Abstract
Studies with T cell lines and clones have shown that engagement of the TCR results in the tyrosine phosphorylation of the TCR subunits. This leads to the recruitment of the ZAP-70 protein tyrosine kinase, an interaction involving the two SH2-domains of ZAP-70 with tyrosine-phosphorylated zeta and CD3. However, as previously described, murine thymocytes and lymph node T cells express a constitutively tyrosine-phosphorylated zeta subunit in the basal state. Here, we show that a fraction of ZAP-70 molecules are constitutively associated with tyrosine-phosphorylated zeta. TCR ligation promotes a large increase in the tyrosine phosphorylation of ZAP-70 as well as other TCR subunits. Genetic studies reveal that the constitutive ZAP-70 association with tyrosine-phosphorylated zeta does not absolutely require either TCR or coreceptor interactions with MHC molecules.
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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Animals
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Antibodies, Monoclonal / immunology
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Antibodies, Monoclonal / pharmacology
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Antigens, Differentiation, T-Lymphocyte / biosynthesis
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Antigens, Differentiation, T-Lymphocyte / metabolism
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Electrophoresis, Polyacrylamide Gel
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Histocompatibility Antigens Class II / metabolism
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Kinetics
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Lymph Nodes / cytology*
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Lymphocyte Activation
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Mice
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Mice, Inbred C57BL
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Phosphorylation
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Precipitin Tests
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Protein-Tyrosine Kinases / metabolism*
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Receptors, Antigen, T-Cell, gamma-delta / metabolism*
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T-Lymphocytes / metabolism*
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Thymus Gland / cytology*
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Time Factors
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Tyrosine / metabolism
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ZAP-70 Protein-Tyrosine Kinase
Substances
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Antibodies, Monoclonal
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Antigens, Differentiation, T-Lymphocyte
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Histocompatibility Antigens Class II
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Receptors, Antigen, T-Cell, gamma-delta
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Tyrosine
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Protein-Tyrosine Kinases
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ZAP-70 Protein-Tyrosine Kinase
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Zap70 protein, mouse