Quantum Dot-based biosensors for protein assembly and mechanosensing

Understanding the mechanisms of assembly and disassembly of macromolecular structures in cells relies on solving biomolecular interacFons. However, those interacFons o_en remain unclear because tools to track molecular dynamics are not sufficiently resolved in Fme or space. In this study, we present a straighaorward method for resolving inter- and intra- molecular interacFons in the adhesive machinery, using Quantum Dot based Förster Resonance Energy Transfer (FRET) nanosensors. IniFally, we measured the interacFon between Talin, a crucial protein responsible for force transmission in focal adhesions, and the membrane on which it assembles. We quanFfied the distances separaFng Talin and the membrane in three Talin molecular variants. Secondly, we invesFgated the mechanosensing capabiliFes of Talin, which means its unfolding due to mechanical stretching iniFated by cytoskeleton contracFon. For the first Fme, quantum dot-based nanosensors have enabled the quanFficaFon of mechanosensing, using the example of Talin behavior as a consequence of cytoskeletal tension. SensiFve unfolding mechanism of the protein and its assembling to the membrane were measured with sub-nanometer accuracy.