Figure 1.

Schematic diagram of NF-κB and IκB family members. (A) The proteins p100 and p105 are the precursors of p52 and p50; they lack transactivation domain (TAD), which bind to other proteins such as transcription factors coregulators. Black arrowheads are pointing to C terminal proteolytic cleavage sites originating p52 and p50. NF-κB family proteins contain sequences required for DNA binding, dimerization, and nuclear localization, called Rel Homology Domain (RHD). (B) Typical and Atypical members of the NF-κB inhibitors (IκB) family are characterized by the presence of Ankyrin Repeats (AR) and their ability to bind and sequester NF-κB dimers in the cytoplasm (typical members) or recruit them to specific gene promoters in the nucleus (atypical members). RHD, Rel homology domain; TAD, transactivation domain; GRR, glycine-rich region; AR, ankyrin repeats; PEST, proline-, glutamic acid-, serine threonine-rich sequence; NLS, Nuclear Localization Signal; NES, Nuclear Export Signal.