A G-protein-coupled receptor for leukotriene B-4 that mediates chemotaxis
A G-protein-coupled receptor for leukotriene B-4 that mediates chemotaxis
复制标题
DOI：
10.1038/42506
复制
发表时间：
1997-06-05
期刊：
影响因子：
64.8
通讯作者：
Shimizu, T
中科院分区：
文献类型：
--
作者：
Yokomizo, T;Izumi, T;Shimizu, T
白三烯B-4 (LTB4)(1)是一种有效的化学引诱剂，主要参与炎症、免疫反应和宿主防御感染(2)。LTB4通过结合其细胞表面受体（BLTR）激活炎症细胞(3)。LTB4还可以结合并激活核内转录因子PPAR α，从而激活终止炎症过程的基因(4)。在这里，我们报告了克隆的互补DNA编码细胞表面LTB4受体，在人类白细胞中高度表达。采用减法方法，从维甲酸分化的HL-60细胞中分离出两个cDNA克隆（HL-1和HL-5）。这两个克隆含有相同的开放阅读框，编码一个352个氨基酸的蛋白质，预计包含7个膜跨越结构域，但不同的5'-未翻译区域。用含有HL-5开放阅读框的表达构建体转染的Cos-7细胞的膜组分显示出特异性的LTB4结合，其K-d （0.154 nM）与维甲酸分化的HL-60细胞相当。在稳定表达该受体的CHO细胞中，LTB4诱导细胞内钙、d -肌醇-1,4,5-三磷酸（InsP(3)）积累增加，并抑制腺苷酸环化酶。此外，表达外源性BLTR的CHO细胞以百日咳毒素敏感的方式对低浓度LTB4表现出明显的趋化反应。我们的发现，连同先前的报道（4,5），表明LTB4是一种独特的脂质介质，可与细胞表面和核受体相互作用。
Leukotriene B-4 (LTB4)(1) is a potent chemoattractant that is primarily involved in inflammation, immune responses and host defence against infection(2). LTB4 activates inflammatory cells by binding to its cell-surface receptor (BLTR)(3). LTB4 can also bind and activate the intranuclear transcription factor PPAR alpha, resulting in the activation of genes that terminate inflammatory processess(4). Here we report the cloning of the complementary DNA encoding a cell-surface LTB4 receptor that is highly expressed in human leukocytes. Using a subtraction strategy, we isolated two cDNA clones (HL-1 and HL-5) from retinoic acid-differentiated HL-60 cells. These two clones contain identical open reading frames encoding a protein of 352 amino acids and predicted to contain seven membrane-spanning domains, but different 5'-untranslated regions. Membrane fractions of Cos-7 cells transfected with an expression construct containing the open reading frame of HL-5 showed specific LTB4 binding, with a K-d (0.154 nM) comparable to that observed in retinoic acid-differentiated HL-60 cells. In CHO cells stably expressing this receptor, LTB4 induced increases in intracellular calcium, D-myo-inositol-1,4,5-triphosphate (InsP(3)) accumulation, and inhibition of adenlyl cyclase. Furthermore, CHO cells expressing exogenous BLTR showed marked chemotactic responses towards low concentrations of LTB4 in a pertussis-toxin-sensitive manner. Our findings, together with previous reports(4,5), show that LTB4 is a unique lipid mediator that interacts with both cell-surface and nuclear receptors.