Activation of the mitogen-activated protein kinase/cytosolic phospholipase A2 pathway in a rat mast cell line. Indications of different pathways for release of arachidonic acid and secretory granules.
Activation of the mitogen-activated protein kinase/cytosolic phospholipase A2 pathway in a rat mast cell line. Indications of different pathways for release of arachidonic acid and secretory granules.
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DOI：
10.4049/jimmunol.154.10.5391
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发表时间：
1995-05
影响因子：
4.4
通讯作者：
N. Hirasawa;F. Santini;M. Beaven
中科院分区：
文献类型：
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作者：
N. Hirasawa;F. Santini;M. Beaven
在表达天然Fc β R1和G蛋白偶联毒蕈碱m1受体的突变肥大细胞（RBL-2 H3（m1））系中，研究了有丝分裂原活化蛋白（MAP）激酶在花生四烯酸释放中的作用。用Ag、卡巴胆碱、Ca（2+）-离子载体或毒胡萝卜素刺激这些细胞，导致Raf 1、MEK 1、p42 mapk MAP激酶和最近克隆的胞质磷脂酶A2（PLA 2）磷酸化，MAP激酶和PLA 2的活性增加，以及花生四烯酸的释放。由于这种级联反应被鸟苷5 '-（2-硫代二磷酸）抑制，因此它似乎依赖于GTP结合蛋白。然而，这些反应，是不依赖于蛋白激酶C的级联反应是完全耐选择性蛋白激酶C抑制剂，Ro 31 -7549的行动，而释放的分泌颗粒标记，氨基己糖苷酶，被这种代理商。花生四烯酸和氨基己糖苷酶释放的刺激途径之间的差异也明显来自激酶抑制剂槲皮素的影响。上述级联反应，包括花生四烯酸的释放，约5 μ M槲皮素抑制50%，而分泌仅在较高浓度的抑制剂抑制。此外，抑制MAP激酶的激活和花生四烯酸的释放密切相关。这一发现和以前的研究结果表明，花生四烯酸的释放归因于MAP激酶（用于激活PLA 2）和Ca 2+（用于PLA 2与膜的结合）对胞浆PLA 2的调节，而氨基己糖苷酶的释放主要受Ca 2+和蛋白激酶C的调节。
The role of mitogen-activated protein (MAP) kinase in the release of arachidonic acid was examined in a mutated mast cell (RBL-2H3(m1)) line that expressed both native Fc epsilon R1 and the G protein-coupled muscarinic m1 receptor. Stimulation of these cells with Ag, carbachol, Ca(2+)-ionophore, or thapsigargin resulted in the phosphorylation of Raf1, MEK1, p42mapk MAP kinase, and the recently cloned cytosolic phospholipase A2 (PLA2) and increased activities of both MAP kinase and PLA2, as well as release of arachidonic acid. Because this cascade of reactions was inhibited by guanosine 5'-(2-thiodiphosphate), it appeared to be dependent on a GTP-binding protein(s). These reactions, however, were not dependent on protein kinase C; the cascade was totally resistant to the actions of a selective protein kinase C inhibitor, Ro31-7549, whereas release of the secretory granule marker, hexosaminidase, was blocked by this agent. Differences between the stimulatory pathways for release of arachidonic acid and hexosaminidase were evident also from the effects of the kinase inhibitor, quercetin. The above cascade of reactions, including release of arachidonic acid, was inhibited by 50% with approximately 5 microM quercetin, whereas secretion was inhibited only at higher concentrations of inhibitor. Moreover, inhibition of the activation of MAP kinase and release of arachidonic acid were closely correlated. This and previous findings suggested that release of arachidonic acid was attributable to the regulation of cytosolic PLA2 by MAP kinase (for activation of PLA2) and Ca2+ (for association of PLA2 with the membrane), whereas release of hexosaminidase was regulated primarily by Ca2+ and protein kinase C.