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Updated: Dec 2, 2025
Massively Parallel Reporter Assays in Cultured Mammalian Cells
Published on: August 17, 2014
Nr4a1 and Nr4a3 Reporter Mice Are Differentially Sensitive to T Cell Receptor Signal Strength and Duration
Emma Jennings1, Thomas A E Elliot1, Natasha Thawait1
1Institute of Immunology and Immunotherapy, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK.
Abstract:
Nr4a receptors are activated by T cell receptor (TCR) signaling and play key roles in T cell differentiation. Which TCR signaling pathways regulate Nr4a receptors and their sensitivities to TCR signal strength and duration remains unclear. Using Nr4a1/Nur77-GFP and Nr4a3-Timer of cell kinetics and activity (Tocky) mice, we elucidate the signaling pathways governing Nr4a receptor expression. We reveal that Nr4a1-Nr4a3 are Src family kinase dependent. Moreover, Nr4a2 and Nr4a3 are attenuated by calcineurin inhibitors and bind nuclear factor of activated T cells 1 (NFAT1), highlighting a necessary and sufficient role for NFAT1 in the control of Nr4a2 and Nr4a3, but redundancy for Nr4a1. Nr4a1-GFP is activated by tonic and cognate signals during T cell development, whereas Nr4a3-Tocky requires cognate peptide:major histocompatibility complex (MHC) interactions for expression. Compared to Nr4a3-Tocky, Nr4a1-GFP is approximately 2- to 3-fold more sensitive to TCR signaling and is detectable by shorter periods of TCR signaling. These findings suggest that TCR signal duration may be an underappreciated aspect influencing the developmental fate of T cells in vivo.
Insights
T-cell receptor (TCR) signaling pathways regulate Nr4a receptor expression. Nr4a1 and Nr4a3 show differential sensitivity to TCR signal strength and duration, impacting T-cell development.
Area of Science:
- Immunology
- Molecular Biology
- Cell Signaling
Background:
- Nuclear receptor subfamily 4, group A (Nr4a) receptors are crucial for T-cell differentiation.
- The specific T-cell receptor (TCR) signaling pathways governing Nr4a receptor expression and their sensitivity to signal parameters remain incompletely understood.
Purpose of the Study:
- To elucidate the TCR signaling pathways regulating Nr4a receptor expression.
- To investigate the differential sensitivity of Nr4a receptors to TCR signal strength and duration.
Main Methods:
- Utilized Nr4a1/Nur77-GFP and Nr4a3-Timer of cell kinetics and activity (Tocky) mouse models.
- Investigated Src family kinase (SFK) and calcineurin/NFAT signaling pathways.
- Assessed Nr4a receptor activation in response to varying TCR signaling conditions.
Main Results:
- Nr4a1-Nr4a3 expression is dependent on Src family kinases.
- Nuclear factor of activated T-cells 1 (NFAT1) is necessary and sufficient for Nr4a2 and Nr4a3 regulation, with redundancy for Nr4a1.
- Nr4a1 exhibits higher sensitivity to TCR signaling strength and duration compared to Nr4a3.
Conclusions:
- TCR signal duration is a critical, potentially underappreciated, factor in T-cell development.
- Differential Nr4a receptor regulation by TCR signaling pathways provides insights into T-cell fate determination.
