蛋白质的分选和运输调控机制是生物学的热点研究领域之一。COPII复合体介导蛋白质从内质网向高尔基体的运输，其组分Sar1不仅负责启动运输小泡的组装，还参与货物蛋白分选等其他调控过程，在蛋白转运过程中发挥至关重要作用。植物中Sar1由多基因编码，各亚型的具体功能及调控机制尚不清楚。本项目重点研究三个水稻Sar1亚型的功能及其特异性，利用细胞生物学、遗传学等手段，从水稻生物体内和细胞水平分析各亚型的表达和功能特异性。同时提取内质网蛋白，借助iTRAQ技术，研究各亚型在介导内质网蛋白转运方面的异同。通过体内pull-down和酵母双杂交筛选OsSar1相互作用蛋白，以期找到植物中调控Sar1的新因子。本研究结果有利于深入阐明植物Sar1各亚型参与的蛋白转运复杂调控机制，完善植物COPII组分的功能及其复杂性、特异性，为植物中COPII介导的蛋白转运研究提供新的视角，具有重要理论意义。

Protein sorting and transport regulatory mechanism has made significant advances and become hotspot research now. COPII complex mediated protein transport from the endoplasmic reticulum to the Golgi apparatus. As a component of COPII, Sar1 plays a crucial role in initiating the COPII assembly on the ER, also involves in other regulatory processes such as cargo selection. Sar1 are encoded by multiple genes in plant, and function and regulation mechanism of each isoform is unclear. This study will focus on the function and specificity of 3 OsSar1 isoforms by cell biology and genetics methods. We will analyze the cellular expression and specific function of each isoform in vivo. The similarities and differences of each isoform function on the protein ER export will analyze by iTRAQ technology. The pull-down and yeast two-hybrid will be used to screen the OsSar1 interaction protein. This study will improve the plant COPII components function and its complexity, and elucidate the COPII regulation mechanism in protein transport.