New Protein Critical for Mitochondria Discovered
ScienceDaily (Nov. 3, 2010) — Researchers in Spain have discovered a new protein in the fly Drosophila melanogaster (fruit fly) that is crucial for mitochondria. The removal of SLIMP in these flies leads to aberrant mitochondria and loss of metabolic capacity, thus causing death.
The study -- whose first author is Tanit Guitart, a PhD student in the lab of Lluís Ribas de Pouplana, ICREA professor at the Institute for Research in Biomedicine (IRB Barcelona) -- appears in the December issue of the Journal of Biological Chemistry, which is already available online.
Result of animal evolution
The SLIMP protein derives from a seryl-tRNA synthetase, universal enzymes that are crucial for the synthesis of new proteins. However, SLIMP has lost its original function and performs a different biological role, which remains to be determined. The researchers studied its possible implication in the regulation of mitochondrial division and the interaction with nucleic acids (DNA, RNA).
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A new aminoacyl-tRNA synthetase-like protein in insecta with an essential mitochondrial function
Tanit Guitart1, Teresa Leon Bernardo1, Jessica Segalés1, Thomas Stratmann2, Jordi Bernués3 and Lluís Ribas de Pouplana4,*
-Author Affiliations
1 IRB, Spain;
2 University of Barcelona, Spain;
3 IRB and IBMB-CSIC, Spain;
4 IRB and ICREA, Spain
* Corresponding author; email: lluis.ribas@irbbarcelona.org
Abstract
Aminoacyl-tRNA synthetases (ARS) are modular enzymes that aminoacylate transfer RNAs (tRNA) for their use by the ribosome during protein synthesis. ARS are essential and universal components of the genetic code that were almost completely established before the appearance of the last common ancestor of all living species. This long evolutionary history explains the growing number of functions being discovered for ARS, and for ARS homologues, beyond their canonical role in gene translation. Here we present a previously uncharacterized paralogue of seryl-tRNA synthetase named SLIMP (seryl-tRNA synthetase-like insect mitochondrial protein). SLIMP is the result of a duplication of a mitochondrial SRS gene that took place in early metazoans and was fixed in Insecta. Here we show that SLIMP is localized in the mitochondria, where it carries out an essential function that is unrelated to the aminoacylation of tRNA. The knock-down of SLIMP by RNA interference (RNAi) causes a decrease in respiration capacity and an increase in mitochondrial mass in the form of aberrant mitochondria.
Aminoacyl tRNA synthetase, Drosophila metabolism, Mitochondria, Oxidative stress, Respiration
Received July 28, 2010.
Accepted September 24, 2010.
Copyright © 2010, The American Society for Biochemistry and Molecular Biology
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