T cell receptor ligation induces the formation of dynamically regulated signaling assemblies

By S. Bunnell, David I. Hong, Julia R. Kardon, T. Yamazaki, C. McGlade, V. Barr, L. Samelson. Journal of Cell Biology, 2002

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Tcell antigen receptor (TCR) ligation initiates tyrosine kinase activation, signaling complex assembly, and immune synapse formation. Here, we studied the kinetics and mechanics of signaling complex formation in live Jurkat leukemic T cells using signaling proteins fluorescently tagged with variants of enhanced GFP (EGFP). Within seconds of contacting coverslips coated with stimulatory antibodies, T cells developed small, dynamically regulated clusters which were enriched in the TCR, phosphotyrosine, ZAP-70, LAT, Grb2, Gads, and SLP-76, excluded the lipid raft marker enhanced yellow fluorescent protein–GPI, and were competent to induce calcium elevations. LAT, Grb2, and Gads were transiently associated with the TCR. Although ZAP-70–containing clusters persisted for more than 20 min, photobleaching studies revealed that ZAP-70 continuously dissociated from and returned to these complexes. Strikingly, SLP-76 translocated to a perinuclear structure after clustering with the TCR. Our results emphasize the dynamically changing composition of signaling complexes and indicate that these complexes can form within seconds of TCR engagement, in the absence of either lipid raft aggregation or the formation of a central TCR-rich cluster.

Subfields: Immunology, Oncology

View Paper: https://www.semanticscholar.org/paper/fe893adeff4c79a6fe6dff6f6a70e22bf5ce9492

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Citations in the corpus

Liquid phase condensation in cell physiology and disease (2017, background): “During T cell receptor (TCR) signaling, signaling components become activated by a series of phosphorylation reactions, leading to the formation of micrometer- or submicrometer-sized clusters (137).”
T cell receptor-proximal signals are sustained in peripheral microclusters and terminated in the central supramolecular activation cluster. (2006, methodology): “TCR clusters formed rapidly, as indicated by clustering of TCR labeled with H57 Fab and direct visualization of fluorescent MHCp in the bilayer (Figures S1A-S1C in the Supplemental Data available with this article online) and translocated to the center of the IS (Figures 1A-1E and Movie S1),…”
Single-molecule microscopy reveals plasma membrane microdomains created by protein-protein networks that exclude or trap signaling molecules in T cells. (2005, neutral): “The former condition riggers actin-mediated cell spreading, induction of alcium transients, and tyrosine phosphorylation (Bunell et al., 2001; Bunnell et al., 2002), though it has been hown that a low, basal level of signaling occurs even n unstimulated Jurkat cells (Roose et al., 2003).”
Adhesion of membranes via receptor-ligand complexes: Domain formation, binding cooperativity, and active processes (2009, background): “Recent experiments indicate that the first T-cell activation signals coincide with the formation of TCR microclusters within the first seconds of T-cell adhesion [89, 90, 91, 92, 93, 94].”
Recruitment and activation of PLCγ1 in T cells: a new insight into old domains (2006, methodology): “This resulted in TCR clustering and recruitment of multiple signaling molecules to the points of contact with the stimulatory surface (Bunnell et al, 2002; Barda-Saad et al, 2005).”
Programmed cell death 1 forms negative costimulatory microclusters that directly inhibit T cell receptor signaling by recruiting phosphatase SHP2 (2012, background): “…we and others have revised this idea and proposed that T cell activation is induced by a minimal T cell activation unit, the TCR microcluster, which consists of TCRs and their proximal signaling molecules (Bunnell et al., 2002; Campi et al., 2005; Yokosuka et al., 2005; Yokosuka and Saito, 2010 ).”
T-cell-antigen recognition and the immunological synapse (2003, background): “Real-time ligation of TCR has been recently related to the buildup of signalling assemblies in Jurkat T cells stimulated with plate-bound antibod”
Newly generated T cell receptor microclusters initiate and sustain T cell activation by recruitment of Zap70 and SLP-76 (2005, methodology): “The dynamic recruitment of signaling molecules during the initial activation of T cells has been analyzed using Jurkat cells expressing various enhanced green fluorescent protein (EGFP) fusion proteins and stimulation with immobilized antibody to CD3 (anti-CD3”
CD28 and CTLA-4 coreceptor expression and signal transduction (2009, background): “Gads and SLP-76), while other complexes carrying ZAP-70 can transiently interact with the TCR or SLP-76 clusters (164, 165).”