Protein translocase of mitochondrial inner membrane in Trypanosoma brucei

Ujjal K. Singha, Va Nae Hamilton, Melanie R. Duncan, Ebony Weems, Manish Tripathi, Minu Chaudhuri

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

Translocases of mitochondrial inner membrane (TIMs) are multiprotein complexes. The only Tim component so far characterized in kinetoplastid parasites such as Trypanosoma brucei is Tim17 (TbTim17), which is essential for cell survival and mitochondrial protein import. Here, we report that TbTim17 is present in a protein complex of about 1,100 kDa, which is much larger than the TIM complexes found in fungi and mammals. Depletion of TbTim17 in T. brucei impairs the mitochondrial import of cytochrome oxidase subunit IV, an N-terminal signal-containing protein. Pretreatment of isolated mitoplasts with the anti-TbTim17 antibody inhibited import of cytochrome oxidase subunit IV, indicating a direct involvement of the TbTim17 in the import process. Purification of the TbTim17-containing protein complex from the mitochondrial membrane of T. brucei by tandem affinity chromatography revealed that TbTim17 associates with seven unique as well as a few known T. brucei mitochondrial proteins. Depletion of three of these novel proteins, i.e. TbTim47, TbTim54, and TbTim62, significantly decreased mitochondrial protein import in vitro. In vivo targeting of a newly synthesized mitochondrial matrix protein, MRP2, was also inhibited due to depletion of TbTim17, TbTim54, and TbTim62. Co-precipitation analysis confirmed the interaction of TbTim54 and TbTim62 with TbTim17 in vivo. Overall, our data reveal that TbTim17, the single homolog of Tim17/22/23 family proteins, is present in a unique TIM complex consisting of novel proteins in T. brucei and is critical for mitochondrial protein import.

Original languageEnglish (US)
Pages (from-to)14480-14493
Number of pages14
JournalJournal of Biological Chemistry
Volume287
Issue number18
DOIs
StatePublished - Apr 27 2012

Fingerprint

Trypanosoma brucei brucei
Mitochondrial Membranes
Membranes
Mitochondrial Proteins
Proteins
Electron Transport Complex IV
Affinity chromatography
Multiprotein Complexes
Mammals
Coprecipitation
Fungi
Purification
Cells
Antibodies
Affinity Chromatography

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Cite this

Singha, U. K., Hamilton, V. N., Duncan, M. R., Weems, E., Tripathi, M., & Chaudhuri, M. (2012). Protein translocase of mitochondrial inner membrane in Trypanosoma brucei. Journal of Biological Chemistry, 287(18), 14480-14493. https://doi.org/10.1074/jbc.M111.322925

Protein translocase of mitochondrial inner membrane in Trypanosoma brucei. / Singha, Ujjal K.; Hamilton, Va Nae; Duncan, Melanie R.; Weems, Ebony; Tripathi, Manish; Chaudhuri, Minu.

In: Journal of Biological Chemistry, Vol. 287, No. 18, 27.04.2012, p. 14480-14493.

Research output: Contribution to journalArticle

Singha, UK, Hamilton, VN, Duncan, MR, Weems, E, Tripathi, M & Chaudhuri, M 2012, 'Protein translocase of mitochondrial inner membrane in Trypanosoma brucei', Journal of Biological Chemistry, vol. 287, no. 18, pp. 14480-14493. https://doi.org/10.1074/jbc.M111.322925
Singha, Ujjal K. ; Hamilton, Va Nae ; Duncan, Melanie R. ; Weems, Ebony ; Tripathi, Manish ; Chaudhuri, Minu. / Protein translocase of mitochondrial inner membrane in Trypanosoma brucei. In: Journal of Biological Chemistry. 2012 ; Vol. 287, No. 18. pp. 14480-14493.
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