The NF-kappa B precursor p105 and the proto-oncogene product Bcl-3 are I kappa B molecules and control nuclear translocation of NF-kappa B.
We have examined the interaction of the NF-kappa B precursor p105 with NF-kappa B subunits. Similar to an I kappa B molecule, p105 associates in the cytoplasm with p50 or p65. Through this assembly, p105 efficiently blocks nuclear transfer of either subunit. Moreover, the p105 protein inhibits DNA binding of dimeric NF-kappa B subunits in a similar, but not identical, manner to its isolated C-terminal domain, which contains an ankyrin-like repeat domain (ARD). The proto-oncogene product Bcl-3 also controls nuclear translocation of p50, but not of p65. Hence, p50 can be retained in the cytoplasm via at least three distinct interactions: through direct interactions either with its own precursor, with Bcl-3 or indirectly through I kappa B alpha or -beta when attached to p65. We discuss a function of p105 as a cytoplasmic assembly unit for homo- and heteromeric NF-kappa B complexes and of Bcl-3 as an I kappa B with novel subunit specificity.
Naumann
M
M
Max-Planck-Institut für Molekulare Genetik, Otto-Warburg-Laboratorium, Berlin-Dahlem, Germany.
Wulczyn
F G
FG
Scheidereit
C
C
D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies; D000081242:B-Cell Lymphoma 3 Protein; D001483:Base Sequence; D002467:Cell Nucleus / Q000378:metabolism*; D002478:Cells, Cultured; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D008970:Molecular Weight; D016328:NF-kappa B / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D009838:Oligodeoxyribonucleotides; D010455:Peptides / Q000138:chemical synthesis / Q000276:immunology; D011498:Protein Precursors / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D011519:Proto-Oncogenes; D011994:Recombinant Proteins / Q000378:metabolism; D015183:Restriction Mapping; D014157:Transcription Factors
D000906:Antibodies; D000081242:B-Cell Lymphoma 3 Protein; D004268:DNA-Binding Proteins; D046911:Macromolecular Substances; D016328:NF-kappa B; D009838:Oligodeoxyribonucleotides; D010455:Peptides; D011498:Protein Precursors; D011518:Proto-Oncogene Proteins; D011994:Recombinant Proteins; D014157:Transcription Factors