Adhesion-related kinase induction of migration requires phosphatidylinositol-3-kinase and Ras stimulation of Rac activity in immortalized gonadotropin-releasing hormone neuronal cells
Adhesion-related kinase induction of migration requires phosphatidylinositol-3-kinase and Ras stimulation of Rac activity in immortalized gonadotropin-releasing hormone neuronal cells
复制标题
DOI：
10.1210/en.2007-0039
复制
发表时间：
2007-06-01
期刊：
影响因子：
4.8
通讯作者：
Wierman, Margaret E.
中科院分区：
文献类型：
--
作者：
Nielsen-Preiss, Sheila M.;Allen, Melissa P.;Wierman, Margaret E.
GnRH神经元在发育过程中迁移到下丘脑。虽然迁移缺陷可能导致生殖轴激活紊乱，导致性成熟延迟或缺失，但调节GnRH神经元迁移的具体因素在很大程度上仍然未知。受体酪氨酸激酶，粘连相关激酶（Ark）（也称为Axl， UFO和Tyro7），与GnRH神经元细胞的迁移有关。其配体，生长抑制特异性基因6 （Gas6）的结合，通过Rac和p38 MAPK促进NLT GnRH神经元细胞的细胞骨架重塑和迁移。在这里，我们研究了信号通路中靠近Rac的Axl效应器。在GnRH神经元细胞中，抑制PI3K后，Gas6/ axl诱导的板足形成和迁移被阻断。PI3K的p85亚基与Axl共免疫沉淀，并以gas6敏感的方式磷酸化。此外，GnRH神经元细胞中PI3K的抑制降低了gas6诱导的Rac激活。Ras显性阴性形式的外源性表达也减少了GnRH神经元板足的形成、迁移和Rac的激活。PI3K抑制除Rac激活和迁移外，还阻断Ras。相比之下，药理阻断磷脂酶C γ效应物、蛋白激酶C或钙/钙调蛋白激酶II，对Gas6/Axl信号传导促进Rac激活或刺激细胞骨架重组和迁移没有影响。综上所述，这些数据表明PI3K-Ras通路是Rac上游Axl作用诱导GnRH神经元细胞迁移的主要介质。
GnRH neurons migrate into the hypothalamus during development. Although migratory defects may result in disordered activation of the reproductive axis and lead to delayed or absent sexual maturation, specific factors regulating GnRH neuronal migration remain largely unknown. The receptor tyrosine kinase, adhesion-related kinase (Ark) (also known as Axl, UFO, and Tyro7), has been implicated in the migration of GnRH neuronal cells. Binding of its ligand, growth arrest-specific gene 6 (Gas6), promotes cytoskeletal remodeling and migration of NLT GnRH neuronal cells via Rac and p38 MAPK. Here, we examined the Axl effectors proximal to Rac in the signaling pathway. Gas6/Axl-induced lamellipodia formation and migration were blocked after phosphatidylinositol-3-kinase (PI3K) inhibition in GnRH neuronal cells. The p85 subunit of PI3K coimmunoprecipitated with Axl and was phosphorylated in a Gas6-sensitive manner. In addition, PI3K inhibition in GnRH neuronal cells diminished Gas6-induced Rac activation. Exogenous expression of a dominant-negative form of Ras also decreased GnRH neuronal lamellipodia formation, migration, and Rac activation. PI3K inhibition blocked Ras in addition to Rac activation and migration. In contrast, pharmacological blockade of the phospholipase C gamma effectors, protein kinase C or calcium/calmodulin protein kinase II, had no effect on Gas6/Axl signaling to promote Rac activation or stimulate cytoskeletal reorganization and migration. Together, these data show that the PI3K-Ras pathway is a major mediator of Axl actions upstream of Rac to induce GnRH neuronal cell migration.