Marsigliante S, Biscozzo L, Barker S, Leo G, Puddefoot J R, Vinson G P, Storelli C
Dipartimento Biologia, Università di Lecce, Italy.
J Steroid Biochem Mol Biol. 1992 Aug;42(7):777-81. doi: 10.1016/0960-0760(92)90118-3.
Using high resolution isoelectric focusing we have been able to identify a low affinity/high capacity oestrogen binding protein, which exhibits an apparent pI of 7.0. Using this system it can be separated from the previously described high affinity oestrogen receptor (ER) isoforms which focus at pI 6.1, 6.3, 6.6 and 6.8. The pI 7.0 protein was detected in 30/30 breast tumours analysed and had the binding characteristics of the cytoplasmic Type II ER (Kd = 88 +/- 8 nM). The concentration of this protein was shown to be significantly correlated with the concentration of the pI 6.6 species, which represents the major 4S isoform. It is not related to any other isoform of ER, and is expressed independently of the progesterone receptor. The importance of this observed relationship with respect to ER function remains obscure, but it may provide new insights into the role of the Type II oestrogen binding site in breast cancer.
利用高分辨率等电聚焦技术，我们得以鉴定出一种低亲和力/高容量的雌激素结合蛋白，其表观等电点为7.0。使用该系统，它能够与先前描述的聚焦于等电点6.1、6.3、6.6和6.8的高亲和力雌激素受体（ER）亚型分离。在所分析的30个乳腺肿瘤中均检测到了等电点为7.0的蛋白，其具有细胞质II型ER的结合特性（解离常数Kd = 88±8 nM）。结果显示，该蛋白的浓度与代表主要4S亚型的等电点6.6物种的浓度显著相关。它与ER的任何其他亚型均无关，且独立于孕激素受体表达。这种观察到的关系对于ER功能的重要性仍不清楚，但它可能为II型雌激素结合位点在乳腺癌中的作用提供新的见解。
