Ku70

The nuclear factor kappa B (NFkB) is a ubiquitous transcription factor essential for the activation of immune and inflammatory responses. NFkB activity is inhibited when it is associated with IkB proteins in the cell cytoplasm. IkB proteins are phosphorylated by the IkB kinase complex. The IKK serine protein kinase consists of alpha and beta subunits (IKK alpha and IKK beta). These subunits interact with each other and together, are essential for NFkB activation. IKK alpha is expressed in variety of human tissues.

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).

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).