The Ebola virus VP35 protein functions as a type I IFN antagonist

Basler, Christopher F.; Wang, Xiuyan; Mühlberger, Elke; Volchkov, Viktor E.; Paragas, Jason; Klenk, Hans‐Dieter; Garcı́a-Sastre, Adolfo; Palese, Peter

doi:10.1073/pnas.220398297

Cited by 440 publications

(396 citation statements)

References 53 publications

Supporting

Mentioning

386

Contrasting

Order By: Relevance

“…28), with further investigations finding that IRF-3 and NF-B were also inhibited (29,30). This property of type I IFN antagonism has also been identified for Ebola virus VP35 protein (31), suggesting dual and possibly multiple roles for proteins encoded by small genome RNA viruses in cell interactions and immune evasion. TNF-␣ expression has been shown to be sensitive to in vitro infection by RRV alone (12), and this finding has been confirmed by this study (see Fig.…”

Section: Discussionmentioning

confidence: 61%

Suppression of lipopolysaccharide-induced antiviral transcription factor (STAT-1 and NF-κB) complexes by antibody-dependent enhancement of macrophage infection by Ross River virus

Mahalingam

Lidbury²

2002

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Section: Discussionmentioning

confidence: 61%

Suppression of lipopolysaccharide-induced antiviral transcription factor (STAT-1 and NF-κB) complexes by antibody-dependent enhancement of macrophage infection by Ross River virus

Mahalingam

Lidbury²

2002

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

“…dsRNA has long been recognized as a potent activator of host innate immune signaling that establishes an antiviral state (9,10), and the ability for Ebola VP35 to block these signals is well documented (3,15,16,23,26). Therefore, we tested the ability of wild type and central basic patch mutants of VP35 IID to bind heterologous dsRNA.…”

Section: Basic Residues Within the Vp35 Iid Sequence Are Highly Consementioning

confidence: 99%

“…Only VP35, and not any other Ebola protein, supports viral growth of a mutant influenza A virus that lacks the IFN suppressor protein NS1A, suggesting that VP35 also inhibits IFN activity (23). A bioinformatics study identified an 8-residue motif in VP35 that has 75% sequence identity to the influenza NS1A protein, including basic residues essential for binding of dsRNA by NS1 (21).…”

mentioning

confidence: 99%

Structure of the Ebola VP35 interferon inhibitory domain

Leung

Ginder

Fulton

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

145

195

View full text Add to dashboard Cite

Ebola viruses (EBOVs) cause rare but highly fatal outbreaks of viral hemorrhagic fever in humans, and approved treatments for these infections are currently lacking. The Ebola VP35 protein is multifunctional, acting as a component of the viral RNA polymerase complex, a viral assembly factor, and an inhibitor of host interferon (IFN) production. Mutation of select basic residues within the C-terminal half of VP35 abrogates its dsRNA-binding activity, impairs VP35-mediated IFN antagonism, and attenuates EBOV growth in vitro and in vivo. Because VP35 contributes to viral escape from host innate immunity and is required for EBOV virulence, understanding the structural basis for VP35 dsRNA binding, which correlates with suppression of IFN activity, is of high importance. Here, we report the structure of the C-terminal VP35 IFN inhibitory domain (IID) solved to a resolution of 1.4 Å and show that VP35 IID forms a unique fold. In the structure, we identify 2 basic residue clusters, one of which is important for dsRNA binding. The dsRNA binding cluster is centered on Arg-312, a highly conserved residue required for IFN inhibition. Mutation of residues within this cluster significantly changes the surface electrostatic potential and diminishes dsRNA binding activity. The high-resolution structure and the identification of the conserved dsRNA binding residue cluster provide opportunities for antiviral therapeutic design. Our results suggest a structure-based model for dsRNA-mediated innate immune antagonism by Ebola VP35 and other similarly constructed viral antagonists.crystal structure ͉ Ebola virus ͉ RNA binding E bola viruses (EBOVs) cause severe hemorrhagic fever characterized by fever, shock, coagulation defects, and impaired immunity (1, 2). These manifestations of infection are thought to reflect subversion of the innate immune system coupled with uncontrolled viral replication, particularly in macrophages and dendritic cells (3,4). EBOV infection of these cells enhances production of proinflammatory cytokines, such as TNF-␣ and IFN (IFN)-␥, and diminishes stimulation of T cell maturation by dendritic cells (3, 4). Like other negative-strand RNA viruses that impair both innate and adaptive immunity (e.g., influenza, rabies, and measles), EBOV suppresses host IFN activities to replicate, thus resulting in serious disease (5, 6). Only individuals who survive EBOV infection show appreciable amounts of viral-specific antibodies (7), suggesting that EBOV infections lead to shutdown of early immune responses and prevent activation of adaptive immune responses.Recognition of viral particles and viral RNA, including RNA modifications such as 5Ј-triphosphate (5Ј-ppp), by cytosolic pattern recognition receptor helicases RIG-I and MDA-5 leads to activation of transcription factors, including IFN regulatory factor-3 (IRF-3), IRF-7, NF-B, and AP-1 (8-12). These transcription factors in turn induce expression of a large number of cytokines, such as IFN-␣ and IFN-␤ (13). Activated IFN genes operate in both autocrine and paracrin...

show abstract

“…11 and 12). EBOV VP35 interacts with several components of innate antiviral defenses, including retinoic-acid inducible gene-I (RIG-I)-like receptor (RLR) pathways that lead to IFN production (13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24). These include inhibition of IFN production through double-stranded (ds)RNA sequestration and inhibition of IFN regulatory factor (IRF) 3/IRF7 phosphorylation by direct association with kinases that activate IRF3/IRF7, IKKe/TBK-1 (13,15,21,25).…”

mentioning

confidence: 99%

Structural basis for Marburg virus VP35–mediated immune evasion mechanisms

Ramanan

Edwards

Shabman

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

120

View full text Add to dashboard Cite

Filoviruses, marburgvirus (MARV) and ebolavirus (EBOV), are causative agents of highly lethal hemorrhagic fever in humans. MARV and EBOV share a common genome organization but show important differences in replication complex formation, cell entry, host tropism, transcriptional regulation, and immune evasion. Multifunctional filoviral viral protein (VP) 35 proteins inhibit innate immune responses. Recent studies suggest double-stranded (ds)RNA sequestration is a potential mechanism that allows EBOV VP35 to antagonize retinoic-acid inducible gene-I (RIG-I) like receptors (RLRs) that are activated by viral pathogen-associated molecular patterns (PAMPs), such as double-strandedness and dsRNA blunt ends. Here, we show that MARV VP35 can inhibit IFN production at multiple steps in the signaling pathways downstream of RLRs. The crystal structure of MARV VP35 IID in complex with 18-bp dsRNA reveals that despite the similar protein fold as EBOV VP35 IID, MARV VP35 IID interacts with the dsRNA backbone and not with blunt ends. Functional studies show that MARV VP35 can inhibit dsRNA-dependent RLR activation and interferon (IFN) regulatory factor 3 (IRF3) phosphorylation by IFN kinases TRAF family member-associated NFkb activator (TANK) binding kinase-1 (TBK-1) and IFN kB kinase e (IKKe) in cell-based studies. We also show that MARV VP35 can only inhibit RIG-I and melanoma differentiation associated gene 5 (MDA5) activation by double strandedness of RNA PAMPs (coating backbone) but is unable to inhibit activation of RLRs by dsRNA blunt ends (end capping). In contrast, EBOV VP35 can inhibit activation by both PAMPs. Insights on differential PAMP recognition and inhibition of IFN induction by a similar filoviral VP35 fold, as shown here, reveal the structural and functional plasticity of a highly conserved virulence factor.T he Filoviridae family of viruses, which includes marburgvirus (MARV) and ebolavirus (EBOV), can cause intermittent outbreaks that often result in high fatality rates (1). The family consists of five species of EBOV, Zaire, Reston, Sudan, Taï Forest, and Bundibugyo; one species of MARV; and a proposed genus Cuevavirus possessing a single species Lloviu cuevavirus (2). Despite overall similarities in genome size and organization, virion structure, and disease characteristics (3), EBOV and MARV exhibit important differences, including their strategies for immune evasion (4). For example, although EBOV viral protein (VP) 24 and MARV VP40 counter IFN signaling, neither MARV VP24 nor EBOV VP40 appears to function similarly to its corresponding counterparts with regard to immune evasion (5-10).Filoviruses also counteract innate immunity through the multifunctional VP35 proteins, which perform critical roles in viral RNA synthesis, virus assembly, and virus structure (reviewed in refs. 11 and 12). EBOV VP35 interacts with several components of innate antiviral defenses, including retinoic-acid inducible gene-I (RIG-I)-like receptor (RLR) pathways that lead to IFN production (13-24). These include inhibition of ...

show abstract

The Ebola virus VP35 protein functions as a type I IFN antagonist

Cited by 440 publications

References 53 publications

Suppression of lipopolysaccharide-induced antiviral transcription factor (STAT-1 and NF-κB) complexes by antibody-dependent enhancement of macrophage infection by Ross River virus

Suppression of lipopolysaccharide-induced antiviral transcription factor (STAT-1 and NF-κB) complexes by antibody-dependent enhancement of macrophage infection by Ross River virus

Structure of the Ebola VP35 interferon inhibitory domain

Structural basis for Marburg virus VP35–mediated immune evasion mechanisms

Contact Info

Product

Resources

About