Binding of glutathione to enterovirus capsids is essential for virion morphogenesis.
Enteroviruses (family of the Picornaviridae) cover a large group of medically important human pathogens for which no antiviral treatment is approved. Although these viruses have been extensively studied, some aspects of the viral life cycle, in particular morphogenesis, are yet poorly understood. We report the discovery of TP219 as a novel inhibitor of the replication of several enteroviruses, including coxsackievirus and poliovirus. We show that TP219 binds directly glutathione (GSH), thereby rapidly depleting intracellular GSH levels and that this interferes with virus morphogenesis without affecting viral RNA replication. The inhibitory effect on assembly was shown not to depend on an altered reducing environment. Using TP219, we show that GSH is an essential stabilizing cofactor during the transition of protomeric particles into pentameric particles. Sequential passaging of coxsackievirus B3 in the presence of low GSH-levels selected for GSH-independent mutants that harbored a surface-exposed methionine in VP1 at the interface between two protomers. In line with this observation, enteroviruses that already contained this surface-exposed methionine, such as EV71, did not rely on GSH for virus morphogenesis. Biochemical and microscopical analysis provided strong evidence for a direct interaction between GSH and wildtype VP1 and a role for this interaction in localizing assembly intermediates to replication sites. Consistently, the interaction between GSH and mutant VP1 was abolished resulting in a relocalization of the assembly intermediates to replication sites independent from GSH. This study thus reveals GSH as a novel stabilizing host factor essential for the production of infectious enterovirus progeny and provides new insights into the poorly understood process of morphogenesis.
Department of Microbiology and Immunology, Rega Institute for Medical Research, University of Leuven, Leuven, Belgium; Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
Hendrik Jan
HJ
Thibaut
Department of Microbiology and Immunology, Rega Institute for Medical Research, University of Leuven, Leuven, Belgium; Department Medical Microbiology, Radboud University Nijmegen Medical Centre, Nijmegen Centre for Molecular Life Sciences, Nijmegen, The Netherlands.
Lonneke
L
van der Linden
Department of Molecular Genetics and Microbiology, School of Medicine, Stony Brook University, Stony Brook, New York, United States of America.
Ping
P
Jiang
Department of Pharmaceutical Biotechnology & Molecular Biology, Vrije Universiteit Brussel, Brussel, Belgium.
Bert
B
Thys
Instituto de Química Médica (IQM-CSIC), Madrid, Spain.
María-Dolores
MD
Canela
Instituto de Química Médica (IQM-CSIC), Madrid, Spain.
Leire
L
Aguado
Department of Pharmaceutical Biotechnology & Molecular Biology, Vrije Universiteit Brussel, Brussel, Belgium.
Bart
B
Rombaut
Department of Molecular Genetics and Microbiology, School of Medicine, Stony Brook University, Stony Brook, New York, United States of America.
Eckard
E
Wimmer
Department of Molecular Genetics and Microbiology, School of Medicine, Stony Brook University, Stony Brook, New York, United States of America.
Aniko
A
Paul
Instituto de Química Médica (IQM-CSIC), Madrid, Spain.
María-Jesús
MJ
Pérez-Pérez
Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands; Department Medical Microbiology, Radboud University Nijmegen Medical Centre, Nijmegen Centre for Molecular Life Sciences, Nijmegen, The Netherlands.
Frank J M
FJ
van Kuppeveld
Department of Microbiology and Immunology, Rega Institute for Medical Research, University of Leuven, Leuven, Belgium.
Johan
J
Neyts
D000818:Animals; D002213:Capsid / Q000378:metabolism*; D002522:Chlorocebus aethiops; D029822:Enterovirus B, Human / Q000502:physiology*; D004769:Enterovirus Infections / Q000235:genetics / Q000378:metabolism*; D005978:Glutathione / Q000235:genetics / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D009154:Mutation; D012367:RNA, Viral / Q000096:biosynthesis* / Q000235:genetics; D014709:Vero Cells; D014779:Virus Replication / Q000502:physiology*
D012367:RNA, Viral; D005978:Glutathione