title: Dual targeting of organellar seryl-tRNA synthetase to maize mitochondria and chloroplasts.
abstract: Aminoacyl-tRNA synthetases (AARSs) play a critical role in translation and are thus required in three plant protein-synthesizing compartments: cytosol, mitochondria and plastids. A systematic study had previously shown extensive sharing of organellar AARSs from Arabidopsis thaliana, mostly between mitochondria and chloroplasts. However, distribution of AARSs from monocot species, such as maize, has never been experimentally investigated. Here we demonstrate dual targeting of maize seryl-tRNA synthetase, SerZMo, into both mitochondria and chloroplasts using combination of complementary methods, including in vitro import assay, transient expression analysis of green fluorescent protein (GFP) fusions and immunodetection. We also show that SerZMo dual localization is established by the virtue of an ambiguous targeting peptide. Full-length SerZMo protein fused to GFP is targeted to chloroplast stromules, indicating that SerZMo protein performs its function in plastid stroma. The deletion mutant lacking N-terminal region of the ambiguous SerZMo targeting peptide was neither targeted into mitochondria nor chloroplasts, indicating the importance of this region in both mitochondrial and chloroplastic import.
authors.affiliation: Department of Chemistry, Faculty of Natural Sciences, University of Zagreb, Horvatovac 102a, 10000 Zagreb, Croatia. rokov@chem.pmf.hr
authors.forename: Jasmina
authors.initials: J
authors.lastname: Rokov-Plavec
authors.forename: Morana
authors.initials: M
authors.lastname: Dulic
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Duchêne
authors.forename: Ivana
authors.initials: I
authors.lastname: Weygand-Durasevic
mesh_terms: D000595:Amino Acid Sequence; D002736:Chloroplasts / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D015151:Immunoblotting; D008928:Mitochondria / Q000378:metabolism*; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012714:Serine-tRNA Ligase / Q000235:genetics / Q000378:metabolism*; D003313:Zea mays / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*
chemical_list: D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D012714:Serine-tRNA Ligase