Grieb Mason, Krishnan Nimisha, Ross Jennifer L
Syracuse University, Physics department, Syracuse, New York 13244, USA.
Phys Rev E. 2025 Feb;111(2-1):024413. doi: 10.1103/PhysRevE.111.024413.
The kinesin superfamily of motor proteins is a major driver of anterograde transport of vesicles and organelles within eukaryotic cells via microtubules. Numerous studies have elucidated the step size, velocities, forces, and navigation ability of kinesins both in reconstituted systems and in live cells. Outside of cells, the kinesin-based transport is physically regulated and can be controlled by obstacles or defects in the path or the interaction between several motors on the same cargo. To explore the physical control parameters on kinesin-driven transport, we created increasingly dense microtubule networks in vitro to test how kinesin cargoes made from quantum dots with one to 10 kinesin motors attached are able to navigate the network. We find that many motors on the quantum dot increase the distance walked by a factor of 2, association time increased by a factor of 4 to 5, and the average speed by a factor of 2. We quantified the tortuosity and the trajectory persistence length and found the persistence length increased by a factor of 5 to 8 when multiple motors are on the cargo. We also find that these transport parameters depend linearly on the mesh size of the dense network for cargoes with multiple motors. Thus, both motor number and network density are physical aspects that regulate where cargoes traverse in space and time.
驱动蛋白超家族的运动蛋白是真核细胞内囊泡和细胞器通过微管进行顺行运输的主要驱动力。众多研究已经阐明了驱动蛋白在重组系统和活细胞中的步长、速度、力和导航能力。在细胞外，基于驱动蛋白的运输受到物理调节，并且可以由路径中的障碍物或缺陷或同一货物上多个马达之间的相互作用来控制。为了探索驱动蛋白驱动运输的物理控制参数，我们在体外创建了密度越来越高的微管网络，以测试由附着有一到十个驱动蛋白马达的量子点制成的驱动蛋白货物如何在网络中导航。我们发现量子点上的许多马达使行走距离增加了2倍，结合时间增加了4到5倍，平均速度增加了2倍。我们对曲折度和轨迹持续长度进行了量化，发现当货物上有多个马达时，持续长度增加了5到8倍。我们还发现，对于带有多个马达的货物，这些运输参数与密集网络的网格大小呈线性关系。因此，马达数量和网络密度都是调节货物在空间和时间上移动位置的物理因素。
