Visualization of cargo concentration by COPII minimal machinery in a planar lipid membrane
Visualization of cargo concentration by COPII minimal machinery in a planar lipid membrane
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DOI：
10.1038/emboj.2009.269
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发表时间：
2009-11-04
期刊：
影响因子：
11.4
通讯作者：
Noji, Hiroyuki
中科院分区：
文献类型：
--
作者：
Tabata, Kazuhito V.;Sato, Ken;Noji, Hiroyuki
内质网的选择性蛋白质输出是由COPII囊泡介导的。在这里，我们研究了荧光标记的货物和非货物蛋白在COPII囊泡形成过程中的动力学，使用单分子显微镜结合人工平面脂质双层。单分子分析表明，在Sec13/31P募集之前，Sar1p-Sec23/24P-Cargo复合体发生了部分二聚，而不是Sar1p-Sec23/24P复合体。在加入完整的COPII混合物后，货物分子开始聚集成荧光点和荧光团，随后囊泡从平面膜中释放出来。我们发现，Sar1p的连续GTPase循环促进了货物向COPII囊泡芽的聚集，同时，非货物蛋白被排除在货物簇之外。我们认为，COPII组分的最小集合不仅需要浓缩货物分子，而且还需要中介将非货物蛋白从COPII囊泡中排除。EMBO期刊(2009)28,3279-3289。DOI：10.1038/Exempj.2009.269；2009年9月17日在线发布
Selective protein export from the endoplasmic reticulum is mediated by COPII vesicles. Here, we investigated the dynamics of fluorescently labelled cargo and non-cargo proteins during COPII vesicle formation using single-molecule microscopy combined with an artificial planar lipid bilayer. Single-molecule analysis showed that the Sar1p-Sec23/24p-cargo complex, but not the Sar1p-Sec23/24p complex, undergoes partial dimerization before Sec13/31p recruitment. On addition of a complete COPII mixture, cargo molecules start to assemble into fluorescent spots and clusters followed by vesicle release from the planar membrane. We show that continuous GTPase cycles of Sar1p facilitate cargo concentration into COPII vesicle buds, and at the same time, non-cargo proteins are excluded from cargo clusters. We propose that the minimal set of COPII components is required not only to concentrate cargo molecules, but also to mediate exclusion of non-cargo proteins from the COPII vesicles. The EMBO Journal (2009) 28, 3279-3289. doi: 10.1038/emboj.2009.269; Published online 17 September 2009