MPS seminar Christine Selhuber-Unkel

Adhesion clusters studied at the nanometer scale

Many phenomena of the intra- and extracellular organization of an organism are related to the mechanochemical coupling between cells and the extracellular space. Often, this coupling is maintained by hierarchically organized protein clusters, the focal contacts. For a quantitative understanding of a focal contact, biofunctional nanopatterns can be employed where adhesion ligands are positioned in a quasi-hexagonal lattice. Recent cell culture experiments have revealed that the distance between nanometer-sized adhesion ligand patches strongly affects the formation of focal contacts. To quantify focal contact formation for different adhesion ligand spacings, we have studied cell adhesion forces with an atomic force microscope. The experiments have demonstrated that an adhesion ligand spacing of 70 nm and more prevents the cooperative formation of early adhesion clusters during the first five minutes of cell-substrate contact. In long-term adhesion studies, after several hours of cell adhesion, focal contact formation cooperatively increases the local adhesion strength. Our results demonstrate how cells amplify small molecular differences in their adhesive environment to large differences in cell adhesion strength.

 

Christine Selhuber-Unkel

Niels Bohr Institute / Optical Tweezers Group

 

Monday 24 November 2008, 3 PM

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