Nuclear factor kappa B (NFkB) is a ubiquitous transcription factor and an essential mediator of gene expression during activation of immune and inflammatory responses. NFkB mediates the expression of a great variety of genes in response to extracellular stimuli including IL1, TNF alpha, and bacterial product LPS. NFkB is associated with IkB proteins in the cell cytoplasm, which inhibit NFkB activity. IKK is a serine protein kinase, and the IKK complex contains alpha and beta subunits (IKK alpha and IKK beta). IKK alpha and IKK beta interact with each other and both are essential for NFkB activation. IKK alpha specifically phosphorylates IkBa. IKKa is expressed in variety of human tissues.