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Trypanosoma brucei Tim50 is a mitochondrial inner membrane protein translocator, which regulates expression and function of VDAC
Author(s) -
Duncan Melanie R,
Fullerton Marjorie S,
Singha Ujjal K,
Chaudhuri Minu
Publication year - 2012
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.26.1_supplement.988.11
Subject(s) - voltage dependent anion channel , trypanosoma brucei , microbiology and biotechnology , biology , inner membrane , inner mitochondrial membrane , mitochondrion , mitochondrial carrier , transmembrane protein , atp–adp translocase , phosphatase , translocase of the inner membrane , membrane protein , mitochondrial membrane transport protein , biochemistry , bacterial outer membrane , phosphorylation , gene , membrane , receptor , escherichia coli
A homolog of Tim50 was characterized in Trypanosoma brucei , a parasitic protozoan and the causative agent of human African trypanosomiasis. T. brucei Tim50 (TbTim50) possesses an N‐terminal mitochondrial targeting sequence, a transmembrane domain and a C‐terminal phosphatase domain. Unlike other Tim50 proteins, the transmembrane domain is located near the C‐terminus. TbTim50 separates as a 52‐kDa protein on a denaturing gel, which is larger than its predicted molecular size of 47 kDa, suggesting possible post‐translational modification. TbTim50 is localized in the mitochondrial inner membrane and interacts with TbTim17. It is required for the import of N‐terminal presequence‐containing nuclear encoded proteins into the mitochondria. Induction of TbTim50 RNAi decreased mitochondrial membrane potential, without affecting the levels of many mitochondrial proteins, except for VDAC and TbTim17, which were upregulated. Knockdown or overexpression of TbTim50 reduced cell growth. Unlike its fungal counterpart, TbTim50 possesses phosphatase activity. We hypothesize that TbTim50 regulates phosphorylation of certain mitochondrial proteins such as VDAC. Supported by NIH grants SC1GM081146 and 5T32HL007737‐17.