Myosin VI is a molecular motor involved in intracellular vesicle transport and anchoring of organelles and cytoskeletal structures. To cary out its cellular functions myosin VI moves toward the pointed end of actin, backwards relative to all other characterized myosins. Myosin VI is also processive, meaning that it takes multiple steps along actin before releasing. In this respect, it is similar to some other classes of unconventional myosins (such as myosin V), but quite different from skeletal myosin II. Remarkably, myosin VI takes much larger steps than expected from a simple lever arm model. Such steps are highly irregular, with a broad distribution of step sizes. Recently, we have demonstrated that the proximal tail region of myosin VI can act as a flexible element that allows the two heads to separate along actin, and is responsible for the large step size of this myosin. This proximal tail region may in fact be a natively unfolded domain that can act as an entropic spring.
Copyright. All Rights Reserved.