Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, 80523, USA.
Nat Commun. 2017 Dec 15;8(1):2151. doi: 10.1038/s41467-017-02004-2.
Cytoplasmic dynein is an enormous minus end-directed microtubule motor. Rather than existing as bare tracks, microtubules are bound by numerous microtubule-associated proteins (MAPs) that have the capacity to affect various cellular functions, including motor-mediated transport. One such MAP is She1, a dynein effector that polarizes dynein-mediated spindle movements in budding yeast. Here, we characterize the molecular basis by which She1 affects dynein, providing the first such insight into which a MAP can modulate motor motility. We find that She1 affects the ATPase rate, microtubule-binding affinity, and stepping behavior of dynein, and that microtubule binding by She1 is required for its effects on dynein motility. Moreover, we find that She1 directly contacts the microtubule-binding domain of dynein, and that their interaction is sensitive to the nucleotide-bound state of the motor. Our data support a model in which simultaneous interactions between the microtubule and dynein enables She1 to directly affect dynein motility.
细胞质动力蛋白是一种巨大的负端导向微管马达。微管不是简单地存在，而是被许多微管相关蛋白（MAPs）结合，这些 MAPs 具有影响各种细胞功能的能力，包括马达介导的运输。其中一种 MAP 是 She1，它是一种动力蛋白效应物，使芽殖酵母中的动力蛋白介导的纺锤体运动极化。在这里，我们描述了 She1 影响动力蛋白的分子基础，这是首次深入了解 MAP 如何调节运动蛋白的运动性。我们发现 She1 影响动力蛋白的 ATP 酶速率、微管结合亲和力和步进行为，并且 She1 对微管的结合对于其对动力蛋白运动性的影响是必需的。此外，我们发现 She1 直接与动力蛋白的微管结合域接触，并且它们的相互作用对马达核苷酸结合状态敏感。我们的数据支持这样一种模型，即微管和动力蛋白之间的同时相互作用使 She1 能够直接影响动力蛋白的运动性。
