E-syt1 Re-arranges STIM1 Clusters to Stabilize Ring-shaped ER-PM Contact Sites and Accelerate Ca2+ Store Replenishment
E-syt1 Re-arranges STIM1 Clusters to Stabilize Ring-shaped ER-PM Contact Sites and Accelerate Ca2+ Store Replenishment
复制标题
E-syt1 重新排列 STIM1 簇以稳定环形 ER-PM 接触位点并加速 Ca2 存储补充
DOI：
10.1038/s41598-019-40331-0
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发表时间：
2019-03-08
影响因子：
4.6
通讯作者：
Chen, Liangyi
中科院分区：
文献类型：
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作者：
Kang, Fei;Zhou, Mengxuan;Chen, Liangyi
在许多非兴奋性细胞中，内质网 (ER) Ca2+ 储存的消耗导致 ER 和质膜 (PM) 之间膜接触位点 (MCS) 的动态形成，从而激活储存操作的 Ca2+ 进入 (SOCE) 以重新填充 ER 储存。两种不同的 Ca2+ 敏感蛋白 STIM1 和扩展突触结合蛋白 1 (E-syt1) 在此过程中被激活。由于缺乏活细胞超分辨率成像，STIM1和E-syt1在ER Ca2+储备耗尽和补充过程中如何动态协调MCS仍不清楚。利用自制的超分辨率显微镜，在活细胞中提供卓越的轴向和横向分辨率，我们发现细胞外 Ca2+ 通过 SOCE 流入激活 E-syt1，向 PM 移动约 12 nm。出乎意料的是，激活的E-syt1本身并不构成MCS，而是将邻近的ER结构重新排列成包围E-syt1斑点的环形MCS（直径230~280 nm），这有助于稳定MCS并加速局部ER Ca2+补充。总体而言，我们证明了 STIM1 和 E-syt1 在 MCS 形成调节、SOCE 激活和 ER Ca2+ 储备补充中的不同作用。
In many non-excitable cells, the depletion of endoplasmic reticulum (ER) Ca2+ stores leads to the dynamic formation of membrane contact sites (MCSs) between the ER and the plasma membrane (PM), which activates the store-operated Ca2+ entry (SOCE) to refill the ER store. Two different Ca2+-sensitive proteins, STIM1 and extended synaptotagmin-1 (E-syt1), are activated during this process. Due to the lack of live cell super-resolution imaging, how MCSs are dynamically regulated by STIM1 and E-syt1 coordinately during ER Ca2+ store depletion and replenishment remain unknown. With home-built super-resolution microscopes that provide superior axial and lateral resolution in live cells, we revealed that extracellular Ca2+ influx via SOCE activated E-syt1s to move towards the PM by ~12 nm. Unexpectedly, activated E-syt1s did not constitute the MCSs per se, but re-arranged neighboring ER structures into ring-shaped MCSs (230~280 nm in diameter) enclosing E-syt1 puncta, which helped to stabilize MCSs and accelerate local ER Ca2+ replenishment. Overall, we have demonstrated different roles of STIM1 and E-syt1 in MCS formation regulation, SOCE activation and ER Ca2+ store replenishment.