Hsc70-induced changes in clathrin-auxilin cage structure suggest a role for clathrin light chains in cage disassembly.
Hsc70-induced changes in clathrin-auxilin cage structure suggest a role for clathrin light chains in cage disassembly.
复制标题
Hsc70 诱导的网格蛋白-辅助蛋白笼结构的变化表明网格蛋白轻链在笼拆卸中的作用。
DOI：
10.1111/tra.12085
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
Young A
中科院分区：
文献类型：
--
作者：
Young A
分子伴侣 Hsc70 与其辅助因子 auxilin 一起，在网格蛋白介导的细胞内吞作用过程中促进 ATP 依赖性网格蛋白的去除。我们使用冷冻电子显微镜确定了网格蛋白、辅助素401-910和Hsc70在pH 6、ATP存在下的复合物的3D结构，添加Hsc70后20秒内冷冻，以便在网格蛋白分解之前可视化Hsc70与网格蛋白和辅助素结合后的事件。在这张图中，我们观察到笼子顶点下方的密度，我们将其归因于结合的 Hsc70。这种密度从网格蛋白顶点不对称地出现，表明 Hsc70 优先结合顶点的三个可能位点之一。与我们之前发表的整个辅助素和网格蛋白图谱的统计比较揭示了统计显着差异的位置，这表明网格蛋白轻链参与了 Hsc70 招募后发生的结构重排。使用光散射的网格蛋白分解测定表明，网格蛋白轻链的损失降低了辅助素促进该反应的效率。这些数据支持网格蛋白轻链除了在调节网格蛋白组装中的既定作用之外，还在网格蛋白分解中发挥调节作用。
The molecular chaperone, Hsc70, together with its co‐factor, auxilin, facilitates the ATP‐dependent removal of clathrin during clathrin‐mediated endocytosis in cells. We have used cryo‐electron microscopy to determine the 3D structure of a complex of clathrin, auxilin401‐910and Hsc70 at pH 6 in the presence of ATP, frozen within 20 seconds of adding Hsc70 in order to visualize events that follow the binding of Hsc70 to clathrin and auxilin before clathrin disassembly. In this map, we observe density beneath the vertex of the cage that we attribute to bound Hsc70. This density emerges asymmetrically from the clathrin vertex, suggesting preferential binding by Hsc70 for one of the three possible sites at the vertex. Statistical comparison with a map of whole auxilin and clathrin previously published by us reveals the location of statistically significant differences which implicate involvement of clathrin light chains in structural rearrangements which occur after Hsc70 is recruited. Clathrin disassembly assays using light scattering suggest that loss of clathrin light chains reduces the efficiency with which auxilin facilitates this reaction. These data support a regulatory role for clathrin light chains in clathrin disassembly in addition to their established role in regulating clathrin assembly.