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Updated: Jul 18, 2026

A TIRF Microscopy Technique for Real-time, Simultaneous Imaging of the TCR and its Associated Signaling Proteins
Published on: March 22, 2012
The 21- and 23-kD forms of TCR zeta are generated by specific ITAM phosphorylations
N S van Oers1, B Tohlen, B Malissen
1Center for Immunology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA. oers@utsw.swmed.edu
Abstract:
The T cell receptor (TCR) zeta 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 zeta 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 zeta.
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