Axon guidance relies on a combinatorial code of receptor and ligand interactions that direct adhesive/attractive and repulsive cellular responses. Recent structural data have revealed many of the molecular mechanisms that govern these interactions and enabled the design of sophisticated mutant tools to dissect their biological functions. Here, we discuss the structure/function relationships of four major classes of guidance cues (ephrins, semaphorins, slits, netrins) and examples of morphogens (Wnt, Shh) and of cell adhesion molecules (FLRT). These cell signaling systems rely on specific modes of receptor-ligand binding that are determined by selective binding sites; however, defined structure-encoded receptor promiscuity also enables cross talk between different receptor/ligand families and can also involve extracellular matrix components. A picture emerges in which a multitude of highly context-dependent structural assemblies determines the finely tuned cellular behavior required for nervous system development.

中文翻译：

---

轴突引导的结构视角。


轴突引导依赖于受体和配体相互作用的组合代码，指导粘附/吸引和排斥细胞反应。最近的结构数据揭示了许多控制这些相互作用的分子机制，并使复杂的突变工具的设计能够剖析它们的生物学功能。在这里，我们讨论四大类引导信号（ephrins、semaphorins、slits、netrins）的结构/功能关系以及形态发生素（Wnt、Shh）和细胞粘附分子（FLRT）的示例。这些细胞信号系统依赖于由选择性结合位点决定的受体-配体结合的特定模式。然而，定义的结构编码受体混杂也会导致不同受体/配体家族之间的串扰，并且还可能涉及细胞外基质成分。一幅图画出现了，其中大量高度依赖环境的结构组件决定了神经系统发育所需的精细调整的细胞行为。