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Arabidopsis translation initiation factors eIF iso4G1/2 link repression of mRNA cap‐binding complex eIF iso4F assembly with RNA ‐binding protein SOAR 1‐mediated ABA signaling
Author(s) -
Bi Chao,
Ma Yu,
Jiang ShangChuan,
Mei Chao,
Wang XiaoFang,
Zhang DaPeng
Publication year - 2019
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.15880
Subject(s) - eif4e , initiation factor , messenger rna , translation (biology) , eukaryotic translation , eukaryotic translation initiation factor 4 gamma , rna binding protein , biology , microbiology and biotechnology , soar , eukaryotic initiation factor , chemistry , biochemistry , gene , artificial intelligence , computer science
Summary The translation initiation factor eIF 4E‐binding protein‐mediated regulation of protein translation by interfering with assembly of mRNA cap‐binding complex eIF 4F 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 eIF 4F in plant cells. Here, we report that the two isoforms of Arabidopsis eIF 4G, eIF iso4G1 and eIF iso4G2, interact with a cytoplasmic–nuclear dual‐localized pentatricopeptide repeat protein SOAR 1 to regulate abscisic acid (ABA) signaling. SOAR 1 inhibits interactions of eIF iso4E, eIF 4Es, eIF 4A1, eIF 4B2 and poly(A)‐binding protein PAB 6 with eIF iso4G1 and eIF iso4G2, thereby inhibiting eIF iso4F/mixed eIF 4F assembly and repressing translation initiation. SOAR 1 binds mRNA of a key ABA ‐responsive gene ABI 5 and cooperates with eIF iso4G1/2 to repress translation of ABI 5 . The binding of SOAR 1 to ABI 5 mRNA is likely to inhibit the interaction of SOAR 1 with eIF iso4G1/2, 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.