Figure 6. Schematic depiction of the effect of CCAR2 on DNA end resection.

CtIP and CCAR2 interact constitutively. Upon the appearance of DSBs, they are both recruited (ii), but soon only one of them is left remaining at the breaks (iii and iv). DSB repaired by NHEJ maintains CCAR2 in an ATM-dependent manner, facilitating repair (iii). In contrast, DSBs that require DNA end resection maintain only CtIP at the break, and, indeed, CCAR2 is completely excluded from the region in a CtIP and/or DNA end resection manner (iv). This allows resection to progress until it covers the CCAR2-free region (v).