内质网上的蛋白质RCN2与STIM1-Orai1复合体相互作用(英文)

An ER Locating Protein Named RCN2 Interacts With STIM1-Orai1 Complex

膜蛋白质Orai1组成了一类被称为钙释放激活钙通道(CRAC)的离子通道,并且由相互作用的蛋白质STIM1作为其在内质网上的钙感受器.但是这类通道的调节机制还未研究透彻.通过串连亲和纯化STIM1-Orai1复合体,发现与之相互作用的内质网蛋白质RCN2.共聚焦显微术显示RCN2与STIM1在钙库排空前后完全共定位.对RCN2的EF hands结构突变体所作单细胞测钙,结果显示其对钙库操控通道电流特性有微弱影响.全内反射荧光显微术显示,RCN2以花环状围绕包围STIM1聚集堆,这提示RCN2在STIM1聚集中起到一种结构约束作用.

STIM1 is recognized as an ER Ca^2＋ sensor of calcium release-activated calcium （CRAC） channel that is constructed by membrane protein Orail, However, this regulatory system may also be regulated by other proteins. Reticulocalbin 2 （RCN2） was purified and identified from STIM1-Orai1 complex. Confocal microscopy revealed that RCN2 co-localized with STIM1 in ER before and after Ca^2＋ store depletion. Single cell [Ca^2＋]i measurements of RCN2 EF hands mutant showed slight influence on SOC electrophysiological characters. Furthermore, a novel collar form aggregation of RCN2 surrounding STIM1 clusters suggested that RCN2 potentially plays a role of structure maintenance in STIM1 clustering.