Dynamic architecture of microtubule networks

摘要 微管（MT）是动态的生物聚合物，其充当细胞中的主要运输公路。MT依赖性 运输对于所有细胞类型的生理学是至关重要的，并且MT网络的干扰是许多人类疾病的基础。 从神经退化到癌症。我的实验室研究全球机制， 是为了完美地赋予特定的细胞功能而构建的。在很大程度上，MT网络组织被定义为 由新的MT开始增长的地点：MT组织中心（MTOC）。MT架构也是 受现有MT的局部稳定/拆卸和滑动的影响。此外，单个MT的亲和力 可以选择性地调节分子马达以提供细胞内转运的微调。虽然许多 机制使MT组织适合于特定的小区功能，MT网络也可以动态地响应 根据信号输入和生理背景。MT网络的分子和空间调控 和其中MT的功能专业化还没有很好地理解。我的研究项目的长期目标 将由MIRA提供巨大的便利，并包括定义：如何建立相间MT网络， 调节;特定机制定制MT几何结构以满足特定细胞需求;分子和细胞 分化和分化过程中MT网络重建的生物学机制 生理输入;具有不同几何结构的MT网络如何协同作用，但功能切换 在变化的信令条件下的负载;以及MT与其他MT协作的方法。 细胞系统来构建细胞内空间。为了实现这些全球性的互动目标，我们发布了 MT架构组织中的许多核心发现（表征高尔基衍生的MT网络 （GDMTs）; CLASP蛋白对MT+末端结合复合物的变构调节;以及代谢调节 从β细胞适当分泌胰岛素的MT网络），以及MT在细胞质结构（高尔基体）中的功能 组装和完整性; c-Src转运;以及侵入性肌动蛋白突起（podosomes）的动力学）。未来 五年后，我将在我的计划的现存的三个广泛的方向扩展机械和功能的见解 NIGMS支持的研究。(I)关于高尔基复合体作为替代MTOC，我们将确定 GDMT成核的空间模式，极化GDMT阵列如何组织， 高尔基体的MTOC功能是如何通过钙信号和分化信号调节的。(II)角色方面的 MT结合蛋白的MT网络架构，我们将确定如何旁系同源的MT调节CLASP发挥 特异性功能，并揭示肿瘤抑制因子RASSF1A的MT依赖性功能。(III)探索如何 MT网络提供了细胞质内的结构和功能组织，我们将剖析 微管蛋白的翻译后修饰和定位高尔基体的分子马达的相互作用， 在运动细胞中细胞周期阶段之间的过渡。

Abstract Microtubules (MTs) are dynamic biopolymers, which serve as major trafficking highways in cells. MT-dependent transport is critical for physiology of all cell types, and disturbance of MT networks underlies many human diseases, from neurodegeneration to cancer. My laboratory studies global mechanisms whereby MT networks are built to perfectly attribute to specific cellular functions. To a large extent, MT network organization is defined by the sites from where new MTs initiate growth: the MT-organizing centers (MTOCs). MT architecture is also influenced by local stabilization/disassembly and sliding of existing MTs. Furthermore, affinity of individual MTs to molecular motors can be selectively modulated to provide fine-tuning of intracellular transport. While many mechanisms tailor MT organization to specific cell functions, the MT network can also respond dynamically according to signaling inputs and the physiological context. Molecular and spatial regulation of the MT network and functional specialization of MTs therein are not well understood. My research program’s long-term goals will be hugely facilitated by the MIRA, and include defining: how interphase MT networks are built and regulated; specific mechanisms tailoring MT geometry to specific cellular needs; molecular and cell biological mechanisms modulating MT network rebuilding during differentiation and different physiological inputs; how MT networks with different geometries act in concert, yet switch functional loads under changing signaling conditions; and, the methods whereby MTs collaborate with other cellular systems to build intracellular space. Toward these global and interactive goals, we have published numerous central discoveries in MT architecture organization (characterizing Golgi-derived MT networks (GDMTs); the allosteric regulation of MT plus-end binding complex by CLASP proteins; and, metabolic regulation of MT network for proper insulin secretion from beta cells), and MT function in cytoplasmic architecture (Golgi assembly and integrity; c-Src transport; and dynamics of invasive actin protrusions, the podosomes). In the next five years, I will extend the mechanistic and functional insight in three broad directions of my program’s extant NIGMS-supported research. (I) Regarding the Golgi complex as an alternative MTOC, we will determine what mechanisms underlie the spatial pattern of GDMT nucleation, how polarized GDMT arrays are organized, and how MTOC functions of the Golgi are tuned by calcium signaling and differentiation cues. (II) Regarding the roles of MT-binding proteins in MT network architecture, we will determine how paralogs of MT regulator CLASP exert specific functions and uncover MT-dependent functions of the tumor suppressor RASSF1A. (III) Exploring how the MT network provides architecture and functional organization within the cytoplasm, we will dissect the interplay of post-translational modifications of tubulin and molecular motors that position the Golgi while transitioning between cell-cycle stages in motile cells.