Abstract
Phosphoinositide (PI) 3-kinase has been implicated in T cell receptor (TCR) signaling, either as a positive or a negative regulatory molecule. Here, we show that for normal mouse lymph node T cells, PI 3-kinase activity is required for interleukin-2 (IL-2) production following TCR-mediated activation. Furthermore, in normal T cells, inhibition of PI 3-kinase prevented activation of enzymes in the extracellular signal-regulated protein kinase (ERK) signaling pathway (MEK-1 and ERK-2). Overexpression of a dominant-negative mutant of PI 3-kinase and pharmacological inhibitors of PI 3-kinase prevented transcriptional activation of AP-1 and NF-AT, transcription factors regulated by ERK-2 and pivotal for IL-2 gene expression. Although a constitutively active form of Akt kinase, a downstream mediator of PI 3-kinase function, enhanced TCR-induced IL-2 gene transcription, it could not bypass the requirement for PI 3-kinase activity. Therefore, PI 3-kinase is likely to be involved in signaling for IL-2 production in at least two steps in the TCR-initiated signaling pathway.
MeSH terms
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Androstadienes / pharmacology
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Animals
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Chromones / pharmacology
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Enzyme Activation
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Female
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Interleukin-2 / biosynthesis*
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Lymph Nodes / cytology
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Lymph Nodes / immunology*
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Lymphocyte Activation
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MAP Kinase Kinase 1
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Male
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Mice
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Mice, Inbred C57BL
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Mitogen-Activated Protein Kinase 1 / metabolism
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Mitogen-Activated Protein Kinase Kinases*
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Mitogen-Activated Protein Kinases / metabolism
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Morpholines / pharmacology
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Mutation
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Phosphatidylinositol 3-Kinases / genetics
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Phosphatidylinositol 3-Kinases / metabolism*
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Phosphoinositide-3 Kinase Inhibitors
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Protein Serine-Threonine Kinases / metabolism
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Protein-Tyrosine Kinases / metabolism
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Proto-Oncogene Proteins / metabolism
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Proto-Oncogene Proteins c-akt
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Receptors, Antigen, T-Cell / metabolism*
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Signal Transduction
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T-Lymphocytes / immunology*
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Transcription, Genetic
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Wortmannin
Substances
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Androstadienes
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Chromones
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Interleukin-2
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Morpholines
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Phosphoinositide-3 Kinase Inhibitors
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Proto-Oncogene Proteins
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Receptors, Antigen, T-Cell
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2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one
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Protein-Tyrosine Kinases
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Protein Serine-Threonine Kinases
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Proto-Oncogene Proteins c-akt
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Mitogen-Activated Protein Kinase 1
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Mitogen-Activated Protein Kinases
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MAP Kinase Kinase 1
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Map2k1 protein, mouse
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Mitogen-Activated Protein Kinase Kinases
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Wortmannin