Microscopy analysis of reconstituted COPII coat polymerization and Sec16 dynamics
Microscopy analysis of reconstituted COPII coat polymerization and Sec16 dynamics
复制标题
DOI：
10.1242/jcs.203844
复制
发表时间：
2017-09-01
影响因子：
4
通讯作者：
Sato, Ken
中科院分区：
文献类型：
--
作者：
Iwasaki, Hirohiko;Yorimitsu, Tomohiro;Sato, Ken
COPII外壳和小的GTdR Sar 1通过称为内质网出口位点的专门结构域介导蛋白质从内质网（ER）出口。已提出外周ER蛋白Sec 16组织ER出口位点。然而，目前尚不清楚这些分子如何驱动COPII涂层聚合。在这里，我们的特点是时空的酿酒酵母COPII组件之间的关系，在其聚合过程中进行荧光显微镜的人工平面膜。我们证明，Sar 1解离后不久，COPII涂层招聘的膜，然后Sar 1不再需要COPII涂层结合到膜。此外，我们发现Sec 16被并入COPII-货物簇中，并且这依赖于Sar 1 GTdR循环。这些数据显示了Sar 1如何驱动COPII涂层的聚合以及Sec 16在COPII涂层聚合期间如何空间分布。
The COPII coat and the small GTPase Sar1 mediate protein export from the endoplasmic reticulum (ER) via specialized domains known as the ER exit sites. The peripheral ER protein Sec16 has been proposed to organize ER exit sites. However, it remains unclear how these molecules drive COPII coat polymerization. Here, we characterized the spatiotemporal relationships between the Saccharomyces cerevisiae COPII components during their polymerization by performing fluorescence microscopy of an artificial planar membrane. We demonstrated that Sar1 dissociates from the membrane shortly after the COPII coat recruitment, and Sar1 is then no longer required for the COPII coat to bind to the membrane. Furthermore, we found that Sec16 is incorporated within the COPII-cargo clusters, and that this is dependent on the Sar1 GTPase cycle. These data show how Sar1 drives the polymerization of COPII coat and how Sec16 is spatially distributed during COPII coat polymerization.