An activated epidermal growth factor receptor/Lck chimera restores early T cell receptor-mediated calcium response in a CD45-deficient T cell line.
J Biol Chem
; 271(30): 17896-902, 1996 Jul 26.
Article
em En
| MEDLINE
| ID: mdl-8663450
ABSTRACT
In T cells, cell surface expression of CD45, a transmembrane tyrosine phosphatase, is required for T cell receptor (TCR) signal transduction. Indirect evidence suggests that CD45 function in TCR signaling involves the dephosphorylation of the C-terminal negative regulatory site of p56(lck), Tyr-505. To evaluate the importance of CD45-mediated dephosphorylation of p56(lck) Tyr-505 in TCR signaling, we established CD45(-) Jurkat cell lines expressing various forms of a chimera containing the extracellular and transmembrane domains of the epidermal growth factor receptor (EGFR) fused to p56(lck). We report that an activated EGFR/Lck chimera is able to reconstitute a Ca2+ response after CD3 stimulation in the absence of CD45 expression. In addition, the wild-type and kinase inactive versions of the EGFR/Lck chimera fail to restore early signaling. Restoration of the response by EGFR/LckF505 required EGF binding to the chimeric kinase. Altogether, these results provide the first direct evidence that the lack of efficient dephosphorylation of p56(lck) Tyr-505 is, in part, responsible for the unresponsiveness of CD45(-) cells. They also indicate that a second event is required for p56(lck) function in TCR signaling in addition to its dephosphorylation at Tyr-505.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Receptores de Antígenos de Linfócitos T
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Linfócitos T
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Cálcio
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Antígenos Comuns de Leucócito
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Quinases da Família src
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Receptores ErbB
Limite:
Humans
Idioma:
En
Revista:
J Biol Chem
Ano de publicação:
1996
Tipo de documento:
Article
País de afiliação:
Canadá
País de publicação:
EEUU
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ESTADOS UNIDOS
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ESTADOS UNIDOS DA AMERICA
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EUA
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UNITED STATES
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UNITED STATES OF AMERICA
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US
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USA