Reddy A S
Department of Biology and Program in Cell and Molecular Biology, Colorado State University, Fort Collins 80523, USA.
Int Rev Cytol. 2001;204:97-178. doi: 10.1016/s0074-7696(01)04004-9.
Molecular motors that hydrolyze ATP and use the derived energy to generate force are involved in a variety of diverse cellular functions. Genetic, biochemical, and cellular localization data have implicated motors in a variety of functions such as vesicle and organelle transport, cytoskeleton dynamics, morphogenesis, polarized growth, cell movements, spindle formation, chromosome movement, nuclear fusion, and signal transduction. In non-plant systems three families of molecular motors (kinesins, dyneins, and myosins) have been well characterized. These motors use microtubules (in the case of kinesines and dyneins) or actin filaments (in the case of myosins) as tracks to transport cargo materials intracellularly. During the last decade tremendous progress has been made in understanding the structure and function of various motors in animals. These studies are yielding interesting insights into the functions of molecular motors and the origin of different families of motors. Furthermore, the paradigm that motors bind cargo and move along cytoskeletal tracks does not explain the functions of some of the motors. Relatively little is known about the molecular motors and their roles in plants. In recent years, by using biochemical, cell biological, molecular, and genetic approaches a few molecular motors have been isolated and characterized from plants. These studies indicate that some of the motors in plants have novel features and regulatory mechanisms. The role of molecular motors in plant cell division, cell expansion, cytoplasmic streaming, cell-to-cell communication, membrane trafficking, and morphogenesis is beginning to be understood. Analyses of the Arabidopsis genome sequence database (51% of genome) with conserved motor domains of kinesin and myosin families indicates the presence of a large number (about 40) of molecular motors and the functions of many of these motors remain to be discovered. It is likely that many more motors with novel regulatory mechanisms that perform plant-specific functions are yet to be discovered. Although the identification of motors in plants, especially in Arabidopsis, is progressing at a rapid pace because of the ongoing plant genome sequencing projects, only a few plant motors have been characterized in any detail. Elucidation of function and regulation of this multitude of motors in a given species is going to be a challenging and exciting area of research in plant cell biology. Structural features of some plant motors suggest calcium, through calmodulin, is likely to play a key role in regulating the function of both microtubule- and actin-based motors in plants.
能够水解ATP并利用所产生的能量来产生力的分子马达参与了多种不同的细胞功能。遗传学、生物化学及细胞定位数据表明，马达参与了诸如囊泡和细胞器运输、细胞骨架动力学、形态发生、极性生长、细胞运动、纺锤体形成、染色体运动、核融合及信号转导等多种功能。在非植物系统中，三类分子马达（驱动蛋白、动力蛋白和肌球蛋白）已得到充分表征。这些马达利用微管（驱动蛋白和动力蛋白的情况）或肌动蛋白丝（肌球蛋白的情况）作为轨道在细胞内运输货物。在过去十年中，在理解动物体内各种马达的结构和功能方面取得了巨大进展。这些研究为分子马达的功能及不同马达家族的起源提供了有趣的见解。此外，马达结合货物并沿细胞骨架轨道移动的模式并不能解释某些马达的功能。关于植物中的分子马达及其作用，人们了解得相对较少。近年来，通过使用生物化学、细胞生物学、分子生物学和遗传学方法，已从植物中分离并表征了一些分子马达。这些研究表明，植物中的一些马达具有新颖的特征和调控机制。分子马达在植物细胞分裂、细胞扩张、胞质环流、细胞间通讯、膜运输和形态发生中的作用正开始被人们所理解。利用驱动蛋白和肌球蛋白家族保守的马达结构域对拟南芥基因组序列数据库（占基因组的51%）进行分析表明，存在大量（约40个）分子马达，其中许多马达的功能仍有待发现。很可能还有更多具有新颖调控机制、执行植物特定功能的马达有待发现。尽管由于正在进行的植物基因组测序项目，植物中尤其是拟南芥中马达的鉴定进展迅速，但只有少数植物马达得到了详细表征。阐明给定物种中众多马达的功能和调控将是植物细胞生物学中一个具有挑战性且令人兴奋的研究领域。一些植物马达的结构特征表明，钙通过钙调蛋白可能在调节植物中基于微管和肌动蛋白的马达功能方面发挥关键作用。
