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A Distinct Role of Riplet-Mediated K63-Linked Polyubiquitination of the RIG-I Repressor Domain in Human Antiviral Innate Immune Responses
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| Title: | A Distinct Role of Riplet-Mediated K63-Linked Polyubiquitination of the RIG-I Repressor Domain in Human Antiviral Innate Immune Responses |
| Authors: | Oshiumi, Hiroyuki Browse this author →KAKEN DB | | Miyashita, Moeko Browse this author | | Matsumoto, Misako Browse this author →KAKEN DB | | Seya, Tsukasa Browse this author →KAKEN DB |
| Issue Date: | Aug-2013 |
| Publisher: | Public library science |
| Journal Title: | Plos pathogens |
| Volume: | 9 |
| Issue: | 8 |
| Start Page: | e1003533 |
| Publisher DOI: | 10.1371/journal.ppat.1003533 |
| PMID: | 23950712 |
| Abstract: | The innate immune system is essential for controlling viral infections, but several viruses have evolved strategies to escape innate immunity. RIG-I is a cytoplasmic viral RNA sensor that triggers the signal to induce type I interferon production in response to viral infection. RIG-I activation is regulated by the K63-linked polyubiquitin chain mediated by Riplet and TRIM25 ubiquitin ligases. TRIM25 is required for RIG-I oligomerization and interaction with the IPS-1 adaptor molecule. A knockout study revealed that Riplet was essential for RIG-I activation. However the molecular mechanism underlying RIG-I activation by Riplet remains unclear, and the functional differences between Riplet and TRIM25 are also unknown. A genetic study and a pull-down assay indicated that Riplet was dispensable for RIG-I RNA binding activity but required for TRIM25 to activate RIG-I. Mutational analysis demonstrated that Lys-788 within the RIG-I repressor domain was critical for Riplet-mediated K63-linked polyubiquitination and that Riplet was required for the release of RIG-I autorepression of its N-terminal CARDs, which leads to the association of RIG-I with TRIM25 ubiquitin ligase and TBK1 protein kinase. Our data indicate that Riplet is a prerequisite for TRIM25 to activate RIG-I signaling. We investigated the biological importance of this mechanism in human cells and found that hepatitis C virus (HCV) abrogated this mechanism. Interestingly, HCV NS3-4A proteases targeted the Riplet protein and abrogated endogenous RIG-I polyubiquitination and association with TRIM25 and TBK1, emphasizing the biological importance of this mechanism in human antiviral innate immunity. In conclusion, our results establish that Riplet-mediated K63-linked polyubiquitination released RIG-I RD autorepression, which allowed the access of positive factors to the RIG-I protein. |
| Rights: | http://creativecommons.org/licenses/by/3.0/ |
| Type: | article |
| URI: | http://hdl.handle.net/2115/53342 |
| Appears in Collections: | 医学院・医学研究院 (Graduate School of Medicine / Faculty of Medicine) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 押海 裕之
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