An aromatic amino acid in the coiled-coil 1 domain plays a crucial role in the auto-inhibitory mechanism of STIM1.
An aromatic amino acid in the coiled-coil 1 domain plays a crucial role in the auto-inhibitory mechanism of STIM1.
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DOI：
10.1042/bj20130292
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发表时间：
2013-09
期刊：
影响因子：
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通讯作者：
Jun-wei Yu;Haining Zhang;Mingshu Zhang;Yongqiang Deng;Huiyu Wang;Jingze Lu;Tao Xu;P. Xu
中科院分区：
文献类型：
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作者：
Jun-wei Yu;Haining Zhang;Mingshu Zhang;Yongqiang Deng;Huiyu Wang;Jingze Lu;Tao Xu;P. Xu
STIM 1（基质相互作用分子1）是介导免疫和非兴奋细胞中通过CRAC（钙释放激活的钙通道）储存操作的钙离子进入的关键元件之一。在生理条件下，STIM 1 C-和STIM 1 N-末端的分子内自抑制在保持STIM 1处于失活状态中起重要作用。然而，STIM 1 C末端的自抑制机制仍不清楚。在本研究中，我们首先预测了一个短的抑制结构域（残基310-317）在人类的STIM 1，可能会决定不同的定位人类的STIM 1从秀丽隐杆线虫STIM 1在静息细胞。接下来，我们证实了这一预测，并进一步鉴定了一个芳香族氨基酸残基Tyr³ ¹，它在维持静止细胞中STIM 1的闭合构象中起着至关重要的作用。全长STIM 1-Y316 A在质膜附近形成组成性簇，并在与Orai 1共表达时在静息状态下激活CRAC通道。Y316 A突变的引入导致体外纯化的STIM 1片段发生了更高级的寡聚化，提示STIM 1 C端的Tyr 316 A残基可能参与了STIM 1 C端在静止状态下的自抑制机制。这种抑制可以通过使用氢键和/或疏水键与CAD相互作用或通过使用排斥力的分子间相互作用来实现，这维持了二聚体STIM 1。
STIM1 (stromal interaction molecule 1) is one of the key elements that mediate store-operated Ca²⁺ entry via CRAC (Ca²⁺- release-activated Ca²⁺) channels in immune and non-excitable cells. Under physiological conditions, the intramolecular auto-inhibitions in STIM1 C- and STIM1 N-termini play essential roles in keeping STIM1 in an inactive state. However, the auto-inhibitory mechanism of the STIM1 C-terminus is still unclear. In the present study, we first predicted a short inhibitory domain (residues 310-317) in human STIM1 that might determine the different localizations of human STIM1 from Caenorhabditis elegans STIM1 in resting cells. Next, we confirmed the prediction and further identified an aromatic amino acid residue, Tyr³¹⁶, that played a crucial role in maintaining STIM1 in a closed conformation in quiescent cells. Full-length STIM1-Y316A formed constitutive clusters near the plasma membrane and activated the CRAC channel in the resting state when co-expressed with Orai1. The introduction of a Y316A mutation caused the higher-order oligomerization of the in vitro purified STIM1 fragment containing both the auto-inhibitory domain and CAD(CRAC-activating domain).We propose that the Tyr³¹⁶ residue may be involved in the auto-inhibitory mechanism of the STIM1 C-terminus in the quiescent state. This inhibition could be achieved either by interacting with the CAD using hydrogen and/or hydrophobic bonds, or by an intermolecular interaction using repulsive forces, which maintained a dimeric STIM1.