钙库操纵性钙内流（Store-operated calcium entry，SOCE）是细胞中钙信号的重要来源，调控一系列重要的细胞功能，与多种生命活动密切相关。介导SOCE的两个重要蛋白STIM1和Orai1的人源的结构及二者的复合物结构一直未得到解析。因此，本报告以探讨CRAC通道相关分子的工作机制与结构解析为核心，为CRAC通道相关疾病的解释与治疗提供理论依据。

       应用活细胞激光共聚焦显微成像和细胞内钙离子检测等技术，以预测的dOrai开放结构为依据，对Orai1的第一至第三跨膜区上的关键位点通过反转电荷的方法进行检测，证明了Orai1在激活时存在“扭转”开放的特性，而Orai1中氨基酸组成的盐桥是这个“扭转”机制存在的关键。因此，Orai1在接收STIM1的激活信号之后会发生一系列的结构重排，其内部跨膜区间的相互作用使其成为了一个具有钙离子高度选择性的通道。

       Orai1分子结构的解析能够为Orai1的深入研究提供更完整的科学证据。通过解析人源Orai1静息与开放结构，虽然暂未得到高分辨的结构结果，但依据现有的结果发现Orai1激活后各个跨膜螺旋都呈现出结构重排的现象。本研究中也对STIM1、STIM1和Orai1复合物开展了结构解析工作，取得了一些阶段性成果。希望在今后的工作中能够解决在结构解析中遇到的问题，可以继续将这项工作完成。这些工作的完成将对STIM1、Orai1的研究带来巨大的推动作用，为揭示STIM1、Orai1作用机制和探索SOCE与疾病的关系提供新的科学证据，同时也将为离子通道改造应用于疾病治疗提供理论依据。

Store-operated calcium entry (SOCE) is an important source of calcium signal in cells. It regulates a range of cellular functions and is closely related to a variety of life activities. The human structure and complex structure of STIM1 and Orai1, two important proteins that mediate SOCE, have not been analyzed. Therefore, we focus on exploring the working mechanism and structural analysis of CRAC-related molecules, aiming to provide theoretical basis for the interpretation and treatment of CRAC-related diseases.

Based on the predicted open dOrai structure, we characterized the key sites in TM1 and TM3 of Orai1 by confocal imaging and intracellular calcium imaging assays, and demonstrated the "twist to open” mechanism of dOrai. The salt bridges formed between TM1 and TM3 are key to this twisting mechanism. Therefore, dOrai undergoes a series of structural rearrangements after STIM1 activation, and its internal interactions make it a highly selective channel for calcium ions.

The molecular structure of Orai1 can provide more scientific evidence for further study of Orai1. By analyzing the resting and open structures of human Orai1, though high-resolution structure has not been obtained yet, the existing results still show structure rearrangement of each transmembrane helix caused by Orai1 activation. In addition, we also pay effort to make out the structure of STIM1 and STIM1-Orai1 complexes, and some preliminary achievements were obtained. We hope that the problems encountered in structure analysis can be solved in the future work, and this study could continue to be completed. These works will greatly promote the research on STIM1 and Orai1, and provide new scientific evidence for revealing the mechanism of CRAC channels and exploring the relationship between SOCE and diseases. Meanwhile, these will also accelerate therapies targeting CRAC channels. At the same time, it will provide a theoretical basis for the application of ion channel modification in disease treatment.