Kordeli E
Biologie Cellulaire des Membranes, Institut Jacques Monod, CNRS, UMR 7592, Universités Paris 6/7, 75251 Paris-Cedex 05, France.
Microsc Res Tech. 2000 Apr 1;49(1):101-7. doi: 10.1002/(SICI)1097-0029(20000401)49:1<101::AID-JEMT11>3.0.CO;2-U.
Membrane skeletons, in particular the spectrin-based skeleton, are thought to participate in the organization of specialized membrane domains by restricting integral proteins to specific membrane sites. In the neuromuscular junction, discrete isoforms of spectrin and ankyrin, the peripheral protein that links spectrin to the membrane, colocalize with voltage-dependent sodium channels and N-CAM at the troughs of the postsynaptic membrane folds. Moreover, beta-spectrin, N-CAM, and sodium channels become clustered at the endplate during a period of time coincident with postsynaptic fold formation and synapse maturation. These observations suggest a role of the spectrin skeleton in directing and maintaining postsynaptic accumulations of sodium channels and N-CAM. In addition, the coexistence of spectrin and dystrophin at the troughs of the junctional folds raises the question of their respective functions in this membrane domain, where both cytoskeletal proteins have the potential to associate with sodium channels via ankyrin and syntrophin, respectively. Possible scenarios are discussed here with respect to accumulating evidence from studies of assembly of similar membrane domains in neurons.
膜骨架，尤其是基于血影蛋白的骨架，被认为通过将整合蛋白限制在特定的膜位点来参与特殊膜结构域的组织。在神经肌肉接头处，血影蛋白和锚蛋白（将血影蛋白连接到膜上的外周蛋白）的离散异构体与电压依赖性钠通道和N-CAM在突触后膜褶皱的凹陷处共定位。此外，β-血影蛋白、N-CAM和钠通道在与突触后褶皱形成和突触成熟同时发生的一段时间内聚集在终板处。这些观察结果表明血影蛋白骨架在指导和维持钠通道和N-CAM的突触后积累中起作用。此外，血影蛋白和肌营养不良蛋白在连接褶皱凹陷处的共存提出了它们在这个膜结构域中各自功能的问题，在这个膜结构域中，两种细胞骨架蛋白都有可能分别通过锚蛋白和肌萎缩蛋白相关蛋白与钠通道结合。本文结合来自神经元中类似膜结构域组装研究的越来越多的证据，讨论了可能的情况。
