Thickness distribution of actin bundles in vitro
Thickness distribution of actin bundles in vitro
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DOI：
10.1007/s00249-007-0236-1
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发表时间：
2008-04-01
影响因子：
2
通讯作者：
Bernheim-Groswasser, Anne
中科院分区：
文献类型：
--
作者：
Haviv, Lior;Gov, Nir;Bernheim-Groswasser, Anne
成束的丝状肌动蛋白形成广泛的细胞骨架结构的主要构件，包括丝状伪足、静纤毛和微绒毛。在每种情况下，细胞使用特定的相关蛋白质来调整束的动力学，尺寸和机械特性，以适应特定的细胞功能。虽然肌动蛋白束的长度分布已被广泛研究，但对厚度分布几乎一无所知。在这里，我们使用高分辨率的低温透射电镜测量肌动蛋白/肌成束的厚度分布，在体外。我们发现，厚度分布有一个突出的峰值，与指数尾，支持的情况下，最初快速形成的短肌动蛋白丝的盘状核，这只是后来拉长。在稳定状态下的束厚度被发现遵循的初始核的分布，表明没有横向合并发生。我们的研究结果表明，束的厚度分布可以通过监测初始成核过程来控制。在体内，这是通过使用特定的调节蛋白复合物来完成的。
Bundles of filamentous actin form the primary building blocks of a broad range of cytoskeletal structures, including filopodia, stereocilia and microvilli. In each case, the cell uses specific associated proteins to tailor the dynamics, dimensions and mechanical properties of the bundles to suit a specific cellular function. While the length distribution of actin bundles was extensively studied, almost nothing is known about the thickness distribution. Here, we use high-resolution cryo-TEM to measure the thickness distribution of actin/fascin bundles, in vitro. We find that the thickness distribution has a prominent peak, with an exponential tail, supporting a scenario of an initial fast formation of a disc-like nucleus of short actin filaments, which only later elongates. The bundle thicknesses at steady state are found to follow the distribution of the initial nuclei indicating that no lateral coalescence occurs. Our results show that the distribution of bundles thicknesses can be controlled by monitoring the initial nucleation process. In vivo, this is done by using specific regulatory proteins complexes.