Recreating biological phenomena in model systems with defined components and properties has proven to be a powerful means for dissecting molecular mechanisms. Our research is dedicated to the development of such model systems that allow the reconstitution, observation and physical manipulation of cellular processes down to the single molecule level. In particular, we apply micro- and nanostructured biointerfaces to gain a quantitative and mechanistic understanding of plasma membrane organization and associated cellular signaling processes, with a particular interest in the molecular mechanisms of T-cell signaling.
DNA origami as a tool to study cell surface receptor signaling
he nanoscale spatial organization of ligands and receptors is emerging as an important theme in regulating cell behavior. We have developed a cell-responsive biomimetic interface based on laterally mobile functionalized DNA origami platforms to probe the spatial requirements for receptor-mediated signaling. While fully responsive to dynamic receptor rearrangements on the cell surface upon ligand engagement, the biointerface allows the experimenter to adjust protein distances with nanoscale precision as a means to disturb signaling. We currently apply and refine our biointerface to identify and validate cell biological, biophysical and biochemical parameters underlying sensitized T-cell antigen detection.
Ligand-functionalized DNA origami platforms are attached via cholesterol-modified oligonucleotides to supported lipid bilayers, where they diffuse freely. The platforms set a minimum distance δ between neighboring ligands (e.g. pMHCs)as they cluster after T-cell receptor (TCR) engagement.
Protein micropatterning to study plasma membrane organization and function
It is inherently difficult to study the interactions of proteins and lipids in the plasma membrane of living cells. We have developed a protein micropatterning assay where we use microstructured surfaces to confine a protein of interest to specific areas in the cellular plasma membrane and monitor the interaction with other membrane constituents via single molecule microscopy. By doing so we can extract kinetic parameters of specific interactions but also study fundamental elements of plasma membrane organization.
a, Microstructuring of proteins in the live cell plasma membrane. b, Mammalian cell on a micropatterned surface; the patterned protein is labeled with mGFP. c, Monitoring the interaction of lipids with micropatterned proteins via single molecule tracking of lipids.