EFHB is a Novel Cytosolic Ca2+ Sensor That Modulates STIM1-SARAF Interaction
EFHB is a Novel Cytosolic Ca2+ Sensor That Modulates STIM1-SARAF Interaction
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DOI：
10.1159/000495494
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发表时间：
2018-01-01
影响因子：
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通讯作者：
Rosado, Juan A.
中科院分区：
文献类型：
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作者：
Albarran, Letizia;Lopez, Jose J.;Rosado, Juan A.
背景/目的：STIM1和Orai1是钙离子通道的重要组成部分。在参与SOCE调节的蛋白质中，Saraf阻止SOCE的自发激活并调节STIM1的功能。方法：用荧光倒置显微镜观察Fura-2负载细胞内钙离子的变化。免疫沉淀法和免疫印迹法检测STIM1与Orai1、EFHB(EF-Hand结构域家族成员B，也称为CFAP21)和SARAF的相互作用。共聚焦显微镜观察EFHB参与NFAT向胞核的移位。结果：我们报道了EFHB作为一种新的SOCE调节剂的鉴定。EFHB在储存耗尽时与STIM1相互作用，并通过钙(2+)依赖的机制解离。RNAi介导的沉默和过表达研究表明，EFHB在STIM1和Orai1的相互作用、SOCE的激活和NFAT从胞浆到细胞核的移位中起着相关的作用。沉默EFHB的表达可阻断SARAF和STIM1的解离，这表明EFHB可能在两者之间的动态相互作用中发挥重要作用，这与钙耗竭时Orai1通道的激活以及随后通过缓慢的钙依赖失活来调节Orai1通道有关。结论：EFHB是一种新的调节STIM1-Saraf相互作用的SOCE调节剂。(C)2018年作者(S)由S.Karger AG，巴塞尔出版
Background/Aims: STIM1 and Orai1 are the key components of store-operated Ca2+ entry (SOCE). Among the proteins involved in the regulation of SOCE, SARAF prevents spontaneous activation of SOCE and modulates STIM1 function. Methods: Cytosolic Ca2+ mobilization was estimated in fura-2-loaded cells using an epifluorescence inverted microscope. STIM1 interaction with Orai1, EFHB (EF-hand domain family member B, also known as CFAP21) and SARAF was detected by immunoprecipitation followed by Western blotting using specific antibodies. The involvement of EFHB in the translocation of NFAT to the nucleus was detected by confocal microscopy. Results: Here, we report the identification of EFHB as a new SOCE regulator. EFHB interacts with STIM1 upon store depletion and dissociates through a Ca(2+)dependent mechanism. RNAi-mediated silencing as well as overexpression studies revealed that EFHB plays a relevant role in the interaction of STIM1 and Orai1 upon store depletion, the activation of SOCE and NFAT translocation from the cytosol to the nucleus. Silencing EFHB expression abolished the dissociation of SARAF from STIM1, which indicates that EFHB might play an important role in the dynamic interaction between both proteins, which is relevant for the activation of Orai1 channels upon Ca2+ store depletion and their subsequent modulation via slow Ca2+-dependent inactivation. Conclusion: Our results indicate that EFHB is a new SOCE regulator that modulates STIM1-SARAF interaction. (C) 2018 The Author(s) Published by S. Karger AG, Basel