Dynein-mediated cargo transport in vivo. A switch controls travel distance.
Dynein-mediated cargo transport in vivo. A switch controls travel distance.
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Dynein介导的体内货物运输。开关控制旅行距离。
DOI：
10.1083/jcb.148.5.945
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发表时间：
2000-03-06
影响因子：
7.8
通讯作者：
Wieschaus, E F
中科院分区：
文献类型：
--
作者：
Gross, S P;Welte, M A;Block, S M;Wieschaus, E F
胞浆动力蛋白是一种以微管为基础的马达，具有多种细胞功能。在这里，我们使用动力蛋白重链基因的突变来损害马达的功能，并使用生物物理测量来证明细胞质动力蛋白是导致早期果蝇胚胎中双向运动的脂滴负端运动的原因。这一分析得出了单个细胞质动力蛋白在体内施加的力的估计(1.1pN)。它还使我们能够量化动力蛋白在体内介导的货物运动，为研究动力蛋白的活动是如何控制的提供了一个框架。我们确定了三种不同的运动状态，它们的一般特征也是正端运动的特征。这些状态在不同的发育阶段被保存下来。我们先前曾提供证据表明，对于每个移动方向，单个液滴都是由同一类型的多个电机移动的(Welte等人)。1998年)。根据细胞质动力蛋白处理能力的体外估计，多个马达的液滴旅行距离(运行)比预期的要短得多。因此，我们建议存在一个在马达从微管上掉下来之前结束运行的过程。我们发现，这个过程以每单位距离恒定的概率作用，并且通常在行进方向上与开关耦合。一个具有相似性质的过程支配着正末端运动，它的调节控制着运输的净方向。
Cytoplasmic dynein is a microtubule-based motor with diverse cellular roles. Here, we use mutations in the dynein heavy chain gene to impair the motor's function, and employ biophysical measurements to demonstrate that cytoplasmic dynein is responsible for the minus end motion of bidirectionally moving lipid droplets in early Drosophila embryos. This analysis yields an estimate for the force that a single cytoplasmic dynein exerts in vivo (1.1 pN). It also allows us to quantitate dynein-mediated cargo motion in vivo, providing a framework for investigating how dynein's activity is controlled. We identify three distinct travel states whose general features also characterize plus end motion. These states are preserved in different developmental stages. We had previously provided evidence that for each travel direction, single droplets are moved by multiple motors of the same type (Welte et al. 1998). Droplet travel distances (runs) are much shorter than expected for multiple motors based on in vitro estimates of cytoplasmic dynein processivity. Therefore, we propose the existence of a process that ends runs before the motors fall off the microtubules. We find that this process acts with a constant probability per unit distance, and is typically coupled to a switch in travel direction. A process with similar properties governs plus end motion, and its regulation controls the net direction of transport.