"10.1128/jvi.01009-26","DOIUrl":"10.1128/jvi.01009-26","url":null,"abstract":"<p><p>Lone Star virus (LSV) is a bandavirus first isolated from <i>Amblyomma americanum</i> ticks in the United States and is phylogenetically related to severe fever with thrombocytopenia syndrome virus (SFTSV), Heartland virus (HRTV), and Bhanja virus, each of which has been associated with severe human disease. In contrast to these better-characterized bandaviruses, LSV remains poorly studied, and its pathogenic potential is not well defined. The recent detection of LSV RNA in the cerebrospinal fluid of an immunocompromised patient in Idaho, U.S., with fatal meningoencephalitis further highlights the need for experimental systems to investigate LSV biology. Here, we rescued recombinant LSV (rLSV) from cloned complementary DNA (cDNA) plasmids and characterized the virus. rLSV replicated similarly to the parental LSV isolate in mammalian cells and caused rapid, systemic, and lethal disease in IFNAR^-/- mice, with widespread detection of viral RNA (vRNA) across multiple tissues, hepatic and splenic pathology, and induction of inflammatory cytokines. In contrast, C57BL/6J mice controlled infection and exhibited no clinical disease. To place LSV within a broader comparative framework, we generated rSFTSV from cloned cDNA and compared rLSV, rSFTSV, and HRTV in cell culture and IFNAR^-/- mice. Our studies revealed distinct disease kinetics among these related tick-borne bandaviruses and showed that HRTV-induced immunity protected against homologous HRTV rechallenge and heterologous rSFTSV challenge, but not rLSV challenge. Together, these findings establish reverse-genetics platforms and small-animal models for comparative bandavirus studies, define key features of LSV pathogenesis, and place this neglected virus within a framework of related bandaviruses that differ in virulence and immunological overlap.IMPORTANCETick-borne bandaviruses include several viruses associated with severe human disease, yet many related viruses remain poorly characterized. Lone Star virus (LSV) was first isolated from <i>Amblyomma americanum</i> ticks decades ago, but experimental tools and animal models to study LSV infection have been lacking. Here, we generated a recombinant LSV and used it to define the outcome of infection in immunocompromised and immunocompetent mice. We show that LSV can cause rapid, systemic, and lethal disease when type I interferon signaling is absent, whereas immunocompetent mice restrict infection and remain clinically normal. By comparing LSV with Heartland virus and severe fever with thrombocytopenia syndrome virus, we also show that related tick-borne bandaviruses differ in disease kinetics and immune protection. These findings provide foundational tools for studying LSV and highlight the importance of experimentally characterizing neglected tick-borne viruses before their pathogenic potential is fully understood.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0100926"},"PeriodicalIF":4.1,"publicationDate":"2026-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148892198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"RABV P protein activates the GSK3β-NF-κB signaling pathway to promote viral replication by interacting with the host protein Snapin.","authors":"Yujie Bai, Yongsai Liu, Xiaoyu Wu, Hongli Jin, Zhiyuan Gong, Yumeng Song, Xingqi Liu, Zihang Gao, Zhenhong Guan, Pei Huang, Yuanyuan Li, Haili Zhang, Hualei Wang","doi":"10.1128/jvi.01006-26","DOIUrl":"10.1128/jvi.01006-26","url":null,"abstract":"<p><p>Rabies virus (RABV), a lethal neurotropic pathogen, relies on interaction with the host to sustain neuronal infection; however, how it balances replication with neuronal survival remains unclear. Here, we revealed Snapin, a neuronal trafficking regulator, to be a critical host factor co-opted by RABV to enhance neuroinvasion. We found that RABV infection upregulated Snapin expression in N2a cells, and Snapin could promote the replication of RABV CVS11 and SRV9 strains in a dose-dependent manner. Mechanistic studies demonstrated that RABV P protein interacts with the 37-78 aa domain of Snapin via its C-terminal domain (172-297 aa), recruits glycogen synthase kinase 3β (GSK3β) in a Snapin-dependent manner, and forms a tripartite complex. Upon complex formation, the phosphorylation level at the Tyr216 site of GSK3β is increased, leading to activation of the NF-κB pathway. This activation enhances viral replication by upregulating neuronal stability genes (<i>Septin2, B4gat1</i>, and <i>Disc1</i>) without inducing interferon responses. <i>In vivo</i> studies show that knockdown of Snapin in infected mice delays clinical symptom onset and improves host survival. This study uncovers a unique strategy wherein RABV exploits Snapin as a molecular scaffold linking P to GSK3β/NF-κB signaling, coupling viral replication to neuronal homeostasis. Our work identifies a host-dependent axis for therapeutic targeting in rabies and offers broader implications for understanding neurotropic pathogens utilizing analogous mechanisms.</p><p><strong>Importance: </strong>Rabies virus (RABV) depends on host factors to maintain neuronal infection while avoiding cell death, but the mechanisms balancing viral replication and neuronal survival are unclear. This study identifies Snapin as a critical host factor commandeered by RABV to enhance neuroinvasion. Upon RABV infection, Snapin is upregulated and subsequently hijacked by the C-terminal domain of the RABV P protein. This interaction recruits GSK3β in a Snapin-dependent manner, forming a tripartite complex that increases phosphorylation of GSK3β at Tyr216 and activates the NF-κB pathway. Such activation upregulates neuronal stability genes (<i>Septin2</i>, <i>B4gat1</i>, and <i>Disc1</i>), thereby promoting viral replication without eliciting interferon responses. <i>In vivo</i> functional validation further confirms that Snapin deficiency attenuates RABV pathogenicity and prolongs host survival. Collectively, our study highlights a Snapin-dependent GSK3β/NF-κB axis as a potential therapeutic target for rabies treatment.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0100626"},"PeriodicalIF":4.1,"publicationDate":"2026-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148968978","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The capsid proteins of orthoflavivirus are interchangeable for West Nile virus assembly.","authors":"Jing Wang, Bao-Di Shang, Cheng-Lin Deng, Xiao-Dan Li, Bo Zhang","doi":"10.1128/jvi.01227-26","DOIUrl":"10.1128/jvi.01227-26","url":null,"abstract":"<p><p>Orthoflavivirus virions consist of an envelope enclosing a nucleocapsid core. A critical step in orthoflavivirus assembly is the encapsidation of genomic RNA by the capsid protein to form the nucleocapsid. However, the molecular details of this process remain poorly understood, particularly whether capsid proteins bind genomic RNA through specific interactions. Here, we utilized West Nile virus (WNV) and dengue virus (DENV) as model systems to investigate heterologous genome RNA encapsidation. Employing a chimeric virus strategy, we demonstrated that the DENV-2 capsid protein can package WNV genomic RNA if two critical elements are preserved: <i>cis</i>-acting sequences essential for RNA synthesis and the cleavage site required for capsid maturation. Furthermore, by decoupling the WNV <i>cis</i>-acting elements from the capsid-coding sequence and replacing the WNV capsid protein with orthologous capsid proteins from other orthoflaviviruses, we provide direct virological evidence that orthoflavivirus capsid proteins package genomic RNAs in a non-sequence-specific manner. These findings advance our mechanistic understanding of orthoflavivirus genome packaging.IMPORTANCEThe encapsidation of genomic RNA by capsid proteins as the primary event in orthoflavivirus virion assembly is not well understood in current research; particularly, whether it involves specific packaging signals remains a question. The orthoflavivirus capsid protein plays a key role in both genome replication and viral particle assembly. Our comprehensive virological analyses reveal that orthoflavivirus capsid protein shows considerable interspecies packaging flexibility while critical replication and processing elements are preserved. These insights underscore a key aspect of orthoflavivirus biology: the conserved packaging function of capsid proteins across genus members is mediated by structural interactions, rather than sequence specificity.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0122726"},"PeriodicalIF":4.1,"publicationDate":"2026-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149039611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"UFMylation of SHBs increases protein stability by antagonizing ubiquitination and promotes virion production.","authors":"Shuxiang Wu, Yilin Huang, Jing Xu, Jie Li, Xiaohuang Lin, Xinjian Lin, Xu Lin","doi":"10.1128/jvi.01034-26","DOIUrl":"10.1128/jvi.01034-26","url":null,"abstract":"<p><p>Post-translational modifications orchestrate virus-host interactions, yet their roles in the hepatitis B virus (HBV) life cycle remain incompletely defined. The small hepatitis B surface antigen (SHBs)-the most abundant HBV protein-drives immune evasion, pathogenesis, and virion/subviral particle (SVP) production. Here, we identify UFL1, the E3 ligase of UFMylation, as a host factor that modifies and stabilizes SHBs by antagonizing its ubiquitination to potentiate HBV output and SHBs-driven pro-oncogenic activities. Using affinity purification-mass spectrometry, we discovered UFL1 as a SHBs interactor and validated the interaction by co-immunoprecipitation, confocal co-localization, and GST pull-down assays. <i>In vivo</i> and <i>in vitro</i> UFMylation assays demonstrated that UFL1 catalyzes SHBs' UFMylation. Site-directed mutagenesis mapped the modification to K122; the K122R mutant failed to undergo UFMylation. Cycloheximide chase and ubiquitination assays showed that UFMylation at K122 stabilizes SHBs by antagonizing TRIM21-mediated K48-linked polyubiquitination and proteasomal degradation. Functionally, UFL1 enhanced SHBs-driven hepatocellular carcinoma cell migration and endothelial tube formation, whereas UFL1 knockdown produced opposite effects. In HBV-producing cells, UFL1 increased intracellular and extracellular HBsAg and HBV virions, with no effects on HBV RNA, indicating post-translational control of HBsAg and virion/SVP production. These findings establish SHBs as, to our knowledge, the first HBV protein substrate of UFMylation and reveal a UFL1-SHBs axis that promotes SHBs stability, pathogenic functions, and HBV particle output. Targeting UFMylation or the UFL1-SHBs interface offers a host-directed strategy to reduce HBsAg and virion production and may inform therapeutic approaches for HBV infection and HBV-related liver disease.</p><p><strong>Importance: </strong>Chronic infection with hepatitis B virus (HBV) remains a major global health problem, in part because current treatments rarely reduce the viral surface protein that floods the blood and helps the virus persist. In this study, we asked how the most abundant viral surface protein-SHBs-is controlled inside cells. We discovered that UFL1 attaches a small \"molecular tag\" as UFM1 to this viral protein, and this tag protects the SHBs from the cell's disposal system. As a result, the increased SHBs promotes behaviors linked to liver disease progression, and cells release more virion/SVPs. When we prevented this tagging event or changed a single amino acid on the SHBs so it could not be tagged, the protein became unstable and was degraded, and virus output dropped. Thus, to our knowledge, SHBs is the first identified HBV protein substrate of UFMylation, suggesting targeting the UFL1-SHBs interface may reduce HBsAg and virion production and inform HBV therapy.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0103426"},"PeriodicalIF":4.1,"publicationDate":"2026-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149017191","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"PRRSV Nsp9 hijacks BNIP3-mediated autophagy to provide membrane platforms for viral replication complexes.","authors":"Heyou Yi, Shaojun Wang, Guijie Guo","doi":"10.1128/jvi.01314-26","DOIUrl":"10.1128/jvi.01314-26","url":null,"abstract":"<p><p>Porcine reproductive and respiratory syndrome virus (PRRSV) is a major pathogen threatening the global swine industry. The viral nonstructural protein 9 (Nsp9) harbors RNA-dependent RNA polymerase activity and acts as a core component of the viral replication complex, yet its interplay with host factors remains incompletely understood. In this study, we identified the mitochondrial protein BCL2 interacting protein 3 (BNIP3) as a specific binding partner of Nsp9. This interaction is mediated by the transmembrane (TM) domain of BNIP3 and the N-terminal 1-449 region of Nsp9. Functional assays demonstrated that BNIP3 facilitates PRRSV replication via its TM domain and LC3-interacting region (LIR). Mechanistically, BNIP3 recruits Nsp9 to mitochondria, where Nsp9 blocks autophagic flux and triggers incomplete mitophagy. This process leads to the accumulation of BNIP3-associated autophagic membranes, which serve as platforms for viral replication complex assembly. Moreover, simultaneous knockdown of BNIP3 and ATG7 results in further suppression of viral replication compared to knockdown of either gene alone. Rescue experiments showed that BNIP3 overexpression partially restored viral replication in ATG7-deficient cells, while ATG7 overexpression failed to rescue the replication defect caused by BNIP3 knockdown, indicating that BNIP3 possesses ATG7-independent platform functions. Collectively, our findings reveal that PRRSV hijacks BNIP3 to reprogram autophagy and generate membrane platforms for replication, which may serve as a promising target for antiviral development.IMPORTANCEPorcine reproductive and respiratory syndrome virus (PRRSV) is one of the most economically significant viral pathogens affecting the global swine industry, yet the specific host factors that support viral replication remain incompletely defined. In this study, we identify BNIP3, a known mitochondrial protein, as a previously unrecognized interactor of the PRRSV RNA-dependent RNA polymerase Nsp9. We demonstrate that PRRSV Nsp9 exploits BNIP3 to block autophagic flux and create a specialized membrane microenvironment that serves as a membrane platform for viral replication complex assembly. Our findings reveal a mechanism by which PRRSV, a positive-sense RNA virus, utilizes a mitophagy receptor to generate replication-permissive membrane platforms, which advances our understanding of how viruses manipulate autophagy. The identification of BNIP3 as a critical host factor that promotes viral replication and the elucidation of its membrane platform function open new avenues for understanding PRRSV replication and may inform the development of novel antiviral strategies.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0131426"},"PeriodicalIF":4.1,"publicationDate":"2026-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149039568","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"BTX-A51 treatment modulates host innate immune responses via NF-κB and β-catenin signaling during Rift Valley fever virus infection <i>in vitro</i>.","authors":"Rafaela Flor, Timothy Stocker, Kaylee Petraccione, Maryna Akhrymuk, Brittany N Heath, Ivan Akhrymuk, Caitlin M Woodson, Kylene Kehn-Hall","doi":"10.1128/jvi.01042-26","DOIUrl":"10.1128/jvi.01042-26","url":null,"abstract":"<p><p>Rift Valley fever virus (RVFV) is a zoonotic and mosquito-borne hemorrhagic pathogen of high pandemic potential, endemic to most countries in Africa. It most severely causes disease in small domestic ruminants and is transmitted to humans. RVFV has been declared a priority pathogen by the World Health Organization for vaccine and therapeutic development. Outbreaks of this virus are known to cause great disturbances to the economy, agriculture, food availability, and healthcare system of local communities. No U.S. FDA-approved vaccines or therapeutics exist for the prevention or treatment of RVFV. Here, we used BTX-A51, an anticancer drug and casein kinase-1 (CK1) inhibitor, as a pharmacological tool to investigate the role of CK1 in regulating innate immune signaling during RVFV infection. The results show that CK1 inhibition via BTX-A51 dampened NF-κB-mediated signaling by blocking different steps in the cascade that require CK1 phosphorylation for signal progression. Consequently, this reduced translocation of p65 to the nucleus and transcriptional activation of pro-inflammatory cytokines and enzymes. Additionally, BTX-A51 treatment influenced the β-catenin pathway, resulting in a significant increase in β-catenin protein levels and β-catenin colocalization with p65. Delayed BTX-A51 treatment retained its impact on cytokine gene expression and partially rescued cells from RVFV-induced cell death. Our data suggest that CK1 inhibition influences both RVFV replication and host innate immune signaling, suggesting a relationship between the NF-κB and β-catenin pathways during RVFV infection. These findings identify CK1-mediated signaling as a potential target for host-directed therapeutic strategies aimed at limiting excessive virus-induced inflammation.IMPORTANCERift Valley fever virus (RVFV) is a zoonotic and mosquito-borne pathogen of high pandemic risk, affecting ruminants and humans. Disease outbreaks cause great health and economic disruptions to communities across the African continent, being famously known for its \"abortion storms.\" Casein kinase 1 (CK1) is a host kinase ubiquitously present in eukaryotic cells and involved in multiple pathways, such as NF-κB-mediated inflammation and β-catenin signaling. Both NF-κB and β-catenin signaling are altered in RVFV-infected cells. This manuscript tests the ability of BTX-A51, a CK1 inhibitor, to limit viral replication and inflammatory signaling. BTX-A51 acted concomitantly on the NF-κB and β-catenin pathways to reduce proinflammatory signaling in RVFV-infected cells. Due to many mechanisms of infection being conserved across the Bunyavirales order, these findings also create the potential for BTX-A51 treatment to be tested against different viruses as a tool for pandemic preparedness.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0104226"},"PeriodicalIF":4.1,"publicationDate":"2026-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148912445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Low-pH-induced conformational changes in the spike protein promote porcine deltacoronavirus infection by enhancing viral binding efficiency to the porcine aminopeptidase receptor.","authors":"Ruiming Yu, Liping Zhang, Peng Zhou, Zhongwang Zhang, Yingjie Bai, Dongsheng Wang, Ya Liu, Xinru Wang, Gang Du, Ligang Yuan, Huichen Guo, Li Pan, Xinsheng Liu","doi":"10.1128/jvi.01168-26","DOIUrl":"10.1128/jvi.01168-26","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Porcine deltacoronavirus (PDCoV) is a critical enteric pathogen causing severe diarrhea in neonatal piglets, with fecal-oral transmission as its primary route. However, the molecular mechanism underlying PDCoV adaptation to the acidic gastric environment of hosts remains elusive. Here, we demonstrate that low-pH pretreatment (pH 4.0), mimicking the gastric niche of suckling piglets, significantly enhances PDCoV infectivity in porcine intestinal epithelial IPEC-J2 cells, as shown by elevated viral attachment, replication, and progeny titers. Accordingly, neutralization of gastric acid in piglets effectively attenuates PDCoV infection and pathogenicity &lt;i&gt;in vivo&lt;/i&gt;. Mechanistically, acidic pH induces functionally important conformational rearrangements of the PDCoV spike (S) protein, which markedly increases its binding affinity for the cellular receptor porcine aminopeptidase N (pAPN), with the dissociation constant (KD) decreasing from 20.20 μM at pH 7.2 to 1.69 μM at pH 4.0. We solved the high-resolution cryo-electron microscopy (cryo-EM) structure of the PDCoV S protein under acidic conditions, representing the first deltacoronavirus S structure determined at low pH. Structural comparison with the neutral-pH closed conformation revealed that low pH drives a 14° outward rotation of the S1 C-terminal receptor-binding domain, reducing inter-domain interactions within the trimeric head and generating an intermediate activated conformation between the fully closed and fully open states, while the S2 fusion core remains structurally conserved. This pH-dependent conformational priming is shared by alpha- and deltacoronaviruses with intra-subunit S1 domain packing, which is distinct from the endosomal pH regulation of membrane fusion in betacoronaviruses, and represents an evolutionary adaptation to fecal-oral transmission. Our findings challenge the canonical view of gastric acid solely as a host defense barrier, uncover a preactivation role of the host physiological environment in viral infection, and provide new insights into enteric coronavirus biology, as well as novel targets for prevention and control strategies.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Importance: &lt;/strong&gt;Porcine deltacoronavirus (PDCoV), an emerging porcine enteric coronavirus, poses a serious threat to the swine industry and exhibits potential for cross-species transmission. This study demonstrated that the low-pH environment of the porcine stomach induces specific conformational changes in the PDCoV S protein, thereby maximizing the exposure of its receptor-binding domain, enhancing its binding to the host receptor, and promoting infection of intestinal epithelial cells. Our findings revealed that gastric acid functions not only as a physiological barrier but also as a key \"molecular switch\" that initiates PDCoV infection and is essential in enabling PDCoV to exploit the host physiological environment and complete its life cycle. These results provide new insights into the precise regulatory ","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0116826"},"PeriodicalIF":4.1,"publicationDate":"2026-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148912474","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"African swine fever virus A151R protein antagonizes the antiviral activity of barrier-to-autointegration factor (BAF) by targeting its dsDNA-binding activity.","authors":"Kepalee Saeng-Chuto, Zhigang Wang, Kaylee Bargeron, Matthew S Wiebe","doi":"10.1128/jvi.00988-26","DOIUrl":"10.1128/jvi.00988-26","url":null,"abstract":"<p><p>Barrier-to-autointegration factor (BAF) is a ubiquitous double-stranded DNA-binding protein that compacts DNA and can restrict poxvirus replication in the cytoplasm. BAF antiviral DNA-binding activity is tightly regulated by dynamic phosphorylation mediated by viral and cellular enzymes. For example, vaccinia virus counteracts BAF by encoding the B1 kinase, which phosphorylates BAF and abrogates its DNA-binding activity. Some DNA viruses, such as African swine fever virus (ASFV), undergo cytoplasmic replication but appear to lack a B1-like kinase. Interestingly, ASFV encodes A151R, a viral protein recently found to stably interact with BAF. Here, we demonstrate that A151R is capable of counteracting the antiviral properties of BAF. Structural modeling indicates that A151R is not a protein kinase and does not phosphorylate BAF but instead directly targets its double-stranded DNA-binding interface. This interaction enhances genome replication and progeny production of a B1-deficient virus. Mechanistically, A151R markedly impairs BAF DNA binding and disrupts its dimerization, a key requirement for high-affinity DNA association. Importantly, disruption of the A151R-BAF interaction abolishes these effects and restores BAF antiviral function. In addition, expression of the unphosphorylatable BAF mutant, which normally exhibits strong chromatin association, was redistributed to the cytoplasm in the presence of A151R, further supporting phosphorylation-independent regulation of BAF-DNA association. In conclusion, our findings support a previously unrecognized mechanism by which ASFV A151R disables BAF antiviral activity by obscuring its DNA-binding interface and inhibiting DNA binding in a phosphorylation-independent manner.IMPORTANCEDNA viruses replicating in the cytoplasm must overcome host intrinsic defenses to ensure productive replication, yet the mechanisms underlying their antagonism of the DNA-binding antiviral factor BAF remain incompletely understood. Here, we identify African swine fever virus (ASFV) A151R as a novel viral regulator that disables BAF by targeting its double-stranded DNA-binding interface rather than altering its phosphorylation state. We demonstrate that A151R impairs BAF DNA binding, disrupts its dimerization, and promotes viral DNA accumulation and progeny production in a BAF-dependent manner. Importantly, this activity requires A151R-BAF interaction and is independent of BAF phosphorylation status. Our findings reveal a previously unrecognized strategy employed by ASFV to neutralize host DNA-binding restriction factors and expand the molecular framework of BAF-mediated antiviral defense.</p>","PeriodicalId":17583,"journal":{"name":"Journal of Virology","volume":" ","pages":"e0098826"},"PeriodicalIF":4.1,"publicationDate":"2026-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148944252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}