title: Cytoplasmic translocation, aggregation, and cleavage of TDP-43 by enteroviral proteases modulate viral pathogenesis.
abstract: We have previously demonstrated that infection by coxsackievirus B3 (CVB3), a positive-stranded RNA enterovirus, results in the accumulation of insoluble ubiquitin-protein aggregates, which resembles the common feature of neurodegenerative diseases. The importance of protein aggregation in viral pathogenesis has been recognized; however, the underlying regulatory mechanisms remain ill-defined. Transactive response DNA-binding protein-43 (TDP-43) is an RNA-binding protein that has an essential role in regulating RNA metabolism at multiple levels. Cleavage and cytoplasmic aggregation of TDP-43 serves as a major molecular marker for amyotrophic lateral sclerosis and frontotemporal lobar degeneration and contributes significantly to disease progression. In this study, we reported that TDP-43 is translocated from the nucleus to the cytoplasm during CVB3 infection through the activity of viral protease 2A, followed by the cleavage mediated by viral protease 3C. Cytoplasmic translocation of TDP-43 is accompanied by reduced solubility and increased formation of protein aggregates. The cleavage takes place at amino-acid 327 between glutamine and alanine, resulting in the generation of an N- and C-terminal cleavage fragment of ~35 and ~8 kDa, respectively. The C-terminal product of TDP-43 is unstable and quickly degraded through the proteasome degradation pathway, whereas the N-terminal truncation of TDP-43 acts as a dominant-negative mutant that inhibits the function of native TDP-43 in alternative RNA splicing. Lastly, we demonstrated that knockdown of TDP-43 results in an increase in viral titers, suggesting a protective role for TDP-43 in CVB3 infection. Taken together, our findings suggest a novel model by which cytoplasmic redistribution and cleavage of TDP-43 as a consequence of CVB3 infection disrupts the solubility and transcriptional activity of TDP-43. Our results also reveal a mechanism evolved by enteroviruses to support efficient viral infection.
authors.affiliation: Department of Pathology and Laboratory Medicine, Centre for Heart Lung Innovation, St Paul's Hospital, University of British Columbia, Vancouver, BC, Canada.
authors.forename: G
authors.initials: G
authors.lastname: Fung
authors.affiliation: Department of Pathology and Laboratory Medicine, Centre for Heart Lung Innovation, St Paul's Hospital, University of British Columbia, Vancouver, BC, Canada.
authors.forename: J
authors.initials: J
authors.lastname: Shi
authors.affiliation: Department of Pathology and Laboratory Medicine, Centre for Heart Lung Innovation, St Paul's Hospital, University of British Columbia, Vancouver, BC, Canada.
authors.forename: H
authors.initials: H
authors.lastname: Deng
authors.affiliation: Department of Pathology and Laboratory Medicine, Centre for Heart Lung Innovation, St Paul's Hospital, University of British Columbia, Vancouver, BC, Canada.|Department of Pharmacy, Chengdu Military General Hospital, Chengdu, China.
authors.forename: J
authors.initials: J
authors.lastname: Hou
authors.affiliation: Department of Pathology and Laboratory Medicine, Centre for Heart Lung Innovation, St Paul's Hospital, University of British Columbia, Vancouver, BC, Canada.
authors.forename: C
authors.initials: C
authors.lastname: Wang
authors.affiliation: Department of Pathology and Laboratory Medicine, Centre for Heart Lung Innovation, St Paul's Hospital, University of British Columbia, Vancouver, BC, Canada.
authors.forename: A
authors.initials: A
authors.lastname: Hong
authors.affiliation: Department of Pathology and Laboratory Medicine, Centre for Heart Lung Innovation, St Paul's Hospital, University of British Columbia, Vancouver, BC, Canada.
authors.forename: J
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Surgery, Brain Research Centre, University British Columbia, Vancouver, BC, Canada.
authors.forename: W
authors.initials: W
authors.lastname: Jia
authors.affiliation: Department of Pathology and Laboratory Medicine, Centre for Heart Lung Innovation, St Paul's Hospital, University of British Columbia, Vancouver, BC, Canada.
authors.forename: H
authors.initials: H
authors.lastname: Luo
mesh_terms: D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D010450:Endopeptidases / Q000378:metabolism*; D029822:Enterovirus B, Human / Q000201:enzymology* / Q000502:physiology; D006367:HeLa Cells; D006801:Humans; D008297:Male; D051379:Mice; D008856:Microscopy, Fluorescence; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D014779:Virus Replication
chemical_list: D004268:DNA-Binding Proteins; D020033:Protein Isoforms; D034741:RNA, Small Interfering; C000598624:TARDBP protein, human; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D010450:Endopeptidases; D046988:Proteasome Endopeptidase Complex