Efficient Activation of the Severe Acute Respiratory Syndrome Coronavirus Spike Protein by the Transmembrane Protease TMPRSS2
Efficient Activation of the Severe Acute Respiratory Syndrome Coronavirus Spike Protein by the Transmembrane Protease TMPRSS2
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DOI：
10.1128/jvi.01542-10
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发表时间：
2010-12-01
影响因子：
5.4
通讯作者：
Taguchi, Fumihiro
中科院分区：
文献类型：
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作者：
Matsuyama, Shutoku;Nagata, Noriyo;Taguchi, Fumihiro
严重急性呼吸综合征冠状病毒（SARS-CoV）受体（一种血管紧张素转换酶2（ACE 2））的分布与SARS-CoV细胞在肺中的嗜性并不严格相关;因此，已预测其他细胞因子是激活病毒感染所必需的。在本研究中，我们确定了跨膜蛋白酶丝氨酸2（TMPRSS 2），其表达与SARS冠状病毒感染肺上叶。在表达TMPRSS 2的Vero细胞中，SARS-CoV感染诱导了大的合胞体。此外，亲溶酶体试剂不能抑制，而七肽重复肽有效地抑制病毒进入细胞，表明TMPRSS 2影响细胞表面的S蛋白并诱导病毒-质膜融合。另一方面，在表达TMPRSS 2的细胞中产生病毒不会导致S蛋白切割或所得病毒的感染性增加。因此，TMPRSS 2影响病毒的进入，但不影响病毒复制的其他阶段。我们假设TMPRSS 2维斯S蛋白的空间取向是这种现象的关键机制。为了验证这一点，在用不同颜色的荧光探针标记的细胞中表达TMPRSS 2和S蛋白，并测试这些细胞之间的细胞-细胞融合。结果表明，TMPRSS 2需要在相对的（靶）细胞膜中表达以激活S蛋白，而不是在生产细胞中表达，如在甲型流感病毒和偏肺病毒中所发现的。这是首次报道TMPRSS 2在靶细胞中是激活病毒融合蛋白所必需的，而不是在细胞中合成和转运到细胞表面的S蛋白所必需的。我们的研究结果表明，肺组织中表达的TMPRSS 2可能是决定SARS冠状病毒感染的初始部位的病毒嗜性和致病性的决定因素。
The distribution of the severe acute respiratory syndrome coronavirus (SARS-CoV) receptor, an angiotensin-converting enzyme 2 (ACE2), does not strictly correlate with SARS-CoV cell tropism in lungs; therefore, other cellular factors have been predicted to be required for activation of virus infection. In the present study, we identified transmembrane protease serine 2 (TMPRSS2), whose expression does correlate with SARS-CoV infection in the upper lobe of the lung. In Vero cells expressing TMPRSS2, large syncytia were induced by SARS-CoV infection. Further, the lysosome-tropic reagents failed to inhibit, whereas the heptad repeat peptide efficiently inhibited viral entry into cells, suggesting that TMPRSS2 affects the S protein at the cell surface and induces virus-plasma membrane fusion. On the other hand, production of virus in TMPRSS2-expressing cells did not result in S-protein cleavage or increased infectivity of the resulting virus. Thus, TMPRSS2 affects the entry of virus but not other phases of virus replication. We hypothesized that the spatial orientation of TMPRSS2 vis-a-vis S protein is a key mechanism underling this phenomenon. To test this, the TMPRSS2 and S proteins were expressed in cells labeled with fluorescent probes of different colors, and the cell-cell fusion between these cells was tested. Results indicate that TMPRSS2 needs to be expressed in the opposing (target) cell membrane to activate S protein rather than in the producer cell, as found for influenza A virus and metapneumoviruses. This is the first report of TMPRSS2 being required in the target cell for activation of a viral fusion protein but not for the S protein synthesized in and transported to the surface of cells. Our findings suggest that the TMPRSS2 expressed in lung tissues may be a determinant of viral tropism and pathogenicity at the initial site of SARS-CoV infection.