Ku80

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.

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.