Quantitative analysis of microtubule dynamics during adhesion-mediated growth cone guidance
Quantitative analysis of microtubule dynamics during adhesion-mediated growth cone guidance
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DOI：
10.1002/dneu.20662
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发表时间：
2008-10-01
影响因子：
3
通讯作者：
Suter, Daniel M.
中科院分区：
文献类型：
--
作者：
Lee, Aih Cheun;Suter, Daniel M.
在粘附介导的神经元生长锥引导过程中，微管发生重大重排。然而，它是未知的微管是否延伸到粘附位点，因为在加端聚合和/或易位动力学的变化，因为肌动蛋白微管相互作用的变化，或者因为他们遵循肌动蛋白细胞骨架的重组。在这里，我们使用荧光散斑显微镜直接量化微管和肌动蛋白动力学在Aesthesia生长锥，因为他们转向珠涂有细胞粘附分子apCAM。在粘附形成的初始阶段，在周边域的动态微管优先探索apCAM珠之前，生长锥形态和逆行肌动蛋白流的变化。有趣的是，这些早期的微管具有不变的聚合速率，但由于从肌动蛋白流解偶联而在逆行易位中花费的时间较少。然而，探索粘附位点的微管在解聚中花费较少的时间。在牵引力产生的后期，由于肌动蛋白流动的衰减和F-肌动蛋白结构的清除，中央结构域的进展和更多的微管在外周结构域延伸。然而，在过渡区和中央域中的微管分别与肌动蛋白弧和束一起向粘附位点移位。我们的结论是，粘附分子引导神经元生长锥和相关微管重排主要是通过差异调节微管肌动蛋白耦合和肌动蛋白运动根据生长锥区域，而不是通过控制加端聚合速率。(C)2008年，Wiley期刊。Inc.
During adhesion-mediated neuronal growth cone guidance microtubules undergo major rearrangements. However, it is unknown whether microtubules extend to adhesion sites because of changes in plus-end polymerization and/or translocation dynamics, because of changes in actin-microtubule interactions, or because they follow the reorganization of the actin cytoskeleton. Here, we used fluorescent speckle microscopy to directly quantify microtubule and actin dynamics in Aplysia growth cones as they turn towards beads coated with the cell adhesion molecule apCAM. During the initial phase of adhesion formation, dynamic microtubules in the peripheral domain preferentially explore apCAM-beads prior to changes in growth cone morphology and retrograde actin flow. Interestingly, these early microtubules have unchanged polymerization rates but spend less time in retrograde translocation due to uncoupling from actin flow. Forthermore, microtubules exploring the adhesion site spend less time in depolymerization. During the later phase of traction force generation, the central domain advances and more microtubules in the peripheral domain extend because of attenuation of actin flow and clearance of F-actin structures. Microtubules in the transition zone and central domain, however, translocate towards the adhesion site in concert with actin arcs and bundles, respectively. We conclude that adhesion molecules guide neuronal growth cones and underlying microtubule rearrangements largely by differentially regulating microtubule-actin coupling and actin movements according to growth cone region and not by controlling plus-end polymerization rates. (C) 2008 Wiley Periodicals. Inc.