文章基本信息

标题：Retrograde regulation of STIM1-Orai1 interaction and store-operated Ca²⁺ entry by calsequestrin
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作者：Limin Wang ; Lane Zhang ; Shu Li 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2015
卷号：5
DOI：10.1038/srep11349
出版社：Springer Nature
摘要：Interaction between the endoplasmic reticulum (ER)-located stromal interaction molecue1 (STIM1) and the plasma membrane-located Ca²⁺ channel subunit, Orai1, underlies store-operated Ca²⁺ entry (SOCE). Calsequestrin1 (CSQ1), a sarcoplasmic reticulum Ca²⁺ buffering protein, inhibits SOCE, but the mechanism of action is unknown. We identified an interaction between CSQ1 and STIM1 in HEK293 cells. An increase in monomeric CSQ1 induced by depleted Ca²⁺ stores, or trifluoperazine (TFP), a blocker of CSQ folding and aggregation, enhanced the CSQ1-STIM1 interaction. In cells with Ca²⁺ stores depleted, TFP further increased CSQ1 monomerization and CSQ1-STIM1 interaction, but reduced the association of STIM1 with Orai1 and SOCE. Over-expression of CSQ1 or a C-terminal (amino acid 388–396) deletion mutant significantly promoted the association of CSQ1 with STIM1, but suppressed both STIM1-Orai1 interaction and SOCE, while over-expression of the C-terminal (amino acid 362–396) deletion mutant had no effect. The physical interaction between low polymeric forms of CSQ1 and STIM1 likely acts by interfering with STIM1 oligimerization and inhibits STIM1-Orai1 interaction, providing a brake to SOCE under physiological conditions. This novel regulatory mechanism for SOCE may also contribute to the pathological Ca²⁺ overload in calsequestrin deficient diseases, such as malignant hyperthermia and ventricular tachycardia.