tRNA import into yeast mitochondria is regulated by the ubiquitin-proteasome system.
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.
Brandina
Irina
I
Unité 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.
Smirnov
Alexandre
A
Kolesnikova
Olga
O
Entelis
Nina
N
Krasheninnikov
Igor A
IA
Martin
Robert P
RP
Tarassov
Ivan
I
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism*; D008954:Models, Biological; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism*; D011485:Protein Binding; D011498:Protein Precursors / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D034443:RNA Transport; D012331:RNA, Fungal / Q000378:metabolism*; D012343:RNA, Transfer / Q000378:metabolism*; D038744:Ribosomal Protein S6 Kinases, 90-kDa / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000201:enzymology / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism; D025801:Ubiquitin / Q000378:metabolism*
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; C099944:DOA1 protein, S cerevisiae; D011498:Protein Precursors; D012331:RNA, Fungal; D029701:Saccharomyces cerevisiae Proteins; D025801:Ubiquitin; D012343:RNA, Transfer; D038744:Ribosomal Protein S6 Kinases, 90-kDa; C116919:mitogen and stress-activated protein kinase 1; D046988:Proteasome Endopeptidase Complex; C061553:ATP dependent 26S protease