Arabidopsis translation initiation factors eIFiso4G1/2 link repression of mRNA cap-binding complex eIFiso4F assembly with RNA-binding protein SOAR1-mediated ABA signaling
Arabidopsis translation initiation factors eIFiso4G1/2 link repression of mRNA cap-binding complex eIFiso4F assembly with RNA-binding protein SOAR1-mediated ABA signaling
复制标题
拟南芥翻译起始因子 eIFiso4G1/2 将抑制 mRNA 帽结合复合物 eIFiso4F 组装与 RNA 结合蛋白 SOAR1 介导的 ABA 信号传导联系起来
DOI：
10.1111/nph.15880
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发表时间：
2019-08-01
期刊：
影响因子：
9.4
通讯作者：
Zhang, Da-Peng
中科院分区：
文献类型：
--
作者：
Bi, Chao;Ma, Yu;Zhang, Da-Peng
翻译起始因子eIF4E结合蛋白通过干扰mRNA帽结合复合体eIF4F的组装来调节蛋白质翻译，在哺乳动物和酵母细胞中得到了很好的描述。然而，目前尚不清楚信号调节因子或信号通路是否直接与任何翻译起始因子相互作用来调节eIF4F在植物细胞中的组装。在这里，我们报道了拟南芥eIF4G的两个亚型，eIFso4G1和eIFiso4G2，与细胞质-核双定位的五肽重复蛋白SOAR1相互作用，调节脱落酸(ABA)信号。SOAR1抑制eIFso4E、eIF4Es、eIF4A1、eIF4B2和Polyy(A)结合蛋白PAB6与eIFso4G1和eIFso4G2的相互作用，从而抑制eIFiso4F/混合eIF4F的组装和抑制翻译起始。SOAR1结合一个关键的ABA反应基因ABI5的mRNA，并与eIFiso4G1/2协同抑制ABI5的翻译。SOAR1与ABI5 mRNA的结合可能抑制了SOAR1与eIFiso4G1/2的相互作用，表明存在调控环。我们的发现发现了一个新的翻译起始抑制物干扰帽结合复合体组装，并在帽结合复合体组装和ABA信号之间建立了联系。
The translation initiation factor eIF4E-binding protein-mediated regulation of protein translation by interfering with assembly of mRNA cap-binding complex eIF4F is well described in mammalian and yeast cells. However, it remains unknown whether a signaling regulator or pathway interacts directly with any translation initiation factor to modulate assembly of eIF4F in plant cells. Here, we report that the two isoforms of Arabidopsis eIF4G, eIFiso4G1 and eIFiso4G2, interact with a cytoplasmic-nuclear dual-localized pentatricopeptide repeat protein SOAR1 to regulate abscisic acid (ABA) signaling. SOAR1 inhibits interactions of eIFiso4E, eIF4Es, eIF4A1, eIF4B2 and poly(A)-binding protein PAB6 with eIFiso4G1 and eIFiso4G2, thereby inhibiting eIFiso4F/mixed eIF4F assembly and repressing translation initiation. SOAR1 binds mRNA of a key ABA-responsive gene ABI5 and cooperates with eIFiso4G1/2 to repress translation of ABI5. The binding of SOAR1 to ABI5 mRNA is likely to inhibit the interaction of SOAR1 with eIFiso4G1/2, suggesting a regulatory loop. Our findings identify a novel translation initiation repressor interfering with cap-binding complex assembly, and establish a link between cap-binding complex assembly and ABA signaling.