Functional Analysis of the Hydrophilic Loop in Intracellular Trafficking of Arabidopsis PIN-FORMED Proteins
Functional Analysis of the Hydrophilic Loop in Intracellular Trafficking of Arabidopsis PIN-FORMED Proteins
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DOI：
10.1105/tpc.113.118422
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发表时间：
2014-04-01
期刊：
影响因子：
11.6
通讯作者：
Cho, Hyung-Taeg
中科院分区：
文献类型：
--
作者：
Ganguly, Anindya;Park, Minho;Cho, Hyung-Taeg
不同的PIN形成蛋白（PIN）有助于细胞间和细胞内的生长素运输，这取决于它们独特的亚细胞定位。具有长亲水环（HL）的拟南芥PIN（PIN 1至PIN 4和PIN 7;长PIN）主要定位于质膜（PM），而短PIN（PIN 5和PIN 8）主要定位于内部隔室。然而，已观察到短PIN的亚细胞定位主要是针对在不同细胞类型中异位表达的PIN，并且HL在PIN运输中的作用仍不清楚。在这里，我们测试了是否一个长的PIN-HL可以提供其原始的分子线索，以一个短的PIN通过移植的HL。移植的长PIN 2-HL足以磷酸化和PM运输嵌合PIN 5：PIN 2-HL，但不能提供PIN 2的特征极性。与以前的观察结果不同，PIN 5在不同的细胞类型中显示出明显的PM定位，其中PIN 5天然或异位表达，甚至在一种细胞类型中显示出极性PM定位。此外，在根表皮中，根据发育阶段，PIN 5的亚细胞定位从PM切换到内部隔室。我们的研究结果表明，长PIN HL是部分模块的PIN的贩运行为和PIN的细胞内贩运是塑料取决于细胞类型和发育阶段。
Different PIN-FORMED proteins (PINs) contribute to intercellular and intracellular auxin transport, depending on their distinctive subcellular localizations. Arabidopsis thaliana PINs with a long hydrophilic loop (HL) (PIN1 to PIN4 and PIN7; long PINs) localize predominantly to the plasma membrane (PM), whereas short PINs (PIN5 and PIN8) localize predominantly to internal compartments. However, the subcellular localization of the short PINs has been observed mostly for PINs ectopically expressed in different cell types, and the role of the HL in PIN trafficking remains unclear. Here, we tested whether a long PIN-HL can provide its original molecular cues to a short PIN by transplanting the HL. The transplanted long PIN2-HL was sufficient for phosphorylation and PM trafficking of the chimeric PIN5: PIN2-HL but failed to provide the characteristic polarity of PIN2. Unlike previous observations, PIN5 showed clear PM localization in diverse cell types where PIN5 is natively or ectopically expressed and even polar PM localization in one cell type. Furthermore, in the root epidermis, the subcellular localization of PIN5 switched from PM to internal compartments according to the developmental stage. Our results suggest that the long PIN-HL is partially modular for the trafficking behavior of PINs and that the intracellular trafficking of PIN is plastic depending on cell type and developmental stage.