Phosphorylation of the alpha-subunit of plant eukaryotic initiation factor 2 prevents its association with polysomes but does not considerably suppress protein synthesis.

Autor: Zhigailov AV; M.A. Aitkhozhin Institute of Molecular Biology and Biochemistry, Science Committee, Ministry of Education and Science, Almaty, 050012, Kazakhstan. Electronic address: andrzhig@gmail.com., Stanbekova GE; M.A. Aitkhozhin Institute of Molecular Biology and Biochemistry, Science Committee, Ministry of Education and Science, Almaty, 050012, Kazakhstan. Electronic address: gulshanst@yahoo.com., Nizkorodova AS; M.A. Aitkhozhin Institute of Molecular Biology and Biochemistry, Science Committee, Ministry of Education and Science, Almaty, 050012, Kazakhstan. Electronic address: anna_niz@mail.ru., Galiakparov NN; M.A. Aitkhozhin Institute of Molecular Biology and Biochemistry, Science Committee, Ministry of Education and Science, Almaty, 050012, Kazakhstan. Electronic address: nurbol.g@mail.ru., Gritsenko DA; Institute of Plant Biology and Biotechnology, Science Committee, Ministry of Education and Science, Almaty, 050040, Kazakhstan. Electronic address: d.kopytina@gmail.com., Polimbetova NS; M.A. Aitkhozhin Institute of Molecular Biology and Biochemistry, Science Committee, Ministry of Education and Science, Almaty, 050012, Kazakhstan. Electronic address: nspoli@mail.ru., Halford NG; Plant Sciences Department, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, United Kingdom. Electronic address: nigel.halford@rothamsted.ac.uk., Iskakov BK; M.A. Aitkhozhin Institute of Molecular Biology and Biochemistry, Science Committee, Ministry of Education and Science, Almaty, 050012, Kazakhstan. Electronic address: bulat.iskakov@mail.ru.
Jazyk: angličtina
Zdroj: Plant science : an international journal of experimental plant biology [Plant Sci] 2022 Apr; Vol. 317, pp. 111190. Date of Electronic Publication: 2022 Jan 19.
DOI: 10.1016/j.plantsci.2022.111190
Abstrakt: Phosphorylation of the α-subunit of eukaryotic initiation factor 2 (eIF2α) and subsequent inhibition of protein synthesis is a major survival response to different stresses in animal and yeast cells. However, the role of this regulatory mechanism in plants is not unambiguously established to date. Here we describe a slight reduction of polysome abundance in Nicotiana benthamiana after the transient expression of a cDNA, AteIF2α(S56D), encoding a phosphomimetic form of Arabidopsis thaliana eIF2α. In contrast, the expression of a cDNA, AteIF2α(S56A), that encodes a non-phosphorylatable form of AteIF2α caused slightly elevated polysome formation compared to the control. Recombinant AteIF2α(S56A) was detected in association with 40S ribosomal subunit-containing complexes and also in the polysomal fraction, while recombinant AteIF2α(S56D) was detected mainly in complex with 40S subunits. Intentional phosphorylation of TaeIF2α induced by L-histidinol in a wheat germ (Triticum aestivum) cell-free extract did not reduce the abundance of polysomes. Interestingly, the phosphorylated TaeIF2(αP) was not detected in the polysomal fraction, similar to AteIF2α(S56D) in the in vivo experiment. Using mRNAs with a 'Strepto-tag' in the 3' untranslated region, the 48S pre-initiation complexes isolated from histidinol-treated wheat germ extracts were shown to contain phosphorylated TaeIF2(αP). Thus, the phosphorylation of plant eIF2 does not greatly affect its ability to participate in the initiation of mRNA translation, in contrast to animals and yeast, in which eIF2α phosphorylation results in profound suppression of protein synthesis.
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Databáze: MEDLINE
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