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Vyas PM, Tomamichel WJ, Pride PM, Babbey CM, Wang Q, Mercier J, Martin EM, Payne RM. A TAT-frataxin fusion protein increases lifespan and cardiac function in a conditional Friedreich's ataxia mouse model. Hum Mol Genet 2012; 21:1230-47. [PMID: 22113996 PMCID: PMC3284115 DOI: 10.1093/hmg/ddr554] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Accepted: 11/21/2011] [Indexed: 11/14/2022] Open
Abstract
Friedreich's ataxia (FRDA) is the most common inherited human ataxia and results from a deficiency of the mitochondrial protein, frataxin (FXN), which is encoded in the nucleus. This deficiency is associated with an iron-sulfur (Fe-S) cluster enzyme deficit leading to progressive ataxia and a frequently fatal cardiomyopathy. There is no cure. To determine whether exogenous replacement of the missing FXN protein in mitochondria would repair the defect, we used the transactivator of transcription (TAT) protein transduction domain to deliver human FXN protein to mitochondria in both cultured patient cells and a severe mouse model of FRDA. A TAT-FXN fusion protein bound iron in vitro, transduced into mitochondria of FRDA deficient fibroblasts and reduced caspase-3 activation in response to an exogenous iron-oxidant stress. Injection of TAT-FXN protein into mice with a conditional loss of FXN increased their growth velocity and mean lifespan by 53% increased their mean heart rate and cardiac output, increased activity of aconitase and reversed abnormal mitochondrial proliferation and ultrastructure in heart. These results show that a cell-penetrant peptide is capable of delivering a functional mitochondrial protein in vivo to rescue a very severe disease phenotype, and present the possibility of TAT-FXN as a protein replacement therapy.
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Affiliation(s)
- Piyush M. Vyas
- Riley Heart Research Center, Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Wendy J. Tomamichel
- Riley Heart Research Center, Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - P. Melanie Pride
- Riley Heart Research Center, Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Clifford M. Babbey
- Riley Heart Research Center, Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Qiujuan Wang
- Riley Heart Research Center, Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Jennifer Mercier
- Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
| | - Elizabeth M. Martin
- Riley Heart Research Center, Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - R. Mark Payne
- Riley Heart Research Center, Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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Rayapureddi JP, Tomamichel WJ, Walton ST, Payne RM. TAT fusion protein transduction into isolated mitochondria is accelerated by sodium channel inhibitors. Biochemistry 2011; 49:9470-9. [PMID: 20925426 DOI: 10.1021/bi101057v] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Stringent control of ion and protein transport across the mitochondrial membranes is required to maintain mitochondrial function and biogenesis. In particular, the inner mitochondrial membrane is generally impermeable to proteins entering the matrix except via tightly regulated protein import mechanisms. Recently, cell penetrant peptides have been shown to move across the inner mitochondrial membrane in a manner suggesting an independent mechanism. HIV-1 transactivator of transcription (TAT) is an arginine-rich cell penetrant peptide, 47YGRKKRRQRRR57, which can transduce full-length proteins not only across the cell membrane but also into intracellular organelles. In this study, we investigated the ability of a TAT-containing protein to move into the mitochondrial matrix. Using a novel FACS assay for isolated, purified mitochondria, we show that TAT can deliver a modified fluorescent protein, mMDH-GFP, to the matrix of mitochondria and it is subsequently processed by the matrix peptidases. In addition, transduction of TAT-mMDH-GFP into mitochondria is independent of canonical protein import pathways as well as mitochondrial membrane potential. In direct contrast to published reports regarding the cell membrane where the sodium channel inhibitor, amiloride, blocks endocytosis and inhibits TAT transduction, TAT transduction into mitochondria is markedly increased by this same sodium channel inhibitor. These results confirm that the cell penetrant peptide, TAT, can readily transduce a protein cargo into the mitochondrial matrix. These results also demonstrate a novel role for mitochondrial sodium channels in mediating TAT transduction into mitochondria that is independent of endocytotic mechanisms. The mechanism of TAT transduction into mitochondria therefore is distinctly different from transduction across the cell membrane.
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Gordon JW, Rungi AA, Inagaki H, Hood DA. Effects of contractile activity on mitochondrial transcription factor A expression in skeletal muscle. J Appl Physiol (1985) 2001; 90:389-96. [PMID: 11133932 DOI: 10.1152/jappl.2001.90.1.389] [Citation(s) in RCA: 123] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Mitochondrial transcription factor A (Tfam) is a nuclear-encoded gene product that is imported into mitochondria and is required for the transcription of mitochondrial DNA (mtDNA). We hypothesized that conditions known to produce mitochondrial biogenesis in skeletal muscle would be preceded by an increase in Tfam expression. Therefore, rat muscle was stimulated (10 Hz, 3 h/day). Tfam mRNA levels were significantly elevated (by 55%) at 4 days and returned to control levels at 14 days. Tfam import into intermyofibrillar (IMF) mitochondria was increased by 52 and 61% (P < 0.05) at 5 and 7 days, respectively. This corresponded to an increase in the level of import machinery components. Immunoblotting data indicated that IMF Tfam protein content was increased by 63% (P < 0.05) at 7 days of stimulation. This was associated with a 49% (P < 0.05) increase in complex formation at the mtDNA promoter and a 65% (P < 0.05) increase in the levels of a mitochondrial transcript, cytochrome-c oxidase (COX) subunit III. Similarly, COX enzyme activity was elevated by 71% (P < 0.05) after 7 days of contractile activity. These results indicate that early events in mitochondrial biogenesis include increases in Tfam mRNA, followed by accelerations in mitochondrial import and increased Tfam content, which correspond with increased binding to the mtDNA promoter region. This was accompanied by increased mitochondrial transcript levels and elevated COX activity. These data support the role of Tfam as a regulatory protein involved in contractile activity-induced mitochondrial biogenesis.
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Affiliation(s)
- J W Gordon
- Kinesiology and Health Science, Faculty of Pure and Applied Science, York University, Toronto, Ontario, Canada
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Sjöling S, Waltner M, Kalousek F, Glaser E, Weiner H. Studies on protein processing for membrane-bound spinach leaf mitochondrial processing peptidase integrated into the cytochrome bc1 complex and the soluble rat liver matrix mitochondrial processing peptidase. EUROPEAN JOURNAL OF BIOCHEMISTRY 1996; 242:114-21. [PMID: 8954161 DOI: 10.1111/j.1432-1033.1996.0114r.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The plant mitochondrial processing peptidase (MPP) that catalyses the cleavage of the presequences from precursor proteins during or after protein import is a membrane-bound enzyme that constitutes an integral part of the bc1 complex of the respiratory chain. In contrast, MPP from mammals is soluble in the matrix space and does not form part of the respiratory chain. In the present study, we have compared the substrate specificity of the isolated spinach leaf bc1/MPP with rat liver MPP using synthetic signal peptides and different mitochondrial precursor proteins. Inhibition studies of processing with synthetic peptides showed a similar inhibition pattern for plant and rat MPP activity. A peptide derived from the presequence of rat liver mitochondrial aldehyde dehydrogenase (ALDH) was a potent inhibitor of the spinach and rat MPP. Two nonprocessed signal peptides, rhodanese and linker-deleted ALDH (a form of ALDH that lacks the RGP linker connecting two helices in the presequence) had lower inhibitory effects towards each protease. The signal peptide from thiolase, another nonprocessed protein, had little inhibitory effect on MPP. Peptides derived from presequence of the plant Nicotiana plumbaginifolia F1 beta also showed a similar inhibitory pattern with rat MPP as with spinach MPP processing. In-vitro synthesised precursors of plant N. plumbaginifolia F1 beta and rat liver ALDH were cleaved to mature form by both spinach and rat MPP. However, the efficiency of processing was higher with the homologous precursor. Linker-deleted ALDH, rhodanese, and thiolase were not processed by the mammalian or plant MPP. However, both forms of MPP cleaved a mutated form of rhodanese that possesses a typical MPP cleavage motif, RXY S. Addition of the same cleavage motif to thiolase did not result in processing by either MPP. These results show that similar higher-order structural elements upstream from the cleavage site are important for processing by both the membrane-bound plant and the soluble mammalian MPP.
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Affiliation(s)
- S Sjöling
- Department of Biochemistry, Arrhenius Laboratories for Natural Sciences, Stockholm University, Sweden
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Takahashi M, Hood DA. Protein import into subsarcolemmal and intermyofibrillar skeletal muscle mitochondria. Differential import regulation in distinct subcellular regions. J Biol Chem 1996; 271:27285-91. [PMID: 8910303 DOI: 10.1074/jbc.271.44.27285] [Citation(s) in RCA: 96] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
To date, no studies have described the import of proteins in mitochondria obtained from skeletal muscle. In this tissue, mitochondria consist of the functionally and biochemically distinct intermyofibrillar (IMF) and subsarcolemmal (SS) subfractions, which are localized in specialized cellular compartments. This mitochondrial heterogeneity in muscle could be due, in part, to differential rates of protein import. To evaluate this possibility, the import of precursor malate dehydrogenase and ornithine carbamyltransferase proteins was investigated in isolated IMF and SS mitochondria in vitro. Import of these was 3-4-fold greater in IMF compared with SS mitochondria as a function of time. This could account for the higher malate dehydrogenase enzyme activity in IMF mitochondria. Divergent import rates in IMF and SS mitochondria likely result from a differential reliance on various components of the import pathway. SS mitochondria possess a greater content of the molecular chaperones hsp60 and Grp75, yet import is lower than in IMF mitochondria. On the other hand, adriamycin inhibition studies illustrated a greater reliance on acidic phospholipids (i.e. cardiolipin) for the import process in SS mitochondria. Matrix ATP levels were 3-fold higher in IMF mitochondria, but experiments in which ATP depletion was performed with atractyloside and oligomycin illustrated a dissociation between import rates and levels of ATP. In contrast, a close relationship was found between the rate of ATP production (i.e. mitochondrial respiration) and protein import. When respiratory rates in IMF and SS mitochondria were equalized, import rates in both subfractions were similar. These data indicate that 1) import rates are more closely related to the rate of ATP production than the steady state ATP level, 2) import into IMF and SS mitochondrial subfractions is regulated differently, and 3) mitochondrial heterogeneity within a cell type can be due to differences in the rates of protein import, suggesting that this step is a potentially regulatable event in determining the final mitochondrial phenotype.
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Affiliation(s)
- M Takahashi
- Departments of Biology and Kinesiology, York University, North York, Ontario M3J 1P3, Canada.
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Proteolytic Processing of Mitochondrial Precursor Proteins. ACTA ACUST UNITED AC 1996. [DOI: 10.1016/s1569-2558(09)60014-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Sjöling S, Eriksson AC, Glaser E. A helical element in the C-terminal domain of the N. plumbaginifolia F1 beta presequence is important for recognition by the mitochondrial processing peptidase. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(18)31600-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Translocation of Proteins Across Chloroplast Membranes. ACTA ACUST UNITED AC 1994. [DOI: 10.1016/s1569-2558(08)60403-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
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9
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Carboxyl-terminal consensus Ser-Lys-Leu-related tripeptide of peroxisomal proteins functions in vitro as a minimal peroxisome-targeting signal. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(19)49726-3] [Citation(s) in RCA: 86] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Gietl C. Malate dehydrogenase isoenzymes: cellular locations and role in the flow of metabolites between the cytoplasm and cell organelles. BIOCHIMICA ET BIOPHYSICA ACTA 1992; 1100:217-34. [PMID: 1610875 DOI: 10.1016/0167-4838(92)90476-t] [Citation(s) in RCA: 113] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Malate dehydrogenases belong to the most active enzymes in glyoxysomes, mitochondria, peroxisomes, chloroplasts and the cytosol. In this review, the properties and the role of the isoenzymes in different compartments of the cell are compared, with emphasis on molecular biological aspects. Structure and function of malate dehydrogenase isoenzymes from plants, mammalian cells and ascomycetes (yeast, Neurospora) are considered. Significant information on evolutionary aspects and characterisation of functional domains of the enzymes emanates from bacterial malate and lactate dehydrogenases modified by protein engineering. The review endeavours to give up-to-date information on the biogenesis and intracellular targeting of malate dehydrogenase isoenzymes as well as enzymes cooperating with them in the flow of metabolites of a given pathway and organelle.
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Affiliation(s)
- C Gietl
- Institute of Botany, Technical University of Munich, München, Germany
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Douwe de Boer A, Weisbeek PJ. Chloroplast protein topogenesis: import, sorting and assembly. BIOCHIMICA ET BIOPHYSICA ACTA 1991; 1071:221-53. [PMID: 1958688 DOI: 10.1016/0304-4157(91)90015-o] [Citation(s) in RCA: 172] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- A Douwe de Boer
- Department of Molecular Cell Biology, University of Utrecht, The Netherlands
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Perry S, Buvinger W, Bennett J, Keegstra K. Synthetic analogues of a transit peptide inhibit binding or translocation of chloroplastic precursor proteins. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)99040-x] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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14
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Reversion of the Maple Syrup Urine Disease Phenotype of Impaired Branched Chain α-Ketoacid Dehydrogenase Complex Activity in Fibroblasts from an Affected Child. J Biol Chem 1989. [DOI: 10.1016/s0021-9258(18)63735-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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