USP39 and viral infectious disease: Another reported E protein deubiquitinase, USP39, was enhanced in expression after viral infection.[53] But in different cells such as A549‐ACE2 and Calu3 cells, we confirmed that total protein levels of USP33 were not changed in response to viral infection, suggesting a different strategy for E hijacking of USP33 from USP39 (Figure S2E, Supporting Information).