ZAP-70 is constitutively associated with tyrosine-phosphorylated TCR zeta in murine thymocytes and lymph node T cells

Immunity. 1994 Nov;1(8):675-85. doi: 10.1016/1074-7613(94)90038-8.


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

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Antibodies, Monoclonal / immunology
  • Antibodies, Monoclonal / pharmacology
  • Antigens, Differentiation, T-Lymphocyte / biosynthesis
  • Antigens, Differentiation, T-Lymphocyte / metabolism
  • Electrophoresis, Polyacrylamide Gel
  • Histocompatibility Antigens Class II / metabolism
  • Kinetics
  • Lymph Nodes / cytology*
  • Lymphocyte Activation
  • Mice
  • Mice, Inbred C57BL
  • Phosphorylation
  • Precipitin Tests
  • Protein-Tyrosine Kinases / metabolism*
  • Receptors, Antigen, T-Cell, gamma-delta / metabolism*
  • T-Lymphocytes / metabolism*
  • Thymus Gland / cytology*
  • Time Factors
  • Tyrosine / metabolism
  • ZAP-70 Protein-Tyrosine Kinase


  • Antibodies, Monoclonal
  • Antigens, Differentiation, T-Lymphocyte
  • Histocompatibility Antigens Class II
  • Receptors, Antigen, T-Cell, gamma-delta
  • Tyrosine
  • Protein-Tyrosine Kinases
  • ZAP-70 Protein-Tyrosine Kinase
  • Zap70 protein, mouse