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Updated: Jul 13, 2026

Measurement of Protein Import Capacity of Skeletal Muscle Mitochondria
Published on: January 7, 2022
tRNA import into yeast mitochondria is regulated by the ubiquitin-proteasome system
Irina Brandina1, Alexandre Smirnov, Olga Kolesnikova
1Unité Mixte de Recherche 7156 GMGM, Department of Molecular and Cellular Genetics, Centre National de la Recherche Scientifique-ULP, 21 Rue René Descartes, Strasbourg 67084, France.
Abstract:
In Saccharomyces cerevisiae, one of two cytosolic lysine-tRNAs is partially imported into mitochondria. We demonstrate that three components of the ubiquitin/26S proteasome system (UPS), Rpn13p, Rpn8p and Doa1p interact with the imported tRNA and with the essential factor of its mitochondrial targeting, pre-Msk1p. Genetic and biochemical assays demonstrate that UPS plays a dual regulatory role, since the overall inhibition of cellular proteasome activity reduces tRNA import, while specific depletion of Rpn13p or Doa1p increases it. This result suggests a functional link between UPS and tRNA mitochondrial import in yeast and indicates on the existence of negative and positive import regulators.
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