Hosoi Takeshi, Sugikawa Emiko, Chikada Aiko, Koguchi Yutaka, Ohnuki Tetsuo
Discovery Research Laboratories, Tanabe Seiyaku Co. Ltd., 2-50 Kawagishi-2-chome, Toda-shi, Saitama 335-8505, Japan.
Biochem Biophys Res Commun. 2005 Sep 9;334(4):987-95. doi: 10.1016/j.bbrc.2005.06.191.
We have previously identified a Galpha(i/o)-protein-coupled receptor (TG1019/OXE) using 5-oxo-6E,8Z,11Z,14Z-eicosatetraenoic acid (5-oxo-ETE) as its ligand. We investigated signal transduction from TG1019 following stimulation with 5-oxo-ETE and role of TG1019 in 5-oxo-ETE-induced chemotaxis, using Chinese hamster ovary cells expressing TG1019 (CHO/TG1019 cells). 5-Oxo-ETE induced intracellular calcium mobilization and rapid activation of MEK/ERK and PI3K/Akt pathways in CHO/TG1019 cells. CHO/TG1019 cells stimulated with 5-oxo-ETE and other eicosanoids exhibited chemotaxis with efficacies related to agonistic activity of each eicosanoid for TG1019. Pretreatment of the cells with pertussis toxin, a phospholipase C (PLC) inhibitor (U73122) or a PI3K inhibitor (LY294002), markedly suppressed 5-oxo-ETE-induced chemotaxis, whereas pretreatment with a MEK inhibitor (PD98059) had no significant effect on the chemotaxis. Our results show that TG1019 mediates 5-oxo-ETE-induced chemotaxis and that signals from TG1019 are transduced via Galpha(i/o) protein to PLC/calcium mobilization, MEK/ERK, and PI3K/Akt, among which PLC and PI3K would play important roles in the chemotaxis.
我们之前已鉴定出一种Gα(i/o)蛋白偶联受体（TG1019/OXE），其配体为5-氧代-6E,8Z,11Z,14Z-二十碳四烯酸（5-氧代-ETE）。我们使用表达TG1019的中国仓鼠卵巢细胞（CHO/TG1019细胞），研究了用5-氧代-ETE刺激后TG1019的信号转导以及TG1019在5-氧代-ETE诱导的趋化作用中的作用。5-氧代-ETE可诱导CHO/TG1019细胞内钙动员以及MEK/ERK和PI3K/Akt信号通路的快速激活。用5-氧代-ETE和其他类花生酸刺激的CHO/TG1019细胞表现出趋化作用，其效力与每种类花生酸对TG1019的激动活性相关。用百日咳毒素、磷脂酶C（PLC）抑制剂（U73122）或PI3K抑制剂（LY294002）对细胞进行预处理，可显著抑制5-氧代-ETE诱导的趋化作用，而用MEK抑制剂（PD98059）预处理对趋化作用无显著影响。我们的结果表明，TG1019介导5-氧代-ETE诱导的趋化作用，并且来自TG1019的信号通过Gα(i/o)蛋白转导至PLC/钙动员、MEK/ERK和PI3K/Akt，其中PLC和PI3K在趋化作用中起重要作用。
