Translation factor eIF4G2 directs CD8⁺ T cell lineage commitment by selectively enabling the IL-7 receptor response

Area of Science:

• Immunology
• Molecular Biology
• Cell Biology

Background:

• Interleukin-7 receptor (IL-7R) signaling is vital for T cell development in the thymus.
• The precise mechanisms controlling IL-7R cytokine responsiveness during T cell lineage commitment remain largely unknown.

Purpose of the Study:

• To identify key regulators of IL-7R signaling in T cell lineage commitment.
• To elucidate the role of translation factors in CD8+ T cell fate determination.

Main Methods:

• Analysis of eIF4G2 expression in thymocytes.
• Generation and analysis of T cell-specific eIF4G2 knockout mice.
• Assessment of IL-7 responsiveness and T cell lineage commitment markers.

Main Results:

• eIF4G2 expression is upregulated in double-positive thymocytes.
• T cell-specific deletion of eIF4G2 results in a blockade of CD8+ single positive thymocyte lineage commitment.
• eIF4G2 deficiency impairs IL-7 responsiveness by affecting the γc subunit and IL-7Rα mRNA levels.
• CD4+ lineage choice and T cell receptor (TCR) signaling remain unaffected.

Conclusions:

• eIF4G2 acts as a critical translational regulator of IL-7R signaling.
• This regulation is essential for enforcing faithful CD8+ T cell lineage commitment.
• eIF4G2 represents a pivotal checkpoint for T cell fate determination.