Eisen C, Meyer C, Christ M, Theisen K, Wehling M
Medizinische Klinik, Klinikum Innenstadt, University of Munich, Federal Republic of Germany.
Cell Mol Biol (Noisy-le-grand). 1994 May;40(3):351-8.
Fast in vitro effects of aldosterone on the Na+/H(+)-exchanger, inositoltrisphosphate generation and corresponding specific binding to plasma membranes at Kd-values of approximately 0.1 nM have been found in human mononuclear leukocytes and vascular smooth muscle cells. The novel aldosterone membrane receptor was analyzed on SDS-PAGE after labeling of microsomal membranes from human mononuclear leukocytes with a [125I]-aldosterone-derivative by use of BASED as a photoactivatable crosslinker. Binding of 1 nM [125I]-aldosterone was found at a molecular weight of approximately 50 kDa which was absent with 1 microM cold aldosterone, but not cortisol in the binding media. This aldosterone-selectivity is typical and discriminatory for the new aldosterone membrane receptor. Solubilization of the receptor protein from membranes by high salt concentrations (1 M NaCl, 1 mM EDTA) was not achieved. It, thus, appears as an integral membrane protein. Dithiothreitol, a sulfhydryl agent, does not reduce specific aldosterone binding indicating the absence of SH-groups in the binding domain or sensitive structures of the receptors. The results are the first to characterize the novel membrane receptor for aldosterone with regard to molecular weight and basic properties. These findings and other related results are reviewed here.
已在人单核白细胞和血管平滑肌细胞中发现醛固酮对钠/氢交换体、肌醇三磷酸生成以及在约0.1 nM解离常数（Kd值）下与质膜的相应特异性结合具有快速的体外作用。在用[125I] -醛固酮衍生物标记人单核白细胞微粒体膜后，使用基于光活化交联剂的方法在SDS - PAGE上分析新型醛固酮膜受体。在约50 kDa的分子量处发现1 nM [125I] -醛固酮的结合，在结合介质中加入1 μM冷醛固酮时该结合消失，但加入皮质醇时不会消失。这种醛固酮选择性对于新型醛固酮膜受体来说是典型且具有鉴别性的。未通过高盐浓度（1 M NaCl，1 mM EDTA）从膜中溶解受体蛋白。因此，它似乎是一种整合膜蛋白。巯基试剂二硫苏糖醇不会降低醛固酮特异性结合，这表明在结合域或受体的敏感结构中不存在巯基。这些结果首次在分子量和基本特性方面对新型醛固酮膜受体进行了表征。此处对这些发现及其他相关结果进行了综述。
