Myosin VI stabilizes an actin network during Drosophila spermatid individualization
Myosin VI stabilizes an actin network during Drosophila spermatid individualization
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DOI：
10.1091/mbc.e06-01-0031
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发表时间：
2006-06-01
影响因子：
3.3
通讯作者：
Miller, KG
中科院分区：
文献类型：
--
作者：
Noguchi, T;Lenartowska, M;Miller, KG
在这里，我们证明了肌球蛋白VI的新功能，通过观察果蝇精子的个体化在体内。我们发现肌凝蛋白VI稳定了肌动蛋白结构（锥体）中的分支肌动蛋白网络，该网络介导合胞精子的分离。在myosin VI突变体中，锥体在锥体运动过程中不积累f -肌动蛋白，而myosin VI的过度表达导致锥体变大，含有更多的f -肌动蛋白。肌凝蛋白亚片段1-片段装饰表明肌动蛋白锥体由两个区域组成：前部密集的网状结构和后部平行的束状结构。肌动蛋白丝大部分呈锥形运动方向，其尖端呈锥形运动方向。我们的数据还表明，肌凝蛋白VI使用其运动结构域与锥体前部结合。使用绿色荧光蛋白-肌凝蛋白VI进行光漂白实验后的荧光恢复显示，肌凝蛋白VI与f -肌动蛋白结合数分钟，表明其作用是拴住，而不是运输货物。我们假设肌凝蛋白VI通过交联肌动蛋白丝或在锥体前部锚定调节分子来保护肌动蛋白锥体结构。这些观察结果揭示了一种由肌球蛋白VI介导的稳定细胞中长寿命肌动蛋白结构的新机制。
Here, we demonstrate a new function of myosin VI using observations of Drosophila spermatid individualization in vivo. We find that myosin VI stabilizes a branched actin network in actin structures (cones) that mediate the separation of the syncytial spermatids. In a myosin VI mutant, the cones do not accumulate F-actin during cone movement, whereas overexpression of myosin VI leads to bigger cones with more F-actin. Myosin subfragment 1-fragment decoration demonstrated that the actin cone is made up of two regions: a dense meshwork at the front and parallel bundles at the rear. The majority of the actin filaments were oriented with their pointed ends facing in the direction of cone movement. Our data also demonstrate that myosin VI binds to the cone front using its motor domain. Fluorescence recovery after photobleach experiments using green fluorescent protein-myosin VI revealed that myosin VI remains bound to F-actin for minutes, suggesting its role is tethering, rather than transporting cargo. We hypothesize that myosin VI protects the actin cone structure either by cross-linking actin filaments or anchoring regulatory molecules at the cone front. These observations uncover a novel mechanism mediated by myosin VI for stabilizing long-lived actin structures in cells.