Dynamics of p56lck Translocation to the T Cell Immunological Synapse following Agonist and Antagonist Stimulation

Program in Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA.
Immunity (Impact Factor: 21.56). 01/2003; 17(6):809-22. DOI: 10.1016/S1074-7613(02)00481-8
Source: PubMed


To study the spatio/temporal recruitment of lck during immunological synapse formation, we utilize high-speed time-lapse microscopy to visualize green fluorescent protein (GFP) fusions of lck and CD3zeta following agonist or altered peptide ligand (APL) stimulation. The dynamics of lck and CD3zeta recruitment are comparable; however, lck becomes excluded to the periphery of mature synapses, while most CD3zeta is centrally localized, suggesting a limited time frame within which lck can efficiently phosphorylate CD3 molecules during synapse maturation. Exposure of T cells to specific APLs affects the efficiency of conjugate formation and lck accumulation. Most surprisingly, we find an intracellular pool of lck associated with recycling endosomes that translocates to mature synapses within 10 min of calcium flux. This bolus of lck may contribute to intermediate-late signal transduction.

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Available from: Lauren I R Ehrlich,
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    • "These observations could be explained by the multistage role of Lck in T cell activation signaling based on the two pools of Lck detected at the immunological synapse, that is, the central pool and the peripheral pool. Lck may have a dual role where, early in TCR engagement, the central Lck pool participates in the initiation and activation of downstream signaling molecules and the peripheral Lck pool downregulates TCR-dependent signaling [49]. "
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    • "In addition, the fact that CD8 does not bind MHC to stabilize TCR binding until after signaling has started argues this point strongly (Jiang et al., 2011). Lck can be co-precipitated with TCR/CD3 in mild detergents (Schraven et al., 1993; Stefanova et al., 2003), but although Lck can be co-capped with co-receptor (after crosslinking by suitable antibody), it does not co-cap with TCR (Ehrlich et al., 2002). Fyn can also be co-precipitated with the TCR in mild detergents (Samelson et al., 1990 "
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    • "In addition, an SNX27 pool is recruited to the cell–cell contact area within ~2–3 minutes after an encounter with pulsed APCs. These results are reminiscent of studies showing that components of the TCR signalling machinery (including LAT, p56lck and CD3, which similarly to SNX27 codistribute with transferrin) are recruited to the immunological synapse with kinetics similar to that observed here (Anton et al., 2008; Bonello et al., 2004; Das et al., 2004; Ehrlich et al., 2002). The subcellular distribution of GFP–SNX27 resembled that of endogenous SNX27, which excludes artefacts caused by the GFP tag. "
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