Figure 7.

Model of Ku-dependent and independent DSB repair. In the presence of Ku, DSB repair is mainly executed by accurate NHEJ. A minor fraction is normally also repaired by HR or SSA (17). In the absence of Ku, repair is shuttled to all three other pathways which likely share a common initial end resection step. The lack of Ku binding leaves space for key proteins to bind such as PARP1, Rad51 or Rad52, respectively. The majority of DSBs are still repaired by end-joining, however by an alternative PARP1-dependent mode.