Translocation of the interleukin-1 receptor-associated kinase-1 (IRAK-1) into the nucleus

Interleukin-1 (IL-1) signal transduction involves the recruitment of the IL-1 receptor-associated kinase-1 (IRAK-1). Subsequent signaling finally leads to nuclear translocation of NF kappa E. We here show that the association and autophosphorylation of IRAK-1 was already detectable 30 s after IL-1 stimulation of ECV 304 cells. Significant levels of IRAK-1 accumulated in the nucleus 30 min after IL-1 stimulation shown by Western blot analysis and confocal laser scanning microscopy. Nuclear transfer of IRAK-1 upon IL-1 stimulation Ras confirmed in the murine T cell line EL-4, This characterizes nuclear localization of IRAK-1 as a possibly essential event in the IL-1 signaling cascade. (C) 2000 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved.