title: Differential requirements for ZAP-70 in TCR signaling and T cell development.
abstract: The Syk/ZAP-70 family of protein tyrosine kinases is indispensable for normal lymphoid development. Syk is necessary for the development of B cells and epithelial gammadelta T cells, whereas ZAP-70 is essential for the normal development of T cells and TCR signaling. In this study, we show that although development of the alphabeta lineage was arrested in the thymus, CD3-positive T cells, primarily of the gammadelta lineage, were present in the lymph nodes of mice lacking ZAP-70. Moreover, in the absence of ZAP-70, dendritic epidermal T cells were fewer in number and of abnormal morphology, and intestinal intraepithelial lymphocytes, normally containing a large proportion of gammadelta T cells, were markedly reduced. These data suggest that gammadelta T cells show a variable dependence upon ZAP-70 for their development. Biochemical analyses of thymocytes revealed a lack of basal zeta-chain tyrosine phosphorylation. However, several other substrates were inducibly tyrosine phosphorylated following TCR stimulation. Thus, TCR-mediated signaling in ZAP-70-deficient thymocytes is only partially impaired. These studies suggest that Syk compensates only partially for the loss of ZAP-70, and that there is an absolute requirement of ZAP-70 for alphabeta T cells and epithelial gammadelta T cells, but not for some gammadelta T cells in peripheral lymphoid tissues.
authors.affiliation: Howard Hughes Medical Institute, Department of Medicine, University of California, San Francisco 94143-0795, USA.
authors.forename: T A
authors.initials: TA
authors.lastname: Kadlecek
authors.forename: N S
authors.initials: NS
authors.lastname: van Oers
authors.forename: L
authors.initials: L
authors.lastname: Lefrancois
authors.forename: S
authors.initials: S
authors.lastname: Olson
authors.forename: D
authors.initials: D
authors.lastname: Finlay
authors.forename: D H
authors.initials: DH
authors.lastname: Chu
authors.forename: K
authors.initials: K
authors.lastname: Connolly
authors.forename: N
authors.initials: N
authors.lastname: Killeen
authors.forename: A
authors.initials: A
authors.lastname: Weiss
mesh_terms: D000818:Animals; D019070:Cell Lineage; D017637:Clonal Deletion; D003713:Dendritic Cells / Q000276:immunology / Q000473:pathology; D004792:Enzyme Precursors / Q000502:physiology; D004817:Epidermis / Q000276:immunology / Q000473:pathology; D005260:Female; D007153:Immunologic Deficiency Syndromes / Q000276:immunology / Q000473:pathology; D007421:Intestine, Small / Q000276:immunology / Q000473:pathology; D047908:Intracellular Signaling Peptides and Proteins; D008198:Lymph Nodes / Q000276:immunology / Q000473:pathology; D018655:Lymphocyte Count; D008221:Lymphoid Tissue / Q000276:immunology / Q000473:pathology*; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D011505:Protein-Tyrosine Kinases / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism*; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000276:immunology*; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000276:immunology*; D015398:Signal Transduction / Q000502:physiology*; D013154:Spleen / Q000276:immunology / Q000473:pathology; D000072377:Syk Kinase; D016176:T-Lymphocyte Subsets / Q000166:cytology / Q000276:immunology*; D013950:Thymus Gland / Q000276:immunology / Q000502:physiology; D051746:ZAP-70 Protein-Tyrosine Kinase
chemical_list: D004792:Enzyme Precursors; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D011948:Receptors, Antigen, T-Cell; D016693:Receptors, Antigen, T-Cell, alpha-beta; D016692:Receptors, Antigen, T-Cell, gamma-delta; C054979:antigen T cell receptor, zeta chain; D011505:Protein-Tyrosine Kinases; D000072377:Syk Kinase; C000606897:Syk protein, mouse; D051746:ZAP-70 Protein-Tyrosine Kinase; C497262:Zap70 protein, mouse