The Sigma-2 Receptor and Progesterone Receptor Membrane Component 1 are Different Binding Sites Derived From Independent Genes.
The Sigma-2 Receptor and Progesterone Receptor Membrane Component 1 are Different Binding Sites Derived From Independent Genes.
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DOI：
10.1016/j.ebiom.2015.10.017
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发表时间：
2015-11
期刊：
影响因子：
11.1
通讯作者：
Ruoho AE
中科院分区：
文献类型：
--
作者：
Chu UB;Mavlyutov TA;Chu ML;Yang H;Schulman A;Mesangeau C;McCurdy CR;Guo LW;Ruoho AE
sigma-2受体（S2R）是癌症和神经疾病的潜在治疗靶点。然而，S2R的身份仍然是一个有争议的问题。从历史上看，S2R被定义为：(1)与1,3-二-邻甲基胍（DTG）和氟哌啶醇具有高亲和力的结合位点，但与选择性sigma-1受体配体(+)-戊唑嗪没有亲和力；(2)18-21 kDa的蛋白质，通过与[3H]-Azido-DTG和[125I]-碘azido- fenproporph （[125I]-IAF）的特异性光标记显示。最近，黄体酮受体膜组分1 （PGRMC1）是一种25 kDa的蛋白，被报道为S2R （Nature Communications, 2011,2:380）。为了证实这一鉴定，我们使用CRISPR/Cas9技术创建了PGRMC1敲除的NSC34细胞系。我们发现，在缺乏或过表达PGRMC1的NSC34细胞中，S2R的最大[3H]-DTG结合（Bmax）以及S2R的dtg保护[125I]-IAF光标记与野生型对照细胞相似。此外，DTG和氟哌啶醇对PGRMC1的亲和力（KI分别为472 μM和350 μM），与[3H]-孕酮竞争，比S2R （20-80 nM）低3个数量级以上。这些结果表明PGRMC1和S2R是不同基因表达的不同结合位点。sigma-2受体是一个重要的药物靶点，但其分子特性一直是争论的热点。最近有报道称PGRMC1是sigma-2的结合位点（Nature Communications, 2011,2:380）。我们的数据表明，PGRMC1和sigma-2受体是不同基因表达的不同结合位点。sigma-2受体（S2R）是癌症和神经疾病的潜在重要治疗靶点，但其基因身份长期以来一直是一个谜。虽然最近的一份重要报告得出结论，孕激素结合蛋白（PGRMC1）是sigma-2受体，但缺少关键的决定性证据。我们使用基因组编辑技术结合化学生物学和药理学测定重新验证了这一结论。明确的结果表明，PGRMC1不是最初定义的真正的sigma-2受体。该研究可能通过指导未来发现sigma-2药物结合位点的真实身份而有益于公众健康。
The sigma-2 receptor (S2R) is a potential therapeutic target for cancer and neuronal diseases. However, the identity of the S2R has remained a matter of debate. Historically, the S2R has been defined as (1) a binding site with high affinity to 1,3-di-o-tolylguanidine (DTG) and haloperidol but not to the selective sigma-1 receptor ligand (+)-pentazocine, and (2) a protein of 18–21 kDa, as shown by specific photolabeling with [3H]-Azido-DTG and [125I]-iodoazido-fenpropimorph ([125I]-IAF). Recently, the progesterone receptor membrane component 1 (PGRMC1), a 25 kDa protein, was reported to be the S2R (Nature Communications, 2011, 2:380). To confirm this identification, we created PGRMC1 knockout NSC34 cell lines using the CRISPR/Cas9 technology. We found that in NSC34 cells devoid of or overexpressing PGRMC1, the maximum [3H]-DTG binding to the S2R (Bmax) as well as the DTG-protectable [125I]-IAF photolabeling of the S2R were similar to those of wild-type control cells. Furthermore, the affinities of DTG and haloperidol for PGRMC1 (KI = 472 μM and 350 μM, respectively), as determined in competition with [3H]-progesterone, were more than 3 orders of magnitude lower than those reported for the S2R (20–80 nM). These results clarify that PGRMC1 and the S2R are distinct binding sites expressed by different genes. The sigma-2 receptor is an important drug target but its molecular identity has remained a hot topic of debate. PGRMC1 has recently been reported to be the sigma-2 binding site (Nature Communications, 2011, 2:380). Our data clarify that PGRMC1 and the sigma-2 receptor are distinct binding sites expressed by different genes. The sigma-2 receptor (S2R) is a potential important therapeutic target for cancer and neuronal diseases, yet its gene identity is a long-held mystery. While a recent prominent report concluded that a progesterone-binding protein (PGRMC1) is the sigma-2 receptor, the critical defining evidence was missing. We re-tested this conclusion using a genome-editing technology combined with chemical biology and pharmacological determinations. The unambiguous results indicate that PGRMC1 is not the originally defined true sigma-2 receptor. This study may benefit public health by guiding future discovery of the true identity of the sigma-2 drug binding site.