title: eIF4A RNA Helicase Associates with Cyclin-Dependent Protein Kinase A in Proliferating Cells and Is Modulated by Phosphorylation.
abstract: 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 5'-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.
authors.affiliation: Department of Cell and Developmental Biology, John Innes Centre, Norwich NR4 7UH, United Kingdom (M.S.B., O.P., V.M.);Institute of Biological, Environmental, and Rural Sciences, Aberystwyth University, Gogerddan Campus, Aberystwyth SY23 3EE, United Kingdom (C.N., F.M.K.C., K.V., J.H.D.);Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Science, Hangzhou City, Zhejiang Province 310021, China (T.Z.);Aristotle University of Thessaloniki, Faculty of Science, School of Biology, Department of Botany, 54124 Thessaloniki, Greece (K.V.); andDepartment of Molecular Biosciences and Institute for Cell and Molecular Biology, University of Texas, Austin, Texas 78712 (L.K.M., K.S.B.).
authors.forename: Maxwell S
authors.initials: MS
authors.lastname: Bush
authors.affiliation: Department of Cell and Developmental Biology, John Innes Centre, Norwich NR4 7UH, United Kingdom (M.S.B., O.P., V.M.);Institute of Biological, Environmental, and Rural Sciences, Aberystwyth University, Gogerddan Campus, Aberystwyth SY23 3EE, United Kingdom (C.N., F.M.K.C., K.V., J.H.D.);Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Science, Hangzhou City, Zhejiang Province 310021, China (T.Z.);Aristotle University of Thessaloniki, Faculty of Science, School of Biology, Department of Botany, 54124 Thessaloniki, Greece (K.V.); andDepartment of Molecular Biosciences and Institute for Cell and Molecular Biology, University of Texas, Austin, Texas 78712 (L.K.M., K.S.B.).
authors.forename: Olivier
authors.initials: O
authors.lastname: Pierrat
authors.affiliation: Department of Cell and Developmental Biology, John Innes Centre, Norwich NR4 7UH, United Kingdom (M.S.B., O.P., V.M.);Institute of Biological, Environmental, and Rural Sciences, Aberystwyth University, Gogerddan Campus, Aberystwyth SY23 3EE, United Kingdom (C.N., F.M.K.C., K.V., J.H.D.);Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Science, Hangzhou City, Zhejiang Province 310021, China (T.Z.);Aristotle University of Thessaloniki, Faculty of Science, School of Biology, Department of Botany, 54124 Thessaloniki, Greece (K.V.); andDepartment of Molecular Biosciences and Institute for Cell and Molecular Biology, University of Texas, Austin, Texas 78712 (L.K.M., K.S.B.).
authors.forename: Candida
authors.initials: C
authors.lastname: Nibau
authors.affiliation: Department of Cell and Developmental Biology, John Innes Centre, Norwich NR4 7UH, United Kingdom (M.S.B., O.P., V.M.);Institute of Biological, Environmental, and Rural Sciences, Aberystwyth University, Gogerddan Campus, Aberystwyth SY23 3EE, United Kingdom (C.N., F.M.K.C., K.V., J.H.D.);Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Science, Hangzhou City, Zhejiang Province 310021, China (T.Z.);Aristotle University of Thessaloniki, Faculty of Science, School of Biology, Department of Botany, 54124 Thessaloniki, Greece (K.V.); andDepartment of Molecular Biosciences and Institute for Cell and Molecular Biology, University of Texas, Austin, Texas 78712 (L.K.M., K.S.B.).
authors.forename: Veronika
authors.initials: V
authors.lastname: Mikitova
authors.affiliation: Department of Cell and Developmental Biology, John Innes Centre, Norwich NR4 7UH, United Kingdom (M.S.B., O.P., V.M.);Institute of Biological, Environmental, and Rural Sciences, Aberystwyth University, Gogerddan Campus, Aberystwyth SY23 3EE, United Kingdom (C.N., F.M.K.C., K.V., J.H.D.);Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Science, Hangzhou City, Zhejiang Province 310021, China (T.Z.);Aristotle University of Thessaloniki, Faculty of Science, School of Biology, Department of Botany, 54124 Thessaloniki, Greece (K.V.); andDepartment of Molecular Biosciences and Institute for Cell and Molecular Biology, University of Texas, Austin, Texas 78712 (L.K.M., K.S.B.).
authors.forename: Tao
authors.initials: T
authors.lastname: Zheng
authors.affiliation: Department of Cell and Developmental Biology, John Innes Centre, Norwich NR4 7UH, United Kingdom (M.S.B., O.P., V.M.);Institute of Biological, Environmental, and Rural Sciences, Aberystwyth University, Gogerddan Campus, Aberystwyth SY23 3EE, United Kingdom (C.N., F.M.K.C., K.V., J.H.D.);Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Science, Hangzhou City, Zhejiang Province 310021, China (T.Z.);Aristotle University of Thessaloniki, Faculty of Science, School of Biology, Department of Botany, 54124 Thessaloniki, Greece (K.V.); andDepartment of Molecular Biosciences and Institute for Cell and Molecular Biology, University of Texas, Austin, Texas 78712 (L.K.M., K.S.B.).
authors.forename: Fiona M K
authors.initials: FM
authors.lastname: Corke
authors.affiliation: Department of Cell and Developmental Biology, John Innes Centre, Norwich NR4 7UH, United Kingdom (M.S.B., O.P., V.M.);Institute of Biological, Environmental, and Rural Sciences, Aberystwyth University, Gogerddan Campus, Aberystwyth SY23 3EE, United Kingdom (C.N., F.M.K.C., K.V., J.H.D.);Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Science, Hangzhou City, Zhejiang Province 310021, China (T.Z.);Aristotle University of Thessaloniki, Faculty of Science, School of Biology, Department of Botany, 54124 Thessaloniki, Greece (K.V.); andDepartment of Molecular Biosciences and Institute for Cell and Molecular Biology, University of Texas, Austin, Texas 78712 (L.K.M., K.S.B.).
authors.forename: Konstantinos
authors.identifier: 0000-0003-1755-1645
authors.initials: K
authors.lastname: Vlachonasios
authors.affiliation: Department of Cell and Developmental Biology, John Innes Centre, Norwich NR4 7UH, United Kingdom (M.S.B., O.P., V.M.);Institute of Biological, Environmental, and Rural Sciences, Aberystwyth University, Gogerddan Campus, Aberystwyth SY23 3EE, United Kingdom (C.N., F.M.K.C., K.V., J.H.D.);Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Science, Hangzhou City, Zhejiang Province 310021, China (T.Z.);Aristotle University of Thessaloniki, Faculty of Science, School of Biology, Department of Botany, 54124 Thessaloniki, Greece (K.V.); andDepartment of Molecular Biosciences and Institute for Cell and Molecular Biology, University of Texas, Austin, Texas 78712 (L.K.M., K.S.B.).
authors.forename: Laura K
authors.initials: LK
authors.lastname: Mayberry
authors.affiliation: Department of Cell and Developmental Biology, John Innes Centre, Norwich NR4 7UH, United Kingdom (M.S.B., O.P., V.M.);Institute of Biological, Environmental, and Rural Sciences, Aberystwyth University, Gogerddan Campus, Aberystwyth SY23 3EE, United Kingdom (C.N., F.M.K.C., K.V., J.H.D.);Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Science, Hangzhou City, Zhejiang Province 310021, China (T.Z.);Aristotle University of Thessaloniki, Faculty of Science, School of Biology, Department of Botany, 54124 Thessaloniki, Greece (K.V.); andDepartment of Molecular Biosciences and Institute for Cell and Molecular Biology, University of Texas, Austin, Texas 78712 (L.K.M., K.S.B.) kbrowning@cm.utexas.edu john.doonan@aber.ac.uk.
authors.forename: Karen S
authors.initials: KS
authors.lastname: Browning
authors.affiliation: Department of Cell and Developmental Biology, John Innes Centre, Norwich NR4 7UH, United Kingdom (M.S.B., O.P., V.M.);Institute of Biological, Environmental, and Rural Sciences, Aberystwyth University, Gogerddan Campus, Aberystwyth SY23 3EE, United Kingdom (C.N., F.M.K.C., K.V., J.H.D.);Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Science, Hangzhou City, Zhejiang Province 310021, China (T.Z.);Aristotle University of Thessaloniki, Faculty of Science, School of Biology, Department of Botany, 54124 Thessaloniki, Greece (K.V.); andDepartment of Molecular Biosciences and Institute for Cell and Molecular Biology, University of Texas, Austin, Texas 78712 (L.K.M., K.S.B.) kbrowning@cm.utexas.edu john.doonan@aber.ac.uk.
authors.forename: John H
authors.identifier: 0000-0001-6027-1919
authors.initials: JH
authors.lastname: Doonan
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000201:enzymology / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D001665:Binding Sites / Q000235:genetics; D002460:Cell Line; D049109:Cell Proliferation / Q000235:genetics*; D018844:Cyclin-Dependent Kinases / Q000235:genetics* / Q000378:metabolism; D039601:Eukaryotic Initiation Factor-4A / Q000235:genetics* / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D009154:Mutation; D056771:Ovule / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D018517:Plant Roots / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D011485:Protein Binding; D020365:RNA Helicases / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013912:Threonine / Q000235:genetics / Q000378:metabolism; D020798:Two-Hybrid System Techniques
chemical_list: D029681:Arabidopsis Proteins; D013912:Threonine; D018844:Cyclin-Dependent Kinases; D039601:Eukaryotic Initiation Factor-4A; D020365:RNA Helicases