Production of a dominant-negative fragment due to G3BP1 cleavage contributes to the disruption of mitochondria-associated protective stress granules during CVB3 infection.

TitleProduction of a dominant-negative fragment due to G3BP1 cleavage contributes to the disruption of mitochondria-associated protective stress granules during CVB3 infection.
Publication TypeJournal Article
Year of Publication2013
AuthorsFung, G, Ng, CSeng, Zhang, J, Shi, J, Wong, J, Piesik, P, Han, L, Chu, F, Jagdeo, J, Jan, E, Fujita, T, Luo, H
JournalPLoS One
Volume8
Issue11
Paginatione79546
Date Published2013
ISSN1932-6203
KeywordsBlotting, Western, Carrier Proteins, Coxsackievirus Infections, Cytoplasmic Granules, Fluorescent Antibody Technique, Indirect, HeLa Cells, Humans, In Situ Hybridization, Microscopy, Electron, Transmission, Microscopy, Immunoelectron, Mitochondria, Reverse Transcriptase Polymerase Chain Reaction, Virus Replication
Abstract

Stress granules (SGs) are dynamic cytosolic aggregates containing messenger ribonucleoproteins and target poly-adenylated (A)-mRNA. A key component of SGs is Ras-GAP SH3 domain binding protein-1 (G3BP1), which in part mediates protein-protein and protein-RNA interactions. SGs are modulated during infection by several viruses, however, the function and significance of this process remains poorly understood. In this study, we investigated the interplay between SGs and Coxsackievirus type B3 (CVB3), a member of the Picornaviridae family. Our studies demonstrated that SGs were formed early during CVB3 infection; however, G3BP1-positive SGs were actively disassembled at 5 hrs post-infection, while poly(A)-positive RNA granules persisted. Furthermore, we confirmed G3BP1 cleavage by 3C(pro) at Q325. We also demonstrated that overexpression of G3BP1-SGs negatively impacted viral replication at the RNA, protein, and viral progeny levels. Using electron microscopy techniques, we showed that G3BP1-positive SGs localized near mitochondrial surfaces. Finally, we provided evidence that the C-terminal cleavage product of G3BP1 inhibited SG formation and promoted CVB3 replication. Taken together, we conclude that CVB3 infection selectively targets G3BP1-SGs by cleaving G3BP1 to produce a dominant-negative fragment that further inhibits G3BP1-SG formation and facilitates viral replication.

DOI10.1371/journal.pone.0079546
Alternate JournalPLoS ONE
PubMed ID24260247
PubMed Central IDPMC3832613
Grant List / / Canadian Institutes of Health Research / Canada