Allostery in myosins studied at the molecular level

在分子水平上研究肌球蛋白的变构

基本信息

批准号：
7492105
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
项目类别：
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/7492105
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 Class Communication Condition 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 Range Rate 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

项目摘要

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）：在典型真核细胞的拥挤环境中，任何大于 50 nm 的物体实际上都是固定不动的，并且不能依靠扩散到达目的地。结果，肌球蛋白马达进化为产生力量来运输货物、细胞运动和细胞分裂，这些过程对生命本身至关重要。这些马达在与肌动蛋白丝结合的同时，通过以受控方式改变形状来转换化学自由能。所有运动蛋白的一个基本特征是它们的运动经过仔细协调，以便运动通过耦合的生化和机械状态的特定序列。这种协调的本质仍然不清楚，但它显然对于正确的运动功能至关重要。最近认识到每个肌球蛋白类别都进化出了特定的结构和动力学特征，从而可以比较肌球蛋白超家族的不同协调机制。这些个体适应现在可以通过一系列先进的运动测定来表征。这里提出的工作将使用新的单分子操作来确定变构协调机制，以改变电机感受到的分子内应变。通过机械改变肌动蛋白丝的几何形状，将确定运动轨道在传递应变中的作用。此外，在电机两个头未耦合的情况下，将通过负载相关的步进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 的机制形成对比，肌球蛋白 X 是一种具有不寻常的体内运动性的马达，表明了一种新型的应变传感。这项研究的长期目标是揭示电机和电机系统如何针对其细胞运输任务进行优化。肌球蛋白运动是各种正常和病理细胞功能所必需的，包括极化细胞结构的发育、细胞粘附的形成和组织发育、伤口愈合、细胞内运输和细胞分裂。这项研究将解决有关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纤毛的正确发育和维持相关的几种形式的遗传性耳聋。