Mapping the interacting domains of STIM1 and Orai1 in Ca2+ release-activated Ca2+ channel activation
Mapping the interacting domains of STIM1 and Orai1 in Ca2+ release-activated Ca2+ channel activation
复制标题
绘制 Ca2 释放激活的 Ca2 通道激活中 STIM1 和 Orai1 的相互作用域
DOI：
10.1074/jbc.m703573200
复制
发表时间：
2007-10-05
影响因子：
4.8
通讯作者：
Xu, Tao
中科院分区：
文献类型：
--
作者：
Li, Zhengzheng;Lu, Jingze;Xu, Tao
STIM 1和Orai 1是钙释放激活的钙通道（CRACs）的重要组成部分。在内质网Ca 2+库耗尽后，内质网中的STIM 1聚集并向细胞外周迁移，与相对质膜上的Orai 1共定位。关于STIM 1和Orai 1的不同结构域在蛋白质聚集、迁移、相互作用以及最终打开CRAC通道中的作用知之甚少。在这里，我们表明，卷曲螺旋结构域在C末端的STIM 1是至关重要的，它的聚集。STIM 1的氨基酸425-671含有富含丝氨酸-脯氨酸的区域，对于在钙库耗尽后将STIM 1簇正确靶向细胞外周是重要的。STIM 1的C-末端尾部中的聚阳离子区域也有助于STIM 1靶向，但对于CRAC通道激活不是必需的。Orai 1与STIM 1的相互作用需要Orai 1的胞质C末端而不是N末端。我们进一步鉴定了Orai 1的N末端（氨基酸74-90）中的高度保守区域，该区域是CRAC通道开放所必需的。最后，我们发现Orai 1的跨膜结构域参与Orai 1-Orai 1相互作用。
STIM1 and Orai1 are essential components of Ca2+ release-activated Ca2+ channels (CRACs). After endoplasmic reticulum Ca2+ store depletion, STIM1 in the endoplasmic reticulum aggregates and migrates toward the cell periphery to co-localize with Orai1 on the opposing plasma membrane. Little is known about the roles of different domains of STIM1 and Orai1 in protein clustering, migration, interaction, and, ultimately, opening CRAC channels. Here we demonstrate that the coiled-coil domain in the C terminus of STIM1 is crucial for its aggregation. Amino acids 425-671 of STIM1, which contain a serine-proline-rich region, are important for the correct targeting of the STIM1 cluster to the cell periphery after calcium store depletion. The polycationic region in the C-terminal tail of STIM1 also helps STIM1 targeting but is not essential for CRAC channel activation. The cytoplasmic C terminus but not the N terminus of Orai1 is required for its interaction with STIM1. We further identify a highly conserved region in the N terminus of Orai1 (amino acids 74-90) that is necessary for CRAC channel opening. Finally, we show that the transmembrane domain of Orai1 participates in Orai1-Orai1 interactions.