Two very recent publications, by Suzuki et al. and Li et al., describe the cloning, characterization, and the effects of knockout
mice deficient in interleukin-1-associated receptor kinase-4 (IRAK-4), the newest member of the IRAK family. IRAK-4 requires
its kinase activity to activate NF-κB, and IRAK-4 also activates MAP kinases. Wietek and O’Neill discuss the data indicating
that IRAK-4 lies upstream of and activates IRAK-1, and that IRAK-4 is essential for innate immunity.