Tyrosine-phosphorylated Vav1 as a Point of Integration for T-cell Receptor- and CD28-mediated Activation of JNK, p38, and Interleukin-2 Transcription
<p>In this study we identified tyrosine-phosphorylated Vav1 as an early point of integration between the signaling routes triggered by the T-cell receptor and CD28 in human T-cell leukemia cells. Costimulation resulted in a prolonged and sustained phosphorylation and membrane localization of V...
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| Main Authors: | , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
June 16, 2000
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| In: |
The journal of biological chemistry
Year: 2000, Volume: 275, Issue: 24, Pages: 18160-18171 |
| ISSN: | 1083-351X |
| DOI: | 10.1074/jbc.275.24.18160 |
| Online Access: | Verlag, lizenzpflichtig, Volltext: https://doi.org/10.1074/jbc.275.24.18160 Verlag, lizenzpflichtig, Volltext: https://www.jbc.org/article/S0021-9258(19)83168-X/abstract 
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| Author Notes: | Steffen P. Hehner, Thomas G. Hofmann, Oliver Dienz, Wulf Dröge, and M. Lienhard Schmitz |
| Summary: | <p>In this study we identified tyrosine-phosphorylated Vav1 as an early point of integration between the signaling routes triggered by the T-cell receptor and CD28 in human T-cell leukemia cells. Costimulation resulted in a prolonged and sustained phosphorylation and membrane localization of Vav1 in comparison to T-cell receptor activation alone. T-cell stimulation induced the recruitment of Vav1 to an inducible multiprotein T-cell activation signaling complex at the plasma membrane. Vav1 activated the mitogen-activated protein kinases JNK and p38. The Vav1-mediated activation of JNK employed a pathway involving Rac, HPK1, MLK3, and MKK7. The costimulation-induced activation of p38 was inhibited by dominant negative forms of Vav1, Rac, and MKK6. Here we show that Vav1 also induces transcription factors that bind to the CD28RE/AP element contained in the interleukin-2 promoter. A detailed mutational analysis of Vav1 revealed a series of constitutively active and nonfunctional forms of Vav1. Almost all inactive versions were mutated in their Dbl homology domain and behaved as dominant negative mutants that impaired costimulation-induced activation of JNK, p38, and CD28RE/AP-dependent transcription. In contrast to NF-AT-dependent transcription, Vav1-mediated transcriptional induction of the CD28RE/AP element in the interleukin-2 promoter could only partially be inhibited by cyclosporin A, suggesting a dual role of Vav1 for controlling Ca<sup>2+</sup>-dependent and -independent events.</p> |
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| Item Description: | Gesehen am 03.02.2021 |
| Physical Description: | Online Resource |
| ISSN: | 1083-351X |
| DOI: | 10.1074/jbc.275.24.18160 |