Localization and structures of plasma membrane estrogen receptor

1.质膜雌激素受体（M-ER）的定位用抗ER α抗体，采用包埋后定位法，对雌激素刺激后的小鼠子宫和MCF-7人乳腺癌细胞中的M-ER进行定位。雌激素刺激后，子宫内膜上皮细胞和MCF-7细胞染色质上均检测到ERα免疫反应，未见ERα核内移位。在MCF-7细胞中，反应也存在于细胞质和质膜上，尽管在细胞核、细胞质和质膜中的标记密度在每个细胞中不同，表明细胞周期异质性。刺激后15 min，细胞膜上ERα的标记密度增加。定量研究正在进行中. Western blotting检测雌激素刺激后MCF-7细胞中ER α的表达。刺激后0 ~ 60 min，ERα的表达模式在浓度和分子量方面无显著差异：65和37 kD多肽在所有样品中均与ERα抗体反应. MAPK的表达在雌激素刺激后，用蛋白质印迹法检测MAPK/ERK的表达。ERK 1，2在0 ~ 60 min内浓度基本不变，而磷酸化ERK 1，2在15和30 min时浓度升高。

1. Localization of plasma membrane estrogen receptor (M-ER)By using post-embedding method, M-ER was localized with anti-ERα antibodies in the mouse uterus and MCF-7 human breast cancer cells after estrogen stimulation. ERα immunoreaction was detected on the chromatin in the uterine epithelial cells and MCF-7 cells and intranuclear translocation of ERα was not observed after estrogen stimulation. In MCF-7 cells, reaction was also present in the cytoplasm and on the plasma membrane, although the labeling density in the nucleus, cytoplasm and plasma membrane was different in each cell, suggesting heterogeneous cell cycles. Labeling density of ERα on the cell membrane appeared to increase at 15 min after the stimulation. Quantitative study is being carried out now.2. Analysis of ERα by western blotting.After estrogen stimulation, ERα in MCF-7 cells was analyzed. There were no significant difference in ERα expression patterns concerning concentrations and molecular weights from 0 to 60 min after stimulation : 65 and 37 kD polypeptides reacted with ERα antibodies in all samples.3. Expression of MAPKAfter estrogen stimulation, MAPK/ERK expression was examined by the western blotting. Concentration of ERK 1,2 was almost constant from 0 to 60 min, but that of phosphorylated ERK 1,2 increased at 15 and 30 min after the stimulation.