Fig. 7: Schematic diagram showing the role of RRM1 in regulating DSB repair.

RRM1 interacts with USP11 in the cytoplasm. IR induces the entry of RRM1 into the nucleus while promoting the entry of USP11. USP11 in the nucleus can exert a deubiquitination function on E2F1 and inhibit the ubiquitination degradation of E2F1. High levels of E2F1 promote the transcription of RAD51AP1, thereby enhancing HR and the radiation sensitivity of tumor cells.