Figure 2.

Schematic representation of protein domains in IκBα. The N-terminal SRD is the site of phosphorylation by IKK and subsequent ubiquitination by the SCF (β-TrCP) E3 ligase, six ankyrin repeat units make up the central ARD domain. The ankyrin repeat units in the protein crystal structure of IκBα in complex with NF-κB (pdb entry 1IKN) are shown as a cartoon representation. Indicated for the C-terminal PEST-like region are the CKII sites of phosphorylation. The diversity of binding sites, the great variability of κB-sites in the DNA motif and the existence of suppressive and inductive NF-κB dimers lead to a complexity and versatility of the downstream signaling network.