FYVE1/FREE1 Interacts with the PYL4 ABA Receptor and Mediates Its Delivery to the Vacuolar Degradation Pathway
FYVE1/FREE1 Interacts with the PYL4 ABA Receptor and Mediates Its Delivery to the Vacuolar Degradation Pathway
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DOI：
10.1105/tpc.16.00178
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发表时间：
2016-09-01
期刊：
影响因子：
11.6
通讯作者：
Rodriguez, Pedro L.
中科院分区：
文献类型：
--
作者：
Belda-Palazon, Borja;Rodriguez, Lesia;Rodriguez, Pedro L.
最近，我们描述了拟南芥质膜上RING E3泛素连接酶RSL 1对PYL 4和PYR 1的泛素化。这表明，泛素化脱落酸（阿坝）受体可能是针对液泡降解途径，因为这种泛素化通常是内吞途径的内化信号。在这里，我们表明，FYVE 1（以前称为FREE 1），最近描述的内体分选复合物所需的运输（ESCRT）机制的组成部分，与RSL 1受体复合物相互作用，并招募PYL 4的内体隔间。虽然ESCRT途径已被假定为保留的膜蛋白，我们表明参与这一途径的阿坝受体的降解，这可以与膜，但不是膜蛋白。敲低fyve 1等位基因对阿坝高度敏感，说明了ESCRT途径对阿坝信号调节的生物相关性。此外，fyve 1突变体在靶向阿坝受体进行液泡降解方面受损，导致PYL 4积累增加和对阿坝的响应增强。药理学和遗传学方法揭示了阿坝受体从质膜到内体/液泡降解途径的动态周转，这是由FYVE 1介导的，并依赖于RSL 1。该过程涉及网格蛋白介导的内吞作用和PYL 4通过ESCRT途径的运输，这有助于调节阿坝受体的周转并减弱阿坝信号传导。
Recently, we described the ubiquitylation of PYL4 and PYR1 by the RING E3 ubiquitin ligase RSL1 at the plasma membrane of Arabidopsis thaliana. This suggested that ubiquitylated abscisic acid (ABA) receptors might be targeted to the vacuolar degradation pathway because such ubiquitylation is usually an internalization signal for the endocytic route. Here, we show that FYVE1 (previously termed FREE1), a recently described component of the endosomal sorting complex required for transport (ESCRT) machinery, interacted with RSL1-receptor complexes and recruited PYL4 to endosomal compartments. Although the ESCRT pathway has been assumed to be reserved for integral membrane proteins, we show the involvement of this pathway in the degradation of ABA receptors, which can be associated with membranes but are not integral membrane proteins. Knockdown fyve1 alleles are hypersensitive to ABA, illustrating the biological relevance of the ESCRT pathway for the modulation of ABA signaling. In addition, fyve1 mutants are impaired in the targeting of ABA receptors for vacuolar degradation, leading to increased accumulation of PYL4 and an enhanced response to ABA. Pharmacological and genetic approaches revealed a dynamic turnover of ABA receptors from the plasma membrane to the endosomal/vacuolar degradation pathway, which was mediated by FYVE1 and was dependent on RSL1. This process involves clathrin-mediated endocytosis and trafficking of PYL4 through the ESCRT pathway, which helps to regulate the turnover of ABA receptors and attenuate ABA signaling.