Nasirimarekani Vahid, Subramani Smrithika, Herzog Sebastian, Vilfan Andrej, Guido Isabella
Max Planck Institute for Dynamics and Self-Organization (MPIDS), Am Fassberg 17, 37077Göttingen, Germany.
Department of Physics, University of Wisconsin-Milwaukee, 3135 N Maryland Avenue, Milwaukee, Wisconsin53211, United States.
ACS Omega. 2022 Nov 18;7(48):43820-43828. doi: 10.1021/acsomega.2c04958. eCollection 2022 Dec 6.
Active networks of biopolymers and motor proteins in vitro self-organize and exhibit dynamic structures on length scales much larger than the interacting individual components of which they consist. How the dynamics is related across the range of length scales is still an open question. Here, we experimentally characterize and quantify the dynamic behavior of isolated microtubule bundles that bend due to the activity of motor proteins. At the motor level, we track and describe the motion features of kinesin-1 clusters stepping within the bending bundles. We find that there is a separation of length scales by at least 1 order of magnitude. At a run length of <1 μm, kinesin-1 activity leads to a bundle curvature in the range of tens of micrometers. We propose that the distribution of microtubule polarity plays a crucial role in the bending dynamics that we observe at both the bundle and motor levels. Our results contribute to the understanding of fundamental principles of vital intracellular processes by disentangling the multiscale dynamics in out-of-equilibrium active networks composed of cytoskeletal elements.
体外生物聚合物和运动蛋白的活性网络能够自我组织，并在比其组成的相互作用单个组件大得多的长度尺度上展现出动态结构。跨长度尺度范围的动力学如何关联仍是一个悬而未决的问题。在此，我们通过实验表征并量化了因运动蛋白活性而弯曲的孤立微管束的动态行为。在运动蛋白层面，我们追踪并描述了在弯曲微管束中行走的驱动蛋白-1簇的运动特征。我们发现长度尺度至少有一个数量级的分离。在运行长度小于1微米时，驱动蛋白-1的活性会导致几十微米范围内的微管束曲率。我们提出，微管极性的分布在我们在微管束和运动蛋白层面观察到的弯曲动力学中起着关键作用。我们的结果通过解开由细胞骨架元件组成的非平衡活性网络中的多尺度动力学，有助于理解重要细胞内过程的基本原理。
