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Reversible Dimerization of EGFR Revealed by Single‐Molecule Fluorescence Imaging Using Quantum Dots
Author(s) -
Kawashima Nagako,
Nakayama Kenichi,
Itoh Kohji,
Itoh Tamitake,
Ishikawa Mitsuru,
Biju Vasudevanpillai
Publication year - 2010
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200902963
Subject(s) - förster resonance energy transfer , biophysics , quantum dot , epidermal growth factor receptor , epidermal growth factor , chemistry , single molecule fret , cell signaling , fluorescence microscope , fluorescence lifetime imaging microscopy , fluorescence , cell membrane , receptor , cell , signal transduction , materials science , nanotechnology , biology , biochemistry , physics , quantum mechanics
The current work explores intermolecular interactions involved in the lateral propagation of cell‐signaling by epidermal growth factor receptors (EGFRs). Activation of EGFRs by binding an EGF ligand in the extracellular domain of the EGFR and subsequent dimerization of the EGFR initiates cell‐signaling. We investigated interactions between EGFRs in living cells by using single‐molecule microscopy, Förster resonance energy transfer (FRET), and atomic force microscopy. By analyzing time‐correlated intensity and propagation trajectories of quantum dot (QD)‐labeled EGFR single molecules, we found that signaling dimers of EGFR [(EGF‐EGFR) 2 ] are continuously formed in cell membrane through reversible association of heterodimers [EGF(EGFR) 2 ]. Also, we found that the lateral propagation of EGFR activation takes place through transient association of a heterodimer with predimers [(EGFR) 2 ]. We varified the transient association between activated EGFR and predimers using FRET from QD‐labeled heterodimers to Cy5‐labeled predimers and correlated topography and fluorescence imaging. Without extended single‐molecule fluorescence imaging and by using bio‐conjugated QDs, reversible receptor dimerization in the lateral activation of EGFR remained obscured.