Abstract
The regulation of actin dynamics is essential for various cellular processes. Former evidence suggests a correlation between the function of non-conventional myosin motors and actin dynamics. We investigate the contribution of the catch-bond Myosin1b to actin dynamics using sliding motility assays. We observe that sliding on Myosin1b immobilized or bound to a fluid bilayer enhances actin depolymerization at the barbed end, while sliding on the weak catch-bond MyosinII has no effect. Our theoretical model supports that the catch-bond prolongs the attachment time of the motor at the barbed end due to the friction force exerted by the sliding filament; thereby this motor exerts a sufficient force on this end to promote depolymerization. This work reveals a non-conventional myosin motor as a new type of depolymerase.
Sentence summary Due to its catch bond, Myosin 1b depolymerizes sliding actin filaments at their barbed end by exerting a prolonged force.