Abstract
The transcription factor NF-kappa B controls the induction of numerous cytokine promoters during the activation of T lymphocytes. Inhibition of T cell activation by the immunosuppressants cyclosporin A (CsA) and FK506 exerts a suppressive effect on the induction of these NF-kappa B-controlled cytokine promoters. We show for human Jurkat T leukemia cells, as well as human and mouse primary T lymphocytes, that this inhibitory effect is accompanied by an impaired nuclear translocation of the Rel proteins c-Rel, RelA/p65 and NF-kappa B1/p50, whereas the nuclear appearance of RelB remains unaffected. CsA does not interfere with the synthesis of Rel proteins, but prevents the inducible degradation of cytosolic NF-kappa B inhibitors I kappa B alpha and I kappa B beta upon T cell activation. CsA neither inhibits the processing of the NF-kappa B1 precursor p105 to p50, nor does it "stabilize" the C-terminal portion of p105, I kappa B gamma, which is degraded during p105 processing to mature p50. These results indicate that CsA interferes with a specific event in the signal-induced degradation of I kappa B alpha and I kappa B beta, but does not affect the processing of NF-kappa B1/p105 to p50.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Biological Transport / genetics
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Biological Transport / immunology
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Cell Nucleus / genetics
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Cell Nucleus / immunology
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Cyclosporine / pharmacology*
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Cysteine Endopeptidases / drug effects
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Cysteine Endopeptidases / metabolism
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Dose-Response Relationship, Immunologic
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Humans
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Jurkat Cells
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Lymphocyte Activation / drug effects
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Mice
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Mice, Inbred BALB C
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Multienzyme Complexes / drug effects
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Multienzyme Complexes / metabolism
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NF-kappa B / antagonists & inhibitors*
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NF-kappa B / drug effects*
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NF-kappa B / metabolism
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NF-kappa B p50 Subunit
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Proteasome Endopeptidase Complex
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Protein Precursors / drug effects*
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Protein Precursors / metabolism
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Protein Processing, Post-Translational / drug effects*
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Proto-Oncogene Proteins / biosynthesis*
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Proto-Oncogene Proteins / drug effects*
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Proto-Oncogene Proteins / metabolism
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T-Lymphocytes / drug effects*
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T-Lymphocytes / immunology
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T-Lymphocytes / metabolism
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Tacrolimus / pharmacology
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Transcription Factor RelB
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Transcription Factors*
Substances
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Multienzyme Complexes
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NF-kappa B
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NF-kappa B p50 Subunit
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Protein Precursors
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Proto-Oncogene Proteins
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RELB protein, human
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Relb protein, mouse
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Transcription Factors
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Transcription Factor RelB
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Cyclosporine
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Cysteine Endopeptidases
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Proteasome Endopeptidase Complex
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Tacrolimus