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Giangregorio N, Tonazzi A, Console L, Scalise M, Indiveri C. Inhibition of the Mitochondrial Carnitine/Acylcarnitine Carrier by Itaconate through Irreversible Binding to Cysteine 136: Possible Pathophysiological Implications. Biomolecules 2023; 13:993. [PMID: 37371573 DOI: 10.3390/biom13060993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2023] [Revised: 06/11/2023] [Accepted: 06/12/2023] [Indexed: 06/29/2023] Open
Abstract
BACKGROUND The carnitine/acylcarnitine carrier (CAC) represents the route of delivering acyl moieties to the mitochondrial matrix for accomplishing the fatty acid β-oxidation. The CAC has a couple of Cys residues (C136 and C155) most reactive toward ROS and redox signaling compounds such as GSH, NO, and H2S. Among physiological compounds reacting with Cys, itaconate is produced during inflammation and represents the connection between oxidative metabolism and immune responses. The possible interaction between the CAC and itaconate has been investigated. METHODS the modulatory effects of itaconate on the transport activity of the native and recombinant CAC were tested using the proteoliposome experimental model together with site-directed mutagenesis and computational analysis. RESULTS Itaconate reacts with the CAC causing irreversible inhibition. Dose-response experiment performed with the native and recombinant protein showed IC50 for itaconate of 11 ± 4.6 mM and 8.4 ± 2.9 mM, respectively. The IC50 decreased to 3.8 ± 1.0 mM by lowering the pH from pH 7.0 to pH 6.5. Inhibition kinetics revealed a non-competitive type of inhibition. C136 is the main target of itaconate, as demonstrated by the increased IC50 of mutants in which this Cys was substituted by Val. The central role of C136 was confirmed by covalent docking. Administration of dimethyl itaconate to HeLa cells inhibited the CAC transport activity, suggesting that itaconate could react with the CAC also in intact cells.
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Affiliation(s)
- Nicola Giangregorio
- National Research Council (CNR), Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), Via Amendola 122/O, 70126 Bari, Italy
| | - Annamaria Tonazzi
- National Research Council (CNR), Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), Via Amendola 122/O, 70126 Bari, Italy
| | - Lara Console
- Unit of Biochemistry and Molecular Biotechnology, Department DiBEST (Biologia, Ecologia, Scienze della Terra), University of Calabria, Via Bucci 4C, 87036 Arcavacata di Rende, Italy
| | - Mariafrancesca Scalise
- Unit of Biochemistry and Molecular Biotechnology, Department DiBEST (Biologia, Ecologia, Scienze della Terra), University of Calabria, Via Bucci 4C, 87036 Arcavacata di Rende, Italy
| | - Cesare Indiveri
- National Research Council (CNR), Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), Via Amendola 122/O, 70126 Bari, Italy
- Unit of Biochemistry and Molecular Biotechnology, Department DiBEST (Biologia, Ecologia, Scienze della Terra), University of Calabria, Via Bucci 4C, 87036 Arcavacata di Rende, Italy
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2
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Pasquadibisceglie A, Quadrotta V, Polticelli F. In Silico Analysis of the Structural Dynamics and Substrate Recognition Determinants of the Human Mitochondrial Carnitine/Acylcarnitine SLC25A20 Transporter. Int J Mol Sci 2023; 24:ijms24043946. [PMID: 36835358 PMCID: PMC9961348 DOI: 10.3390/ijms24043946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 02/02/2023] [Accepted: 02/09/2023] [Indexed: 02/18/2023] Open
Abstract
The Carnitine-Acylcarnitine Carrier is a member of the mitochondrial Solute Carrier Family 25 (SLC25), known as SLC25A20, involved in the electroneutral exchange of acylcarnitine and carnitine across the inner mitochondrial membrane. It acts as a master regulator of fatty acids β-oxidation and is known to be involved in neonatal pathologies and cancer. The transport mechanism, also known as "alternating access", involves a conformational transition in which the binding site is accessible from one side of the membrane or the other. In this study, through a combination of state-of-the-art modelling techniques, molecular dynamics, and molecular docking, the structural dynamics of SLC25A20 and the early substrates recognition step have been analyzed. The results obtained demonstrated a significant asymmetry in the conformational changes leading to the transition from the c- to the m-state, confirming previous observations on other homologous transporters. Moreover, analysis of the MD simulations' trajectories of the apo-protein in the two conformational states allowed for a better understanding of the role of SLC25A20 Asp231His and Ala281Val pathogenic mutations, which are at the basis of Carnitine-Acylcarnitine Translocase Deficiency. Finally, molecular docking coupled to molecular dynamics simulations lend support to the multi-step substrates recognition and translocation mechanism already hypothesized for the ADP/ATP carrier.
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Affiliation(s)
| | | | - Fabio Polticelli
- Department of Sciences, University of Roma Tre, 00146 Rome, Italy
- National Institute of Nuclear Physics, Roma Tre Section, 00146 Rome, Italy
- Correspondence:
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3
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Giangregorio N, Tonazzi A, Calvano CD, Pierri CL, Incampo G, Cataldi TRI, Indiveri C. The Mycotoxin Patulin Inhibits the Mitochondrial Carnitine/Acylcarnitine Carrier (SLC25A20) by Interaction with Cys136 Implications for Human Health. Int J Mol Sci 2023; 24:ijms24032228. [PMID: 36768549 PMCID: PMC9917099 DOI: 10.3390/ijms24032228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 01/12/2023] [Accepted: 01/18/2023] [Indexed: 01/26/2023] Open
Abstract
The effect of mycotoxin patulin (4-hydroxy-4H-furo [3,2c] pyran-2 [6H] -one) on the mitochondrial carnitine/acylcarnitine carrier (CAC, SLC25A20) was investigated. Transport function was measured as [3H]-carnitineex/carnitinein antiport in proteoliposomes reconstituted with the native protein extracted from rat liver mitochondria or with the recombinant CAC over-expressed in E. coli. Patulin (PAT) inhibited both the mitochondrial native and recombinant transporters. The inhibition was not reversed by physiological and sulfhydryl-reducing reagents, such as glutathione (GSH) or dithioerythritol (DTE). The IC50 derived from the dose-response analysis indicated that PAT inhibition was in the range of 50 µM both on the native and on rat and human recombinant protein. The kinetics process revealed a competitive type of inhibition. A substrate protection experiment confirmed that the interaction of PAT with the protein occurred within a protein region, including the substrate-binding area. The mechanism of inhibition was identified using the site-directed mutagenesis of CAC. No inhibition was observed on Cys mutants in which only the C136 residue was mutated. Mass spectrometry studies and in silico molecular modeling analysis corroborated the outcomes derived from the biochemical assays.
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Affiliation(s)
- Nicola Giangregorio
- CNR Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), Via Amendola 122/O, 70126 Bari, Italy
- Correspondence:
| | - Annamaria Tonazzi
- CNR Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), Via Amendola 122/O, 70126 Bari, Italy
| | | | - Ciro Leonardo Pierri
- Department of Pharmacy-Pharmaceutical Sciences, University of Bari Aldo Moro, Via Orabona 4, 70126 Bari, Italy
| | - Giovanna Incampo
- Department of Bioscience, Biotechnology and Environment, University of Bari, 70126 Bari, Italy
| | - Tommaso R. I. Cataldi
- Department of Chemistry, University of Bari Aldo Moro, Via Orabona 4, 70126 Bari, Italy
| | - Cesare Indiveri
- CNR Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), Via Amendola 122/O, 70126 Bari, Italy
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Via Bucci 4C, Arcavacata di Rende, 87036 Cosenza, Italy
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4
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Giangregorio N, Pierri CL, Tonazzi A, Incampo G, Tragni V, De Grassi A, Indiveri C. Proline/Glycine residues of the PG-levels guide conformational changes along the transport cycle in the mitochondrial carnitine/acylcarnitine carrier (SLC25A20). Int J Biol Macromol 2022; 221:1453-1465. [PMID: 36122779 DOI: 10.1016/j.ijbiomac.2022.09.135] [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: 07/19/2022] [Revised: 09/05/2022] [Accepted: 09/15/2022] [Indexed: 11/19/2022]
Abstract
Mitochondrial carnitine/acylcarnitine carrier (CAC) is a member of the mitochondrial carrier (MC) family and imports acylcarnitine into the mitochondrial matrix in exchange for carnitine, playing a pivotal role in carnitine shuttle, crucial for fatty acid oxidation. The crystallized structure of CAC has not been solved yet, however, the availability of several in vitro/in silico studies, also based on the crystallized structures of the ADP/ATP carrier in the cytosolic-conformation and in the matrix-conformation, has made possible to confirm the hypothesis of the single-binding centered-gated pore mechanism for all the members of the MC family. In addition, our recent bioinformatics analyses allowed quantifying in silico the importance of protein residues of MC substrate binding region, of those involved in the formation of the matrix and cytosolic gates, and of those belonging to the Pro/Gly (PG) levels, proposed to be crucial for the tilting/kinking/bending of the six MC transmembrane helices, funneling the substrate translocation pathway. Here we present a combined in silico/in vitro analysis employed for investigating the role played by a group of 6 proline residues and 6 glycine residues, highly conserved in CAC, belonging to MC PG-levels. Residues of the PG-levels surround the similarly located MC common substrate binding region, and were proposed to lead conformational changes and substrate translocation, following substrate binding. For our analysis, we employed 3D molecular modeling approaches, alanine scanning site-directed mutagenesis and in vitro transport assays. Our analysis reveals that P130 (H3), G268 (H6) and G220 (H5), mutated in alanine, affect severely CAC transport activity (mutant catalytic efficiency lower than 5 % compared to the wild type CAC), most likely due to their major role in triggering CAC conformational changes, following carnitine binding. Notably, P30A (H1) and G121A (H3) CAC mutants, increase the carnitine uptake up to 217 % and 112 %, respectively, compared to the wild type CAC.
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Affiliation(s)
- Nicola Giangregorio
- CNR Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), Via Amendola 122/O, 70126 Bari, Italy.
| | - Ciro Leonardo Pierri
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Italy, Via E. Orabona, 4, 70126 Bari, Italy.
| | - Annamaria Tonazzi
- CNR Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), Via Amendola 122/O, 70126 Bari, Italy
| | - Giovanna Incampo
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Italy, Via E. Orabona, 4, 70126 Bari, Italy
| | - Vincenzo Tragni
- CNR Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), Via Amendola 122/O, 70126 Bari, Italy; Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Italy, Via E. Orabona, 4, 70126 Bari, Italy
| | - Anna De Grassi
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Italy, Via E. Orabona, 4, 70126 Bari, Italy
| | - Cesare Indiveri
- CNR Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), Via Amendola 122/O, 70126 Bari, Italy; Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Via Bucci 4C, 87036 Arcavacata di Rende, Italy
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Tonazzi A, Giangregorio N, Console L, Calvano CD, Prejanò M, Scalise M, Incampo G, Marino T, Russo N, Cataldi TRI, Indiveri C. Inhibition of the carnitine acylcarnitine carrier by carbon monoxide reveals a novel mechanism of action with non-metal-containing proteins. Free Radic Biol Med 2022; 188:395-403. [PMID: 35792242 DOI: 10.1016/j.freeradbiomed.2022.06.244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 06/02/2022] [Accepted: 06/29/2022] [Indexed: 11/19/2022]
Abstract
Both toxic and physiological effects of CO are mostly caused by well described interactions with heme-groups of proteins. Interactions of CO with non-heme proteins have also been unveiled. Besides interaction of CO with mitochondrial heme containing respiratory complexes, a BK channel and the phosphate carrier which do not contain metal cofactors, have been identified as CO targets. However, the molecular mechanisms of interaction with non-metal-containing proteins are not understood. We show in this work the effect of CO on the mitochondrial carnitine carrier (SLC25A20) using CORM-3, a widely recognized CO releasing compound. CO exerts an inhibitory effect at the micromolar concentration on the transport function of the transporter extracted from treated mitochondria. The effect is due to a single Cys residue, C136 as revealed by mass spectrometry analysis. A computational approach predicted the need for vicinal Asp and Lys residues for the C136 carbonylation to occur. These data demonstrate a novel mechanism of interaction of CO with a protein not containing metal atoms and will enable the prediction of CO targets.
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Affiliation(s)
- Annamaria Tonazzi
- CNR Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), via Amendola 122/O, 70126, Bari, Italy
| | - Nicola Giangregorio
- CNR Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), via Amendola 122/O, 70126, Bari, Italy
| | - Lara Console
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Via Bucci 4C, 87036, Arcavacata di Rende, Italy
| | - Cosima Damiana Calvano
- Department of Chemistry, University of Bari Aldo Moro, via Orabona 4, 70126, Bari, Italy
| | - Mario Prejanò
- Department CTC (Chemistry and Chemical Technology) University of Calabria, Via Bucci 14C, 87036, Arcavacata di Rende, Italy
| | - Mariafrancesca Scalise
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Via Bucci 4C, 87036, Arcavacata di Rende, Italy
| | - Giovanna Incampo
- Department of Biosciences, Biotechnology, and Biopharmaceutics, University of Bari, via Orabona 4, 70126, Bari, Italy
| | - Tiziana Marino
- Department CTC (Chemistry and Chemical Technology) University of Calabria, Via Bucci 14C, 87036, Arcavacata di Rende, Italy
| | - Nino Russo
- Department CTC (Chemistry and Chemical Technology) University of Calabria, Via Bucci 14C, 87036, Arcavacata di Rende, Italy
| | - Tommaso R I Cataldi
- Department of Chemistry, University of Bari Aldo Moro, via Orabona 4, 70126, Bari, Italy
| | - Cesare Indiveri
- CNR Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), via Amendola 122/O, 70126, Bari, Italy; Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Via Bucci 4C, 87036, Arcavacata di Rende, Italy.
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6
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Incampo G, Giangregorio N, Gambacorta N, Nicolotti O, Pacifico C, Palmieri L, Tonazzi A. Praseodymium trivalent ion is an effective inhibitor of mitochondrial basic amino acids and carnitine/acylcarnitine carriers. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2022; 1863:148557. [PMID: 35367451 DOI: 10.1016/j.bbabio.2022.148557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 03/18/2022] [Accepted: 03/25/2022] [Indexed: 06/14/2023]
Abstract
We herein report the identification of the lantanide praseodymium trivalent ion Pr3+ as inhibitor of mitochondrial transporters for basic amino acids and phylogenetically related carriers belonging to the Slc25 family. The inhibitory effect of Pr3+ has been tested using mitochondrial transporters reconstituted into liposomes being effective in the micromolar range, acting as a competitive inhibitor of the human basic amino acids carrier (BAC, Slc25A29), the human carnitine/acylcarnitine carrier (CAC, Slc25A20). Furthermore, we provide computational evidence that the complete inhibition of the transport activity of the recombinant proteins is due to the Pr3+ coordination to key acidic residues of the matrix salt bridge network. Besides being used as a first choice stop inhibitor for functional studies in vitro of mitochondrial carriers reconstituted in proteoliposomes, Pr3+ might also represent a useful tool for structural studies of the mitochondrial carrier family.
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Affiliation(s)
- Giovanna Incampo
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Via Orabona 4, 70125 Bari, Italy
| | - Nicola Giangregorio
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Via Orabona 4, 70125 Bari, Italy; CNR Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), Via Amendola 122/O, 70126 Bari, Italy
| | - Nicola Gambacorta
- Department of Pharmacy-Pharmaceutical Sciences, University of Bari, Via Orabona 4, 70125 Bari, Italy
| | - Orazio Nicolotti
- Department of Pharmacy-Pharmaceutical Sciences, University of Bari, Via Orabona 4, 70125 Bari, Italy
| | - Concetta Pacifico
- Department of Chemistry, University of Bari, Via Orabona 4, 70125 Bari, Italy
| | - Luigi Palmieri
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Via Orabona 4, 70125 Bari, Italy; CNR Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), Via Amendola 122/O, 70126 Bari, Italy
| | - Annamaria Tonazzi
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Via Orabona 4, 70125 Bari, Italy; CNR Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), Via Amendola 122/O, 70126 Bari, Italy.
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7
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Miniero DV, Monné M, Di Noia MA, Palmieri L, Palmieri F. Evidence for Non-Essential Salt Bridges in the M-Gates of Mitochondrial Carrier Proteins. Int J Mol Sci 2022; 23:ijms23095060. [PMID: 35563451 PMCID: PMC9104175 DOI: 10.3390/ijms23095060] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 04/28/2022] [Accepted: 04/29/2022] [Indexed: 01/05/2023] Open
Abstract
Mitochondrial carriers, which transport metabolites, nucleotides, and cofactors across the mitochondrial inner membrane, have six transmembrane α-helices enclosing a translocation pore with a central substrate binding site whose access is controlled by a cytoplasmic and a matrix gate (M-gate). The salt bridges formed by the three PX[DE]XX[RK] motifs located on the odd-numbered transmembrane α-helices greatly contribute to closing the M-gate. We have measured the transport rates of cysteine mutants of the charged residue positions in the PX[DE]XX[RK] motifs of the bovine oxoglutarate carrier, the yeast GTP/GDP carrier, and the yeast NAD+ transporter, which all lack one of these charged residues. Most single substitutions, including those of the non-charged and unpaired charged residues, completely inactivated transport. Double mutations of charged pairs showed that all three carriers contain salt bridges non-essential for activity. Two double substitutions of these non-essential charge pairs exhibited higher transport rates than their corresponding single mutants, whereas swapping the charged residues in these positions did not increase activity. The results demonstrate that some of the residues in the charged residue positions of the PX[DE]XX[KR] motifs are important for reasons other than forming salt bridges, probably for playing specific roles related to the substrate interaction-mediated conformational changes leading to the M-gate opening/closing.
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Affiliation(s)
- Daniela Valeria Miniero
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Via E. Orabona 4, 70125 Bari, Italy; (D.V.M.); (M.M.); (M.A.D.N.)
| | - Magnus Monné
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Via E. Orabona 4, 70125 Bari, Italy; (D.V.M.); (M.M.); (M.A.D.N.)
- Department of Sciences, University of Basilicata, Via Ateneo Lucano 10, 85100 Potenza, Italy
| | - Maria Antonietta Di Noia
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Via E. Orabona 4, 70125 Bari, Italy; (D.V.M.); (M.M.); (M.A.D.N.)
| | - Luigi Palmieri
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Via E. Orabona 4, 70125 Bari, Italy; (D.V.M.); (M.M.); (M.A.D.N.)
- CNR Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), 70126 Bari, Italy
- Correspondence: (L.P.); (F.P.)
| | - Ferdinando Palmieri
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Via E. Orabona 4, 70125 Bari, Italy; (D.V.M.); (M.M.); (M.A.D.N.)
- CNR Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), 70126 Bari, Italy
- Correspondence: (L.P.); (F.P.)
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8
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Zhang N, Jia X, Fan S, Wu B, Wang S, OuYang B. NMR Characterization of Long-Chain Fatty Acylcarnitine Binding to the Mitochondrial Carnitine/Acylcarnitine Carrier. Int J Mol Sci 2022; 23:ijms23094608. [PMID: 35563000 PMCID: PMC9103206 DOI: 10.3390/ijms23094608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 04/10/2022] [Accepted: 04/14/2022] [Indexed: 02/01/2023] Open
Abstract
The mitochondrial carnitine/acylcarnitine carrier (CAC) transports short-, medium- and long-carbon chain acylcarnitines across the mitochondrial inner membrane in exchange for carnitine. How CAC recognizes the substrates with various fatty acyl groups, especially long-chain fatty acyl groups, remains unclear. Here, using nuclear magnetic resonance (NMR) technology, we have shown that the CAC protein reconstituted into a micelle system exhibits a typical six transmembrane structure of the mitochondrial carrier family. The chemical shift perturbation patterns of different fatty acylcarnitines suggested that the segment A76–G81 in CAC specifically responds to the long-chain fatty acylcarnitine. Molecular dynamics (MD) simulations of palmitoyl-L-carnitine inside the CAC channel showed the respective interaction and motion of the long-chain acylcarnitine in CAC at the cytosol-open state and matrix-open state. Our data provided a molecular-based understanding of CAC structure and transport mechanism.
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Affiliation(s)
- Ningning Zhang
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China;
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaopu Jia
- School of Pharmacy, Tianjin Medical University, Tianjin 300070, China; (X.J.); (S.F.)
| | - Shuai Fan
- School of Pharmacy, Tianjin Medical University, Tianjin 300070, China; (X.J.); (S.F.)
| | - Bin Wu
- National Facility for Protein Science in Shanghai, ZhangJiang Laboratory, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201203, China;
| | - Shuqing Wang
- School of Pharmacy, Tianjin Medical University, Tianjin 300070, China; (X.J.); (S.F.)
- Correspondence: (S.W.); (B.O.); Tel.: +86-021-54920143 (B.O.)
| | - Bo OuYang
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China;
- University of Chinese Academy of Sciences, Beijing 100049, China
- Correspondence: (S.W.); (B.O.); Tel.: +86-021-54920143 (B.O.)
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9
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Pasquadibisceglie A, Polticelli F. Structural determinants of ligands recognition by the human mitochondrial basic amino acids transporter SLC25A29. Insights from molecular dynamics simulations of the c-state. Comput Struct Biotechnol J 2021; 19:5600-5612. [PMID: 34849194 PMCID: PMC8598871 DOI: 10.1016/j.csbj.2021.10.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 09/16/2021] [Accepted: 10/04/2021] [Indexed: 11/26/2022] Open
Abstract
In mitochondria, metabolic processes require the trafficking of solutes and organic molecules, such as amino acids. This task is accomplished by the Mitochondrial Carrier Family members (also known as SLC25), among which the SLC25A29 is responsible for the translocation of basic amino acids. In this regard, nitric oxide levels originated by the arginine mitochondrial catabolism have been shown to strongly affect cancer cells' metabolic status. Furthermore, the metabolic disease saccharopinuria has been linked to a mitochondrial dysregulation caused by a toxic intermediate of the lysine catabolism. In both cases, a reduction of the activity of SLC25A29 has been shown to ameliorate these pathological conditions. However, no detailed structural data are available on SLC25A29. In the present work, molecular modelling, docking and dynamics simulations have been employed to analyse the structural determinants of ligands recognition by SLC25A29 in the c-state. Results confirm and reinforce earlier predictions that Asn73, Arg160 and Glu161, and Arg257 represent the ligand contact points I, II, and III, respectively, and that Arg160, Trp204 and Arg257 form a stable interaction, likely critical for ligand binding and translocation. These results are discussed in view of the experimental data available for SLC25A29 and other homologous carriers of the same family.
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Affiliation(s)
| | - Fabio Polticelli
- Department of Sciences, Roma Tre University, 00146 Rome, Italy.,National Institute of Nuclear Physics, Roma Tre Section, 00146 Rome, Italy
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10
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Tonazzi A, Giangregorio N, Console L, Palmieri F, Indiveri C. The Mitochondrial Carnitine Acyl-carnitine Carrier (SLC25A20): Molecular Mechanisms of Transport, Role in Redox Sensing and Interaction with Drugs. Biomolecules 2021; 11:biom11040521. [PMID: 33807231 PMCID: PMC8066319 DOI: 10.3390/biom11040521] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 03/23/2021] [Accepted: 03/26/2021] [Indexed: 12/22/2022] Open
Abstract
The SLC25A20 transporter, also known as carnitine acyl-carnitine carrier (CAC), catalyzes the transport of short, medium and long carbon chain acyl-carnitines across the mitochondrial inner membrane in exchange for carnitine. The 30-year story of the protein responsible for this function started with its purification from rat liver mitochondria. Even though its 3D structure is not yet available, CAC is one of the most deeply characterized transport proteins of the inner mitochondrial membrane. Other than functional, kinetic and mechanistic data, post-translational modifications regulating the transport activity of CAC have been revealed. CAC interactions with drugs or xenobiotics relevant to human health and toxicology and the response of the carrier function to dietary compounds have been discovered. Exploiting combined approaches of site-directed mutagenesis with chemical targeting and bioinformatics, a large set of data on structure/function relationships have been obtained, giving novel information on the molecular mechanism of the transport catalyzed by this protein.
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Affiliation(s)
- Annamaria Tonazzi
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), National Research Council, Via Orabona 4, 70126 Bari, Italy; (A.T.); (N.G.)
| | - Nicola Giangregorio
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), National Research Council, Via Orabona 4, 70126 Bari, Italy; (A.T.); (N.G.)
| | - Lara Console
- Unit of Biochemistry and Molecular Biotechnology, Department DiBEST (Biologia, Ecologia, Scienze della Terra), University of Calabria, Via P. Bucci 4C, 87036 Arcavacata di Rende, Italy;
| | - Ferdinando Palmieri
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), National Research Council, Via Orabona 4, 70126 Bari, Italy; (A.T.); (N.G.)
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, 70125 Bari, Italy
- Correspondence: (F.P.); (C.I.); Tel.: +39-080-544-3323 (F.P.); Tel.: +39-0984-492939 (C.I.)
| | - Cesare Indiveri
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), National Research Council, Via Orabona 4, 70126 Bari, Italy; (A.T.); (N.G.)
- Unit of Biochemistry and Molecular Biotechnology, Department DiBEST (Biologia, Ecologia, Scienze della Terra), University of Calabria, Via P. Bucci 4C, 87036 Arcavacata di Rende, Italy;
- Correspondence: (F.P.); (C.I.); Tel.: +39-080-544-3323 (F.P.); Tel.: +39-0984-492939 (C.I.)
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11
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Effect of Copper on the Mitochondrial Carnitine/Acylcarnitine Carrier Via Interaction with Cys136 and Cys155. Possible Implications in Pathophysiology. Molecules 2020; 25:molecules25040820. [PMID: 32070004 PMCID: PMC7070283 DOI: 10.3390/molecules25040820] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 02/10/2020] [Accepted: 02/11/2020] [Indexed: 12/14/2022] Open
Abstract
The effect of copper on the mitochondrial carnitine/acylcarnitine carrier (CAC) was studied. Transport function was assayed as [3H]carnitine/carnitine antiport in proteoliposomes reconstituted with the native protein extracted from rat liver mitochondria or with the recombinant CAC over-expressed in E. coli. Cu2+ (as well as Cu+) strongly inhibited the native transporter. The inhibition was reversed by GSH (reduced glutathione) or by DTE (dithioerythritol). Dose-response analysis of the inhibition of the native protein was performed from which an IC50 of 1.6 µM for Cu2+ was derived. The mechanism of inhibition was studied by using the recombinant WT or Cys site-directed mutants of CAC. From the dose-response curve of the effect of Cu2+ on the recombinant protein, an IC50 of 0.28 µM was derived. Inhibition kinetics revealed a non-competitive type of inhibition by Cu2+. However, a substrate protection experiment indicated that the interaction of Cu2+ with the protein occurred in the vicinity of the substrate-binding site. Dose-response analysis on Cys mutants led to much higher IC50 values for the mutants C136S or C155S. The highest value was obtained for the C136/155S double mutant, indicating the involvement of both Cys residues in the interaction with Cu2+. Computational analysis performed on the WT CAC and on Cys mutants showed a pattern of the binding energy mostly overlapping the binding affinity derived from the dose-response analysis. All the data concur with bridging of Cu2+ with the two Cys residues, which blocks the conformational changes required for transport cycle.
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12
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Liu Q, Yin A, Wen S, Shi X, Fang L, Rao T, Liang J, Wu J. Analysis of amino acids and acylcarnitines profiles in small, appropriate, and large for gestational age neonates. J Matern Fetal Neonatal Med 2020; 35:439-446. [PMID: 32037923 DOI: 10.1080/14767058.2020.1720640] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Objective: To identify the amino acid (AA) and acylcarnitines (ACs) profiles in dry blood spot (DBS) of small, appropriate and large for gestational age neonates, and to investigate the difference AA and AC profiles in groups.Methods: Eight thousand nine hundred and fourteen healthy singleton newborns were divided into three groups: small for gestational age (SGA) (n = 713), appropriate for gestational age (AGA) (n = 7866), and LGA (n = 335). Electrospray ionization tandem mass spectrometry was taken to evaluate the concentrations of 11 AAs and 31 ACs in DBS specimens obtained from all enrolled neonates.Results: Compared with the AGA neonates, except propionylcarnitine, the concentrations of SGA neonatal most AAs and AC in the newborn were higher, while those of the newborns in the LGA group were lower.Conclusion: Different concentrations of AAs and ACs in the three groups suggest that SGA may be associated with under anabolic metabolism, while LGA may be associated with over anabolic metabolism.
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Affiliation(s)
- Qian Liu
- Department of Medical Genetics Center, Guangdong Women and Children Hospital, Guangzhou, China
| | - Aihua Yin
- Department of Medical Genetics Center, Guangdong Women and Children Hospital, Guangzhou, China
| | - Shen Wen
- Department of Reproductive Medicine, Guangdong Women and Children Hospital, Guangzhou, China
| | - Xiaomei Shi
- Department of Medical Genetics Center, Guangdong Women and Children Hospital, Guangzhou, China
| | - Liyuan Fang
- Department of Medical Genetics Center, Guangdong Women and Children Hospital, Guangzhou, China
| | - Tengzi Rao
- Department of Medical Genetics Center, Guangdong Women and Children Hospital, Guangzhou, China
| | - Jinqun Liang
- Department of Children Inherited Metabolism and Endocrine, Guangdong Women and Children Hospital, Guangzhou, China
| | - Jing Wu
- Department of Medical Genetics Center, Guangdong Women and Children Hospital, Guangzhou, China
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13
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Giangregorio N, Tonazzi A, Console L, Pistillo M, Scalera V, Indiveri C. Tryptophan 224 of the rat mitochondrial carnitine/acylcarnitine carrier is crucial for the antiport mechanism. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1860:708-716. [PMID: 31340138 DOI: 10.1016/j.bbabio.2019.07.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 07/06/2019] [Accepted: 07/18/2019] [Indexed: 01/14/2023]
Abstract
The mitochondrial carnitine/acylcarnitine carrier (CACT) catalyzes an antiport of carnitine and acylcarnitines and also a uniport reaction with a rate of about one tenth with respect to the antiport rate. The antiport process results from the coupling of the two uniport reactions in opposite directions. In this mechanism, the transition of the carrier from the outward open conformation to the inward open one (or vice versa) is much faster for the carrier-substrate complex than for the unbound carrier. To investigate the molecular determinants that couple the binding of the substrate with the conformational transitions, site directed mutagenesis has been employed. The antiport or the uniport reaction was followed as [3H]carnitine uptake in or efflux from proteoliposomes reconstituted with the WT or Trp mutants of the rat CACT. Substitution of each the three Trp residues led to different results. Nearly no variations were observed upon substitution of W192 and/or W296 with Ala. While, substantial alteration of the transport function was observed in the mutants W224A, W224Y and W224F. Mutation of W224 led to the loss of the antiport function while the uniport function was unaltered. In these mutants impairment of the substrate affinity on the external side was also observed. The data highlights that W224 is involved in the coupling of the substrate binding with the matrix gate opening. The experimental data are in line with predictions by homology modeling of the CACT in its cytosolic (c-state) or matrix (m-state) opened conformations.
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Affiliation(s)
- Nicola Giangregorio
- CNR Institute of Biomembranes, Bioenergetics and Molecular Biotechnology, via Amendola 165/A, 70126 Bari, Italy
| | - Annamaria Tonazzi
- CNR Institute of Biomembranes, Bioenergetics and Molecular Biotechnology, via Amendola 165/A, 70126 Bari, Italy
| | - Lara Console
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Via P. Bucci 4C, 87036 Arcavacata di Rende, Italy
| | - Mariella Pistillo
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, via Orabona 4, 70126 Bari, Italy
| | - Vito Scalera
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, via Orabona 4, 70126 Bari, Italy
| | - Cesare Indiveri
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Via P. Bucci 4C, 87036 Arcavacata di Rende, Italy.
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14
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Console L, Giangregorio N, Cellamare S, Bolognino I, Palasciano M, Indiveri C, Incampo G, Campana S, Tonazzi A. Human mitochondrial carnitine acylcarnitine carrier: Molecular target of dietary bioactive polyphenols from sweet cherry (Prunus avium L.). Chem Biol Interact 2019; 307:179-185. [PMID: 31063765 DOI: 10.1016/j.cbi.2019.05.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 05/03/2019] [Accepted: 05/03/2019] [Indexed: 12/11/2022]
Abstract
The effect of polyphenols, recognized as the principal antioxidant and beneficial molecules introduced with the diet, extracted from sweet cherry (Prunus avium L.) on the recombinant human mitochondrial carnitine/acylcarnitine transporter (CACT) has been studied in proteoliposomes. CACT transport activity, which was strongly impaired after oxidation by atmospheric O2 or H2O2, due to the formation of a disulfide bridge between cysteines 136 and 155, was restored by externally added polyphenols. CACT reduction by polyphenols was time dependent. Spectroscopic analysis of polyphenolic extracts revealed eight most represented compounds in four cultivars. Molecular docking of CACT structural omology model with the most either abundant and arguably bio-available phenolic compound (trans 3-O-feruloyl-quinic acid) of the mix, is in agreement with the experimental data since it results located in the active site close to cysteine 136 at the bottom of the translocation aqueous cavity.
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Affiliation(s)
- Lara Console
- Department DiBEST (Biologia, Ecologia, Scienze della Terra), Unit of Biochemistry and Molecular Biotechnology, Via Bucci 4C, University of Calabria, 87036, Arcavacata di Rende, Italy
| | - Nicola Giangregorio
- CNR-IBIOM (Institute of Biomembranes, Bioenergetics and Molecular Biotechnology), via Amendola 165/A, 70126, Bari, Italy; Department of Bioscience, Biotechnology and Biopharmaceutics, Via Orabona 4, 70125, University of Bari, Italy
| | - Saverio Cellamare
- Dipartimento di Farmacia-Scienze del Farmaco, Via Orabona 4, 70125, University of Bari, Italy
| | - Isabella Bolognino
- Dipartimento di Farmacia-Scienze del Farmaco, Via Orabona 4, 70125, University of Bari, Italy
| | - Marino Palasciano
- DiSSPA (Department of Soil, Plant and Food Science), University of Bari, via Amendola 165/A, 70126, Bari, Italy
| | - Cesare Indiveri
- Department DiBEST (Biologia, Ecologia, Scienze della Terra), Unit of Biochemistry and Molecular Biotechnology, Via Bucci 4C, University of Calabria, 87036, Arcavacata di Rende, Italy; CNR-IBIOM (Institute of Biomembranes, Bioenergetics and Molecular Biotechnology), via Amendola 165/A, 70126, Bari, Italy
| | - Giovanna Incampo
- CNR-IBIOM (Institute of Biomembranes, Bioenergetics and Molecular Biotechnology), via Amendola 165/A, 70126, Bari, Italy; Department of Bioscience, Biotechnology and Biopharmaceutics, Via Orabona 4, 70125, University of Bari, Italy
| | - Sabrina Campana
- Department of Bioscience, Biotechnology and Biopharmaceutics, Via Orabona 4, 70125, University of Bari, Italy
| | - Annamaria Tonazzi
- CNR-IBIOM (Institute of Biomembranes, Bioenergetics and Molecular Biotechnology), via Amendola 165/A, 70126, Bari, Italy; Department of Bioscience, Biotechnology and Biopharmaceutics, Via Orabona 4, 70125, University of Bari, Italy.
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15
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Giangregorio N, Tonazzi A, Console L, Galluccio M, Porcelli V, Indiveri C. Structure/function relationships of the human mitochondrial ornithine/citrulline carrier by Cys site-directed mutagenesis. Relevance to mercury toxicity. Int J Biol Macromol 2018; 120:93-99. [DOI: 10.1016/j.ijbiomac.2018.08.069] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 08/12/2018] [Accepted: 08/14/2018] [Indexed: 12/19/2022]
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16
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Post-translational modification by acetylation regulates the mitochondrial carnitine/acylcarnitine transport protein. Mol Cell Biochem 2016; 426:65-73. [PMID: 27864727 DOI: 10.1007/s11010-016-2881-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 11/08/2016] [Indexed: 12/17/2022]
Abstract
The carnitine/acylcarnitine transporter (CACT; SLC25A20) mediates an antiport reaction allowing entry of acyl moieties in the form of acylcarnitines into the mitochondrial matrix and exit of free carnitine. The transport function of CACT is crucial for the β-oxidation pathway. In this work, it has been found that CACT is partially acetylated in rat liver mitochondria as demonstrated by anti-acetyl-lys antibody immunostaining. Acetylation was reversed by the deacetylase Sirtuin 3 in the presence of NAD+. After treatment of the mitochondrial extract with the deacetylase, the CACT activity, assayed in proteoliposomes, increased. The half-saturation constant of the CACT was not influenced, while the V max was increased by deacetylation. Sirtuin 3 was not able to deacetylate the CACT when incubation was performed in intact mitoplasts, indicating that the acetylation sites are located in the mitochondrial matrix. Prediction on the localization of acetylated residues by bioinformatics correlates well with the experimental data. Recombinant CACT treated with acetyl-CoA was partially acetylated by non-enzymatic mechanism with a corresponding decrease of transport activity. The experimental data indicate that acetylation of CACT inhibits its transport activity, and thus may contribute to the regulation of the mitochondrial β-oxidation pathway.
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17
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The mitochondrial carnitine/acylcarnitine carrier is regulated by hydrogen sulfide via interaction with C136 and C155. Biochim Biophys Acta Gen Subj 2015; 1860:20-7. [PMID: 26459002 DOI: 10.1016/j.bbagen.2015.10.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Revised: 09/24/2015] [Accepted: 10/08/2015] [Indexed: 11/20/2022]
Abstract
BACKGROUND The carnitine/acylcarnitine carrier (CAC or CACT) mediates transport of acylcarnitines into mitochondria for the β-oxidation. CAC possesses Cys residues which respond to redox changes undergoing to SH/disulfide interconversion. METHODS The effect of H2S has been investigated on the [(3)H]carnitine/carnitine antiport catalyzed by recombinant or native CAC reconstituted in proteoliposomes. Site-directed mutagenesis was employed for identifying Cys reacting with H2S. RESULTS H2S led to transport inhibition, which was dependent on concentration, pH and time of incubation. Best inhibition with IC50 of 0.70 μM was observed at physiological pH after 30-60 min incubation. At longer times of incubation, inhibition was reversed. After oxidation of the carrier by O2, transport activity was rescued by H2S indicating that the inhibition/activation depends on the initial redox state of the protein. The observed effects were more efficient on the native rat liver transporter than on the recombinant protein. Only the protein containing both C136 and C155 responded to the reagent as the WT. While reduced responses were observed in the mutants containing C136 or C155. Multi-alignment of known mitochondrial carriers, highlighted that only the CAC possesses both Cys residues. This correlates well with the absence of effects of H2S on carriers which does not contain the Cys couple. CONCLUSIONS Altogether, these data demonstrate that H2S regulates the CAC by inhibiting or activating transport on the basis of the redox state of the protein. GENERAL SIGNIFICANCE CAC represents a specific target of H2S among mitochondrial carriers in agreement with the presence of a reactive Cys couple.
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18
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Monné M, Palmieri F. Antiporters of the mitochondrial carrier family. CURRENT TOPICS IN MEMBRANES 2014; 73:289-320. [PMID: 24745987 DOI: 10.1016/b978-0-12-800223-0.00008-6] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The eukaryotic transport protein family SLC25 consists of mitochondrial carriers (MCs) that are recognized on the sequence level by a threefold repeated and conserved signature motif. The majority of MCs characterized so far catalyzes strict exchanges of substrates across the mitochondrial inner membrane. The substrates are nucleotides, metabolic intermediates, and cofactors that are required in cytoplasmic and matrix metabolism. This review summarizes and discusses the current knowledge of the antiport mechanism(s) of MCs that has been deduced from determining transport characteristics and by analyzing structural, sequence, and mutagenesis data. The mode of transport varies among different MCs with respect to how the substrate translocation depends on the electrical and pH gradients across the mitochondrial inner membrane, for example, the ADP/ATP carrier is electrogenic (electrophoretic), the GTP/GDP carrier is dependent on the pH gradient, the aspartate/glutamate carrier is dependent on both, and the oxoglutarate/malate carrier is independent of them. The structure of the bovine ADP/ATP carrier consists of a six-transmembrane α-helix bundle with a pseudo-threefold symmetry and a closed matrix gate. By using this structure as a template in homology modeling, residues engaged in substrate binding and the formation of a cytoplasmic gate in MCs have been proposed. The functional importance of the residues of the binding site, the matrix, and the cytoplasmic gates is supported by transport activities of different MCs with single point mutations. Cumulative evidence has been used to postulate a general transport mechanism for MCs.
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Affiliation(s)
- Magnus Monné
- Department of Biosciences, Biotechnology and Biopharmaceutics, Laboratory of Biochemistry and Molecular Biology, University of Bari, Bari, Italy; Department of Sciences, University of Basilicata, Potenza, Italy
| | - Ferdinando Palmieri
- Department of Biosciences, Biotechnology and Biopharmaceutics, Laboratory of Biochemistry and Molecular Biology, University of Bari, Bari, Italy.
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19
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Giangregorio N, Console L, Tonazzi A, Palmieri F, Indiveri C. Identification of amino acid residues underlying the antiport mechanism of the mitochondrial carnitine/acylcarnitine carrier by site-directed mutagenesis and chemical labeling. Biochemistry 2014; 53:6924-33. [PMID: 25325845 DOI: 10.1021/bi5009112] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The mitochondrial carnitine/acylcarnitine carrier catalyzes the transport of carnitine and acylcarnitines by antiport as well as by uniport with a rate slower than the rate of antiport. The mechanism of antiport resulting from coupling of two opposed uniport reactions was investigated by site-directed mutagenesis. The transport reaction was followed as [(3)H]carnitine uptake in or efflux from proteoliposomes reconstituted with the wild type or mutants, in the presence or absence of a countersubstrate. The ratio between the antiport and uniport rates for the wild type was 3.0 or 2.5, using the uptake or efflux procedure, respectively. This ratio did not vary substantially in mutants H29A, K35R, G121A, E132A, K135A, R178A, D179E, E191A, K194A, K234A, and E288A. A ratio of 1.0 was measured for mutant K35A, indicating a loss of antiport function by this mutant. Ratios of >1.0 but significantly lower than that of the wild type were measured for mutants D32A, K97A, and D231A, indicating the involvement of these residues in the antiport mechanism. To investigate the role of the countersubstrate in the conformational changes underlying the transport reaction, the m-state of the transporter (opened toward the matrix side) was specifically labeled with N-ethylmaleimide while the c-state of the carrier (opened toward the cytosolic side) was labeled with fluorescein maleimide. The labeling results indicated that the addition of an external substrate, on one hand, reduced the amount of protein in the m-state and, on the other, increased the protein fraction in the c-state. This substrate-induced conformational change was abolished in the protein lacking K35, pointing to the role of this residue as a sensor in the mechanism of the antiport reaction.
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Affiliation(s)
- Nicola Giangregorio
- CNR Institute of Biomembranes and Bioenergetics , via Amendola 165/A, 70126 Bari, Italy
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20
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Console L, Giangregorio N, Indiveri C, Tonazzi A. Carnitine/acylcarnitine translocase and carnitine palmitoyltransferase 2 form a complex in the inner mitochondrial membrane. Mol Cell Biochem 2014; 394:307-14. [DOI: 10.1007/s11010-014-2098-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Accepted: 05/15/2014] [Indexed: 12/19/2022]
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21
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Porcelli V, Fiermonte G, Longo A, Palmieri F. The human gene SLC25A29, of solute carrier family 25, encodes a mitochondrial transporter of basic amino acids. J Biol Chem 2014; 289:13374-84. [PMID: 24652292 DOI: 10.1074/jbc.m114.547448] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The human genome encodes 53 members of the solute carrier family 25 (SLC25), also called the mitochondrial carrier family, many of which have been shown to transport carboxylates, amino acids, nucleotides, and cofactors across the inner mitochondrial membrane, thereby connecting cytosolic and matrix functions. In this work, a member of this family, SLC25A29, previously reported to be a mitochondrial carnitine/acylcarnitine- or ornithine-like carrier, has been thoroughly characterized biochemically. The SLC25A29 gene was overexpressed in Escherichia coli, and the gene product was purified and reconstituted in phospholipid vesicles. Its transport properties and kinetic parameters demonstrate that SLC25A29 transports arginine, lysine, homoarginine, methylarginine and, to a much lesser extent, ornithine and histidine. Carnitine and acylcarnitines were not transported by SLC25A29. This carrier catalyzed substantial uniport besides a counter-exchange transport, exhibited a high transport affinity for arginine and lysine, and was saturable and inhibited by mercurial compounds and other inhibitors of mitochondrial carriers to various degrees. The main physiological role of SLC25A29 is to import basic amino acids into mitochondria for mitochondrial protein synthesis and amino acid degradation.
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Affiliation(s)
- Vito Porcelli
- From the Department of Biosciences, Biotechnologies and Biopharmaceutics, Laboratory of Biochemistry and Molecular Biology and
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22
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Pierri CL, Palmieri F, De Grassi A. Single-nucleotide evolution quantifies the importance of each site along the structure of mitochondrial carriers. Cell Mol Life Sci 2014; 71:349-64. [PMID: 23800987 PMCID: PMC11113836 DOI: 10.1007/s00018-013-1389-y] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Revised: 05/10/2013] [Accepted: 05/27/2013] [Indexed: 11/28/2022]
Abstract
Mitochondrial carriers are membrane-embedded proteins consisting of a tripartite structure, a three-fold pseudo-symmetry, related sequences, and similar folding whose main function is to catalyze the transport of various metabolites, nucleotides, and coenzymes across the inner mitochondrial membrane. In this study, the evolutionary rate in vertebrates was screened at each of the approximately 50,000 nucleotides corresponding to the amino acids of the 53 human mitochondrial carriers. Using this information as a starting point, a scoring system was developed to quantify the evolutionary pressure acting on each site of the common mitochondrial carrier structure and estimate its functional or structural relevance. The degree of evolutionary selection varied greatly among all sites, but it was highly similar among the three symmetric positions in the tripartite structure, known as symmetry-related sites or triplets, suggesting that each triplet constitutes an evolutionary unit. Based on evolutionary selection, 111 structural sites (37 triplets) were found to be important. These sites play a key role in structure/function of mitochondrial carriers and are involved in either conformational changes (sites of the gates, proline-glycine levels, and aromatic belts) or in binding and specificity of the transported substrates (sites of the substrate-binding area in between the two gates). Furthermore, the evolutionary pressure analysis revealed that the matrix short helix sites underwent different degrees of selection with high inter-paralog variability. Evidence is presented that these sites form a new sequence motif in a subset of mitochondrial carriers, including the ADP/ATP translocator, and play a regulatory function by interacting with ligands and/or proteins of the mitochondrial matrix.
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Affiliation(s)
- Ciro Leonardo Pierri
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Via Orabona 4, 70125 Bari, Italy
| | - Ferdinando Palmieri
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Via Orabona 4, 70125 Bari, Italy
- Center of Excellence in Comparative Genomics, University of Bari, Bari, Italy
| | - Anna De Grassi
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Via Orabona 4, 70125 Bari, Italy
- Département Systématique et Evolution, Ecole Pratique des Hautes Etudes, Muséum National d’Histoire Naturelle, Paris, France
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Tonazzi A, Eberini I, Indiveri C. Molecular mechanism of inhibition of the mitochondrial carnitine/acylcarnitine transporter by omeprazole revealed by proteoliposome assay, mutagenesis and bioinformatics. PLoS One 2013; 8:e82286. [PMID: 24349247 PMCID: PMC3857281 DOI: 10.1371/journal.pone.0082286] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 10/30/2013] [Indexed: 11/20/2022] Open
Abstract
The effect of omeprazole on the mitochondrial carnitine/acylcarnitine transporter has been studied in proteoliposomes. Externally added omeprazole inhibited the carnitine/carnitine antiport catalysed by the transporter. The inhibition was partially reversed by DTE indicating that it was caused by the covalent reaction of omeprazole with Cys residue(s). Inhibition of the C-less mutant transporter indicated also the occurrence of an alternative non-covalent mechanism. The IC50 of the inhibition of the WT and the C-less CACT by omeprazole were 5.4 µM and 29 µM, respectively. Inhibition kinetics showed non competitive inhibition of the WT and competitive inhibition of the C-less. The presence of carnitine or acylcarnitines during the incubation of the proteoliposomes with omeprazole increased the inhibition. Using site-directed Cys mutants it was demonstrated that C283 and C136 were essential for covalent inhibition. Molecular docking of omeprazole with CACT indicated the formation of both covalent interactions with C136 and C283 and non-covalent interactions in agreement with the experimental data.
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Affiliation(s)
| | - Ivano Eberini
- Laboratorio di Biochimica e Biofisica Computazionale, Dipartimento di Scienze Farmacologiche e Biomolecolari, Sezione di Biochimica, Biofisica, Fisiologia ed Immunopatologia, Università degli Studi di Milano, Milano, Italy
| | - Cesare Indiveri
- CNR Institute of Biomembranes and Bioenergetics, Bari, Italy
- Department BEST (Biologia, Ecologia, Scienze della Terra), Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Arcavacata di Rende, Italy
- * E-mail:
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Glutathione controls the redox state of the mitochondrial carnitine/acylcarnitine carrier Cys residues by glutathionylation. Biochim Biophys Acta Gen Subj 2013; 1830:5299-304. [PMID: 23948593 DOI: 10.1016/j.bbagen.2013.08.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Revised: 07/26/2013] [Accepted: 08/05/2013] [Indexed: 01/13/2023]
Abstract
BACKGROUND The mitochondrial carnitine/acylcarnitine carrier (CAC) is essential for cell metabolism since it catalyzes the transport of acylcarnitines into mitochondria allowing the β-oxidation of fatty acids. CAC functional and structural properties have been characterized. Cys residues which could form disulfides suggest the involvement of CAC in redox switches. METHODS The effect of GSH and GSSG on the [(3)H]-carnitine/carnitine antiport catalyzed by the CAC in proteoliposomes has been studied. The Cys residues involved in the redox switch have been identified by site-directed mutagenesis. Glutathionylated CAC has been assessed by glutathionyl-protein specific antibody. RESULTS GSH led to increase of transport activity of the CAC extracted from liver mitochondria. A similar effect was observed on the recombinant CAC. The presence of glutaredoxin-1 (Grx1) accelerated the GSH activation of the recombinant CAC. The effect was more evident at 37°C. GSSG led to transport inhibition which was reversed by dithioerythritol (DTE). The effects of GSH and GSSG were studied on CAC Cys-mutants. CAC lacking C136 and C155 was insensitive to both reagents. Mutants containing these two Cys responded as the wild-type. Anti-glutathionyl antibody revealed the formation of glutathionylated CAC. CONCLUSIONS CAC is redox-sensitive and it is regulated by the GSH/GSSG couple. C136 and C155 are responsible for the regulation which occurs through glutathionylation. GENERAL SIGNIFICANCE CAC is sensitive to the redox state of the cell switching between oxidized and reduced forms in response to variation of GSSG and GSH concentrations.
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Monné M, Miniero DV, Iacobazzi V, Bisaccia F, Fiermonte G. The mitochondrial oxoglutarate carrier: from identification to mechanism. J Bioenerg Biomembr 2013; 45:1-13. [PMID: 23054077 DOI: 10.1007/s10863-012-9475-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The 2-oxoglutarate carrier (OGC) belongs to the mitochondrial carrier protein family whose members are responsible for the exchange of metabolites, cofactors and nucleotides between the cytoplasm and mitochondrial matrix. Initially, OGC was characterized by determining substrate specificity, kinetic parameters of transport, inhibitors and molecular probes that form covalent bonds with specific residues. It was shown that OGC specifically transports oxoglutarate and certain carboxylic acids. The substrate specificity combination of OGC is unique, although many of its substrates are also transported by other mitochondrial carriers. The abundant recombinant expression of bovine OGC in Escherichia coli and its ability to functionally reconstitute into proteoliposomes made it possible to deduce the individual contribution of each and every residue of OGC to the transport activity by a complete set of cys-scanning mutants. These studies give experimental support for a substrate binding site constituted by three major contact points on the even-numbered α-helices and identifies other residues as important for transport function through their crucial positions in the structure for conserved interactions and the conformational changes of the carrier during the transport cycle. The results of these investigations have led to utilize OGC as a model protein for understanding the transport mechanism of mitochondrial carriers.
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Affiliation(s)
- Magnus Monné
- Department of Biosciences, Biotechnology and Pharmacological Sciences, Laboratory of Biochemistry and Molecular Biology, University of Bari, Via E. Orabona 4, 70125 Bari, Italy.
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Tonazzi A, Console L, Indiveri C. Inhibition of mitochondrial carnitine/acylcarnitine transporter by H2O2: Molecular mechanism and possible implication in pathophysiology. Chem Biol Interact 2013; 203:423-9. [DOI: 10.1016/j.cbi.2013.01.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2012] [Revised: 01/14/2013] [Accepted: 01/31/2013] [Indexed: 12/29/2022]
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Transcriptional Regulation of the Mitochondrial Citrate and Carnitine/Acylcarnitine Transporters: Two Genes Involved in Fatty Acid Biosynthesis and β-oxidation. BIOLOGY 2013; 2:284-303. [PMID: 24832661 PMCID: PMC4009865 DOI: 10.3390/biology2010284] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Revised: 01/18/2013] [Accepted: 01/23/2013] [Indexed: 12/17/2022]
Abstract
Transcriptional regulation of genes involved in fatty acid metabolism is considered the major long-term regulatory mechanism controlling lipid homeostasis. By means of this mechanism, transcription factors, nutrients, hormones and epigenetics control not only fatty acid metabolism, but also many metabolic pathways and cellular functions at the molecular level. The regulation of the expression of many genes at the level of their transcription has already been analyzed. This review focuses on the transcriptional control of two genes involved in fatty acid biosynthesis and oxidation: the citrate carrier (CIC) and the carnitine/ acylcarnitine/carrier (CAC), which are members of the mitochondrial carrier gene family, SLC25. The contribution of tissue-specific and less tissue-specific transcription factors in activating or repressing CIC and CAC gene expression is discussed. The interaction with drugs of some transcription factors, such as PPAR and FOXA1, and how this interaction can be an attractive therapeutic approach, has also been evaluated. Moreover, the mechanism by which the expression of the CIC and CAC genes is modulated by coordinated responses to hormonal and nutritional changes and to epigenetics is highlighted.
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Monné M, Palmieri F, Kunji ERS. The substrate specificity of mitochondrial carriers: mutagenesis revisited. Mol Membr Biol 2012; 30:149-59. [PMID: 23121155 DOI: 10.3109/09687688.2012.737936] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Mitochondrial carriers transport inorganic ions, nucleotides, amino acids, keto acids and cofactors across the mitochondrial inner membrane. Structurally they consist of three domains, each containing two transmembrane α-helices linked by a short α-helix and loop. The substrate binds to three major contact points in the central cavity. The class of substrate (e.g., adenine nucleotides) is determined by contact point II on transmembrane α-helix H4 and the type of substrate within the class (e.g., ADP, coenzyme A) by contact point I in H2, whereas contact point III on H6 is most usually a positively charged residue, irrespective of the type or class. Two salt bridge networks, consisting of conserved and symmetric residues, are located on the matrix and cytoplasmic side of the cavity. These residues are part of the gates that are involved in opening and closing of the carrier during the transport cycle, exposing the central substrate binding site to either side of the membrane in an alternating way. Here we revisit the plethora of mutagenesis data that have been collected over the last two decades to see if the residues in the proposed binding site and salt bridge networks are indeed important for function. The analysis shows that the major contact points of the substrate binding site are indeed crucial for function and in defining the specificity. The matrix salt bridge network is more critical for function than the cytoplasmic salt bridge network in agreement with its central position, but neither is likely to be involved in substrate recognition directly.
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Affiliation(s)
- Magnus Monné
- Department of Biosciences, Biotechnology and Pharmacological Sciences, Laboratory of Biochemistry and Molecular Biology, University of Bari, Bari, Italy
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Agrimi G, Russo A, Pierri CL, Palmieri F. The peroxisomal NAD+ carrier of Arabidopsis thaliana transports coenzyme A and its derivatives. J Bioenerg Biomembr 2012; 44:333-40. [PMID: 22555559 DOI: 10.1007/s10863-012-9445-0] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Accepted: 04/19/2012] [Indexed: 12/31/2022]
Abstract
The peroxisomal protein PXN encoded by the Arabidopsis gene At2g39970 has very recently been found to transport NAD+, NADH, AMP and ADP. In this work we have reinvestigated the substrate specificity and the transport properties of PXN by using a wide range of potential substrates. Heterologous expression in bacteria followed by purification, reconstitution in liposomes, and uptake and efflux experiments revealed that PNX transports coenzyme A (CoA), dephospho-CoA, acetyl-CoA and adenosine 3', 5'-phosphate (PAP), besides NAD+, NADH, AMP and ADP. PXN catalyzed fast counter-exchange of substrates and much slower uniport and was strongly inhibited by pyridoxal 5'-phosphate, bathophenanthroline and tannic acid. Transport was saturable with a submillimolar affinity for NAD+, CoA and other substrates. The physiological role of PXN is probably to provide the peroxisomes with the essential coenzymes NAD+ and CoA.
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Affiliation(s)
- Gennaro Agrimi
- Department of Biosciences, Biotechnology and Pharmacological Sciences, University of Bari, Via Orabona 4, 70125 Bari, Italy
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Tonazzi A, Console L, Giangregorio N, Indiveri C, Palmieri F. Identification by site-directed mutagenesis of a hydrophobic binding site of the mitochondrial carnitine/acylcarnitine carrier involved in the interaction with acyl groups. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1817:697-704. [PMID: 22365929 DOI: 10.1016/j.bbabio.2012.02.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Revised: 01/30/2012] [Accepted: 02/07/2012] [Indexed: 10/28/2022]
Abstract
The role of hydrophobic residues of the mitochondrial carnitine/acylcarnitine carrier (CAC) in the inhibition by acylcarnitines has been investigated by site-directed mutagenesis. According to the homology model of CAC in cytosolic opened conformation (c-state), L14, G17, G21, V25, P78, V82, M85, C89, F93, A276, A279, C283, F287 are located in the 1st (H1), 2nd (H2) and 6th (H6) transmembrane α-helices and exposed in the central cavity, forming a hydrophobic half shell. These residues have been substituted with A (or G) and in some cases with M. Mutants have been assayed for transport activity measured as [(3)H]carnitine/carnitine antiport in proteoliposomes. With the exception of G17A and G21M, mutants exhibited activity from 20% to 100% of WT. Among the active mutants only G21A, V25M, P78A and P78M showed Vmax lower than half and/or Km more than two fold respect to WT. Acylcarnitines competitively inhibited carnitine antiport. The extent of inhibition of the mutants by acylcarnitines with acyl chain length of 2, 4, 8, 12, 14 and 16 has been compared with the WT. V25A, P78A, P78M and A279G showed reduced extent of inhibition by all the acylcarnitines; V25M showed reduced inhibition by shorter acylcarnitines; V82A, V82M, M85A, C89A and A276G showed reduced inhibition by longer acylcarnitines, respect to WT. C283A showed increased extent of inhibition by acylcarnitines. Variations of Ki of mutants for acylcarnitines reflected variations of the inhibition profiles. The data demonstrated that V25, P78, V82, M85 and C89 are involved in the acyl chain binding to the CAC in c-state.
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Affiliation(s)
- Annamaria Tonazzi
- Department of Biosciences, Biotechnology and Pharmacological Sciences, Laboratory of Biochemistry and Molecular Biology, University of Bari, 70125 Bari, Italy
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Monné M, Miniero DV, Daddabbo L, Robinson AJ, Kunji ERS, Palmieri F. Substrate specificity of the two mitochondrial ornithine carriers can be swapped by single mutation in substrate binding site. J Biol Chem 2012; 287:7925-34. [PMID: 22262851 DOI: 10.1074/jbc.m111.324855] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mitochondrial carriers are a large family of proteins that transport specific metabolites across the inner mitochondrial membrane. Sequence and structure analysis has indicated that these transporters have substrate binding sites in a similar location of the central cavity consisting of three major contact points. Here we have characterized mutations of the proposed substrate binding site in the human ornithine carriers ORC1 and ORC2 by carrying out transport assays with a set of different substrates. The different substrate specificities of the two isoforms, which share 87% identical amino acids, were essentially swapped by exchanging a single residue located at position 179 that is arginine in ORC1 and glutamine in ORC2. Altogether the substrate specificity changes demonstrate that Arg-179 and Glu-180 of contact point II bind the C(α) carboxylate and amino group of the substrates, respectively. Residue Glu-77 of contact point I most likely interacts with the terminal amino group of the substrate side chain. Furthermore, it is likely that all three contact points are involved in the substrate-induced conformational changes required for substrate translocation because Arg-179 is probably connected with Arg-275 of contact point III through Trp-224 by cation-π interactions. Mutations at position 179 also affected the turnover number of the ornithine carrier severely, implying that substrate binding to residue 179 is a rate-limiting step of the catalytic transport cycle. Given that Arg-179 is located in the vicinity of the matrix gate, it is concluded that it is a key residue in the opening of the carrier to the matrix side.
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Affiliation(s)
- Magnus Monné
- Department of Pharmaco-Biology, Laboratory of Biochemistry and Molecular Biology, University of Bari, Via E. Orabona 4, 70125 Bari, Italy
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Indiveri C, Iacobazzi V, Tonazzi A, Giangregorio N, Infantino V, Convertini P, Console L, Palmieri F. The mitochondrial carnitine/acylcarnitine carrier: Function, structure and physiopathology. Mol Aspects Med 2011; 32:223-33. [DOI: 10.1016/j.mam.2011.10.008] [Citation(s) in RCA: 161] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Accepted: 10/11/2011] [Indexed: 01/01/2023]
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Palmieri F, Pierri CL, De Grassi A, Nunes-Nesi A, Fernie AR. Evolution, structure and function of mitochondrial carriers: a review with new insights. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2011; 66:161-81. [PMID: 21443630 DOI: 10.1111/j.1365-313x.2011.04516.x] [Citation(s) in RCA: 176] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The mitochondrial carriers (MC) constitute a large family (MCF) of inner membrane transporters displaying different substrate specificities, patterns of gene expression and even non-mitochondrial organelle localization. In Arabidopsis thaliana 58 genes encode these six trans-membrane domain proteins. The number in other sequenced plant genomes varies from 37 to 125, thus being larger than that of Saccharomyces cerevisiae and comparable with that of Homo sapiens. In addition to displaying highly similar secondary structures, the proteins of the MCF can be subdivided into subfamilies on the basis of substrate specificity and the presence of specific symmetry-related amino acid triplets. We assessed the predictive power of these triplets by comparing predictions with experimentally determined data for Arabidopsis MCs, and applied these predictions to the not yet functionally characterized mitochondrial carriers of the grass, Brachypodium distachyon, and the alga, Ostreococcus lucimarinus. We additionally studied evolutionary aspects of the plant MCF by comparing sequence data of the Arabidopsis MCF with those of Saccharomyces cerevisiae and Homo sapiens, then with those of Brachypodium distachyon and Ostreococcus lucimarinus, employing intra- and inter-genome comparisons. Finally, we discussed the importance of the approaches of global gene expression analysis and in vivo characterizations in order to address the relevance of these vital carrier proteins.
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Affiliation(s)
- Ferdinando Palmieri
- Laboratory of Biochemistry and Molecular Biology, Department of Pharmaco-Biology, University of Bari, Via Orabona 4, 70125 Bari, Italy.
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Kunji ERS, Robinson AJ. Coupling of proton and substrate translocation in the transport cycle of mitochondrial carriers. Curr Opin Struct Biol 2010; 20:440-7. [DOI: 10.1016/j.sbi.2010.06.004] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Accepted: 06/03/2010] [Indexed: 10/19/2022]
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