Evidence for ubiquitin-regulated nuclear and subnuclear trafficking among Paramyxovirinae matrix proteins.
| Autor: | Mickey Pentecost, Ajay A Vashisht, Talia Lester, Tim Voros, Shannon M Beaty, Arnold Park, Yao E Wang, Tatyana E Yun, Alexander N Freiberg, James A Wohlschlegel, Benhur Lee |
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| Jazyk: | angličtina |
| Rok vydání: | 2015 |
| Předmět: | |
| Zdroj: | PLoS Pathogens, Vol 11, Iss 3, p e1004739 (2015) |
| Druh dokumentu: | article |
| ISSN: | 1553-7366 1553-7374 |
| DOI: | 10.1371/journal.ppat.1004739 |
| Popis: | The paramyxovirus matrix (M) protein is a molecular scaffold required for viral morphogenesis and budding at the plasma membrane. Transient nuclear residence of some M proteins hints at non-structural roles. However, little is known regarding the mechanisms that regulate the nuclear sojourn. Previously, we found that the nuclear-cytoplasmic trafficking of Nipah virus M (NiV-M) is a prerequisite for budding, and is regulated by a bipartite nuclear localization signal (NLSbp), a leucine-rich nuclear export signal (NES), and monoubiquitination of the K258 residue within the NLSbp itself (NLSbp-lysine). To define whether the sequence determinants of nuclear trafficking identified in NiV-M are common among other Paramyxovirinae M proteins, we generated the homologous NES and NLSbp-lysine mutations in M proteins from the five major Paramyxovirinae genera. Using quantitative 3D confocal microscopy, we determined that the NES and NLSbp-lysine are required for the efficient nuclear export of the M proteins of Nipah virus, Hendra virus, Sendai virus, and Mumps virus. Pharmacological depletion of free ubiquitin or mutation of the conserved NLSbp-lysine to an arginine, which inhibits M ubiquitination, also results in nuclear and nucleolar retention of these M proteins. Recombinant Sendai virus (rSeV-eGFP) bearing the NES or NLSbp-lysine M mutants rescued at similar efficiencies to wild type. However, foci of cells expressing the M mutants displayed marked fusogenicity in contrast to wild type, and infection did not spread. Recombinant Mumps virus (rMuV-eGFP) bearing the homologous mutations showed similar defects in viral morphogenesis. Finally, shotgun proteomics experiments indicated that the interactomes of Paramyxovirinae M proteins are significantly enriched for components of the nuclear pore complex, nuclear transport receptors, and nucleolar proteins. We then synthesize our functional and proteomics data to propose a working model for the ubiquitin-regulated nuclear-cytoplasmic trafficking of cognate paramyxovirus M proteins that show a consistent nuclear trafficking phenotype. |
| Databáze: | Directory of Open Access Journals |
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