TCRα-CD3δε{lunate} association is the initial step in αβ dimer formation in murine T cells and is limiting in immature CD4⁺CD8⁺ thymocytes

The present study has examined the molecular events leading to formation of αβ dimers in normal murine thymocytes and mature T cells. We demonstrate that TCR assembly proceeds by initial association of TCRα with CD3δε{lunate} proteins and by association of TCRβ with CD3γε{lunate} proteins to form αδε{lunate} and βγε{lunate} trimers; these trimers then associate to form αδε{lunate}-βγε{lunate} complexes, within which α-β disulfide bond formation occurs. We also show that TCR-associated protein (TRAP) associates uniquely with CD3γε{lunate} pairs and that formation of βγε{lunate} trimers occurs subsequent to TRAP dissociation. Importantly, we document that the assembly step that is quantitatively limiting in CD4+CD8+ thymocytes is the initial association of TCRα with CD3δε{lunate} chains, which appears necessary to protect nascent TCRα proteins from accelerated degradation within the ER of immature thymocytes. © 1995.

Duke Scholars

Author Joseph Linton Roberts Pediatrics, Allergy and Immunology