Dynamic architecture of microtubule networks

摘要 微管是一种动态的生物聚合物，是细胞内主要的运输通道。依赖MT 运输对于所有类型的细胞的生理来说都是至关重要的，而MT网络的干扰是许多人的基础 疾病，从神经退化到癌症。我的实验室研究MT网络的全球机制 完美地归因于特定的细胞功能。在很大程度上定义了MT网络组织 由新的MT启动增长的站点：MT组织中心(MTOC)。MT架构也是 受现有MTS局部稳定/解体和滑动的影响。此外，单个MT的亲和力 TO分子马达可以被选择性地调制，以提供细胞内运输的微调。虽然很多人 机制根据特定的小区功能定制MT组织，MT网络也可以动态响应 根据信令输入和生理上下文进行控制。MT网络的分子和空间调控 其中MTS的功能专门化还没有得到很好的理解。我的研究计划的长期目标 将在很大程度上由MIRA推动，包括定义：如何构建相间MT网络以及 调节；根据特定细胞需求定制MT几何构型的特定机制；分子和细胞 分化与分化过程中调节MT网络重建的生物学机制 生理输入；不同几何结构的MT网络如何协同工作，但交换功能 在不断变化的信令条件下的负载；以及MT与其他 构建细胞内空间的细胞系统。为了实现这些全球性和互动性的目标，我们发布了 MT架构组织中的许多中心发现(表征高尔基派生的MT网络 (GDMTs)；CLAP蛋白对MT+端结合复合体的变构调节；代谢调节 胰岛β细胞正常分泌胰岛素的MT网络)，以及胞浆结构中MT的功能(高尔基体 组装和完整性；c-Src运输；侵袭性肌动蛋白突起的动力学(足体)。在下一个 五年来，我将在我的程序现存的三个大方向上扩展机械和功能方面的洞察力 NIGMS支持的研究。(I)关于高尔基建筑群作为另一种MTOC，我们将确定 GDMT成核的空间模式、极化GDMT阵列是如何组织的，以及 高尔基体的MTOC功能如何受钙信号和分化信号的调节。(Ii)关于角色 对于MT网络结构中的MT结合蛋白，我们将确定MT调节器CLAP的类似物如何发挥作用 肿瘤抑制基因RASSF1A的特定功能和MT依赖功能。(三)探索如何 MT网络提供细胞质内的结构和功能组织，我们将剖析 定位高尔基体的微管蛋白和分子马达翻译后修饰的相互作用 在活动细胞中的细胞周期阶段之间的转换。

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.