The 21- and 23-kD forms of TCR zeta are generated by specific ITAM phosphorylations.
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.
van Oers
N S
NS
Center for Immunology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA. oers@utsw.swmed.edu
Tohlen
B
B
Malissen
B
B
Moomaw
C R
CR
Afendis
S
S
Slaughter
C A
CA
D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism*; D051379:Mice; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D010766:Phosphorylation; D011948:Receptors, Antigen, T-Cell / Q000235:genetics* / Q000378:metabolism*; D015398:Signal Transduction
D008565:Membrane Proteins; D011948:Receptors, Antigen, T-Cell; C054979:antigen T cell receptor, zeta chain