PIAS4 SUMOylates HERC2 with SUMO1 at DNA DSBs

PIAS4 SUMOylates HERC2 at an unknown lysine residue with SUMO1. ATM activity is needed for PIAS4-mediated HERC2 SUMOylation and it is therefore plausible that the ATM-mediated phosphorylation of HERC2 precedes HERC2 SUMOylation. Once SUMOylated, the ZZ domain of HERC2 interacts with the attached SUMO1 group, probably leading to a conformational change that allows binding of phosphorylated HERC2 to RNF8 (Bekker-Jensen et al. 2010, Danielsen et al. 2012).

PIAS4在未知赖氨酸残基处通过SUMO1对HERC2进行SUMO化修饰。ATM活性对于PIAS4介导的HERC2 SUMO化修饰至关重要，因此，ATM介导的HERC2磷酸化可能先于HERC2 SUMO化发生。一旦SUMO化修饰完成，HERC2的ZZ结构域将与附着的SUMO1分子相互作用，可能引发构象变化，从而允许磷酸化的HERC2与RNF8（Bekker-Jensen等人，2010年，Danielsen等人，2012年）结合。