Association of the IP3R to STIM1 provides a reduced intraluminal calcium microenvironment, resulting in enhanced store-operated calcium entry.
Association of the IP3R to STIM1 provides a reduced intraluminal calcium microenvironment, resulting in enhanced store-operated calcium entry.
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DOI：
10.1038/s41598-018-31621-0
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发表时间：
2018-09-05
影响因子：
4.6
通讯作者：
Vaca L
中科院分区：
文献类型：
--
作者：
Sampieri A;Santoyo K;Asanov A;Vaca L
三磷酸肌醇受体(IP3R)参与调控钙离子内流(SOCE)的研究已有多年。然而，到目前为止，导致这种观察的分子机制还没有被阐明。在本研究中，我们发现IP3R通过G蛋白偶联受体激活三磷酸肌醇信号通路，在内质网(ER)耗竭时与STIM1结合。IP3R-STIM1联合导致STIM1斑点形成增加，Orai介导的全细胞电流增加，钙内流增加。用钙ATPase抑制剂(thapsigargin，TG)耗尽内质网不能诱导IP3R-STIM1结合，表明这种结合需要活性的IP3R。FRET实验和免疫共沉淀实验证明，只有在IP3R激活后才能观察到IP3R-STIM1的结合。用MAG-Fluo-4测定内质网内钙离子显示，当IP3R过表达时，细胞内钙离子消耗增加。STIM1-GCaMP融合蛋白表明，当IP3R过表达时，STIM1在其EF-Hand结构域附近检测到较低的钙浓度，与均匀分布在内质网腔中的GCaMP(ER-GCaMP)报告的荧光相比。所有这些数据有力地表明，三磷酸肌醇信号级联的激活诱导了IP3R-STIM1复合体的形成。激活的IP3R在STIM1附近提供了一个减少的腔内钙微环境，导致Orai电流和SOCE的激活增强。
The involvement of inositol trisphosphate receptor (IP3R) in modulating store-operated calcium entry (SOCE) was established many years ago. Nevertheless, the molecular mechanism responsible for this observation has not been elucidated to this date. In the present study we show that IP3R associates to STIM1 upon depletion of the endoplasmic reticulum (ER) by activation of the inositol trisphosphate signaling cascade via G-protein coupled receptors. IP3R-STIM1 association results in enhanced STIM1 puncta formation and larger Orai-mediated whole-cell currents as well as increased calcium influx. Depleting the ER with a calcium ATPase inhibitor (thapsigargin, TG) does not induce IP3R-STIM1 association, indicating that this association requires an active IP3R. The IP3R-STIM1 association is only observed after IP3R activation, as evidenced by FRET experiments and co-immunoprecipitation assays. ER intraluminal calcium measurements using Mag-Fluo-4 showed enhanced calcium depletion when IP3R is overexpressed. A STIM1-GCaMP fusion protein indicates that STIM1 detects lower calcium concentrations near its EF-hand domain when IP3R is overexpressed when compared with the fluorescence reported by a GCaMP homogenously distributed in the ER lumen (ER-GCaMP). All these data together strongly suggest that activation of inositol trisphosphate signaling cascade induces the formation of the IP3R-STIM1 complex. The activated IP3R provides a reduced intraluminal calcium microenvironment near STIM1, resulting in enhanced activation of Orai currents and SOCE.
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影响因子：
16.6
作者：
Thillaiappan NB;Chavda AP;Tovey SC;Prole DL;Taylor CW
通讯作者：
Taylor CW
影响因子：
3.7
作者：
Henderson MJ;Baldwin HA;Werley CA;Boccardo S;Whitaker LR;Yan X;Holt GT;Schreiter ER;Looger LL;Cohen AE;Kim DS;Harvey BK
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影响因子：
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作者：
Alicia, Sampieri;Angelica, Zepeda;Vaca, Luis
通讯作者：
Vaca, Luis
影响因子：
4
作者：
Moreno, Claudia;Sampieri, Alicia;Vaca, Luis
通讯作者：
Vaca, Luis
DOI：
10.1016/j.bbamcr.2015.01.019
发表时间：
2015-09-01
影响因子：
5.1
作者：
Majewski, Lukasz;Kuznicki, Jacek
通讯作者：
Kuznicki, Jacek