Analysis on the developmental changes in molecular architecture of active zones

生长锥是一种生长中的神经末梢，它主动地向靶细胞延伸，在靶细胞处它转化为突触。生长锥的主动延伸伴随着表面膜的扩张，这可能是由表面膜和生长锥中的囊泡之间的膜融合介导的。通过F-actin覆盖分析，我们最近发现了四种蛋白质，分别命名为Neurabin I，Neurabin II，Afadin和AF-6，它们具有一个PDZ结构域，定位于突触。在神经元中引入Neurabin I反义RNA导致轴突生长的抑制。Afadin和AF-6定位于粘附连接和突触。这些结果表明，Neurabin I，Neurabin II，Afadin和AF-6可能作为新的粘附系统在粘附连接和突触中起作用。我们还发现了一种新的蛋白质Tomosin，它与突触融合蛋白结合，可能调节突触和生长锥中的膜融合机制。

The growth cone is a growing nerve tip that actively elongates toward the target cells at which it transforms into the synapse. The active extension of the growth cone is accompanied by expansion of the surface membrane that is probably mediated by the membrane fusion between the surface membrane and that of vesicles in the growth cone. By using F-actin overlay assay, we have recently found four proteins and named them as Neurabin I,Neurabin II,Afadin, and AF-6, which have one PDZ domain and are localized at synapses. Introduction of Neurabin I antisense RNA in neurons resulted in inhibition of neurite outgrowth. Afadin and AF-6 were localized at both adherens junctions and synapses. These results suggests that Neurabin I,Neurabin II,Afadin, and AF-6 may function as new adhesive systems at both adherens junctions and synapses. We have also found a new protein, Tomosin, which binds to syntaxin and may regulate the membrane fusion machinery in synapses as well as in the growth cones.