SMAD3 and acute kidney injury: Our previous study has demonstrated that Smad3 can cause TEC death and AKI via the G1 cell cycle arrest mechanism by directly interacting with the cyclin‐dependent kinase inhibitors (p21/p27).[30, 33] Here we examined whether AKI induced by kidney‐specifically overexpressing SARS‐CoV‐2 N protein is associated with activation of Smad3‐p21‐dependent G1 cell cycle arrest pathway in both normal and ischemic stress conditions.