Analysis of lipid-based signal transduction

已知肌醇磷脂PI(4，5)P_2具有信号转导、内吞作用、细胞骨架调节等多种细胞功能，其池主要定位于细胞膜。在本研究中，我们用冷冻断裂复制品标记法显示，当细胞受到血管紧张素II或钙离子载体刺激时，质膜、小凹、包被小凹的各个区域质膜PI(4，5)P_2水平降低的时间进程是不同的。这些结果表明，PI(4，5)P2在质膜上被区域化，从而改变了有限区域内PI(4，5)P2的水平。

It has been known that inositolphospholipid PI(4,5)P_2, whose pool is mainly localized in the plasma membrane, has some cellular functions, such as signal transduction, endocytosis, cytoskeleton regulation and so on. In this study, we show that, using freeze-fracture replica labeling method, the time course of reduction in the PI(4,5)P_2 level in the plasma membrane is different in each area of the undifferential plasma membrane, caveola, coated pit when cells are stimulated with angiotensin II or Ca^<2+> ionophore. These results indicate that PI(4,5)P_2 is compartmentalized in the plasma membrane, resulting in changing the level of PI(4,5)P_2 in the limited area.