Puneet Varma (Editor)


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Species  Human
Entrez  2547
Human  Mouse
Ensembl  ENSG00000196419
Ku70 XRCC6 Xray repair complementing defective repair in Chinese

Aliases  XRCC6, X-ray repair complementing defective repair in Chinese hamster cells 6, CTC75, CTCBF, G22P1, KU70, ML8, TLAA, X-ray repair cross complementing 6
External IDs  MGI: 95606 HomoloGene: 37483 GeneCards: XRCC6

Ku70 is a protein that, in humans, is encoded by the XRCC6 gene.



Ku70 Dynamic assembly of endjoining complexes requires interaction

Together, Ku70 and Ku80 make up the Ku heterodimer, which binds to DNA double-strand break ends and is required for the non-homologous end joining (NHEJ) pathway of DNA repair. It is also required for V(D)J recombination, which utilizes the NHEJ pathway to promote antigen diversity in the mammalian immune system.

Ku70 Purification of the Ku70Ku80 dimer A Schematic Figure 1 of 5

In addition to its role in NHEJ, Ku is also required for telomere length maintenance and subtelomeric gene silencing.

Ku was originally identified when patients with systemic lupus erythematosus were found to have high levels of autoantibodies to the protein.


Ku70 httpsuploadwikimediaorgwikipediacommonsthu

Mouse embryonic stem cells with homozygous Ku70 mutations, that is Ku70−/− cells, have markedly increased sensitivity to ionizing radiation compared to heterozygous Ku70+/− or wild-type Ku70+/+ embryonic stem cells. Mutant mice deficient in Ku70 exhibit early aging. Using several specific criteria of aging, the mutant mice were found to display the same aging signs as control mice, but at a considerably earlier chronological age. These results suggest that reduced ability to repair DNA double-strand breaks causes early aging, and that the wild-type Ku70 gene plays an important role in longevity assurance. (Also see DNA damage theory of aging.)


Ku70 has been referred to by several names including:

Ku70 Regulation of the proapoptotic factor Bax by Ku70dependent

  • Lupus Ku autoantigen protein p70
  • ATP-dependent DNA helicase 2 subunit 1
  • X-ray repair complementing defective repair in Chinese hamster cells 6
  • X-ray repair cross-complementing 6 (XRCC6)
  • Interactions

    Ku70 has been shown to interact with:

    Ku70 AntiKu70 antibody S5C11 ab3108 Abcam

    Ku70 Interaction of a Cyclin E Fragment with Ku70 Regulates BaxMediated


    Ku70 Wikipedia