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PSMB1 Inhibits the Replication of Porcine Reproductive and Respiratory Syndrome Virus by Recruiting NBR1 To Degrade Nonstructural Protein 12 by Autophagy. J Virol 2023; 97:e0166022. [PMID: 36602366 PMCID: PMC9888268 DOI: 10.1128/jvi.01660-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The nonstructural proteins (Nsps) of porcine reproductive and respiratory syndrome virus (PRRSV) play essential roles in virus replication-a multistep process that requires the participation of host factors. It is of great significance for the development of antiviral drugs to characterize the host proteins that interact with PRRSV Nsps and their functions in PRRSV replication. Here, we determined that proteasome subunit β type 1 (PSMB1) interacted with viral Nsp12 to inhibit PRRSV replication in target and permissive cells. PSMB1 could be downregulated by PRRSV infection through interaction with the transcription factor EBF1. Proteasome and autophagy inhibitor assays showed that PSMB1 was regulated by the autophagic pathway to degrade Nsp12. Cotransfection of PSMB1 and Nsp12 increased the level of intracellular autophagy; both molecules were colocated in lysosomes. We also found that the selective autophagy cargo receptor protein NBR1 and E3 ubiquitin ligase STUB1 interacted with PSMB1 and Nsp12, respectively, in the autophagic degradation of Nsp12. Furthermore, the degradation of Nsp12 by PSMB1 was mainly dependent on the ubiquitination of Nsp12 at lysine site 130. Our results indicate for the first time that PSMB1 is an anti-PRRSV host protein that inhibits the replication of PRRSV by degradation of Nsp12 through the selective autophagy pathway. IMPORTANCE PRRS is a major threat to the global pig industry and urgently requires an effective and sustainable control strategy. PRRSV Nsps have important roles in viral RNA synthesis, proteinase activity, induction of replication-associated membrane rearrangements, replicative endoribonuclease activity, determination of virulence, and regulation of host immune response. Research associated with PRRSV Nsps can provide vital guidance to modify the PRRSV genome through reverse genetics in the development of vaccines and diagnostics. The function of Nsp12, which generally plays essential roles in virus replication, remains unclear. We demonstrated that PSMB1 interacted with and degraded Nsp12 through an autophagic pathway to inhibit PRRSV replication. Our data confirmed a novel antiviral function of PSMB1 and allowed us to elaborate on the roles of Nsp12 in PRRSV pathogenesis. These findings suggest a valid and highly conserved candidate target for the development of novel therapies and more effective vaccines and demonstrate the complex cross talk between selective autophagy and PRRSV infection.
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Bai Y, Li L, Shan T, Zhang Y, Chen X, Gao F, Jiang Y, Zhou Y, Li G, Yu L, Kong N, Ma Z, Tong G. Proteasomal degradation of nonstructural protein 12 by RNF114 suppresses porcine reproductive and respiratory syndrome virus replication. Vet Microbiol 2020; 246:108746. [PMID: 32605740 DOI: 10.1016/j.vetmic.2020.108746] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 05/31/2020] [Accepted: 05/31/2020] [Indexed: 11/20/2022]
Abstract
Porcine reproductive and respiratory syndrome virus (PRRSV) poses a significant threat to the swine industry worldwide, and the development of effective and sustainable measures to control PRRSV transmission remains a pressing problem. The function of PRRSV nonstructural protein 12 (Nsp12), which might play essential roles in viral replication and production, remains unknown. In this study, we identified a new host-restricted factor, porcine RING finger protein 114 (RNF114), as an inhibitor of PRRSV replication through its degradation of viral Nsp12. Western blot, quantitative real-time polymerase chain reaction, and viral titer assays indicated that RNF114 overexpression suppressed PRRSV replication, whereas RNF114 knockdown increased viral titer and nucleocapsid protein levels. Additionally, we observed that PPRSV infection led to increased RNF114 levels during the middle and late phases of infection in both porcine alveolar macrophages and MARC-145 cells. Moreover, screening of PRRSV Nsps showed that RNF114 interacted with viral Nsp12, and that RNF114-specific anti-PRRSV effects were associated with its ubiquitin ligase activity, which involves K27-linked polyubiquitination and degradation of Nsp12 through a proteasome-dependent pathway. These findings identified RNF114 as a critical regulator of PRRSV replication and offer insights into the roles of Nsp12 in PRRSV pathogenesis.
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Affiliation(s)
- Yuanzhe Bai
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, PR China
| | - Liwei Li
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, PR China; Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonose, Yangzhou University, Yangzhou, 225009, PR China
| | - Tongling Shan
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, PR China
| | - Yujiao Zhang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, PR China
| | - Xiaoyong Chen
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, PR China
| | - Fei Gao
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, PR China
| | - Yifeng Jiang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, PR China
| | - Yanjun Zhou
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, PR China
| | - Guoxin Li
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, PR China
| | - Lingxue Yu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, PR China
| | - Ning Kong
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, PR China
| | - Zhiyong Ma
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, PR China
| | - Guangzhi Tong
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, PR China; Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonose, Yangzhou University, Yangzhou, 225009, PR China.
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