Department of Biochemistry, University of Oxford, Oxford, UK.
MeLis, University of Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5284, INSERM U1314, Institut NeuroMyoGène, 8 avenue Rockefeller 69008 Lyon, Lyon, France.
Cell. 2022 Oct 13;185(21):3931-3949.e26. doi: 10.1016/j.cell.2022.09.025.
Neural migration is a critical step during brain development that requires the interactions of cell-surface guidance receptors. Cancer cells often hijack these mechanisms to disseminate. Here, we reveal crystal structures of Uncoordinated-5 receptor D (Unc5D) in complex with morphogen receptor glypican-3 (GPC3), forming an octameric glycoprotein complex. In the complex, four Unc5D molecules pack into an antiparallel bundle, flanked by four GPC3 molecules. Central glycan-glycan interactions are formed by N-linked glycans emanating from GPC3 (N241 in human) and C-mannosylated tryptophans of the Unc5D thrombospondin-like domains. MD simulations, mass spectrometry and structure-based mutants validate the crystallographic data. Anti-GPC3 nanobodies enhance or weaken Unc5-GPC3 binding and, together with mutant proteins, show that Unc5/GPC3 guide migrating pyramidal neurons in the mouse cortex, and cancer cells in an embryonic xenograft neuroblastoma model. The results demonstrate a conserved structural mechanism of cell guidance, where finely balanced Unc5-GPC3 interactions regulate cell migration.
神经迁移是大脑发育过程中的一个关键步骤，需要细胞表面导向受体的相互作用。癌细胞经常劫持这些机制来扩散。在这里，我们揭示了未协调蛋白 5 受体 D（Unc5D）与形态发生素受体 GPC3 形成八聚体糖蛋白复合物的复合物的晶体结构。在该复合物中，四个 Unc5D 分子包装成一个反平行束，由四个 GPC3 分子侧翼。中央糖 - 糖相互作用是由源自 GPC3 的 N-连接聚糖（人 N241）和 Unc5D 血栓反应蛋白样结构域的 C-甘露糖化色氨酸形成的。MD 模拟、质谱和基于结构的突变体验证了晶体学数据。抗 GPC3 纳米抗体增强或削弱了 Unc5-GPC3 结合，并且与突变蛋白一起，表明 Unc5/GPC3 指导小鼠皮层中的迁移锥体神经元和胚胎异种移植物神经母细胞瘤模型中的癌细胞。结果表明，细胞导向的保守结构机制，其中精细平衡的 Unc5-GPC3 相互作用调节细胞迁移。
