"Ping-pong" interactions between mitochondrial tRNA import receptors within a multiprotein complex

Bhattacharyya, Subhendra Nath ; Chatterjee, Saibal ; Goswami, Srikanta ; Tripathi, Gayatri ; Dey, Sailendra Nath ; Adhya, Samit (2003) "Ping-pong" interactions between mitochondrial tRNA import receptors within a multiprotein complex Molecular and Cellular Biology, 23 (15). pp. 5217-5224. ISSN 0270-7306

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Official URL: http://mcb.asm.org/cgi/content/abstract/23/15/5217

Related URL: http://dx.doi.org/10.1128/MCB.23.15.5217-5224.2003


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, ~640 kDa) from the inner mitochondrial membrane of the kinetoplastid protozoon Leishmania, consisting of ~130-Å particles, was isolated. The complex, when incorporated into phospholipid vesicles, induced specific, ATP- and proton motive force-dependent transfer of Leishmania tRNATyr as well as of oligoribonucleotides containing the import signal YGGYAGAGC. Moreover, allosteric interactions between tRNATyr and tRNAIle 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 tRNAIle to a 21-kDa component of the complex is dependent upon tRNATyr, while binding of tRNATyr to a 45-kDa component is inhibited by tRNAIle. This "ping-pong" mechanism may be an effective means to maintain a balanced tRNA pool for mitochondrial translation.

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Source:Copyright of this article belongs to American Society for Microbiology.
ID Code:12074
Deposited On:10 Nov 2010 04:45
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