Cloning and characterization of human prostate coactivator ARA54, a novel protein that associates with the androgen receptor
Cloning and characterization of human prostate coactivator ARA54, a novel protein that associates with the androgen receptor
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DOI：
10.1074/jbc.274.13.8570
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发表时间：
1999-03-26
影响因子：
4.8
通讯作者：
Chang, CS
中科院分区：
文献类型：
--
作者：
Kang, HY;Yeh, SY;Chang, CS
雄激素受体 (AR) 是类固醇受体超家族的成员，可能需要共激活剂才能实现适当或最大的反式激活。通过酵母双杂交筛选和哺乳动物细胞分析，我们鉴定了一种新型配体依赖性 AR 相关蛋白 ARA54，它由 474 个氨基酸组成，分子量为 54 kDa。我们证明，ARA54 可能作为人前列腺癌 DU145 细胞中 AR 介导的反式激活的优先共激活剂。有趣的是，我们的数据还表明，在 10 nM 17 β-雌二醇或 1 mu M 羟基氟他胺存在的情况下，ARA54 可以显着增强 LNCaP 突变体 AR (ARt877a) 的转录活性，但不能增强野生型 AR 或另一种突变体 AR (ARe708k)。这些结果意味着 ARA54 和 AR 突变的位置（877 与 708）可能有助于 AR 介导的反式激活的特异性。我们的研究结果进一步表明，ARA54 的 C 端结构域可以作为显性失活抑制剂，外源全长 ARA54 可以逆转这种对 AR 转录活性的抑制作用。 ARA54 与其他 AR 共激活因子（例如 ARA70 或 SRC-1）的共表达显示出对 AR 介导的反式激活的附加刺激，这表明这些辅助因子可能单独作为 AR 共激活因子发挥作用，诱导 AR 靶基因表达。通过我们的研究结果，我们鉴定并鉴定了一种新型 AR 共激活剂 ARA54，它可能在人类前列腺的 AR 信号通路中发挥重要作用。
Androgen receptor (AR) is a member of the steroid receptor superfamily that may require coactivators for proper or maximal transactivation. Using a yeast two-hybrid screening followed by mammalian cell analyses, we identified a novel ligand-dependent AR-associated protein, ARA54, which Consists of 474 amino acids with a molecular mass of 54 kDa. We demonstrated that ARA54 might function as a preferential coactivator for AR-mediated transactivation in human prostate cancer DU145 cells. Interestingly, our data also showed that ARA54 could significantly enhance the transcriptional activity of LNCaP mutant AR (ARt877a) but not wild type AR or another mutant AR (ARe708k) in the presence of 10 nM 17 beta-estradiol or 1 mu M hydroxyflutamide. These results imply that both ARA54 and the positions of the AR mutation (877 versus 708) might contribute to the specificity of AR-mediated transactivation. Our findings further demonstrated that the C-terminal domain of ARA54 can serve as a dominant negative inhibitor and exogenous full-length ARA54 can reverse this squelching effect on AR transcriptional activity. Co-expression of ARA54 with other AR coactivators, such as ARA70 or SRC-1, showed additive stimulation of AR-mediated transactivation, which indicates that these cofactors may function individually as AR coactivators to induce AR target gene expression. Through our findings, we have identified and characterized a novel AR coactivator, ARA54, which may play an important role in the AR signaling pathway in human prostate.