ACE2 and infection: To better understand the host response to SARS-CoV-2 infection, we quantified changes in protein and phosphosite abundance in A549 human lung epithelial cells transduced to express ACE2 (A549-ACE2) infected with SARS-CoV-2 at a multiplicity of infection (MOI) of 0.1 for 24 hours (Fig. 1A).