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Identification of Mediators of T-cell Receptor Signaling via the Screening of Chemical Inhibitor Libraries
Published on: January 22, 2019
Quantitative interactomics in primary T cells unveils TCR signal diversification extent and dynamics
Guillaume Voisinne1, Kristof Kersse1, Karima Chaoui2
1Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, INSERM, CNRS, Marseille, France.
Abstract:
The activation of T cells by the T cell antigen receptor (TCR) results in the formation of signaling protein complexes (signalosomes), the composition of which has not been analyzed at a systems level. Here, we isolated primary CD4+ T cells from 15 gene-targeted mice, each expressing one tagged form of a canonical protein of the TCR-signaling pathway. Using affinity purification coupled with mass spectrometry, we analyzed the composition and dynamics of the signalosomes assembling around each of the tagged proteins over 600 s of TCR engagement. We showed that the TCR signal-transduction network comprises at least 277 unique proteins involved in 366 high-confidence interactions, and that TCR signals diversify extensively at the level of the plasma membrane. Integrating the cellular abundance of the interacting proteins and their interaction stoichiometry provided a quantitative and contextual view of each documented interaction, permitting anticipation of whether ablation of a single interacting protein can impinge on the whole TCR signal-transduction network.
Insights
This study maps the T cell receptor (TCR) signalosome, revealing 277 proteins and 366 interactions. Understanding this network helps predict how protein changes impact T cell signaling.
Area of Science:
- Immunology
- Molecular Biology
- Systems Biology
Background:
- T cell activation via the T cell receptor (TCR) initiates complex signaling cascades.
- The precise composition and dynamics of these signaling complexes (signalosomes) remain incompletely understood at a systems level.
Purpose of the Study:
- To comprehensively map the protein composition and interactions within the TCR signalosome.
- To analyze the dynamics of signalosome assembly upon TCR engagement.
- To provide a quantitative framework for understanding TCR signal transduction.
Main Methods:
- Primary CD4+ T cells were isolated from gene-targeted mice expressing tagged TCR-signaling proteins.
- Affinity purification coupled with mass spectrometry (AP-MS) was employed to identify interacting proteins.
- Quantitative analysis integrated protein abundance and interaction stoichiometry.
Main Results:
- The TCR signal-transduction network comprises at least 277 unique proteins.
- A total of 366 high-confidence protein-protein interactions within the signalosome were identified.
- Extensive signal diversification occurs at the plasma membrane level during TCR engagement.
- Quantitative data allows prediction of the impact of single protein perturbations on the network.
Conclusions:
- This study presents the first systems-level analysis of the TCR signalosome.
- The findings reveal the complexity and compartmentalization of TCR signaling.
- The quantitative framework provides novel insights into T cell activation mechanisms and potential therapeutic targets.
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