Open AccessFurin cleavage of SARS-CoV-2 Spike promotes but is not essential for infection and cell-cell fusion
Author(s) -
Guido Papa,
Donna L. Mallery,
Anna Albecka,
Lawrence G. Welch,
Jérôme CattinOrtolá,
Jakub Lupták,
David Paul,
Harvey T. McMahon,
Ian Goodfellow,
Andrew Carter,
Sean Munro,
Leo C. James
Publication year - 2021
Publication title -
plos pathogens
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.719
H-Index - 206
eISSN - 1553-7374
pISSN - 1553-7366
DOI - 10.1371/journal.ppat.1009246
Subject(s) - furin , cell fusion , syncytium , virology , lipid bilayer fusion , virus , infectivity , biology , coronavirus , microbiology and biotechnology , hek 293 cells , cleavage (geology) , viral entry , cell , mutant , viral envelope , cell culture , biochemistry , viral replication , gene , genetics , covid-19 , enzyme , medicine , paleontology , disease , pathology , fracture (geology) , infectious disease (medical specialty)
Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2) infects cells by binding to the host cell receptor ACE2 and undergoing virus-host membrane fusion. Fusion is triggered by the protease TMPRSS2, which processes the viral Spike (S) protein to reveal the fusion peptide. SARS-CoV-2 has evolved a multibasic site at the S1-S2 boundary, which is thought to be cleaved by furin in order to prime S protein for TMPRSS2 processing. Here we show that CRISPR-Cas9 knockout of furin reduces, but does not prevent, the production of infectious SARS-CoV-2 virus. Comparing S processing in furin knockout cells to multibasic site mutants reveals that while loss of furin substantially reduces S1-S2 cleavage it does not prevent it. SARS-CoV-2 S protein also mediates cell-cell fusion, potentially allowing virus to spread virion-independently. We show that loss of furin in either donor or acceptor cells reduces, but does not prevent, TMPRSS2-dependent cell-cell fusion, unlike mutation of the multibasic site that completely prevents syncytia formation. Our results show that while furin promotes both SARS-CoV-2 infectivity and cell-cell spread it is not essential, suggesting furin inhibitors may reduce but not abolish viral spread.