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The Phosphatase Domains of CD45 are Required for Ligand Induced T‐Cell Receptor Downregulation
Author(s) -
; Kastrup,
Lauritsen,
Menné,
Alexander Dietrich,
Carsten Geisler
Publication year - 2000
Publication title -
scandinavian journal of immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.934
H-Index - 88
eISSN - 1365-3083
pISSN - 0300-9475
DOI - 10.1046/j.1365-3083.2000.00716.x
Subject(s) - t cell receptor , microbiology and biotechnology , protein tyrosine phosphatase , downregulation and upregulation , ligand (biochemistry) , phosphatase , signal transduction , biology , t cell , intracellular , receptor , extracellular , chemistry , phosphorylation , biochemistry , immunology , gene , immune system
Down‐regulation of the T‐cell receptor (TCR) plays an important role in modulating T‐cell responses, both during T‐cell development and in mature T cells. At least two distinct pathways exist for TCR down‐regulation: down‐regulation following TCR ligation; and down‐regulation following activation of protein kinase C (PKC). Ligand‐induced TCR down‐regulation is dependent on protein tyrosine kinase (PTK) activity and seems to be closely related to T‐cell activation. In addition, previous studies have indicated that ligand‐induced TCR down‐regulation is dependent on the expression of CD45, a transmembrane protein tyrosine phosphatase. The role of the different domains of CD45 in TCR down‐regulation was investigated in this study. We found that the phosphatase domains of CD45 are required for efficient ligand‐induced TCR down‐regulation. In contrast, the extracellular domain of CD45 is dispensable for ligand‐mediated TCR down‐regulation. Finally, PKC‐mediated TCR down‐regulation was found to be independent of both the extra‐and intracellular domains of CD45.