Dynamic architecture of microtubule networks

摘要 微管 (MT) 是动态生物聚合物，是细胞中的主要运输高速公路。依赖MT 运输对于所有细胞类型的生理学至关重要，MT 网络的紊乱是许多人类疾病的基础 疾病，从神经退行性疾病到癌症。我的实验室研究 MT 网络的全局机制 旨在完美地归因于特定的细胞功能。很大程度上，定义了MT网络组织 由新 MT 开始生长的地点：MT 组织中心 (MTOC)。 MT架构也是 受现有 MT 局部稳定/拆卸和滑动的影响。此外，各个 MT 的亲和力 可以选择性地调节分子马达以提供细胞内运输的微调。虽然很多 机制根据特定小区功能定制 MT 组织，MT 网络也可以动态响应 根据信号输入和生理环境。 MT网络的分子和空间调控 其中 MT 的功能专业化尚未得到很好的理解。我的研究计划的长期目标 MIRA 将极大地促进这一点，其中包括定义：如何构建相间 MT 网络以及 受监管；根据特定细胞需求定制 MT 几何结构的特定机制；分子和细胞 分化和不同阶段调节 MT 网络重建的生物学机制 生理输入；具有不同几何形状的 MT 网络如何协同工作，同时切换功能 变化的信号条件下的负载；以及 MT 与其他人协作的方法 细胞系统构建细胞内空间。为了实现这些全球性和互动性的目标，我们发布了 机器翻译架构组织中的众多核心发现（表征高尔基衍生的机器翻译网络 （GDMT）； CLASP蛋白对MT正端结合复合物的变构调节；以及代谢调节 MT 网络（用于从 β 细胞正确分泌胰岛素），以及细胞质结构（高尔基体）中的 MT 功能 装配和完整性； c-Src运输；和侵入性肌动蛋白突起（足小体）的动力学）。在接下来的 五年内，我将在我的项目现有的三个主要方向上扩展机械和功能的洞察力 NIGMS 支持的研究。 (I) 将高尔基复合体作为替代 MTOC，我们将确定什么 GDMT 成核空间模式的机制、极化 GDMT 阵列的组织方式以及 高尔基体的 MTOC 功能如何通过钙信号传导和分化线索进行调节。 （二）关于角色 MT 网络架构中的 MT 结合蛋白，我们将确定 MT 调节器 CLASP 的旁系同源物如何发挥作用 特定功能并揭示肿瘤抑制因子 RASSF1A 的 MT 依赖性功能。 （三）探索如何 MT 网络提供了细胞质内的架构和功能组织，我们将剖析 微管蛋白和分子马达翻译后修饰的相互作用，定位高尔基体，同时 运动细胞的细胞周期阶段之间的转变。

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.