Physical and functional interactions of protein tyrosine kinases, p59fyn and ZAP-70, in T cell signaling

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Updated: Oct 2, 2026

In Vitro Analysis of PDZ-dependent CFTR Macromolecular Signaling Complexes
10:05

In Vitro Analysis of PDZ-dependent CFTR Macromolecular Signaling Complexes

Published on: August 13, 2012

N Fusaki1, S Matsuda, H Nishizumi

  • 1Department of Oncology, University of Tokyo, Japan.

Journal of Immunology (Baltimore, Md. : 1950)
|February 15, 1996
PubMed

Insights

Src family kinases like p59fyn (Fyn) are crucial for T-cell receptor (TCR) signaling. This study reveals Fyn associates with ZAP-70 upon TCR stimulation, enhancing T-cell activation through phosphorylation.

Area of Science:

  • Molecular Biology
  • Immunology
  • Cell Signaling

Background:

  • Src family protein tyrosine kinases regulate signaling pathways initiated by cell surface receptors lacking intrinsic kinase domains.
  • p59fyn (Fyn), a Src family kinase, is vital for T-cell receptor (TCR)-mediated signaling.

Purpose of the Study:

  • To investigate the association between Fyn and zeta-associated tyrosine kinase (ZAP-70) during TCR-mediated signaling.
  • To elucidate the molecular mechanisms and functional consequences of Fyn-ZAP-70 interaction in T-cells.

Main Methods:

  • Co-expression of Fyn and ZAP-70 in T cell hybridomas and COS cells.
  • Stimulation assays to analyze protein-protein interactions and tyrosine phosphorylation.
  • Mutational analysis of Fyn and ZAP-70 domains (SH2, SH3) to assess their role in association.

Main Results:

  • Fyn transiently associates with ZAP-70 upon TCR stimulation in T cells, peaking within seconds and diminishing by 10 minutes.
  • Fyn and ZAP-70 interact when coexpressed in COS cells, independent of the zeta-chain.
  • Kinase activity and specific domains (Fyn's SH2 and SH3) are crucial for Fyn-ZAP-70 association; coexpression enhances HS1 tyrosine phosphorylation.

Conclusions:

  • The interaction between Fyn and ZAP-70 is mediated by multiple sites on both kinases and is relevant to TCR signaling.
  • Fyn likely phosphorylates and activates ZAP-70, indicating a cooperative role in TCR signal transduction.
  • This Fyn-ZAP-70 complex contributes to the phosphorylation of downstream targets like HS1, crucial for T-cell activation.

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