Ku70, known by several synonyms including X-ray repair cross-complementing, 5'-deoxyribose-5-phosphate lyase Ku70 protein 6, 70 kDa subunit of Ku antigen, XRCC6, and G22P1, is a 70 kDa protein that was shown to be involved in multiple cellular pathways, mainly involving DNA repair and recombination (2).
RAD51 is a recombinase protein encoded by RAD51 gene in humans. Human RAD51 family members are highly similar to bacterial RecA and yeast Rad51, both biochemically and structurally. It is a 339-amino acid protein that plays an important role in homologous recombination (HR) of DNA during double-strand break (DSB) repair.
Originally identified as autoantigens from a Scleroderma Polymyositis Syndrome patient (1), the Ku protein family consists of nuclear proteins found in eukaryotes. Autoantibodies to both Ku subunits were subsequently found in other autoimmune diseases such as Systemic Lupus Erythematosus.
Ku70 is a 70 kDa protein that was shown to be involved in multiple cellular pathways, mainly involving DNA repair and recombination. Among these are the non-homologus end repairs of DNA double strand breaks. Ku70 was first identified as an autoantigen in the serum of patients with Scleroderma Ploymyosistosis Syndrome (1).