Effects of chymase on limited proteolysis and activation of protein kinase on the mechanism of degranulation from mast cells

两种类型的丝氨酸蛋白质，如chymase和tryptase，将其定位在大细胞的grnules中。我们发现了一种从大鼠肥大细胞中提取的霉菌抗体、衍生模拟和特定抑制剂的霉菌抑制剂，但它的抑制剂不是tryptase抑制剂。在染色体和抗染色体F（ab'）的特定抑制剂中，也有蛋白激酶C与IgE受体结合后被抑制的蛋白磷酸化。从这些结果中，我们推测了CHUMAASE激活蛋白激酶C在退化过程中的作用。在退化后， Chymase保留在Mast Cell的表面。如果要澄清颗粒或细胞表面上的子宫被释放在组胺释放中，我们测试了组胺释放和组胺两种抑制剂的内部蜂窝本地化，例如反子宫f（ab'）_2和^<125>I-Bowman Burk大豆抑制剂。在这些抑制剂在37 ° C被大量细胞孵化后，它们首先被绑定到被大量细胞的等离子体膜，然后被吸收到颗粒时间上，在抑制剂中释放组胺后在IgE受体桥接的抑制剂。当这些抑制剂在4 ° C处被吸收细胞时，它们将被绑定到等离子体膜，但没有被吸收到颗粒中，也没有被抑制的组胺释放中。这些结果显示了这些抑制剂在颗粒中的吸收，在哪些细胞是本地化的，是这些抑制剂抑制组胺释放的必要条件。关于通过细胞激活蛋白激酶C的机制和激活蛋白激酶C的蛋白磷酸化的研究现在正在进行中。

Two types of serine proteases, such as chymase and tryptase, are localized in the grnules of mast cells. We found that antibody of chymase, substrate analogues and specific inhibitor of chymase inhibited histamine release from rat mast cells but that inhibitors of tryptase did not. In addition specific inhibitors of chymase and anti-chymase F(ab')_2 also inhibited protein phosphorylation by protein kinase C after bridging of IgE-receptor. From these results, We speculate that chumase activates protein kinse C on the process of degranulation. After degranulation, chymase retained on the surface of mast cells. In order to clarify which of the chymase in the granules or on the cell surface is involved in histamine release, we examined the intra-cellular localization of the inhibitores of both histamine release and chymase, such as antichymase f(ab')_2 and ^<125>I-Bowman Burk soybean inhibitor. After incubation of these inhibitors with mast cells at 37゜C, they first bound to plasma membrane of mast cells and then were incorporated into the granules time-dependently, resulting in the inhibition of histamine release after bridging of IgE receptor. When these inhibitors were incubated with mast cells at 4゜C, they bound to plasma membrane but did not incorporated into the granules and did not also inhibit histamine release. These results show that incorporation of these inhibitors into the granules, in which chymase is localized, is essential for inhibition of histamine release by these inhibitors.Studies on the mechanisms of activation of protein kinase C by chymase and of protein phosphorylation by the activated protein kinase C are now in progress.