Rudolf Schönheimer Institute of Biochemistry, Medical Faculty, University of Leipzig, 04103, Leipzig, Germany.
Department of Biochemistry, Chemistry and Pharmacology, Vanderbilt Institute of Chemical Biology, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN, 37232-0146, USA.
Sci Rep. 2017 May 24;7(1):2380. doi: 10.1038/s41598-017-02414-8.
Cyclooxygenase-2 catalyses the biosynthesis of prostaglandins from arachidonic acid but also the biosynthesis of prostaglandin glycerol esters (PG-Gs) from 2-arachidonoylglycerol. Previous studies identified PG-Gs as signalling molecules involved in inflammation. Thus, the glyceryl ester of prostaglandin E, PGE-G, mobilizes Ca and activates protein kinase C and ERK, suggesting the involvement of a G protein-coupled receptor (GPCR). To identify the endogenous receptor for PGE-G, we performed a subtractive screening approach where mRNA from PGE-G response-positive and -negative cell lines was subjected to transcriptome-wide RNA sequencing analysis. We found several GPCRs that are only expressed in the PGE-G responder cell lines. Using a set of functional readouts in heterologous and endogenous expression systems, we identified the UDP receptor P2Y as the specific target of PGE-G. We show that PGE-G and UDP are both agonists at P2Y, but they activate the receptor with extremely different EC values of ~1 pM and ~50 nM, respectively. The identification of the PGE-G/P2Y pair uncovers the signalling mode of PG-Gs as previously under-appreciated products of cyclooxygenase-2.
环氧化酶-2催化花生四烯酸合成前列腺素，但也催化 2-花生四烯酰甘油合成前列腺素甘油酯 (PG-Gs)。先前的研究表明 PG-Gs 是参与炎症的信号分子。因此，前列腺素 E 的甘油酯，PGE-G，动员 Ca 并激活蛋白激酶 C 和 ERK，表明涉及 G 蛋白偶联受体 (GPCR)。为了鉴定 PGE-G 的内源性受体，我们进行了一种减法筛选方法，其中来自 PGE-G 反应阳性和阴性细胞系的 mRNA 进行了转录组范围的 RNA 测序分析。我们发现了几种仅在 PGE-G 应答细胞系中表达的 GPCR。使用异源和内源性表达系统中的一组功能读数，我们鉴定出 UDP 受体 P2Y 是 PGE-G 的特异性靶标。我们表明，PGE-G 和 UDP 都是 P2Y 的激动剂，但它们以极其不同的 EC 值激活受体，分别约为 1 pM 和 50 nM。PGE-G/P2Y 对的鉴定揭示了 PG-Gs 的信号模式，此前对其认识不足，认为它是环氧化酶-2 的产物。
