Functional Nanoscale Organization of Signaling Molecules Downstream of the T Cell Antigen Receptor

Immunity. 2011 Nov 23;35(5):705-20. doi: 10.1016/j.immuni.2011.10.004. Epub 2011 Nov 4.

Abstract

Receptor-regulated cellular signaling often is mediated by formation of transient, heterogeneous protein complexes of undefined structure. We used single and two-color photoactivated localization microscopy to study complexes downstream of the T cell antigen receptor (TCR) in single-molecule detail at the plasma membrane of intact T cells. The kinase ZAP-70 distributed completely with the TCRζ chain and both partially mixed with the adaptor LAT in activated cells, thus showing localized activation of LAT by TCR-coupled ZAP-70. In resting and activated cells, LAT primarily resided in nanoscale clusters as small as dimers whose formation depended on protein-protein and protein-lipid interactions. Surprisingly, the adaptor SLP-76 localized to the periphery of LAT clusters. This nanoscale structure depended on polymerized actin and its disruption affected TCR-dependent cell function. These results extend our understanding of the mechanism of T cell activation and the formation and organization of TCR-mediated signaling complexes, findings also relevant to other receptor systems.

Publication types

  • Research Support, N.I.H., Intramural

MeSH terms

  • Actins / metabolism
  • Adaptor Proteins, Signal Transducing / metabolism
  • Cell Line, Tumor
  • Cells, Cultured
  • Humans
  • Jurkat Cells
  • Lymphocyte Activation / immunology
  • Membrane Proteins / metabolism
  • Phospholipase C gamma / metabolism
  • Phosphoproteins / metabolism
  • Phosphorylation / immunology
  • Protein Binding
  • Protein Multimerization
  • Protein Transport
  • Receptors, Antigen, T-Cell / immunology*
  • Receptors, Antigen, T-Cell / metabolism*
  • Receptors, Antigen, T-Cell, gamma-delta / immunology
  • Receptors, Antigen, T-Cell, gamma-delta / metabolism
  • Signal Transduction*
  • T-Lymphocytes / immunology
  • T-Lymphocytes / metabolism
  • ZAP-70 Protein-Tyrosine Kinase / metabolism

Substances

  • Actins
  • Adaptor Proteins, Signal Transducing
  • LAT protein, human
  • Membrane Proteins
  • PALM protein, human
  • Phosphoproteins
  • Receptors, Antigen, T-Cell
  • Receptors, Antigen, T-Cell, gamma-delta
  • SLP-76 signal Transducing adaptor proteins
  • ZAP-70 Protein-Tyrosine Kinase
  • Phospholipase C gamma