Roles of the GPI-anchored proteins PrP and Thy-1 in axon growth and regeneration

与哺乳动物不同，鱼类视神经损伤后，视网膜神经节细胞（RGC）轴突能成功再生。最近自己的证据表明，鱼类RGCs上调生长相关分子的能力，如微结构域形成reggie蛋白，与成功再生有因果关系。我们最近的研究结果表明，GPI锚定的朊病毒蛋白，鱼PrP-1和PrP-2（哺乳动物中的PrPc），以及Thy-1也代表生长相关蛋白。有趣的是，PrP和Thy-1共簇在reggie微结构域中，并与相关的信号转导分子通讯，调节Rho-GTP酶和肌动蛋白动力学。在这一建议中，1.）PrP和Thy-1对体内轴突再生和体外单细胞中轴突发生和突起形成的贡献将使用吗啉代和siRNA介导的敲低和蛋白质过表达来分析。2.）的情况。此外，将确定与PrP和Thy-1通信的信号分子-通过它们与reggies的关联-以及它们如何调节Rho-GTP酶和肌动蛋白动力学，和3）。它们是否以及如何促进特定膜蛋白的募集、突起延伸和轴突生长。这项工作旨在阐明轴突再生的分子机制，并提供新的见解PrP和Thy-1的功能，这是众所周知的，但他们的作用仍然难以捉摸。

In contrast to mammals, retinal ganglion cell (RGC) axons in fish regenerate successfully after optic nerve lesion. Recent own evidence suggests that the ability of fish RGCs to upregulate growth-associated molecules, such as the microdomain-forming reggie proteins, is causally linked to successful regeneration. Our recent results show that the GPI-anchored prion proteins, fish PrP-1 and PrP-2 (PrPc in mammals), as well as Thy-1 also represent growth-associated proteins. Interestingly, PrP and Thy-1 cocluster in reggie microdomains and communicate with associated signal transduction molecules and regulate Rho-GTPases and actin dynamics. In this proposal, 1.) the contribution of PrP and Thy-1 to axon regeneration in vivo and to axogenesis and process formation in single cells in vitro will be analysed using morpholino and siRNA-mediated knockdown and protein overexpression. 2.) Furthermore, signalling molecules which communicate with PrP and Thy-1 – through their association with the reggies - and how they regulate Rho-GTPases and actin dynamics will be determined, and 3.) whether and how they promote the recruitment of specific membrane proteins, process extension and axon growth. This work aims at elucidating molecular mechanisms underlying axon regeneration and at providing new insights into the function(s) of PrP and Thy-1 which are well known but their role has remained elusive.