Characterization of p59fyn-mediated signal transduction on T cell activation

Int Immunol. 1994 Aug;6(8):1245-55. doi: 10.1093/intimm/6.8.1245.


Protein tyrosine kinase p59fyn is associated with the TCR-CD3 complex and is suggested to play a role in T cell activation. To determine the molecular mechanism of p59fyn-mediated signal transduction in T cell activation, we established murine T cell hybridoma lines that expressed an elevated amount of wild-type or mutant fyns. Clones that expressed high levels of normal p59fyn and active p59fyn, encoded by wild-type and f-14 mutant fyn respectively, showed enhanced IL-2 production upon stimulation by anti-CD3 antibodies or natural antigen. On the other hand, clones that expressed kinase negative p59fyn and p59fyn with an SH2 (Src-homology 2) deletion encoded by t-1 mutant fyn showed little induction of IL-2 production upon stimulation. These data suggest that p59fyn is important in T cell signaling and that the SH2 sequence plays a critical role in the reaction. Induction of tyrosine phosphorylation of multiple proteins upon antigenic stimulation was augmented similarly in the cells that respectively expressed wild-type and f-14 mutant fyns at elevated levels. The proteins that became highly tyrosine-phosphorylated included phospholipase C (PLC-gamma 1), p95vav, ZAP-70, the MAP kinase, CD3 zeta and unidentified proteins of 120, 100 and 80 kDa. Tyrosine phosphorylation of the 120, 95 and 68 kDa proteins associated with PLC-gamma 1 was also observed in these cells upon stimulation. In contrast, only the 100 kDa protein and the MAP kinase were increasingly tyrosine phosphorylated in the antigen-stimulated cells expressing t-1 fyn. These data suggest that PLC-gamma 1, PLC-gamma 1 associated molecules, p95vav, the 80 kDa protein, ZAP-70 and the CD3 zeta chain may be substrates of p59fyn or of other tyrosine kinases regulated by p59fyn and be important in T cell signaling.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigen-Antibody Complex / immunology
  • Antigen-Antibody Complex / metabolism
  • Flow Cytometry
  • Hybridomas / immunology
  • Immunoblotting
  • Interleukin-2 / biosynthesis*
  • Isoenzymes / metabolism
  • Lymphocyte Activation / immunology*
  • Mice
  • Phospholipase C gamma
  • Precipitin Tests
  • Protein-Tyrosine Kinases / metabolism*
  • Proto-Oncogene Proteins / metabolism*
  • Proto-Oncogene Proteins c-fyn
  • Receptor-CD3 Complex, Antigen, T-Cell / immunology
  • Signal Transduction / immunology*
  • T-Lymphocytes / immunology*
  • Transfection
  • Type C Phospholipases / metabolism


  • Antigen-Antibody Complex
  • Interleukin-2
  • Isoenzymes
  • Proto-Oncogene Proteins
  • Receptor-CD3 Complex, Antigen, T-Cell
  • Protein-Tyrosine Kinases
  • Fyn protein, mouse
  • Proto-Oncogene Proteins c-fyn
  • Type C Phospholipases
  • Phospholipase C gamma