Middle East Respiratory Syndrome Coronavirus Spike Protein Is Not Activated Directly by Cellular Furin during Viral Entry into Target Cells
In: Journal of Virology, Jg. 92 (2018-07-18), Heft 19
Online
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Zugriff:
Middle East respiratory syndrome coronavirus (MERS-CoV) utilizes host cellular proteases to enter cells. A previous report shows that furin, which is distributed mainly in the Golgi apparatus and cycled to the cell surface and endosomes, proteolytically activates the MERS-CoV spike (S) protein following receptor binding to mediate fusion between the viral and cellular membranes. In this study, we reexamined furin usage by MERS-CoV using a real-time PCR-based virus cell entry assay after inhibition of cellular proteases. We found that the furin inhibitor dec-RVKR-CMK blocked entry of MERS-CoV harboring an S protein lacking furin cleavage sites; it even blocked entry into furin-deficient LoVo cells. In addition, dec-RVKR-CMK inhibited not only the enzymatic activity of furin but also those of cathepsin L, cathepsin B, trypsin, papain, and TMPRSS2. Furthermore, a virus cell entry assay and a cell-cell fusion assay provided no evidence that the S protein was activated by exogenous furin. Therefore, we conclude that furin does not play a role in entry of MERS-CoV into cells and that the inhibitory effect of dec-RVKR-CMK is specific for TMPRSS2 and cathepsin L rather than furin. IMPORTANCE Previous studies using the furin inhibitor dec-RVKR-CMK suggest that MERS-CoV utilizes a cellular protease, furin, to activate viral glycoproteins during cell entry. However, we found that dec-RVKR-CMK inhibits not only furin but also other proteases. Furthermore, we found no evidence that MERS-CoV uses furin. These findings suggest that previous studies in the virology field based on dec-RVKR-CMK should be reexamined carefully. Here we describe appropriate experiments that can be used to assess the effect of protease inhibitors on virus cell entry.
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Middle East Respiratory Syndrome Coronavirus Spike Protein Is Not Activated Directly by Cellular Furin during Viral Entry into Target Cells
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Autor/in / Beteiligte Person: | Matsuyama, Shutoku ; Kawase, Miyuki ; Terada, Yutaka ; Shirato, Kazuya ; Kawachi, Kengo ; Kamitani, Wataru ; Fukushi, Shuetsu |
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Zeitschrift: | Journal of Virology, Jg. 92 (2018-07-18), Heft 19 |
Veröffentlichung: | American Society for Microbiology, 2018 |
Medientyp: | unknown |
ISSN: | 1098-5514 (print) ; 0022-538X (print) |
DOI: | 10.1128/jvi.00683-18 |
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