Single Molecule Biophysics

Resolving the interactions of cadherin, a key molecule in cell-cell adhesion.

Cadherins play a key role in the organization of cells and in maintaining the structural integrity of tissues . Disruption of adhesion is common in metastatic cancers. Despite detailed studies of cadherin-mediated adhesion, the molecular interactions that are at the core of cadherin binding are poorly understood.

We have developed a series of single molecule in vitro assays to directly detect cadherin binding conformations, identify the molecular contacts involved in adhesion, and measure cooperativity in cadherin binding. Using single molecule Fluorescence Resonance Energy Transfer (FRET) and single molecule force measurements with the Atomic Force Microscope (AFM) we have resolved conflicting data on cadherin binding states, and provided quantitative evidence for cooperativity in cadherin adhesion. We are currently using similar single molecule approaches to resolve the role of key amino acids in cadherin interactions.

Left: Single molecule fluorescence time trace showing FRET from a cadherin transdimer.
Right: The unbinding force curve of a single cadherin molecule measured with an AFM