PINOID positively regulates auxin efflux in Arabidopsis root hair cells and tobacco cells
PINOID positively regulates auxin efflux in Arabidopsis root hair cells and tobacco cells
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DOI：
10.1105/tpc.105.035972
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发表时间：
2006-07-01
期刊：
影响因子：
11.6
通讯作者：
Cho, Hyung-Taeg
中科院分区：
文献类型：
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作者：
Lee, Sang Ho;Cho, Hyung-Taeg
生长素的细胞间转运由质膜中的流入和流出载体介导，并受到发育和环境调节。在这里，利用生长素敏感的拟南芥根毛细胞系统和烟草（Nicotiana tabacum）悬浮细胞系统，我们证明了蛋白激酶PINOID（PID）正向调节生长素流出。 PID (PIDox) 或生长素流出载体成分 PINFORMED3 (PIN3, PIN3ox) 的过度表达，特别是在根毛细胞中，极大地抑制了根毛的生长。在 PIDox 和 PIN3ox 转化体中，通过添加生长素、蛋白激酶抑制剂或生长素流出抑制剂，根毛生长几乎恢复到野生型水平。 PID 或 PIN3 在细胞边界的定位被布雷菲德菌素 A 和十字孢菌素破坏。激酶结构域的突变消除了 PID 定位于细胞边界并抑制根毛生长的能力。这些结果表明，PIDox-或PIN3ox-增强的生长素流出导致细胞内生长素的短缺，并随后抑制根毛生长。在使用转基因烟草悬浮细胞的生长素流出测定中，PIDox 或 PIN3ox 也增强了生长素流出。总的来说，这些结果表明 PID 正向调节细胞生长素流出，最有可能是通过调节 PIN 和/或参与生长素流出的一些其他分子伙伴的运输。
Intercellular transport of auxin is mediated by influx and efflux carriers in the plasma membrane and subjected to developmental and environmental regulation. Here, using the auxin-sensitive Arabidopsis thaliana root hair cell system and the tobacco ( Nicotiana tabacum) suspension cell system, we demonstrate that the protein kinase PINOID (PID) positively regulates auxin efflux. Overexpression of PID (PIDox) or the auxin efflux carrier component PINFORMED3 (PIN3, PIN3ox), specifically in the root hair cell, greatly suppressed root hair growth. In both PIDox and PIN3ox transformants, root hair growth was nearly restored to wild-type levels by the addition of auxin, protein kinase inhibitors, or auxin efflux inhibitors. Localization of PID or PIN3 at the cell boundary was disrupted by brefeldin A and staurosporine. A mutation in the kinase domain abrogated the ability of PID to localize at the cell boundary and to inhibit root hair growth. These results suggest that PIDox- or PIN3ox- enhanced auxin efflux results in a shortage of intracellular auxin and a subsequent inhibition of root hair growth. In an auxin efflux assay using transgenic tobacco suspension cells, PIDox or PIN3ox also enhanced auxin efflux. Collectively, these results suggest that PID positively regulates cellular auxin efflux, most likely by modulating the trafficking of PIN and/or some other molecular partners involved in auxin efflux.