What are the receptors used by SARS-CoV-2 for cell entry?
SARS-CoV-2 binds to ACE2 via its spike protein to enter human
cells8. Cell entry is facilitated by the host serine
protease TMPRSS2 that cleaves the spike protein into S1 and S2
fragments, thus enabling cellular membrane fusion (Figure
1 ).9 ACE2 is highly expressed in the lungs, small
intestine, kidney and heart, but not in innate and adaptive immune
cells.10-13 SARS-CoV-2 also binds to CD147 (known as
basigin or extracellular matrix metalloproteinase inducer), which is
expressed in human airway and kidney epithelium, as well as in innate
cells and lymphocytes14. Receptors reported for other
coronaviruses, such as CD26, aminopeptidase N and glutamyl
aminopeptidase could be utilized by SARS-CoV-2 for cell
invasion.13,15,16