Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.
PLoS One. 2012;7(2):e31258. doi: 10.1371/journal.pone.0031258. Epub 2012 Feb 15.
The receptor tyrosine kinase RET plays an essential role during embryogenesis in regulating cell proliferation, differentiation, and migration. Upon glial cell line-derived neurotrophic factor (GDNF) stimulation, RET can trigger multiple intracellular signaling pathways that in concert activate various downstream effectors. Here we report that the RET receptor induces calcium (Ca(2+)) signaling and regulates neocortical neuronal progenitor migration through the Phospholipase-C gamma (PLCγ) binding domain Tyr1015. This signaling cascade releases Ca(2+) from the endoplasmic reticulum through the inositol 1,4,5-trisphosphate receptor and stimulates phosphorylation of ERK1/2 and CaMKII. A point mutation at Tyr1015 on RET or small interfering RNA gene silencing of PLCγ block the GDNF-induced signaling cascade. Delivery of the RET mutation to neuronal progenitors in the embryonic ventricular zone using in utero electroporation reveal that Tyr1015 is necessary for GDNF-stimulated migration of neurons to the cortical plate. These findings demonstrate a novel RET mediated signaling pathway that elevates cytosolic Ca(2+) and modulates neuronal migration in the developing neocortex through the PLCγ binding domain Tyr1015.
受体酪氨酸激酶 RET 在胚胎发生过程中对于调节细胞增殖、分化和迁移起着至关重要的作用。在胶质细胞系衍生的神经营养因子（GDNF）刺激下，RET 可以触发多种细胞内信号通路，这些通路协同激活各种下游效应物。在这里，我们报告 RET 受体通过磷酸脂酶 C 伽马（PLCγ）结合域 Tyr1015 诱导钙（Ca(2+)）信号并调节新皮质神经元祖细胞的迁移。这个信号级联反应通过三磷酸肌醇受体从内质网中释放 Ca(2+)，并刺激 ERK1/2 和 CaMKII 的磷酸化。RET 上 Tyr1015 点突变或 PLCγ 的小干扰 RNA 基因沉默会阻断 GDNF 诱导的信号级联反应。使用胚胎室电穿孔将 RET 突变体递送到胚胎室区的神经元祖细胞中，结果表明 Tyr1015 对于 GDNF 刺激的神经元向皮质板的迁移是必需的。这些发现表明，通过 PLCγ 结合域 Tyr1015，RET 介导的信号通路可以提高细胞浆中的 Ca(2+)浓度，并调节发育中的新皮质中的神经元迁移。
