Generation of lysophosphatidylinositol by DDHD domain containing 1 (DDHD1): Possible involvement of phospholipase D/phosphatidic acid in the activation of DDHD1
Generation of lysophosphatidylinositol by DDHD domain containing 1 (DDHD1): Possible involvement of phospholipase D/phosphatidic acid in the activation of DDHD1
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DOI：
10.1016/j.bbalip.2010.03.012
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发表时间：
2010-07-01
影响因子：
4.8
通讯作者：
Sugiura, Takayuki
中科院分区：
文献类型：
--
作者：
Yamashita, Atsushi;Kumazawa, Tsukasa;Sugiura, Takayuki
GPR 55是一种七跨膜G蛋白偶联受体，已被提出作为一种新型的大麻素受体。先前，我们鉴定了溶血磷脂酰肌醇（LPI），特别是2-花生四烯酰-LPI，作为GPR 55的激动剂。在本研究中，我们研究了细胞内磷脂酶A1（DDHD结构域包含1，或DDHD 1），以前确定为磷脂酸（PA）偏好PLA 1（PA-PLA 1），是否参与形成2-花生四烯酸-LPI。表达DDHD 1的HEK 293细胞在用[H-3]花生四烯酸预标记并随后被离子霉素激活后产生含[H-3]花生四烯酸的LPI;[H-3]LPI的形成被正丁醇和失活的PLD 1突变体PLD 1 K898 R的过表达抑制。离子霉素处理后，DDHD 1从胞浆转移到细胞膜上。纯化的重组体DDHD 1与[H-3]PI共孵育时形成[H-3]LPI：V-max和表观Km分别为190 μ mol/min/mg蛋白和10mol%PI。DDHD 1与PA结合，PA与DDHD 1的结合增加了对PI的亲和力（K-m：3mol%），并增强了PI-PLA 1活性。DDHD 1被PA激活后，通过其自身的PA水解活性恢复到基础状态。这些结果表明DDHD 1参与了2-花生四烯酸-LPI的形成，并表明该过程受到磷脂酶D释放的PA的调节。在神经母细胞瘤细胞中产生含花生四烯酸的LPI的类似观察表明DDHD 1-LPI-GPR 55轴参与脑中的功能。(C)2010 Elsevier B. V.保留所有权利。
GPR55 is a seven-transmembrane G-protein-coupled receptor that has been proposed as a novel type of cannabinoid receptor. Previously, we identified lysophosphatidylinositol (LPI), in particular 2-arachidonoyl-LPI, as an agonist for GPR55. In the present study, we examined whether intracellular phospholipase A1 (DDHD domain containing 1, or DDHD1), previously identified as phosphatidic acid (PA)-preferring PLA1 (PA-PLA1), is involved in the formation of 2-arachidonoyl-LPI. HEK293 cells expressing DDHD1 produced [H-3]arachidonic acid-containing LPI after prelabeling with [H-3]arachidonic acid and subsequent activation by ionomycin; the formation of [H-3]LPI was inhibited by n-butanol and the overexpression of an inactive PLD1 mutant PLD1K898R. DDHD1 was translocated from the cytosol to membranes upon ionomycin treatment. A purified recombinant DDHD1 formed [H-3]LPI when incubated with [H-3]PI: the V-max and apparent K-m were 190 mu mol/min/mg protein and 10 mol% PI, respectively. DDHD1 binds PA, and the addition of PA to DDHD1 increased the affinity for PI (K-m : 3 mol%) and augmented the PI-PLA1 activity. DDHD1 activated by PA was returned to a basal state by its own PA-hydrolytic activity. These results implicate DDHD1 in the formation of 2-arachidonoyl-LPI and indicate that the process is modulated by PA released by phospholipase D. Similar observations for the production of arachidonic acid-containing LPI in neuroblastoma cells suggest the DDHD1-LPI-GPR55 axis to be involved in functions in the brain. (C) 2010 Elsevier B.V. All rights reserved.