PMA induces GCMa phosphorylation and alters its stability via the PKC- and ERK-dependent pathway.
PMA induces GCMa phosphorylation and alters its stability via the PKC- and ERK-dependent pathway.
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DOI：
10.1016/j.bbrc.2011.12.059
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发表时间：
2012-01
影响因子：
3.1
通讯作者：
Y. Yasui;Kazuyo Yamada;Satoru Takahashi;M. Sugiura-Ogasawara;Katsuya Sato;D. Miyazawa;T. Sugiyama
中科院分区：
文献类型：
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作者：
Y. Yasui;Kazuyo Yamada;Satoru Takahashi;M. Sugiura-Ogasawara;Katsuya Sato;D. Miyazawa;T. Sugiyama
缺少 (GCMa) 转录因子的神经胶质细胞通过调节胎盘中负责合体滋养层正确形成的几个基因的表达，在胎盘发育中发挥着关键作用。众所周知，GCMa 的功能在转录和翻译后水平上受到环 AMP (cAMP)/蛋白激酶 A (PKA) 依赖性途径的调节，该途径的激活会增加 GCMa 蛋白水平并导致滋养层分化为合体滋养层。然而，人们对 PKC 依赖性信号传导机制对 GCMa 的调节控制知之甚少。为了研究 GCMa 是否受 PKC 依赖性途径调节，我们用佛波醇 12-肉豆蔻酸酯 13-乙酸酯 (PMA) 处理人绒毛膜癌 JEG-3 细胞，并使用我们制备的单克隆抗 GCMa 抗体研究其对 GCMa 蛋白的影响。 PMA 导致 JEG-3 细胞中内源 GCMa 蛋白水平短暂下降，同时伴随着 GCMa 磷酸化的增加。通过蛋白激酶 C (PKC) 抑制剂和丝裂原激活蛋白激酶 (MAPK) 激酶 (MEK) 抑制剂预处理，PMA 处理后的 GCMa 磷酸化和降解可有效减少，表明存在 PKC 和 MEK 依赖性机制。此外，我们鉴定出丝氨酸残基328、378和383是GCMa上的磷酸化位点，其参与PMA诱导的GCMa降解。我们的数据首次证明 GCMa 通过 PKC 和 MEK/细胞外信号调节激酶 (ERK) 依赖性机制被磷酸化，并且这种磷酸化参与其降解过程。
The glial cells missing a (GCMa) transcription factor plays a pivotal role in the placental development by regulating the expression of several genes in the placenta that are responsible for the proper formation of the syncytiotrophoblast. It is well known that the function of GCMa is regulated at both transcriptional and post-translational levels by the cyclic AMP (cAMP)/protein kinase A (PKA)-dependent pathway, the activation of which increases the GCMa protein level and leads to trophoblast differentiation into the syncytiotrophoblast. However, little is known about the regulatory control of GCMa by PKC-dependent signaling mechanism(s). To investigate whether GCMa is regulated by PKC-dependent pathway, we treated the human choriocarcinoma JEG-3 cells with phorbol 12-myristate 13-acetate (PMA) and studied its effect on the GCMa protein using a monoclonal anti-GCMa antibody we prepared. PMA caused a transient decrease in the endogenous GCMa protein level in JEG-3 cells that was accompanied by an increase in GCMa phosphorylation. The phosphorylation and degradation of GCMa by PMA treatment was effectively reduced by pretreatment with protein kinase C (PKC) inhibitors and a mitogen-activated protein kinase (MAPK) kinase (MEK) inhibitor, indicating a PKC- and MEK-dependent mechanism. Furthermore, we identified the serine residues 328, 378 and 383 to be the phosphorylation sites on GCMa that are involved in the PMA-induced degradation of GCMa. Our data demonstrate for the first time that GCMa is phosphorylated by the PKC- and MEK/extracellular signal-regulated kinase (ERK)-dependent mechanism, and that this phosphorylation is involved in its degradation process.