Department of General and Environmental Physiology and Centre of Excellence in Comparative Genomics CEGBA, University of Bari, I-70126 Bari, Italy.
Neuroscience. 2010 Jul 28;168(4):903-14. doi: 10.1016/j.neuroscience.2010.02.008. Epub 2010 Feb 11.
Unlike other mammalian AQPs, multiple tetramers of AQP4 associate in the plasma membrane to form peculiar structures called Orthogonal Arrays of Particles (OAPs), that are observable by freeze-fracture electron microscopy (FFEM). However, FFEM cannot give information about the composition of OAPs of different sizes, and due to its technical complexity is not easily applicable as a routine technique. Recently, we employed the 2D gel electrophoresis BN-SDS/PAGE that for the first time enabled the biochemical isolation of AQP4-OAPs from several tissues. We found that AQP4 protein is present in several higher-order complexes (membrane pools of supra-structures) which contain different ratios of M1/M23 isoforms corresponding to AQP4-OAPs of different size. In this paper, we illustrate in detail the potentiality of 2D BN/SDS-PAGE for analyzing AQP4 supra-structures, their relationship with the dystrophin glycoprotein complex and other membrane proteins, and their role as a specific target of Neuromyelitis Optica autoantibodies.
与其他哺乳动物 AQPs 不同，AQP4 多聚体在质膜中聚集形成称为正交排列颗粒（OAPs）的特殊结构，可通过冷冻断裂电子显微镜（FFEM）观察到。然而，FFEM 无法提供关于不同大小 OAPs 组成的信息，并且由于其技术复杂性，不易作为常规技术应用。最近，我们采用了 2D 凝胶电泳 BN-SDS/PAGE，这是首次能够从几种组织中生化分离 AQP4-OAPs。我们发现 AQP4 蛋白存在于几种更高阶的复合物（超结构的膜池）中，这些复合物包含不同比例的 M1/M23 同工型，对应于不同大小的 AQP4-OAPs。在本文中，我们详细说明了 2D BN/SDS-PAGE 分析 AQP4 超结构的潜力，及其与营养不良性肌病糖蛋白复合物和其他膜蛋白的关系，以及作为视神经脊髓炎自身抗体的特异性靶标。
