What is the name of the human cell surface receptor to which the SARS-CoV-2 spike protein binds to initiate infection?

What is the name of the human cell surface receptor to which the SARS-CoV-2 spike protein binds to initiate infection?

• A. CD4
• B. ACE2
• C. CCR5
• D. CXCR4

Answer: (B)

The main concept here is how the virus starts infection by attaching to a specific receptor on human cells. The SARS-CoV-2 spike protein binds to ACE2 on the surface of host cells. This binding is the first step that lets the virus dock and then, with the help of host proteases like TMPRSS2, undergo the conformational changes needed to fuse the viral and cellular membranes so the viral RNA can enter the cell. ACE2 is a receptor widely expressed in the respiratory tract, which helps explain where the virus can initiate infection. The other options are receptors used by different viruses (notably HIV) to enter certain immune cells, so they aren’t the receptors SARS-CoV-2 uses.

The main concept here is how the virus starts infection by attaching to a specific receptor on human cells. The SARS-CoV-2 spike protein binds to ACE2 on the surface of host cells. This binding is the first step that lets the virus dock and then, with the help of host proteases like TMPRSS2, undergo the conformational changes needed to fuse the viral and cellular membranes so the viral RNA can enter the cell.

ACE2 is a receptor widely expressed in the respiratory tract, which helps explain where the virus can initiate infection. The other options are receptors used by different viruses (notably HIV) to enter certain immune cells, so they aren’t the receptors SARS-CoV-2 uses.