Cited by 99Nuclear Structure and FunctionViral Infections and Immunology ResearchVirology and Viral Diseases

Leader-Induced Phosphorylation of Nucleoporins Correlates with Nuclear Trafficking Inhibition by Cardioviruses

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Porter, Frederick W., Palmenberg, Ann C.·2009·Journal of Virology

Abstract

Picornaviruses disrupt nucleocytoplasmic trafficking pathways during infection. Poliovirus and rhinovirus inhibit nuclear protein import/export through a series of 2A protease-dependent cleavages within nuclear pore proteins (nucleoporins [Nups]), including Nup62, Nup98, and Nup153. Cardioviruses lack the same protease and instead affect trafficking inhibition through an activity mapped to their leader (L) protein, a 67- to 76-amino acid (aa) polypeptide with no known enzymatic activity. We have shown that L from encephalomyocarditis virus (EMCV) binds and inhibits the activity of Ran-GTPase, a key regulator of nucleocytoplasmic transport. We now report that recombinant EMCV L triggers the unregulated efflux of protein cargo from preloaded HeLa cell nuclei in cell-free reactions dependent upon Xenopus egg cytosol or HeLa cell-derived cytosol. Recombinant L was the only viral protein necessary for this activity or for nuclear protein import inhibition. Mutational disruption of the L protein zinc finger domain (C 19 A) abrogated the inhibitory activity for both import and efflux in cell extracts, but mutations in the C-terminal acidic domain of L (aa 37 to 61) did not. Notably, HeLa cell nuclei treated with L, or those from EMCV-infected cells, showed reproducibly altered patterns of nucleoporin phosphorylation. Nup62, Nup153, and Nup214 each became hyperphosphorylated in an L-dependent manner. Staurosporine, a broad-spectrum kinase inhibitor, blocked this phosphorylation and rescued nuclear import/export activity from L-dependent inhibition. Therefore, cardioviruses target the same group of nucleoporins as enteroviruses, but the effector mechanism triggered by L (or L-Ran complexes) involves a unique cytosol-dependent phosphorylation cascade rather than proteolysis.

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  • EMCV L protein appears to suppress interferon production and impair nucleo-cytoplasmic trafficking through the binding of Ran-GTPase and through phosphorylation and inactivation of nucleoporins.

    “Even if EMCV L protein is devoid of any known enzymatic activity, in contrast to that of aphtovirus, it appears to suppress interferon production149 and impair nucleo-cytoplasmic trafficking through the binding of Ran-GTPase (Ras-related nuclear -GTPase required for the RNA and protein translocation through the nuclear pores) and through phosphorylation and inactivation of nucleoporins.150-154”

    From The encephalomyocarditis virus (2012) · cites this paper as [153]

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Authors
Porter, F. W., & Palmenberg, A. C.
Affiliations
University of Wisconsin–Madison (US)
Venue
Journal of Virology
Published
2009-02-15
Volume
83
Issue
4
Pages
1941-1951
ISSN
  • 0022-538X (ISSN-L)
  • 1098-5514
OpenAlex
W2134535288
Cited by
96
References
38
Citations by year
2026: 1 · 2025: 4 · 2024: 5 · 2023: 1 · 2022: 5 · 2021: 5 · 2020: 3 · 2019: 7 · 2018: 4 · 2017: 2 · 2016: 4 · 2015: 8 · 2014: 11 · 2013: 9 · 2012: 9
FWCI
2.61
Type
journal article
Language
en
Open access
Locations
  • Journal of Virology (publishedVersion)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
Funders
  • National Institutes of Health (AI017331)
  • National Institute of Allergy and Infectious Diseases (R56AI017331, R01AI017331, AI017331)
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Nuclear Structure and Function
  • Health Sciences › Medicine › Cardiology and Cardiovascular Medicine › Viral Infections and Immunology Research
  • Health Sciences › Medicine › Epidemiology › Virology and Viral Diseases
Keywords
encephalomyocarditis virus, Ran GTPase, Nup62, Nup153, Nup214, nuclear import inhibition, nuclear export, zinc finger, staurosporine, picornavirus
MeSH terms
Animals, Cell Nucleus, Cytoplasm, Encephalomyocarditis virus, HeLa Cells, Humans, Mutation, Ovum, Phosphorylation, Viral Proteins, Xenopus, Protein Transport, Nuclear Pore Complex Proteins

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