Regensburg 2007 – scientific programme

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BP: Fachverband Biologische Physik

BP 16: Poster Session I

BP 16.44: Poster

Tuesday, March 27, 2007, 17:00–19:30, Poster D

FRAP-Analysis of Protein Exchange Dynamics in Focal Adhesion Sites — •Christoph Möhl, Simone Born, Claudia Schäfer, Bernd Hoffmann, and Rudolf Merkel — Research Center Jülich GmbH, 52425 Jülich, Germany

Cell adhesion is an essential process for tissue integrity and cell movement. The adhesion process itself depends on clustered protein complexes called focal adhesion sites. These adhesion sites form a connection between the extracellular matrix and the actin cytoskeleton. Focal adhesions are characterized by a specific set of proteins such as integrins, regulatory kinases or proteins like vinculin, zyxin and VASP, bridging the integrins to actin fibers. In addition, focal adhesion sites can adapt in size and shape to cellular growth conditions. Thus, formation and release of focal adhesion sites are highly dynamic processes in moving cells but barely detectable when a cell is stationary. If various proteins additionally exchange in stable adhesion sites, and if such putative protein exchange dynamics goes along with the variable formation dynamics of whole adhesion sites is barely known.

Here, we present the analysis of protein exchange kinetics in focal adhesion sites of migrating and stationary cells by fluorescence recovery after photobleaching (FRAP). Experiments were performed with the GFP-labelled adhesion proteins vinculin, zyxin and VASP. The fluorescent label allowed the photobleaching of these proteins at distinct sites using a laser. By measuring the fluorescence recovery in the bleached area over time, we were able to examine significant differences between stable and dynamic adhesion sites.