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Sci. Signal., 19 February 2013
Vol. 6, Issue 263, p. ra13
[DOI: 10.1126/scisignal.2003607]


T Cell Activation Results in Conformational Changes in the Src Family Kinase Lck to Induce Its Activation

Anja Stirnweiss1*, Roland Hartig1, Steffi Gieseler1{dagger}, Jonathan A. Lindquist1, Peter Reichardt1, Lars Philipsen1, Luca Simeoni1, Mateusz Poltorak1, Camilla Merten1, Werner Zuschratter2, Yury Prokazov2, Wolfgang Paster3{ddagger}, Hannes Stockinger3, Thomas Harder1, Matthias Gunzer1§, and Burkhart Schraven1,4||

1 Institute of Molecular and Clinical Immunology, Otto von Guericke University, Leipziger Strasse 44, 39120 Magdeburg, Germany.
2 Leibniz Institute for Neurobiology, Brenneckestrasse 6, 39118 Magdeburg, Germany.
3 Molecular Immunology Unit, Institute for Hygiene and Applied Immunology, Center for Physiology, Pathophysiology, and Immunology, Medical University of Vienna, Lazarettgasse 19, A-1090 Vienna, Austria.
4 Department of Immune Control, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany.

* Present address: Division of Children’s Leukaemia and Cancer Research, Telethon Institute for Child Health Research, 100 Roberts Road, Subiaco, WA 6008, Australia.

{dagger} Present address: Children’s Hospital, Otto von Guericke University, Leipziger Strasse 44, 39120 Magdeburg, Germany.

{ddagger} Present address: T Cell Signalling Laboratory, Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK.

§ Present address: Institute for Experimental Immunology and Imaging, University Hospital, University of Duisburg/Essen, Universitätsstraße 2, 45117 Essen, Germany.

Abstract: The lymphocyte-specific Src family protein tyrosine kinase p56Lck (Lck) is essential for T cell development and activation and, hence, for adaptive immune responses. The mechanism by which Lck activity is directed toward specific substrates in response to T cell receptor (TCR) activation remains elusive. We used fluorescence lifetime imaging microscopy to assess the activation-dependent spatiotemporal changes in the conformation of Lck in live human T cells. Kinetic analysis of the fluorescence lifetime of Lck biosensors enabled the direct visualization of the dynamic local opening of 20% of the total amount of Lck proteins after activation of T cells with antibody against CD3 or by superantigen-loaded antigen-presenting cells. Parallel biochemical analysis of TCR complexes revealed that the conformational changes in Lck correlated with the induction of Lck enzymatic activity. These data show the dynamic, local activation through conformational change of Lck at sites of TCR engagement.

|| To whom correspondence should be addressed. E-mail: Burkhart.Schraven{at}

Citation: A. Stirnweiss, R. Hartig, S. Gieseler, J. A. Lindquist, P. Reichardt, L. Philipsen, L. Simeoni, M. Poltorak, C. Merten, W. Zuschratter, Y. Prokazov, W. Paster, H. Stockinger, T. Harder, M. Gunzer, B. Schraven, T Cell Activation Results in Conformational Changes in the Src Family Kinase Lck to Induce Its Activation. Sci. Signal. 6, ra13 (2013).

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