title: Production of a dominant-negative fragment due to G3BP1 cleavage contributes to the disruption of mitochondria-associated protective stress granules during CVB3 infection.
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.
authors.affiliation: Department of Pathology and Laboratory Medicine, University of British Columbia, James Hogg Research Center, Providence Heart+Lung Institute, St. Paul's Hospital Vancouver, Vancouver, British Columbia, Canada.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Fung
authors.forename: Chen Seng
authors.initials: CS
authors.lastname: Ng
authors.forename: Jingchun
authors.initials: J
authors.lastname: Zhang
authors.forename: Junyan
authors.initials: J
authors.lastname: Shi
authors.forename: Jerry
authors.initials: J
authors.lastname: Wong
authors.forename: Paulina
authors.initials: P
authors.lastname: Piesik
authors.forename: Lillian
authors.initials: L
authors.lastname: Han
authors.forename: Fanny
authors.initials: F
authors.lastname: Chu
authors.forename: Julienne
authors.initials: J
authors.lastname: Jagdeo
authors.forename: Eric
authors.initials: E
authors.lastname: Jan
authors.forename: Takashi
authors.initials: T
authors.lastname: Fujita
authors.forename: Honglin
authors.initials: H
authors.lastname: Luo
mesh_terms: D015153:Blotting, Western; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D003384:Coxsackievirus Infections / Q000378:metabolism*; D003594:Cytoplasmic Granules / Q000378:metabolism* / Q000648:ultrastructure; D004265:DNA Helicases; D019084:Fluorescent Antibody Technique, Indirect; D006367:HeLa Cells; D006801:Humans; D017403:In Situ Hybridization; D046529:Microscopy, Electron, Transmission; D016253:Microscopy, Immunoelectron; D008928:Mitochondria / Q000378:metabolism* / Q000648:ultrastructure; D000075223:Poly-ADP-Ribose Binding Proteins; D020365:RNA Helicases; D000067776:RNA Recognition Motif Proteins; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014779:Virus Replication / Q000502:physiology
chemical_list: D002352:Carrier Proteins; D000075223:Poly-ADP-Ribose Binding Proteins; D000067776:RNA Recognition Motif Proteins; D004265:DNA Helicases; C116070:G3BP1 protein, human; D020365:RNA Helicases