Signal motif-dependent ER export of the Qc-SNARE BET12 interacts with MEMB12 and affects PR1 trafficking in Arabidopsis
Signal motif-dependent ER export of the Qc-SNARE BET12 interacts with MEMB12 and affects PR1 trafficking in Arabidopsis
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Qc-SNARE BET12 的信号基序依赖性 ER 输出与 MEMB12 相互作用并影响拟南芥中 PR1 的运输
DOI：
10.1242/jcs.202838
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发表时间：
2018-01-01
影响因子：
4
通讯作者：
Jiang, Liwen
中科院分区：
文献类型：
--
作者：
Chung, Kin Pan;Zeng, Yonglun;Jiang, Liwen
可溶性N-乙基马来酰亚胺敏感性融合蛋白附着蛋白受体（SNARE）因其在控制膜融合中的作用而众所周知，膜融合是真核生物中囊泡运输的最后但关键的步骤。SNARE蛋白参与多种生物学过程，包括病原体防御和通道活性调节，以及植物生长和发育。将SNARE蛋白精确靶向到指定隔室是其正常发挥功能的先决条件。然而，植物中SNARE靶向的潜在机制仍然不清楚。在这里，我们研究了拟南芥Qc-SNARE BET12的靶向机制，它参与了早期分泌途径中的蛋白质运输。鉴定了有效BET12 ER输出所需的两个不同的信号基序。下拉测定和体内成像暗示COPI和COPII途径都是BET 12靶向所需的。使用ER-输出缺陷形式的BET 12的进一步研究表明，高尔基体定位的Qb-SNARE MEMB 12，一种病程相关蛋白1（PR 1; At2g14610）分泌的负调节因子，是其相互作用的伴侣。BET12的异位表达对ER-高尔基体的顺行转运没有抑制作用，但引起了PR 1的细胞内积累，表明BET12在A. thaliana.
Soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptors (SNAREs) are well-known for their role in controlling membrane fusion, the final, but crucial step, in vesicular transport in eukaryotes. SNARE proteins contribute to various biological processes including pathogen defense and channel activity regulation, as well as plant growth and development. Precise targeting of SNARE proteins to destined compartments is a prerequisite for their proper functioning. However, the underlying mechanism(s) for SNARE targeting in plants remains obscure. Here, we investigate the targeting mechanism of the Arabidopsis thaliana Qc-SNARE BET12, which is involved in protein trafficking in the early secretory pathway. Two distinct signal motifs that are required for efficient BET12 ER export were identified. Pulldown assays and in vivo imaging implicated that both the COPI and COPII pathways were required for BET12 targeting. Further studies using an ER-export-defective form of BET12 revealed that the Golgi-localized Qb-SNARE MEMB12, a negative regulator of pathogenesis-related protein 1 (PR1; At2g14610) secretion, was its interacting partner. Ectopic expression of BET12 caused no inhibition in the general ER-Golgi anterograde transport but caused intracellular accumulation of PR1, suggesting that BET12 has a regulatory role in PR1 trafficking in A. thaliana.