The plant ESCRT component FREE1 shuttles to the nucleus to attenuate abscisic acid signalling
The plant ESCRT component FREE1 shuttles to the nucleus to attenuate abscisic acid signalling
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植物 ESCRT 成分 FREE1 穿梭至细胞核以减弱脱落酸信号传导。
DOI：
10.1038/s41477-019-0400-5
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发表时间：
2019-05-01
期刊：
影响因子：
18
通讯作者：
Gao, Caiji
中科院分区：
文献类型：
--
作者：
Li, Hongbo;Li, Yingzhu;Gao, Caiji
运输所需的内体分选复合体（ESCRT）机械其在真核生物内体分选中的功能已得到充分记录。在这里，我们展示了植物中 ESCRT 成分迄今为止未知的非内体功能。我们发现，内体分选所需的 FYVE 结构域蛋白 1 (FREE1) 是一种最近发现的植物特异性 ESCRT 成分，对于多囊泡体生物发生至关重要，它在细胞核中脱落酸 (ABA) 信号传导的转录抑制中发挥附加功能。 ABA 处理后，SNF1 相关蛋白激酶 2 (SnRK2) 激酶磷酸化 FREE1，这是 ABA 诱导 FREE1 入核的必要步骤。在细胞核中，FREE1 与碱性亮氨酸拉链转录因子 ABA-RESPONSIVE ELEMENTS BINDING FACTOR4 和 ABA-INSENSITIVE5 相互作用，减少它们与下游基因顺式调控序列的结合。总的来说，我们的研究证明了内膜运输和 ABA 信号在转录水平上的串扰，并强调了植物 ESCRT 亚基 FREE1 的兼职特性，该亚基除了在细胞质中的膜运输中发挥作用外，还在细胞核中进化出了独特的非内体功能。
The endosomal sorting complex required for transport (ESCRT) machinery has been well documented for its function in endosomal sorting in eukaryotes. Here, we demonstrate an up-to-now unknown and non-endosomal function of the ESCRT component in plants. We show that FYVE DOMAIN PROTEIN REQUIRED FOR ENDOSOMAL SORTING 1 (FREE1), a recently identified plant-specific ESCRT component essential for multivesicular body biogenesis, plays additional functions in the nucleus in transcriptional inhibition of abscisic acid (ABA) signalling. Following ABA treatment, SNF1-related protein kinase 2 (SnRK2) kinases phosphorylate FREE1, a step requisite for ABA-induced FREE1 nuclear import. In the nucleus, FREE1 interacts with the basic leucine zipper transcription factors ABA-RESPONSIVE ELEMENTS BINDING FACTOR4 and ABA-INSENSITIVE5 to reduce their binding to the cis-regulatory sequences of downstream genes. Collectively, our study demonstrates the crosstalk between endomembrane trafficking and ABA signalling at the transcriptional level and highlights the moonlighting properties of the plant ESCRT subunit FREE1, which has evolved unique non-endosomal functions in the nucleus besides its roles in membrane trafficking in the cytoplasm.