title: Lck regulates the tyrosine phosphorylation of the T cell receptor subunits and ZAP-70 in murine thymocytes.
abstract: The Src-family and Syk/ZAP-70 family of protein tyrosine kinases (PTK) are required for T cell receptor (TCR) functions. We provide evidence that the Src-family PTK Lck is responsible for regulating the constitutive tyrosine phosphorylation of the TCR zeta subunit in murine thymocytes. Moreover, ligation of the TCR expressed on thymocytes from Lck-deficient mice largely failed to induce the phosphorylation of TCR-zeta, CD3 epsilon, or ZAP-70. In contrast, we find that the TCR-zeta subunit is weakly constitutively tyrosine phosphorylated in peripheral T cells isolated from Lck-null mice. These data suggest that Lck has a functional role in regulation of TCR signal transduction in thymocytes. In peripheral T cells, other Src-family PTKs such as Fyn may partially compensate for the absence of Lck.
authors.affiliation: Department of Medicine, University of California, San Francisco, 94143,USA.
authors.forename: N S
authors.initials: NS
authors.lastname: van Oers
authors.forename: N
authors.initials: N
authors.lastname: Killeen
authors.forename: A
authors.initials: A
authors.lastname: Weiss
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D005434:Flow Cytometry; D015151:Immunoblotting; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck); D008565:Membrane Proteins / Q000302:isolation & purification / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010766:Phosphorylation; D019000:Phosphotyrosine / Q000032:analysis / Q000378:metabolism; D017260:Receptor-CD3 Complex, Antigen, T-Cell / Q000276:immunology / Q000378:metabolism; D011948:Receptors, Antigen, T-Cell / Q000302:isolation & purification / Q000378:metabolism*; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D013950:Thymus Gland / Q000276:immunology; D014443:Tyrosine / Q000378:metabolism; D019061:src-Family Kinases / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*
chemical_list: D008565:Membrane Proteins; D017260:Receptor-CD3 Complex, Antigen, T-Cell; D011948:Receptors, Antigen, T-Cell; C054979:antigen T cell receptor, zeta chain; D019000:Phosphotyrosine; D014443:Tyrosine; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck); D019061:src-Family Kinases