| First Author | Echevarría L | Year | 2014 |
| Journal | Biochem J | Volume | 460 |
| Issue | 1 | Pages | 91-101 |
| PubMed ID | 24579914 | Mgi Jnum | J:212283 |
| Mgi Id | MGI:5578427 | Doi | 10.1042/BJ20131107 |
| Citation | Echevarria L, et al. (2014) Glutamyl-tRNAGln amidotransferase is essential for mammalian mitochondrial translation in vivo. Biochem J 460(1):91-101 |
| abstractText | Translational accuracy depends on the correct formation of aminoacyl-tRNAs, which, in the majority of cases, are produced by specific aminoacyl-tRNA synthetases that ligate each amino acid to its cognate isoaceptor tRNA. Aminoacylation of tRNAGln, however, is performed by various mechanisms in different systems. Since no mitochondrial glutaminyl-tRNA synthetase has been identified to date in mammalian mitochondria, Gln-tRNAGln has to be formed by an indirect mechanism in the organelle. It has been demonstrated that human mitochondria contain a non-discriminating glutamyl-tRNA synthetase and the heterotrimeric enzyme GatCAB (where Gat is glutamyl-tRNAGln amidotransferase), which are able to catalyse the formation of Gln-tRNAGln in vitro. In the present paper we demonstrate that mgatA (mouse GatA) interference in mouse cells produces a strong defect in mitochondrial translation without affecting the stability of the newly synthesized proteins. As a result, interfered cells present an impairment of the oxidative phosphorylation system and a significant increase in ROS (reactive oxygen species) levels. MS analysis of mitochondrial proteins revealed no glutamic acid found in the position of glutamines, strongly suggesting that misaminoacylated Glu-tRNAGln is rejected from the translational apparatus to maintain the fidelity of mitochondrial protein synthesis in mammals. |
