TCR microclusters form spatially segregated domains and sequentially assemble in calcium-dependent kinetic steps

Nat Commun. 2019 Jan 17;10(1):277. doi: 10.1038/s41467-018-08064-2.

Abstract

Engagement of the T cell receptor (TCR) by stimulatory ligand results in the rapid formation of microclusters at sites of T cell activation. Whereas microclusters have been studied extensively using confocal microscopy, the spatial and kinetic relationships of their signaling components have not been well characterized due to limits in image resolution and acquisition speed. Here we show, using TIRF-SIM to examine the organization of microclusters at sub-diffraction resolution, the presence of two spatially distinct domains composed of ZAP70-bound TCR and LAT-associated signaling complex. Kinetic analysis of microcluster assembly reveal surprising delays between the stepwise recruitment of ZAP70 and signaling proteins to the TCR, as well as distinct patterns in their disassociation. These delays are regulated by intracellular calcium flux downstream of T cell activation. Our results reveal novel insights into the spatial and kinetic regulation of TCR microcluster formation and T cell activation.

Publication types

  • Research Support, N.I.H., Intramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / genetics
  • Adaptor Proteins, Signal Transducing / metabolism
  • Calcium / immunology
  • Calcium / metabolism*
  • Feedback, Physiological
  • Gene Knockout Techniques
  • Humans
  • Image Processing, Computer-Assisted
  • Intravital Microscopy / methods
  • Jurkat Cells
  • Kinetics
  • Leukocytes, Mononuclear
  • Lymphocyte Activation / physiology*
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism
  • Microscopy, Fluorescence
  • Primary Cell Culture
  • Protein Domains / physiology
  • Receptors, Antigen, T-Cell / immunology
  • Receptors, Antigen, T-Cell / metabolism*
  • Signal Transduction / immunology
  • T-Lymphocytes / immunology*
  • T-Lymphocytes / metabolism
  • ZAP-70 Protein-Tyrosine Kinase / immunology
  • ZAP-70 Protein-Tyrosine Kinase / metabolism*

Substances

  • Adaptor Proteins, Signal Transducing
  • LAT protein, human
  • Membrane Proteins
  • Receptors, Antigen, T-Cell
  • ZAP-70 Protein-Tyrosine Kinase
  • ZAP70 protein, human
  • Calcium