Polar-localized NPH3-like proteins regulate polarity and endocytosis of PIN-FORMED auxin efflux carriers
Polar-localized NPH3-like proteins regulate polarity and endocytosis of PIN-FORMED auxin efflux carriers
复制标题
DOI：
10.1242/dev.057745
复制
发表时间：
2011-05-15
期刊：
影响因子：
4.6
通讯作者：
Tasaka, Masao
中科院分区：
文献类型：
--
作者：
Furutani, Masahiko;Sakamoto, Norihito;Tasaka, Masao
依赖于PIN-FORMED（PIN）的生长素运输对植物发育及其响应环境或内源信号的调节至关重要。一种非向光性下胚轴3（NPH3）样蛋白，MACCHI - BOU 4（MAB4），已被证明在器官形成过程中控制PIN1的定位，但其作用有限。拟南芥基因组包含四个基因，MAB4/ENP/NPY1 - LIKE1（MEL1）、MEL2、MEL3和MEL4，它们与MAB4高度同源。遗传分析揭示了MAB4和MEL基因在调控器官形成以及根的向重力性方面存在功能冗余，这表明NPH3家族蛋白的功能范围比之前所推测的更广泛。多个突变体显示PIN丰度和PIN极性定位严重降低，导致生长素响应标记DR5rev::GFP表达缺陷。药理学分析和光漂白后的荧光恢复实验表明，mel突变增加了PIN2从质膜的内化，但既不影响细胞内PIN2的运输，也不影响PIN2在质膜的侧向扩散。值得注意的是，所有MAB4亚家族蛋白在植物中都在细胞周边呈极性定位。MAB4的极性几乎与PIN的极性相同。我们的研究结果表明，MAB4亚家族蛋白以极性方式特异性地将PIN蛋白保留在质膜上，从而控制生长素的定向运输和植物发育。
PIN-FORMED (PIN)-dependent auxin transport is essential for plant development and its modulation in response to the environment or endogenous signals. A NON-PHOTOTROPIC HYPOCOTYL 3 (NPH3)-like protein, MACCHI-BOU 4 (MAB4), has been shown to control PIN1 localization during organ formation, but its contribution is limited. The Arabidopsis genome contains four genes, MAB4/ENP/NPY1-LIKE1 (MEL1), MEL2, MEL3 and MEL4, highly homologous to MAB4. Genetic analysis disclosed functional redundancy between MAB4 and MEL genes in regulation of not only organ formation but also of root gravitropism, revealing that NPH3 family proteins have a wider range of functions than previously suspected. Multiple mutants showed severe reduction in PIN abundance and PIN polar localization, leading to defective expression of an auxin responsive marker DR5rev::GFP. Pharmacological analyses and fluorescence recovery after photo-bleaching experiments showed that mel mutations increase PIN2 internalization from the plasma membrane, but affect neither intracellular PIN2 trafficking nor PIN2 lateral diffusion at the plasma membrane. Notably, all MAB4 subfamily proteins show polar localization at the cell periphery in plants. The MAB4 polarity was almost identical to PIN polarity. Our results suggest that the MAB4 subfamily proteins specifically retain PIN proteins in a polarized manner at the plasma membrane, thus controlling directional auxin transport and plant development.