Mechanisms of Cross-talk Between EphrinB and Alternate Signaling Pathways

在正常发育过程中，许多组织的祖细胞经历进行性的 限制多能性、上皮-间充质转化、增殖、迁移 和差异化。这些事件中的大多数（如果不是全部的话）涉及细胞间的修饰， 细胞-基质粘附，以及这些粘附系统的异常修饰， 与肿瘤的形成有关。受体酪氨酸激酶的Eph家族和它们的 配体肝配蛋白在多种癌症中经常过度表达，包括 乳腺癌、小细胞肺癌和胃肠癌、黑素瘤和神经母细胞瘤。使用 在非洲爪蟾胚胎系统中，我们已经证明了由细胞内的 ephrinB的结构域影响细胞-细胞粘附，并且这种活性可以通过 与活化的FGF受体相互作用。跨膜ephrinB 1蛋白是一种 一种双向信号分子，通过其胞质结构域发出信号， 细胞运动进入眼区，而成纤维细胞生长因子的激活 受体（FGFR）抑制这些运动和视网膜命运。在非洲爪蟾胚胎中，埃甫蛋白B 在视网膜前体细胞通过与视网膜前体细胞的相互作用进入眼区中的作用。 支架蛋白Dishevelled（Dsh）。我们最近发现了Drg 1（发育调节GTP 结合蛋白1）作为Dishevelled（Dvl）的新的但必需的相互作用物和调节物， 正常纤毛发生Dvl是一个中心支架，介导规范和非规范 Wnt信号传导，可以决定性地协调各种发育和细胞过程。一 纤毛发生是这些过程中的一个，而Dvl是已知的顶端对接的关键 纤毛上皮细胞的基底体平面极化， 自从这一最初的发现以来，人们已经对参与者及其角色有了深入的了解。我们 先前报道了Drg 1的鉴定，Drg 1是一种很少研究的GTP结合蛋白1， 与Dvl相互作用并将其定位于基底体区域， Drg 1/Dv 1相互作用在纤毛发生中起关键作用的证据。我们现在表明， ccdc 108是一种与男性不育相关的蛋白质，在生殖系统中具有进化上保守的要求。 能动的多纤维丛。使用非洲爪蟾胚胎，Ccdc 108被证明是需要的， 表皮多纤毛细胞中基体向顶膜的迁移和对接 （MCC）。我们证明了Ccdc 108与IFTB复合物相互作用，并控制着IFTB的表达。 IFT的中心粒募集，而IFT允许Ccdc 108靶向纤毛。 此外，Ccdc 108是中心粒募集Drg 1和活化RhoA所必需的， 有助于在MCCs中建立顶端肌动蛋白网络的因素。最后，我们证明了CEP 97， 作为初级纤毛形成的负调节剂，与双 特异性酪氨酸磷酸化调节激酶1A（Dyrk 1a）调节 多纤毛发生我们发现，Dyrk 1a磷酸化CEP 97，这反过来又促进了 Polo样激酶1（Plk 1）的募集，Plk 1是MCC成熟的关键调节因子， 与酶Separase合作，增强中心粒脱离。因此，我们的 研究表明，Dyrk 1a和CEP 97与Plk 1协调，促进分离酶功能， 在脊椎动物MCC中正确形成多纤毛。我们对CEP 97合作作用的研究结果 和Dyrk 1a的多基因整合可能会增加我们对三体患者的现有知识 21和治疗方法的呼吸系统疾病患者的纤毛和 唐氏综合症。

During normal development progenitor cells of many tissues undergo progressive restriction of pluripotency, epithelial-to- mesenchymal transition, proliferation, migration, and differentiation. Most, if not all, of these events involve modifications of cell-cell and cell-matrix adhesion, and abnormal modifications of these adhesion systems are often associated with the formation of tumors. The Eph family of receptor tyrosine kinases and their ligands, the ephrins, are frequently over-expressed in a wide variety of cancers, including breast, small-cell lung and gastrointestinal cancers, melanomas, and neuroblastomas. Using the Xenopus embryonic system, we have demonstrated that signaling mediated by the intracellular domain of ephrinB affects cell-cell adhesion, and that this activity can be modulated by interaction with an activated FGF receptor. The transmembrane ephrinB1 protein is a bi-directional signaling molecule that signals through its cytoplasmic domain to promote cellular movements into the eye field, whereas activation of the fibroblast growth factor receptor (FGFR) represses these movements and retinal fate. In Xenopus embryos, ephrinB plays a role in retinal progenitor cell movement into the eye field through an interaction with the scaffold protein Dishevelled (Dsh). We recently identified Drg1 (Developmentally regulated GTP binding protein 1) as a new but requisite interactor and regulator of Dishevelled (Dvl) for proper ciliogenesis. Dvl is a central scaffold that mediates both canonical and non-canonical Wnt signaling and can decisively orchestrate various developmental and cellular processes. One of these processes is ciliogenesis, and while Dvl is known to be critical for apical docking and planar polarization of basal bodies in ciliated epithelial cells, little mechanistic insight into the players and their roles have been gleaned since this original discovery. We previously reported the identification of Drg1, a little studied GTP-binding protein 1, that interacts with Dvl and localizes it to the basal body region and we provided critical in vivo evidence that a Drg1/Dvl interaction plays a critical role in ciliogenesis. We now show that Ccdc108, a protein linked to male infertility, has an evolutionarily conserved requirement in motile multiciliation. Using Xenopus laevis embryos, Ccdc108 is shown to be required for the migration and docking of basal bodies to the apical membrane in epidermal multiciliated cells (MCCs). We demonstrate that Ccdc108 interacts with the IFTB complex, and governs the centriolar recruitment of IFT while IFT licenses the targeting of Ccdc108 to the cilium. Moreover, Ccdc108 is required for the centriolar recruitment of Drg1 and activated RhoA, factors that help establish the apical actin network in MCCs. Finally, we show that CEP97, which is known as a negative regulator of primary cilia formation, interacts with dual specificity tyrosine phosphorylation regulated kinase 1A (Dyrk1a) to modulate multiciliogenesis. We show that Dyrk1a phosphorylates CEP97, which in turn promotes the recruitment of Polo-like kinase 1 (Plk1), which is a critical regulator of MCC maturation that functions to enhance centriole disengagement in cooperation with the enzyme Separase.Thus, our study reveals that Dyrk1a and CEP97 coordinate with Plk1 to promote Separase function to properly form multicilia in vertebrate MCCs. Our findings on the collaborative role of CEP97 and Dyrk1a in multiciliation may add to our existing knowledge regarding patients with trisomy 21 and therapeutic approaches for the respiratory diseases in patients with ciliopathy and Down syndrome.