eIF4A RNA Helicase Associates with Cyclin-Dependent Protein Kinase A in Proliferating Cells and Is Modulated by Phosphorylation(1[OPEN])

文献类型： 外文期刊

第一作者： Bush, Maxwell S.

作者： Bush, Maxwell S.;Pierrat, Olivier;Mikitova, Veronika;Nibau, Candida;Corke, Fiona M. K.;Browning, Karen S.;Doonan, John H.;Zheng, Tao;Vlachonasios, Konstantinos;Mayberry, Laura K.;Browning, Karen S.;Mayberry, Laura K.;Browning, Karen S.;Pierrat, Olivier;Mikitova, Veronika

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期刊名称：PLANT PHYSIOLOGY （ 影响因子：8.34； 五年影响因子：8.972 ）

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收录情况： SCI

摘要： Eukaryotic initiation factor 4A (eIF4A) is a highly conserved RNA-stimulated ATPase and helicase involved in the initiation of messenger RNA translation. Previously, we found that eIF4A interacts with cyclin-dependent kinase A (CDKA), the plant ortholog of mammalian CDK1. Here, we show that this interaction occurs only in proliferating cells where the two proteins coassociate with 59-cap-binding protein complexes, eIF4F or the plant-specific eIFiso4F. CDKA phosphorylates eIF4A on a conserved threonine residue (threonine-164) within the RNA-binding motif 1b TPGR. In vivo, a phospho-null (APGR) variant of the Arabidopsis (Arabidopsis thaliana) eIF4A1 protein retains the ability to functionally complement a mutant (eif4a1) plant line lacking eIF4A1, whereas a phosphomimetic (EPGR) variant fails to complement. The phospho-null variant (APGR) rescues the slow growth rate of roots and rosettes, together with the ovule-abortion and late-flowering phenotypes. In vitro, wild-type recombinant eIF4A1 and its phospho-null variant both support translation in cell-free wheat germ extracts dependent upon eIF4A, but the phosphomimetic variant does not support translation and also was deficient in ATP hydrolysis and helicase activity. These observations suggest a mechanism whereby CDK phosphorylation has the potential to down-regulate eIF4A activity and thereby affect translation.

分类号： Q945

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