The p50 subunit of NF-kappa B associates with the NF-IL6 transcription factor.
The NF-kappa B-p50 polypeptide, a member of the Rel family of transcription factors, was produced as a fusion protein containing amino-terminal peptide additions that facilitate purification and detection with a monoclonal antibody and specific radiolabeling by phosphorylation in vitro. The 32P-labeled NK-kappa B-p50 fusion polypeptide was used as the probe in Western blotting experiments and in screenings of a bacteriophage expression library to isolate cDNAs encoding interacting protein domains. As expected, cDNAs encoding proteins of the Rel family were identified. Surprisingly, the 32P-labeled NF-kappa B protein also specifically bound to proteins encoded by cDNAs for the human NF-IL6 transcription factor. The NF-kappa B-p50 and NF-IL6 proteins directly interact, and the Rel homology domain and leucine-zipper motif, respectively, are important for this interaction. Since induction of the NF-kappa B and NF-IL6 factors are important events in immune and acute-phase responses, this interaction could permit coregulation of genes.
LeClair
K P
KP
Center for Cancer Research, Massachusetts Institute of Technology, Cambridge 02139.
Blanar
M A
MA
Sharp
P A
PA
D000595:Amino Acid Sequence; D015153:Blotting, Western; D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins / Q000378:metabolism*; D006801:Humans; D016350:Leucine Zippers; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D008970:Molecular Weight; D016328:NF-kappa B / Q000737:chemistry / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism*; D011233:Precipitin Tests; D011485:Protein Binding; D011994:Recombinant Proteins / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism*
D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins; D046911:Macromolecular Substances; D016328:NF-kappa B; D009687:Nuclear Proteins; D011994:Recombinant Proteins; D014157:Transcription Factors