Nature Immunology
1, 322 - 328 (2000)
doi:10.1038/79774
The 21- and 23-kD forms of TCR are generated by specific ITAM phosphorylationsNicolai S. C. van Oers1, 2, Brett Tohlen1, Bernard Malissen4, Carolyn R. Moomaw3, Steve Afendis3
& Clive A. Slaughter31
Center for Immunology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA. 2
Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA. 3
Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA. 4
Centre d'Immunologie, INSERM-CNRS de Marseille-Luminy, 13288, Marseille, France.
Correspondence should be addressed to Nicolai S. C. van Oers oers@utsw.swmed.eduThe T cell receptor (TCR)  subunit contains three immunoreceptor tyrosine-based activation motifs (ITAMs) that translate effective extracellular ligand binding into intracellular signals by becoming phosphorylated into 21- and 23-kD forms. We report here that the 21-kD form of TCR is generated by phosphorylation of the tyrosines in the second and third ITAMs, whereas the 23-kD form is formed by the additional phosphorylation of the membrane-proximal ITAM tyrosines. The stable formation of the 21- and 23-kD species requires the binding of the tandem SH2 domains of ZAP-70. We also report that TCR-mediated signaling processes can proceed independently of either the 21- or 23-kD species of TCR.
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