Integration and control of molecular motors

描述(由申请人提供)： 靶向运输细胞成分到特定位置是每种真核细胞类型正常活动和生长所必需的功能。这三个运动家族，肌球蛋白、动力蛋白和运动蛋白，共同引导货物沿着微管和肌动蛋白细胞骨架。虽然需要多个马达来实现双向运动，并在这些细胞骨架轨迹之间切换，但它们之间的协调和竞争还不清楚。许多分子马达受钙离子、磷酸化或由蛋白质支架募集到其作用部位的调节。以马达蛋白为靶点的结构域，组装马达和货物之间特定联系的支架，以及大分子马达和脂类之间的结合化学，是主要的悬而未决的问题。为早期研究开发的新的生物物理、分子和细胞生物学技术为理解靶向细胞内运输提供了令人兴奋的机会。在这个项目中，基于肌动蛋白的马达，肌球蛋白I，肌球蛋白V和肌球蛋白VI，以及基于微管的马达，细胞质动力蛋白，及其附属蛋白复合体，动力肌动蛋白，将通过一系列最先进的方法进行深入的研究。单分子荧光偏振、纳米分辨荧光团定位、红外光学陷阱、快速生化反应动力学、纳秒时间分辨荧光各向异性、动态光散射、遗传操作以及详细的电子和原子力显微镜将在合作研究中应用，以了解分子马达的单独机制及其相互作用。要了解每个细胞的组装过程，包括肌肉肌节和细胞骨架，需要深入研究一些不同的马达蛋白的功能。由于细胞的增殖、组装、蛋白质表达、运动、能量代谢、防御、营养和分泌都涉及这种局部的运动驱动复合体，因此理解靶向细胞内转运的机制和控制的影响遍及所有细胞生物学。肿瘤的侵袭和转移、神经元和肌肉的发育、宿主防御的病原体攻击和许多其他系统都广泛使用相同的分子马达。因此，详细了解这些蛋白的功能和相互作用在人类疾病和治疗中具有特定和广泛的意义。我们将发现马达蛋白、动力蛋白和非传统肌球蛋白是如何在兄弟姐妹关系中单独发挥作用的。

DESCRIPTION (provided by applicant): Targeted transport of cellular constituents to specific locations is an essential function for normal activity and growth in every eukaryotic cell type. The three motor families, myosins, dyneins and kinesins, cooperate in directing cargoes along microtubules and the actin cytoskeleton. Although multiple motors are required to confer bidirectional motion and to switch between these cytoskeletal tracks, the coordination and competition between them is not understood. Many of the molecular motors are regulated by Ca 2+, phosphorylation, or recruitment to their sites of action by protein scaffolds. The domains that target the motor proteins, the scaffolds that assemble the specific linkages between motors and cargoes, and the chemistry of association between macromolecular motors and lipids are major open questions. Novel biophysical, molecular, and cell biological techniques developed for earlier studies open exciting opportunities for understanding targeted intracellular transport. In this program project, the actin-based motors, myosin I, myosin V and myosin VI, and the microtubule-based motor, cytoplasmic dynein, and its accessory protein complex, dynactin, will be studied intensively by a battery of state-of-the-art approaches. Single-molecule fluorescence polarization, nanometer-resolved fluorophore localization, infrared optical traps, rapid biochemical reaction kinetics, nanosecond time-resolved fluorescence anisotropy, dynamic light scattering, genetic manipulations, and detailed electron and atomic force microscopy will be applied in collaborative studies to understand the individual mechanisms of molecular motors and their mutual interactions. An understanding of the assembly process of every cell, including the muscle sarcomere and cytoskeleton, will require an in-depth study of the function of a number of different motor proteins. As cell proliferation, assembly, protein expression, motility, energy metabolism, defense, nourishment, and secretion all involve such localized motor-driven complexes, the impact of understanding the mechanisms and control of targeted intracellular transport spreads across all of cell biology. Cancer invasion and metastasis, neuronal and muscle development, pathogen attack by host defenses and many other systems make extensive use of the same molecular motors. Thus, detailed understanding of the function and interaction of these proteins have specific and broad-reaching implications in human disease and treatment. We will discover how motor proteins, dynein and unconventional myosins work individually and in brother/sisterhood.