Plant-Specific Preprotein and Amino Acid Transporter Proteins Are Required for tRNA Import into Mitochondria.
Fiche publication
Date publication
décembre 2016
Journal
Plant physiology
Auteurs
Membres identifiés du Cancéropôle Est :
Dr MARÉCHAL-DROUARD Laurence
Tous les auteurs :
Murcha MW, Kubiszewski-Jakubiak S, Teixeira PF, Gügel IL, Kmiec B, Narsai R, Ivanova A, Megel C, Schock A, Kraus S, Berkowitz O, Glaser E, Philippar K, Maréchal-Drouard L, Soll J, Whelan J
Lien Pubmed
Résumé
A variety of eukaryotes, in particular plants, do not contain the required number of tRNAs to support the translation of mitochondria-encoded genes and thus need to import tRNAs from the cytosol. This study identified two Arabidopsis (Arabidopsis thaliana) proteins, Tric1 and Tric2 (for tRNA import component), which on simultaneous inactivation by T-DNA insertion lines displayed a severely delayed and chlorotic growth phenotype and significantly reduced tRNA import capacity into isolated mitochondria. The predicted tRNA-binding domain of Tric1 and Tric2, a sterile-α-motif at the C-terminal end of the protein, was required to restore tRNA uptake ability in mitochondria of complemented plants. The purified predicted tRNA-binding domain binds the T-arm of the tRNA for alanine with conserved lysine residues required for binding. T-DNA inactivation of both Tric proteins further resulted in an increase in the in vitro rate of in organello protein synthesis, which was mediated by a reorganization of the nuclear transcriptome, in particular of genes encoding a variety of proteins required for mitochondrial gene expression at both the transcriptional and translational levels. The characterization of Tric1/2 provides mechanistic insight into the process of tRNA import into mitochondria and supports the theory that the tRNA import pathway resulted from the repurposing of a preexisting protein import apparatus.
Mots clés
Amino Acid Sequence, Amino Acid Transport Systems, metabolism, Arabidopsis, genetics, Arabidopsis Proteins, chemistry, Gene Deletion, Gene Expression Profiling, Gene Expression Regulation, Plant, Mitochondria, metabolism, Mitochondrial Membranes, metabolism, Mitochondrial Proteins, metabolism, Plant Leaves, metabolism, Protein Binding, Protein Biosynthesis, Protein Domains, RNA Transport, RNA, Transfer, chemistry, RNA-Binding Proteins, metabolism, Species Specificity, Transcriptome, genetics
Référence
Plant Physiol.. 2016 Dec;172(4):2471-2490