SARS-CoV nucleocapsid protein binds to hUbc9, a ubiquitin conjugating enzyme of the sumoylation system
✍ Scribed by Zheng Fan; Yue Zhuo; Xinyu Tan; Zhi Zhou; Jiangang Yuan; Boqin Qiang; Jinghua Yan; Xiaozhong Peng; George F. Gao
- Publisher
- John Wiley and Sons
- Year
- 2006
- Tongue
- English
- Weight
- 517 KB
- Volume
- 78
- Category
- Article
- ISSN
- 0146-6615
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✦ Synopsis
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 posttranslational 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.