Determinants of processivity in the single-headed class IX myosins

肌球蛋白是一个大家族的各种机械酶，结合Factin和水解ATP产生机械力。不同的肌球蛋白分子在它们的运动特性上有很大的不同，如速度、力量、步长、方向、持续合成能力、与这些特性的轨迹和调节的相互作用。这些运动特性的差异使得肌球蛋白具有许多不同的细胞功能。IX类肌球蛋白在从肌动蛋白丝上解离之前，沿着沿着肌动蛋白丝连续移动，采取多个步骤。这是一个例外，因为它们是单头的，并且在ATP结合状态下花费相当长的时间，这是一种对其他肌球蛋白中的F-肌动蛋白具有弱亲和力的状态。我们希望阐明单头进行性运动的机制，并确定必要的调整，这些研究将导致更好地了解肌动蛋白为基础的分子马达，单电机的持续性和多域IX类肌球蛋白的细胞功能的一般机制，同时是小单体G蛋白Rho的负调节剂。

Myosins are a large family of diverse mechanoenzymes that bind to Factin and hydrolyse ATP to produce mechanical force. Different myosin molecules differ substantially in their motor properties such as speed, force, step size, direction, processivity, interplay with the track and regulation of these properties. These differences in motor properties allow myosins to adopt many different cellular functions. The class IX myosins move processively along actin filaments taking multiple steps before they dissociate from the actin filament. This is exceptional because they are single-headed and spend a considerable amount of time in the ATP-bound state that is a state with weak affinity for F-actin in other myosins. We hope to elucidate the mechanism of single-headed processive movement and to identify the necessary adaptations for it. These studies will lead to a better understanding of the general mechanisms of actin-based molecular motors, single motor processivity and the cellular functions of the multi-domain class IX myosins that are simultaneously negative regulators of the small monomeric G-protein Rho.