Hensley Andrew M, Yildiz Ahmet
Physics Department, University of California, Berkeley, CA, USA.
Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA.
bioRxiv. 2025 Aug 31:2025.08.27.672644. doi: 10.1101/2025.08.27.672644.
Kinesin-1 is a robust motor that carries intracellular cargos towards the plus ends of microtubules. However, optical trapping studies reported that kinesin-1 is a slippery motor that quickly detaches from the microtubule, and multiple kinesins are incapable of teaming up to generate large collective forces. This may be due to the vertical (z) forces that the motor experiences in a single bead trapping assay, accelerating the detachment of the motor from a microtubule. Here, we substantially lowered the z-force by using a long DNA handle between the motor and the trapped bead and characterized the motility and force generation of single and multiple kinesin-1s. Contrary to previous views, we show that kinesin-1 is a robust motor that resists microtubule detachment before it reaches high hindering loads, but it quickly detaches under assisting loads even at low z-forces. We also demonstrate highly efficient collective force generation by multiple kinesin-1 motors. These results provide an explanation for how multiple kinesins team up to perform cellular functions that require higher forces than a single motor can bear.
驱动蛋白-1是一种强大的分子马达，它能将细胞内的货物向微管的正端运输。然而，光镊研究报告称，驱动蛋白-1是一种滑动性分子马达，会迅速从微管上脱离，而且多个驱动蛋白无法协同合作产生较大的集体力。这可能是由于在单珠捕获实验中分子马达所经历的垂直（z）力，加速了分子马达从微管上的脱离。在此，我们通过在分子马达和被捕获的珠子之间使用长DNA柄，大幅降低了z力，并对单个和多个驱动蛋白-1的运动性和力产生进行了表征。与之前的观点相反，我们表明驱动蛋白-1是一种强大的分子马达，在达到高阻碍负载之前能抵抗微管脱离，但即使在低z力下，在辅助负载下也会迅速脱离。我们还展示了多个驱动蛋白-1分子马达能高效地产生集体力。这些结果解释了多个驱动蛋白如何协同执行需要比单个分子马达所能承受的更高力的细胞功能。
