Electron tomography reveals Rab6 is essential to the trafficking of trans-Golgi clathrin and COPI-coated vesicles and the maintenance of Golgi cisternal number.
Electron tomography reveals Rab6 is essential to the trafficking of trans-Golgi clathrin and COPI-coated vesicles and the maintenance of Golgi cisternal number.
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DOI：
10.1111/j.1600-0854.2012.01343.x
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发表时间：
2012-05
期刊：
影响因子：
--
通讯作者：
Marsh BJ
中科院分区：
文献类型：
--
作者：
Storrie B;Micaroni M;Morgan GP;Jones N;Kamykowski JA;Wilkins N;Pan TH;Marsh BJ
我们以前已经证明，Rab6是一个小的，跨高尔基体定位的GTP酶，作用于COG和ZW10/RINT1逆行系链复合体的上游，以维持高尔基体的稳态。在这里，我们提出了来自电子显微镜和电子断层扫描的无偏和高分辨率方法的证据，即Rab6对于两种形态的涂层小泡的跨高尔基体运输是必不可少的；较大的对应于笼状蛋白涂层的小泡，较小的对应于COPI涂层的小泡。根据包被囊泡堆积、脑池扩张以及货物从内质网转运到高尔基体的正常动力学以及随后高尔基体到细胞表面转运的延迟，我们认为高尔基体在货物运输中的作用优先于跨高尔基体/TGN的抑制。我们观察到，在Rab6缺失的HeLa细胞中高尔基体池数量增加50%很可能与COPI包被囊泡的反式高尔基体堆积有关；单个Rab6效应器，肌球蛋白IIA的耗尽，产生了未包被囊泡的堆积，如果有什么不同的话，脑池数量减少。这些结果是依赖Rab6的蛋白质机器影响高尔基体近端包被囊泡积累和可能在跨高尔基体运输的第一个证据，也是第一个在抑制运输条件下伴随脑池增殖和高尔基体堆叠组织增加的例子。
We have shown previously that Rab6, a small, trans-Golgi-localized GTPase, acts upstream of the COG and ZW10/RINT1 retrograde tether complexes to maintain Golgi homeostasis. Here, we present evidence from the unbiased and high-resolution approach of electron microscopy and electron tomography that Rab6 is essential to the trans-Golgi trafficking of two morphological classes of coated vesicles; the larger corresponds to clathrin-coated vesicles and the smaller to COPI-coated vesicles. Based on the site of coated vesicle accumulation, cisternal dilation, and the normal kinetics of cargo transport from the ER to Golgi followed by delayed Golgi to cell surface transport, we suggest that Golgi function in cargo transport is preferentially inhibited at the trans-Golgi/TGN. The >50% increase in Golgi cisternae number in Rab6-depleted HeLa cells that we observed may well be coupled to the trans-Golgi accumulation of COPI-coated vesicles; depletion of the individual Rab6 effector, myosin IIA, produced an accumulation of uncoated vesicles with if anything a decrease in cisternal number. These results are the first evidence for a Rab6-dependent protein machine affecting Golgi-proximal, coated vesicle accumulation and likely transport at the trans-Golgi and the first example of concomitant cisternal proliferation and increased Golgi stack organization under inhibited transport conditions.
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