X-ray repair cross-complementing protein 6 (XRCC6)

X-ray repair cross-complementing protein 6 (XRCC6), also known as Ku70, is a critical component of the non-homologous end joining (NHEJ) pathway for DNA double-strand break repair. It forms a heterodimer with Ku80 (XRCC5), binding to DNA ends with high affinity and shielding them from nucleolytic degradation, while recruiting additional repair factors including DNA-dependent protein kinase catalytic subunit (DNA-PKcs), XRCC4, and Ligase IV[1][3][4][6]. Ku70 is also essential for V(D)J recombination in lymphocyte development, telomere maintenance, and modulation of apoptosis via interaction with proteins such as Bax and p53. Beyond nuclear functions, Ku70 acts as a cytosolic DNA sensor, activating innate immune responses, and serves as a cell-surface receptor in bacterial internalization. Mutation or altered expression of XRCC6 is implicated in cancer, neurodegeneration, and immune disorders. As a therapeutic target, its primary relevance is for modulating DNA repair in cancer therapy and as a marker for disease susceptibility and treatment response[3][5].

Other names

Ku705'-dRP lyase Ku70DNA repair protein XRCC6ATP-dependent DNA helicase 2 subunit 1Lupus Ku autoantigen protein p70Thyroid-lupus autoantigenCTC75CTCBFG22P1ML8TLAA70 kDa subunit of Ku antigen5'-deoxyribose-5-phosphate lyase Ku70

Inhibition of non-homologous end joining by targeting components of DNA-PK (including Ku70/Ku80/DNA-PKcs complex) reduces DNA repair capacity and sensitizes cells to DNA damage Ku70 may be targeted to sensitize tumor cells to radiation or DNA-damaging agents Modulation of immune sensing pathways (cytosolic DNA sensing via Ku70)