Abstract
cAMP inhibits T cell activation by acting as an antagonist for selective kinases and transcriptional factors. We have recently demonstrated that cAMP inhibited c-Jun N-terminal kinase (JNK) but left the mitogen-activated protein (MAP) kinase cascade almost unaffected in T lymphocytes. In accordance with recent reports, we also observed a selective suppression of nuclear factor NF-kappaB activation by cAMP. The possible link between the JNK cascade and NF-kappaB activation was demonstrated by the fact that the active form of MAP kinase kinase kinase (deltaMEKK), a constitutive activator of JNK, induced NF-kappaB but not AP-1, Oct, and NF-AT in T cells. In contrast, the induction of MAP kinase kinase (MEK)-MAP kinase did not stimulate NF-kappaB activity. The specific activation of NF-kappaB by a single MEKK-JNK cascade was thus unusual, given that the activation of other transcriptional elements in T cells requires at least two signal pathways. This was further confirmed by the fact that cAMP inhibition of NF-kappaB activation was reversed by overexpression of deltaMEKK.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Cyclic AMP / antagonists & inhibitors*
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DNA-Binding Proteins / antagonists & inhibitors
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Fetal Proteins / metabolism
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Gene Expression Regulation / drug effects
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Host Cell Factor C1
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JNK Mitogen-Activated Protein Kinases*
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MAP Kinase Kinase 4
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MAP Kinase Kinase Kinases
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Mice
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Mitogen-Activated Protein Kinase Kinases*
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NF-kappa B / antagonists & inhibitors*
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NFATC Transcription Factors
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Nuclear Proteins*
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Octamer Transcription Factor-1
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Protein Kinases / metabolism
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Protein Serine-Threonine Kinases / physiology*
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Proto-Oncogene Proteins / physiology
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Receptor Protein-Tyrosine Kinases / metabolism
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Receptor, EphA4
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Signal Transduction
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T-Lymphocytes / physiology*
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Transcription Factor AP-1 / antagonists & inhibitors
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Transcription Factor RelB
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Transcription Factors / antagonists & inhibitors
Substances
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DNA-Binding Proteins
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Fetal Proteins
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Hcfc1 protein, mouse
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Host Cell Factor C1
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NF-kappa B
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NFATC Transcription Factors
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Nuclear Proteins
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Octamer Transcription Factor-1
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Pou2f1 protein, mouse
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Proto-Oncogene Proteins
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Relb protein, mouse
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Transcription Factor AP-1
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Transcription Factors
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Transcription Factor RelB
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Cyclic AMP
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Protein Kinases
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Receptor Protein-Tyrosine Kinases
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Receptor, EphA4
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Protein Serine-Threonine Kinases
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JNK Mitogen-Activated Protein Kinases
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MAP Kinase Kinase Kinases
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MAP Kinase Kinase 4
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Mitogen-Activated Protein Kinase Kinases