Skip to main content
. Author manuscript; available in PMC: 2021 Jul 26.
Published in final edited form as: Curr Opin Virol. 2021 Jul 24;50:49–58. doi: 10.1016/j.coviro.2021.07.004

Figure 1. SARS-CoV-2 entry is dependent on proteolytic cleavage of the spike glycoprotein mediated through early or late entry pathways.

Figure 1.

(A) Schematic diagram of spike glycoprotein highlighting S1/S2 and S2’ cleavage sites. Uniport SARS-CoV-2 spike annotations were used and schematic was generated in Biorender. (B) Structure of spike glycoprotein depicting cleavage locations and select mutants. SARS-CoV-2 structure generated using SWISS-MODEL to depict the S1/S2 cleavage sites and annotated using Pymol. S1/S2 region is depicted in green and S2’ region is in red. Spheres depict the location of select mutations discussed in the text: G614, Q677, and P681. (C) Proteolytic activation of SARS-CoV-2 spike mediates early and late entry pathways. Pathways 1 and 2 show early entry at the cell surface facilitated by exogenous or cell surface proteases, respectively. Pathway 3 shows late entry facilitated by endosomal proteases such as cathepsin L. Model generated using Biorender and adapted from Oguntuyo and Stevens et al.