Tandem SH2 domains of ZAP-70 bind to T cell antigen receptor zeta and CD3 epsilon from activated Jurkat T cells.
A proximal and critical biochemical event upon T cell antigen receptor (TCR) stimulation is the activation of a protein tyrosine kinase (PTK) pathway. ZAP-70, a PTK of the p72syk family, associates with phosphorylated TCR subunits upon TCR stimulation. Here we report that the tandem SH2 domains of ZAP-70, expressed as a fusion protein, bind to tyrosine-phosphorylated CD3 epsilon and TCR zeta from activated Jurkat T cell lysates. The single N- and C-terminal SH2 domains of ZAP-70, expressed separately, do not bind these TCR subunits. In comparison to fusion proteins containing SH2 domains from other proteins, the tandem SH2 domains of ZAP-70 demonstrate a remarkably restricted repertoire of protein binding, binding only TCR zeta and CD3 epsilon. ZAP-70 is also recovered in the binding assay, but this is likely to be a consequence of its interaction with multiple SH2 binding sites on the zeta-zeta and CD3 epsilon-containing dimers.
Wange
R L
RL
Cell Biology and Metabolism Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892.
Malek
S N
SN
Desiderio
S
S
Samelson
L E
LE
D000595:Amino Acid Sequence; D015703:Antigens, CD / Q000378:metabolism*; D017252:CD3 Complex / Q000378:metabolism*; D005982:Glutathione Transferase / Q000302:isolation & purification / Q000378:metabolism; D006801:Humans; D008213:Lymphocyte Activation; D008969:Molecular Sequence Data; D010766:Phosphorylation; D010957:Plasmids; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000302:isolation & purification / Q000378:metabolism; D013438:Sulfhydryl Compounds; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D051746:ZAP-70 Protein-Tyrosine Kinase
D015703:Antigens, CD; D017252:CD3 Complex; D011948:Receptors, Antigen, T-Cell; D011993:Recombinant Fusion Proteins; D013438:Sulfhydryl Compounds; D005982:Glutathione Transferase; D011505:Protein-Tyrosine Kinases; D051746:ZAP-70 Protein-Tyrosine Kinase; C497261:ZAP70 protein, human