cAMP Enhances Estrogen-Related Receptor α (ERRα) Transcriptional Activity at the SP-A Promoter by Increasing Its Interaction with Protein Kinase A and Steroid Receptor Coactivator 2 (SRC-2)
cAMP Enhances Estrogen-Related Receptor α (ERRα) Transcriptional Activity at the SP-A Promoter by Increasing Its Interaction with Protein Kinase A and Steroid Receptor Coactivator 2 (SRC-2)
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DOI：
10.1210/me.2008-0282
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发表时间：
2009-06-01
影响因子：
--
通讯作者：
Mendelson, Carole R.
中科院分区：
文献类型：
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作者：
Liu, Dongyuan;Benlhabib, Houda;Mendelson, Carole R.
雌激素相关受体（ERR α）通过直接结合其5 '-侧翼区域内的ERR应答元件（埃雷，5'-TGACCTTA-3 '），在肺II型细胞中人表面活性蛋白-A（SP-A）基因的基础和cAMP诱导表达中起关键作用。此外，蛋白激酶A（PKA）上调hSP-A启动子的ERR α活化。在本研究中，使用培养的人胎肺II型细胞，我们观察到cAMP增强ERR α磷酸化和核表达水平。cAMP/PKA刺激SP-A启动子的ERR α活化被PKA抑制剂H89阻断，而MAPK P38抑制剂SB 203580和MAPK激酶抑制剂PD 98059具有可忽略的至中等的作用。这表明cAMP通过PKA选择性地作用以增加ERR α转录活性。在测试的几种共激活因子中，类固醇受体共激活因子2（SRC-2）对增加SP-A启动子处的ERR α转录活性具有最显著的作用;这通过与PKA催化亚基（PKAcat）共转染而增强。有趣的是，SRC-2，ERR α，和PKAcat在II型细胞核提取物的相互作用在埃雷，这是增强cAMP和抑制H89。cAMP增加PKAcat和SRC-2与肺II型细胞中埃雷基因组区域的体内结合。在诱变研究中，发现三种丝氨酸（S87、S114和S277）对PKA和SRC-2诱导ERR α转录活性至关重要。总的来说，这些发现表明cAMP/PKA信号传导增强ERR α磷酸化和核定位，募集到SP-A启动子，以及与PKAcat和SRC-2的相互作用，导致SP-A基因转录的上调。（分子内分泌学23：772-783，2009）
Estrogen-related receptor (ERR alpha) plays a critical role in basal and cAMP-induced expression of the human surfactant protein-A (SP-A) gene in lung type II cells through direct binding to an ERR response element (ERRE, 5'-TGACCTTA-3') within its 5'-flanking region. Furthermore, protein kinase A (PKA) up-regulates ERR alpha activation of the hSP-A promoter. In the present study, using cultured human fetal lung type II cells, we observed that cAMP enhanced ERR alpha phosphorylation and nuclear expression levels. cAMP/PKA stimulation of ERR alpha activation of the SP-A promoter was blocked by the PKA inhibitor, H89, whereas the MAPK P38 inhibitor, SB203580, and the MAPK kinase inhibitor, PD98059, had negligible to modest effects. This suggests that cAMP acts selectively through PKA to increase ERR alpha transcriptional activity. Of several coactivators tested, steroid receptor coactivator 2 (SRC-2) had the most pronounced effect to increase ERR alpha transcriptional activity at the SP-A promoter; this was enhanced by cotransfection with PKA catalytic subunit (PKAcat). Interestingly, SRC-2, ERR alpha, and PKAcat in type II cell nuclear extracts interacted at the ERRE; this was enhanced by cAMP and inhibited by H89. cAMP increased in vivo binding of PKAcat and SRC-2 to the ERRE genomic region in lung type II cells. In mutagenesis studies, three serines (S87, S114, and S277) were found to be critical for PKA and SRC-2 induction of ERR alpha transcriptional activity. Collectively, these findings indicate that cAMP/PKA signaling enhances ERR alpha phosphorylation and nuclear localization, recruitment to the SP-A promoter, and interaction with PKAcat and SRC-2, resulting in the up-regulation of SP-A gene transcription. (Molecular Endocrinology 23: 772-783, 2009)