Global γH2AX phosphorylation in Drosophila is reversed by the phosphatase Mts

The phosphorylation of the histone variant H2AX to form γH2AX is an early and critical histone modification during the DNA damage response. This phosphorylation has proven to be a highly specific molecular marker for tracking the initiation and resolution of DNA damage. In this study, we investigate the roles of three phosphatases in removing the 'γ' phospho-epitope from H2AX in <i>Drosophila</i> Kc167 cells. We found that the bulk of the X-ray-induced γH2AX signal is erased by the PP2A-type phosphatase MTS (microtubule star).