Extracellular Signal-regulated Kinase (ERK)-dependent Phosphorylation of Y-Box-binding Protein 1 (YB-1) Enhances Gene Expression in Granulosa Cells in Response to Follicle-stimulating Hormone (FSH)
Extracellular Signal-regulated Kinase (ERK)-dependent Phosphorylation of Y-Box-binding Protein 1 (YB-1) Enhances Gene Expression in Granulosa Cells in Response to Follicle-stimulating Hormone (FSH)
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DOI：
10.1074/jbc.m115.705368
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发表时间：
2016-06-03
影响因子：
4.8
通讯作者：
Hunzicker-Dunn, Mary E.
中科院分区：
文献类型：
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作者：
Donaubauer, Elyse M.;Hunzicker-Dunn, Mary E.
在卵泡内，未成熟的卵母细胞被颗粒细胞（GC）包围和支持。FSH刺激GC导致其增殖和分化，这是生育所必需的事件。FSH激活多种信号通路，调节卵泡成熟所需的基因。在此，我们研究了Y-box-binding protein-1（YB-1）在GC中的作用。YB-1是调节转录和翻译的核酸结合蛋白。我们的研究结果表明，FSH在15分钟内促进Ser（102）上YB-1磷酸化的增加，并维持在显著增加的水平，直到处理后8小时。FSH刺激的YB-1（Ser（102））磷酸化通过用PKA选择性抑制剂PKA抑制剂（PKI）、MEK抑制剂PD 98059或核糖体S6激酶-2（RSK-2）抑制剂BI-D1870预处理GC来防止。因此，YB-1在Ser（102）上的磷酸化是PKA、ERK和RSK-2依赖性的。然而，在没有FSH的情况下，用蛋白磷酸酶1（PP 1）抑制剂互变霉素预处理GC增加了YB-1（Ser（102））的磷酸化; FSH没有进一步增加YB-1（Ser（102））的磷酸化。这一结果表明RSK-2的主要作用是抑制PP 1而不是直接磷酸化Ser（102）上的YB-1。YB-1与PP 1 β催化亚基和RSK-2共免疫沉淀。用去磷酸腺病毒YB-1（S102 A）突变体转导GC阻止FSH诱导Egfr、Cyp 19 a1、Inha、Lhcgr、Cyp 11 a1、Hsd 17 b1和Pappa mRNA以及雌二醇-17 β的产生。总的来说，我们的研究结果表明，YB-1通过ERK/RSK-2信号通路在Ser（102）上的磷酸化是FSH介导的卵泡成熟为排卵前表型所需的靶基因表达所必需的。
Within the ovarian follicle, immature oocytes are surrounded and supported by granulosa cells (GCs). Stimulation of GCs by FSH leads to their proliferation and differentiation, events that are necessary for fertility. FSH activates multiple signaling pathways to regulate genes necessary for follicular maturation. Herein, we investigated the role of Y-box-binding protein-1 (YB-1) within GCs. YB-1 is a nucleic acid binding protein that regulates transcription and translation. Our results show that FSH promotes an increase in the phosphorylation of YB-1 on Ser(102) within 15 min that is maintained at significantly increased levels until similar to 8 h post treatment. FSH-stimulated phosphorylation of YB-1(Ser(102)) is prevented by pretreatment of GCs with the PKA-selective inhibitor PKA inhibitor (PKI), the MEK inhibitor PD98059, or the ribosomal S6 kinase-2 (RSK-2) inhibitor BI-D1870. Thus, phosphorylation of YB-1 on Ser(102) is PKA-, ERK-, and RSK-2-dependent. However, pretreatment of GCs with the protein phosphatase 1 (PP1) inhibitor tautomycin increased phosphorylation of YB-1(Ser(102)) in the absence of FSH; FSH did not further increase YB-1(Ser(102)) phosphorylation. This result suggests that the major effect of RSK-2 is to inhibit PP1 rather than to directly phosphorylate YB-1 on Ser(102). YB-1 coimmunoprecipitated with PP1 beta catalytic subunit and RSK-2. Transduction of GCs with the dephospho-adenoviral-YB-1(S102A) mutant prevented the induction by FSH of Egfr, Cyp19a1, Inha, Lhcgr, Cyp11a1, Hsd17b1, and Pappa mRNAs and estradiol-17 beta production. Collectively, our results reveal that phosphorylation of YB-1 on Ser(102) via the ERK/RSK-2 signaling pathway is necessary for FSH-mediated expression of target genes required for maturation of follicles to a preovulatory phenotype.