Abstract
We previously identified a putative signal transducing adaptor molecule, named STAM, that contains an Src homology 3 (SH3) domain and immunoreceptor tyrosine-based activation motif (ITAM). In this report, we demonstrate the functional significance of STAM in cytokine-mediated signal transduction. STAM is associated with Jak3 and Jak2 tyrosine kinases via its ITAM region and phosphorylated by Jak3 and Jak2 upon stimulation with IL-2 and GM-CSF, respectively. An SH3 deletion mutant of STAM confers a dominant-negative effect on DNA synthesis mediated by IL-2 and GM-CSF. Furthermore, the wild-type STAM, but not STAM mutants deleted of SH3 and ITAM, significantly enhances c-myc induction mediated by IL-2 and GM-CSF. These results strongly implicate STAM in the signaling pathways for cell growth and c-myc induction immediately downstream of the Jaks associated with the cytokine receptors.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adaptor Proteins, Signal Transducing*
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Animals
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Cell Division / genetics
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Cell Division / immunology
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DNA / biosynthesis
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Endosomal Sorting Complexes Required for Transport
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Gene Expression Regulation / drug effects
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Gene Expression Regulation / immunology*
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Genes, myc / drug effects
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Genes, myc / immunology*
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Granulocyte-Macrophage Colony-Stimulating Factor / pharmacology
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Humans
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Interleukin-2 / pharmacology
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Janus Kinase 2
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Janus Kinase 3
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Mice
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Mutation
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Phosphoproteins / metabolism*
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Phosphorylation
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Protein-Tyrosine Kinases / genetics
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Protein-Tyrosine Kinases / metabolism*
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Protein-Tyrosine Kinases / physiology
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Proto-Oncogene Proteins*
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Receptors, Interleukin-2 / genetics
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Signal Transduction / genetics
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Signal Transduction / immunology*
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Transfection
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Tumor Cells, Cultured
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Tyrosine / metabolism
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src Homology Domains / genetics
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src Homology Domains / immunology*
Substances
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Adaptor Proteins, Signal Transducing
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Endosomal Sorting Complexes Required for Transport
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Interleukin-2
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Phosphoproteins
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Proto-Oncogene Proteins
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Receptors, Interleukin-2
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STAM protein, human
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Stam protein, mouse
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Tyrosine
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Granulocyte-Macrophage Colony-Stimulating Factor
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DNA
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Protein-Tyrosine Kinases
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JAK2 protein, human
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JAK3 protein, human
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Jak2 protein, mouse
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Jak3 protein, mouse
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Janus Kinase 2
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Janus Kinase 3