title: Interaction of NS2 with AIMP2 facilitates the switch from ubiquitination to SUMOylation of M1 in influenza A virus-infected cells.
abstract: Influenza A viruses (IAVs) rely on host factors to support their life cycle, as viral proteins hijack or interact with cellular proteins to execute their functions. Identification and understanding of these factors would increase our knowledge of the molecular mechanisms manipulated by the viruses. In this study, we searched for novel binding partners of the influenza A virus NS2 protein, the nuclear export protein responsible for overcoming host range restriction, by a yeast two-hybrid screening assay and glutathione S-transferase-pulldown and coimmunoprecipitation assays and identified AIMP2, a potent tumor suppressor that usually functions to regulate protein stability, as one of the major NS2-binding candidates. We found that the presence of NS2 protected AIMP2 from ubiquitin-mediated degradation in NS2-transfected cells and AIMP2 functioned as a positive regulator of IAV replication. Interestingly, AIMP2 had no significant effect on NS2 but enhanced the stability of the matrix protein M1. Further, we provide evidence that AIMP2 recruitment switches the modification of M1 from ubiquitination to SUMOylation, which occurs on the same attachment site (K242) on M1 and thereby promotes M1-mediated viral ribonucleoprotein complex nuclear export to increase viral replication. Collectively, our results reveal a new mechanism of AIMP2 mediation of influenza virus replication.
  
  
  OBJECTIVE
  Although the ubiquitination of M1 during IAV infection has been observed, the precise modification site and the molecular consequences of this modification remain obscure. Here, we demonstrate for the first time that ubiquitin and SUMO compete for the same lysine (K242) on M1 and the interaction of NS2 with AIMP2 facilitates the switch of the M1 modification from ubiquitination to SUMOylation, thus increasing viral replication.
authors.affiliation: CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
authors.forename: Shijuan
authors.initials: S
authors.lastname: Gao
authors.affiliation: Anhui University, Hefei, Anhui Province, China.
authors.forename: Jiaoxiang
authors.initials: J
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, China.
authors.forename: Ran-Yi
authors.initials: RY
authors.lastname: Liu
authors.affiliation: CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
authors.forename: Jiandong
authors.initials: J
authors.lastname: Li
authors.affiliation: CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
authors.forename: Liping
authors.initials: L
authors.lastname: Song
authors.affiliation: Center for Biological Imaging, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Teng
authors.affiliation: CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
authors.forename: Chunjie
authors.initials: C
authors.lastname: Sheng
authors.affiliation: CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
authors.forename: Dong
authors.initials: D
authors.lastname: Liu
authors.affiliation: Anhui University, Hefei, Anhui Province, China.
authors.forename: Chen
authors.initials: C
authors.lastname: Yao
authors.affiliation: Anhui University, Hefei, Anhui Province, China.
authors.forename: Huiming
authors.initials: H
authors.lastname: Chen
authors.affiliation: CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Jiang
authors.affiliation: CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, China shuaichen2010@hotmail.com hwenl@mail.sysu.edu.cn.
authors.forename: Shuai
authors.initials: S
authors.lastname: Chen
authors.affiliation: CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, China Key Laboratory of Tumor Targeted Drug in Guangdong Province, Guangzhou Double Bioproducts Co., Ltd., Guangzhou, China shuaichen2010@hotmail.com hwenl@mail.sysu.edu.cn.
authors.forename: Wenlin
authors.initials: W
authors.lastname: Huang
mesh_terms: D002460:Cell Line; D002498:Centrifugation; D054884:Host-Pathogen Interactions; D006801:Humans; D047468:Immunoprecipitation; D009980:Influenza A virus / Q000502:physiology*; D009687:Nuclear Proteins / Q000378:metabolism*; D011485:Protein Binding; D025941:Protein Interaction Mapping; D058207:Sumoylation; D020798:Two-Hybrid System Techniques; D054875:Ubiquitination; D014763:Viral Matrix Proteins / Q000378:metabolism*; D017361:Viral Nonstructural Proteins / Q000378:metabolism*; D014779:Virus Replication
chemical_list: C575685:AIMP2 protein, human; C488936:M1 protein, Influenza A virus; C556232:NS2 protein, influenza virus A; D009687:Nuclear Proteins; D014763:Viral Matrix Proteins; D017361:Viral Nonstructural Proteins