Moudgil V K, John J K
Biochem J. 1980 Sep 15;190(3):799-808. doi: 10.1042/bj1900799.
The glucocorticoid--receptor complex from freshly prepared rat liver cytosol is in a non-activated form, with very little affinity to bind to isolated nuclei. When such preparations were incubated with 5--10 mM-ATP at 4 degrees C, the receptor complex acquired the properties of an 'activated' transformed form, which readily bound to nuclei, ATP--Sepharose, phosphocellulose and DNA--cellulose. This transformation was comparable with the activation achieved by warming the steroid--receptor complex at 23 degrees C. The effect of ATP was specific, as it was more effective than ADP, whereas AMP had no such effect on activation. The process of receptor activation was sensitive to the presence of 10 mM-sodium molybdate; the latter blocked activation by both ATP and heat. Bivalent cations had no observable effect on the receptor activation at low temperature, but they decreased the extent of activation by ATP. The steroid-binding properties of glucocorticoid receptor remained intact under the above conditions. However, a significant increase in steroid binding occurred when ATP was preincubated with cytosol receptor before the addition of [3H]triamcinolone acetonide. ATP also stabilized the glucocorticoid--receptor complexes at 23 degrees C. These results suggest a role for ATP in receptor function and offer a convenient method of studying the activation process of glucocorticoid receptor under mild assay conditions.
从新鲜制备的大鼠肝脏细胞质中提取的糖皮质激素 - 受体复合物处于非活化形式，与分离的细胞核结合的亲和力非常低。当将此类制剂在4℃下与5 - 10 mM的ATP一起孵育时，受体复合物获得了“活化”转化形式的特性，这种形式易于与细胞核、ATP - 琼脂糖、磷酸纤维素和DNA - 纤维素结合。这种转化与在23℃下加热类固醇 - 受体复合物所实现的活化相当。ATP的作用是特异性的，因为它比ADP更有效，而AMP对活化没有这种作用。受体活化过程对10 mM钼酸钠的存在敏感；后者会阻断ATP和热引起的活化。二价阳离子在低温下对受体活化没有明显影响，但它们会降低ATP引起的活化程度。在上述条件下，糖皮质激素受体的类固醇结合特性保持完整。然而，在加入[3H]曲安奈德之前，若ATP先与细胞质受体预孵育，则类固醇结合会显著增加。ATP还能在23℃下稳定糖皮质激素 - 受体复合物。这些结果表明ATP在受体功能中发挥作用，并提供了一种在温和的检测条件下研究糖皮质激素受体活化过程的便捷方法。
