Grossman A, Oppenheim J, Grondin G, St Jean P, Beaudoin A R
Department of Pharmacology, New York University Medical Center, New York 10016.
Endocrinology. 1989 Jun;124(6):2857-66. doi: 10.1210/endo-124-6-2857.
Significant amounts of an estradiol-binding protein (EBP) are present in pancreatic acinar cells. This protein differs from the one found in female reproductive tissues and secondary sex organs (which is commonly referred to as estrogen receptor). EBP has now been purified from rat pancreas and was used as an antigen to induce polyclonal antibodies in rabbits. The antiserum obtained was purified initially by ammonium sulfate fractionation and then still further by interaction with a protein fraction from pancreas that was devoid of estradiol-binding activity. The latter procedure was used to precipitate nonspecific immunoglobulin Gs. Western blot analysis demonstrated that the anti-EBP antibody reacted specifically with a doublet of protein bands having mol wt of 64K and 66K. When this purified antibody was used as an immunocytochemical probe in conjunction with protein-A-gold, acinar cells were labeled on the surface of the endoplasmic reticulum, on the plasma membrane, and in mitochondria. This specific labeling pattern was not observed when preimmune serum was used. No labeling was observed over the nucleus, Golgi apparatus, or zymogen granules with purified anti-EBP antibodies. The unexpected distribution of EBP in both the endoplasmic reticulum and mitochondria is discussed.
胰腺腺泡细胞中存在大量雌二醇结合蛋白（EBP）。这种蛋白质与在女性生殖组织和第二性器官中发现的蛋白质不同（后者通常被称为雌激素受体）。EBP现已从大鼠胰腺中纯化出来，并用作抗原在兔体内诱导多克隆抗体。获得的抗血清首先通过硫酸铵分级分离进行纯化，然后通过与来自胰腺的无雌二醇结合活性的蛋白质部分相互作用进一步纯化。后一程序用于沉淀非特异性免疫球蛋白Gs。蛋白质印迹分析表明，抗EBP抗体与分子量为64K和66K的双蛋白带特异性反应。当这种纯化的抗体与蛋白A-金结合用作免疫细胞化学探针时，腺泡细胞在内质网表面、质膜和线粒体中被标记。使用免疫前血清时未观察到这种特异性标记模式。用纯化的抗EBP抗体在细胞核、高尔基体或酶原颗粒上未观察到标记。本文讨论了EBP在内质网和线粒体中的意外分布。
