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

项目摘要 髓鞘是通过轴突黏附和膜生物发生的动态过程建立的 形成紧凑的多层结构。有趣的是，只有一小部分鞘是在 髓鞘形成会稳定和成熟，形成致密的髓鞘。我们知道轴突黏附蛋白是 对确定护套稳定性很重要。然而，我们对如何做到这一点的理解存在一个根本的差距 在髓鞘的动态过程中，这些分子被维持在髓鞘/轴膜的界面上 包装好了。此外，AKT/mTOR信号转导通路是细菌细胞膜生物发生的重要驱动因素。 少突胶质细胞。然而，我们不知道AKT/mTOR信号是驱动鞘事件还是 相反，这一途径作用于轴突粘连的下游。因此，我们在这里的目标是调查 运输髓鞘/轴突黏附分子和激活AKT/mTOR信号转导机制 促进鞘的稳定和生长。在目标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，以研究膜转运的机制，定位MAG到 轴膜界面。在目标2中，我们将使用MAG基因敲除鱼线来执行遗传上位性 确定AKT/mTOR通路是否促进轴突下游鞘稳定的实验 粘附力。该项目将阐明AKT/mTOR信号如何与膜蛋白相互作用 构建髓鞘的运输途径。

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.