Spatial Organization of Cytoskeletal Asymmetry

描述（由申请人提供）：微管（MT）性质在看似均匀的MT网络中变化，具有相似性质的MT包括功能专门化的子集。在目前的资助期间，我们已经确定了一个独特的MT子集，在高尔基体膜（高尔基体衍生的MT）的核。与放射状排列的中心体MT相比，高尔基体衍生的MT阵列本质上是不对称的，并且对运动细胞的极性至关重要。 我们以前的和初步的数据表明，高尔基体衍生的MT承担独特的功能。这些MT与高尔基体膜紧密相连，是高尔基体组装、维持和定位所必需的。尽管高尔基体的维持和重组在所有细胞的生命周期和基本行为中具有明显的本质，但对协调其动态的、时间调节的功能的细胞内结构机制的理解却很差。我们的研究解决的主要差距包括：如何跟踪囊泡到/从高尔基体，如何确保堆栈对齐在高尔基复合体组装，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作为这些精确协调的过程的建筑基础。我们假设，不同的位置高尔基体衍生的MT与其负端在高尔基体膜和他们的特定关联与MT结合蛋白CLASP，差异调节不同的分子马达，这MT子集的功能特异性的基础。这个建议的目标是确定高尔基体衍生的MT的独特功能的空间和分子机制。因此，该提案的目标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.测试高尔基体衍生的MT驱动的囊泡递送是否对高尔基体稳态至关重要2。确定是否高尔基体重新定位细胞分裂前完成高尔基体衍生的MT 3。确定高尔基体衍生的MT支持有效高尔基体堆栈融合的机制

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