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Crameri JJ, Palmer CS, Stait T, Jackson TD, Lynch M, Sinclair A, Frajman LE, Compton AG, Coman D, Thorburn DR, Frazier AE, Stojanovski D. Reduced Protein Import via TIM23 SORT Drives Disease Pathology in TIMM50-Associated Mitochondrial Disease. Mol Cell Biol 2024; 44:226-244. [PMID: 38828998 PMCID: PMC11204040 DOI: 10.1080/10985549.2024.2353652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Accepted: 05/07/2024] [Indexed: 06/05/2024] Open
Abstract
TIMM50 is a core subunit of the TIM23 complex, the mitochondrial inner membrane translocase responsible for the import of pre-sequence-containing precursors into the mitochondrial matrix and inner membrane. Here we describe a mitochondrial disease patient who is homozygous for a novel variant in TIMM50 and establish the first proteomic map of mitochondrial disease associated with TIMM50 dysfunction. We demonstrate that TIMM50 pathogenic variants reduce the levels and activity of endogenous TIM23 complex, which significantly impacts the mitochondrial proteome, resulting in a combined oxidative phosphorylation (OXPHOS) defect and changes to mitochondrial ultrastructure. Using proteomic data sets from TIMM50 patient fibroblasts and a TIMM50 HEK293 cell model of disease, we reveal that laterally released substrates imported via the TIM23SORT complex pathway are most sensitive to loss of TIMM50. Proteins involved in OXPHOS and mitochondrial ultrastructure are enriched in the TIM23SORT substrate pool, providing a biochemical mechanism for the specific defects in TIMM50-associated mitochondrial disease patients. These results highlight the power of using proteomics to elucidate molecular mechanisms of disease and uncovering novel features of fundamental biology, with the implication that human TIMM50 may have a more pronounced role in lateral insertion than previously understood.
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Affiliation(s)
- Jordan J. Crameri
- Department of Biochemistry and Pharmacology, The University of Melbourne, Parkville, Victoria, Australia
- The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - Catherine S. Palmer
- Department of Biochemistry and Pharmacology, The University of Melbourne, Parkville, Victoria, Australia
- The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - Tegan Stait
- Murdoch Children’s Research Institute, Royal Children’s Hospital, Parkville, Victoria, Australia
- Victorian Clinical Genetics Services, Royal Children’s Hospital, Parkville, Victoria, Australia
| | - Thomas D. Jackson
- Department of Biochemistry and Pharmacology, The University of Melbourne, Parkville, Victoria, Australia
- The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - Matthew Lynch
- Neurosciences Department, Queensland Children’s Hospital, South Brisbane, Queensland, Australia
- Department of Metabolic Medicine, Queensland Children’s Hospital, South Brisbane, Queensland, Australia
- School of Medicine, University of Queensland, St Lucia, Queensland, Australia
| | - Adriane Sinclair
- Neurosciences Department, Queensland Children’s Hospital, South Brisbane, Queensland, Australia
| | - Leah E. Frajman
- Murdoch Children’s Research Institute, Royal Children’s Hospital, Parkville, Victoria, Australia
| | - Alison G. Compton
- Murdoch Children’s Research Institute, Royal Children’s Hospital, Parkville, Victoria, Australia
- Victorian Clinical Genetics Services, Royal Children’s Hospital, Parkville, Victoria, Australia
- Department of Paediatrics, The University of Melbourne, Parkville, Victoria, Australia
| | - David Coman
- Department of Metabolic Medicine, Queensland Children’s Hospital, South Brisbane, Queensland, Australia
- School of Medicine, University of Queensland, St Lucia, Queensland, Australia
| | - David R. Thorburn
- Murdoch Children’s Research Institute, Royal Children’s Hospital, Parkville, Victoria, Australia
- Victorian Clinical Genetics Services, Royal Children’s Hospital, Parkville, Victoria, Australia
- Department of Paediatrics, The University of Melbourne, Parkville, Victoria, Australia
| | - Ann E. Frazier
- Murdoch Children’s Research Institute, Royal Children’s Hospital, Parkville, Victoria, Australia
- Department of Paediatrics, The University of Melbourne, Parkville, Victoria, Australia
| | - Diana Stojanovski
- Department of Biochemistry and Pharmacology, The University of Melbourne, Parkville, Victoria, Australia
- The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria, Australia
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2
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Shi K, Shan Y, Sun X, Chen K, Luo Q, Xu Q. TP53INP2 modulates the malignant progression of colorectal cancer by reducing the inactive form of β-catenin. Biochem Biophys Res Commun 2024; 690:149275. [PMID: 37995453 DOI: 10.1016/j.bbrc.2023.149275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Accepted: 11/15/2023] [Indexed: 11/25/2023]
Abstract
TP53INP2 (tumor protein p53-inducible nuclear protein 2), known as an autophagy protein, is essential for regulating transcription and starvation-induced autophagy, which plays a crucial role in the oncogenesis and progression of various cancers. The present study aims to investigate the expression pattern, function and prognostic value of TP53INP2 in colorectal cancer (CRC). Here, we report that low expression of TP53INP2 correlates with poor survival in CRC patients. TP53INP2 was significantly downregulated in CRC tissues compared with adjacent tissues. As the malignancy of CRC progresses, the expression level of TP53INP2 gradually decreased. Knockdown of TP53INP2 promoted CRC cell proliferation and tumor growth in mice. Mechanistically, TP53INP2 deficiency decreased phosphorylation of β-catenin on S33, S37, and T41, resulting in increased accumulation of β-catenin and enhanced nuclear translocation and transcriptional activity. Moreover, we further demonstrated that TP53INP2 sequestered TIM50, thereby inhibiting its activation of β-catenin. Taken together, our findings indicate that the downregulation of TP53INP2 promotes CRC progression by activating β-catenin and suggest that TP53INP2 may be a candidate therapeutic target for CRC.
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Affiliation(s)
- Ke Shi
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, 163 Xianlin Avenue, Nanjing, 210023, China
| | - Yunlong Shan
- Key Laboratory of Drug Metabolism and Pharmacokinetics, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, 210009, China
| | - Xiao Sun
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, 163 Xianlin Avenue, Nanjing, 210023, China
| | - Kuida Chen
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, 163 Xianlin Avenue, Nanjing, 210023, China
| | - Qiong Luo
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, 163 Xianlin Avenue, Nanjing, 210023, China.
| | - Qiang Xu
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, 163 Xianlin Avenue, Nanjing, 210023, China; Jiangsu Collaborative Innovation Center of Traditional Chinese Medicine in Prevention and Treatment of Tumor, Nanjing University of Chinese Medicine, Nanjing, China.
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3
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Reed AL, Mitchell W, Alexandrescu AT, Alder NN. Interactions of amyloidogenic proteins with mitochondrial protein import machinery in aging-related neurodegenerative diseases. Front Physiol 2023; 14:1263420. [PMID: 38028797 PMCID: PMC10652799 DOI: 10.3389/fphys.2023.1263420] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 10/02/2023] [Indexed: 12/01/2023] Open
Abstract
Most mitochondrial proteins are targeted to the organelle by N-terminal mitochondrial targeting sequences (MTSs, or "presequences") that are recognized by the import machinery and subsequently cleaved to yield the mature protein. MTSs do not have conserved amino acid compositions, but share common physicochemical properties, including the ability to form amphipathic α-helical structures enriched with basic and hydrophobic residues on alternating faces. The lack of strict sequence conservation implies that some polypeptides can be mistargeted to mitochondria, especially under cellular stress. The pathogenic accumulation of proteins within mitochondria is implicated in many aging-related neurodegenerative diseases, including Alzheimer's, Parkinson's, and Huntington's diseases. Mechanistically, these diseases may originate in part from mitochondrial interactions with amyloid-β precursor protein (APP) or its cleavage product amyloid-β (Aβ), α-synuclein (α-syn), and mutant forms of huntingtin (mHtt), respectively, that are mediated in part through their associations with the mitochondrial protein import machinery. Emerging evidence suggests that these amyloidogenic proteins may present cryptic targeting signals that act as MTS mimetics and can be recognized by mitochondrial import receptors and transported into different mitochondrial compartments. Accumulation of these mistargeted proteins could overwhelm the import machinery and its associated quality control mechanisms, thereby contributing to neurological disease progression. Alternatively, the uptake of amyloidogenic proteins into mitochondria may be part of a protein quality control mechanism for clearance of cytotoxic proteins. Here we review the pathomechanisms of these diseases as they relate to mitochondrial protein import and effects on mitochondrial function, what features of APP/Aβ, α-syn and mHtt make them suitable substrates for the import machinery, and how this information can be leveraged for the development of therapeutic interventions.
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Affiliation(s)
- Ashley L. Reed
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, United States
| | - Wayne Mitchell
- Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, United States
| | - Andrei T. Alexandrescu
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, United States
| | - Nathan N. Alder
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, United States
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Zan X, Zhou Z, Wan J, Chen H, Zhu J, Xu H, Zhang J, Li X, Gao X, Chen R, Huang Z, Xu Z, Li L. Overexpression of OsHAD3, a Member of HAD Superfamily, Decreases Drought Tolerance of Rice. RICE (NEW YORK, N.Y.) 2023; 16:31. [PMID: 37468664 DOI: 10.1186/s12284-023-00647-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 07/07/2023] [Indexed: 07/21/2023]
Abstract
Haloacid dehalogenase-like hydrolase (HAD) superfamily have been shown to get involved in plant growth and abiotic stress response. Although the various functions and regulatory mechanism of HAD superfamily have been well demonstrated, we know little about the function of this family in conferring abiotic stress tolerance to rice. Here, we report OsHAD3, a HAD superfamily member, could affect drought tolerance of rice. Under drought stress, overexpression of OsHAD3 increases the accumulation of reactive oxygen species and malondialdehyde than wild type. OsHAD3-overexpression lines decreased but antisense-expression lines increased the roots length under drought stress and the transcription levels of many well-known stress-related genes were also changed in plants with different genotypes. Furthermore, overexpression of OsHAD3 also decreases the oxidative tolerance. Our results suggest that overexpression of OsHAD3 could decrease the drought tolerance of rice and provide a new strategy for improving drought tolerance in rice.
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Affiliation(s)
- Xiaofei Zan
- Rice Research Institute, Sichuan Agricultural University, Chengdu, 611130, People's Republic of China
| | - Zhanmei Zhou
- Rice Research Institute, Sichuan Agricultural University, Chengdu, 611130, People's Republic of China
| | - Jiale Wan
- Rice Research Institute, Sichuan Agricultural University, Chengdu, 611130, People's Republic of China
| | - Hao Chen
- Rice Research Institute, Sichuan Agricultural University, Chengdu, 611130, People's Republic of China
| | - Jiali Zhu
- Rice Research Institute, Sichuan Agricultural University, Chengdu, 611130, People's Republic of China
| | - Haoran Xu
- Rice Research Institute, Sichuan Agricultural University, Chengdu, 611130, People's Republic of China
| | - Jia Zhang
- Rice Research Institute, Sichuan Agricultural University, Chengdu, 611130, People's Republic of China
| | - Xiaohong Li
- Rice Research Institute, Sichuan Agricultural University, Chengdu, 611130, People's Republic of China
| | - Xiaoling Gao
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu, 611130, People's Republic of China
- Rice Research Institute, Sichuan Agricultural University, Chengdu, 611130, People's Republic of China
- Crop Ecophysiology and Cultivation Key Laboratory of Sichuan Province, Chengdu, 611130, People's Republic of China
| | - Rongjun Chen
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu, 611130, People's Republic of China
- Rice Research Institute, Sichuan Agricultural University, Chengdu, 611130, People's Republic of China
- Crop Ecophysiology and Cultivation Key Laboratory of Sichuan Province, Chengdu, 611130, People's Republic of China
| | - Zhengjian Huang
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu, 611130, People's Republic of China
- Rice Research Institute, Sichuan Agricultural University, Chengdu, 611130, People's Republic of China
- Crop Ecophysiology and Cultivation Key Laboratory of Sichuan Province, Chengdu, 611130, People's Republic of China
| | - Zhengjun Xu
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu, 611130, People's Republic of China.
- Rice Research Institute, Sichuan Agricultural University, Chengdu, 611130, People's Republic of China.
- Crop Ecophysiology and Cultivation Key Laboratory of Sichuan Province, Chengdu, 611130, People's Republic of China.
| | - Lihua Li
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu, 611130, People's Republic of China.
- Rice Research Institute, Sichuan Agricultural University, Chengdu, 611130, People's Republic of China.
- Crop Ecophysiology and Cultivation Key Laboratory of Sichuan Province, Chengdu, 611130, People's Republic of China.
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5
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Mitochondrial protein import and UPR mt in skeletal muscle remodeling and adaptation. Semin Cell Dev Biol 2023; 143:28-36. [PMID: 35063351 DOI: 10.1016/j.semcdb.2022.01.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 12/20/2021] [Accepted: 01/04/2022] [Indexed: 01/03/2023]
Abstract
The biogenesis of mitochondria requires the coordinated expression of the nuclear and the mitochondrial genomes. However, the vast majority of gene products within the organelle are encoded in the nucleus, synthesized in the cytosol, and imported into mitochondria via the protein import machinery, which permit the entry of proteins to expand the mitochondrial network. Once inside, proteins undergo a maturation and folding process brought about by enzymes comprising the unfolded protein response (UPRmt). Protein import and UPRmt activity must be synchronized and matched with mtDNA-encoded subunit synthesis for proper assembly of electron transport chain complexes to avoid proteotoxicity. This review discusses the functions of the import and UPRmt systems in mammalian skeletal muscle, as well as how exercise alters the equilibrium of these pathways in a time-dependent manner, leading to a new steady state of mitochondrial content resulting in enhanced oxidative capacity and improved muscle health.
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Wachoski-Dark E, Zhao T, Khan A, Shutt TE, Greenway SC. Mitochondrial Protein Homeostasis and Cardiomyopathy. Int J Mol Sci 2022; 23:ijms23063353. [PMID: 35328774 PMCID: PMC8953902 DOI: 10.3390/ijms23063353] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 03/15/2022] [Accepted: 03/17/2022] [Indexed: 12/06/2022] Open
Abstract
Human mitochondrial disorders impact tissues with high energetic demands and can be associated with cardiac muscle disease (cardiomyopathy) and early mortality. However, the mechanistic link between mitochondrial disease and the development of cardiomyopathy is frequently unclear. In addition, there is often marked phenotypic heterogeneity between patients, even between those with the same genetic variant, which is also not well understood. Several of the mitochondrial cardiomyopathies are related to defects in the maintenance of mitochondrial protein homeostasis, or proteostasis. This essential process involves the importing, sorting, folding and degradation of preproteins into fully functional mature structures inside mitochondria. Disrupted mitochondrial proteostasis interferes with mitochondrial energetics and ATP production, which can directly impact cardiac function. An inability to maintain proteostasis can result in mitochondrial dysfunction and subsequent mitophagy or even apoptosis. We review the known mitochondrial diseases that have been associated with cardiomyopathy and which arise from mutations in genes that are important for mitochondrial proteostasis. Genes discussed include DnaJ heat shock protein family member C19 (DNAJC19), mitochondrial import inner membrane translocase subunit TIM16 (MAGMAS), translocase of the inner mitochondrial membrane 50 (TIMM50), mitochondrial intermediate peptidase (MIPEP), X-prolyl-aminopeptidase 3 (XPNPEP3), HtraA serine peptidase 2 (HTRA2), caseinolytic mitochondrial peptidase chaperone subunit B (CLPB) and heat shock 60-kD protein 1 (HSPD1). The identification and description of disorders with a shared mechanism of disease may provide further insights into the disease process and assist with the identification of potential therapeutics.
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Affiliation(s)
- Emily Wachoski-Dark
- Department of Cardiac Sciences, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada;
- Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Tian Zhao
- Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada;
| | - Aneal Khan
- Department of Pediatrics, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada;
- Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, AB T2N 4N1, Canada
- M.A.G.I.C. Inc., Calgary, AB T2E 7Z4, Canada
| | - Timothy E. Shutt
- Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada;
- Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, AB T2N 4N1, Canada
- Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
- Correspondence: (T.E.S.); (S.C.G.)
| | - Steven C. Greenway
- Department of Cardiac Sciences, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada;
- Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
- Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada;
- Department of Pediatrics, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada;
- Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, AB T2N 4N1, Canada
- Correspondence: (T.E.S.); (S.C.G.)
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7
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Jones DE, Klacking E, Ryan RO. Inborn errors of metabolism associated with 3-methylglutaconic aciduria. Clin Chim Acta 2021; 522:96-104. [PMID: 34411555 PMCID: PMC8464523 DOI: 10.1016/j.cca.2021.08.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 08/11/2021] [Accepted: 08/13/2021] [Indexed: 11/22/2022]
Abstract
A growing number of inborn errors of metabolism (IEM) associated with compromised mitochondrial energy metabolism manifest an unusual phenotypic feature: 3-methylglutaconic (3MGC) aciduria. Two major categories of 3MGC aciduria, primary and secondary, have been described. In primary 3MGC aciduria, IEMs in 3MGC CoA hydratase (AUH) or HMG CoA lyase block leucine catabolism, resulting in a buildup of pathway intermediates, including 3MGC CoA. Subsequent thioester hydrolysis yields 3MGC acid, which is excreted in urine. In secondary 3MGC aciduria, no deficiencies in leucine catabolism enzymes exist and 3MGC CoA is formed de novo from acetyl CoA. In the "acetyl CoA diversion pathway", when IEMs directly, or indirectly, interfere with TCA cycle activity, acetyl CoA accumulates in the matrix space. This leads to condensation of two acetyl CoA to form acetoacetyl CoA, followed by another condensation between acetyl CoA and acetoacetyl CoA to form 3-hydroxy, 3-methylglutaryl (HMG) CoA. Once formed, HMG CoA serves as a substrate for AUH, producing trans-3MGC CoA. Non enzymatic isomerization of trans-3MGC CoA to cis-3MGC CoA precedes intramolecular cyclization to cis-3MGC anhydride plus CoA. Subsequent hydrolysis of cis-3MGC anhydride gives rise to cis-3MGC acid, which is excreted in urine. In reviewing 20 discrete IEMs that manifest secondary 3MGC aciduria, evidence supporting the acetyl CoA diversion pathway was obtained. This biochemical pathway serves as an "overflow valve" in muscle / brain tissue to redirect acetyl CoA to 3MGC CoA when entry to the TCA cycle is impeded.
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Affiliation(s)
- Dylan E Jones
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Reno, NV 89557, United States
| | - Emma Klacking
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Reno, NV 89557, United States
| | - Robert O Ryan
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Reno, NV 89557, United States.
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8
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Zhao F, Zou MH. Role of the Mitochondrial Protein Import Machinery and Protein Processing in Heart Disease. Front Cardiovasc Med 2021; 8:749756. [PMID: 34651031 PMCID: PMC8505727 DOI: 10.3389/fcvm.2021.749756] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 08/26/2021] [Indexed: 12/12/2022] Open
Abstract
Mitochondria are essential organelles for cellular energy production, metabolic homeostasis, calcium homeostasis, cell proliferation, and apoptosis. About 99% of mammalian mitochondrial proteins are encoded by the nuclear genome, synthesized as precursors in the cytosol, and imported into mitochondria by mitochondrial protein import machinery. Mitochondrial protein import systems function not only as independent units for protein translocation, but also are deeply integrated into a functional network of mitochondrial bioenergetics, protein quality control, mitochondrial dynamics and morphology, and interaction with other organelles. Mitochondrial protein import deficiency is linked to various diseases, including cardiovascular disease. In this review, we describe an emerging class of protein or genetic variations of components of the mitochondrial import machinery involved in heart disease. The major protein import pathways, including the presequence pathway (TIM23 pathway), the carrier pathway (TIM22 pathway), and the mitochondrial intermembrane space import and assembly machinery, related translocases, proteinases, and chaperones, are discussed here. This review highlights the importance of mitochondrial import machinery in heart disease, which deserves considerable attention, and further studies are urgently needed. Ultimately, this knowledge may be critical for the development of therapeutic strategies in heart disease.
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Affiliation(s)
- Fujie Zhao
- Center for Molecular and Translational Medicine, Georgia State University, Atlanta, GA, United States
| | - Ming-Hui Zou
- Center for Molecular and Translational Medicine, Georgia State University, Atlanta, GA, United States
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9
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Chaudhuri M, Tripathi A, Gonzalez FS. Diverse Functions of Tim50, a Component of the Mitochondrial Inner Membrane Protein Translocase. Int J Mol Sci 2021; 22:7779. [PMID: 34360547 PMCID: PMC8346121 DOI: 10.3390/ijms22157779] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 07/14/2021] [Accepted: 07/16/2021] [Indexed: 12/17/2022] Open
Abstract
Mitochondria are essential in eukaryotes. Besides producing 80% of total cellular ATP, mitochondria are involved in various cellular functions such as apoptosis, inflammation, innate immunity, stress tolerance, and Ca2+ homeostasis. Mitochondria are also the site for many critical metabolic pathways and are integrated into the signaling network to maintain cellular homeostasis under stress. Mitochondria require hundreds of proteins to perform all these functions. Since the mitochondrial genome only encodes a handful of proteins, most mitochondrial proteins are imported from the cytosol via receptor/translocase complexes on the mitochondrial outer and inner membranes known as TOMs and TIMs. Many of the subunits of these protein complexes are essential for cell survival in model yeast and other unicellular eukaryotes. Defects in the mitochondrial import machineries are also associated with various metabolic, developmental, and neurodegenerative disorders in multicellular organisms. In addition to their canonical functions, these protein translocases also help maintain mitochondrial structure and dynamics, lipid metabolism, and stress response. This review focuses on the role of Tim50, the receptor component of one of the TIM complexes, in different cellular functions, with an emphasis on the Tim50 homologue in parasitic protozoan Trypanosoma brucei.
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Affiliation(s)
- Minu Chaudhuri
- Department of Microbiology, Immunology, and Physiology, Meharry Medical College, Nashville, TN 37208, USA; (A.T.); (F.S.G.)
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10
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Molecular Insights into Mitochondrial Protein Translocation and Human Disease. Genes (Basel) 2021; 12:genes12071031. [PMID: 34356047 PMCID: PMC8305315 DOI: 10.3390/genes12071031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 06/27/2021] [Accepted: 06/30/2021] [Indexed: 12/11/2022] Open
Abstract
In human mitochondria, mtDNA encodes for only 13 proteins, all components of the OXPHOS system. The rest of the mitochondrial components, which make up approximately 99% of its proteome, are encoded in the nuclear genome, synthesized in cytosolic ribosomes and imported into mitochondria. Different import machineries translocate mitochondrial precursors, depending on their nature and the final destination inside the organelle. The proper and coordinated function of these molecular pathways is critical for mitochondrial homeostasis. Here, we will review molecular details about these pathways, which components have been linked to human disease and future perspectives on the field to expand the genetic landscape of mitochondrial diseases.
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11
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Callegari S, Cruz-Zaragoza LD, Rehling P. From TOM to the TIM23 complex - handing over of a precursor. Biol Chem 2021; 401:709-721. [PMID: 32074073 DOI: 10.1515/hsz-2020-0101] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 02/13/2020] [Indexed: 12/31/2022]
Abstract
Mitochondrial precursor proteins with amino-terminal presequences are imported via the presequence pathway, utilizing the TIM23 complex for inner membrane translocation. Initially, the precursors pass the outer membrane through the TOM complex and are handed over to the TIM23 complex where they are sorted into the inner membrane or translocated into the matrix. This handover process depends on the receptor proteins at the inner membrane, Tim50 and Tim23, which are critical for efficient import. In this review, we summarize key findings that shaped the current concepts of protein translocation along the presequence import pathway, with a particular focus on the precursor handover process from TOM to the TIM23 complex. In addition, we discuss functions of the human TIM23 pathway and the recently uncovered pathogenic mutations in TIM50.
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Affiliation(s)
- Sylvie Callegari
- Department of Cellular Biochemistry, University Medical Center Göttingen, D-37073 Göttingen, Germany
| | - Luis Daniel Cruz-Zaragoza
- Department of Cellular Biochemistry, University Medical Center Göttingen, D-37073 Göttingen, Germany
| | - Peter Rehling
- Department of Cellular Biochemistry, University Medical Center Göttingen, D-37073 Göttingen, Germany.,Max Planck Institute for Biophysical Chemistry, D-37077 Göttingen, Germany
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12
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Farouk SM, Abdellatif AM, Metwally E. Outer and inner mitochondrial membrane proteins TOMM40 and TIMM50 are intensively concentrated and localized at Purkinje and pyramidal neurons in the New Zealand white rabbit brain. Anat Rec (Hoboken) 2021; 305:209-221. [PMID: 34041863 DOI: 10.1002/ar.24689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Revised: 03/25/2021] [Accepted: 04/06/2021] [Indexed: 11/05/2022]
Abstract
Mitochondria are involved in a variety of developmental processes and neurodegenerative diseases. The translocase complexes of the outer and inner mitochondrial membranes (TOM and TIM) are protein complexes involved in transporting protein precursors across mitochondrial membranes. Although rabbits are important animal models for neurodegenerative diseases, the expression of TOM and TIM complexes has yet to be examined in the rabbit brain. In the present study, we quantitatively evaluated the protein expression of the translocase of outer mitochondrial membrane 40 (TOMM40) and inner mitochondrial membrane 50 (TIMM50) complexes, two of the TOM/TIM complexes, in the cerebral, cerebellar, and hippocampal cortices of the New Zealand white rabbit brain, using immunohistochemistry. Sections from brain specimens were initially stained for cytochrome c oxidase (COX), a well-known mitochondrial marker, which was found to be homogeneously expressed in the cerebrum, but localized to the Purkinje and pyramidal neurons of the cerebellum and hippocampus, respectively. TOMM40 and TIMM50 proteins consistently revealed a similar expression pattern, although at different ratios. In the cerebrum, TOMM40 and TIMM50 immunoreactions were homogeneously distributed within the cytoplasm of various neurons. Meanwhile, Purkinje cells in the cerebellum and pyramidal neurons in the hippocampus displayed higher intensities in their cytoplasm. The specific cellular localization of TOMM40 and TIMM50 proteins in various regions of the rabbit brain suggests a distinct function of each protein in these regions. Further analysis will be required to evaluate the molecular functions of these proteins.
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Affiliation(s)
- Sameh M Farouk
- Department of Cytology & Histology, Faculty of Veterinary Medicine, Suez Canal University, Ismailia, Egypt
| | - Ahmed M Abdellatif
- Department of Anatomy and Embryology, Faculty of Veterinary Medicine, Mansoura University, Mansoura, Egypt
| | - Elsayed Metwally
- Department of Cytology & Histology, Faculty of Veterinary Medicine, Suez Canal University, Ismailia, Egypt
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13
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Ttm50 facilitates calpain activation by anchoring it to calcium stores and increasing its sensitivity to calcium. Cell Res 2020; 31:433-449. [PMID: 32848200 DOI: 10.1038/s41422-020-0388-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2020] [Accepted: 07/20/2020] [Indexed: 11/08/2022] Open
Abstract
Calcium-dependent proteolytic calpains are implicated in a variety of physiological processes, as well as pathologies associated with calcium overload. However, the mechanism by which calpain is activated remains elusive since intracellular calcium levels under physiological conditions do not reach the high concentration range required to trigger calpain activation. From a candidate screening using the abundance of the calpain target glutamate receptor GluRIIA at the Drosophila neuromuscular junction as a readout, we uncovered that calpain activity was inhibited upon knockdown of Ttm50, a subunit of the Tim23 complex known to be involved in the import of proteins across the mitochondrial inner membrane. Unexpectedly, Ttm50 and calpain are co-localized at calcium stores Golgi and endoplasmic reticulum (ER), and Ttm50 interacts with calpain via its C-terminal domain. This interaction is required for calpain localization at Golgi/ER, and increases calcium sensitivity of calpain by roughly an order of magnitude. Our findings reveal the regulation of calpain activation by Ttm50, and shed new light on calpain-associated pathologies.
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14
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Yang L, Kong D, He M, Gong J, Nie Y, Tai S, Teng CB. MiR-7 mediates mitochondrial impairment to trigger apoptosis and necroptosis in Rhabdomyosarcoma. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2020; 1867:118826. [PMID: 32810522 DOI: 10.1016/j.bbamcr.2020.118826] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 07/25/2020] [Accepted: 08/12/2020] [Indexed: 02/06/2023]
Abstract
BACKGROUND Rhabdomyosarcoma (RMS) is a pediatric cancer with rhabdomyoblastic phenotype and mitochondria act as pivotal regulators of its growth and progression. While miR-7-5p (miR-7) is reported to have a tumor-suppressive role, little is yet known about its antitumor activity in RMS. METHODS The effects of miR-7 on RMS were analyzed both in vitro and in vivo. Cell death modalities induced by miR-7 were identified. Influence on mitochondria was evaluated through RNA sequencing data, morphological observation and mitochondrial functional assays, including outer membrane permeability, bioenergetics and redox balance. Dual-luciferase assay and phenotype validation after transient gene silencing were performed to identify miR-7 targets in RMS. RESULTS MiR-7 executed anti-tumor effect in RMS beyond proliferation inhibition. Morphologic features and molecular characteristics with apoptosis and necroptosis were found in miR-7-transfected RMS cells. Chemical inhibitors of apoptosis and necroptosis were able to prevent miR-7-induced cell death. Further, we identified that mitochondrial impairment mainly contributed to these phenomena and mitochondrial proteins SLC25A37 and TIMM50 were crucial targets for miR-7 to induce cell death in RMS. CONCLUSION Our results extended the mechanism of miR-7 antitumor role in rhabdomyosarcoma cancer, and provided potential implications for its therapy.
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Affiliation(s)
- Lin Yang
- Key Laboratory of Saline-alkali Vegetation Ecology Restoration, College of Life Science, Northeast Forestry University, Harbin, China
| | - Delin Kong
- Key Laboratory of Saline-alkali Vegetation Ecology Restoration, College of Life Science, Northeast Forestry University, Harbin, China
| | - Mei He
- Key Laboratory of Saline-alkali Vegetation Ecology Restoration, College of Life Science, Northeast Forestry University, Harbin, China
| | - Jiawei Gong
- Key Laboratory of Saline-alkali Vegetation Ecology Restoration, College of Life Science, Northeast Forestry University, Harbin, China
| | - Yuzhe Nie
- Key Laboratory of Saline-alkali Vegetation Ecology Restoration, College of Life Science, Northeast Forestry University, Harbin, China
| | - Sheng Tai
- Department of Hepatopancreatobiliary Surgery, Second Affiliated Hospital of Harbin Medical University, Harbin, China.
| | - Chun-Bo Teng
- Key Laboratory of Saline-alkali Vegetation Ecology Restoration, College of Life Science, Northeast Forestry University, Harbin, China.
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15
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Zhou H, Wang H, Yu M, Schugar RC, Qian W, Tang F, Liu W, Yang H, McDowell RE, Zhao J, Gao J, Dongre A, Carman JA, Yin M, Drazba JA, Dent R, Hine C, Chen YR, Smith JD, Fox PL, Brown JM, Li X. IL-1 induces mitochondrial translocation of IRAK2 to suppress oxidative metabolism in adipocytes. Nat Immunol 2020; 21:1219-1231. [PMID: 32778760 PMCID: PMC7566776 DOI: 10.1038/s41590-020-0750-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 06/25/2020] [Indexed: 12/14/2022]
Abstract
Chronic inflammation is a common feature of obesity with elevated cytokines such as Interleukin-1 (IL-1) in circulation and tissues. Here, we report an unconventional IL-1R-MyD88-IRAK2-PHB/OPA1 signaling axis that reprograms mitochondrial metabolism in adipocytes to exacerbate obesity. IL-1 induced recruitment of IRAK2-Myddosome to mitochondria outer membrane via recognition by TOM20, followed by TIMM50-guided translocation of IRAK2 into mitochondria inner membrane to suppress oxidative phosphorylation and fatty acid oxidation, thereby, attenuating energy expenditure. Adipocyte-specific MyD88 or IRAK2 deficiency reduced high fat diet (HFD)-induced weight gain, increased energy expenditure and ameliorated insulin resistance, associated with a smaller adipocyte size and increased cristae formation. IRAK2 kinase inactivation also reduced HFD-induced metabolic diseases. Mechanistically, IRAK2 suppressed respiratory super-complex formation via interaction with PHB1 and OPA1 upon stimulation of IL-1. Taken together, our results suggest that IRAK2 Myddosome functions as a critical link between inflammation and metabolism, representing a novel therapeutic target for patients with obesity.
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Affiliation(s)
- Hao Zhou
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Han Wang
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA.,School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Minjia Yu
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA.,Department of Medicine, Mount Auburn Hospital, Harvard Medical School, Cambridge, MA, USA
| | - Rebecca C Schugar
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Wen Qian
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Fangqiang Tang
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Weiwei Liu
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Hui Yang
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Ruth E McDowell
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Junjie Zhao
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Ji Gao
- Discovery Biology, Bristol Myers Squibb, Princeton, NJ, USA
| | - Ashok Dongre
- Discovery Biology, Bristol Myers Squibb, Princeton, NJ, USA
| | - Julie A Carman
- Discovery Biology, Bristol Myers Squibb, Princeton, NJ, USA.,Immunology Discovery, Janssen Research and Development, Spring House, PA, USA
| | - Mei Yin
- Imaging Core, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Judith A Drazba
- Imaging Core, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Robert Dent
- University of Ottawa and Ottawa Hospital, Ottawa, Ontario, Canada
| | - Christopher Hine
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Yeong-Renn Chen
- Department of Integrative Medical Sciences, College of Medicine, Northeast Ohio Medical University, Rootstown, OH, USA
| | - Jonathan D Smith
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Paul L Fox
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - J Mark Brown
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Xiaoxia Li
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA.
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16
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Reiterer V, Pawłowski K, Desrochers G, Pause A, Sharpe HJ, Farhan H. The dead phosphatases society: a review of the emerging roles of pseudophosphatases. FEBS J 2020; 287:4198-4220. [PMID: 32484316 DOI: 10.1111/febs.15431] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 05/12/2020] [Accepted: 05/27/2020] [Indexed: 12/11/2022]
Abstract
Phosphatases are a diverse family of enzymes, comprising at least 10 distinct protein folds. Like most other enzyme families, many have sequence variations that predict an impairment or loss of catalytic activity classifying them as pseudophosphatases. Research on pseudoenzymes is an emerging area of interest, with new biological functions repurposed from catalytically active relatives. Here, we provide an overview of the pseudophosphatases identified to date in all major phosphatase families. We will highlight the degeneration of the various catalytic sequence motifs and discuss the challenges associated with the experimental determination of catalytic inactivity. We will also summarize the role of pseudophosphatases in various diseases and discuss the major challenges and future directions in this field.
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Affiliation(s)
| | | | - Guillaume Desrochers
- Department of Biochemistry, McGill University, Montréal, QC, Canada.,Goodman Cancer Research Centre, McGill University, Montréal, QC, Canada
| | - Arnim Pause
- Department of Biochemistry, McGill University, Montréal, QC, Canada.,Goodman Cancer Research Centre, McGill University, Montréal, QC, Canada
| | | | - Hesso Farhan
- Institute of Basic Medical Sciences, University of Oslo, Norway
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17
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Azevedo RDS, Falcão KVG, Amaral IPG, Leite ACR, Bezerra RS. Mitochondria as targets for toxicity and metabolism research using zebrafish. Biochim Biophys Acta Gen Subj 2020; 1864:129634. [PMID: 32417171 DOI: 10.1016/j.bbagen.2020.129634] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Revised: 05/09/2020] [Accepted: 05/11/2020] [Indexed: 12/27/2022]
Abstract
BACKGROUND The study of mitochondrial functions in zebrafish was initiated before the 1990s and has effectively supported many of the recent scientific advances in the functional studies of mitochondria. SCOPE OF REVIEW This work elaborates various peculiarities and general advances in the study of mitochondria using this animal model. MAJOR CONCLUSIONS The inclusion of zebrafish models in scientific research was initiated with structural studies of mitochondria. Then, toxicological studies involving chemical compounds were undertaken. Currently, there is a decisive tendency to use zebrafish to understand how chemicals impair mitochondrial bioenergetics. Zebrafish modeling has been fruitful for the analysis of ion homeostasis, especially for Ca2+ transport, since zebrafish and mammals have the same set of Ca2+ transporters and mitochondrial membrane microdomains. Based on zebrafish embryo studies, our understanding of ROS generation has also led to new insights. GENERAL SIGNIFICANCE For the study of mitochondria, a new era was begun with the inclusion of zebrafish in bioenergetics research.
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Affiliation(s)
- Rafael D S Azevedo
- Biochemistry Department, Federal University of Pernambuco - UFPE, Recife, PE, Brazil.
| | - Kivia V G Falcão
- Biochemistry Department, Federal University of Pernambuco - UFPE, Recife, PE, Brazil
| | - Ian P G Amaral
- Biotechnology Center, Federal University of Paraiba - UFPB, João Pessoa, PB, Brazil
| | - Ana C R Leite
- Institute of Chemistry and Biotecnhology, Federal University of Alagoas - UFAL, Maceió, AL, Brazil
| | - Ranilson S Bezerra
- Biochemistry Department, Federal University of Pernambuco - UFPE, Recife, PE, Brazil
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18
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Tripathi A, Singha UK, Paromov V, Hill S, Pratap S, Rose K, Chaudhuri M. The Cross Talk between TbTim50 and PIP39, Two Aspartate-Based Protein Phosphatases, Maintains Cellular Homeostasis in Trypanosoma brucei. mSphere 2019; 4:e00353-19. [PMID: 31391278 PMCID: PMC6686227 DOI: 10.1128/msphere.00353-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 07/08/2019] [Indexed: 12/18/2022] Open
Abstract
Trypanosoma brucei, the infectious agent of a deadly disease known as African trypanosomiasis, undergoes various stresses during its digenetic life cycle. We previously showed that downregulation of T. brucei mitochondrial inner membrane protein translocase 50 (TbTim50), an aspartate-based protein phosphatase and a component of the translocase of the mitochondrial inner membrane (TIM), increased the tolerance of procyclic cells to oxidative stress. Using comparative proteomics analysis and further validating the proteomics results by immunoblotting, here we discovered that TbTim50 downregulation caused an approximately 5-fold increase in the levels of PIP39, which is also an aspartate-based protein phosphatase and is primarily localized in glycosomes. A moderate upregulation of a number of glycosomal enzymes was also noticed due to TbTim50 knockdown. We found that the rate of mitochondrial ATP production by oxidative phosphorylation decreased and that substrate-level phosphorylation increased due to depletion of TbTim50. These results were correlated with relative increases in the levels of trypanosome alternative oxidase and hexokinase and a reduced-growth phenotype in low-glucose medium. The levels and activity of the mitochondrial superoxide dismutase and glutaredoxin levels were increased due to TbTim50 knockdown. Furthermore, we show that TbTim50 downregulation increased the cellular AMP/ATP ratio, and as a consequence, phosphorylation of AMP-activated protein kinase (AMPK) was increased. Knocking down both TbTim50 and TbPIP39 reduced PIP39 levels as well as AMPK phosphorylation and reduced T. brucei tolerance to oxidative stress. These results suggest that TbTim50 and PIP39, two protein phosphatases in mitochondria and glycosomes, respectively, cross talk via the AMPK pathway to maintain cellular homeostasis in the procyclic form of T. bruceiIMPORTANCETrypanosoma brucei, the infectious agent of African trypanosomiasis, must adapt to strikingly different host environments during its digenetic life cycle. Developmental regulation of mitochondrial activities is an essential part of these processes. We have shown previously that mitochondrial inner membrane protein translocase 50 in T. brucei (TbTim50) possesses a dually specific phosphatase activity and plays a role in the cellular stress response pathway. Using proteomics analysis, here we have elucidated a novel connection between TbTim50 and a protein phosphatase of the same family, PIP39, which is also a differentiation-related protein localized in glycosomes. We found that these two protein phosphatases cross talk via the AMPK pathway and modulate cellular metabolic activities under stress. Together, our results indicate the importance of a TbTim50 and PIP39 cascade for communication between mitochondria and other cellular parts in regulation of cell homeostasis in T. brucei.
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Affiliation(s)
- Anuj Tripathi
- Department of Microbiology, Immunology, and Physiology, Meharry Medical College, Nashville, Tennessee, USA
| | - Ujjal K Singha
- Department of Microbiology, Immunology, and Physiology, Meharry Medical College, Nashville, Tennessee, USA
| | - Victor Paromov
- Department of Microbiology, Immunology, and Physiology, Meharry Medical College, Nashville, Tennessee, USA
| | - Salisha Hill
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee, USA
| | - Siddharth Pratap
- Department of Microbiology, Immunology, and Physiology, Meharry Medical College, Nashville, Tennessee, USA
| | - Kristie Rose
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee, USA
| | - Minu Chaudhuri
- Department of Microbiology, Immunology, and Physiology, Meharry Medical College, Nashville, Tennessee, USA
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19
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Tort F, Ugarteburu O, Texidó L, Gea-Sorlí S, García-Villoria J, Ferrer-Cortès X, Arias Á, Matalonga L, Gort L, Ferrer I, Guitart-Mampel M, Garrabou G, Vaz FM, Pristoupilova A, Rodríguez MIE, Beltran S, Cardellach F, Wanders RJ, Fillat C, García-Silva MT, Ribes A. Mutations in TIMM50 cause severe mitochondrial dysfunction by targeting key aspects of mitochondrial physiology. Hum Mutat 2019; 40:1700-1712. [PMID: 31058414 DOI: 10.1002/humu.23779] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 04/26/2019] [Accepted: 04/28/2019] [Indexed: 01/16/2023]
Abstract
3-Methylglutaconic aciduria (3-MGA-uria) syndromes comprise a heterogeneous group of diseases associated with mitochondrial membrane defects. Whole-exome sequencing identified compound heterozygous mutations in TIMM50 (c.[341 G>A];[805 G>A]) in a boy with West syndrome, optic atrophy, neutropenia, cardiomyopathy, Leigh syndrome, and persistent 3-MGA-uria. A comprehensive analysis of the mitochondrial function was performed in fibroblasts of the patient to elucidate the molecular basis of the disease. TIMM50 protein was severely reduced in the patient fibroblasts, regardless of the normal mRNA levels, suggesting that the mutated residues might be important for TIMM50 protein stability. Severe morphological defects and ultrastructural abnormalities with aberrant mitochondrial cristae organization in muscle and fibroblasts were found. The levels of fully assembled OXPHOS complexes and supercomplexes were strongly reduced in fibroblasts from this patient. High-resolution respirometry demonstrated a significant reduction of the maximum respiratory capacity. A TIMM50-deficient HEK293T cell line that we generated using CRISPR/Cas9 mimicked the respiratory defect observed in the patient fibroblasts; notably, this defect was rescued by transfection with a plasmid encoding the TIMM50 wild-type protein. In summary, we demonstrated that TIMM50 deficiency causes a severe mitochondrial dysfunction by targeting key aspects of mitochondrial physiology, such as the maintenance of proper mitochondrial morphology, OXPHOS assembly, and mitochondrial respiratory capacity.
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Affiliation(s)
- Frederic Tort
- Secció d'Errors Congènits del Metabolisme -IBC, Servei de Bioquímica i Genètica Molecular, Hospital Clínic, IDIBAPS, CIBERER, Barcelona, Spain
| | - Olatz Ugarteburu
- Secció d'Errors Congènits del Metabolisme -IBC, Servei de Bioquímica i Genètica Molecular, Hospital Clínic, IDIBAPS, CIBERER, Barcelona, Spain
| | - Laura Texidó
- Secció d'Errors Congènits del Metabolisme -IBC, Servei de Bioquímica i Genètica Molecular, Hospital Clínic, IDIBAPS, CIBERER, Barcelona, Spain
| | - Sabrina Gea-Sorlí
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Universitat de Barcelona, Barcelona, Spain
| | - Judit García-Villoria
- Secció d'Errors Congènits del Metabolisme -IBC, Servei de Bioquímica i Genètica Molecular, Hospital Clínic, IDIBAPS, CIBERER, Barcelona, Spain
| | - Xènia Ferrer-Cortès
- Secció d'Errors Congènits del Metabolisme -IBC, Servei de Bioquímica i Genètica Molecular, Hospital Clínic, IDIBAPS, CIBERER, Barcelona, Spain
| | - Ángela Arias
- Secció d'Errors Congènits del Metabolisme -IBC, Servei de Bioquímica i Genètica Molecular, Hospital Clínic, IDIBAPS, CIBERER, Barcelona, Spain
| | - Leslie Matalonga
- Secció d'Errors Congènits del Metabolisme -IBC, Servei de Bioquímica i Genètica Molecular, Hospital Clínic, IDIBAPS, CIBERER, Barcelona, Spain
| | - Laura Gort
- Secció d'Errors Congènits del Metabolisme -IBC, Servei de Bioquímica i Genètica Molecular, Hospital Clínic, IDIBAPS, CIBERER, Barcelona, Spain
| | - Isidre Ferrer
- Department of Pathology and Experimental Therapeutics, University of Barcelona; Bellvitge University Hospital; IDIBELL; Network Biomedical Research Center of Neurodegenerative diseases (CIBERNED), Hospitalet de Llobregat, Barcelona, Spain
| | - Mariona Guitart-Mampel
- Muscle Research and Mitochondrial Function Laboratory, Cellex-IDIBAPS, Faculty of Medicine and Health Science-University of Barcelona, Internal Medicine Service-Hospital Clínic of Barcelona, CIBERER, Barcelona, Spain
| | - Glòria Garrabou
- Muscle Research and Mitochondrial Function Laboratory, Cellex-IDIBAPS, Faculty of Medicine and Health Science-University of Barcelona, Internal Medicine Service-Hospital Clínic of Barcelona, CIBERER, Barcelona, Spain
| | - Frederick M Vaz
- Departments of Clinical Chemistry and Pediatrics, Laboratory Genetic Metabolic Diseases, University of Amsterdam, Amsterdam, The Netherlands
| | - Ana Pristoupilova
- Department of Pediatrics and Adolescent Medicine, Research Unit for Rare Diseases, First Faculty of Medicine, Charles University, Prague, Czech Republic.,Centre for Genomic Regulation (CRG), CNAG-CRG, Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
| | | | - Sergi Beltran
- Centre for Genomic Regulation (CRG), CNAG-CRG, Barcelona Institute of Science and Technology (BIST), Barcelona, Spain.,Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Francesc Cardellach
- Muscle Research and Mitochondrial Function Laboratory, Cellex-IDIBAPS, Faculty of Medicine and Health Science-University of Barcelona, Internal Medicine Service-Hospital Clínic of Barcelona, CIBERER, Barcelona, Spain
| | - Ronald Ja Wanders
- Departments of Clinical Chemistry and Pediatrics, Laboratory Genetic Metabolic Diseases, University of Amsterdam, Amsterdam, The Netherlands
| | - Cristina Fillat
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Universitat de Barcelona, Barcelona, Spain
| | - María Teresa García-Silva
- Unidad de Enfermedades Mitocondriales- Enfermedades Metabólicas Hereditarias. Servicio de Pediatría. Universitary Hospital 12 de Octubre, U723 CIBERER, Universidad Complutense, Madrid, Spain
| | - Antonia Ribes
- Secció d'Errors Congènits del Metabolisme -IBC, Servei de Bioquímica i Genètica Molecular, Hospital Clínic, IDIBAPS, CIBERER, Barcelona, Spain
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20
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Zhang X, Han S, Zhou H, Cai L, Li J, Liu N, Liu Y, Wang L, Fan C, Li A, Miao Y. TIMM50 promotes tumor progression via ERK signaling and predicts poor prognosis of non-small cell lung cancer patients. Mol Carcinog 2019; 58:767-776. [PMID: 30604908 DOI: 10.1002/mc.22969] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Revised: 12/15/2018] [Accepted: 12/27/2018] [Indexed: 12/13/2022]
Abstract
TIMM50 (Translocase of the inner mitochondrial membrane 50), also called TIM50, plays an essential role in mitochondrial membrane transportation. The existing literature suggests that TIMM50 may perform as an oncogenetic protein in breast cancer. However, the molecular mechanism, especially in human non-small cell lung cancer (NSCLC), is uncertain to date. In the present study, using immunohistochemistry, we found that TIMM50 expression significantly correlated with larger tumor size (P = 0.049), advanced TNM stage (P = 0.001), positive regional lymph node metastasis (P = 0.007), and poor overall survival (P = 0.001). Proliferation and invasion assay showed that TIMM50 dramatically promoted the ability of proliferation and invasion of NSCLC cells. Subsequent Western blotting results revealed that TIMM50 enhanced the expression of Cyclin D1 and Snail, and inhibited the expression of E-cadherin. Moreover, TIMM50 facilitated the expression of phosphorylated ERK and P90RSK. Incorporation of ERK inhibitor counteracted the upregulating expression of CyclinD1, and Snail, and downregulating expression of E-cadherin expression induced by TIMM50 overexpression. In conclusion, our data indicated that TIMM50 facilitated tumor proliferation and invasion of NSCLC through enhancing phosphorylation of its downstream ERK/P90RSK signaling pathway. We speculated that TIMM50 might be a useful prognosis marker of NSCLC patients.
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Affiliation(s)
- Xiupeng Zhang
- Department of Pathology, College of Basic Medical Science and the First Affiliated Hospital of China Medical University, Shenyang, China
| | - Shuai Han
- Department of Neurosurgery, The First Hospital of China Medical University, Shenyang, China
| | - Haijing Zhou
- Department of Pathology, College of Basic Medical Science and the First Affiliated Hospital of China Medical University, Shenyang, China
| | - Lin Cai
- Department of Pathology, College of Basic Medical Science and the First Affiliated Hospital of China Medical University, Shenyang, China
| | - Jingduo Li
- Department of Pathology, College of Basic Medical Science and the First Affiliated Hospital of China Medical University, Shenyang, China
| | - Nan Liu
- Department of Pathology, College of Basic Medical Science and the First Affiliated Hospital of China Medical University, Shenyang, China
| | - Yang Liu
- Department of Pathology, College of Basic Medical Science and the First Affiliated Hospital of China Medical University, Shenyang, China
| | - Liang Wang
- Department of Pathology, College of Basic Medical Science and the First Affiliated Hospital of China Medical University, Shenyang, China
| | - Chuifeng Fan
- Department of Pathology, College of Basic Medical Science and the First Affiliated Hospital of China Medical University, Shenyang, China
| | - Ailin Li
- Department of Radiotherapy, The First Affiliated Hospital of China Medical University, Shenyang, China
| | - Yuan Miao
- Department of Pathology, College of Basic Medical Science and the First Affiliated Hospital of China Medical University, Shenyang, China
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21
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Inner Mitochondrial Translocase Tim50 Is Central in Adrenal and Testicular Steroid Synthesis. Mol Cell Biol 2018; 39:MCB.00484-18. [PMID: 30348838 DOI: 10.1128/mcb.00484-18] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2018] [Accepted: 10/14/2018] [Indexed: 01/24/2023] Open
Abstract
Adrenal and gonadal mitochondrial metabolic activity requires electrons from cofactors, cholesterol, and a substrate for rapid steroid synthesis, an essential requirement for mammalian survival. Substrate activity depends on its environment, which is regulated by chaperones and mitochondrial translocases. Cytochrome P450 side-chain cleavage enzyme (SCC or CYP11A1) catalyzes cholesterol to pregnenolone conversion, although its mechanism of action is not well understood. We find that SCC is directly imported into the mitochondrial matrix, where its N-terminal sequence is cleaved sequentially, after which it becomes activated following the second cleavage, which is dependent on the folding of the protein. Following integration of the SCC C terminus into the TIM23 complex, amino acids 141 to 146 interact with the intermembrane-exposed Tim50 protein, forming a large complex. The absence of Tim50 or its mutation reduced enzymatic activity. For the first time, we report that a protein activated at the matrix remains mostly unfolded and is transported back to the IMS to integrate with the TIM23 translocase complex and align with the Tim50 protein. Amino acid changes that suppress the association of Tim50 with SCC ablate metabolic activity. Thus, the TIM23 complex is the central regulator of metabolism guided by Tim50.
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Mitochondrial diseases caused by dysfunctional mitochondrial protein import. Biochem Soc Trans 2018; 46:1225-1238. [PMID: 30287509 DOI: 10.1042/bst20180239] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 08/20/2018] [Accepted: 08/31/2018] [Indexed: 12/18/2022]
Abstract
Mitochondria are essential organelles which perform complex and varied functions within eukaryotic cells. Maintenance of mitochondrial health and functionality is thus a key cellular priority and relies on the organelle's extensive proteome. The mitochondrial proteome is largely encoded by nuclear genes, and mitochondrial proteins must be sorted to the correct mitochondrial sub-compartment post-translationally. This essential process is carried out by multimeric and dynamic translocation and sorting machineries, which can be found in all four mitochondrial compartments. Interestingly, advances in the diagnosis of genetic disease have revealed that mutations in various components of the human import machinery can cause mitochondrial disease, a heterogenous and often severe collection of disorders associated with energy generation defects and a multisystem presentation often affecting the cardiovascular and nervous systems. Here, we review our current understanding of mitochondrial protein import systems in human cells and the molecular basis of mitochondrial diseases caused by defects in these pathways.
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Reyes A, Melchionda L, Burlina A, Robinson AJ, Ghezzi D, Zeviani M. Mutations in TIMM50 compromise cell survival in OxPhos-dependent metabolic conditions. EMBO Mol Med 2018; 10:emmm.201708698. [PMID: 30190335 PMCID: PMC6180300 DOI: 10.15252/emmm.201708698] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
TIMM50 is an essential component of the TIM23 complex, the mitochondrial inner membrane machinery that imports cytosolic proteins containing a mitochondrial targeting presequence into the mitochondrial inner compartment. Whole exome sequencing (WES) identified compound heterozygous pathogenic mutations in TIMM50 in an infant patient with rapidly progressive, severe encephalopathy. Patient fibroblasts presented low levels of TIMM50 and other components of the TIM23 complex, lower mitochondrial membrane potential, and impaired TIM23-dependent protein import. As a consequence, steady-state levels of several components of mitochondrial respiratory chain were decreased, resulting in decreased respiration and increased ROS production. Growth of patient fibroblasts in galactose shifted energy production metabolism toward oxidative phosphorylation (OxPhos), producing an apparent improvement in most of the above features but also increased apoptosis. Complementation of patient fibroblasts with TIMM50 improved or restored these features to control levels. Moreover, RNASEH1 and ISCU mutant fibroblasts only shared a few of these features with TIMM50 mutant fibroblasts. Our results indicate that mutations in TIMM50 cause multiple mitochondrial bioenergetic dysfunction and that functional TIMM50 is essential for cell survival in OxPhos-dependent conditions.
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Affiliation(s)
- Aurelio Reyes
- MRC Mitochondrial Biology UnitUniversity of CambridgeCambridgeUK
| | - Laura Melchionda
- Unit of Molecular NeurogeneticsFoundation Carlo Besta Neurological Institute‐IRCCSMilanItaly
| | - Alberto Burlina
- Division of Inherited Metabolic DiseasesDepartment of PediatricsUniversity Hospital PadovaPadovaItaly
| | - Alan J Robinson
- MRC Mitochondrial Biology UnitUniversity of CambridgeCambridgeUK
| | - Daniele Ghezzi
- Unit of Molecular NeurogeneticsFoundation Carlo Besta Neurological Institute‐IRCCSMilanItaly
| | - Massimo Zeviani
- MRC Mitochondrial Biology UnitUniversity of CambridgeCambridgeUK
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Chen X, Wong YK, Lim TK, Lim WH, Lin Q, Wang J, Hua Z. Artesunate Activates the Intrinsic Apoptosis of HCT116 Cells through the Suppression of Fatty Acid Synthesis and the NF-κB Pathway. Molecules 2017; 22:E1272. [PMID: 28786914 PMCID: PMC6152404 DOI: 10.3390/molecules22081272] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Revised: 07/27/2017] [Accepted: 07/27/2017] [Indexed: 11/16/2022] Open
Abstract
The artemisinin compounds, which are well-known for their potent therapeutic antimalarial activity, possess in vivo and in vitro antitumor effects. Although the anticancer effect of artemisinin compounds has been extensively reported, the precise mechanisms underlying its cytotoxicity remain under intensive study. In the present study, a high-throughput quantitative proteomics approach was applied to identify differentially expressed proteins of HCT116 colorectal cancer cell line with artesunate (ART) treatment. Through Ingenuity Pathway Analysis, we discovered that the top-ranked ART-regulated biological pathways are abrogation of fatty acid biosynthetic pathway and mitochondrial dysfunction. Subsequent assays showed that ART inhibits HCT116 cell proliferation through suppressing the fatty acid biosynthetic pathway and activating the mitochondrial apoptosis pathway. In addition, ART also regulates several proteins that are involved in NF-κB pathway, and our subsequent assays showed that ART suppresses the NF-κB pathway. These proteomic findings will contribute to improving our understanding of the underlying molecular mechanisms of ART for its therapeutic cytotoxic effect towards cancer cells.
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Affiliation(s)
- Xiao Chen
- The State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, China.
| | - Yin Kwan Wong
- Department of Biological Science, National University of Singapore, Singapore 117543, Singapore.
| | - Teck Kwang Lim
- Department of Biological Science, National University of Singapore, Singapore 117543, Singapore.
| | - Wei Hou Lim
- Department of Biological Science, National University of Singapore, Singapore 117543, Singapore.
| | - Qingsong Lin
- Department of Biological Science, National University of Singapore, Singapore 117543, Singapore.
| | - Jigang Wang
- Department of Biological Science, National University of Singapore, Singapore 117543, Singapore.
- Changzhou High-Tech Research Institute of Nanjing University, Institute of Biotechnology, Jiangsu Industrial Technology Research Institute and Jiangsu TargetPharma Laboratories Inc., Changzhou 213164, China.
| | - Zichun Hua
- The State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, China.
- Changzhou High-Tech Research Institute of Nanjing University, Institute of Biotechnology, Jiangsu Industrial Technology Research Institute and Jiangsu TargetPharma Laboratories Inc., Changzhou 213164, China.
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Kang Y, Fielden LF, Stojanovski D. Mitochondrial protein transport in health and disease. Semin Cell Dev Biol 2017; 76:142-153. [PMID: 28765093 DOI: 10.1016/j.semcdb.2017.07.028] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 07/18/2017] [Accepted: 07/19/2017] [Indexed: 01/17/2023]
Abstract
Mitochondria are fundamental structures that fulfil important and diverse functions within cells, including cellular respiration and iron-sulfur cluster biogenesis. Mitochondrial function is reliant on the organelles proteome, which is maintained and adjusted depending on cellular requirements. The majority of mitochondrial proteins are encoded by nuclear genes and must be trafficked to, and imported into the organelle following synthesis in the cytosol. These nuclear-encoded mitochondrial precursors utilise dynamic and multimeric translocation machines to traverse the organelles membranes and be partitioned to the appropriate mitochondrial subcompartment. Yeast model systems have been instrumental in establishing the molecular basis of mitochondrial protein import machines and mechanisms, however unique players and mechanisms are apparent in higher eukaryotes. Here, we review our current knowledge on mitochondrial protein import in human cells and how dysfunction in these pathways can lead to disease.
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Affiliation(s)
- Yilin Kang
- Department of Biochemistry and Molecular Biology and The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Laura F Fielden
- Department of Biochemistry and Molecular Biology and The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Diana Stojanovski
- Department of Biochemistry and Molecular Biology and The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria, 3010, Australia.
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Tang K, Zhao Y, Li H, Zhu M, Li W, Liu W, Zhu G, Xu D, Peng W, Xu YW. Translocase of Inner Membrane 50 Functions as a Novel Protective Regulator of Pathological Cardiac Hypertrophy. J Am Heart Assoc 2017; 6:JAHA.116.004346. [PMID: 28432072 PMCID: PMC5532988 DOI: 10.1161/jaha.116.004346] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
BACKGROUND Translocase of inner membrane 50 (TIM50) is a member of the translocase of inner membrane (TIM) complex in the mitochondria. Previous research has demonstrated the role of TIM50 in the regulation of oxidative stress and cardiac morphology. However, the role of TIM50 in pathological cardiac hypertrophy remains unknown. METHODS AND RESULTS In the present study we found that the expression of TIM50 was downregulated in hypertrophic hearts. Using genetic loss-of-function animal models, we demonstrated that TIM50 deficiency increased heart and cardiomyocyte size with more severe cardiac fibrosis compared with wild-type littermates. Moreover, we generated cardiomyocyte-specific TIM50 transgenic mice in which the hypertrophic and fibrotic phenotypes were all alleviated. Next, we tested reactive oxygen species generation and the activities of the antioxidant enzymes superoxide dismutase and catalase, and also respiratory chain complexes I, II, and IV, finding that all the activities were regulated by TIM50. Meanwhile, expression of the ASK1-JNK/P38 axis was increased in TIM50-deficient mice, and TIM50 overexpression decreased the activity of the ASK1-JNK/P38 axis. Finally, we treated mice with the antioxidant N-acetyl cysteine to reduce oxidative stress. After N-acetyl cysteine treatment, the deteriorative hypertrophic and fibrotic phenotypes caused by TIM50 deficiency were all remarkably reversed. CONCLUSIONS These data indicated that TIM50 could attenuate pathological cardiac hypertrophy primarily by reducing oxidative stress. TIM50 could be a promising target for the prevention and therapy of cardiac hypertrophy and heart failure.
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Affiliation(s)
- Kai Tang
- Department of Cardiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
| | - Yifan Zhao
- Department of Cardiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
| | - Hailing Li
- Department of Cardiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
| | - Mengyun Zhu
- Department of Cardiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
| | - Weiming Li
- Department of Cardiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
| | - Weijing Liu
- Department of Cardiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
| | - Guofu Zhu
- Department of Cardiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
| | - Dachun Xu
- Department of Cardiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
| | - Wenhui Peng
- Department of Cardiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
| | - Ya-Wei Xu
- Department of Cardiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
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Chen MJ, Dixon JE, Manning G. Genomics and evolution of protein phosphatases. Sci Signal 2017; 10:10/474/eaag1796. [DOI: 10.1126/scisignal.aag1796] [Citation(s) in RCA: 110] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Abdel Malik R, Zippel N, Frömel T, Heidler J, Zukunft S, Walzog B, Ansari N, Pampaloni F, Wingert S, Rieger MA, Wittig I, Fisslthaler B, Fleming I. AMP-Activated Protein Kinase α2 in Neutrophils Regulates Vascular Repair via Hypoxia-Inducible Factor-1α and a Network of Proteins Affecting Metabolism and Apoptosis. Circ Res 2016; 120:99-109. [PMID: 27777247 PMCID: PMC5213742 DOI: 10.1161/circresaha.116.309937] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 10/17/2016] [Accepted: 10/21/2016] [Indexed: 12/21/2022]
Abstract
RATIONALE The AMP-activated protein kinase (AMPK) is stimulated by hypoxia, and although the AMPKα1 catalytic subunit has been implicated in angiogenesis, little is known about the role played by the AMPKα2 subunit in vascular repair. OBJECTIVE To determine the role of the AMPKα2 subunit in vascular repair. METHODS AND RESULTS Recovery of blood flow after femoral artery ligation was impaired (>80%) in AMPKα2-/- versus wild-type mice, a phenotype reproduced in mice lacking AMPKα2 in myeloid cells (AMPKα2ΔMC). Three days after ligation, neutrophil infiltration into ischemic limbs of AMPKα2ΔMC mice was lower than that in wild-type mice despite being higher after 24 hours. Neutrophil survival in ischemic tissue is required to attract monocytes that contribute to the angiogenic response. Indeed, apoptosis was increased in hypoxic neutrophils from AMPKα2ΔMC mice, fewer monocytes were recruited, and gene array analysis revealed attenuated expression of proangiogenic proteins in ischemic AMPKα2ΔMC hindlimbs. Many angiogenic growth factors are regulated by hypoxia-inducible factor, and hypoxia-inducible factor-1α induction was attenuated in AMPKα2-deficient cells and accompanied by its enhanced hydroxylation. Also, fewer proteins were regulated by hypoxia in neutrophils from AMPKα2ΔMC mice. Mechanistically, isocitrate dehydrogenase expression and the production of α-ketoglutarate, which negatively regulate hypoxia-inducible factor-1α stability, were attenuated in neutrophils from wild-type mice but remained elevated in cells from AMPKα2ΔMC mice. CONCLUSIONS AMPKα2 regulates α-ketoglutarate generation, hypoxia-inducible factor-1α stability, and neutrophil survival, which in turn determine further myeloid cell recruitment and repair potential. The activation of AMPKα2 in neutrophils is a decisive event in the initiation of vascular repair after ischemia.
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Affiliation(s)
- Randa Abdel Malik
- From the Institute for Vascular Signaling, Centre for Molecular Medicine (R.A.M., N.Z., T.F., S.Z., B.F., I.F.), Functional Proteomics, SFB 815 Core Unit, Faculty of Medicine (J.H., I.W.), ECCPS Metabolomics Facility, Institute for Vascular Signaling, Centre for Molecular Medicine (S.Z.), Department of Hematology/Oncology (S.W., M.A.R.), and Buchmann Institute for Molecular Life Sciences (N.A., F.P.), Goethe University, Frankfurt am Main, Germany; German Center of Cardiovascular Research (DZHK), Partner site Rhein-Main, Frankfurt am Main, Germany (R.A.M., T.F., J.H., S.Z., B.F., I.F.); and Walter-Brendel-Centre of Experimental Medicine, Department of Cardiovascular Physiology and Pathophysiology, Ludwig Maximilians University, Munich, Germany (B.W.)
| | - Nina Zippel
- From the Institute for Vascular Signaling, Centre for Molecular Medicine (R.A.M., N.Z., T.F., S.Z., B.F., I.F.), Functional Proteomics, SFB 815 Core Unit, Faculty of Medicine (J.H., I.W.), ECCPS Metabolomics Facility, Institute for Vascular Signaling, Centre for Molecular Medicine (S.Z.), Department of Hematology/Oncology (S.W., M.A.R.), and Buchmann Institute for Molecular Life Sciences (N.A., F.P.), Goethe University, Frankfurt am Main, Germany; German Center of Cardiovascular Research (DZHK), Partner site Rhein-Main, Frankfurt am Main, Germany (R.A.M., T.F., J.H., S.Z., B.F., I.F.); and Walter-Brendel-Centre of Experimental Medicine, Department of Cardiovascular Physiology and Pathophysiology, Ludwig Maximilians University, Munich, Germany (B.W.)
| | - Timo Frömel
- From the Institute for Vascular Signaling, Centre for Molecular Medicine (R.A.M., N.Z., T.F., S.Z., B.F., I.F.), Functional Proteomics, SFB 815 Core Unit, Faculty of Medicine (J.H., I.W.), ECCPS Metabolomics Facility, Institute for Vascular Signaling, Centre for Molecular Medicine (S.Z.), Department of Hematology/Oncology (S.W., M.A.R.), and Buchmann Institute for Molecular Life Sciences (N.A., F.P.), Goethe University, Frankfurt am Main, Germany; German Center of Cardiovascular Research (DZHK), Partner site Rhein-Main, Frankfurt am Main, Germany (R.A.M., T.F., J.H., S.Z., B.F., I.F.); and Walter-Brendel-Centre of Experimental Medicine, Department of Cardiovascular Physiology and Pathophysiology, Ludwig Maximilians University, Munich, Germany (B.W.)
| | - Juliana Heidler
- From the Institute for Vascular Signaling, Centre for Molecular Medicine (R.A.M., N.Z., T.F., S.Z., B.F., I.F.), Functional Proteomics, SFB 815 Core Unit, Faculty of Medicine (J.H., I.W.), ECCPS Metabolomics Facility, Institute for Vascular Signaling, Centre for Molecular Medicine (S.Z.), Department of Hematology/Oncology (S.W., M.A.R.), and Buchmann Institute for Molecular Life Sciences (N.A., F.P.), Goethe University, Frankfurt am Main, Germany; German Center of Cardiovascular Research (DZHK), Partner site Rhein-Main, Frankfurt am Main, Germany (R.A.M., T.F., J.H., S.Z., B.F., I.F.); and Walter-Brendel-Centre of Experimental Medicine, Department of Cardiovascular Physiology and Pathophysiology, Ludwig Maximilians University, Munich, Germany (B.W.)
| | - Sven Zukunft
- From the Institute for Vascular Signaling, Centre for Molecular Medicine (R.A.M., N.Z., T.F., S.Z., B.F., I.F.), Functional Proteomics, SFB 815 Core Unit, Faculty of Medicine (J.H., I.W.), ECCPS Metabolomics Facility, Institute for Vascular Signaling, Centre for Molecular Medicine (S.Z.), Department of Hematology/Oncology (S.W., M.A.R.), and Buchmann Institute for Molecular Life Sciences (N.A., F.P.), Goethe University, Frankfurt am Main, Germany; German Center of Cardiovascular Research (DZHK), Partner site Rhein-Main, Frankfurt am Main, Germany (R.A.M., T.F., J.H., S.Z., B.F., I.F.); and Walter-Brendel-Centre of Experimental Medicine, Department of Cardiovascular Physiology and Pathophysiology, Ludwig Maximilians University, Munich, Germany (B.W.)
| | - Barbara Walzog
- From the Institute for Vascular Signaling, Centre for Molecular Medicine (R.A.M., N.Z., T.F., S.Z., B.F., I.F.), Functional Proteomics, SFB 815 Core Unit, Faculty of Medicine (J.H., I.W.), ECCPS Metabolomics Facility, Institute for Vascular Signaling, Centre for Molecular Medicine (S.Z.), Department of Hematology/Oncology (S.W., M.A.R.), and Buchmann Institute for Molecular Life Sciences (N.A., F.P.), Goethe University, Frankfurt am Main, Germany; German Center of Cardiovascular Research (DZHK), Partner site Rhein-Main, Frankfurt am Main, Germany (R.A.M., T.F., J.H., S.Z., B.F., I.F.); and Walter-Brendel-Centre of Experimental Medicine, Department of Cardiovascular Physiology and Pathophysiology, Ludwig Maximilians University, Munich, Germany (B.W.)
| | - Nariman Ansari
- From the Institute for Vascular Signaling, Centre for Molecular Medicine (R.A.M., N.Z., T.F., S.Z., B.F., I.F.), Functional Proteomics, SFB 815 Core Unit, Faculty of Medicine (J.H., I.W.), ECCPS Metabolomics Facility, Institute for Vascular Signaling, Centre for Molecular Medicine (S.Z.), Department of Hematology/Oncology (S.W., M.A.R.), and Buchmann Institute for Molecular Life Sciences (N.A., F.P.), Goethe University, Frankfurt am Main, Germany; German Center of Cardiovascular Research (DZHK), Partner site Rhein-Main, Frankfurt am Main, Germany (R.A.M., T.F., J.H., S.Z., B.F., I.F.); and Walter-Brendel-Centre of Experimental Medicine, Department of Cardiovascular Physiology and Pathophysiology, Ludwig Maximilians University, Munich, Germany (B.W.)
| | - Francesco Pampaloni
- From the Institute for Vascular Signaling, Centre for Molecular Medicine (R.A.M., N.Z., T.F., S.Z., B.F., I.F.), Functional Proteomics, SFB 815 Core Unit, Faculty of Medicine (J.H., I.W.), ECCPS Metabolomics Facility, Institute for Vascular Signaling, Centre for Molecular Medicine (S.Z.), Department of Hematology/Oncology (S.W., M.A.R.), and Buchmann Institute for Molecular Life Sciences (N.A., F.P.), Goethe University, Frankfurt am Main, Germany; German Center of Cardiovascular Research (DZHK), Partner site Rhein-Main, Frankfurt am Main, Germany (R.A.M., T.F., J.H., S.Z., B.F., I.F.); and Walter-Brendel-Centre of Experimental Medicine, Department of Cardiovascular Physiology and Pathophysiology, Ludwig Maximilians University, Munich, Germany (B.W.)
| | - Susanne Wingert
- From the Institute for Vascular Signaling, Centre for Molecular Medicine (R.A.M., N.Z., T.F., S.Z., B.F., I.F.), Functional Proteomics, SFB 815 Core Unit, Faculty of Medicine (J.H., I.W.), ECCPS Metabolomics Facility, Institute for Vascular Signaling, Centre for Molecular Medicine (S.Z.), Department of Hematology/Oncology (S.W., M.A.R.), and Buchmann Institute for Molecular Life Sciences (N.A., F.P.), Goethe University, Frankfurt am Main, Germany; German Center of Cardiovascular Research (DZHK), Partner site Rhein-Main, Frankfurt am Main, Germany (R.A.M., T.F., J.H., S.Z., B.F., I.F.); and Walter-Brendel-Centre of Experimental Medicine, Department of Cardiovascular Physiology and Pathophysiology, Ludwig Maximilians University, Munich, Germany (B.W.)
| | - Michael A Rieger
- From the Institute for Vascular Signaling, Centre for Molecular Medicine (R.A.M., N.Z., T.F., S.Z., B.F., I.F.), Functional Proteomics, SFB 815 Core Unit, Faculty of Medicine (J.H., I.W.), ECCPS Metabolomics Facility, Institute for Vascular Signaling, Centre for Molecular Medicine (S.Z.), Department of Hematology/Oncology (S.W., M.A.R.), and Buchmann Institute for Molecular Life Sciences (N.A., F.P.), Goethe University, Frankfurt am Main, Germany; German Center of Cardiovascular Research (DZHK), Partner site Rhein-Main, Frankfurt am Main, Germany (R.A.M., T.F., J.H., S.Z., B.F., I.F.); and Walter-Brendel-Centre of Experimental Medicine, Department of Cardiovascular Physiology and Pathophysiology, Ludwig Maximilians University, Munich, Germany (B.W.)
| | - Ilka Wittig
- From the Institute for Vascular Signaling, Centre for Molecular Medicine (R.A.M., N.Z., T.F., S.Z., B.F., I.F.), Functional Proteomics, SFB 815 Core Unit, Faculty of Medicine (J.H., I.W.), ECCPS Metabolomics Facility, Institute for Vascular Signaling, Centre for Molecular Medicine (S.Z.), Department of Hematology/Oncology (S.W., M.A.R.), and Buchmann Institute for Molecular Life Sciences (N.A., F.P.), Goethe University, Frankfurt am Main, Germany; German Center of Cardiovascular Research (DZHK), Partner site Rhein-Main, Frankfurt am Main, Germany (R.A.M., T.F., J.H., S.Z., B.F., I.F.); and Walter-Brendel-Centre of Experimental Medicine, Department of Cardiovascular Physiology and Pathophysiology, Ludwig Maximilians University, Munich, Germany (B.W.)
| | - Beate Fisslthaler
- From the Institute for Vascular Signaling, Centre for Molecular Medicine (R.A.M., N.Z., T.F., S.Z., B.F., I.F.), Functional Proteomics, SFB 815 Core Unit, Faculty of Medicine (J.H., I.W.), ECCPS Metabolomics Facility, Institute for Vascular Signaling, Centre for Molecular Medicine (S.Z.), Department of Hematology/Oncology (S.W., M.A.R.), and Buchmann Institute for Molecular Life Sciences (N.A., F.P.), Goethe University, Frankfurt am Main, Germany; German Center of Cardiovascular Research (DZHK), Partner site Rhein-Main, Frankfurt am Main, Germany (R.A.M., T.F., J.H., S.Z., B.F., I.F.); and Walter-Brendel-Centre of Experimental Medicine, Department of Cardiovascular Physiology and Pathophysiology, Ludwig Maximilians University, Munich, Germany (B.W.)
| | - Ingrid Fleming
- From the Institute for Vascular Signaling, Centre for Molecular Medicine (R.A.M., N.Z., T.F., S.Z., B.F., I.F.), Functional Proteomics, SFB 815 Core Unit, Faculty of Medicine (J.H., I.W.), ECCPS Metabolomics Facility, Institute for Vascular Signaling, Centre for Molecular Medicine (S.Z.), Department of Hematology/Oncology (S.W., M.A.R.), and Buchmann Institute for Molecular Life Sciences (N.A., F.P.), Goethe University, Frankfurt am Main, Germany; German Center of Cardiovascular Research (DZHK), Partner site Rhein-Main, Frankfurt am Main, Germany (R.A.M., T.F., J.H., S.Z., B.F., I.F.); and Walter-Brendel-Centre of Experimental Medicine, Department of Cardiovascular Physiology and Pathophysiology, Ludwig Maximilians University, Munich, Germany (B.W.).
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Demishtein-Zohary K, Azem A. The TIM23 mitochondrial protein import complex: function and dysfunction. Cell Tissue Res 2016; 367:33-41. [DOI: 10.1007/s00441-016-2486-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 08/05/2016] [Indexed: 01/16/2023]
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30
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Novoderezhkina EA, Zhivotovsky BD, Gogvadze VG. Induction of unspecific permeabilization of mitochondrial membrane and its role in cell death. Mol Biol 2016. [DOI: 10.1134/s0026893316010167] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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31
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Loss of TIM50 suppresses proliferation and induces apoptosis in breast cancer. Tumour Biol 2015; 37:1279-87. [DOI: 10.1007/s13277-015-3878-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 07/30/2015] [Indexed: 10/23/2022] Open
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Thomas JL, Bose HS. Regulation of human 3-beta-hydroxysteroid dehydrogenase type-2 (3βHSD2) by molecular chaperones and the mitochondrial environment affects steroidogenesis. J Steroid Biochem Mol Biol 2015; 151:74-84. [PMID: 25448736 DOI: 10.1016/j.jsbmb.2014.11.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 10/09/2014] [Accepted: 11/19/2014] [Indexed: 10/24/2022]
Abstract
Human 3-β-hydroxysteroid dehydrogenase/isomerase types 1 and 2 (3βHSD1 and 3βHSD2, respectively) are expressed in a tissue-specific pattern by different genes. Site-directed mutagenesis studies have confirmed the function of the catalytic amino acids (Tyr154, Lys 158, Ser124 in both isoenzymes), substrate/inhibitor isoform-specific residues (His156 and Arg195 in 3βHSD1) and cofactor binding residues (Asp36 provides NAD(+) specificity in both isoenzymes). However, detailed analysis of isoform-specific organelle localization and characterization is difficult due to the 93% amino acid identity between the two isoforms. With recent advances in the knowledge of mitochondrial architecture and localization of the various translocases, our laboratory has studied the mechanisms regulating mitochondrial 3βHSD2 localization. The mitochondrial N-terminal leader sequence of 3βHSD2 directs its entry into the mitochondria where it is localized to the intermembrane space (IMS). Unlike other mitochondrial proteins, the N-terminal signal sequence of 3βHSD2 is not cleaved upon mitochondrial import. 3βHSD2 interacts with the mitochondrial translocase, Tim50, to regulate progesterone and androstenedione formation. Our studies suggest that its activity at the IMS is facilitated in a partially unfolded "molten globule" conformation by the proton pump between the matrix and IMS. The unfolded protein is refolded by the mitochondrial chaperones. The protons at the IMS are absorbed by the lipid vesicles, to maintain the proton pump and recycle 3βHSD2. As a result, one molecule of 3βHSD2 may participate in multiple catalytic reactions. In summary, the steroidogenic cell recycles 3βHSD2 to catalyze the reactions needed to produce androstenedione, progesterone and 17α-hydroxyprogesterone on demand in coordination with the mitochondrial translocase, Tim50. This article is part of a Special Issue entitled 'Steroid/Sterol signaling'.
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Affiliation(s)
- James L Thomas
- Division of Basic Medical Sciences, Mercer University School of Medicine, Macon, GA 31207, USA
| | - Himangshu S Bose
- Departments of Biochemistry, Biomedical Sciences, Mercer University School of Medicine, Savannah, GA 31404, USA; Memorial University Medical Center, Anderson Cancer Institute, Savannah, GA 31404, USA.
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Fullerton M, Singha UK, Duncan M, Chaudhuri M. Down regulation of Tim50 in Trypanosoma brucei increases tolerance to oxidative stress. Mol Biochem Parasitol 2015; 199:9-18. [PMID: 25791316 DOI: 10.1016/j.molbiopara.2015.03.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Revised: 03/06/2015] [Accepted: 03/08/2015] [Indexed: 12/15/2022]
Abstract
Trypanosoma brucei, the causative agent for African trypanosomiasis, possesses a single mitochondrion that imports hundreds of proteins from the cytosol. However, the parasite only possesses a few homologs of the canonical protein translocases found in fungi and animals. We recently characterized a homolog of the translocase of the mitochondrial inner membrane, Tim50, in T. brucei. TbTim50 knockdown (KD) moderately reduced cell growth, decreased the mitochondrial membrane potential, and inhibited import of proteins into mitochondria. In contrast to Tim50 KD, we show here that TbTim50 overexpression (OE) increased the mitochondrial membrane potential as well as increased the production of cellular reactive oxygen species (ROS). Therefore, TbTim50 OE also inhibits cell growth. In addition, TbTim50 OE and KD cells showed different responses upon treatment with H2O2. Surprisingly, TbTim50 KD cells showed a greater tolerance to oxidative stress. Further analysis revealed that TbTim50 KD inhibits transition of cells from an early to late apoptotic stage upon exposure to increasing concentrations of H2O2. On the other hand TbTim50 OE caused cells to be in a pro-apoptotic stage and thus they underwent increased cell death upon H2O2 treatment. However, externally added H2O2 similarly increased the levels of cellular ROS and decreased the mitochondrial membrane potential in both cell types, indicating that tolerance to ROS is mediated through induction of the stress-response pathway due to TbTim50 KD. Together, these results suggest that TbTim50 acts as a stress sensor and that down regulation of Tim50 could be a survival mechanism for T. brucei exposed to oxidative stress.
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Affiliation(s)
- Marjorie Fullerton
- Department of Microbiology and Immunology, Meharry Medical College, Nashville, TN, USA
| | - Ujjal K Singha
- Department of Microbiology and Immunology, Meharry Medical College, Nashville, TN, USA
| | | | - Minu Chaudhuri
- Department of Microbiology and Immunology, Meharry Medical College, Nashville, TN, USA.
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Bleier L, Wittig I, Heide H, Steger M, Brandt U, Dröse S. Generator-specific targets of mitochondrial reactive oxygen species. Free Radic Biol Med 2015; 78:1-10. [PMID: 25451644 DOI: 10.1016/j.freeradbiomed.2014.10.511] [Citation(s) in RCA: 123] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Revised: 10/13/2014] [Accepted: 10/14/2014] [Indexed: 10/24/2022]
Abstract
To understand the role of reactive oxygen species (ROS) in oxidative stress and redox signaling it is necessary to link their site of generation to the oxidative modification of specific targets. Here we have studied the selective modification of protein thiols by mitochondrial ROS that have been implicated as deleterious agents in a number of degenerative diseases and in the process of biological aging, but also as important players in cellular signal transduction. We hypothesized that this bipartite role might be based on different generator sites for "signaling" and "damaging" ROS and a directed release into different mitochondrial compartments. Because two main mitochondrial ROS generators, complex I (NADH:ubiquinone oxidoreductase) and complex III (ubiquinol:cytochrome c oxidoreductase; cytochrome bc1 complex), are known to predominantly release superoxide and the derived hydrogen peroxide (H2O2) into the mitochondrial matrix and the intermembrane space, respectively, we investigated whether these ROS generators selectively oxidize specific protein thiols. We used redox fluorescence difference gel electrophoresis analysis to identify redox-sensitive targets in the mitochondrial proteome of intact rat heart mitochondria. We observed that the modified target proteins were distinctly different when complex I or complex III was employed as the source of ROS. These proteins are potential targets involved in mitochondrial redox signaling and may serve as biomarkers to study the generator-dependent dual role of mitochondrial ROS in redox signaling and oxidative stress.
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Affiliation(s)
- Lea Bleier
- Molecular Bioenergetics Group, Goethe-University, D-60590 Frankfurt am Main, Germany
| | - Ilka Wittig
- Molecular Bioenergetics Group, Goethe-University, D-60590 Frankfurt am Main, Germany; Functional Proteomics, SFB815 Core Unit, Medical School, Goethe-University, D-60590 Frankfurt am Main, Germany
| | - Heinrich Heide
- Molecular Bioenergetics Group, Goethe-University, D-60590 Frankfurt am Main, Germany
| | - Mirco Steger
- Molecular Bioenergetics Group, Goethe-University, D-60590 Frankfurt am Main, Germany
| | - Ulrich Brandt
- Molecular Bioenergetics Group, Goethe-University, D-60590 Frankfurt am Main, Germany; Cluster of Excellence Frankfurt "Macromolecular Complexes," Goethe-University, D-60590 Frankfurt am Main, Germany; Radboud University Medical Center, Nijmegen Center for Mitochondrial Disorders, 6500 GA Nijmegen, The Netherlands
| | - Stefan Dröse
- Molecular Bioenergetics Group, Goethe-University, D-60590 Frankfurt am Main, Germany; Clinic of Anaesthesiology, Intensive Care Medicine and Pain Therapy, Goethe-University Hospital, Frankfurt am Main, Germany.
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Mitochondrial protein translocases for survival and wellbeing. FEBS Lett 2014; 588:2484-95. [DOI: 10.1016/j.febslet.2014.05.028] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 05/15/2014] [Accepted: 05/15/2014] [Indexed: 11/20/2022]
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Candas D, Li JJ. MnSOD in oxidative stress response-potential regulation via mitochondrial protein influx. Antioxid Redox Signal 2014; 20:1599-617. [PMID: 23581847 PMCID: PMC3942709 DOI: 10.1089/ars.2013.5305] [Citation(s) in RCA: 462] [Impact Index Per Article: 46.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
SIGNIFICANCE The mitochondrial antioxidant manganese superoxide dismutase (MnSOD) is encoded by genomic DNA and its dismutase function is fully activated in the mitochondria to detoxify free radical O2(•-) generated by mitochondrial respiration. Accumulating evidence shows an extensive communication between the mitochondria and cytoplasm under oxidative stress. Not only is the MnSOD gene upregulated by oxidative stress, but MnSOD activity can be enhanced via the mitochondrial protein influx (MPI). RECENT ADVANCES A cluster of MPI containing cytoplasmic/nuclear proteins, such as cyclins, cyclin-dependent kinases, and p53 interact with and alter MnSOD activity. These proteins modulate MnSOD superoxide scavenging activity via post-translational modifications in the mitochondria. In addition to well-established pathways in gene expression, recent findings suggest that MnSOD enzymatic activity can also be enhanced by phosphorylation of specific motifs in mitochondria. This review attempts to discuss the pre- and post-translational regulation of MnSOD, and how these modifications alter MnSOD activity, which induces a cell adaptive response to oxidative stress. CRITICAL ISSUES MnSOD is biologically significant to aerobic cells. Its role in protecting the cells against the deleterious effects of reactive oxygen species is evident. However, the exact network of MnSOD-associated cellular adaptive reaction to oxidative stress and its post-translational modifications, especially its enzymatic enhancement via phosphorylation, is not yet fully understood. FUTURE DIRECTIONS The broad discussion of the multiple aspects of MnSOD regulation, including gene expression, protein modifications, and enzymatic activity, will shed light onto the unknown mechanisms that govern the prosurvival networks involved in cellular and mitochondrial adaptive response to genotoxic environment.
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Affiliation(s)
- Demet Candas
- 1 Department of Radiation Oncology, University of California Davis , Sacramento, California
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Veldhoen N, Propper CR, Helbing CC. Enabling comparative gene expression studies of thyroid hormone action through the development of a flexible real-time quantitative PCR assay for use across multiple anuran indicator and sentinel species. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2014; 148:162-173. [PMID: 24503578 DOI: 10.1016/j.aquatox.2014.01.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Revised: 01/07/2014] [Accepted: 01/10/2014] [Indexed: 06/03/2023]
Abstract
Studies performed across diverse frog species have made substantial contributions to our understanding of basic vertebrate development and the natural or anthropogenic environmental factors impacting sensitive life stages. Because, anurans are developmental models, provide ecosystems services, and act as sentinels for the identification of environmental chemical contaminants that interfere with thyroid hormone (TH) action during postembryonic development, there is demand for flexible assessment techniques that can be applied to multiple species. As part of the "thyroid assays across indicator and sentinel species" (TAXISS) initiative, we have designed and validated a series of cross-species real time quantitative PCR (qPCR) primer sets that provide information on transcriptome components in evolutionarily distant anurans. Validation for fifteen gene transcripts involved a rigorous three-tiered quality control within tissue/development-specific contexts. Assay performance was confirmed on multiple tissues (tail fin, liver, brain, and intestine) of Rana catesbeiana and Xenopus laevis tadpoles enabling comparisons between tissues and generation of response profiles to exogenous TH. This revealed notable differences in TH-responsive gene transcripts including thra, thrb, thibz, klf9, col1a2, fn1, plp1, mmp2, timm50, otc, and dio2, suggesting differential regulation and susceptibility to contaminant effects. Evidence for the applicability of the TAXISS anuran qPCR assay across seven other species is also provided with five frog families represented and its utility in defining genome structure was demonstrated. This novel validated approach will enable meaningful comparative studies between frog species and aid in extending knowledge of developmental regulatory pathways and the impact of environmental factors on TH signaling in frog species for which little or no genetic information is currently available.
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Affiliation(s)
- Nik Veldhoen
- Department of Biochemistry and Microbiology, University of Victoria, PO Box 3055, STN CSC, Victoria, BC, Canada V8W 2Y2
| | - Catherine R Propper
- Department of Biological Sciences, Northern Arizona University, S. Beaver St., Flagstaff, AZ 86011, USA
| | - Caren C Helbing
- Department of Biochemistry and Microbiology, University of Victoria, PO Box 3055, STN CSC, Victoria, BC, Canada V8W 2Y2.
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Tagliati F, Gagliano T, Gentilin E, Minoia M, Molè D, delgi Uberti EC, Zatelli MC. Magmas overexpression inhibits staurosporine induced apoptosis in rat pituitary adenoma cell lines. PLoS One 2013; 8:e75194. [PMID: 24069394 PMCID: PMC3775776 DOI: 10.1371/journal.pone.0075194] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Accepted: 08/14/2013] [Indexed: 12/22/2022] Open
Abstract
Magmas is a nuclear gene that encodes for the mitochondrial import inner membrane translocase subunit Tim16. Magmas is overexpressed in the majority of human pituitary adenomas and in a mouse ACTH-secreting pituitary adenoma cell line. Here we report that Magmas is highly expressed in two out of four rat pituitary adenoma cell lines and its expression levels inversely correlate to the extent of cellular response to staurosporine in terms of apoptosis activation and cell viability. Magmas over-expression in rat GH/PRL-secreting pituitary adenoma GH4C1 cells leads to an increase in cell viability and to a reduction in staurosporine-induced apoptosis and DNA fragmentation, in parallel with the increase in Magmas protein expression. These results indicate that Magmas plays a pivotal role in response to pro-apoptotic stimuli and confirm and extend the finding that Magmas protects pituitary cells from staurosporine-induced apoptosis, suggesting its possible involvement in pituitary adenoma development.
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Affiliation(s)
- Federico Tagliati
- Section of Endocrinology, Department of Medical Sciences, University of Ferrara, Ferrara, Italy
| | - Teresa Gagliano
- Section of Endocrinology, Department of Medical Sciences, University of Ferrara, Ferrara, Italy
| | - Erica Gentilin
- Section of Endocrinology, Department of Medical Sciences, University of Ferrara, Ferrara, Italy
- Laboratorio in rete del Tecnopolo “Tecnologie delle terapie avanzate” (LTTA) of the University of Ferrara, Ferrara, Italy
| | - Mariella Minoia
- Section of Endocrinology, Department of Medical Sciences, University of Ferrara, Ferrara, Italy
| | - Daniela Molè
- Section of Endocrinology, Department of Medical Sciences, University of Ferrara, Ferrara, Italy
| | - Ettore C. delgi Uberti
- Section of Endocrinology, Department of Medical Sciences, University of Ferrara, Ferrara, Italy
- Laboratorio in rete del Tecnopolo “Tecnologie delle terapie avanzate” (LTTA) of the University of Ferrara, Ferrara, Italy
| | - Maria Chiara Zatelli
- Section of Endocrinology, Department of Medical Sciences, University of Ferrara, Ferrara, Italy
- Laboratorio in rete del Tecnopolo “Tecnologie delle terapie avanzate” (LTTA) of the University of Ferrara, Ferrara, Italy
- * E-mail:
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Duncan MR, Fullerton M, Chaudhuri M. Tim50 in Trypanosoma brucei possesses a dual specificity phosphatase activity and is critical for mitochondrial protein import. J Biol Chem 2012; 288:3184-97. [PMID: 23212919 DOI: 10.1074/jbc.m112.436378] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
In eukaryotes, proteins are imported into mitochondria via multiprotein translocases of the mitochondrial outer and inner membranes, TOM and TIM, respectively. Trypanosoma brucei, a hemoflagellated parasitic protozoan and the causative agent of African trypanosomiasis, imports about a thousand proteins into the mitochondrion; however, the mitochondrial protein import machinery in this organism is largely unidentified. Here, we characterized a homolog of Tim50 that is localized in the mitochondrial membrane in T. brucei. Similar to Tim50 proteins from fungi and mammals, Tim50 in T. brucei (TbTim50) possesses a mitochondrial targeting signal at its N terminus and a C-terminal domain phosphatase motif at its C terminus. Knockdown of TbTim50 reduced cell growth and inhibited import of proteins that contain N-terminal targeting signals. Co-immunoprecipitation analysis revealed that TbTim50 interacts with TbTim17. Unlike its fungal counterpart but similar to the human homolog of Tim50, recombinant TbTim50 possesses a dual specificity phosphatase activity with a greater affinity for protein tyrosine phosphate than for protein serine/threonine phosphate. Mutation of the aspartic acid residues to alanine in the C-terminal domain phosphatase motif (242)DXDX(V/T)(246) abolished activity for both type of substrates. TbTim50 knockdown increased and its overexpression decreased the level of voltage-dependent anion channel (VDAC). However, the VDAC level was unaltered when the phosphatase-inactive mutant of TbTim50 was overexpressed, suggesting that the phosphatase activity of TbTim50 plays a role in regulation of VDAC expression. In contrast, phosphatase activity of the TbTim50 is required neither for mitochondrial protein import nor for its interaction with TbTim17. Overall, our results show that TbTim50 plays additional roles in mitochondrial activities besides preprotein translocation.
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Affiliation(s)
- Melanie R Duncan
- Department of Microbiology and Immunology, Meharry Medical College, Nashville, Tennessee 37208, USA
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40
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Interaction of divalent metal ions with human translocase of inner membrane of mitochondria Tim50. Biochem Biophys Res Commun 2012; 428:365-70. [DOI: 10.1016/j.bbrc.2012.10.060] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2012] [Accepted: 10/15/2012] [Indexed: 11/21/2022]
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Sun Z, Biela LM, Hamilton KL, Reardon KF. Concentration-dependent effects of the soy phytoestrogen genistein on the proteome of cultured cardiomyocytes. J Proteomics 2012; 75:3592-604. [PMID: 22521270 DOI: 10.1016/j.jprot.2012.04.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Revised: 03/29/2012] [Accepted: 04/02/2012] [Indexed: 12/23/2022]
Abstract
The soy-derived phytoestrogen genistein (GEN) has received attention for its potential benefits on the cardiovascular system by providing direct protection to cardiomyocytes against pathophysiological stresses. Here, we employed a proteomic approach to study the concentration-dependent effects of GEN treatments on cardiomyocytes. Cultured HL-1 cardiomyocytes were treated with low (1μM) and high (50μM) concentrations of GEN. Proteins were pre-fractionated by sequential hydrophilic/hydrophobic extraction and both protein fractions from each treatment group were separated by 2D gel electrophoresis (2DE). Overall, approximately 2,700 spots were visualized on the 2D gels. Thirty-nine and 99 spots changed in volume relative to controls (p<0.05) following the low- and high-concentration GEN treatments, respectively. From these spots, 25 and 62 protein species were identified by ESI-MS/MS and Mascot database searching, respectively. Identified proteins were further categorized according to their functions and possible links to cardioprotection were discussed. MetaCore gene ontology analysis suggested that 1μM GEN significantly impacted the anti-apoptosis process, and that both the low and high concentrations of GEN influenced the glucose catabolic process and regulation of ATPase activity. This proteomics study provides the first global insight into the molecular events triggered by GEN treatment in cardiomyocytes.
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Affiliation(s)
- Zeyu Sun
- Department of Chemical and Biological Engineering, Colorado State University, Fort Collins, CO 80523-1370, USA
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Zhang Y, Deng H, Zhao Q, Li SJ. Interaction of Presequence with Human Translocase of the Inner Membrane of Mitochondria Tim50. J Phys Chem B 2012; 116:2990-8. [DOI: 10.1021/jp2108279] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yongqiang Zhang
- The Key Laboratory of Bioactive Materials, Ministry of Education, School of Physics Science, Nankai University, Tianjin 300071, P. R. China
- Basic Department, Bengbu Automobile Sergeant School of the People’s Liberation Army, Bengbu 233011, P. R. China
| | - Honghua Deng
- The Key Laboratory of Bioactive Materials, Ministry of Education, School of Physics Science, Nankai University, Tianjin 300071, P. R. China
| | - Qing Zhao
- The Key Laboratory of Bioactive Materials, Ministry of Education, School of Physics Science, Nankai University, Tianjin 300071, P. R. China
| | - Shu Jie Li
- The Key Laboratory of Bioactive Materials, Ministry of Education, School of Physics Science, Nankai University, Tianjin 300071, P. R. China
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Kumar S, Yoshizumi T, Hongo H, Yoneda A, Hara H, Hamasaki H, Takahashi N, Nagata N, Shimada H, Matsui M. Arabidopsis mitochondrial protein TIM50 affects hypocotyl cell elongation through intracellular ATP level. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2012; 183:212-7. [PMID: 22195596 DOI: 10.1016/j.plantsci.2011.08.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Revised: 08/31/2011] [Accepted: 08/31/2011] [Indexed: 05/08/2023]
Abstract
The plant hypocotyl is an excellent model for the analysis of cell elongation. We have characterized a knockout mutant of the Arabidopsis TIM50 gene that showed a reduction in the hypocotyls length of etiolated seedlings. We also found that a knockout of TIM50 caused enlargement and deformation of the mitochondrial structure and a reduction in intracellular ATP levels. TIM50 is a component of the mitochondrial TIM23 inner membrane protein complex and is involved in the import of mitochondrial proteins. The short hypocotyl phenotype was recovered by the addition of Compound C, an inhibitor of AMPK. Thus, the mitochondrial ATP level controls cell elongation in Arabidopsis hypocotyls through possible signaling via AMPK.
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Affiliation(s)
- Shailesh Kumar
- Plant Synthetic Genomics Research Division, Kihara Institute for Biological Research, Yokohama City University, 641-12 Maioka-cho, Totsuka-ku, Yokohama 244-0813, Japan
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Pawlak KJ, Prasad M, Thomas JL, Whittal RM, Bose HS. Inner mitochondrial translocase Tim50 interacts with 3β-hydroxysteroid dehydrogenase type 2 to regulate adrenal and gonadal steroidogenesis. J Biol Chem 2011; 286:39130-40. [PMID: 21930695 DOI: 10.1074/jbc.m111.290031] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In the adrenals, testes, and ovaries, 3β-hydroxysteroid dehydrogenase type 2 (3βHSD2) catalyzes the conversion of pregnenolone to progesterone and dehydroepiandrostenedione to androstenedione. Alterations in this pathway can have deleterious effects, including sexual development impairment, spontaneous abortion, and breast cancer. 3βHSD2, synthesized in the cytosol, is imported into the inner mitochondrial membrane (IMM) by translocases. Steroidogenesis requires that 3βHSD2 acts as both a dehydrogenase and isomerase. To achieve this dual functionality, 3βHSD2 must undergo a conformational change; however, what triggers that change remains unknown. We propose that 3βHSD2 associates with IMM or outer mitochondrial membrane translocases facing the intermembrane space (IMS) and that this interaction promotes the conformational change needed for full activity. Fractionation assays demonstrate that 3βHSD2 associated with the IMM but did not integrate into the membrane. Through mass spectrometry and Western blotting of mitochondrial complexes and density gradient ultracentrifugation, we show that that 3βHSD2 formed a transient association with the translocases Tim50 and Tom22 and with Tim23. This association occurred primarily through the interaction of Tim50 with the N terminus of 3βHSD2 and contributed to enzymatic activity. Tim50 knockdown inhibited catalysis of dehydroepiandrostenedione to androstenedione and pregnenolone to progesterone. Although Tim50 knockdown decreased 3βHSD2 expression, restoration of expression via proteasome and protease inhibition did not rescue activity. In addition, protein fingerprinting and CD spectroscopy reveal the flexibility of 3βHSD2, a necessary characteristic for forming multiple associations. In summary, Tim50 regulates 3βHSD2 expression and activity, representing a new role for translocases in steroidogenesis.
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Affiliation(s)
- Kevin J Pawlak
- Mercer University School of Medicine, Savannah, Georgia 31404, USA
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Zhang Y, Xu Y, Zhao Q, Ji Z, Li Q, Li SJ. Expression and structural characterization of human translocase of inner membrane of mitochondria Tim50. Protein Expr Purif 2011; 80:130-7. [PMID: 21742040 DOI: 10.1016/j.pep.2011.06.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Revised: 06/17/2011] [Accepted: 06/21/2011] [Indexed: 11/17/2022]
Abstract
The preprotein translocase of the inner membrane of mitochondria (TIM23 complex) is the main entry gate for proteins of the matrix and the inner membrane. Tim50 is a major receptor in TIM23 complex, which spans the inner membrane with a single transmembrane segment and exposes a large hydrophilic domain in the intermembrane space. In this study, we expressed and purified the intermembrane space (IMS) domain of human Tim50 (Tim50(IMS)), and investigated its structural characteristics and assembly behaviors. The far-UV CD spectra of Tim50(IMS) in native and denatured states revealed that the protein has a significantly folded secondary structure consisted of α-helixes and β-sheets. Size exclusion chromatography showed that Tim50(IMS) is a monomer. Furthermore, the results showed, by intrinsic fluorescence, ANS binding, fluorescence anisotropy and fluorescence quenching, that Tim50(IMS) forms a compact structure in the range of pH 8.0-5.0; and it is more compact at pH 8.0 than pH 7.0; when pH decreases below 5.0, the protein is gradually denatured.
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Affiliation(s)
- Yongqiang Zhang
- The Key Laboratory of Bioactive Materials, Ministry of Education, School of Physics Science, Nankai University, Tianjin 300071, PR China
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Sankala H, Vaughan C, Wang J, Deb S, Graves PR. Upregulation of the mitochondrial transport protein, Tim50, by mutant p53 contributes to cell growth and chemoresistance. Arch Biochem Biophys 2011; 512:52-60. [PMID: 21621504 DOI: 10.1016/j.abb.2011.05.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2011] [Revised: 04/17/2011] [Accepted: 05/14/2011] [Indexed: 12/01/2022]
Abstract
The p53 gene is one of the most frequently mutated genes in human cancer. Some p53 mutations impart additional functions that promote oncogenesis. To investigate how these p53 mutants function, a proteomic analysis was performed. The protein, translocator of the inner mitochondrial membrane 50 (Tim50), was upregulated in a non-small cell lung carcinoma cell line (H1299) that expressed the p53 mutants R175H and R273H compared to cells lacking p53. Tim50 was also elevated in the breast cancer cell lines MDA-MB-468 and SK-BR-3, that endogenously express the p53 mutants R175H and R273H, respectively, compared to MCF-10A. The p53 mutants R175H and R273H, but not WT p53, upregulated the expression of a Tim50 promoter construct and chromatin immunoprecipitation (ChIP) analysis indicated increased histone acetylation and increased interaction of the transcription factors Ets-1, CREB and CREB-binding protein (CBP) with the Tim50 promoter in the presence of mutant p53. Finally, reduction of Tim50 expression reduced the growth rate and chemoresistance of cells harboring mutant p53 but had no effect upon cells lacking p53. Taken together, these findings identify the Tim50 gene as a transcriptional target of mutant p53 and suggest a novel mechanism by which p53 mutants enhance cell growth and chemoresistance.
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Affiliation(s)
- Heidi Sankala
- Department of Radiation Oncology, Massey Cancer Center, Virginia Commonwealth University, Richmond, VA 23298-0058, USA
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Curado S, Ober EA, Walsh S, Cortes-Hernandez P, Verkade H, Koehler CM, Stainier DYR. The mitochondrial import gene tomm22 is specifically required for hepatocyte survival and provides a liver regeneration model. Dis Model Mech 2010; 3:486-95. [PMID: 20483998 DOI: 10.1242/dmm.004390] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Understanding liver development should lead to greater insights into liver diseases and improve therapeutic strategies. In a forward genetic screen for genes regulating liver development in zebrafish, we identified a mutant--oliver--that exhibits liver-specific defects. In oliver mutants, the liver is specified, bile ducts form and hepatocytes differentiate. However, the hepatocytes die shortly after their differentiation, and thus the resulting mutant liver consists mainly of biliary tissue. We identified a mutation in the gene encoding translocase of the outer mitochondrial membrane 22 (Tomm22) as responsible for this phenotype. Mutations in tomm genes have been associated with mitochondrial dysfunction, but most studies on the effect of defective mitochondrial protein translocation have been carried out in cultured cells or unicellular organisms. Therefore, the tomm22 mutant represents an important vertebrate genetic model to study mitochondrial biology and hepatic mitochondrial diseases. We further found that the temporary knockdown of Tomm22 levels by morpholino antisense oligonucleotides causes a specific hepatocyte degeneration phenotype that is reversible: new hepatocytes repopulate the liver as Tomm22 recovers to wild-type levels. The specificity and reversibility of hepatocyte ablation after temporary knockdown of Tomm22 provides an additional model to study liver regeneration, under conditions where most hepatocytes have died. We used this regeneration model to analyze the signaling commonalities between hepatocyte development and regeneration.
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Affiliation(s)
- Silvia Curado
- Department of Biochemistry and Biophysics, Programs in Developmental Biology, Genetics and Human Genetics, University of California-San Francisco, 1550 Fourth Street, San Francisco, CA 94158-2324, USA.
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48
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Nam HW. GRA proteins of Toxoplasma gondii: maintenance of host-parasite interactions across the parasitophorous vacuolar membrane. THE KOREAN JOURNAL OF PARASITOLOGY 2010; 47 Suppl:S29-37. [PMID: 19885333 DOI: 10.3347/kjp.2009.47.s.s29] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2009] [Revised: 09/28/2009] [Accepted: 09/28/2009] [Indexed: 01/23/2023]
Abstract
The dense granule of Toxoplasma gondii is a secretory vesicular organelle of which the proteins participate in the modification of the parasitophorous vacuole (PV) and PV membrane for the maintenance of intracellular parasitism in almost all nucleated host cells. In this review, the archives on the research of GRA proteins are reviewed on the foci of finding GRA proteins, characterizing molecular aspects, usefulness in diagnostic antigen, and vaccine trials in addition to some functions in host-parasite interactions.
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Affiliation(s)
- Ho-Woo Nam
- Department of Parasitology, College of Medicine, The Catholic University of Korea, Seoul 137-701, Korea.
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Transcriptional and post-transcriptional regulation of mitochondrial biogenesis in skeletal muscle: effects of exercise and aging. Biochim Biophys Acta Gen Subj 2009; 1800:223-34. [PMID: 19682549 DOI: 10.1016/j.bbagen.2009.07.031] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2009] [Revised: 07/27/2009] [Accepted: 07/30/2009] [Indexed: 12/18/2022]
Abstract
Acute contractile activity of skeletal muscle initiates the activation of signaling kinases. This promotes the phosphorylation of transcription factors, leading to enhanced DNA binding and transcriptional activation and/or repression. The mRNA products of nuclear genes encoding mitochondrial proteins are translated in the cytosol and imported into pre-existing mitochondria. When contractile activity is repeated, the recapitulation of these cellular events progressively leads to an expansion of the mitochondrial reticulum within muscle. This has physiologically relevant health benefit, including enhanced lipid metabolism and reduced muscle fatigability. In aging skeletal muscle, the response to contractile activity appears to be attenuated, suggesting that a greater contractile stimulus is required to attain a similar phenotype adaptation. This review summarizes our current understanding of the effects of exercise on the gene expression pathway leading to organelle biogenesis in muscle.
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Cecconi D, Donadelli M, Dalla Pozza E, Rinalducci S, Zolla L, Scupoli MT, Righetti PG, Scarpa A, Palmieri M. Synergistic effect of trichostatin A and 5-aza-2′-deoxycytidine on growth inhibition of pancreatic endocrine tumour cell lines: A proteomic study. Proteomics 2009; 9:1952-66. [DOI: 10.1002/pmic.200701089] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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