ACE2 and infection: Further in vitro infection experiments confirmed that overexpression of ASGR1 and KREMEN1 can promote SARS-CoV-2 pseudoviral infection in ACE2 knockout cells, indicating that ASGR1 and KREMEN1 can act as entry receptors in ACE2-independent cell lines and directly mediate SARS-CoV-2 infection independent of ACE2.