GPI锚去脂酰基酶Bst1p突变促进COPII囊泡转运甘油二酯的机制研究

甘油二酯（DAG）在细胞内堆积可导致内质网、高尔基体等细胞器的脂膜稳态失衡。脂质转运是解决脂质堆积造成膜系统破坏的方法之一，然而关于DAG在细胞内的转运调控机制目前还没有研究。申请人在前期的研究中发现DAG在内质网聚集形成颗粒结构可引发细胞器损伤和自噬缺陷，而初步的基因组筛选发现，Bst1p敲除可以抑制DAG颗粒形成且不降低DAG总量。因此提出以下假说：细胞存在负责转运DAG的机制，Bst1p突变的作用可能是抑制GPI-APs进入COPII囊泡，导致货物分选过程的严谨性降低，进而促进内质网成分DAG被COPII囊泡装载转运。为了验证以上假说，拟通过以下方案开展研究：（1）验证COPII囊泡在DAG转运过程中的必要性；（2）探索货物分选过程的严谨性与DAG转运的关系；（3）阐明GPI锚蛋白与货物分选严谨性以及DAG转运之间的关系；（4）寻找并研究其他可能参与DAG转运的蛋白。

The accumulation of diacylglycerol (DAG) could induce the dysfunction of membrane system of endoplasmic reticulum (ER), Golgi and other cell organelles. Lipid transport is one method to solve this damage caused by lipid over accumulation. However, the mechanism of DAG transport hasn’t been reported now. In previous studies, we found that over accumulated DAG could be assembled into particles on the ER which could induce the dysfunction of cell organelles and autophagy. While, Bst1p knock-out was found to be able to inhibit the formation of DAG particles in our early genome screening work. Therefore, the following hypothesis was put forward: there are mechanisms being responsible for DAGs transport in the cell, and the role of Bst1p mutation may be to inhibit GPI-APs from entering COPII vesicles, which could attenuate ER retention stringency and lead to the transport of DAG by COPII vesicles. To verify the above hypothesis, the following work is proposed to carry out: (1) to verify the necessity of COPII vesicles in DAG transportation; (2) to test the relationships between ER retention stringency and DAG transport; (3) to evaluate the relationship of GPI anchor building, GPI anchor protein sorting, ER retention stringency and DAG transport; (4) to complete the remaining genome-wide screening work and find other mechanisms that may involve in DAG transport.