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Škulj S, Brkljača Z, Kreiter J, Pohl EE, Vazdar M. Molecular Dynamics Simulations of Mitochondrial Uncoupling Protein 2. Int J Mol Sci 2021; 22:ijms22031214. [PMID: 33530558 PMCID: PMC7866055 DOI: 10.3390/ijms22031214] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/19/2021] [Accepted: 01/22/2021] [Indexed: 11/16/2022] Open
Abstract
Molecular dynamics (MD) simulations of uncoupling proteins (UCP), a class of transmembrane proteins relevant for proton transport across inner mitochondrial membranes, represent a complicated task due to the lack of available structural data. In this work, we use a combination of homology modelling and subsequent microsecond molecular dynamics simulations of UCP2 in the DOPC phospholipid bilayer, starting from the structure of the mitochondrial ATP/ADP carrier (ANT) as a template. We show that this protocol leads to a structure that is impermeable to water, in contrast to MD simulations of UCP2 structures based on the experimental NMR structure. We also show that ATP binding in the UCP2 cavity is tight in the homology modelled structure of UCP2 in agreement with experimental observations. Finally, we corroborate our results with conductance measurements in model membranes, which further suggest that the UCP2 structure modeled from ANT protein possesses additional key functional elements, such as a fatty acid-binding site at the R60 region of the protein, directly related to the proton transport mechanism across inner mitochondrial membranes.
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Affiliation(s)
- Sanja Škulj
- Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia; (S.Š.); (Z.B.)
| | - Zlatko Brkljača
- Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia; (S.Š.); (Z.B.)
| | - Jürgen Kreiter
- Department of Biomedical Sciences, Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine, 1210 Vienna, Austria;
| | - Elena E. Pohl
- Department of Biomedical Sciences, Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine, 1210 Vienna, Austria;
- Correspondence: (E.E.P.); (M.V.)
| | - Mario Vazdar
- Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia; (S.Š.); (Z.B.)
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, 16610 Prague, Czech Republic
- Correspondence: (E.E.P.); (M.V.)
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Tragni V, Cotugno P, De Grassi A, Massari F, Di Ronzo F, Aresta AM, Zambonin C, Sanzani SM, Ippolito A, Pierri CL. Targeting mitochondrial metabolite transporters in Penicillium expansum for reducing patulin production. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2021; 158:158-181. [PMID: 33250320 DOI: 10.1016/j.plaphy.2020.07.027] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Revised: 06/30/2020] [Accepted: 07/13/2020] [Indexed: 06/12/2023]
Abstract
There is an increasing need of alternative treatments to control fungal infection and consequent mycotoxin accumulation in harvested fruits and vegetables. Indeed, only few biological targets of antifungal agents have been characterized and can be used for limiting fungal spread from decayed fruits/vegetables to surrounding healthy ones during storage. On this concern, a promising target of new antifungal treatments may be represented by mitochondrial proteins due to some species-specific functions played by mitochondria in fungal morphogenesis, drug resistance and virulence. One of the most studied mycotoxins is patulin produced by several species of Penicillium and Aspergillus genera. Patulin is toxic to many biological systems including bacteria, higher plants and animalia. Although precise biochemical mechanisms of patulin toxicity in humans are not completely clarified, its high presence in fresh and processed apple fruits and other apple-based products makes necessary developing a strategy for limiting its presence/accumulation. Patulin biosynthetic pathway consists of an enzymatic cascade, whose first step is represented by the synthesis of 6-methylsalicylic acid, obtained from the condensation of one acetyl-CoA molecule with three malonyl-CoA molecules. The most abundant acetyl-CoA precursor is represented by citrate produced by mitochondria. In the present investigation we report about the possibility to control patulin production through the inhibition of mitochondrial/peroxisome transporters involved in the export of acetyl-CoA precursors from mitochondria and/or peroxisomes, with specific reference to the predicted P. expansum mitochondrial Ctp1p, DTC, Sfc1p, Oac1p and peroxisomal PXN carriers.
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Affiliation(s)
- Vincenzo Tragni
- Department of Soil, Plant and Food Sciences, University of Bari Aldo Moro, Via Amendola 165/A, 70126, Bari, Italy
| | - Pietro Cotugno
- Biology Department, University of Bari Aldo Moro, Via Amendola 165/A, 70126, Bari, Italy
| | - Anna De Grassi
- Laboratory of Biochemistry, Molecular and Structural Biology, Department of Biosciences, Biotechnologies, Biopharmaceutics, University of Bari, Via E. Orabona, 4, 70125, Bari, Italy; BROWSer S.r.l. (https://browser-bioinf.com/) c/o, Department of Biosciences, Biotechnologies, Biopharmaceutics, University "Aldo Moro" of Bari, Via E. Orabona, 4, 70126, Bari, Italy
| | - Federica Massari
- Biology Department, University of Bari Aldo Moro, Via Amendola 165/A, 70126, Bari, Italy
| | - Francesco Di Ronzo
- Laboratory of Biochemistry, Molecular and Structural Biology, Department of Biosciences, Biotechnologies, Biopharmaceutics, University of Bari, Via E. Orabona, 4, 70125, Bari, Italy
| | - Antonella Maria Aresta
- Chemistry Department, University of Bari Aldo Moro, Via Amendola 165/A, 70126, Bari, Italy
| | - Carlo Zambonin
- Chemistry Department, University of Bari Aldo Moro, Via Amendola 165/A, 70126, Bari, Italy
| | | | - Antonio Ippolito
- Department of Soil, Plant and Food Sciences, University of Bari Aldo Moro, Via Amendola 165/A, 70126, Bari, Italy.
| | - Ciro Leonardo Pierri
- Laboratory of Biochemistry, Molecular and Structural Biology, Department of Biosciences, Biotechnologies, Biopharmaceutics, University of Bari, Via E. Orabona, 4, 70125, Bari, Italy; BROWSer S.r.l. (https://browser-bioinf.com/) c/o, Department of Biosciences, Biotechnologies, Biopharmaceutics, University "Aldo Moro" of Bari, Via E. Orabona, 4, 70126, Bari, Italy.
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Singha UK, Tripathi A, Smith JT, Quinones L, Saha A, Singha T, Chaudhuri M. Novel IM-associated protein Tim54 plays a role in the mitochondrial import of internal signal-containing proteins in Trypanosoma brucei. Biol Cell 2021; 113:39-57. [PMID: 33084070 PMCID: PMC8265390 DOI: 10.1111/boc.202000054] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Accepted: 08/28/2020] [Indexed: 01/16/2023]
Abstract
BACKGROUND The translocase of the mitochondrial inner membrane (TIM) imports most of the nucleus-encoded proteins that are destined for the matrix, inner membrane (IM) and the intermembrane space (IMS). Trypanosoma brucei, the infectious agent for African trypanosomiasis, possesses a unique TIM complex consisting of several novel proteins in association with a relatively conserved protein TbTim17. Tandem affinity purification of the TbTim17 protein complex revealed TbTim54 as a potential component of this complex. RESULTS TbTim54, a trypanosome-specific IMS protein, is peripherally associated with the IM and is present in a protein complex slightly larger than the TbTim17 complex. TbTim54 knockdown (KD) reduced the import of TbTim17 and compromised the integrity of the TbTim17 complex. TbTim54 KD inhibited the in vitro mitochondrial import and assembly of the internal signal-containing mitochondrial carrier proteins MCP3, MCP5 and MCP11 to a greater extent than TbTim17 KD. Furthermore, TbTim54 KD, but not TbTim17 KD, significantly hampered the mitochondrial targeting of ectopically expressed MCP3 and MCP11. These observations along with our previous finding that the mitochondrial import of N-terminal signal-containing proteins like cytochrome oxidase subunit 4 and MRP2 was affected to a greater extent by TbTim17 KD than TbTim54 KD indicating a substrate-specificity of TbTim54 for internal-signal containing mitochondrial proteins. In other organisms, small Tim chaperones in the IMS are known to participate in the translocation of MCPs. We found that TbTim54 can directly interact with at least two of the six known small TbTim proteins, TbTim11 and TbTim13, as well as with the N-terminal domain of TbTim17. CONCLUSION TbTim54 interacts with TbTim17. It also plays a crucial role in the mitochondrial import and complex assembly of internal signal-containing IM proteins in T. brucei. SIGNIFICANCE We are the first to characterise TbTim54, a novel TbTim that is involved primarily in the mitochondrial import of MCPs and TbTim17 in T. brucei.
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Mao X, Yao S, Yi Q, Xu ZM, Cang X. Function-related asymmetry of the specific cardiolipin binding sites on the mitochondrial ADP/ATP carrier. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2021; 1863:183466. [PMID: 32871114 DOI: 10.1016/j.bbamem.2020.183466] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 08/16/2020] [Accepted: 08/24/2020] [Indexed: 01/04/2023]
Abstract
The ADP/ATP carrier (AAC) transports matrix ATP and cytosolic ADP across the inner mitochondrial membrane (IMM). It is well known that cardiolipin (CL) plays an important role in regulating the function of AAC, yet the underlying mechanism still remains elusive. AAC is composed of three homologous domains, and three specific CL binding sites are located at the domain-domain interfaces near the matrix side. Here we report an in-depth investigation on the dynamic properties of the bound CL within the three specific sites through all-atom molecular dynamics simulations of up to 13 μs in total. Our results highlight the importance of the basic and polar residues in CL binding. The basic residues from the linker helix and/or the [Y/W/F][K/R]G motif enable the bound CL to form an intra-domain binding mode, and the canonical inter-domain binding mode only forms when these basic residues are occupied by an additional phospholipid. Of special significance, differences in the basic and polar residues lead to remarkable asymmetry among the three specific CL binding sites. We found that the bound CL at the interface of domains 2 and 3 predominantly adopts inter-domain binding mode, while CLs at the other two sites have much more intra-domain populations. This is consistent with the asymmetric crystal structure of the matrix state (m-state) AAC which implies an asymmetric transport mechanism. The dynamic equilibrium between the inter-domain and intra-domain binding modes observed in our simulations could be highly important for the bound CLs to adapt to the movements during state transitions.
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Affiliation(s)
- Xiaoting Mao
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310052, China; Institute of Genetics, Department of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Shihao Yao
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310052, China; Institute of Genetics, Department of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Qiuzi Yi
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310052, China; Institute of Genetics, Department of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Zhe-Ming Xu
- Department of Urology, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health and National Children's Regional Medical Center, Hangzhou, Zhejiang 310052, China
| | - Xiaohui Cang
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310052, China; Institute of Genetics, Department of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.
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Zhao L, Tang M, Bode AM, Liao W, Cao Y. ANTs and cancer: Emerging pathogenesis, mechanisms, and perspectives. Biochim Biophys Acta Rev Cancer 2020; 1875:188485. [PMID: 33309965 DOI: 10.1016/j.bbcan.2020.188485] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 11/03/2020] [Accepted: 11/21/2020] [Indexed: 12/15/2022]
Abstract
Adenine nucleotide translocases (ANTs) are a class of transporters located in the inner mitochondrial membrane that not only couple processes of cellular productivity and energy expenditure, but are also involved in the composition of the mitochondrial membrane permeability transition pore (mPTP). The function of ANTs has been found to be most closely related to their own conformational changes. Notably, as multifunctional proteins, ANTs play a key role in oncogenesis, which provides building blocks for tumor anabolism, control oxidative phosphorylation and glycolysis homeostasis, and govern cell death. Thus, ANTs constitute promising targets for the development of novel anticancer agents. Here, we review the recent findings regarding ANTs and their important mechanisms in cancer, with a focus on the therapeutic potential of targeting ANTs for cancer therapy.
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Affiliation(s)
- Lin Zhao
- Key Laboratory of Carcinogenesis and Cancer Invasion, Chinese Ministry of Education, Department of Radiology, Xiangya Hospital, Central South University, Changsha 410078, China; Cancer Research Institute and School of Basic Medical Science, Xiangya School of Medicine, Central South University, Changsha 410078, China; Key Laboratory of Carcinogenesis, Chinese Ministry of Health, Changsha 410078, China
| | - Min Tang
- Key Laboratory of Carcinogenesis and Cancer Invasion, Chinese Ministry of Education, Department of Radiology, Xiangya Hospital, Central South University, Changsha 410078, China; Cancer Research Institute and School of Basic Medical Science, Xiangya School of Medicine, Central South University, Changsha 410078, China; Key Laboratory of Carcinogenesis, Chinese Ministry of Health, Changsha 410078, China
| | - Ann M Bode
- The Hormel Institute, University of Minnesota, Austin, MN, USA
| | - Weihua Liao
- Department of Radiology, Xiangya Hospital, Central South University, Changsha 410078, China
| | - Ya Cao
- Key Laboratory of Carcinogenesis and Cancer Invasion, Chinese Ministry of Education, Department of Radiology, Xiangya Hospital, Central South University, Changsha 410078, China; Cancer Research Institute and School of Basic Medical Science, Xiangya School of Medicine, Central South University, Changsha 410078, China; Key Laboratory of Carcinogenesis, Chinese Ministry of Health, Changsha 410078, China; Molecular Imaging Research Center of Central South University, Changsha 410008, Hunan, China; Research Center for Technologies of Nucleic Acid-Based Diagnostics and Therapeutics Hunan Province, Changsha 410078, China; National Joint Engineering Research Center for Genetic Diagnostics of Infectious Diseases and Cancer, Changsha 410078, China.
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Piel MS, Masscheleyn S, Bouillaud F, Moncoq K, Miroux B. Structural models of mitochondrial uncoupling proteins obtained in DPC micelles are not functionally relevant. FEBS J 2020; 288:3024-3033. [DOI: 10.1111/febs.15629] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 10/15/2020] [Accepted: 11/13/2020] [Indexed: 11/30/2022]
Affiliation(s)
- Mathilde S. Piel
- Laboratoire de Biologie Physico‐Chimique des Protéines Membranaires, LBPC‐PM CNRS UMR7099 Université de Paris France
- Institut de Biologie Physico‐Chimique Fondation Edmond de Rothschild pour le Développement de la Recherche Scientifique Paris France
| | - Sandrine Masscheleyn
- Laboratoire de Biologie Physico‐Chimique des Protéines Membranaires, LBPC‐PM CNRS UMR7099 Université de Paris France
- Institut de Biologie Physico‐Chimique Fondation Edmond de Rothschild pour le Développement de la Recherche Scientifique Paris France
| | | | - Karine Moncoq
- Laboratoire de Biologie Physico‐Chimique des Protéines Membranaires, LBPC‐PM CNRS UMR7099 Université de Paris France
- Institut de Biologie Physico‐Chimique Fondation Edmond de Rothschild pour le Développement de la Recherche Scientifique Paris France
| | - Bruno Miroux
- Laboratoire de Biologie Physico‐Chimique des Protéines Membranaires, LBPC‐PM CNRS UMR7099 Université de Paris France
- Institut de Biologie Physico‐Chimique Fondation Edmond de Rothschild pour le Développement de la Recherche Scientifique Paris France
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Gyimesi G, Hediger MA. Sequence Features of Mitochondrial Transporter Protein Families. Biomolecules 2020; 10:E1611. [PMID: 33260588 PMCID: PMC7761412 DOI: 10.3390/biom10121611] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 11/20/2020] [Accepted: 11/22/2020] [Indexed: 02/08/2023] Open
Abstract
Mitochondrial carriers facilitate the transfer of small molecules across the inner mitochondrial membrane (IMM) to support mitochondrial function and core cellular processes. In addition to the classical SLC25 (solute carrier family 25) mitochondrial carriers, the past decade has led to the discovery of additional protein families with numerous members that exhibit IMM localization and transporter-like properties. These include mitochondrial pyruvate carriers, sideroflexins, and mitochondrial cation/H+ exchangers. These transport proteins were linked to vital physiological functions and disease. Their structures and transport mechanisms are, however, still largely unknown and understudied. Protein sequence analysis per se can often pinpoint hotspots that are of functional or structural importance. In this review, we summarize current knowledge about the sequence features of mitochondrial transporters with a special focus on the newly included SLC54, SLC55 and SLC56 families of the SLC solute carrier superfamily. Taking a step further, we combine sequence conservation analysis with transmembrane segment and secondary structure prediction methods to extract residue positions and sequence motifs that likely play a role in substrate binding, binding site gating or structural stability. We hope that our review will help guide future experimental efforts by the scientific community to unravel the transport mechanisms and structures of these novel mitochondrial carriers.
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Affiliation(s)
- Gergely Gyimesi
- Membrane Transport Discovery Lab, Department of Nephrology and Hypertension, and Department of Biomedical Research, Inselspital, University of Bern, Kinderklinik, Freiburgstrasse 15, CH-3010 Bern, Switzerland;
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58
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A Single Cysteine Residue in the Translocation Pathway of the Mitosomal ADP/ATP Carrier from Cryptosporidium parvum Confers a Broad Nucleotide Specificity. Int J Mol Sci 2020; 21:ijms21238971. [PMID: 33255957 PMCID: PMC7730227 DOI: 10.3390/ijms21238971] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 11/09/2020] [Accepted: 11/23/2020] [Indexed: 12/18/2022] Open
Abstract
Cryptosporidiumparvum is a clinically important eukaryotic parasite that causes the disease cryptosporidiosis, which manifests with gastroenteritis-like symptoms. The protist has mitosomes, which are organelles of mitochondrial origin that have only been partially characterized. The genome encodes a highly reduced set of transport proteins of the SLC25 mitochondrial carrier family of unknown function. Here, we have studied the transport properties of one member of the C. parvum carrier family, demonstrating that it resembles the mitochondrial ADP/ATP carrier of eukaryotes. However, this carrier has a broader substrate specificity for nucleotides, transporting adenosine, thymidine, and uridine di- and triphosphates in contrast to its mitochondrial orthologues, which have a strict substrate specificity for ADP and ATP. Inspection of the putative translocation pathway highlights a cysteine residue, which is a serine in mitochondrial ADP/ATP carriers. When the serine residue is replaced by cysteine or larger hydrophobic residues in the yeast mitochondrial ADP/ATP carrier, the substrate specificity becomes broad, showing that this residue is important for nucleotide base selectivity in ADP/ATP carriers.
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59
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Kory N, Uit de Bos J, van der Rijt S, Jankovic N, Güra M, Arp N, Pena IA, Prakash G, Chan SH, Kunchok T, Lewis CA, Sabatini DM. MCART1/SLC25A51 is required for mitochondrial NAD transport. SCIENCE ADVANCES 2020; 6:sciadv.abe5310. [PMID: 33087354 PMCID: PMC7577609 DOI: 10.1126/sciadv.abe5310] [Citation(s) in RCA: 87] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 09/04/2020] [Indexed: 05/19/2023]
Abstract
The nicotinamide adenine dinucleotide (NAD+/NADH) pair is a cofactor in redox reactions and is particularly critical in mitochondria as it connects substrate oxidation by the tricarboxylic acid (TCA) cycle to adenosine triphosphate generation by the electron transport chain (ETC) and oxidative phosphorylation. While a mitochondrial NAD+ transporter has been identified in yeast, how NAD enters mitochondria in metazoans is unknown. Here, we mine gene essentiality data from human cell lines to identify MCART1 (SLC25A51) as coessential with ETC components. MCART1-null cells have large decreases in TCA cycle flux, mitochondrial respiration, ETC complex I activity, and mitochondrial levels of NAD+ and NADH. Isolated mitochondria from cells lacking or overexpressing MCART1 have greatly decreased or increased NAD uptake in vitro, respectively. Moreover, MCART1 and NDT1, a yeast mitochondrial NAD+ transporter, can functionally complement for each other. Thus, we propose that MCART1 is the long sought mitochondrial transporter for NAD in human cells.
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Affiliation(s)
- Nora Kory
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA
- Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Department of Biology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
- Broad Institute of Harvard and Massachusetts Institute of Technology, 415 Main Street, Cambridge MA 02142, USA
| | - Jelmi Uit de Bos
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA
| | - Sanne van der Rijt
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA
| | - Nevena Jankovic
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA
| | - Miriam Güra
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA
| | - Nicholas Arp
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA
| | - Izabella A Pena
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA
| | - Gyan Prakash
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA
| | - Sze Ham Chan
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA
| | - Tenzin Kunchok
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA
| | - Caroline A Lewis
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA
| | - David M Sabatini
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA.
- Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Department of Biology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
- Broad Institute of Harvard and Massachusetts Institute of Technology, 415 Main Street, Cambridge MA 02142, USA
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60
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Senoo N, Kandasamy S, Ogunbona OB, Baile MG, Lu Y, Claypool SM. Cardiolipin, conformation, and respiratory complex-dependent oligomerization of the major mitochondrial ADP/ATP carrier in yeast. SCIENCE ADVANCES 2020; 6:eabb0780. [PMID: 32923632 PMCID: PMC7455186 DOI: 10.1126/sciadv.abb0780] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 07/08/2020] [Indexed: 05/30/2023]
Abstract
The phospholipid cardiolipin has pleiotropic structural and functional roles that are collectively essential for mitochondrial biology. Yet, the molecular details of how this lipid supports the structure and function of proteins and protein complexes are poorly understood. To address this property of cardiolipin, we use the mitochondrial adenosine 5'-diphosphate/adenosine 5'-triphosphate carrier (Aac) as a model. Here, we have determined that cardiolipin is critical for both the tertiary and quaternary assembly of the major yeast Aac isoform Aac2 as well as its conformation. Notably, these cardiolipin-provided structural roles are separable. In addition, we show that multiple copies of Aac2 engage in shared complexes that are largely dependent on the presence of assembled respiratory complexes III and IV or respiratory supercomplexes. Intriguingly, the assembly state of Aac2 is sensitive to its transport-related conformation. Together, these results expand our understanding of the numerous structural roles provided by cardiolipin for mitochondrial membrane proteins.
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Zhang Y, Fernie AR. On the Detection and Functional Significance of the Protein-Protein Interactions of Mitochondrial Transport Proteins. Biomolecules 2020; 10:E1107. [PMID: 32722450 PMCID: PMC7464641 DOI: 10.3390/biom10081107] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 07/21/2020] [Accepted: 07/23/2020] [Indexed: 12/23/2022] Open
Abstract
Protein-protein assemblies are highly prevalent in all living cells. Considerable evidence has recently accumulated suggesting that particularly transient association/dissociation of proteins represent an important means of regulation of metabolism. This is true not only in the cytosol and organelle matrices, but also at membrane surfaces where, for example, receptor complexes, as well as those of key metabolic pathways, are common. Transporters also frequently come up in lists of interacting proteins, for example, binding proteins that catalyze the production of their substrates or that act as relays within signal transduction cascades. In this review, we provide an update of technologies that are used in the study of such interactions with mitochondrial transport proteins, highlighting the difficulties that arise in their use for membrane proteins and discussing our current understanding of the biological function of such interactions.
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Affiliation(s)
- Youjun Zhang
- Center of Plant Systems Biology and Biotechnology, 4000 Plovdiv, Bulgaria
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Alisdair R. Fernie
- Center of Plant Systems Biology and Biotechnology, 4000 Plovdiv, Bulgaria
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
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62
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Fernie AR, Cavalcanti JHF, Nunes-Nesi A. Metabolic Roles of Plant Mitochondrial Carriers. Biomolecules 2020; 10:E1013. [PMID: 32650612 PMCID: PMC7408384 DOI: 10.3390/biom10071013] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 06/28/2020] [Accepted: 06/29/2020] [Indexed: 02/07/2023] Open
Abstract
Mitochondrial carriers (MC) are a large family (MCF) of inner membrane transporters displaying diverse, yet often redundant, substrate specificities, as well as differing spatio-temporal patterns of expression; there are even increasing examples of non-mitochondrial subcellular localization. The number of these six trans-membrane domain proteins in sequenced plant genomes ranges from 39 to 141, rendering the size of plant families larger than that found in Saccharomyces cerevisiae and comparable with Homo sapiens. Indeed, comparison of plant MCs with those from these better characterized species has been highly informative. Here, we review the most recent comprehensive studies of plant MCFs, incorporating the torrent of genomic data emanating from next-generation sequencing techniques. As such we present a more current prediction of the substrate specificities of these carriers as well as review the continuing quest to biochemically characterize this feature of the carriers. Taken together, these data provide an important resource to guide direct genetic studies aimed at addressing the relevance of these vital carrier proteins.
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Affiliation(s)
- Alisdair R. Fernie
- Max-Planck-Instiute of Molecular Plant Physiology, 14476 Postdam-Golm, Germany
| | - João Henrique F. Cavalcanti
- Instituto de Educação, Agricultura e Ambiente, Universidade Federal do Amazonas, Humaitá 69800-000, Amazonas, Brazil;
| | - Adriano Nunes-Nesi
- Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa 36570-900, Minas Gerais, Brazil
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Linden A, Deckers M, Parfentev I, Pflanz R, Homberg B, Neumann P, Ficner R, Rehling P, Urlaub H. A Cross-linking Mass Spectrometry Approach Defines Protein Interactions in Yeast Mitochondria. Mol Cell Proteomics 2020; 19:1161-1178. [PMID: 32332106 PMCID: PMC7338081 DOI: 10.1074/mcp.ra120.002028] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 04/24/2020] [Indexed: 12/13/2022] Open
Abstract
Protein cross-linking and the analysis of cross-linked peptides by mass spectrometry is currently receiving much attention. Not only is this approach applied to isolated complexes to provide information about spatial arrangements of proteins, but it is also increasingly applied to entire cells and their organelles. As in quantitative proteomics, the application of isotopic labeling further makes it possible to monitor quantitative changes in the protein-protein interactions between different states of a system. Here, we cross-linked mitochondria from Saccharomyces cerevisiae grown on either glycerol- or glucose-containing medium to monitor protein-protein interactions under non-fermentative and fermentative conditions. We investigated qualitatively the protein-protein interactions of the 400 most abundant proteins applying stringent data-filtering criteria, i.e. a minimum of two cross-linked peptide spectrum matches and a cut-off in the spectrum scoring of the used search engine. The cross-linker BS3 proved to be equally suited for connecting proteins in all compartments of mitochondria when compared with its water-insoluble but membrane-permeable derivative DSS. We also applied quantitative cross-linking to mitochondria of both the growth conditions using stable-isotope labeled BS3. Significant differences of cross-linked proteins under glycerol and glucose conditions were detected, however, mainly because of the different copy numbers of these proteins in mitochondria under both the conditions. Results obtained from the glycerol condition indicate that the internal NADH:ubiquinone oxidoreductase Ndi1 is part of an electron transport chain supercomplex. We have also detected several hitherto uncharacterized proteins and identified their interaction partners. Among those, Min8 was found to be associated with cytochrome c oxidase. BN-PAGE analyses of min8Δ mitochondria suggest that Min8 promotes the incorporation of Cox12 into cytochrome c oxidase.
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Affiliation(s)
- Andreas Linden
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany; Institute of Clinical Chemistry, University Medical Center Göttingen, Göttingen, Germany
| | - Markus Deckers
- Department of Cellular Biochemistry, University Medical Center Göttingen, Göttingen, Germany
| | - Iwan Parfentev
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Ralf Pflanz
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Bettina Homberg
- Department of Cellular Biochemistry, University Medical Center Göttingen, Göttingen, Germany
| | - Piotr Neumann
- Department of Molecular Structural Biology, Institute for Microbiology and Genetics, Göttingen Center for Molecular Biosciences, Georg-August-University Göttingen, Göttingen, Germany
| | - Ralf Ficner
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany; Department of Molecular Structural Biology, Institute for Microbiology and Genetics, Göttingen Center for Molecular Biosciences, Georg-August-University Göttingen, Göttingen, Germany
| | - Peter Rehling
- Department of Cellular Biochemistry, University Medical Center Göttingen, Göttingen, Germany; Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany; Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany; Institute of Clinical Chemistry, University Medical Center Göttingen, Göttingen, Germany.
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64
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Nozawa A, Ito D, Ibrahim M, Santos HJ, Tsuboi T, Tozawa Y. Characterization of mitochondrial carrier proteins of malaria parasite Plasmodium falciparum based on in vitro translation and reconstitution. Parasitol Int 2020; 79:102160. [PMID: 32574727 DOI: 10.1016/j.parint.2020.102160] [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] [Received: 04/22/2020] [Revised: 06/14/2020] [Accepted: 06/15/2020] [Indexed: 02/07/2023]
Abstract
Members of the mitochondrial carrier (MC) family of membrane transporters play important roles in cellular metabolism. We previously established an in vitro reconstitution system for membrane transporters based on wheat germ cell-free translation system. We have now applied this reconstitution system to the comparative analysis of MC proteins from the malaria parasite Plasmodium falciparum and Saccharomyces cerevisiae. We synthesized twelve putative P. falciparum MCs and determined the transport activities of four of these proteins including PF3D7_1037300 protein (ADP/ATP translocator), PF3D7_1004800 protein (ADP/ATP translocator), PF3D7_1202200 protein (phosphate carrier), and PF3D7_1241600 protein (S-adenosylmethionine transporter). In addition, we tested the effect of cardiolipin on the activity of MC proteins. The transport activities of the yeast MCs, ScAac2p, ScGgc1p, ScDic1p, ScPic1p, and ScSam5p, which localize to the mitochondrial inner membrane, were increased by cardiolipin supplementation, whereas that of ScAnt1p, which localizes to the peroxisome membrane, was not significantly affected. Together, this indicates that the functional properties of the reconstituted MCs reflect the lipid content of their native membranes. Except for PF3D7_1241600 protein, these P. falciparum proteins manifested cardiolipin-dependent transport activities. Immunofluorescence analysis showed that PF3D7_1241600 protein is not mainly localized to the mitochondria of P. falciparum cells. We thus revealed the functions of four MC proteins of the malaria parasite and the effects of cardiolipin on their activities.
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Affiliation(s)
- Akira Nozawa
- Proteo-Science Center, Ehime University, 3 Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan.
| | - Daisuke Ito
- Proteo-Science Center, Ehime University, 3 Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan; Division of Medical Zoology, Department of Microbiology and Immunology, Faculty of Medicine, Tottori University, 86 Nishi-cho, Yonago, Tottori 683-8503, Japan.
| | - Mohamed Ibrahim
- Faculty of Science, Ain Shams University, Cairo 11566, Egypt.
| | - Herbert J Santos
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan; Department of Parasitology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan.
| | - Takafumi Tsuboi
- Proteo-Science Center, Ehime University, 3 Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan.
| | - Yuzuru Tozawa
- Proteo-Science Center, Ehime University, 3 Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan; Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama, Saitama 338-8570, Japan.
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65
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Bround MJ, Bers DM, Molkentin JD. A 20/20 view of ANT function in mitochondrial biology and necrotic cell death. J Mol Cell Cardiol 2020; 144:A3-A13. [PMID: 32454061 DOI: 10.1016/j.yjmcc.2020.05.012] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 04/16/2020] [Accepted: 05/20/2020] [Indexed: 12/25/2022]
Abstract
The adenosine nucleotide translocase (ANT) family of proteins are inner mitochondrial membrane proteins involved in energy homeostasis and cell death. The primary function of ANT proteins is to exchange cytosolic ADP with matrix ATP, facilitating the export of newly synthesized ATP to the cell while providing new ADP substrate to the mitochondria. As such, the ANT proteins are central to maintaining energy homeostasis in all eukaryotic cells. Evidence also suggests that the ANTs constitute a pore-forming component of the mitochondrial permeability transition pore (MPTP), a structure that forms in the inner mitochondrial membrane that is thought to underlie regulated necrotic cell death. Additionally, emerging studies suggest that ANT proteins are also critical for mitochondrial uncoupling and for promoting mitophagy. Thus, the ANTs are multifunctional proteins that are poised to participate in several aspects of mitochondrial biology and the greater regulation of cell death, which will be discussed here.
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Affiliation(s)
- Michael J Bround
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, OH 45229, USA
| | - Donald M Bers
- Department of Pharmacology, University of California, Davis, Davis, CA 95616, USA
| | - Jeffery D Molkentin
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, OH 45229, USA; Howard Hughes Medical Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA.
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66
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Škulj S, Brkljača Z, Vazdar M. Molecular Dynamics Simulations of the Elusive Matrix‐Open State of Mitochondrial ADP/ATP Carrier. Isr J Chem 2020. [DOI: 10.1002/ijch.202000011] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Sanja Škulj
- Division of Organic Chemistry and BiochemistryRuđer Bošković Institute Bijenička 54 HR-10000 Zagreb Croatia
| | - Zlatko Brkljača
- Division of Organic Chemistry and BiochemistryRuđer Bošković Institute Bijenička 54 HR-10000 Zagreb Croatia
| | - Mario Vazdar
- Division of Organic Chemistry and BiochemistryRuđer Bošković Institute Bijenička 54 HR-10000 Zagreb Croatia
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67
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Bertero E, Kutschka I, Maack C, Dudek J. Cardiolipin remodeling in Barth syndrome and other hereditary cardiomyopathies. Biochim Biophys Acta Mol Basis Dis 2020; 1866:165803. [PMID: 32348916 DOI: 10.1016/j.bbadis.2020.165803] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 12/19/2019] [Accepted: 04/13/2020] [Indexed: 12/18/2022]
Abstract
Mitochondria play a prominent role in cardiac energy metabolism, and their function is critically dependent on the integrity of mitochondrial membranes. Disorders characterized by mitochondrial dysfunction are commonly associated with cardiac disease. The mitochondrial phospholipid cardiolipin directly interacts with a number of essential protein complexes in the mitochondrial membranes including the respiratory chain, mitochondrial metabolite carriers, and proteins critical for mitochondrial morphology. Barth syndrome is an X-linked disorder caused by an inherited defect in the biogenesis of the mitochondrial phospholipid cardiolipin. How cardiolipin deficiency impacts on mitochondrial function and how mitochondrial dysfunction causes cardiomyopathy has been intensively studied in cellular and animal models of Barth syndrome. These findings may also have implications for the molecular mechanisms underlying other inherited disorders associated with defects in cardiolipin, such as Sengers syndrome and dilated cardiomyopathy with ataxia (DCMA).
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Affiliation(s)
- Edoardo Bertero
- Comprehensive Heart Failure Center (CHFC), University Clinic Würzburg, 97078 Würzburg, Germany
| | - Ilona Kutschka
- Comprehensive Heart Failure Center (CHFC), University Clinic Würzburg, 97078 Würzburg, Germany
| | - Christoph Maack
- Comprehensive Heart Failure Center (CHFC), University Clinic Würzburg, 97078 Würzburg, Germany
| | - Jan Dudek
- Comprehensive Heart Failure Center (CHFC), University Clinic Würzburg, 97078 Würzburg, Germany.
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68
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Cunningham CN, Rutter J. 20,000 picometers under the OMM: diving into the vastness of mitochondrial metabolite transport. EMBO Rep 2020; 21:e50071. [PMID: 32329174 DOI: 10.15252/embr.202050071] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 02/17/2020] [Accepted: 03/27/2020] [Indexed: 12/14/2022] Open
Abstract
The metabolic compartmentalization enabled by mitochondria is key feature of many cellular processes such as energy conversion to ATP production, redox balance, and the biosynthesis of heme, urea, nucleotides, lipids, and others. For a majority of these functions, metabolites need to be transported across the impermeable inner mitochondrial membrane by dedicated carrier proteins. Here, we examine the substrates, structural features, and human health implications of four mitochondrial metabolite carrier families: the SLC25A family, the mitochondrial ABCB transporters, the mitochondrial pyruvate carrier (MPC), and the sideroflexin proteins.
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Affiliation(s)
- Corey N Cunningham
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Jared Rutter
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, USA.,Howard Hughes Medical Institute, University of Utah School of Medicine, Salt Lake City, UT, USA
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69
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Palmieri F, Scarcia P, Monné M. Diseases Caused by Mutations in Mitochondrial Carrier Genes SLC25: A Review. Biomolecules 2020; 10:biom10040655. [PMID: 32340404 PMCID: PMC7226361 DOI: 10.3390/biom10040655] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 04/15/2020] [Accepted: 04/17/2020] [Indexed: 12/13/2022] Open
Abstract
In the 1980s, after the mitochondrial DNA (mtDNA) had been sequenced, several diseases resulting from mtDNA mutations emerged. Later, numerous disorders caused by mutations in the nuclear genes encoding mitochondrial proteins were found. A group of these diseases are due to defects of mitochondrial carriers, a family of proteins named solute carrier family 25 (SLC25), that transport a variety of solutes such as the reagents of ATP synthase (ATP, ADP, and phosphate), tricarboxylic acid cycle intermediates, cofactors, amino acids, and carnitine esters of fatty acids. The disease-causing mutations disclosed in mitochondrial carriers range from point mutations, which are often localized in the substrate translocation pore of the carrier, to large deletions and insertions. The biochemical consequences of deficient transport are the compartmentalized accumulation of the substrates and dysfunctional mitochondrial and cellular metabolism, which frequently develop into various forms of myopathy, encephalopathy, or neuropathy. Examples of diseases, due to mitochondrial carrier mutations are: combined D-2- and L-2-hydroxyglutaric aciduria, carnitine-acylcarnitine carrier deficiency, hyperornithinemia-hyperammonemia-homocitrillinuria (HHH) syndrome, early infantile epileptic encephalopathy type 3, Amish microcephaly, aspartate/glutamate isoform 1 deficiency, congenital sideroblastic anemia, Fontaine progeroid syndrome, and citrullinemia type II. Here, we review all the mitochondrial carrier-related diseases known until now, focusing on the connections between the molecular basis, altered metabolism, and phenotypes of these inherited disorders.
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Affiliation(s)
- Ferdinando Palmieri
- Department of Biosciences, Biotechnologies and Biopharmaceutics, Laboratory of Biochemistry and Molecular Biology, University of Bari Aldo Moro, via E. Orabona 4, 70125 Bari, Italy;
- Correspondence: (F.P.); (M.M.); Tel.: +39-0805443323 (F.P.)
| | - Pasquale Scarcia
- Department of Biosciences, Biotechnologies and Biopharmaceutics, Laboratory of Biochemistry and Molecular Biology, University of Bari Aldo Moro, via E. Orabona 4, 70125 Bari, Italy;
| | - Magnus Monné
- Department of Biosciences, Biotechnologies and Biopharmaceutics, Laboratory of Biochemistry and Molecular Biology, University of Bari Aldo Moro, via E. Orabona 4, 70125 Bari, Italy;
- Department of Sciences, University of Basilicata, via Ateneo Lucano 10, 85100 Potenza, Italy
- Correspondence: (F.P.); (M.M.); Tel.: +39-0805443323 (F.P.)
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70
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Toleco MR, Naake T, Zhang Y, Heazlewood JL, R. Fernie A. Plant Mitochondrial Carriers: Molecular Gatekeepers That Help to Regulate Plant Central Carbon Metabolism. PLANTS 2020; 9:plants9010117. [PMID: 31963509 PMCID: PMC7020223 DOI: 10.3390/plants9010117] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 01/14/2020] [Accepted: 01/15/2020] [Indexed: 12/11/2022]
Abstract
The evolution of membrane-bound organelles among eukaryotes led to a highly compartmentalized metabolism. As a compartment of the central carbon metabolism, mitochondria must be connected to the cytosol by molecular gates that facilitate a myriad of cellular processes. Members of the mitochondrial carrier family function to mediate the transport of metabolites across the impermeable inner mitochondrial membrane and, thus, are potentially crucial for metabolic control and regulation. Here, we focus on members of this family that might impact intracellular central plant carbon metabolism. We summarize and review what is currently known about these transporters from in vitro transport assays and in planta physiological functions, whenever available. From the biochemical and molecular data, we hypothesize how these relevant transporters might play a role in the shuttling of organic acids in the various flux modes of the TCA cycle. Furthermore, we also review relevant mitochondrial carriers that may be vital in mitochondrial oxidative phosphorylation. Lastly, we survey novel experimental approaches that could possibly extend and/or complement the widely accepted proteoliposome reconstitution approach.
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Affiliation(s)
- M. Rey Toleco
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany; (M.R.T.); (T.N.); (Y.Z.)
- School of BioSciences, the University of Melbourne, Victoria 3010, Australia;
| | - Thomas Naake
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany; (M.R.T.); (T.N.); (Y.Z.)
| | - Youjun Zhang
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany; (M.R.T.); (T.N.); (Y.Z.)
- Center of Plant Systems Biology and Biotechnology, 4000 Plovdiv, Bulgaria
| | | | - Alisdair R. Fernie
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany; (M.R.T.); (T.N.); (Y.Z.)
- Center of Plant Systems Biology and Biotechnology, 4000 Plovdiv, Bulgaria
- Correspondence:
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71
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Abstract
Saccharomyces cerevisiae is one of the most popular expression systems for eukaryotic membrane proteins. Here, we describe protocols for the expression and purification of mitochondrial membrane proteins developed in our laboratory during the last 15 years. To optimize their expression in a functional form, different promoter systems as well as codon-optimization and complementation strategies were established. Purification approaches were developed which remove the membrane protein from the affinity column by specific proteolytic cleavage rather than by elution. This strategy has several important advantages, most notably improving the purity of the sample, as contaminants stay bound to the column, thus eliminating the need for a secondary purification step, such as size exclusion chromatography. This strategy also avoids dilution of the sample, which would occur as a consequence of elution, precluding the need for concentration steps, and thus preventing detergent concentration.
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Affiliation(s)
- Martin S King
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - Edmund R S Kunji
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK.
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72
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Zhukovsky MA, Filograna A, Luini A, Corda D, Valente C. Protein Amphipathic Helix Insertion: A Mechanism to Induce Membrane Fission. Front Cell Dev Biol 2019; 7:291. [PMID: 31921835 PMCID: PMC6914677 DOI: 10.3389/fcell.2019.00291] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 11/06/2019] [Indexed: 12/19/2022] Open
Abstract
One of the fundamental features of biomembranes is the ability to fuse or to separate. These processes called respectively membrane fusion and fission are central in the homeostasis of events such as those related to intracellular membrane traffic. Proteins that contain amphipathic helices (AHs) were suggested to mediate membrane fission via shallow insertion of these helices into the lipid bilayer. Here we analyze the AH-containing proteins that have been identified as essential for membrane fission and categorize them in few subfamilies, including small GTPases, Atg proteins, and proteins containing either the ENTH/ANTH- or the BAR-domain. AH-containing fission-inducing proteins may require cofactors such as additional proteins (e.g., lipid-modifying enzymes), or lipids (e.g., phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2], phosphatidic acid [PA], or cardiolipin). Both PA and cardiolipin possess a cone shape and a negative charge (-2) that favor the recruitment of the AHs of fission-inducing proteins. Instead, PtdIns(4,5)P2 is characterized by an high negative charge able to recruit basic residues of the AHs of fission-inducing proteins. Here we propose that the AHs of fission-inducing proteins contain sequence motifs that bind lipid cofactors; accordingly (K/R/H)(K/R/H)xx(K/R/H) is a PtdIns(4,5)P2-binding motif, (K/R)x6(F/Y) is a cardiolipin-binding motif, whereas KxK is a PA-binding motif. Following our analysis, we show that the AHs of many fission-inducing proteins possess five properties: (a) at least three basic residues on the hydrophilic side, (b) ability to oligomerize, (c) optimal (shallow) depth of insertion into the membrane, (d) positive cooperativity in membrane curvature generation, and (e) specific interaction with one of the lipids mentioned above. These lipid cofactors favor correct conformation, oligomeric state and optimal insertion depth. The most abundant lipid in a given organelle possessing high negative charge (more negative than -1) is usually the lipid cofactor in the fission event. Interestingly, naturally occurring mutations have been reported in AH-containing fission-inducing proteins and related to diseases such as centronuclear myopathy (amphiphysin 2), Charcot-Marie-Tooth disease (GDAP1), Parkinson's disease (α-synuclein). These findings add to the interest of the membrane fission process whose complete understanding will be instrumental for the elucidation of the pathogenesis of diseases involving mutations in the protein AHs.
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Affiliation(s)
- Mikhail A. Zhukovsky
- Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
| | | | | | - Daniela Corda
- Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
| | - Carmen Valente
- Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
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73
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The SLC25 Mitochondrial Carrier Family: Structure and Mechanism. Trends Biochem Sci 2019; 45:244-258. [PMID: 31787485 PMCID: PMC7611774 DOI: 10.1016/j.tibs.2019.11.001] [Citation(s) in RCA: 175] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 10/30/2019] [Accepted: 11/01/2019] [Indexed: 12/27/2022]
Abstract
Members of the mitochondrial carrier family (SLC25) provide the transport steps for amino acids, carboxylic acids, fatty acids, cofactors, inorganic ions, and nucleotides across the mitochondrial inner membrane and are crucial for many cellular processes. Here, we use new insights into the transport mechanism of the mitochondrial ADP/ATP carrier to examine the structure and function of other mitochondrial carriers. They all have a single substrate-binding site and two gates, which are present on either side of the membrane and involve salt-bridge networks. Transport is likely to occur by a common mechanism, in which the coordinated movement of six structural elements leads to the alternating opening and closing of the matrix or cytoplasmic side of the carriers.
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74
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Hirst J, Kunji ERS, Walker JE. Comment on "Protein assemblies ejected directly from native membranes yield complexes for mass spectrometry". Science 2019; 366:eaaw9830. [PMID: 31699909 DOI: 10.1126/science.aaw9830] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 10/09/2019] [Indexed: 02/02/2023]
Abstract
Chorev et al (Reports, 16 November 2018, p. 829) describe mass spectrometry on mitochondrial membrane proteins ionized directly from their native environment. However, the assignments made to measured masses are incorrect or inconclusive and lack experimental validation. The proteins are not in their "native" condition: They have been stripped of tightly bound lipids, and the complexes are fragmented or in physiologically irrelevant oligomeric states.
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Affiliation(s)
- Judy Hirst
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK.
| | - Edmund R S Kunji
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK.
| | - John E Walker
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK.
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75
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Chorev DS, Robinson CV. Response to Comment on “Protein assemblies ejected directly from native membranes yield complexes for mass spectrometry”. Science 2019; 366:366/6466/eaax3102. [DOI: 10.1126/science.aax3102] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Accepted: 10/09/2019] [Indexed: 01/26/2023]
Abstract
Hirst et al. claim that proteins ejected directly from mitochondrial membranes in our study are degraded, are incorrectly assigned, lack lipids, and show discrepancies with “native states” mostly obtained in detergent micelles. Here, we add further evidence in full support of our assignments and show that all complexes are either ejected intact or in known intermediate states, with core subunit interactions maintained. None are degraded or rearranged.
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Affiliation(s)
- Dror S. Chorev
- Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ, UK
| | - Carol V. Robinson
- Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ, UK
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76
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Abstract
We review the mechanisms responsible for amino acid homeostasis in Saccharomyces cerevisiae and other fungi. Amino acid homeostasis is essential for cell growth and survival. Hence, the de novo synthesis reactions, metabolic conversions, and transport of amino acids are tightly regulated. Regulation varies from nitrogen pool sensing to control by individual amino acids and takes place at the gene (transcription), protein (posttranslational modification and allostery), and vesicle (trafficking and endocytosis) levels. The pools of amino acids are controlled via import, export, and compartmentalization. In yeast, the majority of the amino acid transporters belong to the APC (amino acid-polyamine-organocation) superfamily, and the proteins couple the uphill transport of amino acids to the electrochemical proton gradient. Although high-resolution structures of yeast amino acid transporters are not available, homology models have been successfully exploited to determine and engineer the catalytic and regulatory functions of the proteins. This has led to a further understanding of the underlying mechanisms of amino acid sensing and subsequent downregulation of transport. Advances in optical microscopy have revealed a new level of regulation of yeast amino acid transporters, which involves membrane domain partitioning. The significance and the interrelationships of the latest discoveries on amino acid homeostasis are put in context.
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77
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Mitochondrial Carriers for Aspartate, Glutamate and Other Amino Acids: A Review. Int J Mol Sci 2019; 20:ijms20184456. [PMID: 31510000 PMCID: PMC6769469 DOI: 10.3390/ijms20184456] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 09/05/2019] [Accepted: 09/06/2019] [Indexed: 12/19/2022] Open
Abstract
Members of the mitochondrial carrier (MC) protein family transport various molecules across the mitochondrial inner membrane to interlink steps of metabolic pathways and biochemical processes that take place in different compartments; i.e., are localized partly inside and outside the mitochondrial matrix. MC substrates consist of metabolites, inorganic anions (such as phosphate and sulfate), nucleotides, cofactors and amino acids. These compounds have been identified by in vitro transport assays based on the uptake of radioactively labeled substrates into liposomes reconstituted with recombinant purified MCs. By using this approach, 18 human, plant and yeast MCs for amino acids have been characterized and shown to transport aspartate, glutamate, ornithine, arginine, lysine, histidine, citrulline and glycine with varying substrate specificities, kinetics, influences of the pH gradient, and capacities for the antiport and uniport mode of transport. Aside from providing amino acids for mitochondrial translation, the transport reactions catalyzed by these MCs are crucial in energy, nitrogen, nucleotide and amino acid metabolism. In this review we dissect the transport properties, phylogeny, regulation and expression levels in different tissues of MCs for amino acids, and summarize the main structural aspects known until now about MCs. The effects of their disease-causing mutations and manipulation of their expression levels in cells are also considered as clues for understanding their physiological functions.
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78
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Dynamics and interactions of AAC3 in DPC are not functionally relevant. Nat Struct Mol Biol 2019; 25:745-747. [PMID: 30177758 DOI: 10.1038/s41594-018-0127-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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79
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Ruprecht JJ, Kunji ER. Structural changes in the transport cycle of the mitochondrial ADP/ATP carrier. Curr Opin Struct Biol 2019; 57:135-144. [PMID: 31039524 PMCID: PMC6700394 DOI: 10.1016/j.sbi.2019.03.029] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2019] [Revised: 03/15/2019] [Accepted: 03/20/2019] [Indexed: 11/27/2022]
Abstract
The mitochondrial ADP/ATP carrier, also called adenine nucleotide translocase, accomplishes one of the most important transport activities in eukaryotic cells, importing ADP into the mitochondrial matrix for ATP synthesis, and exporting ATP to fuel cellular activities. In the transport cycle, the carrier changes between a cytoplasmic and matrix state, in which the central substrate binding site is alternately accessible to these compartments. A structure of a cytoplasmic state was known, but recently, a structure of a matrix-state in complex with bongkrekic acid was solved. Comparison of the two states explains the function of highly conserved sequence features and reveals that the transport mechanism is unique, involving the coordinated movement of six dynamic elements around a central translocation pathway.
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Affiliation(s)
- Jonathan J Ruprecht
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0XY, UK.
| | - Edmund Rs Kunji
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0XY, UK.
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80
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Gorgoglione R, Porcelli V, Santoro A, Daddabbo L, Vozza A, Monné M, Di Noia MA, Palmieri L, Fiermonte G, Palmieri F. The human uncoupling proteins 5 and 6 (UCP5/SLC25A14 and UCP6/SLC25A30) transport sulfur oxyanions, phosphate and dicarboxylates. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1860:724-733. [PMID: 31356773 DOI: 10.1016/j.bbabio.2019.07.010] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 06/27/2019] [Accepted: 07/25/2019] [Indexed: 01/07/2023]
Abstract
The human genome encodes 53 members of the solute carrier family 25 (SLC25), also called the mitochondrial carrier family. In this work, two members of this family, UCP5 (BMCP1, brain mitochondrial carrier protein 1 encoded by SLC25A14) and UCP6 (KMCP1, kidney mitochondrial carrier protein 1 encoded by SLC25A30) have been thoroughly characterized biochemically. They were overexpressed in bacteria, purified and reconstituted in phospholipid vesicles. Their transport properties and kinetic parameters demonstrate that UCP5 and UCP6 transport inorganic anions (sulfate, sulfite, thiosulfate and phosphate) and, to a lesser extent, a variety of dicarboxylates (e.g. malonate, malate and citramalate) and, even more so, aspartate and (only UCP5) glutamate and tricarboxylates. Both carriers catalyzed a fast counter-exchange transport and a very low uniport of substrates. Transport was saturable and inhibited by mercurials and other mitochondrial carrier inhibitors at various degrees. The transport affinities of UCP5 and UCP6 were higher for sulfate and thiosulfate than for any other substrate, whereas the specific activity of UCP5 was much higher than that of UCP6. It is proposed that a main physiological role of UCP5 and UCP6 is to catalyze the export of sulfite and thiosulfate (the H2S degradation products) from the mitochondria, thereby modulating the level of the important signal molecule H2S.
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Affiliation(s)
- Ruggiero Gorgoglione
- Department of Biosciences, Biotechnologies and Biopharmaceutics, Laboratory of Biochemistry and Molecular Biology, University of Bari Aldo Moro, Via E. Orabona 4, 70125 Bari, Italy
| | - Vito Porcelli
- Department of Biosciences, Biotechnologies and Biopharmaceutics, Laboratory of Biochemistry and Molecular Biology, University of Bari Aldo Moro, Via E. Orabona 4, 70125 Bari, Italy
| | - Antonella Santoro
- Department of Biosciences, Biotechnologies and Biopharmaceutics, Laboratory of Biochemistry and Molecular Biology, University of Bari Aldo Moro, Via E. Orabona 4, 70125 Bari, Italy
| | - Lucia Daddabbo
- Department of Biosciences, Biotechnologies and Biopharmaceutics, Laboratory of Biochemistry and Molecular Biology, University of Bari Aldo Moro, Via E. Orabona 4, 70125 Bari, Italy
| | - Angelo Vozza
- Department of Biosciences, Biotechnologies and Biopharmaceutics, Laboratory of Biochemistry and Molecular Biology, University of Bari Aldo Moro, Via E. Orabona 4, 70125 Bari, Italy; Center of Excellence in Comparative Genomics, University of Bari, via Orabona 4, 70125 Bari, Italy
| | - Magnus Monné
- Department of Biosciences, Biotechnologies and Biopharmaceutics, Laboratory of Biochemistry and Molecular Biology, University of Bari Aldo Moro, Via E. Orabona 4, 70125 Bari, Italy; Department of Sciences, University of Basilicata, Via Ateneo Lucano 10, 85100 Potenza, Italy
| | - Maria Antonietta Di Noia
- Department of Biosciences, Biotechnologies and Biopharmaceutics, Laboratory of Biochemistry and Molecular Biology, University of Bari Aldo Moro, Via E. Orabona 4, 70125 Bari, Italy
| | - Luigi Palmieri
- Department of Biosciences, Biotechnologies and Biopharmaceutics, Laboratory of Biochemistry and Molecular Biology, University of Bari Aldo Moro, Via E. Orabona 4, 70125 Bari, Italy; Center of Excellence in Comparative Genomics, University of Bari, via Orabona 4, 70125 Bari, Italy; CNR Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), 70126 Bari, Italy
| | - Giuseppe Fiermonte
- Department of Biosciences, Biotechnologies and Biopharmaceutics, Laboratory of Biochemistry and Molecular Biology, University of Bari Aldo Moro, Via E. Orabona 4, 70125 Bari, Italy; Center of Excellence in Comparative Genomics, University of Bari, via Orabona 4, 70125 Bari, Italy.
| | - Ferdinando Palmieri
- Department of Biosciences, Biotechnologies and Biopharmaceutics, Laboratory of Biochemistry and Molecular Biology, University of Bari Aldo Moro, Via E. Orabona 4, 70125 Bari, Italy; Center of Excellence in Comparative Genomics, University of Bari, via Orabona 4, 70125 Bari, Italy; CNR Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), 70126 Bari, Italy
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81
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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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82
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Abstract
Uncoupling protein 1 (UCP1) is an integral protein of the inner mitochondrial membrane (IMM) that is expressed specifically in brown and beige fat depots. UCP1 is responsible for the production of heat to control core body temperature, the regulation of fat metabolism, and the energy balance. As an uncoupling protein, UCP1 transports H+ across the IMM in presence of long-chain fatty acids (FA), which makes brown fat mitochondria produce heat at the expense of ATP. However, the exact mechanism of UCP1 action has remained difficult to elucidate, because direct methods for studying currents generated by UCP1 were unavailable. Recently, the patch-clamp technique was successfully applied to brown and beige fat mitochondria to directly study H+ currents across the IMM and characterize UCP1 function. A new model of the UCP1 mechanism was proposed based on the patch-clamp analysis. In this model, both FA anions (FA-) and H+ are transport substrates of UCP1, and UCP1 operates as a non-canonical FA-/H+ symporter. Here, we summarize recent findings obtained with the patch-clamp technique that describe how UCP1 can transport not only H+ but also FA-.
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83
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Yi Q, Li Q, Yao S, Chen Y, Guan MX, Cang X. Molecular dynamics simulations on apo ADP/ATP carrier shed new lights on the featured motif of the mitochondrial carriers. Mitochondrion 2019; 47:94-102. [PMID: 31129042 DOI: 10.1016/j.mito.2019.05.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 04/30/2019] [Accepted: 05/20/2019] [Indexed: 02/04/2023]
Abstract
The ADP/ATP carrier (AAC) is a transporter responsible for the equal molar exchange of cytosolic ADP and ATP synthesized within mitochondrial matrix across the mitochondrial membrane. Its primary structure consists of three homologous repeats, and each repeat contains a conserved motif that is shared by all members of the mitochondrial carrier family (MCF). Although these MCF motif residues cluster together in the crystal structure of AAC, detailed analyses on the interactions among the motif residues are still limited. In the present study, all-atom molecular dynamics (MD) simulations of up to 10 μs have been carried out on AAC, and interactions and structural dynamics of the MCF motif residues have been specifically investigated. Our simulations have revealed: i) a very asymmetrical electrostatic network at the bottom of the pocket of apo AAC, ii) the asymmetrical interactions between the Pro kink region and the [YWF][KR] G motif in three repeats, iii) the role of the conserved Arg residues in stabilizing the C-ends of the odd-numbered helices, iv) the structural change of the [YWF][KR] G motif and its potential involvement in substrate translocation process. Our results highlight the asymmetry of the MCF residues in the three repeats, which might contribute to the ability of the carriers to transport the asymmetrical substrates. Our observations provide microscopic basis for further research on the translocation mechanism of mitochondrial carriers.
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Affiliation(s)
- Qiuzi Yi
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, China; Institute of Genetics, Zhejiang University and Department of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Qiang Li
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, China; Institute of Genetics, Zhejiang University and Department of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Shihao Yao
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, China; Institute of Genetics, Zhejiang University and Department of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Ye Chen
- School of Information and Electric Engineering, China University of Mining and Technology, Xuzhou, Jiangsu 221008, China
| | - Min-Xin Guan
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, China; Institute of Genetics, Zhejiang University and Department of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Xiaohui Cang
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, China; Institute of Genetics, Zhejiang University and Department of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.
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84
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The mitochondrial citrate carrier in Yarrowia lipolytica: Its identification, characterization and functional significance for the production of citric acid. Metab Eng 2019; 54:264-274. [PMID: 31071446 DOI: 10.1016/j.ymben.2019.05.002] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Revised: 04/30/2019] [Accepted: 05/03/2019] [Indexed: 12/21/2022]
Abstract
Mitochondrial citrate carrier plays a central role in exporting acetyl-CoA in the form of citrate from mitochondria to cytosol thereby connecting carbohydrate catabolism and lipogenesis. In this study, Yarrowia lipolytica mitochondrial citrate carrier was functionally defined and characterized. Firstly, deletion of Y. lipolytica YlCTP1 and YlYHM2 genes coding putative tricarboxylate mitochondrial carriers were performed. ΔYlctp1 strain did not differ significantly from wild type strain in terms of growth rate, organic acids and lipid production. In contrast, ΔYlyhm2 strain did not grow in liquid citrate-containing minimal medium. Moreover, in glucose-containing lipogenic medium YlYHM2 null mutant strain did not produce citric acid; the production of isocitric acid and lipids were decreased. Reintroduction of YlYHM2 gene as well as heterologous expression of Aspergillus niger gene AnYHM2 into ΔYlyhm2 strain restored the growth in minimal citrate medium and even enhanced citric acid production by 45% in both variants compared with wild type strain during test tube cultivation. Mitochondrial extracts isolated from YlYHM2 null mutant and wild type strain were incorporated into liposomes; citrate/citrate and α-ketoglutarate/α-ketoglutarate homoexchange activities were reduced by 87% and 40% in ΔYlyhm2 strain, respectively, compared with the wild type, whereas citratein/α-ketoglutarateout and α-ketoglutaratein/citrateout heteroexchanges were decreased by 87% and 95%, respectively. YlYhm2p was expressed in Escherichia coli, purified and reconstituted into liposomes. Besides high efficiency to citrate and α-ketoglutarate transport, YlYhm2p also transported oxaloacetate, succinate, fumarate, and to a much lesser extent, aconitate, malate, isocitrate, oxoadipate, and glutamate. The activity of reconstituted YlYhm2p was inhibited strongly by SH-blocking reagents, pyridoxal-5'-phosphate, and partly by N-ethylmaleimide. Co-expression of YlYHM2 and adenosine monophosphate deaminase YlAMPD genes resulted in the production of 49.7 g/L of citric acid during test tube cultivation, whereas wild type strain accumulated 30.1 g/L of citric acid. Large-scale cultivation in bioreactor of the engineered strain resulted in 97.1 g/L of citric acid production with a process selectivity of 94.2% and an overall citric acid yield of 0.5 g/g. The maximal specific rate of citric acid synthesis was 0.93 g/L/h. Therefore, the physiological role of YlYhm2p in glucose-containing medium is to catalyze both import of citrate into mitochondria for catabolic reactions and export of citrate as a source of acetyl-CoA from mitochondria. Possible shuttles for citrate exporting are discussed. Moreover, for the first time evidence has been given for the improvement of TCA cycle intermediate production by manipulation of a gene coding a mitochondrial carrier.
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85
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Liu Y, Wang X, Coyne LP, Yang Y, Qi Y, Middleton FA, Chen XJ. Mitochondrial carrier protein overloading and misfolding induce aggresomes and proteostatic adaptations in the cytosol. Mol Biol Cell 2019; 30:1272-1284. [PMID: 30893019 PMCID: PMC6724602 DOI: 10.1091/mbc.e19-01-0046] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Previous studies in yeast showed that mitochondrial stressors not directly targeting the protein import machinery can cause mitochondrial precursor overaccumulation stress (mPOS) in the cytosol independent of bioenergetics. Here, we demonstrate mPOS and stress responses in human cells. We show that overloading of mitochondrial membrane carrier, but not matrix proteins, is sufficient to induce cytosolic aggresomes and apoptosis. The aggresomes appear to triage unimported mitochondrial proteins. Interestingly, expression of highly unstable mutant variants of the mitochondrial carrier protein, Ant1, also induces aggresomes despite a greater than 20-fold reduction in protein level compared to wild type. Thus, overloading of the protein import machinery, rather than protein accumulation, is critical for aggresome induction. The data suggest that the import of mitochondrial proteins is saturable and that the cytosol is limited in degrading unimported mitochondrial proteins. In addition, we found that EGR1, eEF1a, and ubiquitin C are up-regulated by Ant1 overloading. These proteins are known to promote autophagy, protein targeting to aggresomes, and the processing of protein aggregates, respectively. Finally, we found that overexpression of the misfolded variants of Ant1 induces additional cytosolic responses including proteasomal activation. In summary, our work captured a profound effect of unimported mitochondrial proteins on cytosolic proteostasis and revealed multiple anti-mPOS mechanisms in human cells.
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Affiliation(s)
- Yaxin Liu
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, NY 13210
| | - Xiaowen Wang
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, NY 13210
| | - Liam P Coyne
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, NY 13210
| | - Yuan Yang
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, NY 13210
| | - Yue Qi
- Department of Pathology, State University of New York Upstate Medical University, Syracuse, NY 13210
| | - Frank A Middleton
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, NY 13210
| | - Xin Jie Chen
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, NY 13210.,Department of Neuroscience and Physiology, State University of New York Upstate Medical University, Syracuse, NY 13210
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86
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Enkavi G, Javanainen M, Kulig W, Róg T, Vattulainen I. Multiscale Simulations of Biological Membranes: The Challenge To Understand Biological Phenomena in a Living Substance. Chem Rev 2019; 119:5607-5774. [PMID: 30859819 PMCID: PMC6727218 DOI: 10.1021/acs.chemrev.8b00538] [Citation(s) in RCA: 173] [Impact Index Per Article: 34.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
![]()
Biological
membranes are tricky to investigate. They are complex
in terms of molecular composition and structure, functional
over a wide range of time scales, and characterized
by nonequilibrium conditions. Because of all of these
features, simulations are a great technique to study biomembrane
behavior. A significant part of the functional processes
in biological membranes takes place at the molecular
level; thus computer simulations are the method of
choice to explore how their properties emerge from specific
molecular features and how the interplay among the numerous
molecules gives rise to function over spatial and
time scales larger than the molecular ones. In this
review, we focus on this broad theme. We discuss the current
state-of-the-art of biomembrane simulations that, until
now, have largely focused on a rather narrow picture
of the complexity of the membranes. Given this, we
also discuss the challenges that we should unravel in the
foreseeable future. Numerous features such as the actin-cytoskeleton
network, the glycocalyx network, and nonequilibrium
transport under ATP-driven conditions have so far
received very little attention; however, the potential
of simulations to solve them would be exceptionally high. A
major milestone for this research would be that one day
we could say that computer simulations genuinely research
biological membranes, not just lipid bilayers.
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Affiliation(s)
- Giray Enkavi
- Department of Physics , University of Helsinki , P.O. Box 64, FI-00014 Helsinki , Finland
| | - Matti Javanainen
- Department of Physics , University of Helsinki , P.O. Box 64, FI-00014 Helsinki , Finland.,Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences , Flemingovo naḿesti 542/2 , 16610 Prague , Czech Republic.,Computational Physics Laboratory , Tampere University , P.O. Box 692, FI-33014 Tampere , Finland
| | - Waldemar Kulig
- Department of Physics , University of Helsinki , P.O. Box 64, FI-00014 Helsinki , Finland
| | - Tomasz Róg
- Department of Physics , University of Helsinki , P.O. Box 64, FI-00014 Helsinki , Finland.,Computational Physics Laboratory , Tampere University , P.O. Box 692, FI-33014 Tampere , Finland
| | - Ilpo Vattulainen
- Department of Physics , University of Helsinki , P.O. Box 64, FI-00014 Helsinki , Finland.,Computational Physics Laboratory , Tampere University , P.O. Box 692, FI-33014 Tampere , Finland.,MEMPHYS-Center for Biomembrane Physics
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87
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Hedger G, Koldsø H, Chavent M, Siebold C, Rohatgi R, Sansom MSP. Cholesterol Interaction Sites on the Transmembrane Domain of the Hedgehog Signal Transducer and Class F G Protein-Coupled Receptor Smoothened. Structure 2019; 27:549-559.e2. [PMID: 30595453 PMCID: PMC6408332 DOI: 10.1016/j.str.2018.11.003] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 09/28/2018] [Accepted: 11/02/2018] [Indexed: 12/12/2022]
Abstract
Transduction of Hedgehog signals across the plasma membrane is facilitated by the class F G-protein-coupled-receptor (GPCR) Smoothened (SMO). Recent studies suggest that SMO is modulated via interactions of its transmembrane (TM) domain with cholesterol. We apply molecular dynamics simulations of SMO embedded in cholesterol containing lipid bilayers, revealing a direct interaction of cholesterol with the TM domain at regions distinct from those observed in class A GPCRs. In particular the extracellular tips of helices TM2 and TM3 form a well-defined cholesterol interaction site. Potential of mean force calculations yield a free energy landscape for cholesterol binding. Alongside analysis of equilibrium cholesterol occupancy, this reveals the existence of a dynamic "greasy patch" interaction with the TM domain of SMO, which may be compared with previously identified lipid interaction sites on other membrane proteins. These predictions provide molecular-level insights into cholesterol interactions with a class F GPCR, suggesting potential druggable sites.
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Affiliation(s)
- George Hedger
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Heidi Koldsø
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Matthieu Chavent
- Institut de Pharmacologie et de Biologie Structurale IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Christian Siebold
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Rajat Rohatgi
- Departments of Biochemistry and Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Mark S P Sansom
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
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88
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Ogunbona OB, Claypool SM. Emerging Roles in the Biogenesis of Cytochrome c Oxidase for Members of the Mitochondrial Carrier Family. Front Cell Dev Biol 2019; 7:3. [PMID: 30766870 PMCID: PMC6365663 DOI: 10.3389/fcell.2019.00003] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 01/10/2019] [Indexed: 12/11/2022] Open
Abstract
The mitochondrial carrier family (MCF) is a group of transport proteins that are mostly localized to the inner mitochondrial membrane where they facilitate the movement of various solutes across the membrane. Although these carriers represent potential targets for therapeutic application and are repeatedly associated with human disease, research on the MCF has not progressed commensurate to their physiologic and pathophysiologic importance. Many of the 53 MCF members in humans are orphans and lack known transport substrates. Even for the relatively well-studied members of this family, such as the ADP/ATP carrier and the uncoupling protein, there exist fundamental gaps in our understanding of their biological roles including a clear rationale for the existence of multiple isoforms. Here, we briefly review this important family of mitochondrial carriers, provide a few salient examples of their diverse metabolic roles and disease associations, and then focus on an emerging link between several distinct MCF members, including the ADP/ATP carrier, and cytochrome c oxidase biogenesis. As the ADP/ATP carrier is regarded as the paradigm of the entire MCF, its newly established role in regulating translation of the mitochondrial genome highlights that we still have a lot to learn about these metabolite transporters.
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Affiliation(s)
- Oluwaseun B. Ogunbona
- Department of Physiology, School of Medicine, Johns Hopkins University, Baltimore, MD, United States
- Department of Pathology & Laboratory Medicine, School of Medicine, Emory University, Atlanta, GA, United States
| | - Steven M. Claypool
- Department of Physiology, School of Medicine, Johns Hopkins University, Baltimore, MD, United States
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89
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Ruprecht JJ, King MS, Zögg T, Aleksandrova AA, Pardon E, Crichton PG, Steyaert J, Kunji ERS. The Molecular Mechanism of Transport by the Mitochondrial ADP/ATP Carrier. Cell 2019; 176:435-447.e15. [PMID: 30611538 PMCID: PMC6349463 DOI: 10.1016/j.cell.2018.11.025] [Citation(s) in RCA: 185] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Revised: 09/25/2018] [Accepted: 11/16/2018] [Indexed: 11/30/2022]
Abstract
Mitochondrial ADP/ATP carriers transport ADP into the mitochondrial matrix for ATP synthesis, and ATP out to fuel the cell, by cycling between cytoplasmic-open and matrix-open states. The structure of the cytoplasmic-open state is known, but it has proved difficult to understand the transport mechanism in the absence of a structure in the matrix-open state. Here, we describe the structure of the matrix-open state locked by bongkrekic acid bound in the ADP/ATP-binding site at the bottom of the central cavity. The cytoplasmic side of the carrier is closed by conserved hydrophobic residues, and a salt bridge network, braced by tyrosines. Glycine and small amino acid residues allow close-packing of helices on the matrix side. Uniquely, the carrier switches between states by rotation of its three domains about a fulcrum provided by the substrate-binding site. Because these features are highly conserved, this mechanism is likely to apply to the whole mitochondrial carrier family. Video Abstract
Structure of the matrix-open state of the mitochondrial ADP/ATP carrier solved The inhibitor bongkrekic acid locks the state by occupying the substrate-binding site Conformational changes during transport are highly dynamic, using six mobile elements Roles of all conserved sequence features in mitochondrial carriers are now explained
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Affiliation(s)
- Jonathan J Ruprecht
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0XY, UK.
| | - Martin S King
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0XY, UK
| | - Thomas Zögg
- VIB-VUB Center for Structural Biology, VIB, Pleinlaan 2, 1050 Brussels, Belgium; Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Antoniya A Aleksandrova
- Computational Structural Biology Section, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD 20892, USA
| | - Els Pardon
- VIB-VUB Center for Structural Biology, VIB, Pleinlaan 2, 1050 Brussels, Belgium; Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Paul G Crichton
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0XY, UK
| | - Jan Steyaert
- VIB-VUB Center for Structural Biology, VIB, Pleinlaan 2, 1050 Brussels, Belgium; Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Edmund R S Kunji
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0XY, UK.
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90
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Structural biology and structure–function relationships of membrane proteins. Biochem Soc Trans 2018; 47:47-61. [DOI: 10.1042/bst20180269] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 10/22/2018] [Accepted: 10/29/2018] [Indexed: 01/02/2023]
Abstract
Abstract
The study of structure–function relationships of membrane proteins (MPs) has been one of the major goals in the field of structural biology. Many Noble Prizes regarding remarkable accomplishments in MP structure determination and biochemistry have been awarded over the last few decades. Mutations or improper folding of these proteins are associated with numerous serious illnesses. Therefore, as important drug targets, the study of their primary sequence and three-dimensional fold, combined with cell-based assays, provides vital information about their structure–function relationships. Today, this information is vital to drug discovery and medicine. In the last two decades, many have been the technical advances and breakthroughs in the field of MP structural biology that have contributed to an exponential growth in the number of unique MP structures in the Protein Data Bank. Nevertheless, given the medical importance and many unanswered questions, it will never be an excess of MP structures, regardless of the method used. Owing to the extension of the field, in this brief review, we will only focus on structure–function relationships of the three most significant pharmaceutical classes: G protein-coupled receptors, ion channels and transporters.
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91
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Mulkidjanian AY, Shalaeva DN, Lyamzaev KG, Chernyak BV. Does Oxidation of Mitochondrial Cardiolipin Trigger a Chain of Antiapoptotic Reactions? BIOCHEMISTRY (MOSCOW) 2018; 83:1263-1278. [PMID: 30472963 DOI: 10.1134/s0006297918100115] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Oxidative stress causes selective oxidation of cardiolipin (CL), a four-tail lipid specific for the inner mitochondrial membrane. Interaction with oxidized CL transforms cytochrome c into peroxidase capable of oxidizing even more CL molecules. Ultimately, this chain of events leads to the pore formation in the outer mitochondrial membrane and release of mitochondrial proteins, including cytochrome c, into the cytoplasm. In the cytoplasm, cytochrome c promotes apoptosome assembly that triggers apoptosis (programmed cell death). Because of this amplification cascade, even an occasional oxidation of a single CL molecule by endogenously formed reactive oxygen species (ROS) might cause cell death, unless the same CL oxidation triggers a separate chain of antiapoptotic reactions that would prevent the CL-mediated apoptotic cascade. Here, we argue that the key function of CL in mitochondria and other coupling membranes is to prevent proton leak along the interface of interacting membrane proteins. Therefore, CL oxidation should increase proton permeability through the CL-rich clusters of membrane proteins (CL islands) and cause a drop in the mitochondrial membrane potential (MMP). On one hand, the MMP drop should hinder ROS generation and further CL oxidation in the entire mitochondrion. On the other hand, it is known to cause rapid fission of the mitochondrial network and formation of many small mitochondria, only some of which would contain oxidized CL islands. The fission of mitochondrial network would hinder apoptosome formation by preventing cytochrome c release from healthy mitochondria, so that slowly working protein quality control mechanisms would have enough time to eliminate mitochondria with the oxidized CL. Because of these two oppositely directed regulatory pathways, both triggered by CL oxidation, the fate of the cell appears to be determined by the balance between the CL-mediated proapoptotic and antiapoptotic reactions. Since this balance depends on the extent of CL oxidation, mitochondria-targeted antioxidants might be able to ensure cell survival in many pathologies by preventing CL oxidation.
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Affiliation(s)
- A Y Mulkidjanian
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia. .,Lomonosov Moscow State University, School of Bioengineering and Bioinformatics, Moscow, 119991, Russia.,Osnabrueck University, Department of Physics, 49069 Osnabrueck, Germany
| | - D N Shalaeva
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia
| | - K G Lyamzaev
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia
| | - B V Chernyak
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia
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92
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Harborne SPD, Kunji ERS. Calcium-regulated mitochondrial ATP-Mg/P i carriers evolved from a fusion of an EF-hand regulatory domain with a mitochondrial ADP/ATP carrier-like domain. IUBMB Life 2018; 70:1222-1232. [PMID: 30281880 PMCID: PMC6283063 DOI: 10.1002/iub.1931] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 07/19/2018] [Accepted: 07/19/2018] [Indexed: 02/02/2023]
Abstract
The mitochondrial ATP-Mg/Pi carrier is responsible for the calcium-dependent regulation of adenosine nucleotide concentrations in the mitochondrial matrix, which allows mitochondria to respond to changing energy requirements of the cell. The carrier is expressed in mitochondria of fungi, plants and animals and belongs to the family of mitochondrial carriers. The carrier is unusual as it consists of three separate domains: (i) an N-terminal regulatory domain with four calcium-binding EF-hands similar to calmodulin, (ii) a loop domain containing an amphipathic α-helix and (iii) a mitochondrial carrier domain related to the mitochondrial ADP/ATP carrier. This striking example of three domains coming together from different origins to provide new functions represents an interesting quirk of evolution. In this review, we outline how the carrier was identified and how its physiological role was established with a focus on human isoforms. We exploit the sequence and structural information of the domains to explore the similarities and differences to their closest counterparts; mitochondrial ADP/ATP carriers and proteins with four EF-hands. We discuss how their combined function has led to a mechanism for calcium-regulated transport of adenosine nucleotides. Finally, we compare the ATP-Mg/Pi carrier with the mitochondrial aspartate/glutamate carrier, the only other mitochondrial carrier regulated by calcium, and we will argue that they have arisen by convergent rather than divergent evolution. © 2018 The Authors. IUBMB Life published by Wiley Periodicals, Inc. on behalf of International Union of Biochemistry and Molecular Biology, 70(12):1222-1232, 2018.
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Affiliation(s)
- Steven P. D. Harborne
- School of Biomedical Sciences and Astbury Centre for Structural Molecular BiologyUniversity of LeedsLeedsLS2 9JTUK
| | - Edmund R. S. Kunji
- Medical Research Council Mitochondrial Biology UnitUniversity of CambridgeCambridgeCB2 0XYUK
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93
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Jing Y, Niu Y, Liu C, Zen K, Li D. In silico identification of lipid-binding α helices of uncoupling protein 1. Biomed Rep 2018; 9:313-317. [PMID: 30233783 PMCID: PMC6142039 DOI: 10.3892/br.2018.1133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Accepted: 07/19/2018] [Indexed: 11/29/2022] Open
Abstract
Uncoupling protein 1 (UCP1) located at the mitochondrial inner membrane serves an important role in adaptive non-shivering thermogenesis. Previous data has demonstrated that membrane lipids regulate the biological functions of membrane proteins. However, how mitochondrial lipids interact with UCP1 still remains elusive. In this study, the interactions between UCP1 and membrane lipids were investigated, using bioinformatic approaches due to the limitations associated with experimental techniques. A total of 8 UCP1 peptide regions with α-helices were identified and related to functional sites of UCP1. These were all novel peptide sequences compared with the known protein-lipid interactions. Among several types of UCP1-binding molecules, cardiolipin appeared to serve as a key interacting molecule of the 8 lipid-binding α-helix regions of UCP1. Two cardiolipin-binding lysines (K175 and K269) of UCP1 may be crucial for this UCP1-cardiolipin recognition and UCP1 function. The present findings provide novel insight into the associations of UCP1 with lipids and the potential drug targets in UCP1-associated diseases.
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Affiliation(s)
- Ying Jing
- State Key Laboratory of Pharmaceutical Biotechnology, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, Nanjing Advanced Institute for Life Sciences (NAILS), School of Life Sciences, Nanjing University, Nanjing, Jiangsu 210023, P.R. China
| | - Yahan Niu
- State Key Laboratory of Pharmaceutical Biotechnology, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, Nanjing Advanced Institute for Life Sciences (NAILS), School of Life Sciences, Nanjing University, Nanjing, Jiangsu 210023, P.R. China
| | - Chang Liu
- State Key Laboratory of Pharmaceutical Biotechnology, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, Nanjing Advanced Institute for Life Sciences (NAILS), School of Life Sciences, Nanjing University, Nanjing, Jiangsu 210023, P.R. China
| | - Ke Zen
- State Key Laboratory of Pharmaceutical Biotechnology, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, Nanjing Advanced Institute for Life Sciences (NAILS), School of Life Sciences, Nanjing University, Nanjing, Jiangsu 210023, P.R. China
| | - Donghai Li
- State Key Laboratory of Pharmaceutical Biotechnology, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, Nanjing Advanced Institute for Life Sciences (NAILS), School of Life Sciences, Nanjing University, Nanjing, Jiangsu 210023, P.R. China
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94
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Ježek P, Holendová B, Garlid KD, Jabůrek M. Mitochondrial Uncoupling Proteins: Subtle Regulators of Cellular Redox Signaling. Antioxid Redox Signal 2018; 29:667-714. [PMID: 29351723 PMCID: PMC6071544 DOI: 10.1089/ars.2017.7225] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
SIGNIFICANCE Mitochondria are the energetic, metabolic, redox, and information signaling centers of the cell. Substrate pressure, mitochondrial network dynamics, and cristae morphology state are integrated by the protonmotive force Δp or its potential component, ΔΨ, which are attenuated by proton backflux into the matrix, termed uncoupling. The mitochondrial uncoupling proteins (UCP1-5) play an eminent role in the regulation of each of the mentioned aspects, being involved in numerous physiological events including redox signaling. Recent Advances: UCP2 structure, including purine nucleotide and fatty acid (FA) binding sites, strongly support the FA cycling mechanism: UCP2 expels FA anions, whereas uncoupling is achieved by the membrane backflux of protonated FA. Nascent FAs, cleaved by phospholipases, are preferential. The resulting Δp dissipation decreases superoxide formation dependent on Δp. UCP-mediated antioxidant protection and its impairment are expected to play a major role in cell physiology and pathology. Moreover, UCP2-mediated aspartate, oxaloacetate, and malate antiport with phosphate is expected to alter metabolism of cancer cells. CRITICAL ISSUES A wide range of UCP antioxidant effects and participations in redox signaling have been reported; however, mechanisms of UCP activation are still debated. Switching off/on the UCP2 protonophoretic function might serve as redox signaling either by employing/releasing the extra capacity of cell antioxidant systems or by directly increasing/decreasing mitochondrial superoxide sources. Rapid UCP2 degradation, FA levels, elevation of purine nucleotides, decreased Mg2+, or increased pyruvate accumulation may initiate UCP-mediated redox signaling. FUTURE DIRECTIONS Issues such as UCP2 participation in glucose sensing, neuronal (synaptic) function, and immune cell activation should be elucidated. Antioxid. Redox Signal. 29, 667-714.
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Affiliation(s)
- Petr Ježek
- 1 Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences , Prague, Czech Republic
| | - Blanka Holendová
- 1 Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences , Prague, Czech Republic
| | - Keith D Garlid
- 2 UCLA Cardiovascular Research Laboratory, David Geffen School of Medicine at UCLA , Los Angeles, California
| | - Martin Jabůrek
- 1 Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences , Prague, Czech Republic
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95
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King MS, Crichton PG, Ruprecht JJ, Kunji ERS. Concerns with yeast mitochondrial ADP/ATP carrier's integrity in DPC. Nat Struct Mol Biol 2018; 25:747-749. [PMID: 30177757 DOI: 10.1038/s41594-018-0125-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Martin S King
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - Paul G Crichton
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK.,Biomedical Research Centre, Norwich Medical School, University of East Anglia, Norwich Research Park, Norwich, UK
| | - Jonathan J Ruprecht
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - Edmund R S Kunji
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK.
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96
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Hofherr A, Seger C, Fitzpatrick F, Busch T, Michel E, Luan J, Osterried L, Linden F, Kramer-Zucker A, Wakimoto B, Schütze C, Wiedemann N, Artati A, Adamski J, Walz G, Kunji ERS, Montell C, Watnick T, Köttgen M. The mitochondrial transporter SLC25A25 links ciliary TRPP2 signaling and cellular metabolism. PLoS Biol 2018; 16:e2005651. [PMID: 30080851 PMCID: PMC6095617 DOI: 10.1371/journal.pbio.2005651] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 08/16/2018] [Accepted: 07/27/2018] [Indexed: 02/02/2023] Open
Abstract
Cilia are organelles specialized in movement and signal transduction. The ciliary transient receptor potential ion channel polycystin-2 (TRPP2) controls elementary cilia-mediated physiological functions ranging from male fertility and kidney development to left-right patterning. However, the molecular components translating TRPP2 channel-mediated Ca2+ signals into respective physiological functions are unknown. Here, we show that the Ca2+-regulated mitochondrial ATP-Mg/Pi solute carrier 25 A 25 (SLC25A25) acts downstream of TRPP2 in an evolutionarily conserved metabolic signaling pathway. We identify SLC25A25 as an essential component in this cilia-dependent pathway using a genome-wide forward genetic screen in Drosophila melanogaster, followed by a targeted analysis of SLC25A25 function in zebrafish left-right patterning. Our data suggest that TRPP2 ion channels regulate mitochondrial SLC25A25 transporters via Ca2+ establishing an evolutionarily conserved molecular link between ciliary signaling and mitochondrial metabolism.
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Affiliation(s)
- Alexis Hofherr
- Renal Division, Department of Medicine, Medical Center – University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
- Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg im Breisgau, Germany
- Faculty of Biology, University of Freiburg, Freiburg im Breisgau, Germany
- * E-mail: (AH); (MK)
| | - Claudia Seger
- Renal Division, Department of Medicine, Medical Center – University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
| | - Fiona Fitzpatrick
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge, United Kingdom
| | - Tilman Busch
- Renal Division, Department of Medicine, Medical Center – University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
| | - Elisabeth Michel
- Renal Division, Department of Medicine, Medical Center – University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
| | - Jingting Luan
- Renal Division, Department of Medicine, Medical Center – University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
| | - Lea Osterried
- Renal Division, Department of Medicine, Medical Center – University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
| | - Frieder Linden
- Renal Division, Department of Medicine, Medical Center – University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
| | - Albrecht Kramer-Zucker
- Renal Division, Department of Medicine, Medical Center – University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
| | - Barbara Wakimoto
- Department of Biology, University of Washington, Seattle, Washington, United States of America
| | - Conny Schütze
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
| | - Nils Wiedemann
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
- BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg im Breisgau, Germany
| | - Anna Artati
- Institute of Experimental Genetics, Genome Analysis Center, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
| | - Jerzy Adamski
- Institute of Experimental Genetics, Genome Analysis Center, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
- Lehrstuhl für Experimentelle Genetik, Technische Universität München, Freising-Weihenstephan, Germany
- German Center for Diabetes Research (DZD), München-Neuherberg, Germany
| | - Gerd Walz
- Renal Division, Department of Medicine, Medical Center – University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
- BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg im Breisgau, Germany
| | - Edmund R. S. Kunji
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge, United Kingdom
| | - Craig Montell
- Neuroscience Research Institute and Department of Molecular, Cellular and Developmental Biology, University of California Santa Barbara, Santa Barbara, California, United States of America
| | - Terry Watnick
- Division of Nephrology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Michael Köttgen
- Renal Division, Department of Medicine, Medical Center – University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
- * E-mail: (AH); (MK)
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97
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King MS, Thompson K, Hopton S, He L, Kunji ERS, Taylor RW, Ortiz-Gonzalez XR. Expanding the phenotype of de novo SLC25A4-linked mitochondrial disease to include mild myopathy. Neurol Genet 2018; 4:e256. [PMID: 30046662 PMCID: PMC6055355 DOI: 10.1212/nxg.0000000000000256] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 05/15/2018] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To determine the disease relevance of a novel de novo dominant variant in the SLC25A4 gene, encoding the muscle mitochondrial adenosine diphosphate (ADP)/adenosine triphosphate (ATP) carrier, identified in a child presenting with a previously unreported phenotype of mild childhood-onset myopathy. METHODS Immunohistochemical and western blot analysis of the patient's muscle tissue were used to assay for the evidence of mitochondrial myopathy and for complex I-V protein levels. To determine the effect of a putative pathogenic p.Lys33Gln variant on ADP/ATP transport, the mutant protein was expressed in Lactococcus lactis and its transport activity was assessed with fused membrane vesicles. RESULTS Our data demonstrate that the heterozygous c.97A>T (p.Lys33Gln) SLC25A4 variant is associated with classic muscle biopsy findings of mitochondrial myopathy (cytochrome c oxidase [COX]-deficient and ragged blue fibers), significantly impaired ADP/ATP transport in Lactococcus lactis and decreased complex I, III, and IV protein levels in patient's skeletal muscle. Nonetheless, the expression levels of the total ADP/ATP carrier (AAC) content in the muscle biopsy was largely unaffected. CONCLUSIONS This report further expands the clinical phenotype of de novo dominant SLC25A4 mutations to a childhood-onset, mild skeletal myopathy, without evidence of previously reported clinical features associated with SLC25A4-associated disease, such as cardiomyopathy, encephalopathy or ophthalmoplegia. The most likely reason for the milder disease phenotype is that the overall AAC expression levels were not affected, meaning that expression of the wild-type allele and other isoforms may in part have compensated for the impaired mutant variant.
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Affiliation(s)
- Martin S King
- Medical Research Council Mitochondrial Biology Unit (M.S.K., E.R.S.K.), University of Cambridge, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, UK; Wellcome Centre for Mitochondrial Research (K.T., S.H., L.H., R.W.D.), Institute of Neuroscience, Newcastle University, UK; and Department of Neurology (X.R.O.), Perelman School of Medicine, Division of Neurology and Center for Mitochondrial and Epigenomic Medicine, The Children's Hospital of Philadelphia, University of Pennsylvania
| | - Kyle Thompson
- Medical Research Council Mitochondrial Biology Unit (M.S.K., E.R.S.K.), University of Cambridge, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, UK; Wellcome Centre for Mitochondrial Research (K.T., S.H., L.H., R.W.D.), Institute of Neuroscience, Newcastle University, UK; and Department of Neurology (X.R.O.), Perelman School of Medicine, Division of Neurology and Center for Mitochondrial and Epigenomic Medicine, The Children's Hospital of Philadelphia, University of Pennsylvania
| | - Sila Hopton
- Medical Research Council Mitochondrial Biology Unit (M.S.K., E.R.S.K.), University of Cambridge, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, UK; Wellcome Centre for Mitochondrial Research (K.T., S.H., L.H., R.W.D.), Institute of Neuroscience, Newcastle University, UK; and Department of Neurology (X.R.O.), Perelman School of Medicine, Division of Neurology and Center for Mitochondrial and Epigenomic Medicine, The Children's Hospital of Philadelphia, University of Pennsylvania
| | - Langping He
- Medical Research Council Mitochondrial Biology Unit (M.S.K., E.R.S.K.), University of Cambridge, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, UK; Wellcome Centre for Mitochondrial Research (K.T., S.H., L.H., R.W.D.), Institute of Neuroscience, Newcastle University, UK; and Department of Neurology (X.R.O.), Perelman School of Medicine, Division of Neurology and Center for Mitochondrial and Epigenomic Medicine, The Children's Hospital of Philadelphia, University of Pennsylvania
| | - Edmund R S Kunji
- Medical Research Council Mitochondrial Biology Unit (M.S.K., E.R.S.K.), University of Cambridge, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, UK; Wellcome Centre for Mitochondrial Research (K.T., S.H., L.H., R.W.D.), Institute of Neuroscience, Newcastle University, UK; and Department of Neurology (X.R.O.), Perelman School of Medicine, Division of Neurology and Center for Mitochondrial and Epigenomic Medicine, The Children's Hospital of Philadelphia, University of Pennsylvania
| | - Robert W Taylor
- Medical Research Council Mitochondrial Biology Unit (M.S.K., E.R.S.K.), University of Cambridge, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, UK; Wellcome Centre for Mitochondrial Research (K.T., S.H., L.H., R.W.D.), Institute of Neuroscience, Newcastle University, UK; and Department of Neurology (X.R.O.), Perelman School of Medicine, Division of Neurology and Center for Mitochondrial and Epigenomic Medicine, The Children's Hospital of Philadelphia, University of Pennsylvania
| | - Xilma R Ortiz-Gonzalez
- Medical Research Council Mitochondrial Biology Unit (M.S.K., E.R.S.K.), University of Cambridge, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, UK; Wellcome Centre for Mitochondrial Research (K.T., S.H., L.H., R.W.D.), Institute of Neuroscience, Newcastle University, UK; and Department of Neurology (X.R.O.), Perelman School of Medicine, Division of Neurology and Center for Mitochondrial and Epigenomic Medicine, The Children's Hospital of Philadelphia, University of Pennsylvania
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98
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Specific cardiolipin-SecY interactions are required for proton-motive force stimulation of protein secretion. Proc Natl Acad Sci U S A 2018; 115:7967-7972. [PMID: 30012626 DOI: 10.1073/pnas.1721536115] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The transport of proteins across or into membranes is a vital biological process, achieved in every cell by the conserved Sec machinery. In bacteria, SecYEG combines with the SecA motor protein for secretion of preproteins across the plasma membrane, powered by ATP hydrolysis and the transmembrane proton-motive force (PMF). The activities of SecYEG and SecA are modulated by membrane lipids, particularly cardiolipin (CL), a specialized phospholipid known to associate with a range of energy-transducing machines. Here, we identify two specific CL binding sites on the Thermotoga maritima SecA-SecYEG complex, through application of coarse-grained molecular dynamics simulations. We validate the computational data and demonstrate the conserved nature of the binding sites using in vitro mutagenesis, native mass spectrometry, biochemical analysis, and fluorescence spectroscopy of Escherichia coli SecYEG. The results show that the two sites account for the preponderance of functional CL binding to SecYEG, and mediate its roles in ATPase and protein transport activity. In addition, we demonstrate an important role for CL in the conferral of PMF stimulation of protein transport. The apparent transient nature of the CL interaction might facilitate proton exchange with the Sec machinery, and thereby stimulate protein transport, by a hitherto unexplored mechanism. This study demonstrates the power of coupling the high predictive ability of coarse-grained simulation with experimental analyses, toward investigation of both the nature and functional implications of protein-lipid interactions.
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99
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Autzen HE, Koldsø H, Stansfeld PJ, Gourdon P, Sansom MSP, Nissen P. Interactions of a Bacterial Cu(I)-ATPase with a Complex Lipid Environment. Biochemistry 2018; 57:4063-4073. [DOI: 10.1021/acs.biochem.8b00326] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Henriette E. Autzen
- Centre for Membrane Pumps in Cells and Disease (PUMPkin), Danish National Research Foundation, 8000 Aarhus, Denmark
- Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds vej 10C, 8000 Aarhus C, Denmark
| | - Heidi Koldsø
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
| | - Phillip J. Stansfeld
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
| | - Pontus Gourdon
- Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen N, Denmark
| | - Mark S. P. Sansom
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
| | - Poul Nissen
- Centre for Membrane Pumps in Cells and Disease (PUMPkin), Danish National Research Foundation, 8000 Aarhus, Denmark
- Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds vej 10C, 8000 Aarhus C, Denmark
- Danish Research Institute of Translational Neuroscience (DANDRITE), Nordic-EMBL Partnership for Molecular Medicine, Aarhus University, 8000 Aarhus C, Denmark
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100
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Bai X, Moraes TF, Reithmeier RAF. Structural biology of solute carrier (SLC) membrane transport proteins. Mol Membr Biol 2018; 34:1-32. [PMID: 29651895 DOI: 10.1080/09687688.2018.1448123] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The human solute carriers (SLCs) comprise over 400 different transporters, organized into 65 families ( http://slc.bioparadigms.org/ ) based on their sequence homology and transport function. SLCs are responsible for transporting extraordinarily diverse solutes across biological membranes, including inorganic ions, amino acids, lipids, sugars, neurotransmitters and drugs. Most of these membrane proteins function as coupled symporters (co-transporters) utilizing downhill ion (H+ or Na+) gradients as the driving force for the transport of substrate against its concentration gradient into cells. Other members work as antiporters (exchangers) that typically contain a single substrate-binding site with an alternating access mode of transport, while a few members exhibit channel-like properties. Dysfunction of SLCs is correlated with numerous human diseases and therefore they are potential therapeutic drug targets. In this review, we identified all of the SLC crystal structures that have been determined, most of which are from prokaryotic species. We further sorted all the SLC structures into four main groups with different protein folds and further discuss the well-characterized MFS (major facilitator superfamily) and LeuT (leucine transporter) folds. This review provides a systematic analysis of the structure, molecular basis of substrate recognition and mechanism of action in different SLC family members.
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Affiliation(s)
- Xiaoyun Bai
- a Department of Biochemistry , University of Toronto , Toronto , Canada
| | - Trevor F Moraes
- a Department of Biochemistry , University of Toronto , Toronto , Canada
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