Asp-451 in ANK1 of IκBζ and the corresponding residue of IκBNS and Bcl-3 are involved in interaction with NF-κB p52.
A, the role for IκBζ Asp-451, IκBNS Asp-60, and Bcl-3 Asp-127 in interaction with NF-κB p50 in vitro. GST-fused IκBζ, IκBNS, and Bcl-3 with or without the indicated amino acid substitution were incubated with His-p52-(1–341), and pulled down with glutathione-Sepharose-4B beads, followed by SDS-PAGE analysis with CBB staining. MW, molecular weight. B–D, the role of IκBζ Asp-451, IκBNS Asp-60, and Bcl-3 Asp-127 in interaction with NF-κB p50 in vivo. FLAG-tagged IκBζ (B), IκBNS (C), or Bcl-3 (D) with or without the indicated amino acid substitution was co-expressed with HA-p52 in HEK293T cells, and proteins in the cell lysate were immunoprecipitated (IP) with the anti-FLAG antibody, followed by immunoblot analysis with the indicated antibody (Blot). Positions for marker proteins are indicated in kilodaltons.