scholarly journals Proteomic Discovery of VEEV E2-Host Partner Interactions Identifies GRP78 Inhibitor HA15 as a Potential Therapeutic for Alphavirus Infections

Pathogens ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 283
Author(s):  
Michael D. Barrera ◽  
Victoria Callahan ◽  
Ivan Akhrymuk ◽  
Nishank Bhalla ◽  
Weidong Zhou ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Protein Trafficking ◽  
Viral Protein ◽  
Sindbis Virus ◽  
Encephalitis Virus ◽  
Host Proteins ◽  
Atp Production ◽  
Equine Encephalitis Virus ◽  
E2 Glycoprotein ◽  
Late Stages

Alphaviruses are a genus of the Togaviridae family and are widely distributed across the globe. Venezuelan equine encephalitis virus (VEEV) and eastern equine encephalitis virus (EEEV), cause encephalitis and neurological sequelae while chikungunya virus (CHIKV) and Sindbis virus (SINV) cause arthralgia. There are currently no approved therapeutics or vaccines available for alphaviruses. In order to identify novel therapeutics, a V5 epitope tag was inserted into the N-terminus of the VEEV E2 glycoprotein and used to identify host-viral protein interactions. Host proteins involved in protein folding, metabolism/ATP production, translation, cytoskeleton, complement, vesicle transport and ubiquitination were identified as VEEV E2 interactors. Multiple inhibitors targeting these host proteins were tested to determine their effect on VEEV replication. The compound HA15, a GRP78 inhibitor, was found to be an effective inhibitor of VEEV, EEEV, CHIKV, and SINV. VEEV E2 interaction with GRP78 was confirmed through coimmunoprecipitation and colocalization experiments. Mechanism of action studies found that HA15 does not affect viral RNA replication but instead affects late stages of the viral life cycle, which is consistent with GRP78 promoting viral assembly or viral protein trafficking.

scholarly journals The Structural Biology of Eastern Equine Encephalitis Virus, an Emerging Viral Threat

2021 ◽  
Author(s):  
S. Saif Hasan ◽  
Debajit Dey ◽  
Suruchi Singh ◽  
Matthew Martin
Keyword(s):  
Structural Biology ◽  
The United States ◽  
Encephalitis Virus ◽  
Eastern Equine Encephalitis Virus ◽  
Host Proteins ◽  
Structural Investigations ◽  
Eastern Equine Encephalitis ◽  
Equine Encephalitis Virus ◽  
Fundamental Biology ◽  
Functional Analyses

Alphaviruses are arboviruses that cause arthritis and encephalitis in humans. Eastern Equine Encephalitis Virus (EEEV) is a mosquito transmitted alphavirus that is implicated in severe encephalitis in humans with high mortality. However, limited insights are available into its fundamental biology of EEEV and residue-level details of its interactions with host proteins. In recent years, outbreaks of EEEV have been reported mainly in the United States, raising concerns about public safety. This review article summarizes recent advances in the structural biology of EEEV based mainly on recent single particle cryogenic electron microscopy (cryoEM) structures. Together with functional analyses of EEEV and related alphaviruses, these structural investigations provide clues to how EEEV interacts with host proteins, which may open avenues for the development of therapeutics.

scholarly journals Phosphorylation Sites in the Hypervariable Domain in Chikungunya Virus nsP3 Are Crucial for Viral Replication

2021 ◽  
Vol 95 (9) ◽  
Author(s):  
Mona Teppor ◽  
Eva Žusinaite ◽  
Andres Merits
Keyword(s):  
Protein Interactions ◽  
Mammalian Cells ◽  
Sindbis Virus ◽  
Chikungunya Virus ◽  
Semliki Forest Virus ◽  
Virus Infectivity ◽  
Valuable Insight ◽  
Phosphorylation Sites ◽  
Nonstructural Proteins ◽  
Host Proteins

ABSTRACT Chikungunya virus (CHIKV, family Togaviridae) is a mosquito-transmitted alphavirus. The positive-sense RNA genome of CHIKV encodes four nonstructural proteins (nsP1 to nsP4) that are virus-specific subunits of the RNA replicase. Among nsP functions, those of nsP3 are the least understood. The C-terminal hypervariable domain (HVD) in nsP3 is disordered and serves as a platform for interactions with multiple host proteins. For Sindbis virus (SINV) and Semliki Forest virus (SFV), the nsP3 HVD has been shown to be phosphorylated. Deletion of phosphorylated regions has a mild effect on the growth of SFV and SINV in vertebrate cells. Using radiolabeling, we demonstrated that nsP3 in CHIKV and o’nyong-nyong virus is also phosphorylated. We showed that the phosphorylated residues in CHIKV nsP3 are not clustered at the beginning of the HVD. The substitution of 20 Ser/Thr residues located in the N-terminal half of the HVD or 26 Ser/Thr residues located in its C-terminal half with Ala residues reduced the activity of the CHIKV replicase and the infectivity of CHIKV in mammalian cells. Furthermore, the substitution of all 46 potentially phosphorylated residues resulted in the complete loss of viral RNA synthesis and infectivity. The mutations did not affect the interaction of the HVD in nsP3 with the host G3BP1 protein; interactions with CD2AP, BIN1, and FHL1 proteins were significantly reduced but not abolished. Thus, CHIKV differs from SFV and SINV both in the location of the phosphorylated residues in the HVD in nsP3 and, significantly, in their effect on replicase activity and virus infectivity. IMPORTANCE CHIKV outbreaks have affected millions of people, creating a need for the development of antiviral approaches. nsP3 is a component of the CHIKV RNA replicase and is involved in interactions with host proteins and signaling cascades. Phosphorylation of the HVD in nsP3 is important for the virulent alphavirus phenotype. Here, we demonstrate that nsP3 in CHIKV is phosphorylated and that the phosphorylation sites in the HVD are distributed in a unique pattern. Furthermore, the abrogation of some of the phosphorylation sites results in the attenuation of CHIKV, while abolishing all the phosphorylation sites completely blocked its replicase activity. Thus, the phosphorylation of nsP3 and/or the phosphorylation sites in nsP3 have a major impact on CHIKV infectivity. Therefore, they represent promising targets for antiviral compounds and CHIKV attenuation. In addition, this new information offers valuable insight into the vast network of virus-host interactions.

scholarly journals Impact Analysis of SARS-CoV2 on Signaling Pathways during COVID19 Pathogenesis using Codon Usage Assisted Host-Viral Protein Interactions

2020 ◽  
Author(s):  
Jayanta Kumar Das ◽  
Subhadip Chakraborty ◽  
Swarup Roy
Keyword(s):  
Codon Usage ◽  
Signaling Pathways ◽  
Protein Interaction ◽  
Protein Interactions ◽  
Viral Protein ◽  
Viral Proteins ◽  
Host Protein ◽  
Host Proteins ◽  
Disease Pathogenesis ◽  
Pattern Similarity

AbstractUnderstanding the molecular mechanism of COVID19 disease pathogenesis helps in the rapid development of therapeutic targets. Usually, viral protein targets host proteins in an organized fashion. The pathogen may target cell signaling pathways to disrupt the pathway genes’ regular activities, resulting in disease. Understanding the interaction mechanism of viral and host proteins involved in different signaling pathways may help decipher the attacking mechanism on the signal transmission during diseases, followed by discovering appropriate therapeutic solutions.The expression of any viral gene depends mostly on the host translational machinery. Recent studies report the great significance of codon usage biases in establishing host-viral protein-protein interactions (PPI). Exploiting the codon usage patterns between a pair of co-evolved host and viral proteins may present novel insight into the host-viral protein interactomes during disease pathogenesis. Leveraging the codon usage pattern similarity (and dissimilarity), we propose a computational scheme to recreate the hostviral protein interaction network (HVPPI). We use seventeen (17) essential signaling pathways for our current work and study the possible targeting mechanism of SARS-CoV2 viral proteins on such pathway proteins. We infer both negatively and positively interacting edges in the network. We can find a relationship where one host protein may target by more than one viral protein.Extensive analysis performed to understand the network topologically and the attacking behavior of the viral proteins. Our study reveals that viral proteins, mostly utilize codons, rare in the targeted host proteins (negatively correlated interaction). Among non-structural proteins, NSP3 and structural protein, Spike (S) protein, are the most influential proteins in interacting multiple host proteins. In ranking the most affected pathways, MAPK pathways observe to be worst affected during the COVID-19 disease. A good number of targeted proteins are highly central in host protein interaction networks. Proteins participating in multiple pathways are also highly connected in their own PPI and mostly targeted by multiple viral proteins.

scholarly journals The Structural Biology of Eastern Equine Encephalitis Virus, an Emerging Viral Threat

Pathogens ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 973
Author(s):  
S. Saif Hasan ◽  
Debajit Dey ◽  
Suruchi Singh ◽  
Matthew Martin
Keyword(s):  
Structural Biology ◽  
The United States ◽  
Encephalitis Virus ◽  
Eastern Equine Encephalitis Virus ◽  
Host Proteins ◽  
Structural Investigations ◽  
Eastern Equine Encephalitis ◽  
Equine Encephalitis Virus ◽  
Fundamental Biology ◽  
Functional Analyses

Alphaviruses are arboviruses that cause arthritis and encephalitis in humans. Eastern Equine Encephalitis Virus (EEEV) is a mosquito-transmitted alphavirus that is implicated in severe encephalitis in humans with high mortality. However, limited insights are available into the fundamental biology of EEEV and residue-level details of its interactions with host proteins. In recent years, outbreaks of EEEV have been reported mainly in the United States, raising concerns about public safety. This review article summarizes recent advances in the structural biology of EEEV based mainly on single-particle cryogenic electron microscopy (cryoEM) structures. Together with functional analyses of EEEV and related alphaviruses, these structural investigations provide clues to how EEEV interacts with host proteins, which may open avenues for the development of therapeutics.

scholarly journals Proteome-wide cross-linking mass spectrometry to identify specific virus capsid-host interactions between tick-borne encephalitis virus and neuroblastoma cells

2021 ◽  
Author(s):  
Sarah V Barrass ◽  
Lauri I A Pulkkinen ◽  
Olli Vapalahti ◽  
Suvi Kuivanen ◽  
Maria Anastasina ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Protein Interactions ◽  
Neuroblastoma Cells ◽  
Encephalitis Virus ◽  
Host Protein ◽  
Cross Linking ◽  
Host Proteins ◽  
Host Interactions ◽  
Tick Borne Encephalitis ◽  
Tick Borne Encephalitis Virus

Virus-host protein-protein interactions are central to viral infection, but are challenging to identify and characterise, especially in complex systems involving intact viruses and cells. In this work, we demonstrate a proteome-wide approach to identify virus-host interactions using chemical cross-linking coupled with mass spectrometry. We adsorbed tick-borne encephalitis virus onto metabolically-stalled neuroblastoma cells, covalently cross-linked interacting virus-host proteins, and performed limited proteolysis to release primarily the surface-exposed proteins for identification by mass spectrometry. Using the intraviral protein cross-links as an internal control to assess cross-link confidence levels, we identified 22 high confidence unique intraviral cross-links and 59 high confidence unique virus-host protein-protein interactions. The identified host proteins were shown to interact with eight distinct sites on the outer surface of the virus. Notably, we identified an interaction between the substrate-binding domain of heat shock protein family A member 5, an entry receptor for four related flaviviruses, and the hinge region of the viral envelope protein. We also identified host proteins involved in endocytosis, cytoskeletal rearrangement, or located in the cytoskeleton, suggesting that entry mechanisms for tick-borne encephalitis virus could include both clathrin-mediated endocytosis and macropinocytosis. Additionally, cross-linking of the viral proteins showed that the capsid protein forms dimers within tick-borne encephalitis virus, as previously observed with purified C proteins for other flaviviruses. This method enables the identification and mapping of transient virus-host interactions, under near-physiological conditions, without the need for genetic manipulation.

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