“Ping-Pong” Interactions between Mitochondrial tRNA Import Receptors within a Multiprotein Complex
Subhendra Nath Bhattacharyya,Saibal Chatterjee,Srikanta Goswami,Gayatri Tripathi,Sailendra Nath Dey,Samit Adhya +5 more
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TLDR
By a combination of antibody inhibition, photochemical cross-linking, and immunoprecipitation, it was shown that binding of tRNAIle to a 21-kDa component of the complex is dependent upon tRNATyr, whilebinding of tR NATyr to a 45-KDa component is inhibited by t RNAIle, suggesting this “ping-pong” mechanism may be an effective means to maintain a balanced tRNA pool for mitochondrial translation.Abstract:
The mitochondrial genomes of a wide variety of species contain an insufficient number of functional tRNA genes, and translation of mitochondrial mRNAs is sustained by import of nucleus-encoded tRNAs. In Leishmania, transfer of tRNAs across the inner membrane can be regulated by positive and negative interactions between them. To define the factors involved in such interactions, a large multisubunit complex (molecular mass, approximately 640 kDa) from the inner mitochondrial membrane of the kinetoplastid protozoon Leishmania, consisting of approximately 130-A particles, was isolated. The complex, when incorporated into phospholipid vesicles, induced specific, ATP- and proton motive force-dependent transfer of Leishmania tRNA(Tyr) as well as of oligoribonucleotides containing the import signal YGGYAGAGC. Moreover, allosteric interactions between tRNA(Tyr) and tRNA(Ile) were observed in the RNA import complex-reconstituted system, indicating the presence of primary and secondary tRNA binding sites within the complex. By a combination of antibody inhibition, photochemical cross-linking, and immunoprecipitation, it was shown that binding of tRNA(Ile) to a 21-kDa component of the complex is dependent upon tRNA(Tyr), while binding of tRNA(Tyr) to a 45-kDa component is inhibited by tRNA(Ile). This "ping-pong" mechanism may be an effective means to maintain a balanced tRNA pool for mitochondrial translation.read more
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Nuclear DNA-encoded tRNAs targeted into mitochondria can rescue a mitochondrial DNA mutation associated with the MERRF syndrome in cultured human cells
Olga Kolesnikova,Nina Entelis,Clarisse Jacquin-Becker,Francine Goltzene,Zofia M.A. Chrzanowska-Lightowlers,Robert N. Lightowlers,Robert P. Martin,Ivan Tarassov +7 more
TL;DR: These findings prove for the first time the functionality of imported tRNAs in human mitochondria in vivo and highlight the potential for exploiting the RNA import pathway to treat patients with mtDNA diseases.
Journal ArticleDOI
Import of tRNAs and aminoacyl-tRNA synthetases into mitochondria.
TL;DR: All mitochondrial aminoacyl-tRNA synthetases and many tRNAs are imported from the cytosol into the mitochondria in eukaryotic cells and their origin and their import into the organelle have been studied in evolutionary distinct organisms.
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Recent advances in tRNA mitochondrial import
TL;DR: The characterization of both direct and co-import mechanisms involving distinct protein-import factors is in agreement with a polyphyletic origin of tRNA import.
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The voltage-dependent anion channel, a major component of the tRNA import machinery in plant mitochondria
Thalia Salinas,Anne-Marie Duchêne,Ludovic Delage,Stefan K. Nilsson,Elzbieta Glaser,Marlyse Zaepfel,Laurence Maréchal-Drouard +6 more
TL;DR: These findings identify unexpected components of the tRNA import machinery and suggest that the plant tRNAs import pathway has evolved by recruiting multifunctional proteins.
Journal ArticleDOI
Functional delivery of a cytosolic tRNA into mutant mitochondria of human cells
TL;DR: It is found that the Leishmania RNA import complex (RIC) could enter human cells by a caveolin-1–dependent pathway, where it induced import of endogenous cytosolic tRNAs, including tRNALys, and restored mitochondrial function in a cybrid harboring a mutant mt tRNalys (MT-TK) gene.
References
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Kinetoplastid mitochondria contain functional tRNAs which are encoded in nuclear DNA and also contain small mlnltircJe and maxicircle transcripts of unknown function
TL;DR: Most if not all mitochondrial tRNAs in L. tarentolae are nuclear-encoded and imported into the mitochondrion, suggesting that the KtRNA fraction is free of CtRNA contamination.
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The mitochondrial tRNAs of Trypanosoma brucei are nuclear encoded.
Kathy Hancock,Stephen L. Hajduk +1 more
TL;DR: It is determined that the mitochondrial tRNAs of T. brucei are encoded by nuclear DNA, which implies that RNAs, like proteins, are imported into the mitochondria.
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Mitochondrial tRNA import: are there distinct mechanisms?
TL;DR: These studies show that the import systems of different species exhibit some unique features, suggesting that more than one mechanism might exist to import tRNAs.
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Suppression of Mutations in Mitochondrial DNA by tRNAs Imported from the Cytoplasm
Olga Kolesnikova,Nina S. Entelis,Nina S. Entelis,Hakim Mireau,Thomas D. Fox,Robert P. Martin,Ivan Tarassov +6 more
TL;DR: It is shown that cytoplasmic tRNAs with altered aminoacylation identity can be specifically targeted to the mitochondria and participate in mitochondrial translation and that human mitochondria are able to internalize yeast tRNA derivatives in vitro and that this import requires an essential yeast import factor.
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Import of RNA into Leishmania Mitochondria Occurs through Direct Interaction with Membrane-bound Receptors
Sridam Mahapatra,Samit Adhya +1 more
TL;DR: It was shown that a small, importable RNA, which is structurally homologous to tRNA, binds rapidly, specifically, and with high affinity to the mitochondrial surface in the absence of soluble protein factors to form an import intermediate.