Transition to superdiffusive behavior in intracellular actin-based transport mediated by molecular motors
Transition to superdiffusive behavior in intracellular actin-based transport mediated by molecular motors
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DOI：
10.1103/physreve.80.011912
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发表时间：
2009-07-01
影响因子：
2.4
通讯作者：
Desposito, M. A.
中科院分区：
文献类型：
--
作者：
Bruno, L.;Levi, V.;Desposito, M. A.
细胞内运输的大型货物，如细胞器，囊泡，或大蛋白质，是一个复杂的动力学过程，涉及相互作用的腺苷三磷酸消耗分子马达，细胞骨架丝，和粘弹性的细胞质。在这项工作中，我们研究了运动的色素细胞器（黑素体）驱动肌球蛋白V马达在非洲爪蟾黑素细胞使用高时空分辨率跟踪技术。通过分析得到的轨迹，我们表明，黑素体均方位移经历了一个过渡从subdiffusive到superdiffusive行为。一个随机的理论模型，它明确地考虑了分子马达的集体行动，被引入到概括我们的数据的解释。从广义朗之万方程出发，导出了均方位移的解析表达式，该表达式也考虑了实验噪声。通过拟合理论表达式的实验数据，我们能够区分的指数，表征被动和主动的动态贡献，并正确估计的“全球”电机的力量。然后，我们的模型给出了一个定量的描述，在活细胞中的主动运输的参数减少。
Intracellular transport of large cargoes, such as organelles, vesicles, or large proteins, is a complex dynamical process that involves the interplay of adenosine triphosphate-consuming molecular motors, cytoskeleton filaments, and the viscoelastic cytoplasm. In this work we investigate the motion of pigment organelles (melanosomes) driven by myosin-V motors in Xenopus laevis melanocytes using a high-spatio-temporal resolution tracking technique. By analyzing the obtained trajectories, we show that the melanosomes mean-square displacement undergoes a transition from a subdiffusive to a superdiffusive behavior. A stochastic theoretical model, which explicitly considers the collective action of the molecular motors, is introduced to generalize the interpretation of our data. Starting from a generalized Langevin equation, we derive an analytical expression for the mean square displacement, which also takes into account the experimental noise. By fitting theoretical expressions to experimental data we were able to discriminate the exponents that characterize the passive and active contributions to the dynamics and to estimate the "global" motor forces correctly. Then, our model gives a quantitative description of active transport in living cells with a reduced number of parameters.