Mechanism of action of a steroidal antiglucocorticoid in lymphoid cells.
Mechanism of action of a steroidal antiglucocorticoid in lymphoid cells.
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类固醇抗糖皮质激素在淋巴细胞中的作用机制。
DOI：
10.1016/s0021-9258(19)39871-0
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发表时间：
1990
期刊：
影响因子：
--
通讯作者：
U. Gehring
中科院分区：
文献类型：
--
作者：
B. Segnitz;U. Gehring
我们比较了从小鼠淋巴瘤细胞中提取的受体与糖皮质激素、曲安奈德或高亲和力抗糖皮质激素RU 38486 [17 β-羟基-11 β-（4-二甲氨基苯基）-17 α-（1-丙炔基）-雌甾-4，9-二烯-3-酮]复合后的生物化学性质。在盐处理后，两种类型的高分子量受体复合物产生对DNA具有相同亲和力的解离形式。升高的温度引起激动剂复合物的亚基解离，但拮抗剂复合物的配体解离。后者被阻止，如果亚基解离被阻断的钠，但不是通过化学交联的异聚体受体。免疫化学研究表明RU 38486复合物的不稳定性仅影响结合配体的水平，但不影响受体多肽的完整性。在37 ℃的完整细胞中，受体多肽仅在激素存在的情况下与细胞核结合，而在激素不存在或存在抗激素的情况下不与细胞核结合。在37 ℃下与RU 38486孵育的细胞在胞质溶胶中保留了其配体结合形式的高分子量受体。这些数据表明，在生理条件下的完整细胞中，拮抗剂与异聚体受体结合并阻断其解离成亚基，从而防止核受体易位。
We compared the biochemical properties of receptors extracted from mouse lymphoma cells and complexed with the glucocorticoid, triamcinolone acetonide, or with the high affinity antiglucocorticoid RU 38486 [17 beta-hydroxy-11 beta-(4-dimethylaminophenyl)-17 alpha-(1-propynyl)-estra- 4,9-diene-3-one]. Upon salt treatment the high molecular weight receptor complexes of both types yielded dissociated forms that had the same affinity for DNA. Increased temperature caused subunit dissociation of the agonist complex but ligand dissociation of the antagonist complex. The latter was prevented if subunit dissociation was blocked by sodium molybdate but not by chemical cross-linking of the heteromeric receptor. Immunochemical studies suggest that the instability of the RU 38486 complex only affects the level of bound ligand but not the integrity of the receptor polypeptide. In intact cells at 37 degrees C the receptor polypeptide associated with nuclei only in the presence of hormone but not in its absence or if the antihormone was present. Cells incubated at 37 degrees C with RU 38486 retained in the cytosol the high molecular weight receptor in its ligand bound form. The data suggest that in intact cells under physiological conditions the antagonist binds to the heteromeric receptor and blocks its dissociation into subunits thus preventing nuclear receptor translocation.