Two populations of cytoplasmic dynein contribute to spindle positioning in C. elegans embryos
Two populations of cytoplasmic dynein contribute to spindle positioning in C. elegans embryos
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DOI：
10.1083/jcb.201607038
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发表时间：
2017-09-01
影响因子：
7.8
通讯作者：
van den Heuvel, Sander
中科院分区：
文献类型：
--
作者：
Schmidt, Ruben;Fielmich, Lars-Eric;van den Heuvel, Sander
有丝分裂纺锤体的位置在动物细胞中受到严格控制，因为它决定了细胞分裂的平面和方向。细胞质动力蛋白和细胞皮层的星形微管（MT）之间的接触产生定位纺锤体的拉力。进化上保守的G α-GPR-1/2（Pins/LGN）-LIN-5（Mud/NuMA）皮质复合物与动力蛋白相互作用，并且是产生拉力所必需的，但该过程的动力学仍不清楚。在这项研究中，通过荧光标记内源性蛋白质在秀丽隐杆线虫胚胎，我们表明，动力蛋白存在于两个不同的皮质人口。一个群体直接依赖于LIN-5，而另一个集中在MT+末端，并依赖于末端结合（EB）蛋白。敲除突变体缺乏所有EB是可行的和肥沃的，并显示正常的拉力和纺锤体定位。然而，EB蛋白依赖性动力蛋白加上末端跟踪被发现有助于力的产生在胚胎与部分扰动的动力蛋白功能，表明存在两种机制，共同创建一个高度强大的力产生系统。
The position of the mitotic spindle is tightly controlled in animal cells as it determines the plane and orientation of cell division. Contacts between cytoplasmic dynein and astral microtubules (MTs) at the cell cortex generate pulling forces that position the spindle. An evolutionarily conserved G alpha-GPR-1/2(Pins/LGN)-LIN-5(Mud/NuMA) cortical complex interacts with dynein and is required for pulling force generation, but the dynamics of this process remain unclear. In this study, by fluorescently labeling endogenous proteins in Caenorhabditis elegans embryos, we show that dynein exists in two distinct cortical populations. One population directly depends on LIN-5, whereas the other is concentrated at MT plus ends and depends on end-binding (EB) proteins. Knockout mutants lacking all EBs are viable and fertile and display normal pulling forces and spindle positioning. However, EB protein-dependent dynein plus end tracking was found to contribute to force generation in embryos with a partially perturbed dynein function, indicating the existence of two mechanisms that together create a highly robust force-generating system.