A Hyperstabilizing Mutation in the Base of the Ebola Virus Glycoprotein Acts at Multiple Steps To Abrogate Viral Entry

ABSTRACT Ebola virus (EBOV) causes highly lethal disease outbreaks against which no FDA-approved countermeasures are available. Although many host factors exploited by EBOV for cell entry have been identified, including host cell surface phosphatidylserine receptors, endosomal cysteine proteases, an...

Descripción completa

Guardado en:

Detalles Bibliográficos
Autores principales:	J. Maximilian Fels, Jennifer S. Spence, Robert H. Bortz, Zachary A. Bornholdt, Kartik Chandran
Formato:	article
Lenguaje:	EN
Publicado:	American Society for Microbiology 2019
Materias:	Ebola cell entry ebolavirus filovirus fusion activation glycoprotein Microbiology QR1-502
Acceso en línea:	https://doaj.org/article/20567a5fc6a94a1da98fb64f9492e78d
Etiquetas:	Agregar Etiqueta Sin Etiquetas, Sea el primero en etiquetar este registro!

id	oai:doaj.org-article:20567a5fc6a94a1da98fb64f9492e78d
record_format	dspace
spelling	oai:doaj.org-article:20567a5fc6a94a1da98fb64f9492e78d2021-11-15T16:22:08ZA Hyperstabilizing Mutation in the Base of the Ebola Virus Glycoprotein Acts at Multiple Steps To Abrogate Viral Entry10.1128/mBio.01408-192150-7511https://doaj.org/article/20567a5fc6a94a1da98fb64f9492e78d2019-08-01T00:00:00Zhttps://journals.asm.org/doi/10.1128/mBio.01408-19https://doaj.org/toc/2150-7511ABSTRACT Ebola virus (EBOV) causes highly lethal disease outbreaks against which no FDA-approved countermeasures are available. Although many host factors exploited by EBOV for cell entry have been identified, including host cell surface phosphatidylserine receptors, endosomal cysteine proteases, and the lysosomal cholesterol trafficking protein NPC1, key questions remain. Specifically, late entry steps culminating in viral membrane fusion remain enigmatic. Here, we investigated a set of glycoprotein (GP) mutants previously hypothesized to be entry defective and identified one mutation, R64A, that abolished infection with no apparent impact on GP expression, folding, or viral incorporation. R64A profoundly thermostabilized EBOV GP and rendered it highly resistant to proteolysis in vitro. Forward-genetics and cell entry studies strongly suggested that R64A’s effects on GP thermostability and proteolysis arrest viral entry at least at two distinct steps: the first upstream of NPC1 binding and the second at a late entry step downstream of fusion activation. Concordantly, toremifene, a small-molecule entry inhibitor previously shown to bind and destabilize GP, may selectively enhance the infectivity of viral particles bearing GP(R64A) at subinhibitory concentrations. R64A provides a valuable tool to further define the interplay between GP stability, proteolysis, and viral membrane fusion; to explore the rational design of stability-modulating antivirals; and to spur the development of next-generation Ebola virus vaccines with improved stability. IMPORTANCE Ebola virus is a medically relevant virus responsible for outbreaks of severe disease in western and central Africa, with mortality rates reaching as high as 90%. Despite considerable effort, there are currently no FDA-approved therapeutics or targeted interventions available, highlighting the need of development in this area. Host-cell invasion represents an attractive target for antivirals, and several drug candidates have been identified; however, our limited understanding of the complex viral entry process challenges the development of such entry-targeting drugs. Here, we report on a glycoprotein mutation that abrogates viral entry and provides insights into the final steps of this process. In addition, the hyperstabilized phenotype of this mutant makes it useful as a tool in the discovery and design of stability-modulating antivirals and next-generation vaccines against Ebola virus.J. Maximilian FelsJennifer S. SpenceRobert H. BortzZachary A. BornholdtKartik ChandranAmerican Society for MicrobiologyarticleEbolacell entryebolavirusfilovirusfusion activationglycoproteinMicrobiologyQR1-502ENmBio, Vol 10, Iss 4 (2019)
institution	DOAJ
collection	DOAJ
language	EN
topic	Ebola cell entry ebolavirus filovirus fusion activation glycoprotein Microbiology QR1-502
spellingShingle	Ebola cell entry ebolavirus filovirus fusion activation glycoprotein Microbiology QR1-502 J. Maximilian Fels Jennifer S. Spence Robert H. Bortz Zachary A. Bornholdt Kartik Chandran A Hyperstabilizing Mutation in the Base of the Ebola Virus Glycoprotein Acts at Multiple Steps To Abrogate Viral Entry
description	ABSTRACT Ebola virus (EBOV) causes highly lethal disease outbreaks against which no FDA-approved countermeasures are available. Although many host factors exploited by EBOV for cell entry have been identified, including host cell surface phosphatidylserine receptors, endosomal cysteine proteases, and the lysosomal cholesterol trafficking protein NPC1, key questions remain. Specifically, late entry steps culminating in viral membrane fusion remain enigmatic. Here, we investigated a set of glycoprotein (GP) mutants previously hypothesized to be entry defective and identified one mutation, R64A, that abolished infection with no apparent impact on GP expression, folding, or viral incorporation. R64A profoundly thermostabilized EBOV GP and rendered it highly resistant to proteolysis in vitro. Forward-genetics and cell entry studies strongly suggested that R64A’s effects on GP thermostability and proteolysis arrest viral entry at least at two distinct steps: the first upstream of NPC1 binding and the second at a late entry step downstream of fusion activation. Concordantly, toremifene, a small-molecule entry inhibitor previously shown to bind and destabilize GP, may selectively enhance the infectivity of viral particles bearing GP(R64A) at subinhibitory concentrations. R64A provides a valuable tool to further define the interplay between GP stability, proteolysis, and viral membrane fusion; to explore the rational design of stability-modulating antivirals; and to spur the development of next-generation Ebola virus vaccines with improved stability. IMPORTANCE Ebola virus is a medically relevant virus responsible for outbreaks of severe disease in western and central Africa, with mortality rates reaching as high as 90%. Despite considerable effort, there are currently no FDA-approved therapeutics or targeted interventions available, highlighting the need of development in this area. Host-cell invasion represents an attractive target for antivirals, and several drug candidates have been identified; however, our limited understanding of the complex viral entry process challenges the development of such entry-targeting drugs. Here, we report on a glycoprotein mutation that abrogates viral entry and provides insights into the final steps of this process. In addition, the hyperstabilized phenotype of this mutant makes it useful as a tool in the discovery and design of stability-modulating antivirals and next-generation vaccines against Ebola virus.
format	article
author	J. Maximilian Fels Jennifer S. Spence Robert H. Bortz Zachary A. Bornholdt Kartik Chandran
author_facet	J. Maximilian Fels Jennifer S. Spence Robert H. Bortz Zachary A. Bornholdt Kartik Chandran
author_sort	J. Maximilian Fels
title	A Hyperstabilizing Mutation in the Base of the Ebola Virus Glycoprotein Acts at Multiple Steps To Abrogate Viral Entry
title_short	A Hyperstabilizing Mutation in the Base of the Ebola Virus Glycoprotein Acts at Multiple Steps To Abrogate Viral Entry
title_full	A Hyperstabilizing Mutation in the Base of the Ebola Virus Glycoprotein Acts at Multiple Steps To Abrogate Viral Entry
title_fullStr	A Hyperstabilizing Mutation in the Base of the Ebola Virus Glycoprotein Acts at Multiple Steps To Abrogate Viral Entry
title_full_unstemmed	A Hyperstabilizing Mutation in the Base of the Ebola Virus Glycoprotein Acts at Multiple Steps To Abrogate Viral Entry
title_sort	hyperstabilizing mutation in the base of the ebola virus glycoprotein acts at multiple steps to abrogate viral entry
publisher	American Society for Microbiology
publishDate	2019
url	https://doaj.org/article/20567a5fc6a94a1da98fb64f9492e78d
work_keys_str_mv	AT jmaximilianfels ahyperstabilizingmutationinthebaseoftheebolavirusglycoproteinactsatmultiplestepstoabrogateviralentry AT jennifersspence ahyperstabilizingmutationinthebaseoftheebolavirusglycoproteinactsatmultiplestepstoabrogateviralentry AT roberthbortz ahyperstabilizingmutationinthebaseoftheebolavirusglycoproteinactsatmultiplestepstoabrogateviralentry AT zacharyabornholdt ahyperstabilizingmutationinthebaseoftheebolavirusglycoproteinactsatmultiplestepstoabrogateviralentry AT kartikchandran ahyperstabilizingmutationinthebaseoftheebolavirusglycoproteinactsatmultiplestepstoabrogateviralentry AT jmaximilianfels hyperstabilizingmutationinthebaseoftheebolavirusglycoproteinactsatmultiplestepstoabrogateviralentry AT jennifersspence hyperstabilizingmutationinthebaseoftheebolavirusglycoproteinactsatmultiplestepstoabrogateviralentry AT roberthbortz hyperstabilizingmutationinthebaseoftheebolavirusglycoproteinactsatmultiplestepstoabrogateviralentry AT zacharyabornholdt hyperstabilizingmutationinthebaseoftheebolavirusglycoproteinactsatmultiplestepstoabrogateviralentry AT kartikchandran hyperstabilizingmutationinthebaseoftheebolavirusglycoproteinactsatmultiplestepstoabrogateviralentry
_version_	1718426891626479616

A Hyperstabilizing Mutation in the Base of the Ebola Virus Glycoprotein Acts at Multiple Steps To Abrogate Viral Entry

Ejemplares similares