USP11 is a negative regulator to γh2AX ubiquitylation by RNF8/RNF168

Abstract

Ubiquitin modification at double strand breaks (DSB) sites is an essential regulator of signaling and repair. γH2AX extends from DSB sites and provides a platform for subsequent recruitment and amplification of DNA repair proteins and signaling factors. Here, we found that RNF8/RNF168 ubiquitylates γH2AX. We identified that USP11 is a unique deubiquitylation enzyme forγH2AX. USP11 deubiquitylatesγH2AXboth in vivo and in vitro but not the canonical (ub)-K119-H2A and (ub)- K120-H2B in vitro, and USP11 ablation enhances the levels of γH2AX ubiquitylation. We also found that USP11 interacts With γH2AX both in vivo and in vitro.Wefound that 53BP1 and ubiquitin-conjugated proteins are misregulated to be retained longer and stronger at DSB sites after knockdown of USP11.We further found that cells are hypersensitive to γ-irradiation after ablation of USP11. Together, our findings elucidate deeply and extensively the mechanism of RNF8/RNF168 and USP11 to maintain the proper status of ubiquitylation γH2AX to repair DSB.