FIG 8.

MCL-1-deficient cells are defective in the DNA repair pathway. The left side shows that translocation of MCL-1 to the nucleus contributes to repair of damaged DNA by the HR pathway, whereas the right side shows that cells deficient in MCL-1 increase the recruitment of 53BP1/RIF1 complex at the DNA damage sites, which prevents the repair of DNA by the HR pathway. Our results show that MCL-1 regulates three important steps in the HR pathway: (i) increase in 53BP1/RIF1 localization at the DNA damage sites, (ii) decrease in DNA end resection or formation of ssDNA, and (iii) decrease in ATR/Chk1 phosphorylation.