This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Kawase, M.
Right arrow Articles by Taguchi, F.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Kawase, M.
Right arrow Articles by Taguchi, F.

 Previous Article  |  Next Article 

Journal of Virology, January 2009, p. 712-721, Vol. 83, No. 2
0022-538X/09/$08.00+0     doi:10.1128/JVI.01933-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Protease-Mediated Entry via the Endosome of Human Coronavirus 229E{triangledown}

Miyuki Kawase, Kazuya Shirato, Shutoku Matsuyama, and Fumihiro Taguchi*

Laboratory of Respiratory Viral Infections, Department of Virology III, National Institute of Infectious Diseases, Musashi-Murayama, 208-0011 Tokyo, Japan

Received 15 September 2008/ Accepted 21 October 2008

Human coronavirus 229E, classified as a group I coronavirus, utilizes human aminopeptidase N (APN) as a receptor; however, its entry mechanism has not yet been fully elucidated. We found that HeLa cells infected with 229E via APN formed syncytia when treated with trypsin or other proteases but not in a low-pH environment, a finding consistent with syncytium formation by severe acute respiratory syndrome coronavirus (SARS-CoV). In addition, trypsin induced cleavage of the 229E S protein. By using infectious viruses and pseudotyped viruses bearing the 229E S protein, we found that its infection was profoundly blocked by lysosomotropic agents as well as by protease inhibitors that also prevented infection with SARS-CoV but not that caused by murine coronavirus mouse hepatitis virus strain JHMV, which enters cells directly from the cell surface. We found that cathepsin L (CPL) inhibitors blocked 229E infection the most remarkably among a variety of protease inhibitors tested. Furthermore, 229E infection was inhibited in CPL knockdown cells by small interfering RNA, compared with what was seen for a normal counterpart producing CPL. However, its inhibition was not so remarkable as that found with SARS-CoV infection, which seems to indicate that while CPL is involved in the fusogenic activation of 229E S protein in endosomal infection, not-yet-identified proteases could also play a part in that activity. We also found 229E virion S protein to be cleaved by CPL. Furthermore, as with SARS-CoV, 229E entered cells directly from the cell surface when cell-attached viruses were treated with trypsin. These findings suggest that 229E takes an endosomal pathway for cell entry and that proteases like CPL are involved in this mode of entry.

* Corresponding author. Mailing address: Laboratory of Viral Respiratory Infections, Department of Virology III, National Institute of Infectious Diseases, Musashi-Murayama, 208-0011 Tokyo, Japan. Phone: 81-42-561-0771, ext. 3533. Fax: 81-42-567-5631. E-mail: ftaguchi{at}nih.go.jp

{triangledown} Published ahead of print on 29 October 2008.

Journal of Virology, January 2009, p. 712-721, Vol. 83, No. 2
0022-538X/09/$08.00+0     doi:10.1128/JVI.01933-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Yamada, Y., Liu, D. X. (2009). Proteolytic Activation of the Spike Protein at a Novel RRRR/S Motif Is Implicated in Furin-Dependent Entry, Syncytium Formation, and Infectivity of Coronavirus Infectious Bronchitis Virus in Cultured Cells. J. Virol. 83: 8744-8758 [Abstract] [Full Text]  


Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»