Mathavan Ketan, Khedgikar Vikram, Bartolo Vanessa, Alfandari Dominique
Department of Veterinary and Animal Sciences, University of Massachusetts Amherst, Amherst, Massachusetts, United States of America.
PLoS One. 2017 Nov 30;12(11):e0188963. doi: 10.1371/journal.pone.0188963. eCollection 2017.
During development, a multi-potent group of cells known as the cranial neural crest (CNC) migrate to form craniofacial structures. Proper migration of these cells requires proteolysis of cell adhesion molecules, such as cadherins. In Xenopus laevis, preventing extracellular cleavage of cadherin-11 impairs CNC migration. However, overexpression of the soluble cleavage product (EC1-3) is capable of rescuing this phenotype. The mechanism by which EC1-3 promotes CNC migration has not been investigated until now. Here we show that EC1-3 stimulates phosphorylation of Akt, a target of PI3K, in X.laevis CNC. Through immunoprecipitation experiments, we determined that EC1-3 interacts with all ErbB receptors, PDGFRα, and FGFR1. Of these receptors, only ErbB2 was able to produce an increase in Akt phosphorylation upon treatment with a recombinant EC1-3. This increase was abrogated by mubritinib, an inhibitor of ErbB2. We were able to recapitulate this decrease in Akt phosphorylation in vivo by knocking down ErbB2 in CNC cells. Knockdown of the receptor also significantly reduced CNC migration in vivo. We confirmed the importance of ErbB2 and ErbB receptor signaling in CNC migration using mubritinib and canertinib, respectively. Mubritinib and the PI3K inhibitor LY294002 significantly decreased cell migration while canertinib nearly prevented it altogether. These data show that ErbB2 and Akt are important for CNC migration and implicate other ErbB receptors and Akt-independent signaling pathways. Our findings provide the first example of a functional interaction between the extracellular domain of a type II classical cadherin and growth factor receptors.
在发育过程中，一群被称为颅神经嵴（CNC）的多能细胞迁移形成颅面结构。这些细胞的正常迁移需要细胞粘附分子（如钙粘蛋白）的蛋白水解。在非洲爪蟾中，阻止钙粘蛋白-11的细胞外裂解会损害CNC迁移。然而，可溶性裂解产物（EC1-3）的过表达能够挽救这种表型。直到现在，EC1-3促进CNC迁移的机制尚未得到研究。在这里，我们表明EC1-3刺激非洲爪蟾CNC中PI3K的靶标Akt的磷酸化。通过免疫沉淀实验，我们确定EC1-3与所有ErbB受体、PDGFRα和FGFR1相互作用。在这些受体中，只有ErbB2在用重组EC1-3处理后能够使Akt磷酸化增加。这种增加被ErbB2抑制剂mubritinib消除。我们能够通过在CNC细胞中敲低ErbB2在体内重现Akt磷酸化的这种降低。受体的敲低也显著降低了体内CNC的迁移。我们分别使用mubritinib和卡奈替尼证实了ErbB2和ErbB受体信号在CNC迁移中的重要性。mubritinib和PI3K抑制剂LY294002显著降低细胞迁移，而卡奈替尼几乎完全阻止了细胞迁移。这些数据表明ErbB2和Akt对CNC迁移很重要，并暗示了其他ErbB受体和Akt非依赖性信号通路。我们的发现提供了II型经典钙粘蛋白细胞外结构域与生长因子受体之间功能相互作用的第一个例子。
