Activated nanoscale actin-binding domain motion in the catenin-cadherin complex revealed by neutron spin echo spectroscopy

Mechanical force affects fundamental processes in biology like cell adhesion, tissue morphogenesis, and tumorigenesis. The molecular mechanisms by which cells utilize their protein machineries to sense and transduce mechanical forces remain to be elucidated. This study describes the application of neutron spin echo spectroscopy to reveal the activation of nanoscale motions of the actin-binding domain in the cadherin-catenin complex. The activated domain motion and an ensemble of domain configurations adopted by the mechanosensory actin-binding domain suggest the formation of an entropic trap in the cadherin-catenin complex. We hypothesize that mechanical tension facilitates the reduction in entropy of a mechanosensitive protein and thereby focuses the configuration space to specific conformations that are competent to bind the moving actin microfilament.