Force-dependent isomerization kinetics of a highly conserved proline switch modulates the mechanosensing region of filamin.

Biological processes in the cell are highly dynamic and complex, and their correct interplay is ensured by a multitude of regulatory mechanisms. Among these, proline isomerization acts as a molecular switch that toggles two protein conformations, and thus functions, over time. In mechanosensing, mechanical stress is transduced into chemical signals. The molecular mechanisms underlying this regulation are crucial for understanding cell behavior and development. However, only a few experimental techniques are capable of studying force at the molecular level. In this paper, we use single-molecule mechanical experiments to investigate how the force-sensing region of the cytoskeletal cross-linker filamin is modulated by a proline switch.