title: Cutting edge: cell surface linker for activation of T cells is recruited to microclusters and is active in signaling.
abstract: A controversy has recently emerged regarding the location of the cellular pool of the adapter linker for activation of T cells (LAT) that participates in propagation of signals downstream of the TCR. In one model phosphorylation and direct recruitment of cell surface LAT to activation-induced microclusters is critical for T cell activation, whereas in the other model vesicular, but not surface, LAT participates in these processes. By using a chimeric version of LAT that can be tracked via an extracellular domain, we provide evidence that LAT located at the cell surface can be recruited efficiently to activation-induced microclusters within seconds of TCR engagement. Importantly, we also demonstrate that this pool of LAT at the plasma membrane is rapidly phosphorylated. Our results provide support for the model in which the cell utilizes LAT from the cell surface for rapid responses to TCR stimulation.
authors.affiliation: Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Lakshmi
authors.initials: L
authors.lastname: Balagopalan
authors.forename: Valarie A
authors.initials: VA
authors.lastname: Barr
authors.forename: Robert L
authors.initials: RL
authors.lastname: Kortum
authors.forename: Anna K
authors.initials: AK
authors.lastname: Park
authors.forename: Lawrence E
authors.initials: LE
authors.lastname: Samelson
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000502:physiology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D007424:Intracellular Fluid / Q000276:immunology / Q000378:metabolism; D019169:Jurkat Cells; D008213:Lymphocyte Activation / Q000235:genetics / Q000276:immunology*; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology*; D010766:Phosphorylation / Q000235:genetics / Q000276:immunology; D021381:Protein Transport / Q000235:genetics / Q000276:immunology; D011948:Receptors, Antigen, T-Cell / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics / Q000276:immunology*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C110810:LAT protein, human; D008565:Membrane Proteins; D011948:Receptors, Antigen, T-Cell; D011993:Recombinant Fusion Proteins