Release of calcium from endolysosomes increases calcium influx through N-type calcium channels: Evidence for acidic store-operated calcium entry in neurons.
Release of calcium from endolysosomes increases calcium influx through N-type calcium channels: Evidence for acidic store-operated calcium entry in neurons.
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DOI：
10.1016/j.ceca.2015.10.001
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发表时间：
2015-12
期刊：
影响因子：
4
通讯作者：
Chen X
中科院分区：
文献类型：
--
作者：
Hui L;Geiger NH;Bloor-Young D;Churchill GC;Geiger JD;Chen X
神经元具有复杂的内溶酶体系统。最近，内溶酶体被发现具有容易释放的细胞内钙储存;然而，关于这种“酸性钙储存”如何影响神经元中的钙信号传导，相对知之甚少。在这里，我们证明了在原代培养的神经元中，从酸性钙库释放的钙触发了跨质膜的钙内流，我们称之为“酸性钙库操作的钙进入（aSOCE）”的现象。aSOCE在功能上不同于涉及内质网的钙库操作的钙释放和钙进入。aSOCE似乎受N型钙通道（NTCC）控制，因为通过选择性阻断NTCC或通过siRNA敲低NTCC显著减弱aSOCE。此外，我们证明了NTCC与溶酶体相关膜蛋白1（LAMP 1）共免疫沉淀，并且aSOCE伴随着NTCC和LAMP 1蛋白的细胞表面表达水平增加。此外，我们证明了siRNA敲低LAMP 1或Rab 27 a，这两者都是参与溶酶体胞吐的关键蛋白，显著减弱了aSOCE。总之，我们的数据表明，aSOCE发生在神经元中，aSOCE在调节神经元内钙的水平和作用中起着重要作用，并且aSOCE至少部分地由N型钙通道通过LAMP 1依赖性溶酶体胞吐作用外吞插入质膜来调节。
Neurons possess an elaborate system of endolysosomes. Recently, endolysosomes were found to have readily releasable stores of intracellular calcium; however, relatively little is known about how such ‘acidic calcium stores’ affect calcium signaling in neurons. Here we demonstrated in primary cultured neurons that calcium released from acidic calcium stores triggered calcium influx across the plasma membrane, a phenomenon we have termed “acidic store-operated calcium entry (aSOCE)”. aSOCE was functionally distinct from store-operated calcium release and calcium entry involving endoplasmic reticulum. aSOCE appeared to be governed by N-type calcium channels (NTCCs) because aSOCE was attenuated significantly by selectively blocking NTCCs or by siRNA knockdown of NTCCs. Furthermore, we demonstrated that NTCCs co-immunoprecipitated with the lysosome associated membrane protein 1 (LAMP1), and that aSOCE is accompanied by increased cell-surface expression levels of NTCC and LAMP1 proteins. Moreover, we demonstrated that siRNA knockdown of LAMP1 or Rab27a, both of which are key proteins involved in lysosome exocytosis, attenuated significantly aSOCE. Taken together our data suggest that aSOCE occurs in neurons, that aSOCE plays an important role in regulating the levels and actions of intraneuronal calcium, and that aSOCE is regulated at least in part by exocytotic insertion of N-type calcium channels into plasma membranes through LAMP1-dependent lysosome exocytosis.