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Search for new biological motors

寻找新的生物马达

基本信息

批准号：
09279102
负责人：
KAMIYA Ritsu
金额：
$ 107.52万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research on Priority Areas (A)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 2000
项目状态：
已结题

项目摘要

This research was aimed at elucidating the characteristic functional properties of various biological motor proteins, focusing on axonemal dyneins and plant myosins. Axonemal dyneins, the motor proteins that produce ciliary and flagellar beating, exist as 11 different species arranged along the outer doublet microtubules. Despite extensive studies, their functional characteristics have not been established. In the present study, Chlamydomonas mutants lacking specific species of inner arm dynein were isolated, yielding important clues as to the function and localization of inner-arm dynein subspecies. In addition, through analyses of proteins interacting with various dyneins, a new protein complex was found that anchor dyneins to the microtubule. Finally, force production by a single dynein molecule was measured in vitro, in the first single-molecule measurement on dynein. A new feature of dynein force production was discovered ; dynein changes its force production properties depending on the concentration of ATP. Plant myosin studies identified two new kinds of myosins in cultured tobacco cells. One was found to bind calmodulin. Interestingly, this myosin decreased its motile activity at increased calcium concentrations ; this is one of the first examples that clearly show an inhibitory effect of calcium ion on plant myosin. Also, the gene of Chara (an alga) myosin, a motor protein known to produce an extremely rapid movement, was cloned and the protein was successfully expressed in cultured cells as well as in cellular slime mold. An unexpected finding was that a chimeric construct, with the head motor domain derived from Chara and the tail region from slime mold, displayed much slower speed than native Chara myosin. Therefore, the reason why Chara myosin produces very rapid movement has remained a puzzle.

本研究旨在阐明各种生物马达蛋白的特征功能特性，重点是轴丝动力蛋白和植物肌球蛋白。轴丝动力蛋白是产生纤毛和鞭毛搏动的马达蛋白，存在于沿着外部双线微管排列的11种不同种类。尽管进行了广泛的研究，但其功能特征尚未确定。在本研究中，衣原体突变体缺乏特定物种的内臂动力蛋白被隔离，产生重要的线索，内臂动力蛋白亚种的功能和定位。此外，通过对与各种动力蛋白相互作用的蛋白质的分析，发现了一种新的蛋白质复合物，它将动力蛋白锚在微管上。最后，在体外测量了单个动力蛋白分子的力产生，这是对动力蛋白的第一次单分子测量。动力蛋白力产生的一个新特征被发现;动力蛋白根据ATP的浓度改变其力产生特性。植物肌球蛋白研究在培养的烟草细胞中鉴定出两种新的肌球蛋白。一个被发现结合钙调素。有趣的是，这种肌球蛋白在钙浓度增加时运动活性降低;这是第一个明确显示钙离子对植物肌球蛋白抑制作用的例子之一。此外，克隆了轮藻肌球蛋白（一种已知产生极快运动的运动蛋白）的基因，并在培养细胞和细胞黏菌中成功表达了该蛋白。一个意想不到的发现是，嵌合构建体，与来自轮藻和粘菌的尾部区域的头部马达域，显示出比天然轮藻肌球蛋白慢得多的速度。因此，为什么轮藻肌球蛋白产生非常快速的运动仍然是一个谜。