ACE2 and infection: Given that the A549‐ACE2 cells do not express TMPRSS2 and that their infection was not only reduced upon ADAM17 knock‐out, but also with a lysosomal cathepsin inhibitor, we propose that ADAM17 acts in the lysosomal entry pathway, either at the plasma membrane just before endocytosis or after endocytosis (Fig 6A).