The Infectious Bronchitis Coronavirus Envelope Protein Alters Golgi pH To Protect the Spike Protein and Promote the Release of Infectious Virus

Copyright © 2019 American Society for Microbiology..

Coronaviruses (CoVs) assemble by budding into the lumen of the early Golgi complex prior to exocytosis. The small CoV envelope (E) protein plays roles in assembly, virion release, and pathogenesis. CoV E has a single hydrophobic domain (HD), is targeted to Golgi membranes, and has cation channel activity in vitro The E protein from avian infectious bronchitis virus (IBV) has dramatic effects on the secretory system, which require residues in the HD. Mutation of the HD of IBV E in a recombinant virus background results in impaired growth kinetics, impaired release of infectious virions, accumulation of IBV spike (S) protein on the plasma membrane compared to wild-type (WT) IBV-infected cells, and aberrant cleavage of IBV S on virions. We previously reported the formation of two distinct oligomeric pools of IBV E in transfected and infected cells. Disruption of the secretory pathway by IBV E correlates with a form that is likely monomeric, suggesting that the effects on the secretory pathway are independent of E ion channel activity. Here, we present evidence suggesting that the monomeric form of IBV E correlates with an increased Golgi luminal pH. Infection with IBV or expression of IBV E induces neutralization of Golgi pH, promoting a model in which IBV E alters the secretory pathway through interaction with host cell factors, protecting IBV S from premature cleavage and leading to the efficient release of infectious virus from the cells. This is the first demonstration of a coronavirus-induced alteration in the microenvironment of the secretory pathway.IMPORTANCE Coronaviruses are important human pathogens with significant zoonotic potential. Progress has been made toward identifying potential vaccine candidates for highly pathogenic human CoVs, including the use of attenuated viruses that lack the CoV E protein or express E mutants. However, no approved vaccines or antiviral therapeutics exist. Understanding the role of the CoV E protein in virus assembly and release is thus an important prerequisite for potential vaccines as well as in identifying novel antiviral therapeutics.

Medienart:

E-Artikel

Erscheinungsjahr:

2019

Erschienen:

2019

Enthalten in:

Zur Gesamtaufnahme - volume:93

Enthalten in:

Journal of virology - 93(2019), 11 vom: 01. Juni

Sprache:

Englisch

Beteiligte Personen:

Westerbeck, Jason W [VerfasserIn]
Machamer, Carolyn E [VerfasserIn]

Links:

Volltext

Themen:

Coronavirus
Coronavirus Envelope Proteins
E protein
Envelope protein, SARS-CoV-2
Golgi
Journal Article
Oligomers
PH
Research Support, N.I.H., Extramural
Spike Glycoprotein, Coronavirus
Viral Envelope Proteins
Viroporin

Anmerkungen:

Date Completed 23.06.2020

Date Revised 07.11.2023

published: Electronic-Print

Citation Status MEDLINE

doi:

10.1128/JVI.00015-19

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM294904654