Related Experiment Video
Updated: Oct 18, 2025
Measuring Mitochondrial Function of Naïve and Effector CD8 T Cells
Published on: March 28, 2025
SATB1-dependent mitochondrial ROS production controls TCR signaling in CD4 T cells
Taku Kuwabara1, Fumio Ishikawa2,3, Masataka Ikeda4
1Department of Molecular Immunology, Toho University School of Medicine, Tokyo, Japan kuwabara@med.toho-u.ac.jp.
Abstract:
Special AT-rich sequence binding protein-1 (SATB1) is localized to the nucleus and remodels chromatin structure in T cells. SATB1-deficient CD4 T cells cannot respond to TCR stimulation; however, the cause of this unresponsiveness is to be clarified. Here, we demonstrate that SATB1 is indispensable to proper mitochondrial functioning and necessary for the activation of signal cascades via the TCR in CD4 T cells. Naïve SATB1-deficient CD4 T cells contain fewer mitochondria than WT T cells, as the former do not express mitochondrial transcription factor A (TFAM). Impaired mitochondrial function in SATB1-deficient T cells subverts mitochondrial ROS production and SHP-1 inactivation by constitutive oxidization. Ectopic TFAM expression increases mitochondrial mass and mitochondrial ROS production and rescues defects in the antigen-specific response in the SATB1-deficient T cells. Thus, SATB1 is vital for maintaining mitochondrial mass and function by regulating TFAM expression, which is necessary for TCR signaling.
Insights
Special AT-rich sequence binding protein-1 (SATB1) is vital for T cell receptor (TCR) signaling. SATB1 regulates mitochondrial mass and function by controlling mitochondrial transcription factor A (TFAM) expression, essential for T cell activation.
Area of Science:
- Immunology
- Cell Biology
- Molecular Biology
Background:
- Special AT-rich sequence binding protein-1 (SATB1) is a nuclear protein involved in chromatin remodeling in T cells.
- SATB1-deficient CD4 T cells exhibit unresponsiveness to T cell receptor (TCR) stimulation, but the underlying mechanisms are unclear.
Purpose of the Study:
- To elucidate the role of SATB1 in CD4 T cell activation and TCR signaling.
- To investigate the impact of SATB1 deficiency on mitochondrial function in T cells.
Main Methods:
- Comparative analysis of SATB1-deficient and wild-type (WT) CD4 T cells.
- Assessment of mitochondrial mass, mitochondrial transcription factor A (TFAM) expression, and mitochondrial reactive oxygen species (ROS) production.
- Evaluation of TCR signaling pathway activation and antigen-specific T cell responses.
Main Results:
- SATB1-deficient naive CD4 T cells display reduced mitochondrial mass due to decreased TFAM expression.
- Impaired mitochondrial function in SATB1-deficient T cells leads to altered ROS production and SHP-1 inactivation.
- Restoration of TFAM expression in SATB1-deficient T cells rescued mitochondrial defects and restored antigen-specific responses.
Conclusions:
- SATB1 is essential for maintaining mitochondrial mass and function in CD4 T cells.
- SATB1 regulates TFAM expression, which is critical for TCR signaling and T cell activation.
- SATB1 plays a vital role in T cell responsiveness by ensuring proper mitochondrial health.
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