Echevarría 2014 Biochem J

Echevarría L, Clemente P, Hernández Sierra R, Gallardo ME, Fernández-Moreno MA, Garesse R (2014) Mammalian GatCAB is essential for mitochondrial translation 1 Glutamyl-tRNAGln amidotransferase is essential for mammalian mitochondrial translation in vivo. Biochem J 460:91-101.

» PMID:24579914

Echevarria L, Clemente P, Hernandez Sierra R, Gallardo ME, Fernandez-Moreno MA, Garesse R (2014) Biochem J

Abstract: 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 glutamyl-tRNAGln amidotransferase (GatCAB), which are able to catalyze the formation of Gln-tRNAGln in vitro. Here we demonstrate that mgatA 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 radical oxygen species (ROS) levels. Mass spectrometry 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 the mitochondrial protein synthesis in mammals.

• O2k-Network Lab: ES Madrid Garesse R

Labels: MiParea: Respiration, mtDNA;mt-genetics 

Organism: Human, Mouse  Tissue;cell: Other cell lines, HEK, HeLa  Preparation: Intact cells 

Coupling state: LEAK, ET  Pathway: N  HRR: Oxygraph-2k