Role of an RNA-binding protein in import of tRNA into Leishmania mitochondria

Adhya, Samit ; Ghosh, Trina ; Das, Anish ; Bera, Saphal Kanti ; Mahapatra, Sridam (1997) Role of an RNA-binding protein in import of tRNA into Leishmania mitochondria Journal of Biological Chemistry, 272 (34). pp. 21396-21402. ISSN 0021-9258

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Nuclear-encoded cytoplasmic tRNAs are imported into the mitochondria of kinetoplastid protozoa by an unknown mechanism. In a Leishmania in organello system, ATP-dependent import of a cloned, unspliced tRNATyr(GUA) transcript was demonstrated by protection from ribonuclease, whereas import of a tRNAGln(CUG) transcript was much less efficient. Specific binding of tRNATyr to two mitochondrial surface proteins of 15 and 22 kilodaltons was observed. Tubulin antisense-binding protein (TAB), the 15-kilodaton species, was purified to apparent homogeneity by RNA affinity chromatography. TAB forms stable complexes with the D stem-loop region of tRNATyr. Immunocytochemical and cell fractionation experiments, combined with limited proteolysis, suggested the association of TAB with the outer mitochondrial membrane. Importantly, anti-TAB antibody specifically inhibited binding as well as import of tRNATyr and of a synthetic structural homolog. These results support the role of TAB as a membrane-bound receptor or carrier for RNA import into Leishmania mitochondria.

Item Type:Article
Source:Copyright of this article belongs to American Society for Biochemistry and Molecular Biology.
ID Code:12061
Deposited On:09 Nov 2010 11:45
Last Modified:16 May 2016 21:27

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