title: Phosphoglycerylethanolamine posttranslational modification of plant eukaryotic elongation factor 1alpha.
abstract: Eukaryotic elongation factor 1alpha (eEF-1A) is a multifunctional protein. There are three known posttranslational modifications of eEF-1A that could potentially affect its function. Except for phosphorylation, the other posttranslational modifications have not been demonstrated in plants. Using matrix-assisted laser desorption/ionization-mass spectrometry and peptide mass mapping, we show that carrot (Daucus carota L.) eEF-1A contains a phosphoglycerylethanolamine (PGE) posttranslational modification. eEF-1A was the only protein labeled with [14C]ethanolamine in carrot cells and was the predominant ethanolamine-labeled protein in Arabidopsis seedlings and tobacco (Nicotiana tabacum L.) cell cultures. In vivo-labeling studies using [3H]glycerol, [32P]Pi, [14C]myristic acid, and [14C]linoleic acid indicated that the entire phospholipid phosphatidylethanolamine is covalently attached to the protein. The PGE lipid modification did not affect the partitioning of eEF-1A in Triton X-114 or its actin-binding activity in in vitro assays. Our in vitro data indicate that this newly characterized posttranslational modification alone does not affect the function of eEF-1A. Therefore, the PGE lipid modification may work in combination with other posttranslational modifications to affect the distribution and the function of eEF-1A within the cell.
authors.affiliation: Botany Department, North Carolina State University, Raleigh, North Carolina 27695-7612, USA. wendy_boss@ncsu.edu
authors.forename: W D
authors.initials: WD
authors.lastname: Ransom
authors.forename: P C
authors.initials: PC
authors.lastname: Lao
authors.forename: D A
authors.initials: DA
authors.lastname: Gage
authors.forename: W F
authors.initials: WF
authors.lastname: Boss
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D002250:Carbon Radioisotopes; D017124:Conserved Sequence; D018552:Daucus carota / Q000737:chemistry / Q000378:metabolism*; D019856:Ethanolamine / Q000378:metabolism; D008969:Molecular Sequence Data; D017830:Octoxynol; D020648:Peptide Elongation Factor 1; D010445:Peptide Elongation Factors / Q000737:chemistry / Q000378:metabolism*; D010714:Phosphatidylethanolamines / Q000378:metabolism*; D010940:Plant Proteins / Q000737:chemistry / Q000378:metabolism; D011092:Polyethylene Glycols; D011499:Protein Processing, Post-Translational; D017386:Sequence Homology, Amino Acid
chemical_list: D002250:Carbon Radioisotopes; D020648:Peptide Elongation Factor 1; D010445:Peptide Elongation Factors; D010714:Phosphatidylethanolamines; D010940:Plant Proteins; C002449:glycerophosphoethanolamine; D011092:Polyethylene Glycols; D019856:Ethanolamine; D017830:Octoxynol; C010615:Nonidet P-40