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Elucidation of the mechanism for TAO import in T.brucei mitochondria
Author(s) -
Hamilton VaNae Nierra,
Singha Ujjal,
Sharma Shvetank,
Chaudhuri Minu
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.687.2
Subject(s) - mitochondrion , mutant , alternative oxidase , biochemistry , biology , inner membrane , microbiology and biotechnology , amino acid , inner mitochondrial membrane , gene
TAO is the only terminal oxidase in the mitochondria of the bloodstream form of T.brucei . It is a nuclear encoded protein that needs to be imported in mitochondria to be functional. TAO possesses a predicted N‐terminal mitochondrial targeting sequence (MTS). Unlike other MTS containing proteins TAO does not need mitochondrial membrane potential (ψ) for its import in mitochondria of the bloodstream (BS) form but depends on ψ in the procyclic (PS) form of the parasite. To understand the import mechanisms of TAO in the two developmental forms, N‐terminal deletion mutants of this protein were generated. In vitro import of radiolabelled wild type and mutant TAO proteins into mitochondria from BS and PS forms has shown that deletion of the first ten amino acids did not affect the import of TAO in mitochondria from either form, whereas deletion of the first twenty amino acids inhibited import in mitochondria of the PS form only. Unlike the full‐length protein, the first ten amino acid deletion mutant of TAO depends on membrane potential for import in mitochondria of the BS form. These results suggest that length of and basic residues within the MTS of TAO play important roles in requirement of ψ during import. This project is supported by NIH Grants 1SC1GM081146 and 1F31 AI083011‐01.