Abstract
The ufmylation ligase-UFL1 promotes ATM activation by monoufmylating H4 at K31 in a positive-feedback loop after double-strand breaks (DSB) occur, whereas UFM1 Specific Peptidase 2 (UfSP2) suppresses ATM activation, but the mechanism of recruitment of UfSP2 to the DSB finetuning DNA damage response is still not clear. Here, we report that UfSP2 foci formation is delayed compared to UFL1 foci formation following the radiation insult. Mechanistically, UfSP2 binds to the MRN complex in absence of DSB. Irradiation-induced phosphorylation of UfSP2 by ATM leads to the dissociation of UfSP2 from the MRN complex. This phosphorylation can be removed by the phosphatase WIP1, thereby UfSP2 is recruited to the DSBs, deufmylating H4 and suppressing ATM activation. In summary, we identify a mechanism of delicately negative modulation of ATM activation by UfSP2 and rewires ATM activation pathways.