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Consecutive Inhibition of ISG15 Expression and ISGylation by Cytomegalovirus Regulators
Interferon-stimulated gene 15 (ISG15) encodes an ubiquitin-like protein that covalently conjugates protein. Protein modification by ISG15 (ISGylation) is known to inhibit the replication of many viruses. However, studies on the viral targets and viral strategies to regulate ISGylation-mediated antiv...
Autores principales: | , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Public Library of Science
2016
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5001722/ https://www.ncbi.nlm.nih.gov/pubmed/27564865 http://dx.doi.org/10.1371/journal.ppat.1005850 |
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author | Kim, Ye Ji Kim, Eui Tae Kim, Young-Eui Lee, Myoung Kyu Kwon, Ki Mun Kim, Keun Il Stamminger, Thomas Ahn, Jin-Hyun |
author_facet | Kim, Ye Ji Kim, Eui Tae Kim, Young-Eui Lee, Myoung Kyu Kwon, Ki Mun Kim, Keun Il Stamminger, Thomas Ahn, Jin-Hyun |
author_sort | Kim, Ye Ji |
collection | PubMed |
description | Interferon-stimulated gene 15 (ISG15) encodes an ubiquitin-like protein that covalently conjugates protein. Protein modification by ISG15 (ISGylation) is known to inhibit the replication of many viruses. However, studies on the viral targets and viral strategies to regulate ISGylation-mediated antiviral responses are limited. In this study, we show that human cytomegalovirus (HCMV) replication is inhibited by ISGylation, but the virus has evolved multiple countermeasures. HCMV-induced ISG15 expression was mitigated by IE1, a viral inhibitor of interferon signaling, however, ISGylation was still strongly upregulated during virus infection. RNA interference of UBE1L (E1), UbcH8 (E2), Herc5 (E3), and UBP43 (ISG15 protease) revealed that ISGylation inhibits HCMV growth by downregulating viral gene expression and virion release in a manner that is more prominent at low multiplicity of infection. A viral regulator pUL26 was found to interact with ISG15, UBE1L, and Herc5, and be ISGylated. ISGylation of pUL26 regulated its stability and inhibited its activities to suppress NF-κB signaling and complement the growth of UL26-null mutant virus. Moreover, pUL26 reciprocally suppressed virus-induced ISGylation independent of its own ISGylation. Consistently, ISGylation was more pronounced in infections with the UL26-deleted mutant virus, whose growth was more sensitive to IFNβ treatment than that of the wild-type virus. Therefore, pUL26 is a viral ISG15 target that also counteracts ISGylation. Our results demonstrate that ISGylation inhibits HCMV growth at multiple steps and that HCMV has evolved countermeasures to suppress ISG15 transcription and protein ISGylation, highlighting the importance of the interplay between virus and ISGylation in productive viral infection. |
format | Online Article Text |
id | pubmed-5001722 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2016 |
publisher | Public Library of Science |
record_format | MEDLINE/PubMed |
spelling | pubmed-50017222016-09-12 Consecutive Inhibition of ISG15 Expression and ISGylation by Cytomegalovirus Regulators Kim, Ye Ji Kim, Eui Tae Kim, Young-Eui Lee, Myoung Kyu Kwon, Ki Mun Kim, Keun Il Stamminger, Thomas Ahn, Jin-Hyun PLoS Pathog Research Article Interferon-stimulated gene 15 (ISG15) encodes an ubiquitin-like protein that covalently conjugates protein. Protein modification by ISG15 (ISGylation) is known to inhibit the replication of many viruses. However, studies on the viral targets and viral strategies to regulate ISGylation-mediated antiviral responses are limited. In this study, we show that human cytomegalovirus (HCMV) replication is inhibited by ISGylation, but the virus has evolved multiple countermeasures. HCMV-induced ISG15 expression was mitigated by IE1, a viral inhibitor of interferon signaling, however, ISGylation was still strongly upregulated during virus infection. RNA interference of UBE1L (E1), UbcH8 (E2), Herc5 (E3), and UBP43 (ISG15 protease) revealed that ISGylation inhibits HCMV growth by downregulating viral gene expression and virion release in a manner that is more prominent at low multiplicity of infection. A viral regulator pUL26 was found to interact with ISG15, UBE1L, and Herc5, and be ISGylated. ISGylation of pUL26 regulated its stability and inhibited its activities to suppress NF-κB signaling and complement the growth of UL26-null mutant virus. Moreover, pUL26 reciprocally suppressed virus-induced ISGylation independent of its own ISGylation. Consistently, ISGylation was more pronounced in infections with the UL26-deleted mutant virus, whose growth was more sensitive to IFNβ treatment than that of the wild-type virus. Therefore, pUL26 is a viral ISG15 target that also counteracts ISGylation. Our results demonstrate that ISGylation inhibits HCMV growth at multiple steps and that HCMV has evolved countermeasures to suppress ISG15 transcription and protein ISGylation, highlighting the importance of the interplay between virus and ISGylation in productive viral infection. Public Library of Science 2016-08-26 /pmc/articles/PMC5001722/ /pubmed/27564865 http://dx.doi.org/10.1371/journal.ppat.1005850 Text en © 2016 Kim et al http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited. |
spellingShingle | Research Article Kim, Ye Ji Kim, Eui Tae Kim, Young-Eui Lee, Myoung Kyu Kwon, Ki Mun Kim, Keun Il Stamminger, Thomas Ahn, Jin-Hyun Consecutive Inhibition of ISG15 Expression and ISGylation by Cytomegalovirus Regulators |
title | Consecutive Inhibition of ISG15 Expression and ISGylation by Cytomegalovirus Regulators |
title_full | Consecutive Inhibition of ISG15 Expression and ISGylation by Cytomegalovirus Regulators |
title_fullStr | Consecutive Inhibition of ISG15 Expression and ISGylation by Cytomegalovirus Regulators |
title_full_unstemmed | Consecutive Inhibition of ISG15 Expression and ISGylation by Cytomegalovirus Regulators |
title_short | Consecutive Inhibition of ISG15 Expression and ISGylation by Cytomegalovirus Regulators |
title_sort | consecutive inhibition of isg15 expression and isgylation by cytomegalovirus regulators |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5001722/ https://www.ncbi.nlm.nih.gov/pubmed/27564865 http://dx.doi.org/10.1371/journal.ppat.1005850 |
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