Direct association of pp40/I kappa B beta with rel/NF-kappa B transcription factors: role of ankyrin repeats in the inhibition of DNA binding activity

Proc Natl Acad Sci U S A. 1992 May 15;89(10):4333-7. doi: 10.1073/pnas.89.10.4333.


To understand the mechanism by which pp40/I kappa B beta inhibits DNA binding activity of the rel/NF-kappa B family of transcription factors, we have investigated the role of ankyrin repeats on the biological function of pp40 by deleting or mutating conserved residues. We show that (i) ankyrin repeats alone are not sufficient to manifest biological activity but require the C-terminal region of the pp40 protein; (ii) four out of the five ankyrin repeats are essential for inhibiting the DNA binding activity; (iii) pp40 mutants that do not inhibit DNA binding of rel protein also do not associate with rel; (iv) although pp40 can associate with the p65 and p50 subunits of NF-kappa B, pp40 inhibits the DNA binding activity of only the p50-p65 heterodimer and the p65 homodimer; and (v) pp40 inhibits the transcription of genes linked to kappa B site; however, mutants that do not affect DNA binding have no effect. We propose that the ankyrin repeats and the C-terminal region of pp40 form a structure that associates with the rel homology domain to inhibit DNA binding activity.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Ankyrins
  • Base Sequence
  • Blood Proteins / genetics*
  • Blood Proteins / metabolism
  • Cell Line
  • DNA / metabolism*
  • Kinetics
  • Membrane Proteins / genetics*
  • Membrane Proteins / metabolism
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed
  • NF-kappa B / genetics
  • NF-kappa B / metabolism*
  • Oligodeoxyribonucleotides
  • Oncogene Proteins v-rel
  • Phosphoproteins / metabolism*
  • Protein Biosynthesis
  • Proto-Oncogene Proteins / genetics
  • Proto-Oncogene Proteins / metabolism*
  • Proto-Oncogene Proteins c-rel
  • Repetitive Sequences, Nucleic Acid
  • Restriction Mapping
  • Retroviridae Proteins, Oncogenic / genetics
  • Retroviridae Proteins, Oncogenic / metabolism*
  • Transcription Factor RelB
  • Transcription Factors / metabolism*
  • Transfection


  • Ankyrins
  • Blood Proteins
  • Membrane Proteins
  • NF-kappa B
  • Oligodeoxyribonucleotides
  • Oncogene Proteins v-rel
  • Phosphoproteins
  • Proto-Oncogene Proteins
  • Proto-Oncogene Proteins c-rel
  • Retroviridae Proteins, Oncogenic
  • Transcription Factors
  • Transcription Factor RelB
  • DNA