Bellen H J, Lu Y, Beckstead R, Bhat M A
Dept of Human and Molecular Genetics, Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA.
Trends Neurosci. 1998 Oct;21(10):444-9. doi: 10.1016/s0166-2236(98)01267-3.
Axonal insulation is of key importance for the proper propagation of action potentials. In Drosophila and other invertebrates, it has recently been demonstrated that septate junctions play an essential role in axonal insulation or blood-brain-barrier formation. Neurexin IV, a molecular component of Drosophila septate junctions, has been shown to be essential for axonal insulation in the PNS in embryos and larvae. Interestingly, a vertebrate homolog of Neurexin IV, caspr--also named paranodin--has been shown to localize to septate-like junctional structures. These vertebrate junctions are localized to the paranodal region of the nodes of Ranvier, between axons and Schwann cells. Caspr/paranodin might play an important role in barrier formation, and link neuronal membrane components with the axonal cytoskeletal network.
轴突绝缘对于动作电位的正常传导至关重要。在果蝇和其他无脊椎动物中，最近已证明隔膜连接在轴突绝缘或血脑屏障形成中起重要作用。神经连接蛋白IV是果蝇隔膜连接的一种分子成分，已被证明对胚胎和幼虫外周神经系统中的轴突绝缘至关重要。有趣的是，神经连接蛋白IV的脊椎动物同源物，即接触蛋白相关蛋白（Caspr）——也称为副结节蛋白——已被证明定位于类似隔膜的连接结构。这些脊椎动物的连接位于郎飞结的旁结区域，在轴突和施万细胞之间。Caspr/副结节蛋白可能在屏障形成中起重要作用，并将神经元膜成分与轴突细胞骨架网络连接起来。
