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Updated: Jul 11, 2026

Measuring TCR-pMHC Binding In Situ using a FRET-based Microscopy Assay
Published on: October 30, 2015
Fyn regulates the duration of TCR engagement needed for commitment to effector function
Andrew Filby1, Benedict Seddon, Joanna Kleczkowska
1Division of Molecular Immunology, Medical Research Council, National Institute for Medical Research, The Ridgeway, London, United Kingdom.
T cell activation requires sustained signaling. This study reveals the Src family kinase Fyn opposes T cell proliferation and IL-2 production, acting as a brake on T cell receptor signaling.
Area of Science:
- Immunology
- Molecular Biology
- Cell Signaling
Background:
- T cell activation involves T cell receptor (TCR) signaling, leading to proliferation and cytokine production.
- Full T cell activation requires sustained receptor contact for several hours, but the underlying biochemical mechanisms remain unclear.
Purpose of the Study:
- To investigate the molecular basis for the transition from transient signaling to sustained T cell activation.
- To elucidate the roles of Src family kinases, specifically Lck and Fyn, in CD8 T cell commitment to proliferation and IL-2 production.
Main Methods:
- Analysis of primary CD8 T cells.
- Investigating the role of sustained Src family kinase (Lck and Fyn) activation in T cell receptor (TCR) signaling.
- Assessing T cell proliferation and Interleukin-2 (IL-2) production.
Main Results:
- Sustained activation of Lck is necessary for CD8 T cell commitment to proliferation and IL-2 production.
- The Src family kinase Fyn opposes this commitment, acting as a negative regulator.
- In the absence of Fyn, T cells exhibit accelerated commitment to activation, enhanced IL-2 production, and increased division rounds.
Conclusions:
- Fyn plays a critical role in modulating T cell responses to antigen (Ag) by opposing sustained activation.
- Understanding the balance between Lck and Fyn is crucial for comprehending T cell activation thresholds and maintaining immune tolerance.
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