Different residues in the SARS-CoV spike protein determine cleavage and activation by the host cell protease TMPRSS2

PLoS One. 2017 Jun 21;12(6):e0179177. doi: 10.1371/journal.pone.0179177. eCollection 2017.

Abstract

The spike (S) protein of severe acute respiratory syndrome coronavirus (SARS-CoV) mediates viral entry into target cells. Cleavage and activation of SARS S by a host cell protease is essential for infectious viral entry and the responsible enzymes are potential targets for antiviral intervention. The type II transmembrane serine protease TMPRSS2 cleaves and activates SARS S in cell culture and potentially also in the infected host. Here, we investigated which determinants in SARS S control cleavage and activation by TMPRSS2. We found that SARS S residue R667, a previously identified trypsin cleavage site, is also required for S protein cleavage by TMPRSS2. The cleavage fragments produced by trypsin and TMPRSS2 differed in their decoration with N-glycans, suggesting that these proteases cleave different SARS S glycoforms. Although R667 was required for SARS S cleavage by TMPRSS2, this residue was dispensable for TMPRSS2-mediated S protein activation. Conversely, residue R797, previously reported to be required for SARS S activation by trypsin, was dispensable for S protein cleavage but required for S protein activation by TMPRSS2. Collectively, these results show that different residues in SARS S control cleavage and activation by TMPRSS2, suggesting that these processes are more complex than initially appreciated.

MeSH terms

  • HEK293 Cells
  • Host-Pathogen Interactions
  • Humans
  • Mutation / genetics
  • Protein Transport
  • Serine Endopeptidases / genetics
  • Serine Endopeptidases / metabolism*
  • Spike Glycoprotein, Coronavirus / genetics
  • Spike Glycoprotein, Coronavirus / metabolism*
  • Virus Internalization

Substances

  • Spike Glycoprotein, Coronavirus
  • spike glycoprotein, SARS-CoV
  • Serine Endopeptidases
  • TMPRSS2 protein, human

Grants and funding

The study was supported by the Leibniz Association (Graduate School for Emerging Infectious Diseases). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.