title: Early phosphorylation kinetics of proteins involved in proximal TCR-mediated signaling pathways.
abstract: Activation of T cells via the stimulation of the TCR plays a central role in the adaptive immunological response. Although much is known about TCR-stimulated signaling pathways, there are still gaps in our knowledge about the kinetics and sequence of events during early activation and about the in vivo specificity of kinases involved in these proximal signaling pathways. This information is important not only for understanding the activation of signaling pathways important for T cell function but also for the development of drug targets and computer-based molecular models. In this study, phospho-specific Abs directed toward individual sites on signaling proteins were used to investigate the early phosphorylation kinetics of proteins involved in proximal TCR-induced pathways. These studies indicate that linker for activation of T cells' tyrosines have substantially different phosphorylation kinetics and that Src homology 2 domain-containing leukocyte protein of 76 kDa has rapid, transient phosphorylation kinetics compared to other proteins. In additions, we provide evidence that ZAP-70 is the primary in vivo kinase for LAT tyrosine 191 and that Itk plays a role in the phosphorylation of tyrosine 783 on phospholipase C-gamma1. In total, these studies give new insight into the sequence, kinetics and specificity of early TCR-mediated signaling events that are vital for T cell activation.
authors.affiliation: Laboratory of Cellular and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Jon C D
authors.initials: JC
authors.lastname: Houtman
authors.forename: Richard A
authors.initials: RA
authors.lastname: Houghtling
authors.forename: Mira
authors.initials: M
authors.lastname: Barda-Saad
authors.forename: Yoko
authors.initials: Y
authors.lastname: Toda
authors.forename: Lawrence E
authors.initials: LE
authors.lastname: Samelson
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000276:immunology / Q000378:metabolism / Q000502:physiology; D000906:Antibodies / Q000378:metabolism; D000918:Antibody Specificity; D006801:Humans; D019169:Jurkat Cells; D007700:Kinetics; D008565:Membrane Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism / Q000502:physiology; D051966:Phospholipase C gamma / Q000276:immunology / Q000378:metabolism / Q000502:physiology; D010750:Phosphoproteins / Q000172:deficiency / Q000235:genetics / Q000276:immunology / Q000378:metabolism* / Q000502:physiology; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000096:biosynthesis / Q000235:genetics / Q000494:pharmacology; D050721:Proto-Oncogene Proteins c-cbl / Q000276:immunology / Q000378:metabolism / Q000502:physiology; D051567:Proto-Oncogene Proteins c-vav / Q000172:deficiency / Q000235:genetics; D034741:RNA, Small Interfering / Q000494:pharmacology; D011948:Receptors, Antigen, T-Cell / Q000502:physiology*; D015398:Signal Transduction / Q000235:genetics / Q000276:immunology*; D013601:T-Lymphocytes / Q000378:metabolism; D014443:Tyrosine / Q000378:metabolism; D051746:ZAP-70 Protein-Tyrosine Kinase / Q000172:deficiency / Q000276:immunology / Q000378:metabolism
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D000906:Antibodies; C110810:LAT protein, human; D008565:Membrane Proteins; D010750:Phosphoproteins; D051567:Proto-Oncogene Proteins c-vav; D034741:RNA, Small Interfering; D011948:Receptors, Antigen, T-Cell; C092947:SLP-76 signal Transducing adaptor proteins; C496618:VAV1 protein, human; D014443:Tyrosine; D050721:Proto-Oncogene Proteins c-cbl; D011505:Protein-Tyrosine Kinases; D051746:ZAP-70 Protein-Tyrosine Kinase; C497261:ZAP70 protein, human; C080813:emt protein-tyrosine kinase; D051966:Phospholipase C gamma; C067419:CBL protein, human