Berezuk Matthew A, Schroer Trina A
Department of Biology, The Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA.
Traffic. 2007 Feb;8(2):124-9. doi: 10.1111/j.1600-0854.2006.00517.x. Epub 2006 Dec 20.
Kinesin-2 is a major microtubule-based motor in most cell types. Its in vitro motile properties have been analyzed extensively and been found to differ considerably from kinesin-1. Although recombinant kinesin-2 heterodimers exhibit processive movement, the processivity of the native kinesin-2 holoenzyme has never been evaluated. Kinesin-2 can interact with dynactin, a 'processivity factor' for cytoplasmic dynein, which may alter its motile properties. In this study, we analyze the in vitro motility of single native kinesin-2 molecules and determine the effects of dynactin on motor processivity. We find that individual native kinesin-2 molecules travel processively. Dynactin has no effect on velocity but significantly increases the run length of kinesin-2 movements. These results show that the interaction with dynactin has important functional consequences on the activity of the kinesin-2 motor.
驱动蛋白-2是大多数细胞类型中一种主要的基于微管的分子马达。其体外运动特性已得到广泛分析，并且发现与驱动蛋白-1有很大差异。尽管重组驱动蛋白-2异二聚体表现出持续运动，但天然驱动蛋白-2全酶的持续性从未被评估过。驱动蛋白-2可与动力蛋白激活蛋白相互作用，动力蛋白激活蛋白是胞质动力蛋白的一种“持续性因子”，这可能会改变其运动特性。在本研究中，我们分析了单个天然驱动蛋白-2分子的体外运动，并确定动力蛋白激活蛋白对分子马达持续性的影响。我们发现单个天然驱动蛋白-2分子能持续移动。动力蛋白激活蛋白对速度没有影响，但显著增加了驱动蛋白-2运动的行程长度。这些结果表明，与动力蛋白激活蛋白的相互作用对驱动蛋白-2分子马达的活性具有重要的功能影响。
