“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.
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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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Binding interactions between yeast tRNA ligase and a precursor transfer ribonucleic acid containing two photoreactive uridine analogues
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The D arm of tRNATyr is necessary and sufficient for import into Leishmania mitochondria in vitro
TL;DR: The observation that the imported:bound ratio of the D arm minihelix is higher than that of the entire molecule suggests that the post-binding translocation step is constrained in terms of size or structural flexibility.
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Selective import of nuclear-encoded tRNAs into mitochondria of the protozoan Leishmania tarentolae
TL;DR: The data showing that tRNAs derived from the clustered genomic tRNA genes are invariably imported into mitochondria, while tRNA from the solitary gene is not is presented, ruling out the possibility that t RNAs found in the trypanosomatid mitochondrion are the products of the U-addition type 'RNA editing' of maxicircle DNA.
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Role of an RNA-binding Protein in Import of tRNA into Leishmania Mitochondria
TL;DR: The role of TAB as a membrane-bound receptor or carrier for RNA import into Leishmania mitochondria is supported, and anti-TAB antibody specifically inhibited binding as well as import of tRNATyr and of a synthetic structural homolog.
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Mitochondrial RNA import in Leishmania tropica: aptamers homologous to multiple tRNA domains that interact cooperatively or antagonistically at the inner membrane.
TL;DR: A large number of cytoplasmic tRNAs are imported into the kinetoplast-mitochondrion of Leishmania by a receptor-mediated process, resulting in rapid selection of several import aptamers containing sequence motifs present in the anticodon arm, the D arms, the V-T region, and acceptor stem of known tRNAAs, confirming or suggesting the presence of import signals in these domains.