Fluorescent castasterone reveals BRI1 signaling from the plasma membrane
Fluorescent castasterone reveals BRI1 signaling from the plasma membrane
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DOI：
10.1038/nchembio.958
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发表时间：
2012-06-01
影响因子：
14.8
通讯作者：
Russinova, Eugenia
中科院分区：
文献类型：
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作者：
Irani, Niloufer G.;Di Rubbo, Simone;Russinova, Eugenia
受体介导的内吞作用是信号转导的一个组成部分，因为它介导信号衰减并为信号事件提供空间和时间维度。植物中研究最充分的富含亮氨酸重复受体样激酶之一，油菜素类固醇不敏感 1 (BRI1)，在细胞表面感知其配体油菜素类固醇 (BR) 激素，并被组成型内吞。然而，内吞作用对于 BR 信号传导的重要性仍不清楚。在这里，我们开发了一种生物活性荧光 BR 类似物 Alexa Fluor 647-castasterone (AFCS)，并可视化了活拟南芥细胞中 BRI1-AFCS 复合物的内吞作用。依赖于网格蛋白和 ARF GTPases (ARF-GEF) 的鸟嘌呤核苷酸交换因子 (ARF-GEF) 的内吞作用受损 GNOM 通过在质膜上保留活性 BRI1-配体复合物来增强 BR 信号传导。增加 BRI1-BR 复合物的跨高尔基体网络/早期内体库不会影响 BR 信号传导。据我们所知，我们的研究结果首次实现了植物中受体-配体复合物的可视化，并揭示了质膜 BR 信号传导的网格蛋白和 ARF-GEF 依赖性内吞调节。
Receptor-mediated endocytosis is an integral part of signal transduction as it mediates signal attenuation and provides spatial and temporal dimensions to signaling events. One of the best-studied leucine-rich repeat receptor-like kinases in plants, BRASSINOSTEROID INSENSITIVE 1 (BRI1), perceives its ligand, the brassinosteroid (BR) hormone, at the cell surface and is constitutively endocytosed. However, the importance of endocytosis for BR signaling remains unclear. Here we developed a bioactive, fluorescent BR analog, Alexa Fluor 647-castasterone (AFCS), and visualized the endocytosis of BRI1-AFCS complexes in living Arabidopsis thaliana cells. Impairment of endocytosis dependent on clathrin and the guanine nucleotide exchange factor for ARF GTPases (ARF-GEF) GNOM enhanced BR signaling by retaining active BRI1-ligand complexes at the plasma membrane. Increasing the trans-Golgi network/early endosome pool of BRI1-BR complexes did not affect BR signaling. Our findings provide what is to our knowledge the first visualization of receptor-ligand complexes in plants and reveal clathrin- and ARF-GEF-dependent endocytic regulation of BR signaling from the plasma membrane.