Ssu72 is a T-cell receptor-responsive modifier that is indispensable for regulatory T cells

Area of Science:

• Immunology
• Cell Biology
• Molecular Biology

Background:

• The balance between effector T cells and regulatory T cells (Tregs) is essential for adaptive immunity.
• Epigenetic mechanisms regulating Treg development, peripheral expression, and suppressive activity remain incompletely understood.

Purpose of the Study:

• To investigate the role of Ssu72 phosphatase in T-cell receptor (TCR) signaling and Treg homeostasis.
• To elucidate the molecular mechanisms by which Ssu72 influences Treg differentiation and function.

Main Methods:

• T-cell specific deletion of Ssu72.
• Analysis of T-cell differentiation, cytokine production (IL-2, IFNγ), and Treg markers (Foxp3).
• Investigation of protein-protein interactions between Ssu72 and PLCγ1.

Main Results:

• Ssu72 phosphatase is activated by TCR and IL-2R signaling pathways and localizes to the cell membrane.
• Ssu72 deletion in T cells leads to reduced Treg differentiation and increased effector cytokine production.
• Ssu72 forms a complex with PLCγ1, and its deficiency impairs PLCγ1 signaling and Foxp3 induction.
• Downregulation of Ssu72 correlates with defects in mucosal tolerance in patients.

Conclusions:

• Ssu72 plays a critical role in coordinating Treg differentiation and function through modulation of TCR signaling and cytokine responses.
• The Ssu72-PLCγ1 interaction is crucial for Treg development and maintaining peripheral immune tolerance.