Fluctuation Analysis of Centrosomes Reveals a Cortical Function of Kinesin-1.
Fluctuation Analysis of Centrosomes Reveals a Cortical Function of Kinesin-1.
复制标题
DOI：
10.1016/j.bpj.2015.07.044
复制
发表时间：
2015-09-01
影响因子：
3.4
通讯作者：
Grosshans J
中科院分区：
文献类型：
--
作者：
Winkler F;Gummalla M;Künneke L;Lv Z;Zippelius A;Aspelmeier T;Grosshans J
肌动蛋白和微管网络形成动态的细胞骨架。网络动力学是由分子马达驱动的，分子马达向网络施加力以及网络之间的相互作用。在这里，我们分析中心体的动态在秒的规模作为一个代理微管星状体的运动。通过这种检测，我们希望检测特定马达和网络相互作用的作用。在果蝇合胞胚分裂间期，皮层肌动蛋白和微管网络相互依赖。中心体诱导皮质肌动蛋白形成帽，而F-肌动蛋白锚微管皮质。此外，微管星状体之间的横向相互作用被认为是重要的合胞体胚胎的定期空间组织。到目前为止，微管星形细胞和皮质肌动蛋白之间的功能相互作用主要是以静态的方式分析的。我们记录了中心体在1赫兹的运动，并分析了两个过程的波动-对分离和个人的运动。我们发现，F-肌动蛋白是所需的定向运动在初始中心体对分离，因为分离进行扩散的方式在latrunculin注射胚胎。为了测定个体的运动，我们建立了一个波动参数作为时间和空间缓慢变化的漂移运动的偏差。通过对突变体和药物注射胚胎的分析，我们发现这种波动受到皮层肌动蛋白和微管的抑制。令人惊讶的是，微管马达Kinesin-1也抑制波动到与F-肌动蛋白相似的程度。驱动蛋白-1可能介导微管（+）-末端与肌动蛋白皮质的连接。与该模型一致的是，我们发现驱动蛋白-1-GFP在皮质肌动蛋白帽处积累。
The actin and microtubule networks form the dynamic cytoskeleton. Network dynamics is driven by molecular motors applying force onto the networks and the interactions between the networks. Here we assay the dynamics of centrosomes in the scale of seconds as a proxy for the movement of microtubule asters. With this assay we want to detect the role of specific motors and of network interaction. During interphase of syncytial embryos of Drosophila, cortical actin and the microtubule network depend on each other. Centrosomes induce cortical actin to form caps, whereas F-actin anchors microtubules to the cortex. In addition, lateral interactions between microtubule asters are assumed to be important for regular spatial organization of the syncytial embryo. The functional interaction between the microtubule asters and cortical actin has been largely analyzed in a static manner, so far. We recorded the movement of centrosomes at 1 Hz and analyzed their fluctuations for two processes—pair separation and individual movement. We found that F-actin is required for directional movements during initial centrosome pair separation, because separation proceeds in a diffusive manner in latrunculin-injected embryos. For assaying individual movement, we established a fluctuation parameter as the deviation from temporally and spatially slowly varying drift movements. By analysis of mutant and drug-injected embryos, we found that the fluctuations were suppressed by both cortical actin and microtubules. Surprisingly, the microtubule motor Kinesin-1 also suppressed fluctuations to a similar degree as F-actin. Kinesin-1 may mediate linkage of the microtubule (+)-ends to the actin cortex. Consistent with this model is our finding that Kinesin-1-GFP accumulates at the cortical actin caps.