Abstract
The T cell antigen receptor (TCR) has been shown to cluster both before and upon engagement with cognate antigens. However, the effect of TCR clustering on its activation remains poorly understood. Here, we used two-color photo-activated localization microscopy (PALM) to visualize individual molecules of TCR and ZAP-70, as a marker of TCR activation and phosphorylation, at the plasma membrane of uniformly activated T cells. Imaging and second-order statistics revealed that ZAP-70 recruitment and TCR activation localized inside TCR clusters. Live cell PALM imaging showed that the extent of localized TCR activation decreased, yet remained significant, with cell spreading. Using dynamic modeling and Monte-Carlo simulations we evaluated possible mechanisms of localized TCR activation. Our simulations indicate that localized TCR activation is the result of long-range cooperative interactions between activated TCRs, or localized activation by Lck and Fyn. Our results demonstrate the role of molecular clustering in cell signaling and activation, and are relevant to studying a wide range of multi-molecular complexes. This article is part of a Special Issue entitled: Nanoscale membrane organisation and signalling.
Original language | American English |
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Pages (from-to) | 810-821 |
Number of pages | 12 |
Journal | Biochimica et Biophysica Acta - Molecular Cell Research |
Volume | 1853 |
Issue number | 4 |
DOIs | |
State | Published - 1 Apr 2015 |
Bibliographical note
Funding Information:The authors would like to thank Zeiss, Harald Hess (HHMI, Janelia Farm) for providing the PALM software and Thorstan Wiegand (Helmholtz Centre for Environmental Research — UFZ) for providing us his point-pattern analyses software. This research was supported by Grant no. 321993 from the Marie Skłodowska-Curie actions of the European Commission , the Lejwa Fund for Biochemistry , and Grants no. 1417/13 and no. 1937/13 from the Israeli Science Foundation .
Publisher Copyright:
© 2014 Elsevier B.V.
Keywords
- Immune synapse
- Microcluster
- Modeling and simulation
- Nanocluster
- Photoactivated localization microscopy
- Super-resolution light microscopy
- T cell activation
- T cell receptor