Allostery in myosins studied at the molecular level

在分子水平上研究肌球蛋白的变构

• 批准号: 7684659
• 负责人: Ronald S Rock
• 金额: $ 27.56万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-25 至 2011-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7684659
• 关键词: ATP Hydrolysis; Actins; Address; Amaze; Area; Behavior; Binding; Biochemical; Biological Assay; Biology; Cell Adhesion; Cell Division Process; Cell division; Cell physiology; Cells; Cellular Structures; Chemicals; Cilia; Communication; Coupled; Coupling; Crowding; Cytoskeletal Filaments; Cytoskeleton; Destinations; Development; Diffusion; Disease; Dynein ATPase; Environment; Eukaryotic Cell; Family; Filament; Filopodia; Free Energy; Generations; Goals; Hair Cells; Head; In Vitro; Individual; Inherited; Kinesin; Kinetics; Length; Life; Maintenance; Measurement; Measures; Mechanics; Mediator of activation protein; Methods; Microfilaments; Modeling; Molecular; Molecular Genetics; Molecular Machines; Motor; Motor Activity; Movement; Muscle Contraction; Myosin ATPase; Myosin Type V; Nature; Organism; Pattern; Proteins; Research; Research Personnel; Role; Running; Sensory Hair; Shapes; Signal Transduction; Surface; System; Time; Tissues; Travel; Walking; Work; Wound Healing; analog; cell motility; deafness; dimer; in vivo; myosin VI; nanometer; novel; programs; segregation; single molecule; trafficking

DESCRIPTION (provided by applicant): In the crowded environment of a typical eukaryotic cell, any object larger than 50 nm is effectively immobile and cannot rely on diffusion to arrive at its destination. As a result, myosin motors evolved to generate force for the transport of cargoes, cell motility, and cell division, processes that are critical for life itself. These motors convert chemical free energy by changing shape in a controlled manner while bound to actin filaments. A fundamental feature of all motor proteins is that their movements are carefully coordinated, so that the motor travels through a specific sequence of coupled biochemical and mechanical states. The nature of this coordination remains obscure, but it is clearly essential for proper motor function. The recent recognition that each myosin class has evolved specific structural and kinetic features allows for the comparison of different coordination mechanisms across the myosin super family. These individual adaptations may now be characterized by a host of advanced motility assays. The work proposed here will determine the allosteric coordination mechanisms using new single-molecule manipulations to alter the intramolecular strain felt by the motor. The role of the motor track in transmitting strain will be established, by mechanically altering the actin filament geometry. In addition, communication mechanisms will be identified for myosin V and myosin VI through load dependent stepping measurements under conditions where the two heads of the motor are uncoupled. These mechanisms will be contrasted with those for myosin X, a motor with unusual in vivo motility that suggests a novel form of strain sensing. The long term goal of this research is to reveal how motors, and systems of motors, have been optimized for their cellular trafficking tasks. Myosin motility is required for various normal and pathological cell functions, including development of polarized cellular structures, formation of cellular adhesions and tissue development, wound healing, intracellular trafficking, and cell division. This research will address critical questions about the underlying biology behind motor-related disease, including, among others, several forms of inherited deafness related to the proper development and maintenance of stereo cilia in sensory hair cells.

描述（由申请人提供）：在典型的真核生物单元的拥挤环境中，大于50 nm的任何物体有效地固定，并且不能依靠扩散来到达其目的地。结果，肌球蛋白电动机进化为产生对生命本身至关重要的货物，细胞运动和细胞分裂的运输的力。这些电动机通过以受控的方式改变形状，同时与肌动蛋白丝的形状改变形状。所有运动蛋白的基本特征是它们的运动是仔细协调的，因此电动机通过特定的生化和机械状态的特定序列传播。这种协调的性质仍然晦涩难懂，但对于适当的运动功能显然至关重要。最近认识到，每个肌球蛋白类别都会发展出特定的结构和动力学特征，可以比较整个肌球蛋白超级家族的不同配位机制。这些个体的适应现在可以以许多高级运动分析为特征。这里提出的工作将使用新的单分子操纵来确定变构配位机制，以改变电动机的分子内应变。通过机械改变肌动蛋白丝几何形状，将确定电动轨道在传输应变中的作用。此外，在电动机的两个头部未偶联的条件下，将通过载荷依赖的垫脚测量来确定肌球蛋白V和肌球蛋白VI的通信机制。这些机制将与肌球蛋白X的机制形成鲜明对比，肌球蛋白X是一种不寻常的体内运动的电动机，暗示了一种新型的应变感应形式。这项研究的长期目标是揭示电动机和电动机系统如何针对其细胞运输任务进行优化。各种正常和病理细胞功能需要肌球蛋白运动，包括偏振细胞结构的发展，细胞粘附和组织发育的形成，伤口愈合，细胞内运输和细胞分裂。这项研究将解决有关与运动相关疾病背后的潜在生物学的关键问题，其中包括与感觉毛细胞中立体声纤毛的适当发展和维持有关的几种遗传性耳聋。