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Trop S , Rhodes M , Wiest DL , Hugo P , Zuniga-Pflucker JC
Competitive displacement of pT alpha by TCR-alpha during TCR assembly prevents surface coexpression of pre-TCR and alpha beta TCR
Journal of Immunology. 2000 Nov 15;165(10) :5566-5572
PMID: ISI:000165254600025   
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During alpha beta T cell development, CD4(-)CD8(-) thymocytes first express pre-TCR (pT alpha /TCR-beta) before their differentiation to the CD4(+)CD8(+) stage. Positive selection of self-tolerant T cells is then determined by the alpha beta TCR expressed on CD4(+)CD8(+) thymocytes. Conceivably, an overlap in surface expression of these two receptors would interfere with the delicate balance of thymic selection. Therefore, a mechanism ensuring the sequential expression of pre-TCR and TCR must function during thymocyte development. In support of this notion, we demonstrate that expression of TCR- alpha by immature thymocytes terminates the surface expression of pre-TCR, Our results reveal that expression of TCR-alpha precludes the formation of pT alpha /TCR-beta dimers within the endoplasmic reticulum, leading to the displacement of pre-TCR from the cell surface. These findings illustrate a novel posttranslational mechanism for the regulation of pre-TCR expression, which may ensure that alpha beta TCR expression on thymocytes undergoing selection is not compromised by the expression of pre-TCR.
Times Cited: 12 English Article 372VK J IMMUNOL