Overexpression of ACE2 enhanced SARS-CoV-2 infection in A549 cells, while depletion of MYH9 in ACE2-A549 cells significantly reduced SARS-CoV-2 pseudovirus infection (Fig. 4F) or authentic SARS-CoV-2 infection (Fig. 5 A and B), indicating the important role of MYH9 acting as an ACE2 coreceptor during SARS-CoV-2 infection. This evidence concerns the gene ACE2 and severe acute respiratory syndrome.