Glyceraldehyde-3-phosphate dehydrogenase enhances transcriptional activity of androgen receptor in prostate cancer cells
Glyceraldehyde-3-phosphate dehydrogenase enhances transcriptional activity of androgen receptor in prostate cancer cells
复制标题
DOI：
10.1074/jbc.m610724200
复制
发表时间：
2007-08-03
影响因子：
4.8
通讯作者：
Nakano, Yoshihisa
中科院分区：
文献类型：
--
作者：
Harada, Naoki;Yasunaga, Ryoko;Nakano, Yoshihisa
雄激素受体（AR）作为参与正常和癌性前列腺细胞的增殖和分化的基因的转录因子起作用。与AR结合的辅激活因子是最大雄激素作用所必需的。在这里，我们报告说，增加甘油醛-3-磷酸脱氢酶（GAPDH）的表达在前列腺癌细胞系中的低至1.8倍增强AR的转录活性（但不是糖皮质激素受体或雌激素受体α的转录活性）在配体依赖性的方式，并导致前列腺特异性抗原的表达增加。小干扰RNA介导的GAPDH敲低显著减弱配体激活的AR反式激活。免疫沉淀分析表明，存在一个内源性的蛋白质复合物含有GAPDH和AR在细胞质和细胞核。将核定位信号（NLS）添加到GAPDH（GAPDH-NLS）中完全消除GAPDH反式激活AR的能力。野生型GAPDH和GAPDH-NLS都不能增强突变型AR（AR Delta C-Nuc）的转录活性，突变型AR是细胞核中AR的组成型活性形式，即使GAPDH-NLS与野生型AR或AR Delta C-Nuc形成复合物。缺乏脱氢酶活性的突变GAPDH增强AR反式激活。GAPDH增强了AR（T875 A）的转录活性，AR（T875 A）被拮抗剂如羟基氟氯噻嗪或醋酸环丙孕酮激活。这些结果表明，GAPDH作为一种共激活剂，对AR具有高选择性，并独立于其糖酵解活性增强AR反式激活。此外，这些数据表明，在细胞质而不是细胞核中形成GAPDH中心点AR复合物对于GAPDH增强AR反式激活是必需的。
Androgen receptor (AR) functions as a transcriptional factor for genes involved in proliferation and differentiation of normal and cancerous prostate cells. Coactivators that bind to AR are required for maximal androgen action. Here we report that increasing the expression of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) in a prostate cancer cell line by as little as 1.8-fold enhances transcriptional activity of AR ( but not the transcriptional activity of glucocorticoid receptor or estrogen receptor alpha) in a ligand-dependent manner and results in an increased expression of prostate-specific antigen. Small interference RNA-mediated knockdown of GAPDH significantly attenuated ligand-activated AR transactivation. Immunoprecipitation analysis revealed the presence of an endogenous protein complex containing GAPDH and AR in both the cytoplasm and nucleus. Addition of a nuclear localization signal (NLS) to GAPDH (GAPDH-NLS) completely abolished the ability of GAPDH to transactivate AR. Neither wild-type GAPDH nor GAPDH-NLS enhanced transcriptional activity of mutant AR (AR Delta C-Nuc) that is a constitutively active form of AR in the nucleus, even though GAPDH-NLS formed a complex with wild-type AR or AR Delta C-Nuc. AR transactivation was enhanced by a mutant GAPDH lacking dehydrogenase activity. GAPDH enhanced the transcriptional activity of AR(T875A) activated by an antagonist such as hydroxyflutamide or cyproterone acetate. These results indicate that GAPDH functions as a coactivator with high selectivity for AR and enhances AR transactivation independent of its glycolytic activity. Further, these data suggest that formation of a GAPDH center dot AR complex in the cytoplasm rather than nucleus is essential for GAPDH to enhance AR transactivation.