Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Química Biológica, Laboratorio de Dinámica Intracelular, Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), Buenos Aires, Argentina.
Fundación Instituto Leloir, CONICET, Buenos Aires, Argentina.
Biochim Biophys Acta Gen Subj. 2017 Dec;1861(12):3178-3189. doi: 10.1016/j.bbagen.2017.09.009. Epub 2017 Sep 19.
Intracellular transport requires molecular motors that step along cytoskeletal filaments actively dragging cargoes through the crowded cytoplasm. Here, we explore the interplay of the opposed polarity motors kinesin-1 and cytoplasmic dynein during peroxisome transport along microtubules in Drosophila S2 cells.
We used single particle tracking with nanometer accuracy and millisecond time resolution to extract quantitative information on the bidirectional motion of organelles. The transport performance was studied in cells expressing a slow chimeric plus-end directed motor or the kinesin heavy chain. We also analyzed the influence of peroxisomes membrane fluidity in methyl-β-ciclodextrin treated cells. The experimental data was also confronted with numerical simulations of two well-established tug of war scenarios.
The velocity distributions of retrograde and anterograde peroxisomes showed a multimodal pattern suggesting that multiple motor teams drive transport in either direction. The chimeric motors interfered with the performance of anterograde transport and also reduced the speed of the slowest retrograde team. In addition, increasing the fluidity of peroxisomes membrane decreased the speed of the slowest anterograde and retrograde teams.
Our results support the existence of a crosstalk between opposed-polarity motor teams. Moreover, the slowest teams seem to mechanically communicate with each other through the membrane to trigger transport.
细胞内运输需要分子马达沿着细胞骨架丝主动地移动货物，穿过拥挤的细胞质。在这里，我们探索了在果蝇 S2 细胞中沿着微管进行过氧化物酶体运输时，相反极性的驱动蛋白-1（kinesin-1）和细胞质动力蛋白之间的相互作用。
我们使用单颗粒跟踪技术，具有纳米级精度和毫秒级时间分辨率，提取细胞器双向运动的定量信息。在表达慢的杂种正向末端导向马达或驱动蛋白重链的细胞中研究了运输性能。我们还分析了在甲基-β-环糊精处理的细胞中过氧化物酶体膜流动性的影响。实验数据还与两种成熟的拔河场景的数值模拟进行了对比。
逆行和顺行过氧化物酶体的速度分布呈多模态模式，表明多个马达团队在任何方向上都驱动运输。杂种马达干扰了顺行运输的性能，也降低了最慢逆行团队的速度。此外，增加过氧化物酶体膜的流动性会降低最慢的顺行和逆行团队的速度。
我们的结果支持相反极性的马达团队之间存在串扰。此外，最慢的团队似乎通过膜与其他团队进行机械通信，以触发运输。
