Fig. 1. Structural comparison between Cactus and IB. Schematic diagrams of Cactus and IB are shown with hatched yellow regions indicating the positions of the six complete ankyrin repeats in each protein. The position and sequence of the identified IKK target motif is shown above IB, as are the position of the two Cactus regulatory elements discussed in this study. The position of serine (red) and lysine (blue) residues located N-terminal to the first ankyrin repeat are shown. Lysine and serine residues present in other parts of the proteins are not shown.