Browsing by Author "Narayanan, Aarthi"
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- Proteomic Discovery of VEEV E2-Host Partner Interactions Identifies GRP78 Inhibitor HA15 as a Potential Therapeutic for Alphavirus InfectionsBarrera, Michael D.; Callahan, Victoria; Akhrymuk, Ivan V.; Bhalla, Nishank; Zhou, Weidong; Campbell, Catherine; Narayanan, Aarthi; Kehn-Hall, Kylene (MDPI, 2021-03-02)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.
- Rift Valley fever virus Gn V5-epitope tagged virus enables identification of UBR4 as a Gn interacting protein that facilitates Rift Valley fever virus productionBracci, Nicole; de la Fuente, Cynthia; Saleem, Sahar; Pinkham, Chelsea; Narayanan, Aarthi; Garcia-Sastre, Adolfo; Balaraman, Velmurugan; Richt, Juergen A.; Wilson, William; Kehn-Hall, Kylene (Academic Press, 2022-02)Rift Valley fever virus (RVFV) is an arbovirus that was first reported in the Rift Valley of Kenya which causes significant disease in humans and livestock. RVFV is a tri-segmented, negative-sense RNA virus consisting of a L, M, and S segments with the M segment encoding the glycoproteins Gn and Gc. Host factors that interact with Gn are largely unknown. To this end, two viruses containing an epitope tag (V5) on the Gn protein in position 105 or 229 (V5Gn105 and V5Gn229) were generated using the RVFV MP-12 vaccine strain as a backbone. The V5-tag insertion minimally impacted Gn functionality as measured by replication kinetics, Gn localization, and antibody neutralization assays. A proteomics-based approach was used to identify novel Gn-binding host proteins, including the E3 ubiquitin-protein ligase, UBR4. Depletion of UBR4 resulted in a significant decrease in RVFV titers and a reduction in viral RNA production.