Lang J, Boulay F, Li G, Wollheim C B
Département de Médecine, Université de Genéve, Switzerland.
EMBO J. 1993 Jul;12(7):2671-9. doi: 10.1002/j.1460-2075.1993.tb05928.x.
In neutrophils fMet-Leu-Phe activates phospholipase C via a pertussis toxin sensitive G-protein and induces granule secretion. We have transfected a human cDNA sequence encoding the fMet-Leu-Phe receptor into the insulin secreting cell line RINm5F to study receptor-effector coupling with special regard to secretion. Stable overexpression resulted in membrane hyperpolarization, reduction of cAMP accumulation and inhibition of insulin secretion upon exposure of cells to fMet-Leu-Phe with EC50 values in the pmol range. As in the neutrophil, nanomolar concentrations of ligand induced membrane depolarization and activation of phospholipase C, with subsequent mobilization and influx of calcium. In permeabilized cells the inhibitory effect of fMet-Leu-Phe on secretion was partially retained indicating a direct action of the fMet-Leu-Phe receptor on exocytosis. Pertussis toxin abolished the effects of fMet-Leu-Phe. Our results suggest conserved coupling from fMet-Leu-Phe receptor to pertussis toxin sensitive transducers analogous to the mechanism in neutrophils. However, the net biological effect of receptor activation is determined by additional factors intrinsic to the host cell.
在中性粒细胞中，甲酰甲硫氨酰 - 亮氨酰 - 苯丙氨酸（fMet-Leu-Phe）通过一种对百日咳毒素敏感的G蛋白激活磷脂酶C，并诱导颗粒分泌。我们已将编码fMet-Leu-Phe受体的人类cDNA序列转染到胰岛素分泌细胞系RINm5F中，以研究受体 - 效应器偶联，特别关注分泌情况。稳定的过表达导致细胞膜超极化、cAMP积累减少以及细胞暴露于fMet-Leu-Phe时胰岛素分泌受到抑制，其半数有效浓度（EC50）值在皮摩尔范围内。与中性粒细胞中一样，纳摩尔浓度的配体诱导细胞膜去极化和磷脂酶C的激活，随后钙动员和内流。在透化细胞中，fMet-Leu-Phe对分泌的抑制作用部分得以保留，这表明fMet-Leu-Phe受体对胞吐作用有直接作用。百日咳毒素消除了fMet-Leu-Phe的作用。我们的结果表明，从fMet-Leu-Phe受体到对百日咳毒素敏感的转导器的偶联是保守的，类似于中性粒细胞中的机制。然而，受体激活的净生物学效应由宿主细胞固有的其他因素决定。
