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Darden C, Donkor JE, Korolkova O, Barozai MYK, Chaudhuri M. Distinct structural motifs are necessary for targeting and import of Tim17 in Trypanosoma brucei mitochondrion. mSphere 2024; 9:e0055823. [PMID: 38193679 PMCID: PMC10871166 DOI: 10.1128/msphere.00558-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 11/28/2023] [Indexed: 01/10/2024] Open
Abstract
Nuclear-encoded mitochondrial proteins are correctly translocated to their proper sub-mitochondrial destination using location-specific mitochondrial targeting signals and via multi-protein import machineries (translocases) in the outer and inner mitochondrial membranes (TOM and TIMs, respectively). However, targeting signals of multi-pass Tims are less defined. Here, we report the characterization of the targeting signals of Trypanosoma brucei Tim17 (TbTim17), an essential component of the most divergent TIM complex. TbTim17 possesses a characteristic secondary structure including four predicted transmembrane (TM) domains in the center with hydrophilic N- and C-termini. After examining mitochondrial localization of various deletion and site-directed mutants of TbTim17 in T. brucei using subcellular fractionation and confocal microscopy, we located at least two internal targeting signals (ITS): (i) within TM1 (31-50 AAs) and (ii) TM4 + loop 3 (120-136 AAs). Both signals are required for proper targeting and integration of TbTim17 in the membrane. Furthermore, a positively charged residue (K122) is critical for mitochondrial localization of TbTim17. This is the first report of characterizing the ITS for a multipass inner membrane protein in a divergent eukaryote, like T. brucei.IMPORTANCEAfrican trypanosomiasis (AT) is a deadly disease in human and domestic animals, caused by the parasitic protozoan Trypanosoma brucei. Therefore, AT is not only a concern for human health but also for economic development in the vast area of sub-Saharan Africa. T. brucei possesses a single mitochondrion per cell that imports hundreds of nuclear-encoded mitochondrial proteins for its functions. T. brucei Tim17 (TbTim17), an essential component of the TbTIM17 complex, is a nuclear-encoded protein; thus, it is necessary to be imported from the cytosol to form the TbTIM17 complex. Here, we demonstrated that the internal targeting signals within the transmembrane 1 (TM1) and TM4 with loop 3, and residue K122 are required collectively for import and integration of TbTim17 in the T. brucei mitochondrion. This information could be utilized to block TbTim17 function and parasite growth.
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Affiliation(s)
- Chauncey Darden
- Department of Biochemistry, Cancer Biology, Neuroscience, and Pharmacology, Meharry Medical College, Nashville, Tennessee, USA
| | - Joseph E. Donkor
- Department of Microbiology, Immunology, and Physiology, Meharry Medical College, Nashville, Tennessee, USA
| | - Olga Korolkova
- The Consolidated Research Instrumentation, Informatics, Statistics, and Learning Integration Suite (CRISALIS), Meharry Medical College, Nashville, Tennessee, USA
| | | | - Minu Chaudhuri
- Department of Microbiology, Immunology, and Physiology, Meharry Medical College, Nashville, Tennessee, USA
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Quiñones LS, Gonzalez FS, Darden C, Khan M, Tripathi A, Smith JT, Davis J, Misra S, Chaudhuri M. Unique Interactions of the Small Translocases of the Mitochondrial Inner Membrane (Tims) in Trypanosoma brucei. Int J Mol Sci 2024; 25:1415. [PMID: 38338692 PMCID: PMC10855554 DOI: 10.3390/ijms25031415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 01/10/2024] [Accepted: 01/19/2024] [Indexed: 02/12/2024] Open
Abstract
The infectious agent for African trypanosomiasis, Trypanosoma brucei, possesses a unique and essential translocase of the mitochondrial inner membrane, known as the TbTIM17 complex. TbTim17 associates with six small TbTims (TbTim9, TbTim10, TbTim11, TbTim12, TbTim13, and TbTim8/13). However, the interaction patterns of these smaller TbTims with each other and TbTim17 are not clear. Through yeast two-hybrid (Y2H) and co-immunoprecipitation analyses, we demonstrate that all six small TbTims interact with each other. Stronger interactions were found among TbTim8/13, TbTim9, and TbTim10. However, TbTim10 shows weaker associations with TbTim13, which has a stronger connection with TbTim17. Each of the small TbTims also interacts strongly with the C-terminal region of TbTim17. RNAi studies indicated that among all small TbTims, TbTim13 is most crucial for maintaining the steady-state levels of the TbTIM17 complex. Further analysis of the small TbTim complexes by size exclusion chromatography revealed that each small TbTim, except for TbTim13, is present in ~70 kDa complexes, possibly existing in heterohexameric forms. In contrast, TbTim13 is primarily present in the larger complex (>800 kDa) and co-fractionates with TbTim17. Altogether, our results demonstrate that, relative to other eukaryotes, the architecture and function of the small TbTim complexes are specific to T. brucei.
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Affiliation(s)
- Linda S. Quiñones
- Department of Microbiology, Immunology, and Physiology, School of Medicine, Meharry Medical College, Nashville, TN 37208, USA; (L.S.Q.); (F.S.G.); (M.K.); (A.T.)
| | - Fidel Soto Gonzalez
- Department of Microbiology, Immunology, and Physiology, School of Medicine, Meharry Medical College, Nashville, TN 37208, USA; (L.S.Q.); (F.S.G.); (M.K.); (A.T.)
| | - Chauncey Darden
- Department of Biochemistry, Cancer Biology, Neuroscience, and Pharmacology, School of Medicine, Meharry Medical College, Nashville, TN 37208, USA; (C.D.); (J.D.)
| | - Muhammad Khan
- Department of Microbiology, Immunology, and Physiology, School of Medicine, Meharry Medical College, Nashville, TN 37208, USA; (L.S.Q.); (F.S.G.); (M.K.); (A.T.)
| | - Anuj Tripathi
- Department of Microbiology, Immunology, and Physiology, School of Medicine, Meharry Medical College, Nashville, TN 37208, USA; (L.S.Q.); (F.S.G.); (M.K.); (A.T.)
| | - Joseph T. Smith
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY 14203, USA;
| | - Jamaine Davis
- Department of Biochemistry, Cancer Biology, Neuroscience, and Pharmacology, School of Medicine, Meharry Medical College, Nashville, TN 37208, USA; (C.D.); (J.D.)
| | - Smita Misra
- Department of Biomedical Science, School of Graduate Studies, Meharry Medical College, Nashville, TN 37208, USA;
| | - Minu Chaudhuri
- Department of Microbiology, Immunology, and Physiology, School of Medicine, Meharry Medical College, Nashville, TN 37208, USA; (L.S.Q.); (F.S.G.); (M.K.); (A.T.)
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Darden C, Donkor J, Korolkova O, Khan Barozai MY, Chaudhuri M. Distinct structural motifs are necessary for targeting and import of Tim17 in Trypanosoma brucei mitochondrion. bioRxiv 2023:2023.07.07.548172. [PMID: 37461662 PMCID: PMC10350046 DOI: 10.1101/2023.07.07.548172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2024]
Abstract
Nuclear-encoded mitochondrial proteins are correctly translocated to their proper sub-mitochondrial destination using location specific mitochondrial targeting signals (MTSs) and via multi-protein import machineries (translocases) in the outer and inner mitochondrial membranes (TOM and TIMs, respectively). However, MTSs of multi-pass Tims are less defined. Here we report the characterization of the MTSs of Trypanosoma brucei Tim17 (TbTim17), an essential component of the most divergent TIM complex. TbTim17 possesses a characteristic secondary structure including four predicted transmembrane (TM) domains in the center with hydrophilic N- and C-termini. After examining mitochondrial localization of various deletion and site-directed mutants of TbTim17 in T. brucei using subcellular fractionation and confocal microscopy we located at least two internal signals, 1) within TM1 (31-50 AAs) and 2) TM4 + Loop 3 (120-136 AAs). Both signals are required for proper targeting and integration of TbTim17 in the membrane. Furthermore, a positively charged residue (K 122 ) is critical for mitochondrial localization of TbTim17. This is the first report of characterizing the internal mitochondrial targeting signals (ITS) for a multipass inner membrane protein in a divergent eukaryote, like T. brucei . Summary Internal targeting signals within the TM1, TM4 with Loop 3, and residue K122 are required collectively for import and integration of TbTim17 in the T. brucei mitochondrion. This information could be utilized to block parasite growth.
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Quiñones Guillén LS, Gonzalez FS, Darden C, Khan M, Tripathi A, Smith JT, Cooley A, Paromov V, Davis J, Misra S, Chaudhuri M. Unique interactions and functions of the mitochondrial small Tims in Trypanosoma brucei. bioRxiv 2023:2023.05.29.542777. [PMID: 37398442 PMCID: PMC10312748 DOI: 10.1101/2023.05.29.542777] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Trypanosoma brucei is an early divergent parasitic protozoan that causes a fatal disease, African trypanosomiasis. T. brucei possesses a unique and essential translocase of the mitochondrial inner membrane, the TbTIM17 complex. TbTim17 associates with 6 small TbTims, (TbTim9, TbTim10, TbTim11, TbTim12, TbTim13, and TbTim8/13). However, the interaction pattern of the small TbTims with each other and TbTim17 are not clear. Here, we demonstrated by yeast two-hybrid (Y2H) analysis that all six small TbTims interact with each other, but stronger interactions were found among TbTim8/13, TbTim9, and TbTim10. Each of the small TbTims also interact directly with the C-terminal region of TbTim17. RNAi studies indicated that among all small TbTims, TbTim13 is most crucial to maintain the steady-state levels of the TbTIM17 complex. Co-immunoprecipitation analyses from T. brucei mitochondrial extracts also showed that TbTim10 has a stronger association with TbTim9 and TbTim8/13, but a weaker association with TbTim13, whereas TbTim13 has a stronger connection with TbTim17. Analysis of the small TbTim complexes by size exclusion chromatography revealed that each small TbTim, except TbTim13, is present in ∼70 kDa complexes, which could be heterohexameric forms of the small TbTims. However, TbTim13 is primarily present in the larger complex (>800 kDa) and co-fractionated with TbTim17. Altogether, our results demonstrated that TbTim13 is a part of the TbTIM complex and the smaller complexes of the small TbTims likely interact with the larger complex dynamically. Therefore, relative to other eukaryotes, the architecture and function of the small TbTim complexes are specific in T. brucei .
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Chaudhuri M, Darden C, Soto Gonzalez F, Singha UK, Quinones L, Tripathi A. Tim17 Updates: A Comprehensive Review of an Ancient Mitochondrial Protein Translocator. Biomolecules 2020; 10:E1643. [PMID: 33297490 PMCID: PMC7762337 DOI: 10.3390/biom10121643] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 12/02/2020] [Accepted: 12/03/2020] [Indexed: 02/06/2023] Open
Abstract
The translocases of the mitochondrial outer and inner membranes, the TOM and TIMs, import hundreds of nucleus-encoded proteins into mitochondria. TOM and TIMs are multi-subunit protein complexes that work in cooperation with other complexes to import proteins in different sub-mitochondrial destinations. The overall architecture of these protein complexes is conserved among yeast/fungi, animals, and plants. Recent studies have revealed unique characteristics of this machinery, particularly in the eukaryotic supergroup Excavata. Despite multiple differences, homologues of Tim17, an essential component of one of the TIM complexes and a member of the Tim17/Tim22/Tim23 family, have been found in all eukaryotes. Here, we review the structure and function of Tim17 and Tim17-containing protein complexes in different eukaryotes, and then compare them to the single homologue of this protein found in Trypanosoma brucei, a unicellular parasitic protozoan.
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Affiliation(s)
- Minu Chaudhuri
- Department of Microbiology, Immunology, and Physiology, Meharry Medical College, 1005 Dr. D.B. Todd, Jr., Blvd, Nashville, TN 37208, USA; (C.D.); (F.S.G.); (U.K.S.); (L.Q.); (A.T.)
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Morgan AW, Sullivan SA, Darden C, Gregg N. Measuring the intelligence of college students with learning disabilities: a comparison of results obtained on the WAIS-R and the KAIT. J Learn Disabil 1997; 30:560-565. [PMID: 9293238 DOI: 10.1177/002221949703000512] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
This study compared results obtained on the Wechsler Adult Intelligence Scale-Revised and the Kaufman Adolescent Test and Adult Intelligence; these tests were individually administered to college students with and without learning disabilities. Participants were 30 students with learning disabilities and 30 students without learning disabilities between the ages of 18 and 30. Students were administered both IQ tests and the Peabody Picture Vocabulary Test-Revised, used as a covariate measure. The results were analyzed through a repeated-measures analysis of variance. No significant differences were found between groups or between tests. A significant difference was found for both groups when Performance IQ and Fluid Scale scores were compared.
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Affiliation(s)
- A W Morgan
- Department of Educational Psychology, University of Georgia, Athens 30602, USA
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Kim GN, Kim EJ, Son D, Bacala A, Imlay R, Kirk P, McNeil RR, Metcalf W, Cheng CP, Mao ZP, Yan Y, Xu YT, Zhu YC, Abashian A, Gotow K, Kajino F, Low E, Naito F, Piilonen L, Childers R, Darden C, Lusin S, Rosenfeld C, Wilson S, Frautschi M, Kagan H, Kass R, Trahern CG, Ko W, Lander RL, Maeshima K, Malchow RL, Higashi JR, Kurihara Y, Maki A, Nozaki T, Omori T, Perez P, Sagawa H, Sakai Y, Sugimoto Y, Takaiwa Y, Terada S, Tsuchiya K, Poling R, Green J, Park IH, Sakamoto S, Sannes F, Schnetzer S, Stone R, Trentalange S, Zimmerman D, Miyano K, Miyata H, Ogawa M, Yamashita Y, Blanis D, Bodek A, Budd H, Coombes R, Eno S, Fry CA, Harada H. Experimental mass limit for the fourth-generation sequential lepton from e+e- annihilations at sqrt s-bar=56 GeV. Phys Rev Lett 1988; 61:911-914. [PMID: 10039466 DOI: 10.1103/physrevlett.61.911] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Igarashi S, Myung SS, Chiba R, Hanaoka K, Miyashita M, Murata H, Yokota H, Bacala A, Imlay R, Kirk P, McNeil RR, Metcalf W, Cheng CP, Mao ZP, Yan Y, Xu YT, Zhou HS, Zhu YC, Abashian A, Gotow K, Kajino F, Naito F, Childers R, Darden C, Edwards J, Lusin S, Rosenfeld C, Wilson S, Johnson D, Frautschi M, Kagan H, Kass R, Trahern CG, Lee HY, Ko W, Lander RL, Maeshima K, Malchow RL, Sparks K, Williams MC, Abe K, Chakrabarti S, Fujii Y, Higashi T, Ishimoto S, Kurihara Y, Maki A, Nozaki T, Omori T, Perez P, Sagawa H, Sakai Y, Sugimoto Y, Takaiwa Y, Terada S, Tsuchiya K, Poling R, Aldritch A, Green J, Park IH, Sakamoto S, Sannes F, Schnetzer S, Stone R. Search for isolated leptons in low-thrust e+e- annihilation events at sqrt s =50 and 52 GeV. Phys Rev Lett 1988; 60:2359-2362. [PMID: 10038331 DOI: 10.1103/physrevlett.60.2359] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Sagawa H, Mori T, Abe K, Chakrabarti S, Fujii Y, Higashi Y, Ishimoto S, Kurihara Y, Maki A, Mani P, Nozaki T, Omori T, Perez P, Sakai Y, Sugimoto Y, Takaiwa Y, Terada S, Tsuchiya K, Bacala A, Imlay R, Kirk P, Marterer W, McNeil RR, Metcalf W, Cheng CP, Mao ZP, Yan Y, Xu YT, Zhou HS, Zhu YC, Abashian A, Gotow K, Kajino F, Naito F, Avignone F, Childers R, Darden C, Edwards J, Lusin S, Rosenfeld C, Wilson S, Johnson D, Frautschi M, Kagan H, Kass R, Trahern CG, Lee HY, Ko W, Lander RL, Maeshima K, Malchow RL, Saroff D, Sparks K, Williams MC, Aldritch A, Green J, Park IH, Sakamoto S, Sannes F, Schnetzer S, Stone R, Trentalange S, Zimmerman D, Miyano K. Measurements of R and a search for heavy-quark production in e+e- annihilation at sqrt s =50 and 52 GeV. Phys Rev Lett 1988; 60:93-96. [PMID: 10038207 DOI: 10.1103/physrevlett.60.93] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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