Fyn‐mediated phosphorylation of Pyk2 promotes its activation and dissociation downstream of gonadotropin‐releasing hormone receptor
Fyn‐mediated phosphorylation of Pyk2 promotes its activation and dissociation downstream of gonadotropin‐releasing hormone receptor
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Fyn 介导的 Pyk2 磷酸化促进促性腺激素释放激素受体下游的激活和解离
DOI：
10.1111/febs.15231
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发表时间：
2020
期刊：
影响因子：
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通讯作者：
Yamamoto Hideyuki
中科院分区：
文献类型：
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作者：
Higa‐Nakamine Sayomi;Okitsu‐Sakurayama Shiho;Kina Shinichiro;Yamamoto Hideyuki
促性腺激素释放激素（GnRH）受体在下丘脑GnRH神经元和垂体前叶促性腺激素细胞中高度表达。在我们之前的研究中，我们发现刺激GnRH受体激活蛋白激酶D1（PKD 1），PKD 1参与了Fyn介导的培养GnRH神经元（GT 1 - 7细胞）中富含脯氨酸的酪氨酸激酶2（Pyk 2）的激活。在本研究中，我们研究了Pyk 2激活的分子机制以及Pyk 2和Fyn在GT 1 - 7细胞中的相互作用。Pyk 2定点突变体的实验表明，酪氨酸402（Tyr 402）通过自磷酸化和Fyn磷酸化，而Tyr 579主要由Fyn磷酸化。我们发现，达沙替尼，Src家族抑制剂，增强Pyk 2和Fyn的相互作用。Pyk 2和Fyn定点突变体的实验表明，达沙替尼增强了Pyk 2在Tyr 402和Fyn中Src同源2结构域处自磷酸化的结合。我们目前的数据可能表明，完全激活的Pyk 2在Tyr 402和Tyr 579以外的位点上Fyn介导的Pyk 2磷酸化后与Fyn解离。
The receptor for gonadotropin‐releasing hormone (GnRH) is highly expressed in hypothalamic GnRH neurons, as well as in anterior pituitary gonadotrophs. In our previous study, we found that stimulation of the GnRH receptor activated protein kinase D1 (PKD1), and PKD1 was involved in the Fyn‐mediated activation of proline‐rich tyrosine kinase 2 (Pyk2) in cultured GnRH neurons (GT1‐7 cells). In the present study, we examined the molecular mechanisms of Pyk2 activation and the interaction of Pyk2 and Fyn in GT1‐7 cells. Experiments with site‐directed mutants of Pyk2 indicated that tyrosine 402 (Tyr402) was phosphorylated both by autophosphorylation and by Fyn, whereas Tyr579 was phosphorylated mainly by Fyn. We found that dasatinib, a Src family inhibitor, enhanced the interaction of Pyk2 and Fyn. Experiments with site‐directed mutants of Pyk2 and Fyn indicated that dasatinib enhanced the binding of Pyk2 autophosphorylated at Tyr402 and the Src homology 2 domain in Fyn. Our present data may suggest that fully activated Pyk2 dissociates from Fyn after Fyn‐mediated phosphorylation of Pyk2 at sites other than Tyr402 and Tyr579.