Naphthylphthalamic acid associates with and inhibits PIN auxin transporters
Naphthylphthalamic acid associates with and inhibits PIN auxin transporters
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DOI：
10.1073/pnas.2020857118
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发表时间：
2021-01-05
影响因子：
11.1
通讯作者：
Hammes, Ulrich Z.
中科院分区：
文献类型：
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作者：
Abas, Lindy;Kolb, Martina;Hammes, Ulrich Z.
N-1-萘邻苯二甲酸（NPA）是植物生长素激素定向（极性）运输的关键抑制剂。几十年来，它一直是阐明植物生长和发育的独特极性生长素运输过程的关键工具。其确切的作用方式长期以来一直受到人们的关注，目前仍在辩论中，普遍的机械方案只描述了NPA和负责定向运输的主要运输者，即PIN生长素出口商之间的间接联系。在这里，我们提出的数据支持一个模型，其中NPA与PIN相关联的一个更直接的方式比迄今为止假设。我们表明，NPA抑制PIN活性在异源卵母细胞系统和NPA敏感的PIN在植物，酵母，卵母细胞膜的表达导致特定的饱和NPA结合。因此，我们建议PIN是真正的NPA目标。这为NPA抑制PIN依赖的生长素运输提供了一个简单的分子基础，并为NPA对植物生长的已知生理效应提供了一个合理的解释，以及解释过去和未来结果的另一种假设。我们还介绍了PIN二聚化，并描述了NPA对此的影响，这表明NPA的结合可以被利用来深入了解与其运输机制相关的PIN的结构方面。
N-1-naphthylphthalamic acid (NPA) is a key inhibitor of directional (polar) transport of the hormone auxin in plants. For decades, it has been a pivotal tool in elucidating the unique polar auxin transport-based processes underlying plant growth and development. Its exact mode of action has long been sought after and is still being debated, with prevailing mechanistic schemes describing only indirect connections between NPA and the main transporters responsible for directional transport, namely PIN auxin exporters. Here we present data supporting a model in which NPA associates with PINs in a more direct manner than hitherto postulated. We show that NPA inhibits PIN activity in a heterologous oocyte system and that expression of NPA-sensitive PINs in plant, yeast, and oocyte membranes leads to specific saturable NPA binding. We thus propose that PINs are a bona fide NPA target. This offers a straightforward molecular basis for NPA inhibition of PIN-dependent auxin transport and a logical parsimonious explanation for the known physiological effects of NPA on plant growth, as well as an alternative hypothesis to interpret past and future results. We also introduce PIN dimerization and describe an effect of NPA on this, suggesting that NPA binding could be exploited to gain insights into structural aspects of PINs related to their transport mechanism.