Fig. 8. Schematic illustration of the localization signals of NIK. From the results obtained with various mutants of YFP-NIK, a scheme of the targeting domains is depicted, showing the nucleolar localization sequence (NoLS, amino acids RKKR at position 143-146), the nuclear localization sequence (NLS, amino acids KKK at 146-149), and the functional nuclear export sequence (NES, amino acids 795-805).