Plasma membrane-bound AGC3 kinases phosphorylate PIN auxin carriers at TPRXS(N/S) motifs to direct apical PIN recycling
Plasma membrane-bound AGC3 kinases phosphorylate PIN auxin carriers at TPRXS(N/S) motifs to direct apical PIN recycling
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DOI：
10.1242/dev.052456
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发表时间：
2010-10-01
期刊：
影响因子：
4.6
通讯作者：
Offringa, Remko
中科院分区：
文献类型：
--
作者：
Dhonukshe, Pankaj;Huang, Fang;Offringa, Remko
极性膜货物输送对于建立细胞极性和定向运输过程至关重要。在植物中，极性运输介导 PIN FORMED (PIN) 载体的动态不对称分布，驱动生长素激素的极性细胞间运输，从而产生控制发育的生长素最大值和最小值。拟南芥PINOID (PID) 蛋白激酶通过磷酸化PIN 来指导顶端PIN 定位。在这里，我们将 PID 同系物 WAG1 和 WAG2 确定为新的 PIN 极性调节器。我们表明，AGC3 激酶 PID、WAG1 和 WAG2（而非其他植物 AGC 激酶）通过磷酸化 PIN 中央亲水环内三个保守的 TPRXS(N/S) 基序中的中间丝氨酸，指示将 PIN 募集到顶端循环途径中。我们的结果提出了一个模型，在默认的非极性 PIN 分泌后，非极性定位的 PID、WAG1 和 WAG2 在质膜上磷酸化 PIN，并触发内吞作用依赖性顶端 PIN 回收。这种磷酸化触发的顶端 PIN 回收与 ARF-GEF GNOM 依赖的基础回收竞争，以促进顶端 PIN 定位。在植物中，PID、WAG1 和 WAG2 的表达域与这些细胞类型中 PIN 的顶端定位相关，表明这些激酶对于顶端 PIN 定位的重要性。我们的数据表明，通过指导极性 PIN 定位和 PIN 介导的极性生长素运输，三种 AGC3 激酶冗余地调节子叶发育、根分生组织大小和向重力反应，表明它们参与程序性和适应性植物发育。
Polar membrane cargo delivery is crucial for establishing cell polarity and for directional transport processes. In plants, polar trafficking mediates the dynamic asymmetric distribution of PIN FORMED (PIN) carriers, which drive polar cell-to-cell transport of the hormone auxin, thereby generating auxin maxima and minima that control development. The Arabidopsis PINOID (PID) protein kinase instructs apical PIN localization by phosphorylating PINs. Here, we identified the PID homologs WAG1 and WAG2 as new PIN polarity regulators. We show that the AGC3 kinases PID, WAG1 and WAG2, and not other plant AGC kinases, instruct recruitment of PINs into the apical recycling pathway by phosphorylating the middle serine in three conserved TPRXS(N/S) motifs within the PIN central hydrophilic loop. Our results put forward a model by which apolarly localized PID, WAG1 and WAG2 phosphorylate PINs at the plasma membrane after default non-polar PIN secretion, and trigger endocytosis-dependent apical PIN recycling. This phosphorylation-triggered apical PIN recycling competes with ARF-GEF GNOM-dependent basal recycling to promote apical PIN localization. In planta, expression domains of PID, WAG1 and WAG2 correlate with apical localization of PINs in those cell types, indicating the importance of these kinases for apical PIN localization. Our data show that by directing polar PIN localization and PIN-mediated polar auxin transport, the three AGC3 kinases redundantly regulate cotyledon development, root meristem size and gravitropic response, indicating their involvement in both programmed and adaptive plant development.