Mechanisms of membrane protein trafficking and AKT/mTOR signaling that promote myelin sheath stability and growth

项目摘要 髓鞘是通过轴突粘附和膜生物发生的动态过程建立的， 形成致密的多层结构。有趣的是，只有一小部分鞘在开始时开始形成， 髓鞘形成将稳定并成熟以形成致密的髓鞘。我们知道轴突粘附蛋白是 对于确定鞘稳定性是重要的。然而，在我们对如何实现这一目标的理解上存在着根本性的差距。 这些分子在髓鞘的动态过程中维持在髓鞘/轴膜界面 包装。此外，AKT/mTOR信号传导是细胞膜生物合成的重要驱动因素， 少突胶质细胞然而，我们不知道AKT/mTOR信号转导是否驱动鞘化事件， 相反，该途径作用于轴突粘附的下游。因此，我们的目标是调查 运输髓磷脂/轴突粘附分子和激活AKT/mTOR信号传导的机制 促进鞘的稳定和生长。在aim 1中，我们将使用体内遗传操作的组合， 活细胞成像和生物化学，以研究膜运输的机制，定位MAG， 轴膜界面。在目标2中，我们将使用MAG敲除的鱼线来执行遗传上位性 实验以确定AKT/mTOR通路是否促进轴突下游的鞘稳定化， 粘连这个项目将阐明AKT/mTOR信号如何与膜蛋白相互作用 运输途径来构建髓鞘。

Project Summary Myelin sheaths are built through a dynamic process of axonal adhesion and membrane biogenesis to form a compact, multilamellar structure. Interestingly, only a fraction of sheaths that initiate at the onset of myelination will stabilize and mature to form compact myelin. We know that axonal adhesion proteins are important for determining sheath stability. However, there is a fundamental gap in our understanding of how these molecules are maintained at the myelin/axolemma interface during the dynamic process of myelin wrapping. Additionally, AKT/mTOR signaling is an important driver of membrane biogenesis in oligodendrocytes. However, we do not know whether AKT/mTOR signaling drives ensheathment events or rather this pathway acts downstream of axonal adhesion. Therefore, our objective here is to investigate the mechanisms for trafficking myelin/axonal adhesion molecules and for activating AKT/mTOR signaling to promote sheath stabilization and growth. In aim 1, we will use a combination of genetic manipulations, in vivo live-cell imaging, and biochemistry to investigate the mechanisms of membrane trafficking that localize MAG to the axolemma interface. In aim 2 we will use a MAG knockout fish line to perform genetic epistasis experiments to determine if the AKT/mTOR pathway promotes sheath stabilization downstream of axonal adhesion. Together this project will elucidate how AKT/mTOR signaling interfaces with membrane protein trafficking pathways to build a myelin sheath.