title: SARS-CoV nucleocapsid protein binds to hUbc9, a ubiquitin conjugating enzyme of the sumoylation system.
abstract: SARS-CoV is a newly identified coronavirus (CoV) that causes severe acute respiratory syndrome (SARS). The SARS-CoV nucleocapsid (N) protein is an important structural and functional protein. To identify cellular proteins that interact with the SARS-CoV N protein and to elucidate the possible involvement of N protein in SARS-CoV pathogenesis, a human lymphocyte cDNA library was screened using a yeast two-hybrid system assay. hUbc9, a ubiquitin conjugating enzyme of sumoylation system, was found to interact specifically with the N protein, implying the post-translational sumoylation of the N protein. Mapping studies localized the critical N sequences for this interaction to amino acids 170-210, which includes the SR-rich motif. However, the consensus motif of sumoylation GK(62)EE in the N protein is not responsible for binding to hUbc9. Mutations of hUbc9 at the enzyme active site C93A or C93S severely impair the interaction with the N protein. The two proteins were also shown to colocalize in the cytoplasm of the transfected 293T cells. This is the first report demonstrating the interaction of hUbc9 with a structural protein of plus-strand RNA viruses, indicating a new drug target for SARS-CoV.
authors.affiliation: Center for Molecular Virology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Fan
authors.forename: Yue
authors.initials: Y
authors.lastname: Zhuo
authors.forename: Xinyu
authors.initials: X
authors.lastname: Tan
authors.forename: Zhi
authors.initials: Z
authors.lastname: Zhou
authors.forename: Jiangang
authors.initials: J
authors.lastname: Yuan
authors.forename: Boqin
authors.initials: B
authors.lastname: Qiang
authors.forename: Jinghua
authors.initials: J
authors.lastname: Yan
authors.forename: Xiaozhong
authors.initials: X
authors.lastname: Peng
authors.forename: George F
authors.initials: GF
authors.lastname: Gao
mesh_terms: D001665:Binding Sites; D002460:Cell Line; D000086462:Coronavirus Nucleocapsid Proteins; D006801:Humans; D019590:Nucleocapsid Proteins / Q000378:metabolism*; D011485:Protein Binding; D045473:Severe acute respiratory syndrome-related coronavirus / Q000378:metabolism*; D025841:Small Ubiquitin-Related Modifier Proteins / Q000378:metabolism*; D020798:Two-Hybrid System Techniques; D025801:Ubiquitin / Q000378:metabolism*; D044763:Ubiquitin-Conjugating Enzymes / Q000378:metabolism*; D000098843:Ubiquitin-Conjugating Enzyme UBC9
chemical_list: D000086462:Coronavirus Nucleocapsid Proteins; D019590:Nucleocapsid Proteins; D025841:Small Ubiquitin-Related Modifier Proteins; D025801:Ubiquitin; D044763:Ubiquitin-Conjugating Enzymes; D000098843:Ubiquitin-Conjugating Enzyme UBC9