Abstract
T cell activation stimulates p56(lck), p59(fyn), ZAP-70, Vav-SLP-76 binding, and IL-2 transcription. Major questions concern the tyrosine-kinase and relevant site(s) needed for Vav-SLP-76 complex formation and its role in IL-2 production. Here, we show that of the three kinases, only ZAP-70 phosphorylates SLP-76 at specific sites that allow Vav SH2 domain binding. Therefore, while p56(lck) regulates proximal events, ZAP-70 acts downstream on targets such as SLP-76. We also show by in vitro and in vivo analysis that two SLP-76 pYESP motifs (Y113 and Y128) mediate binding, the first being more efficient. A third pYEPP motif (Y145) failed to bind. Finally, TCR zeta CD3 ligation of T cell hybridoma DC27.10 induces IL-2 production without detectable Vav-SLP-76 binding. Therefore, despite effects of Vav-SLP-76 on IL-2 expression, Vav-SLP-76 binding per se is not essential for IL-2 production in all T cells.
Publication types
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Adaptor Proteins, Signal Transducing
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Amino Acid Sequence
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Animals
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Cell Line
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Humans
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Interleukin-2 / biosynthesis*
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Interleukin-2 / metabolism*
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Jurkat Cells
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Membrane Proteins / immunology*
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Mice
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Molecular Sequence Data
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Oncogene Proteins / drug effects*
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Oncogene Proteins / metabolism*
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Phosphoproteins / drug effects*
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Phosphoproteins / metabolism*
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Protein Binding / drug effects
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Protein-Tyrosine Kinases / pharmacology*
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Proto-Oncogene Proteins c-vav
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Receptor-CD3 Complex, Antigen, T-Cell / immunology*
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Receptors, Antigen, T-Cell / immunology*
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T-Lymphocytes / drug effects
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T-Lymphocytes / metabolism
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ZAP-70 Protein-Tyrosine Kinase
Substances
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Adaptor Proteins, Signal Transducing
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Interleukin-2
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Membrane Proteins
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Oncogene Proteins
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Phosphoproteins
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Proto-Oncogene Proteins c-vav
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Receptor-CD3 Complex, Antigen, T-Cell
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Receptors, Antigen, T-Cell
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SLP-76 signal Transducing adaptor proteins
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VAV1 protein, human
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Vav1 protein, mouse
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antigen T cell receptor, zeta chain
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Protein-Tyrosine Kinases
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ZAP-70 Protein-Tyrosine Kinase
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ZAP70 protein, human
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Zap70 protein, mouse