An RNA-binding Respiratory Component Mediates Import of Type II tRNAs into Leishmania Mitochondria
IR@IICB: CSIR-Indian Institute of Chemical Biology, Kolkata
View Archive Info| Field | Value | |
| Title |
An RNA-binding Respiratory Component Mediates Import
of Type II tRNAs into Leishmania Mitochondria
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| Creator |
Chatterjee, Saibal
Home, Pratik Mukherjee, Saikat Mahata, Bidesh Goswami, Srikanta Dhar, Gunjan Adhya, Samit |
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| Subject |
Molecular & Human Genetics
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| Description |
Transport of tRNAs across the inner mitochondrial membrane
of the kinetoplastid protozoon Leishmania requires interactions with specific binding proteins (receptors) in a multi-subunit complex. The allosteric model of import regulation proposes cooperative and antagonistic interactions between two or more receptors with binding specificities for distinct tRNA families (types I and II,
respectively). To identify the type II receptor, the gene encoding RIC8A, a subunit of the complex, was cloned. The C-terminal region of RIC8A is homologous to subunit 6b of ubiquinol cytochrome c reductase (respiratory complex III), while the N-terminal region has intrinsic affinity for type II, but not for type I, mtRNAs. RIC8A is shared by the import complex and complex III, indicating its bi-functionality, but is assembled differently in the
two complexes. Knockdown of RIC8A in Leishmania lowered
the mitochondrial content of type II tRNAs but raised that of type I tRNAs, with downstream effects on mitochondrial translation and respiration, and cell death. In RIC8A knockdown cells, a subcomplex was formed that interacted with type I tRNA, but the negative regulation by type II tRNA was lost. Mitochondrial extracts from these cells were defective for type II, but not type I, import; import and regulation were restored by purified RIC8A. These results provide evidence for the relevance of allosteric regulation in vivo and indicate that acquisition of new tRNA-binding domains by ancient respiratory components have played a key role in the evolution of mitochondrial tRNA import.
Mitochondria from
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| Date |
2006
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| Type |
Article
PeerReviewed |
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| Format |
application/pdf
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| Identifier |
http://www.eprints.iicb.res.in/481/1/JOURNAL_OF_BIOLOGICAL_CHEMISTRY%2C_281(_35)%2C_25270%2D25277_[43].pdf
Chatterjee, Saibal and Home, Pratik and Mukherjee, Saikat and Mahata, Bidesh and Goswami, Srikanta and Dhar, Gunjan and Adhya, Samit (2006) An RNA-binding Respiratory Component Mediates Import of Type II tRNAs into Leishmania Mitochondria. The Journal of Biological Chemistry, 281 (35). pp. 25270-25277. |
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| Relation |
htpp://dx.doi.org/10.1074/jbc.M604126200
http://www.eprints.iicb.res.in/481/ |
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