AtSNX1 defines an endosome for auxin-carrier trafficking in Arabidopsis
AtSNX1 defines an endosome for auxin-carrier trafficking in Arabidopsis
复制标题
DOI：
10.1038/nature05046
复制
发表时间：
2006-09-07
期刊：
影响因子：
64.8
通讯作者：
Gaude, Thierry
中科院分区：
文献类型：
--
作者：
Jaillais, Yvon;Fobis-Loisy, Isabelle;Gaude, Thierry
植物激素生长素及其载体在细胞内的极化分布对植物的正常生长发育至关重要。生长素的极性运输(1，2)由生长素流入(AUX)(3)和外流(PIN)(1，2，4-6)载体网络维持。生长素运输和PIN蛋白在质膜和内体之间的循环都需要内体GNOM(1，2，7，8)的活性；然而，这些载体所走的细胞内路线在很大程度上仍不清楚。在这里，我们证明了拟南芥分离连接蛋白1(AtSNX1)参与了生长素途径，并且PIN2，而不是Pin1或AUX1，通过含有AtSNX1的内体运输。我们证明了SNX1缺失突变体表现出多种与生长素相关的缺陷，并且AtSNX1功能的丧失严重增强了弱gnom突变体的表型。在根细胞中，我们进一步证明AtSNX1定位于与含有GNOM的内小体不同的内体隔室，并且在磷脂酰肌醇-3-羟基激酶抑制剂Wortmannin处理后或重力刺激后，PIN2在这个隔室积累。我们的数据揭示了参与PIN2内吞分选和植物发育的一个新的内体隔室的存在。
Polarized cellular distribution of the phytohormone auxin and its carriers is essential for normal plant growth and development. Polar auxin transport(1,2) is maintained by a network of auxin influx (AUX)(3) and efflux (PIN)(1,2,4-6) carriers. Both auxin transport and PIN protein cycling between the plasma membrane and endosomes require the activity of the endosomal GNOM(1,2,7,8); however, intracellular routes taken by these carriers remain largely unknown. Here we show that Arabidopsis thaliana SORTING NEXIN 1 (AtSNX1) is involved in the auxin pathway and that PIN2, but not PIN1 or AUX1, is transported through AtSNX1-containing endosomes. We demonstrate that the snx1-null mutant exhibits multiple auxin-related defects and that loss of function of AtSNX1 severely enhances the phenotype of a weak gnom mutant. In root cells, we further show that AtSNX1 localizes to an endosomal compartment distinct from GNOM-containing endosomes, and that PIN2 accumulates in this compartment after treatment with the phosphatidylinositol-3-OH kinase inhibitor wortmannin or after a gravity stimulus. Our data reveal the existence of a novel endosomal compartment involved in PIN2 endocytic sorting and plant development.