QD-based biosensors for protein assembly and mechanosensing

Understanding the mechanisms of assembly and disassembly of macromolecular structures in cells relies on solving biomolecular interactions. However, those interactions often remain unclear because tools to track molecular dynamics are not sufficiently resolved in time or space. In this study, we present a straightforward method for resolving inter- and intra-molecular interactions in the adhesive machinery, using Quantum Dot based FRET nanosensors. First, we measured the interaction between Talin, a key protein responsible for force transmission in focal adhesions, and the membrane. We quantified the distances separating Talin and the membrane in three Talin variants and predict their conformations using AlphaFold. Secondly, we investigated the mechanosensing capabilities of Talin. Sensitive unfolding mechanism of the protein, initiated by cytoskeleton contraction, was measured with nanometer precision. Thus, for the first time, biosensors enabled the observation of a 2 nm extension of Talin as a mechanosensitive response to actin-myosin contraction.