Two proteomic methodologies for defining N-termini of mature human mitochondrial aminoacyl-tRNA synthetases.
Fiche publication
Date publication
janvier 2017
Journal
Methods (San Diego, Calif.)
Auteurs
Membres identifiés du Cancéropôle Est :
Dr CARAPITO Christine
Tous les auteurs :
Carapito C, Kuhn L, Karim L, Rompais M, Rabilloud T, Schwenzer H, Sissler M
Lien Pubmed
Résumé
Human mitochondrial aminoacyl-tRNA synthetases (mt-aaRSs) are encoded in the nucleus, synthesized in the cytosol and targeted for importation into mitochondria by a N-terminal mitochondrial targeting sequence. This targeting sequence is presumably cleaved upon entry into the mitochondria, following a process still not fully deciphered in human, despite essential roles for the mitochondrial biogenesis. Maturation processes are indeed essential both for the release of a functional enzyme and to route correctly the protein within mitochondria. The absence of consensus sequences for cleavage sites and the discovery of possible multiple proteolytic steps render predictions of N-termini difficult. Further, the knowledge of the cleavages is key for the design of protein constructions compatible with efficient production in bacterial strains. Finally, full comprehension becomes essential because a growing number of mutations are found in genes coding for mt-aaRS. In the present study, we take advantage of proteomic methodological developments and identified, in mitochondria, three N-termini for the human mitochondrial aspartyl-tRNA synthetase. This first description of the co-existence of different forms opens new perspectives in the biological understanding of this enzyme. Those methods are extended to the whole set of human mt-aaRSs and methodological advice are provided for further investigations.
Mots clés
Amino Acid Sequence, Amino Acyl-tRNA Synthetases, classification, Cell Fractionation, methods, Cell Line, Tumor, Cell Nucleus, enzymology, Cytosol, chemistry, HEK293 Cells, Humans, Mitochondria, enzymology, Monocytes, cytology, Peptide Fragments, analysis, Protein Biosynthesis, Protein Precursors, classification, Protein Sorting Signals, Protein Transport, Proteomics, instrumentation
Référence
Methods. 2017 Jan 15;113:111-119