Abstract
Although adaptor ADAP (FYB) and its binding to SLP-76 has been implicated in TcR-induced "inside-out" signaling for LFA-1 activation in T cells, little is known regarding its role in LFA-1-mediated "outside-in" signaling. In this study, we demonstrate that ADAP and SLP-76-ADAP binding are coupled to LFA-1 costimulation of IL-2 production, F-actin clustering, cell polarization, and T cell motility. LFA-1 enhancement of anti-CD3-induced IL-2 production was completely dependent on SLP-76-ADAP binding. Further, anti-CD3 was found to require CD11a ligation by antibody or ICAM1 to cause T cell polarization. ADAP augmented this polarization induced by anti-CD3/CD11a, but not by anti-CD3 alone. ADAP expression with LFA-1 ligation alone was sufficient to polarize T cells directly and to increase T cell motility whereas the loss of ADAP in ADAP-/- primary T cells reduced motility. A mutant lacking SLP-76-binding sites (M12) blocked LFA-1 costimulation of IL-2 production, polarization, and motility. LFA-1-ADAP polarization was also dependent on src kinases, Rho GTPases, phospholipase C, and phosphoinositol 3-kinase. Our findings provide evidence of an obligatory role for the SLP-76-ADAP module in LFA-1-mediated costimulation in T cells.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Actins / metabolism
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Adaptor Proteins, Signal Transducing / genetics
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Adaptor Proteins, Signal Transducing / metabolism*
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Animals
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Antibodies / pharmacology
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Binding Sites
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CD3 Complex / immunology
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Cell Line
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Cell Movement / drug effects
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Cell Polarity / drug effects
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Cells, Cultured
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Chromones / pharmacology
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Enzyme Inhibitors / pharmacology
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Green Fluorescent Proteins / genetics
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Green Fluorescent Proteins / metabolism
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Intercellular Adhesion Molecule-1 / pharmacology
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Interleukin-2 / metabolism
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Lymphocyte Function-Associated Antigen-1 / metabolism
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Mice
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Morpholines / pharmacology
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Mutation
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Phosphatidylinositol 3-Kinases / metabolism
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Phosphoinositide-3 Kinase Inhibitors
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Phosphoproteins / genetics
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Phosphoproteins / metabolism*
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Pyrimidines / pharmacology
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Signal Transduction / drug effects
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T-Lymphocytes / cytology
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T-Lymphocytes / drug effects
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T-Lymphocytes / metabolism
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rho GTP-Binding Proteins / antagonists & inhibitors
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rho GTP-Binding Proteins / metabolism
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src-Family Kinases / antagonists & inhibitors
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src-Family Kinases / metabolism
Substances
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AG 1879
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Actins
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Adaptor Proteins, Signal Transducing
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Antibodies
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CD3 Complex
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Chromones
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Enzyme Inhibitors
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Fyb protein, mouse
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Interleukin-2
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Lymphocyte Function-Associated Antigen-1
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Morpholines
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Phosphoinositide-3 Kinase Inhibitors
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Phosphoproteins
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Pyrimidines
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SLP-76 signal Transducing adaptor proteins
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Intercellular Adhesion Molecule-1
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Green Fluorescent Proteins
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2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one
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src-Family Kinases
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rho GTP-Binding Proteins