Abstract
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.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Animals
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Antibodies
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B-Cell Lymphoma 3 Protein
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Base Sequence
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Cell Nucleus / metabolism*
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Cells, Cultured
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Cloning, Molecular
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism
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Macromolecular Substances
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Molecular Sequence Data
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Molecular Weight
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NF-kappa B / biosynthesis
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NF-kappa B / genetics*
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NF-kappa B / metabolism
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Oligodeoxyribonucleotides
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Peptides / chemical synthesis
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Peptides / immunology
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Protein Precursors / biosynthesis
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Protein Precursors / genetics*
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Protein Precursors / metabolism
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Proto-Oncogene Proteins / biosynthesis
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Proto-Oncogene Proteins / genetics*
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Proto-Oncogene Proteins / metabolism
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Proto-Oncogenes*
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Recombinant Proteins / metabolism
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Restriction Mapping
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Transcription Factors
Substances
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Antibodies
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B-Cell Lymphoma 3 Protein
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DNA-Binding Proteins
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Macromolecular Substances
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NF-kappa B
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Oligodeoxyribonucleotides
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Peptides
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Protein Precursors
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Proto-Oncogene Proteins
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Recombinant Proteins
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Transcription Factors