Most eukaryotic cells are polarized. Common toolbox regulating cell polarization includes Rho guanosine triphosphatases (GTPases), in which spatiotemporal activation is regulated by a plethora of regulators. Rho of plants (ROPs) are the only Rho GTPases in plants. Although vesicular trafficking was hinted in the regulation of ROPs, it was unclear where vesicle‐carried ROP starts, whether it is dynamically regulated, and which components participate in vesicle‐mediated ROP targeting. In addition, although vesicle trafficking and guanine nucleotide inhibitor (GDI) pathways in Rho signaling have been extensively studied in yeast, it is unknown whether the two pathways interplay. Unclear are also cellular and developmental consequences of their interaction in multicellular organisms. Here, we show that the dynamic targeting of ROP through vesicles requires coat protein complex II and ADP‐ribosylation factor 1‐mediated post‐Golgi trafficking. Trafficking of vesicle‐carried ROPs between the plasma membrane and the trans‐Golgi network is mediated through adaptor protein 1 and sterol‐mediated endocytosis. Finally, we show that GDI and vesicle trafficking synergistically regulate cell polarization and ROP targeting, suggesting that the establishment and maintenance of cell polarity is regulated by an evolutionarily conserved mechanism.

中文翻译：

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植物鸟苷三磷酸酶Rho的靶向和信号传导需要鸟嘌呤核苷酸抑制剂和水泡运输之间的协同相互作用

大多数真核细胞是极化的。调节细胞极化的常用工具箱包括Rho鸟苷三磷酸酶（GTPases），其中时空活化受多种调节剂调节。植物Rho（ROP）是植物中唯一的Rho GTPases。尽管在ROPs的调节中暗示了水泡运输，但尚不清楚水泡运载的ROP从何处开始，是否动态调节以及哪些成分参与水泡介导的ROP靶向。另外，尽管已经在酵母中广泛研究了Rho信号传导中的囊泡运输和鸟嘌呤核苷酸抑制剂（GDI）途径，但是尚不清楚这两种途径是否相互作用。还不清楚它们在多细胞生物中相互作用的细胞和发育后果。这里，我们显示通过小泡动态靶向ROP需要外壳蛋白复合物II和ADP核糖基化因子1介导的高尔基体后运输。在质膜和细胞膜之间运输囊状ROPs反式高尔基体网络是通过衔接蛋白1和固醇介导的内吞作用介导的。最后，我们显示GDI和囊泡运输协同调节细胞极化和ROP靶向，这表明细胞极性的建立和维持受进化上保守机制的调节。