OsDer1在内质网相关蛋白降解途径中的功能及其作用机理

内质网相关蛋白降解（ERAD）调控机制是生物学的一个基本问题，已成为当代生物学的热点研究领域之一。ERAD在非正确折叠蛋白降解、缓解内质网胁迫、维持ER平衡过程中发挥重要功能，参与生物体的抗病及抗胁迫等多个重要生物学过程。ERAD是由许多因子参与的复杂调控过程，其中Derlin蛋白在错误折叠蛋白底物识别、泛素化和逆向运输中发挥重要作用。目前对Der1功能研究方面多限于哺乳动物和酵母中，对其在植物中的功能尚少见报道。在前期通过对ER胁迫水稻种子内质网膜蛋白进行蛋白质组学分析发现一个表达量极显著上调的Derlin-like（OsDer1）蛋白，并证明其表达受ER胁迫诱导。同时利用免疫共沉淀技术获得了一些可能与OsDer1相互作用的蛋白。在此基础上，本研究对其功能进行详尽研究，以期逐步揭示水稻ERAD的遗传调控机制，对高等植物的ERAD机理提出新的见解，具有重大的理论意义。

Regulatory mechanism of endoplasmic reticulum associated protein degradation (ERAD) is one of the basic biological questions and has been becoming one of the hot areas of modern biology. ERAD plays critical roles in removing misfolded proteins, regulating important biochemical/physiological processes, including abiotic stress tolerance and plant defense. To date, most of the ERAD studies were concentrated on yeast and mammalian systems. Recent studies revealed that the ERAD machinery is conserved in plants. Derlin 1 is involved in substrate recognition, ubiquitination, and extraction of ERAD substrates. However, less is known about the function of Derlins in plants. Previously, we identified a Derlin-like protein (OsDer1) through proteomic analysis of the ER isolated from ER-stressed developing rice seed. The expression of OsDer1 was dramatically upregulated under ER-stress conditions. We also obtained some candidate proteins that interact with OsDer1 through CoIP experiments. In this study, we will focus on the identification and characterization of OsDer1 via biochemical, molecular and cellular biological strategies. The expected results will help us to reveal the molecular mechanisms of ERAD in rice. We will also evaluate the potentials of OsDer1 in stress-tolerance rice breeding.