Neuroglial interactions at the node of Ranvier

描述（由申请人提供）：有髓鞘轴突中的离子通道簇对于正常的神经系统功能至关重要。离子通道通过神经元-胶质细胞相互作用聚集在Ranvier节点。然而，负责通道集群的机制仍然知之甚少。最近的研究表明，多种机制可能有助于节点的形成。其中，由锚蛋白和血影蛋白组成的轴突膜下细胞骨架被认为是关键成分。特别是，节点的Ranvier本身是丰富的与anke-G（ankG）和？IV血影蛋白; ankG被认为是直接结合到Na+和K+通道，然后连接到肌动蛋白细胞骨架通过？IV血影蛋白。在帕拉诺迪斯，无论是踝关节B和？II血影蛋白聚集在一起，尽管它们在副阳极的功能仍然未知。Paranodes也被认为是作为一个paranodal扩散屏障和第二种机制，以介导离子通道聚集在节点，虽然负责这种屏障功能的机制仍然未知。此外，阐明副阳极功能的一个主要障碍是在该位点鉴定的蛋白质相对较少。在这个建议中，我们将寻求确定节点和paranodal细胞骨架的功能节点的郎维组装和维护。我们将使用三种新的小鼠模型，利用Cre-Lox技术来控制时间和空间（细胞类型特异性）表达的ankG，ankB，和？II血影蛋白。我们将沉默这些蛋白质的表达在外周感觉神经元，视网膜神经节细胞，并在髓鞘神经胶质细胞在发展和成人。最后，我们将使用蛋白质组学的方法来识别新的paranodal蛋白，然后试图确定它们的功能。

DESCRIPTION (provided by applicant): Ion channel clustering in myelinated axons is essential for proper nervous system function. Ion channels are clustered at nodes of Ranvier through neuron-glia interactions. However, the mechanisms responsible for channel clustering remain poorly understood. Recent studies suggest that multiple mechanisms may contribute to node formation. Among these, the axonal submembranous cytoskeleton comprised of ankyrins and spectrins has been proposed to be key components. In particular, nodes of Ranvier themselves are enriched with ankyrinG (ankG) and ?IV spectrin; ankG is thought to bind directly to the Na+ and K+ channels, and then link to the actin cytoskeleton through ?IV spectrin. At paranodes, both ankyrinB and ?II spectrin are clustered, although their functions at paranodes remain unknown. Paranodes are also thought to function as a paranodal diffusion barrier and a second mechanism to mediate ion channel clustering at nodes, although the mechanisms responsible for this barrier function remain unknown. Furthermore, a major impediment to elucidating the function of paranodes is the relatively few proteins that have been identified at this site. In this proposal we will seek to determine the function of the nodal and paranodal cytoskeletons in node of Ranvier assembly and maintenance. We will do this using three new mouse models that utilize Cre-Lox technology to control the temporal and spatial (cell-type specific) expression of ankG, ankB, and ?II spectrin. We will silence expression of these proteins in peripheral sensory neurons, in retinal ganglion cells, and in myelinating glia during both development and in adults. Finally, we will use proteomic methods to identify new paranodal proteins, and then seek to determine their functions.