Figure 1.

SARS-CoV-2 infection and entrance via a plausible pathway. Using the S protein projecting from the viral particle, SARS-CoV-2 may first engage with the HSPGs on the surface of susceptible cells early in the infection cycle. The virus’s subsequent interaction with the high-affinity entry receptor ACE2 may be facilitated by this initial attachment. By cleaving the S protein at the S1/S2 and/or S2’ sites, the transmembrane protease serine 2 (TMPRSS2) on the host cell surface and other host cell proteases may facilitate viral entry [53]. Adapted with permission from ref. [53]. Copyright 2021 Science China Press.