Figure 1.

A schematic of the γH2AX–pATM interaction network. In the presence of a DSB (a), pATM molecules are recruited to the DSB site at rate k₂, dissociate at rate k₄ and are further recruited by γH2AX at rate k₃. H2AX gets phosphorylated and γH2AX dephosphorylated at rates k₅ and k₆, respectively. In the absence of a DSB (b), a stable steady-state exists in which the concentrations of pATM and γH2AX are zero.