An early secretory pathway mediated by GNOM-LIKE 1 and GNOM is essential for basal polarity establishment in Arabidopsis thaliana
An early secretory pathway mediated by GNOM-LIKE 1 and GNOM is essential for basal polarity establishment in Arabidopsis thaliana
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DOI：
10.1073/pnas.1424856112
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发表时间：
2015-02-17
影响因子：
11.1
通讯作者：
Robert, Stephanie
中科院分区：
文献类型：
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作者：
Doyle, Siamsa M.;Haeger, Ash;Robert, Stephanie
植物激素吲哚-3-乙酸（IAA，或生长素）的空间调节对植物发育至关重要。生长素梯度的建立是由极性定位的生长素转运体介导的，包括PIN- formed （PIN）蛋白。它们在质膜上的定位和丰度受到膜内机制的严格调控，特别是由ADP核糖基化因子鸟嘌呤核苷酸交换因子（ARF-GEF） GNOM介导的内吞和再循环途径。我们通过药理学和遗传学方法评估了早期分泌途径在拟南芥PIN1极性建立中的作用。我们发现了一种化合物ES8 (endosidin 8)，它选择性地干扰PIN1的基底极性，而不改变顶端蛋白的极性。ES8改变了生长素在根中的分布模式，并诱导了强烈的发育表型，包括根长缩短。arf - gef缺陷突变体gnm -样1 （gnl1-1）和gnm （van7）对ES8具有显著抗性。该化合物不影响PIN1的再循环或空泡运输，但会导致其在细胞内积聚，导致质膜处PIN1基本极性的丧失。我们的数据证实了GNOM在内质网(ER)-高尔基体运输中的作用，并揭示了GNL1/GNOM介导的早期分泌途径选择性地调节PIN1基本极性的建立，这种方式对正常植物发育至关重要。
Spatial regulation of the plant hormone indole-3-acetic acid (IAA, or auxin) is essential for plant development. Auxin gradient establishment is mediated by polarly localized auxin transporters, including PIN-FORMED (PIN) proteins. Their localization and abundance at the plasma membrane are tightly regulated by endo-membrane machinery, especially the endocytic and recycling pathways mediated by the ADP ribosylation factor guanine nucleotide exchange factor (ARF-GEF) GNOM. We assessed the role of the early secretory pathway in establishing PIN1 polarity in Arabidopsis thaliana by pharmacological and genetic approaches. We identified the compound endosidin 8 (ES8), which selectively interferes with PIN1 basal polarity without altering the polarity of apical proteins. ES8 alters the auxin distribution pattern in the root and induces a strong developmental phenotype, including reduced root length. The ARF-GEF-defective mutants gnom-like 1 (gnl1-1) and gnom (van7) are significantly resistant to ES8. The compound does not affect recycling or vacuolar trafficking of PIN1 but leads to its intracellular accumulation, resulting in loss of PIN1 basal polarity at the plasma membrane. Our data confirm a role for GNOM in endoplasmic reticulum (ER)-Golgi trafficking and reveal that a GNL1/GNOM-mediated early secretory pathway selectively regulates PIN1 basal polarity establishment in a manner essential for normal plant development.