Brownian search-and-catch mechanism for myosin-VI steps

The cargo transporter myosin-VI processively walks along actin filaments using its two heads. Here we use single-molecule nanometry to show that the strong binding by myosin heads to actin is greatly accelerated (similar to 30-fold) when backward strain is applied to weakly bound heads during the actin search. We propose that the myosin head searches for the forward actin target by Brownian motion and catches the actin in a strain-dependent manner.