Spatial Organization of Cytoskeletal Asymmetry

描述(由申请人提供)：微管(MT)属性在看似统一的MT网络中变化，并且具有相似属性的MT包括功能专门化的子集。在当前的资助期，我们已经确定了一个独特的MT亚群，它在高尔基体膜上成核(高尔基体源MT)。与放射状排列的中心体MT不同，高尔基体衍生的MT阵列本质上是不对称的，对于运动细胞的极性是必不可少的。我们先前和初步的数据表明高尔基体来源的MTS具有独特的功能。由于这些MT与高尔基体膜紧密结合，对于高尔基体的组装、维护和定位是不可或缺的。尽管高尔基体在生命周期和所有细胞的基本行为中的维持和重组具有明显的本质，但人们对协调其动态、时间调节功能的细胞内结构机制知之甚少。我们的研究解决的主要差距包括：如何跟踪小泡进出高尔基体，如何在高尔基体组装过程中确保堆叠对齐，以及它们如何在有丝分裂开始时及时重新定位。我们的初步和已发表的数据表明，高尔基体衍生的MT是这些精确协调过程的架构基础。我们推测，高尔基体来源的MT的独特位置及其负端在高尔基膜上，以及它们与MT结合蛋白环的特异性结合，从而对不同的分子马达进行不同的调节，这是MT亚群功能特异性的基础。这项提议的目的是确定高尔基体源MTS独特功能的空间和分子机制。因此，该提案针对的是机械细胞生物学的一个高影响力的基本领域。我们的具体目标是：1.测试高尔基体源MTS驱动的囊泡传递是否对高尔基体稳态至关重要2.确定高尔基体细胞分裂前的重新定位是否由高尔基体源MTS完成3.确定高尔基体源MT支持高效高尔基体堆叠融合的机制

DESCRIPTION (provided by applicant): Microtubule (MT) properties vary within seemingly uniform MT network, and MTs with similar properties comprise functionally specialized subsets. In the current funding period, we have characterized a distinct MT subset that nucleates at the Golgi membrane (Golgi-derived MTs). In contrast to the radially organized centrosomal MTs, Golgi-derived MT array is intrinsically asymmetric and is essential for polarity of motile cells. Our previous and preliminary data indicate that Golgi-derived MTs bear unique functions. Being closely associated with the Golgi membrane, these MTs are indispensable for Golgi complex assembly, maintenance and positioning. Despite the obvious essential nature of the maintenance and reorganization of the Golgi in the life cycle and basic behavior of all cells, there is a poor understanding of the intracellular architectural mechanisms that orchestrate its dynamic, temporally regulated functions. Major gaps addressed by our study include: how vesicles are tracked to/from the Golgi, how stack alignment is ensured during Golgi complex assembly, and how they are timely relocated at mitotic onset. Our preliminary and published data indicate that Golgi-derived MTs act as the architectural basis of these precisely coordinated processes. We hypothesize that distinct location of Golgi-derived MTs with their minus ends at the Golgi membrane and their specific association with a MT-binding protein CLASP, which differentially regulates distinct molecular motors, underlies functional specificity of this MT subset. The goal of this proposal is to determine the spatial and molecular mechanisms underlying the unique functions of Golgi-derived MTs. The proposal thus targets a high- impact, fundamental area of mechanistic cell biology. Our specific aims are: 1. Test whether vesicle delivery driven by Golgi-derived MTs is critical for Golgi homeostasis 2. Determine whether Golgi repositioning prior to cell division is accomplished by Golgi-derived MTs 3. Determine the mechanism whereby Golgi-derived MTs support efficient Golgi stack fusion