Nano-Scale Dynamic Recognition Imaging on Vascular Endothelial Cells
Lilia A. Chtcheglova 1, Jens Waschke 2, Linda Wildling 1, Detlev Drenckhahn 3 and Peter Hinterdorfer 1*
1 Johannes Kepler University of Linz
2 University of Würzburg
3 University Of Würzburg
* To whom correspondence should be addressed. E-mail: peter.hinterdorfer{at}jku.at.
Submitted on March 28, 2007
Revised on April 24, 2007
Accepted on 4 May 2007
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Abstract |
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Combination of high-resolution atomic force microscope (AFM) topography imaging with single molecule force spectroscopy provides a unique possibility for the detection of specific molecular recognition events. The identification and localization of specific receptor binding sites on complex heterogeneous biosurfaces such as cells and membranes are of particular interest in this context. Here simultaneous topography and recognition imaging (TREC) was applied to gently fixed microvascular endothelial cells from mouse myocardium (MyEnd) in order to identify binding sites of vascular endothelial (VE)-cadherin, known to play a crucial role in calcium-dependent, homophilic cell-to-cell adhesion. TREC images were acquired with magnetically oscillating AFM tips functionalized with a recombinant VE-cadherin-Fc cis-dimer. The recognition images revealed single molecular binding sites and prominent, irregularly shaped "dark" spots (domains) with sizes ranging from 10 to 100 nm. These domains arose from a decrease of the oscillation amplitude during specific binding between active VE-cadherin cis-dimers. The VE-cadherin clusters were subsequently assigned to topography features. TREC represents an exquisite method to quickly obtain the local distribution of receptors on cellular surface with an unprecedented lateral resolution of 5 nm.
Key Words:
VE-cadherin, endothelial cells, force microscopy, molecular recognition, recognition imaging, single molecule
