An Interaction between Glutathione and the Capsid Is Required for the Morphogenesis of C-Cluster Enteroviruses

PLoS Pathogens

Nihal Altan-Bonnet¹  Ying-Han Chen¹  Ying Liu²  Hsin-Chieh Ma²  Aniko V. Paul²  Ping Jiang²  Eckard Wimmer²  Steffen Mueller²  Chunling Wang³  Michael Strauss⁴  James Hogle⁴  Nina Rehage⁵ 

[1] Department of Biological Sciences, Rutgers University, Newark, New Jersey, United States of America;Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, New York, United States of America;Division of Infectious Diseases and Vaccinology, School of Public Health, University of California, Berkeley, Berkeley, California, United States of America;Harvard Medical School, Boston, Massachusetts, United States of America;Helmholtz Centrum München, Munich, Germany

关键词: Viral packaging;    HeLa cells;    Morphogenesis;    Poliovirus;    Virions;    Enterovirus infection;    Viral replication;    Encapsidation;   

DOI  :  10.1371/journal.ppat.1004052

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

Glutathione (GSH) is the most abundant cellular thiol playing an essential role in preserving a reduced cellular environment. Cellular GSH levels can be efficiently reduced by the GSH biosynthesis inhibitor, L-buthionine sulfoximine (BSO). The aim of our study was to determine the role of GSH in the growth of two C-cluster enteroviruses, poliovirus type 1 (PV1) and coxsackievirus A20 (CAV20). Our results show that the growth of both PV1 and CAV20 is strongly inhibited by BSO and can be partially reversed by the addition of GSH. BSO has no effect on viral protein synthesis or RNA replication but it strikingly reduces the accumulation of 14S pentamers in infected cells. GSH-pull down assays show that GSH directly interacts with capsid precursors and mature virus made in the absence of BSO whereas capsid precursors produced under GSH-depletion do not bind to GSH. In particular, the loss of binding of GSH may debilitate the stability of 14S pentamers, resulting in their failure to assemble into mature virus. Immunofluorescence cell imaging demonstrated that GSH-depletion did not affect the localization of viral capsid proteins to the replication complex. PV1 BSO resistant (BSOr) mutants evolved readily during passaging of the virus in the presence of BSO. Structural analyses revealed that the BSOr mutations, mapping to VP1 and VP3 capsid proteins, are primarily located at protomer/protomer interfaces. BSOr mutations might, in place of GSH, aid the stability of 14S particles that is required for virion maturation. Our observation that BSOr mutants are more heat resistant and need less GSH than wt virus to be protected from heat inactivation suggests that they possess a more stable capsid. We propose that the role of GSH during enterovirus morphogenesis is to stabilize capsid structures by direct interaction with capsid proteins both during and after the formation of mature virus particles.

【 授权许可】

CC BY