Abstract
One of the earliest functional responses of T lymphocytes to extracellular signals that activate the Ag-specific CD3/TCR complex is a rapid, but reversible, increase in the functional activity of integrin adhesion receptors. Previous studies have implicated the tyrosine kinase zeta-associated protein of 70 kDa (ZAP-70) and the lipid kinase phosphatidylinositol 3-kinase, in the activation of beta(1) integrins by the CD3/TCR complex. In this report, we use human ZAP-70-deficient Jurkat T cells to demonstrate that the kinase activity of ZAP-70 is required for CD3/TCR-mediated increases in beta(1) integrin-mediated adhesion and activation of phosphatidylinositol 3-kinase. A tyrosine to phenylalanine substitution at position 315 in the interdomain B of ZAP-70 inhibits these responses, whereas a similar substitution at position 292 enhances these downstream signals. These mutations in the ZAP-70 interdomain B region also specifically affect CD3/TCR-mediated tyrosine phosphorylation of residues 171 and 191 in the cytoplasmic domain of the linker for activation of T cells (LAT) adapter protein. CD3/TCR signaling to beta(1) integrins is defective in LAT-deficient Jurkat T cells, and can be restored with expression of wild-type LAT. Mutant LAT constructs with tyrosine to phenylalanine substitutions at position 171 and/or position 191 do not restore CD3/TCR-mediated activation of beta(1) integrins in LAT-deficient T cells. Thus, these studies demonstrate that the interdomain B region of ZAP-70 regulates beta(1) integrin activation by the CD3/TCR via control of tyrosine phosphorylation of tyrosine residues 171 and 191 in the LAT cytoplasmic domain.
Publication types
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Research Support, Non-U.S. Gov't
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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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Adaptor Proteins, Vesicular Transport / physiology*
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Animals
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Carrier Proteins / genetics
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Carrier Proteins / metabolism
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Carrier Proteins / physiology*
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Cell Adhesion / genetics
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Cell Adhesion / immunology
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Clone Cells
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Cytoplasm / genetics
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Cytoplasm / immunology
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Enzyme Activation / genetics
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Enzyme Activation / immunology
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Fibronectins / metabolism
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Humans
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Integrin beta1 / metabolism*
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Integrin beta1 / physiology
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Jurkat Cells
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Membrane Proteins / genetics
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Membrane Proteins / metabolism
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Membrane Proteins / physiology*
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Mice
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Mice, Inbred C57BL
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Mutation
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Phosphatidylinositol 3-Kinases / metabolism
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Phospholipase C gamma
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Phosphoproteins / genetics
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Phosphoproteins / metabolism
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Phosphoproteins / physiology*
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Phosphorylation
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Protein Structure, Tertiary / genetics
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Protein-Tyrosine Kinases / deficiency
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Protein-Tyrosine Kinases / genetics
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Protein-Tyrosine Kinases / physiology*
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Receptor-CD3 Complex, Antigen, T-Cell / antagonists & inhibitors
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Receptor-CD3 Complex, Antigen, T-Cell / physiology*
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Signal Transduction / immunology
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T-Lymphocytes / enzymology
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T-Lymphocytes / immunology*
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T-Lymphocytes / metabolism
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Type C Phospholipases / physiology
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Tyrosine / metabolism
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Up-Regulation / immunology
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ZAP-70 Protein-Tyrosine Kinase
Substances
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Adaptor Proteins, Signal Transducing
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Adaptor Proteins, Vesicular Transport
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Carrier Proteins
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Fibronectins
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Integrin beta1
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LAT protein, human
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Lat protein, mouse
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Membrane Proteins
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Phosphoproteins
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Receptor-CD3 Complex, Antigen, T-Cell
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Tyrosine
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Phosphatidylinositol 3-Kinases
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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
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Type C Phospholipases
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Phospholipase C gamma