Orci Lelio, Ravazzola Mariella, Le Coadic Marion, Shen Wei-Wei, Demaurex Nicolas, Cosson Pierre
Department of Cell Physiology and Metabolism, University of Geneva Medical School, 1211 Geneva 4, Switzerland.
Proc Natl Acad Sci U S A. 2009 Nov 17;106(46):19358-62. doi: 10.1073/pnas.0911280106. Epub 2009 Nov 11.
Store-operated calcium entry relies on the formation of a specialized compartment derived from the endoplasmic reticulum (ER) and closely apposed to the plasma membrane. In this study, detailed ultrastructural analysis revealed the existence of three distinct structures derived from conventional ER: precortical ER, cortical ER, and thin cortical ER. Precortical subdomains of the ER enriched in STIM1 can form without contacting the plasma membrane. Upon ER calcium depletion, these subdomains are translocated to the plasma membrane to form cortical ER, which is still connected to the conventional ER. Thin cortical ER, depleted of BiP and deprived of attached ribosomes, may represent a specialized region dedicated to calcium regulation and not engaged in protein translocation and folding. These observations form the basis for future structure-function analysis of cortical ER.
储存式钙内流依赖于源自内质网（ER）并紧邻质膜形成的一个特殊区室。在本研究中，详细的超微结构分析揭示了源自传统内质网的三种不同结构的存在：前皮质内质网、皮质内质网和薄皮质内质网。富含STIM1的内质网前皮质亚结构域可在不接触质膜的情况下形成。在内质网钙耗竭时，这些亚结构域会转移至质膜形成皮质内质网，其仍与传统内质网相连。薄皮质内质网缺乏BiP且没有附着核糖体，可能代表一个专门用于钙调节而不参与蛋白质转运和折叠的特殊区域。这些观察结果构成了未来对皮质内质网进行结构 - 功能分析的基础。
