[3] Ku is thought to function as a molecular scaffold to which other proteins involved in NHEJ can bind, orienting the double-strand break for ligation.

[5] The C-terminal arm is an alpha helical region which embraces the central beta-barrel domain of the opposite subunit.

[1] In some cases a fourth domain is present at the C-terminus, which binds to DNA-dependent protein kinase catalytic subunit.

These mice exhibit chromosomal instability, indicating that NHEJ is important for genome maintenance.

In rice, suppression of either protein has been shown to promote homologous recombination (HR)[13] This effect was exploited to improve gene targeting (GT) efficiency in Arabidopsis thaliana.

In the study, the frequency of HR-based GT using a zinc-finger nuclease (ZFN) was increased up to sixteen times in ku70 mutants[14] This result has promising implications for genome editing across eukaryotes as DSB repair mechanisms are highly conserved.

A substantial difference is that in plants, Ku is also involved in maintaining an alternate telomere morphology characterized by blunt-ends or short (≤ 3-nt) 3’ overhangs.

[18] Bacterial and archaeal Ku proteins are unlike their eukaryotic counterparts in that they only have the central beta-barrel domain.