Wang Jin, Li Lei, Ming Zhenhua, Wu Lijie, Yan Liming
State Key Laboratory of Biotherapy, West China Hospital, Collaborative Innovation Center for Biotherapy, Sichuan University, Chengdu 610041, China.
Laboratory of Structural Biology and MOE Laboratory of Protein Science, School of Medicine, Tsinghua University, Beijing 100084, China.
Int J Mol Sci. 2021 Apr 7;22(8):3812. doi: 10.3390/ijms22083812.
Tubules of the endoplasmic reticulum (ER) spread into the buds of yeast by an actin-based mechanism and, upon entry, become attached to the polarisome, a proteinaceous micro-compartment below the tip of the bud. The minimal tether between polarisome and cortical ER is formed by a protein complex consisting of Epo1, a member of the polarisome, Scs2, a membrane protein of the ER and Cdc42 guanosine triphosphatase-activating protein Bem3. Here, we report the crystal structure of a complex between Epo1 and Bem3. In addition, we characterize through the hydrogen/deuterium (H/D) exchange assay the interface between Scs2 and Epo1. Our findings provide a first structural insight into the molecular architecture of the link between cortical ER and the polarisome.
内质网（ER）的小管通过基于肌动蛋白的机制延伸到酵母芽中，并在进入芽后附着于极化体，极化体是芽尖下方的一种蛋白质微区室。极化体与皮质内质网之间的最小连接物由一个蛋白质复合物形成，该复合物由极化体成员Epo1、内质网的膜蛋白Scs2和Cdc42鸟苷三磷酸酶激活蛋白Bem3组成。在这里，我们报告了Epo1和Bem3之间复合物的晶体结构。此外，我们通过氢/氘（H/D）交换测定法表征了Scs2和Epo1之间的界面。我们的研究结果首次提供了关于皮质内质网与极化体之间联系的分子结构的结构见解。
