CHEK1 and Fanconi anemia: This mechanism may largely be important for types of damage that are dependent upon the Fanconi anemia pathway for repair, including that caused by mitomycin C. Similarly, USP7 regulates CHK1 most efficiently under conditions that activate ATM, which results in the stabilization of ZEB1, a factor that enhances the USP7–CHK1 interaction (30, 31).