Description
Nuclear factor kappa B (NF-?B) is a ubiquitous transcription factor and an essential mediator of gene expression during activation of immune and inflammatory responses. NF-?B mediates the expression of a great variety of genes in response to extracellular stimuli including IL-1, TNF? and LPS. A serine/threonine protein kinase associated with IL-1 receptor (IRAK) and its homologue mouse pelle-like protein kinase (mPLK) were identified recently (1,2). IRAK is associated with the IL-1 receptor subunits IL-1RI and IL-1RAcP after IL-1 binding and serves as a signaling molecule to mediate IL-1 response (3). IRAK mediates a signaling cascade leading to NF-?B activation by members in IL-1 family including IL-1 and a novel cytokine IL-18 (also termed IGIF) (1,4)