The Vav binding site (Y315) in ZAP-70 is critical for antigen receptor-mediated signal transduction.
Stimulation of antigen receptors in T and B cells leads to the activation of the Src and Syk families of protein tyrosine kinases (PTK). These PTKs subsequently phosphorylate numerous intracellular substrates, including the 95-kD protooncogene product Vav. Vav is essential for both T and B cell development and T and B cell antigen receptor-mediated signal transduction. After receptor ligation, Vav associates with phosphorylated Syk and ZAP-70 PTKs, an interaction that depends upon its SH2 domain. Here we demonstrate that a point mutation of tyrosine 315 (Y315F) in ZAP-70, a putative Vav SH2 domain binding site, eliminated the Vav- ZAP-70 interaction. Moreover, the Y315 mutation impaired the function of ZAP-70 in antigen receptor signaling. Surprisingly, this mutation also resulted in marked reduction in the tyrosine phosphorylation of ZAP-70, Vav, SLP-76, and Shc. These data demonstrate that the Vav binding site in ZAP-70 plays a critical role in antigen receptor-mediated signal transduction.
Wu
J
J
Department of Microbiology and Immunology, University of California, San Francisco, California 94143, USA.
Zhao
Q
Q
Kurosaki
T
T
Weiss
A
A
D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D001665:Binding Sites; D018797:Cell Cycle Proteins; D002460:Cell Line; D005982:Glutathione Transferase / Q000096:biosynthesis; D006801:Humans; D007700:Kinetics; D008156:Luciferases / Q000096:biosynthesis; D008322:Mammals; D016297:Mutagenesis, Site-Directed; D009842:Oligopeptides; D010452:Peptide Biosynthesis; D010455:Peptides; D010750:Phosphoproteins / Q000096:biosynthesis / Q000502:physiology; D011505:Protein-Tyrosine Kinases / Q000737:chemistry / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D051567:Proto-Oncogene Proteins c-vav; D011947:Receptors, Antigen, B-Cell / Q000096:biosynthesis / Q000502:physiology*; D011948:Receptors, Antigen, T-Cell / Q000096:biosynthesis / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000276:immunology*; D014162:Transfection; D051746:ZAP-70 Protein-Tyrosine Kinase; D018909:src Homology Domains
D048868:Adaptor Proteins, Signal Transducing; D018797:Cell Cycle Proteins; D009842:Oligopeptides; D010455:Peptides; D010750:Phosphoproteins; D011518:Proto-Oncogene Proteins; D051567:Proto-Oncogene Proteins c-vav; D011947:Receptors, Antigen, B-Cell; D011948:Receptors, Antigen, T-Cell; D011993:Recombinant Fusion Proteins; C092947:SLP-76 signal Transducing adaptor proteins; C496618:VAV1 protein, human; C085706:FLAG peptide; D008156:Luciferases; D005982:Glutathione Transferase; D011505:Protein-Tyrosine Kinases; D051746:ZAP-70 Protein-Tyrosine Kinase; C497261:ZAP70 protein, human