In:
The Journal of Immunology, The American Association of Immunologists, Vol. 165, No. 6 ( 2000-09-15), p. 3065-3072
Abstract:
The TCR is a constitutively recycling receptor meaning that a constant fraction of TCR from the plasma membrane is transported inside the cell at the same time as a constant fraction of TCR from the intracellular pool is transported to the plasma membrane. TCR recycling is affected by protein kinase C activity. Thus, an increase in protein kinase C activity affects TCR recycling kinetics leading to a new TCR equilibrium with a reduced level of TCR expressed at the T cell surface. Down-regulation of TCR expression compromises T cell activation. Conversely, TCR up-regulation is expected to increase T cell responsiveness. The purpose of this study was to identify and characterize potential pathways for TCR up-regulation. We found that ceramide affected TCR recycling dynamics and induced TCR up-regulation in a concentration- and time-dependent manner. Experiments applying phosphatase inhibitors indicated that ceramide-induced TCR up-regulation was most probably mediated by serine/threonine protein phosphatase 2A. Analyses of T cell variants demonstrated that TCR up-regulation was dependent on the presence of an intact CD3γ L-based motif and thus acted on TCR engaged in the recycling pathway. Finally, we showed that TCR up-regulation probably plays a physiological role by increasing T cell responsiveness. Thus, by affecting the TCR recycling kinetics, T cells have the potential both to up- and down-regulate TCR expression and thereby adjust T cell responsiveness.
Type of Medium:
Online Resource
ISSN:
0022-1767
,
1550-6606
DOI:
10.4049/jimmunol.165.6.3065
Language:
English
Publisher:
The American Association of Immunologists
Publication Date:
2000
detail.hit.zdb_id:
1475085-5
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