Filament Rigidity Vies with Mesh Size in Determining Anomalous Diffusion in Cytoskeleton
Filament Rigidity Vies with Mesh Size in Determining Anomalous Diffusion in Cytoskeleton
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DOI：
10.1021/acs.biomac.9b01057
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发表时间：
2019-12-01
影响因子：
6.2
通讯作者：
McGorty, Ryan
中科院分区：
文献类型：
--
作者：
Anderson, Sylas J.;Matsuda, Christelle;McGorty, Ryan
微观颗粒在细胞中的扩散对于病毒感染、基因传递和囊泡运输等过程很重要，这在很大程度上受复杂的细胞骨架网络控制，该网络由半柔性肌动蛋白丝和刚性微管组成，遍布细胞质。通过改变肌动蛋白和微管的相对浓度，细胞骨架可以显示出许多不同的结构和动力学特性，这些特性反过来影响颗粒通过复合网络的扩散。在这里，我们耦合单粒子跟踪差分动态显微镜的特点微球示踪剂扩散通过复合材料在体外网络与不同比例的肌动蛋白和微管的运输。我们分析了异常传输的多个互补度量，表明粒子在所有网络中都表现出异常的次扩散，我们的数据表明这是由网络的笼化引起的。此外，富肌动蛋白网络的亚扩散特征明显更加明显，与富微管复合材料相比，富肌动蛋白网络表现出同样更突出的粘弹特性。虽然与富含微管的复合材料相比，富含肌动蛋白的复合材料的较小的网孔尺寸在这些结果中起着重要作用，但构成网络的细丝的刚性也影响我们观察到的异常特征。我们的研究结果表明，在我们的复合材料中的微管被肌动蛋白丝取代，降低丝刚性与增加网络连接驱动异常运输的竞争。
The diffusion of microscopic particles through the cell, important to processes such as viral infection, gene delivery, and vesicle transport, is largely controlled by the complex cytoskeletal network, comprised of semiflexible actin filaments and rigid microtubules, that pervades the cytoplasm. By varying the relative concentrations of actin and micro tubules, the cytoskeleton can display a host of different structural and dynamic properties that, in turn, impact the diffusion of particles through the composite network. Here, we couple single-particle tracking with differential dynamic microscopy to characterize the transport of microsphere tracers diffusing through composite in vitro networks with varying ratios of actin and microtubules. We analyze multiple complementary metrics for anomalous transport to show that particles exhibit anomalous subdiffusion in all networks, which our data suggest arises from caging by networks. Further, subdiffusive characteristics are markedly more pronounced in actin rich networks, which exhibit similarly more prominent viscoelastic properties compared to microtubule-rich composites. While the smaller mesh size of actin-rich composites compared to microtubule-rich composites plays an important role in these results, the rigidity of the filaments comprising the network also influences the anomalous characteristics that we observe. Our results suggest that as microtubules in our composites are replaced with actin filaments, the decreasing filament rigidity competes with increasing network connectivity to drive anomalous transport.