1
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Chi X, Chen Y, Li Y, Dai L, Zhang Y, Shen Y, Chen Y, Shi T, Yang H, Wang Z, Yan R. Cryo-EM structures of the human NaS1 and NaDC1 transporters revealed the elevator transport and allosteric regulation mechanism. SCIENCE ADVANCES 2024; 10:eadl3685. [PMID: 38552027 PMCID: PMC10980263 DOI: 10.1126/sciadv.adl3685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2023] [Accepted: 02/26/2024] [Indexed: 04/01/2024]
Abstract
The solute carrier 13 (SLC13) family comprises electrogenic sodium ion-coupled anion cotransporters, segregating into sodium ion-sulfate cotransporters (NaSs) and sodium ion-di- and-tricarboxylate cotransporters (NaDCs). NaS1 and NaDC1 regulate sulfate homeostasis and oxidative metabolism, respectively. NaS1 deficiency affects murine growth and fertility, while NaDC1 affects urinary citrate and calcium nephrolithiasis. Despite their importance, the mechanisms of substrate recognition and transport remain insufficiently characterized. In this study, we determined the cryo-electron microscopy structures of human NaS1, capturing inward-facing and combined inward-facing/outward-facing conformations within a dimer both in apo and sulfate-bound states. In addition, we elucidated NaDC1's outward-facing conformation, encompassing apo, citrate-bound, and N-(p-amylcinnamoyl) anthranilic acid (ACA) inhibitor-bound states. Structural scrutiny illuminates a detailed elevator mechanism driving conformational changes. Notably, the ACA inhibitor unexpectedly binds primarily anchored by transmembrane 2 (TM2), Loop 10, TM11, and TM6a proximate to the cytosolic membrane. Our findings provide crucial insights into SLC13 transport mechanisms, paving the way for future drug design.
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Affiliation(s)
- Ximin Chi
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Science, Xiamen University, Xiamen 361102, Fujian Province, China
- Center for Infectious Disease Research, Westlake Laboratory of Life Sciences and Biomedicine, Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou 310024, Zhejiang Province, China
| | - Yiming Chen
- Department of Medical Neuroscience, Key University Laboratory of Metabolism and Health of Guangdong, School of Medicine, Southern University of Science and Technology, Shenzhen 518055, Guangdong Province, China
| | - Yaning Li
- Center for Infectious Disease Research, Westlake Laboratory of Life Sciences and Biomedicine, Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou 310024, Zhejiang Province, China
- Department of Biochemistry, Key University Laboratory of Metabolism and Health of Guangdong, School of Medicine, Institute for Biological Electron Microscopy, Southern University of Science and Technology, Shenzhen 518055, Guangdong Province, China
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Lu Dai
- Department of Biochemistry, Key University Laboratory of Metabolism and Health of Guangdong, School of Medicine, Institute for Biological Electron Microscopy, Southern University of Science and Technology, Shenzhen 518055, Guangdong Province, China
| | - Yuanyuan Zhang
- Center for Infectious Disease Research, Westlake Laboratory of Life Sciences and Biomedicine, Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou 310024, Zhejiang Province, China
| | - Yaping Shen
- Center for Infectious Disease Research, Westlake Laboratory of Life Sciences and Biomedicine, Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou 310024, Zhejiang Province, China
| | - Yun Chen
- Center for Infectious Disease Research, Westlake Laboratory of Life Sciences and Biomedicine, Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou 310024, Zhejiang Province, China
- Novoprotein Scientific Inc., Suzhou 215000, China
| | - Tianhao Shi
- Department of Biochemistry, Key University Laboratory of Metabolism and Health of Guangdong, School of Medicine, Institute for Biological Electron Microscopy, Southern University of Science and Technology, Shenzhen 518055, Guangdong Province, China
| | - Haonan Yang
- Department of Biochemistry, Key University Laboratory of Metabolism and Health of Guangdong, School of Medicine, Institute for Biological Electron Microscopy, Southern University of Science and Technology, Shenzhen 518055, Guangdong Province, China
| | - Zilong Wang
- Department of Medical Neuroscience, Key University Laboratory of Metabolism and Health of Guangdong, School of Medicine, Southern University of Science and Technology, Shenzhen 518055, Guangdong Province, China
| | - Renhong Yan
- Department of Biochemistry, Key University Laboratory of Metabolism and Health of Guangdong, School of Medicine, Institute for Biological Electron Microscopy, Southern University of Science and Technology, Shenzhen 518055, Guangdong Province, China
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2
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Currie MJ, Davies JS, Scalise M, Gulati A, Wright JD, Newton-Vesty MC, Abeysekera GS, Subramanian R, Wahlgren WY, Friemann R, Allison JR, Mace PD, Griffin MDW, Demeler B, Wakatsuki S, Drew D, Indiveri C, Dobson RCJ, North RA. Structural and biophysical analysis of a Haemophilus influenzae tripartite ATP-independent periplasmic (TRAP) transporter. eLife 2024; 12:RP92307. [PMID: 38349818 PMCID: PMC10942642 DOI: 10.7554/elife.92307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2024] Open
Abstract
Tripartite ATP-independent periplasmic (TRAP) transporters are secondary-active transporters that receive their substrates via a soluble-binding protein to move bioorganic acids across bacterial or archaeal cell membranes. Recent cryo-electron microscopy (cryo-EM) structures of TRAP transporters provide a broad framework to understand how they work, but the mechanistic details of transport are not yet defined. Here we report the cryo-EM structure of the Haemophilus influenzae N-acetylneuraminate TRAP transporter (HiSiaQM) at 2.99 Å resolution (extending to 2.2 Å at the core), revealing new features. The improved resolution (the previous HiSiaQM structure is 4.7 Å resolution) permits accurate assignment of two Na+ sites and the architecture of the substrate-binding site, consistent with mutagenic and functional data. Moreover, rather than a monomer, the HiSiaQM structure is a homodimer. We observe lipids at the dimer interface, as well as a lipid trapped within the fusion that links the SiaQ and SiaM subunits. We show that the affinity (KD) for the complex between the soluble HiSiaP protein and HiSiaQM is in the micromolar range and that a related SiaP can bind HiSiaQM. This work provides key data that enhances our understanding of the 'elevator-with-an-operator' mechanism of TRAP transporters.
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Affiliation(s)
- Michael J Currie
- Biomolecular Interaction Centre, Maurice Wilkins Centre for Biodiscovery, MacDiarmid Institute for Advanced Materials and Nanotechnology, and School of Biological Sciences, University of CanterburyChristchurchNew Zealand
| | - James S Davies
- Biomolecular Interaction Centre, Maurice Wilkins Centre for Biodiscovery, MacDiarmid Institute for Advanced Materials and Nanotechnology, and School of Biological Sciences, University of CanterburyChristchurchNew Zealand
- Department of Biochemistry and Biophysics, Stockholm UniversityStockholmSweden
| | - Mariafrancesca Scalise
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of CalabriaArcavacata di RendeItaly
| | - Ashutosh Gulati
- Department of Biochemistry and Biophysics, Stockholm UniversityStockholmSweden
| | - Joshua D Wright
- Biomolecular Interaction Centre, Maurice Wilkins Centre for Biodiscovery, MacDiarmid Institute for Advanced Materials and Nanotechnology, and School of Biological Sciences, University of CanterburyChristchurchNew Zealand
| | - Michael C Newton-Vesty
- Biomolecular Interaction Centre, Maurice Wilkins Centre for Biodiscovery, MacDiarmid Institute for Advanced Materials and Nanotechnology, and School of Biological Sciences, University of CanterburyChristchurchNew Zealand
| | - Gayan S Abeysekera
- Biomolecular Interaction Centre, Maurice Wilkins Centre for Biodiscovery, MacDiarmid Institute for Advanced Materials and Nanotechnology, and School of Biological Sciences, University of CanterburyChristchurchNew Zealand
| | - Ramaswamy Subramanian
- Biological Sciences and Biomedical Engineering, Bindley Bioscience Center, Purdue University West LafayetteWest LafayetteUnited States
| | - Weixiao Y Wahlgren
- Department of Chemistry and Molecular Biology, Biochemistry and Structural Biology, University of GothenburgGothenburgSweden
| | - Rosmarie Friemann
- Centre for Antibiotic Resistance Research (CARe) at University of GothenburgGothenburgSweden
| | - Jane R Allison
- Biomolecular Interaction Centre, Digital Life Institute, Maurice Wilkins Centre for Molecular Biodiscovery, and School of Biological Sciences, University of AucklandAucklandNew Zealand
| | - Peter D Mace
- Biochemistry Department, School of Biomedical Sciences, University of OtagoDunedinNew Zealand
| | - Michael DW Griffin
- ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Bio Molecular Science and Biotechnology Institute, Department of Biochemistry and Pharmacology, University of MelbourneMelbourneAustralia
| | - Borries Demeler
- Department of Chemistry and Biochemistry, University of MontanaMissoulaUnited States
- Department of Chemistry and Biochemistry, University of LethbridgeLethbridgeCanada
| | - Soichi Wakatsuki
- Biological Sciences Division, SLAC National Accelerator LaboratoryMenlo ParkUnited States
- Department of Structural Biology, Stanford University School of MedicineStanfordUnited States
| | - David Drew
- Department of Biochemistry and Biophysics, Stockholm UniversityStockholmSweden
| | - Cesare Indiveri
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of CalabriaArcavacata di RendeItaly
- CNR Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM)BariItaly
| | - Renwick CJ Dobson
- Biomolecular Interaction Centre, Maurice Wilkins Centre for Biodiscovery, MacDiarmid Institute for Advanced Materials and Nanotechnology, and School of Biological Sciences, University of CanterburyChristchurchNew Zealand
- ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Bio Molecular Science and Biotechnology Institute, Department of Biochemistry and Pharmacology, University of MelbourneMelbourneAustralia
| | - Rachel A North
- Department of Biochemistry and Biophysics, Stockholm UniversityStockholmSweden
- School of Medical Sciences, Faculty of Medicine and Health, University of SydneySydneyAustralia
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3
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Alsemari A, Guzmán-Vega FJ, Meyer BF, Arold ST. Novel Homozygous Variants of SLC13A5 Expand the Functional Heterogeneity of a Homogeneous Syndrome of Early Infantile Epileptic Encephalopathy. Pediatr Neurol 2024; 151:68-72. [PMID: 38113697 DOI: 10.1016/j.pediatrneurol.2023.10.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 09/19/2023] [Accepted: 10/13/2023] [Indexed: 12/21/2023]
Abstract
BACKGROUND Early infantile epileptic encephalopathy 25 (EIEE25) is a distinct type of neonatal epileptic encephalopathy caused by autosomal recessive mutations in the SLC13A5 gene. SLC13A5 encodes a transmembrane sodium/citrate cotransporter required for regulating citrate entry into cells. METHODS Four families with recessively inherited epileptic encephalopathy were sequenced by clinically accredited laboratories using commercially available epilepsy gene panels. Patients were examined by a neurologist and were clinically diagnosed with infantile epileptic encephalopathy. RESULTS We present four families with global developmental delay, intellectual disability, and defective tooth development with four novel homozygous mutations in SLC13A5. The neurological examination showed spastic quadriplegia with increased deep tendon reflexes. Brain magnetic resonance imaging showed nonspecific signal abnormality of the bilateral hemispheric white matter. Despite similar clinical features, the conditions were based on different molecular mechanisms acting on SLC13A5 (abnormal splicing, large-scale deletions, and tandem-residue insertion). CONCLUSIONS Our results extend the landscape of autosomal recessive inherited homozygous mutations in SLC13A5 that cause a distinctive syndrome of severe neonatal epileptic encephalopathy. Our observations confirm the homogeneity of epileptic encephalopathy and dental abnormalities as a distinct clinical marker for EIEE25 despite the heterogeneous functional and mutational background.
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Affiliation(s)
- Abdulaziz Alsemari
- Department of Neurosciences, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia; Department of Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia.
| | - Francisco J Guzmán-Vega
- Saudi Human Genome Project, King Abdulaziz City for Science and Technology, Riyadh, Saudi Arabia
| | - Brian F Meyer
- Department of Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia; Division of Biological and Environmental Sciences and Engineering (BESE), King Abdullah University of Science and Technology (KAUST), Computational Bioscience Research Centre (CBRC), Thuwal, Saudi Arabia
| | - Stefan T Arold
- Saudi Human Genome Project, King Abdulaziz City for Science and Technology, Riyadh, Saudi Arabia
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4
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Paul NP, Viswanathan T, Chen J, Yoshinaga M, Rosen BP. The ArsQ permease and transport of the antibiotic arsinothricin. Mol Microbiol 2023; 119:505-514. [PMID: 36785875 PMCID: PMC10101903 DOI: 10.1111/mmi.15045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Revised: 01/31/2023] [Accepted: 02/06/2023] [Indexed: 02/15/2023]
Abstract
The pentavalent organoarsenical arsinothricin (AST) is a natural product synthesized by the rhizosphere bacterium Burkholderia gladioli GSRB05. AST is a broad-spectrum antibiotic effective against human pathogens such as carbapenem-resistant Enterobacter cloacae. It is a non-proteogenic amino acid and glutamate mimetic that inhibits bacterial glutamine synthetase. The AST biosynthetic pathway is composed of a three-gene cluster, arsQML. ArsL catalyzes synthesis of reduced trivalent hydroxyarsinothricin (R-AST-OH), which is methylated by ArsM to the reduced trivalent form of AST (R-AST). In the culture medium of B. gladioli, both trivalent species appear as the corresponding pentavalent arsenicals, likely due to oxidation in air. ArsQ is an efflux permease that is proposed to transport AST or related species out of the cells, but the chemical nature of the actual transport substrate is unclear. In this study, B. gladioli arsQ was expressed in Escherichia coli and shown to confer resistance to AST and its derivatives. Cells of E. coli accumulate R-AST, and exponentially growing cells expressing arsQ take up less R-AST. The cells exhibit little transport of their pentavalent forms. Transport was independent of cellular energy and appears to be equilibrative. A homology model of ArsQ suggests that Ser320 is in the substrate binding site. A S320A mutant exhibits reduced R-AST-OH transport, suggesting that it plays a role in ArsQ function. The ArsQ permease is proposed to be an energy-independent uniporter responsible for downhill transport of the trivalent form of AST out of cells, which is oxidized extracellularly to the active form of the antibiotic.
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Affiliation(s)
- Ngozi P. Paul
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, Florida 33199, U.S.A
| | - Thiruselvam Viswanathan
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, Florida 33199, U.S.A
| | - Jian Chen
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, Florida 33199, U.S.A
| | - Masafumi Yoshinaga
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, Florida 33199, U.S.A
| | - Barry P. Rosen
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, Florida 33199, U.S.A
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5
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Davies JS, Currie MJ, North RA, Scalise M, Wright JD, Copping JM, Remus DM, Gulati A, Morado DR, Jamieson SA, Newton-Vesty MC, Abeysekera GS, Ramaswamy S, Friemann R, Wakatsuki S, Allison JR, Indiveri C, Drew D, Mace PD, Dobson RCJ. Structure and mechanism of a tripartite ATP-independent periplasmic TRAP transporter. Nat Commun 2023; 14:1120. [PMID: 36849793 PMCID: PMC9971032 DOI: 10.1038/s41467-023-36590-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Accepted: 02/07/2023] [Indexed: 03/01/2023] Open
Abstract
In bacteria and archaea, tripartite ATP-independent periplasmic (TRAP) transporters uptake essential nutrients. TRAP transporters receive their substrates via a secreted soluble substrate-binding protein. How a sodium ion-driven secondary active transporter is strictly coupled to a substrate-binding protein is poorly understood. Here we report the cryo-EM structure of the sialic acid TRAP transporter SiaQM from Photobacterium profundum at 2.97 Å resolution. SiaM comprises a "transport" domain and a "scaffold" domain, with the transport domain consisting of helical hairpins as seen in the sodium ion-coupled elevator transporter VcINDY. The SiaQ protein forms intimate contacts with SiaM to extend the size of the scaffold domain, suggesting that TRAP transporters may operate as monomers, rather than the typically observed oligomers for elevator-type transporters. We identify the Na+ and sialic acid binding sites in SiaM and demonstrate a strict dependence on the substrate-binding protein SiaP for uptake. We report the SiaP crystal structure that, together with docking studies, suggest the molecular basis for how sialic acid is delivered to the SiaQM transporter complex. We thus propose a model for substrate transport by TRAP proteins, which we describe herein as an 'elevator-with-an-operator' mechanism.
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Affiliation(s)
- James S Davies
- Biomolecular Interaction Centre, Maurice Wilkins Centre for Biodiscovery, MacDiarmid Institute for Advanced Materials and Nanotechnology and School of Biological Sciences, University of Canterbury, PO Box 4800, Christchurch, 8140, New Zealand.,Department of Biochemistry and Biophysics, Stockholm University, 10691, Stockholm, Sweden
| | - Michael J Currie
- Biomolecular Interaction Centre, Maurice Wilkins Centre for Biodiscovery, MacDiarmid Institute for Advanced Materials and Nanotechnology and School of Biological Sciences, University of Canterbury, PO Box 4800, Christchurch, 8140, New Zealand
| | - Rachel A North
- Biomolecular Interaction Centre, Maurice Wilkins Centre for Biodiscovery, MacDiarmid Institute for Advanced Materials and Nanotechnology and School of Biological Sciences, University of Canterbury, PO Box 4800, Christchurch, 8140, New Zealand. .,Department of Biochemistry and Biophysics, Stockholm University, 10691, Stockholm, Sweden.
| | - Mariafrancesca Scalise
- 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
| | - Joshua D Wright
- Biomolecular Interaction Centre, Maurice Wilkins Centre for Biodiscovery, MacDiarmid Institute for Advanced Materials and Nanotechnology and School of Biological Sciences, University of Canterbury, PO Box 4800, Christchurch, 8140, New Zealand
| | - Jack M Copping
- Biomolecular Interaction Centre, Digital Life Institute, Maurice Wilkins Centre for Molecular Biodiscovery, and School of Biological Sciences, University of Auckland, Auckland, 1010, New Zealand
| | - Daniela M Remus
- Biomolecular Interaction Centre, Maurice Wilkins Centre for Biodiscovery, MacDiarmid Institute for Advanced Materials and Nanotechnology and School of Biological Sciences, University of Canterbury, PO Box 4800, Christchurch, 8140, New Zealand
| | - Ashutosh Gulati
- Department of Biochemistry and Biophysics, Stockholm University, 10691, Stockholm, Sweden
| | - Dustin R Morado
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, 17165, Solna, Sweden
| | - Sam A Jamieson
- Biochemistry Department, School of Biomedical Sciences, University of Otago, Dunedin, 9054, New Zealand
| | - Michael C Newton-Vesty
- Biomolecular Interaction Centre, Maurice Wilkins Centre for Biodiscovery, MacDiarmid Institute for Advanced Materials and Nanotechnology and School of Biological Sciences, University of Canterbury, PO Box 4800, Christchurch, 8140, New Zealand
| | - Gayan S Abeysekera
- Biomolecular Interaction Centre, Maurice Wilkins Centre for Biodiscovery, MacDiarmid Institute for Advanced Materials and Nanotechnology and School of Biological Sciences, University of Canterbury, PO Box 4800, Christchurch, 8140, New Zealand
| | - Subramanian Ramaswamy
- Biological Sciences and Biomedical Engineering, Bindley Bioscience Center, Purdue University, 1203 W State St, West Lafayette, IN 47906, USA
| | - Rosmarie Friemann
- Centre for Antibiotic Resistance Research (CARe) at University of Gothenburg, Box 440, S-40530, Gothenburg, Sweden
| | - Soichi Wakatsuki
- Biological Sciences Division, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA.,Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Jane R Allison
- Biomolecular Interaction Centre, Digital Life Institute, Maurice Wilkins Centre for Molecular Biodiscovery, and School of Biological Sciences, University of Auckland, Auckland, 1010, New Zealand
| | - 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.,CNR Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), Via Amendola 122/O, 70126, Bari, Italy
| | - David Drew
- Department of Biochemistry and Biophysics, Stockholm University, 10691, Stockholm, Sweden
| | - Peter D Mace
- Biochemistry Department, School of Biomedical Sciences, University of Otago, Dunedin, 9054, New Zealand
| | - Renwick C J Dobson
- Biomolecular Interaction Centre, Maurice Wilkins Centre for Biodiscovery, MacDiarmid Institute for Advanced Materials and Nanotechnology and School of Biological Sciences, University of Canterbury, PO Box 4800, Christchurch, 8140, New Zealand. .,Bio21 Molecular Science and Biotechnology Institute, Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, 3010, Australia.
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6
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Ranganathan S, Sethi D, Kasivisweswaran S, Ramya L, Priyadarshini R, Yennamalli RM. Structural and functional mapping of ars gene cluster in Deinococcus indicus DR1. Comput Struct Biotechnol J 2022; 21:519-534. [PMID: 36618989 PMCID: PMC9807832 DOI: 10.1016/j.csbj.2022.12.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 12/08/2022] [Accepted: 12/08/2022] [Indexed: 12/14/2022] Open
Abstract
Deinococcus indicus DR1 is a novel Gram-negative bacterium, isolated from the Dadri wetlands in Uttar Pradesh, India. In addition to being radiation-resistant, the rod-shaped, red-pigmented organism shows extraordinary resistance to arsenic. The proteins of the corresponding ars gene cluster involved in arsenic extrusion in D. indicus DR1 have not yet been characterized. Additionally, how these proteins regulate each other providing arsenic resistance is still unclear. Here, we present a computational model of the operonic structure and the corresponding characterization of the six proteins of the ars gene cluster in D. indicus DR1. Additionally, we show the expression of the genes in the presence of arsenic using qRT-PCR. The ars gene cluster consists of two transcriptional regulators (ArsR1, ArsR2), two arsenate reductases (ArsC2, ArsC3), one metallophosphatase family protein (MPase), and a transmembrane arsenite efflux pump (ArsB). The transcriptional regulators are trans-acting repressors, and the reductases reduce arsenate (As5+) ions to arsenite (As3+) ions for favourable extrusion. The proteins modelled using RoseTTAFold, and their conformationally stable coordinates obtained after MD simulation indicate their various functional roles with respect to arsenic. Excluding ArsB, all the proteins belong to the α + β class of proteins. ArsB, being a membrane protein, is fully α-helical, with 12 transmembrane helices. The results show the degree of similarity or divergence of the mechanism utilized by these proteins of ars gene cluster in D. indicus DR1 to confer high levels of arsenic tolerance. This structural characterization study of the ars genes will enable new and deeper insights of arsenic tolerance.
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Affiliation(s)
- Shrivaishnavi Ranganathan
- Department of Biotechnology, School of Chemical and Biotechnology, SASTRA Deemed to be University, Thanjavur, Tamil Nadu 613401, India
| | - Deepa Sethi
- Department of Life Sciences, School of Natural Sciences, Shiv Nadar University, Gautam Buddha Nagar, Uttar Pradesh, India
| | - Sandhya Kasivisweswaran
- Department of Life Sciences, School of Natural Sciences, Shiv Nadar University, Gautam Buddha Nagar, Uttar Pradesh, India
| | - L. Ramya
- Computational and Molecular Biophysics Laboratory, School of Chemical and Biotechnology, SASTRA Deemed to be University, Thanjavur, Tamil Nadu 613401, India
| | - Richa Priyadarshini
- Department of Life Sciences, School of Natural Sciences, Shiv Nadar University, Gautam Buddha Nagar, Uttar Pradesh, India,Corresponding authors.
| | - Ragothaman M. Yennamalli
- Department of Bioinformatics, School of Chemical and Biotechnology, SASTRA Deemed to be University, Thanjavur, Tamil Nadu 613401, India,Corresponding authors.
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7
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Prokaryotic Na+/H+ Exchangers—Transport Mechanism and Essential Residues. Int J Mol Sci 2022; 23:ijms23169156. [PMID: 36012428 PMCID: PMC9408914 DOI: 10.3390/ijms23169156] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 08/09/2022] [Accepted: 08/13/2022] [Indexed: 11/16/2022] Open
Abstract
Na+/H+ exchangers are essential for Na+ and pH homeostasis in all organisms. Human Na+/H+ exchangers are of high medical interest, and insights into their structure and function are aided by the investigation of prokaryotic homologues. Most prokaryotic Na+/H+ exchangers belong to either the Cation/Proton Antiporter (CPA) superfamily, the Ion Transport (IT) superfamily, or the Na+-translocating Mrp transporter superfamily. Several structures have been solved so far for CPA and Mrp members, but none for the IT members. NhaA from E. coli has served as the prototype of Na+/H+ exchangers due to the high amount of structural and functional data available. Recent structures from other CPA exchangers, together with diverse functional information, have allowed elucidation of some common working principles shared by Na+/H+ exchangers from different families, such as the type of residues involved in the substrate binding and even a simple mechanism sufficient to explain the pH regulation in the CPA and IT superfamilies. Here, we review several aspects of prokaryotic Na+/H+ exchanger structure and function, discussing the similarities and differences between different transporters, with a focus on the CPA and IT exchangers. We also discuss the proposed transport mechanisms for Na+/H+ exchangers that explain their highly pH-regulated activity profile.
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8
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Peter MF, Ruland JA, Depping P, Schneberger N, Severi E, Moecking J, Gatterdam K, Tindall S, Durand A, Heinz V, Siebrasse JP, Koenig PA, Geyer M, Ziegler C, Kubitscheck U, Thomas GH, Hagelueken G. Structural and mechanistic analysis of a tripartite ATP-independent periplasmic TRAP transporter. Nat Commun 2022; 13:4471. [PMID: 35927235 PMCID: PMC9352664 DOI: 10.1038/s41467-022-31907-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Accepted: 07/08/2022] [Indexed: 11/27/2022] Open
Abstract
Tripartite ATP-independent periplasmic (TRAP) transporters are found widely in bacteria and archaea and consist of three structural domains, a soluble substrate-binding protein (P-domain), and two transmembrane domains (Q- and M-domains). HiSiaPQM and its homologs are TRAP transporters for sialic acid and are essential for host colonization by pathogenic bacteria. Here, we reconstitute HiSiaQM into lipid nanodiscs and use cryo-EM to reveal the structure of a TRAP transporter. It is composed of 16 transmembrane helices that are unexpectedly structurally related to multimeric elevator-type transporters. The idiosyncratic Q-domain of TRAP transporters enables the formation of a monomeric elevator architecture. A model of the tripartite PQM complex is experimentally validated and reveals the coupling of the substrate-binding protein to the transporter domains. We use single-molecule total internal reflection fluorescence (TIRF) microscopy in solid-supported lipid bilayers and surface plasmon resonance to study the formation of the tripartite complex and to investigate the impact of interface mutants. Furthermore, we characterize high-affinity single variable domains on heavy chain (VHH) antibodies that bind to the periplasmic side of HiSiaQM and inhibit sialic acid uptake, providing insight into how TRAP transporter function might be inhibited in vivo.
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Affiliation(s)
- Martin F Peter
- Institute of Structural Biology, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
| | - Jan A Ruland
- Institute for Physical und Theoretical Chemistry, University of Bonn, Wegelerstr. 12, 53127, Bonn, Germany
| | - Peer Depping
- Institute of Structural Biology, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
- Aston Centre for Membrane Proteins and Lipids Research, Aston St., B4 7ET, Birmingham, UK
| | - Niels Schneberger
- Institute of Structural Biology, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
| | - Emmanuele Severi
- Department of Biology (Area 10), University of York, York, YO10 5YW, UK
- Biosciences Institute, Newcastle University, Newcastle, NE2 4HH, UK
| | - Jonas Moecking
- Institute of Structural Biology, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
| | - Karl Gatterdam
- Institute of Structural Biology, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
| | - Sarah Tindall
- Department of Biology (Area 10), University of York, York, YO10 5YW, UK
| | - Alexandre Durand
- Institut de Génétique et de Biologie Molecule et Cellulaire, 1 Rue Laurent Fries, 67404, Illkirch Cedex, France
| | - Veronika Heinz
- Institute of Biophysics and Biophysical Chemistry, University of Regensburg, Universitätsstr. 31, 93053, Regensburg, Germany
| | - Jan Peter Siebrasse
- Institute for Physical und Theoretical Chemistry, University of Bonn, Wegelerstr. 12, 53127, Bonn, Germany
| | - Paul-Albert Koenig
- Core Facility Nanobodies, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
| | - Matthias Geyer
- Institute of Structural Biology, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
| | - Christine Ziegler
- Institute of Biophysics and Biophysical Chemistry, University of Regensburg, Universitätsstr. 31, 93053, Regensburg, Germany
| | - Ulrich Kubitscheck
- Institute for Physical und Theoretical Chemistry, University of Bonn, Wegelerstr. 12, 53127, Bonn, Germany
| | - Gavin H Thomas
- Department of Biology (Area 10), University of York, York, YO10 5YW, UK
| | - Gregor Hagelueken
- Institute of Structural Biology, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany.
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9
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Lv P, Li Y, Wang R, Zhang Y, Wang W, Liu Y, Shang Y, Su D, Wang W, Yang C. The pH sensor and ion binding of NhaD Na
+
/H
+
antiporter from IT superfamily. Mol Microbiol 2022; 118:244-257. [DOI: 10.1111/mmi.14965] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Revised: 07/13/2022] [Accepted: 07/14/2022] [Indexed: 11/28/2022]
Affiliation(s)
- Peiwen Lv
- State Key Laboratory of Microbial Technology Institute of Microbial Technology, Shandong University Qingdao P. R. China
| | - Yaru Li
- State Key Laboratory of Microbial Technology Institute of Microbial Technology, Shandong University Qingdao P. R. China
| | - Ruimin Wang
- State Key Laboratory of Microbial Technology Institute of Microbial Technology, Shandong University Qingdao P. R. China
| | - Ye Zhang
- State Key Laboratory of Microbial Technology Institute of Microbial Technology, Shandong University Qingdao P. R. China
| | - Wenkai Wang
- State Key Laboratory of Microbial Technology Institute of Microbial Technology, Shandong University Qingdao P. R. China
| | - Yuanxiang Liu
- State Key Laboratory of Microbial Technology Institute of Microbial Technology, Shandong University Qingdao P. R. China
| | - Yan Shang
- State Key Laboratory of Microbial Technology Institute of Microbial Technology, Shandong University Qingdao P. R. China
| | - Dandan Su
- State Key Laboratory of Microbial Technology Institute of Microbial Technology, Shandong University Qingdao P. R. China
| | - Wei Wang
- State Key Laboratory of Microbial Technology Institute of Microbial Technology, Shandong University Qingdao P. R. China
| | - Chunyu Yang
- State Key Laboratory of Microbial Technology Institute of Microbial Technology, Shandong University Qingdao P. R. China
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10
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Sauer DB, Marden JJ, Sudar JC, Song J, Mulligan C, Wang DN. Structural basis of ion - substrate coupling in the Na +-dependent dicarboxylate transporter VcINDY. Nat Commun 2022; 13:2644. [PMID: 35551191 PMCID: PMC9098524 DOI: 10.1038/s41467-022-30406-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 04/28/2022] [Indexed: 11/21/2022] Open
Abstract
The Na+-dependent dicarboxylate transporter from Vibrio cholerae (VcINDY) is a prototype for the divalent anion sodium symporter (DASS) family. While the utilization of an electrochemical Na+ gradient to power substrate transport is well established for VcINDY, the structural basis of this coupling between sodium and substrate binding is not currently understood. Here, using a combination of cryo-EM structure determination, succinate binding and site-directed cysteine alkylation assays, we demonstrate that the VcINDY protein couples sodium- and substrate-binding via a previously unseen cooperative mechanism by conformational selection. In the absence of sodium, substrate binding is abolished, with the succinate binding regions exhibiting increased flexibility, including HPinb, TM10b and the substrate clamshell motifs. Upon sodium binding, these regions become structurally ordered and create a proper binding site for the substrate. Taken together, these results provide strong evidence that VcINDY's conformational selection mechanism is a result of the sodium-dependent formation of the substrate binding site.
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Affiliation(s)
- David B Sauer
- Department of Cell Biology, New York University School of Medicine, New York, NY, 10016, USA
- Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY, 10016, USA
- Centre for Medicines Discovery, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Jennifer J Marden
- Department of Cell Biology, New York University School of Medicine, New York, NY, 10016, USA
- Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY, 10016, USA
| | - Joseph C Sudar
- Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY, 10016, USA
| | - Jinmei Song
- Department of Cell Biology, New York University School of Medicine, New York, NY, 10016, USA
- Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY, 10016, USA
| | | | - Da-Neng Wang
- Department of Cell Biology, New York University School of Medicine, New York, NY, 10016, USA.
- Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY, 10016, USA.
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11
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Sauer DB, Wang B, Sudar JC, Song J, Marden J, Rice WJ, Wang DN. The ups and downs of elevator-type di-/tricarboxylate membrane transporters. FEBS J 2022; 289:1515-1523. [PMID: 34403567 PMCID: PMC9832446 DOI: 10.1111/febs.16158] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 07/27/2021] [Accepted: 08/16/2021] [Indexed: 01/13/2023]
Abstract
The divalent anion sodium symporter (DASS) family contains both sodium-driven anion cotransporters and anion/anion exchangers. The family belongs to a broader ion transporter superfamily (ITS), which comprises 24 families of transporters, including those of AbgT antibiotic efflux transporters. The human proteins in the DASS family play major physiological roles and are drug targets. We recently determined multiple structures of the human sodium-dependent citrate transporter (NaCT) and the succinate/dicarboxylate transporter from Lactobacillus acidophilus (LaINDY). Structures of both proteins show high degrees of structural similarity to the previously determined VcINDY fold. Conservation between these DASS protein structures and those from the AbgT family indicates that the VcINDY fold represents the overall protein structure for the entire ITS. The new structures of NaCT and LaINDY are captured in the inward- or outward-facing conformations, respectively. The domain arrangements in these structures agree with a rigid body elevator-type transport mechanism for substrate translocation across the membrane. Two separate NaCT structures in complex with a substrate or an inhibitor allowed us to explain the inhibition mechanism and propose a detailed classification scheme for grouping disease-causing mutations in the human protein. Structural understanding of multiple kinetic states of DASS proteins is a first step toward the detailed characterization of their entire transport cycle.
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Affiliation(s)
- David B. Sauer
- Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY 10016, USA
| | - Bing Wang
- Cryo-Electron Microscopy Core, New York University School of Medicine, New York, NY 10016, USA
| | - Joseph C. Sudar
- Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY 10016, USA
| | - Jinmei Song
- Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY 10016, USA
| | - Jennifer Marden
- Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY 10016, USA
| | - William J. Rice
- Cryo-Electron Microscopy Core, New York University School of Medicine, New York, NY 10016, USA
| | - Da-Neng Wang
- Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY 10016, USA
- Department of Cell Biology, New York University School of Medicine, New York, NY 10016, USA
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12
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Yan H, Xu W, Zhang T, Feng L, Liu R, Wang L, Wu L, Zhang H, Zhang X, Li T, Peng Z, Jin C, Yu Y, Ping J, Ma M, He Z. Characterization of a novel arsenite long-distance transporter from arsenic hyperaccumulator fern Pteris vittata. THE NEW PHYTOLOGIST 2022; 233:2488-2502. [PMID: 35015902 DOI: 10.1111/nph.17962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Accepted: 12/22/2021] [Indexed: 06/14/2023]
Abstract
Pteris vittata is an arsenic (As) hyperaccumulator that can accumulate several thousand mg As kg-1 DW in aboveground biomass. A key factor for its hyperaccumulation ability is its highly efficient As long-distance translocation system. However, the underlying molecular mechanisms remain unknown. We isolated PvAsE1 through the full-length cDNA over-expression library of P. vittata and characterized it through a yeast system, RNAi gametophytes and sporophytes, subcellular-location and in situ hybridization. Phylogenomic analysis was conducted to estimate the appearance time of PvAsE1. PvAsE1 was a plasma membrane-oriented arsenite (AsIII) effluxer. The silencing of PvAsE1 reduced AsIII long-distance translocation in P. vittata sporophytes. PvAsE1 was structurally similar to solute carrier (SLC)13 proteins. Its transcripts could be observed in parenchyma cells surrounding the xylem of roots. The appearance time was estimated at c. 52.7 Ma. PvAsE1 was a previously uncharacterized SLC13-like AsIII effluxer, which may contribute to AsIII long-distance translocation via xylem loading. PvAsE1 appeared late in fern evolution and might be an adaptive subject to the selection pressure at the Cretaceaou-Paleogene boundary. The identification of PvAsE1 provides clues for revealing the special As hyperaccumulation characteristics of P. vittata.
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Affiliation(s)
- Huili Yan
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Wenxiu Xu
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Tian Zhang
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Lu Feng
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Ruoxi Liu
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Luyao Wang
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Lulu Wu
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Han Zhang
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiaohan Zhang
- College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China
| | - Ting Li
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhimei Peng
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Chen Jin
- College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China
| | - Yijun Yu
- Zhejiang Station for Management of Arable Land Quality and Fertilizer, Hangzhou, 310020, China
| | - Junai Ping
- Sorghum Research Institute of Shanxi Agricultural University, Jinzhong, 030600, China
| | - Mi Ma
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Zhenyan He
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
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13
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Sagaama A, Issaoui N, Bardak F, Al-Dossary O, Kazachenko AS, Karrouchi K, Atac A, Wojcik MJ. Non covalent interactions analysis and spectroscopic characterization combined with molecular docking study of N′-(4-Methoxybenzylidene)-5-phenyl-1H-pyrazole-3-carbohydrazide. JOURNAL OF KING SAUD UNIVERSITY - SCIENCE 2022. [DOI: 10.1016/j.jksus.2021.101778] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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14
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Lou J, Wang J, Yang Y, Yang Q, LI R, Hu M, He Q, Du J, Wang X, Li M, Yang S. Development and characterization of efficient xylose utilization strains of Zymomonas mobilis. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:231. [PMID: 34863266 PMCID: PMC8645129 DOI: 10.1186/s13068-021-02082-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 11/19/2021] [Indexed: 05/15/2023]
Abstract
BACKGROUND Efficient use of glucose and xylose is a key for the economic production of lignocellulosic biofuels and biochemicals, and different recombinant strains have been constructed for xylose utilization including those using Zymomonas mobilis as the host. However, the xylose utilization efficiency still needs to be improved. In this work, the strategy of combining metabolic engineering and adaptive laboratory evolution (ALE) was employed to develop recombinant Z. mobilis strains that can utilize xylose efficiently at high concentrations, and NGS-based genome resequencing and RNA-Seq transcriptomics were performed for strains evolved after serial transfers in different media to understand the impact of xylose and differences among strains with different xylose-utilization capabilities at molecular level. RESULTS Heterologous genes encoding xylose isomerase and xylulokinase were evaluated, which were then introduced into xylose-utilizing strain Z. mobilis 8b to enhance its capacity of xylose utilization. The results demonstrated that the effect of three xylose isomerases on xylose utilization was different, and the increase of copy number of xylose metabolism genes can improve xylose utilization. Among various recombinant strains constructed, the xylose utilization capacity of the recombinant strain 8b-RsXI-xylB was the best, which was further improved through continuous adaption with 38 transfers over 100 days in 50 g/L xylose media. The fermentation performances of the parental strain 8b, the evolved 8b-S38 strain with the best xylose utilization capability, and the intermediate strain 8b-S8 in different media were compared, and the results showed that only 8b-S38 could completely consume xylose at 50 g/L and 100 g/L concentrations. In addition, the xylose consumption rate of 8b-S38 was faster than that of 8b at different xylose concentrations from 50 to 150 g/L, and the ethanol yield increased by 16 ~ 40%, respectively. The results of the mixed-sugar fermentation also demonstrated that 8b-S38 had a higher xylose consumption rate than 8b, and its maximum ethanol productivity was 1.2 ~ 1.4 times higher than that of 8b and 8b-S8. Whole-genome resequencing identified three common genetic changes in 8b-S38 compared with 8b and 8b-S8. RNA-Seq study demonstrated that the expression levels of genes encoding chaperone proteins, ATP-dependent proteases, phage shock proteins, ribosomal proteins, flagellar operons, and transcriptional regulators were significantly increased in xylose media in 8b-S38. The up-regulated expression of these genes may therefore contribute to the efficient xylose utilization of 8b-S38 by maintaining the normal cell metabolism and growth, repairing cellular damages, and rebalancing cellular energy to help cells resist the stressful environment. CONCLUSIONS This study provides gene candidates to improve xylose utilization, and the result of expressing an extra copy of xylose isomerase and xylulokinase improved xylose utilization also provides a direction for efficient xylose-utilization strain development in other microorganisms. In addition, this study demonstrated the necessity to combine metabolic engineering and ALE for industrial strain development. The recombinant strain 8b-S38 can efficiently metabolize xylose for ethanol fermentation at high xylose concentrations as well as in mixed sugars of glucose and xylose, which could be further developed as the microbial biocatalyst for the production of lignocellulosic biofuels and biochemicals.
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Affiliation(s)
- Jiyun Lou
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Jingwen Wang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Yongfu Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Qing Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Runxia LI
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Mimi Hu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Qiaoning He
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Jun Du
- China Biotech Fermentation Industry Association, Beijing, 100833 China
| | - Xia Wang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Mian Li
- Zhejiang Huakang Pharmaceutical Co., Ltd., Kaihua County, Zhejiang, China
| | - Shihui Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, 430062 China
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15
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Thermostability-based binding assays reveal complex interplay of cation, substrate and lipid binding in the bacterial DASS transporter, VcINDY. Biochem J 2021; 478:3847-3867. [PMID: 34643224 PMCID: PMC8652582 DOI: 10.1042/bcj20210061] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Revised: 10/08/2021] [Accepted: 10/13/2021] [Indexed: 12/04/2022]
Abstract
The divalent anion sodium symporter (DASS) family of transporters (SLC13 family in humans) are key regulators of metabolic homeostasis, disruption of which results in protection from diabetes and obesity, and inhibition of liver cancer cell proliferation. Thus, DASS transporter inhibitors are attractive targets in the treatment of chronic, age-related metabolic diseases. The characterisation of several DASS transporters has revealed variation in the substrate selectivity and flexibility in the coupling ion used to power transport. Here, using the model DASS co-transporter, VcINDY from Vibrio cholerae, we have examined the interplay of the three major interactions that occur during transport: the coupling ion, the substrate, and the lipid environment. Using a series of high-throughput thermostability-based interaction assays, we have shown that substrate binding is Na+-dependent; a requirement that is orchestrated through a combination of electrostatic attraction and Na+-induced priming of the binding site architecture. We have identified novel DASS ligands and revealed that ligand binding is dominated by the requirement of two carboxylate groups in the ligand that are precisely distanced to satisfy carboxylate interaction regions of the substrate-binding site. We have also identified a complex relationship between substrate and lipid interactions, which suggests a dynamic, regulatory role for lipids in VcINDY's transport cycle.
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16
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Jaramillo-Martinez V, Sivaprakasam S, Ganapathy V, Urbatsch IL. Drosophila INDY and Mammalian INDY: Major Differences in Transport Mechanism and Structural Features despite Mostly Similar Biological Functions. Metabolites 2021; 11:metabo11100669. [PMID: 34677384 PMCID: PMC8537002 DOI: 10.3390/metabo11100669] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 09/27/2021] [Indexed: 12/12/2022] Open
Abstract
INDY (I’m Not Dead Yet) is a plasma membrane transporter for citrate, first identified in Drosophila. Partial deficiency of INDY extends lifespan in this organism in a manner similar to that of caloric restriction. The mammalian counterpart (NaCT/SLC13A5) also transports citrate. In mice, it is the total, not partial, absence of the transporter that leads to a metabolic phenotype similar to that caloric restriction; however, there is evidence for subtle neurological dysfunction. Loss-of-function mutations in SLC13A5 (solute carrier gene family 13, member A5) occur in humans, causing a recessive disease, with severe clinical symptoms manifested by neonatal seizures and marked disruption in neurological development. Though both Drosophila INDY and mammalian INDY transport citrate, the translocation mechanism differs, the former being a dicarboxylate exchanger for the influx of citrate2− in exchange for other dicarboxylates, and the latter being a Na+-coupled uniporter for citrate2−. Their structures also differ as evident from only ~35% identity in amino acid sequence and from theoretically modeled 3D structures. The varied biological consequences of INDY deficiency across species, with the beneficial effects predominating in lower organisms and detrimental effects overwhelming in higher organisms, are probably reflective of species-specific differences in tissue expression and also in relative contribution of extracellular citrate to metabolic pathways in different tissues
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Affiliation(s)
- Valeria Jaramillo-Martinez
- Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA;
| | - Sathish Sivaprakasam
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; (S.S.); (V.G.)
| | - Vadivel Ganapathy
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; (S.S.); (V.G.)
| | - Ina L. Urbatsch
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; (S.S.); (V.G.)
- Correspondence:
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17
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Consequences of NaCT/SLC13A5/mINDY deficiency: good versus evil, separated only by the blood-brain barrier. Biochem J 2021; 478:463-486. [PMID: 33544126 PMCID: PMC7868109 DOI: 10.1042/bcj20200877] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 01/07/2021] [Accepted: 01/11/2021] [Indexed: 02/08/2023]
Abstract
NaCT/SLC13A5 is a Na+-coupled transporter for citrate in hepatocytes, neurons, and testes. It is also called mINDY (mammalian ortholog of ‘I'm Not Dead Yet’ in Drosophila). Deletion of Slc13a5 in mice leads to an advantageous phenotype, protecting against diet-induced obesity, and diabetes. In contrast, loss-of-function mutations in SLC13A5 in humans cause a severe disease, EIEE25/DEE25 (early infantile epileptic encephalopathy-25/developmental epileptic encephalopathy-25). The difference between mice and humans in the consequences of the transporter deficiency is intriguing but probably explainable by the species-specific differences in the functional features of the transporter. Mouse Slc13a5 is a low-capacity transporter, whereas human SLC13A5 is a high-capacity transporter, thus leading to quantitative differences in citrate entry into cells via the transporter. These findings raise doubts as to the utility of mouse models to evaluate NaCT biology in humans. NaCT-mediated citrate entry in the liver impacts fatty acid and cholesterol synthesis, fatty acid oxidation, glycolysis, and gluconeogenesis; in neurons, this process is essential for the synthesis of the neurotransmitters glutamate, GABA, and acetylcholine. Thus, SLC13A5 deficiency protects against obesity and diabetes based on what the transporter does in hepatocytes, but leads to severe brain deficits based on what the transporter does in neurons. These beneficial versus detrimental effects of SLC13A5 deficiency are separable only by the blood-brain barrier. Can we harness the beneficial effects of SLC13A5 deficiency without the detrimental effects? In theory, this should be feasible with selective inhibitors of NaCT, which work only in the liver and do not get across the blood-brain barrier.
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18
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A home run for human NaCT/SLC13A5/INDY: cryo-EM structure and homology model to predict transport mechanisms, inhibitor interactions and mutational defects. Biochem J 2021; 478:2051-2057. [PMID: 34101804 PMCID: PMC8203205 DOI: 10.1042/bcj20210211] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 05/14/2021] [Accepted: 05/18/2021] [Indexed: 11/26/2022]
Abstract
NaCT (SLC13A5) is a Na+-coupled transporter for citrate, which is expressed in the liver, brain, testes, and bone. It is the mammalian homolog of Drosophila INDY, a cation-independent transporter for citrate, whose partial loss extends lifespan in the organism. In humans, loss-of-function mutations in NaCT cause a disease with severe neurological dysfunction, characterized by neonatal epilepsy and delayed brain development. In contrast with humans, deletion of NaCT in mice results in a beneficial metabolic phenotype with protection against diet-induced obesity and metabolic syndrome; the brain dysfunction is not readily noticeable. The disease-causing mutations are located in different regions of human NaCT protein, suggesting that different mutations might have different mechanisms for the loss of function. The beneficial effects of NaCT loss in the liver versus the detrimental effects of NaCT loss in the brain provide an opportunity to design high-affinity inhibitors for the transporter that do not cross the blood-brain barrier so that only the beneficial effects could be harnessed. To realize these goals, we need a detailed knowledge of the 3D structure of human NaCT. The recent report by Sauer et al. in Nature describing the cryo-EM structure of human NaCT represents such a milestone, paving the way for a better understanding of the structure-function relationship for this interesting and clinically important transporter.
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19
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Coleman PS, Parlo RA. Warburg's Ghost-Cancer's Self-Sustaining Phenotype: The Aberrant Carbon Flux in Cholesterol-Enriched Tumor Mitochondria via Deregulated Cholesterogenesis. Front Cell Dev Biol 2021; 9:626316. [PMID: 33777935 PMCID: PMC7994618 DOI: 10.3389/fcell.2021.626316] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 01/29/2021] [Indexed: 01/08/2023] Open
Abstract
Interpreting connections between the multiple networks of cell metabolism is indispensable for understanding how cells maintain homeostasis or transform into the decontrolled proliferation phenotype of cancer. Situated at a critical metabolic intersection, citrate, derived via glycolysis, serves as either a combustible fuel for aerobic mitochondrial bioenergetics or as a continuously replenished cytosolic carbon source for lipid biosynthesis, an essentially anaerobic process. Therein lies the paradox: under what conditions do cells control the metabolic route by which they process citrate? The Warburg effect exposes essentially the same dilemma—why do cancer cells, despite an abundance of oxygen needed for energy-generating mitochondrial respiration with citrate as fuel, avoid catabolizing mitochondrial citrate and instead rely upon accelerated glycolysis to support their energy requirements? This review details the genesis and consequences of the metabolic paradigm of a “truncated” Krebs/TCA cycle. Abundant data are presented for substrate utilization and membrane cholesterol enrichment in tumors that are consistent with criteria of the Warburg effect. From healthy cellular homeostasis to the uncontrolled proliferation of tumors, metabolic alterations center upon the loss of regulation of the cholesterol biosynthetic pathway. Deregulated tumor cholesterogenesis at the HMGR locus, generating enhanced carbon flux through the cholesterol synthesis pathway, is an absolute prerequisite for DNA synthesis and cell division. Therefore, expedited citrate efflux from cholesterol-enriched tumor mitochondria via the CTP/SLC25A1 citrate transporter is fundamental for sustaining the constant demand for cytosolic citrate that fuels the elevated flow of carbons from acetyl-CoA through the deregulated pathway of cholesterol biosynthesis.
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Affiliation(s)
| | - Risa A Parlo
- Kingsborough Community College, Brooklyn, NY, United States
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20
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Functional analysis of a species-specific inhibitor selective for human Na+-coupled citrate transporter (NaCT/SLC13A5/mINDY). Biochem J 2021; 477:4149-4165. [PMID: 33079129 PMCID: PMC7657661 DOI: 10.1042/bcj20200592] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 10/12/2020] [Accepted: 10/20/2020] [Indexed: 12/14/2022]
Abstract
The Na+-coupled citrate transporter (NaCT/SLC13A5/mINDY) in the liver delivers citrate from the blood into hepatocytes. As citrate is a key metabolite and regulator of multiple biochemical pathways, deletion of Slc13a5 in mice protects against diet-induced obesity, diabetes, and metabolic syndrome. Silencing the transporter suppresses hepatocellular carcinoma. Therefore, selective blockers of NaCT hold the potential to treat various diseases. Here we report on the characteristics of one such inhibitor, BI01383298. It is known that BI01383298 is a high-affinity inhibitor selective for human NaCT with no effect on mouse NaCT. Here we show that this compound is an irreversible and non-competitive inhibitor of human NaCT, thus describing the first irreversible inhibitor for this transporter. The mouse NaCT is not affected by this compound. The inhibition of human NaCT by BI01383298 is evident for the constitutively expressed transporter in HepG2 cells and for the ectopically expressed human NaCT in HEK293 cells. The IC50 is ∼100 nM, representing the highest potency among the NaCT inhibitors known to date. Exposure of HepG2 cells to this inhibitor results in decreased cell proliferation. We performed molecular modeling of the 3D-structures of human and mouse NaCTs using the crystal structure of a humanized variant of VcINDY as the template, and docking studies to identify the amino acid residues involved in the binding of citrate and BI01383298. These studies provide insight into the probable bases for the differential effects of the inhibitor on human NaCT versus mouse NaCT as well as for the marked species-specific difference in citrate affinity.
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21
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Sauer DB, Song J, Wang B, Hilton JK, Karpowich NK, Mindell JA, Rice WJ, Wang DN. Structure and inhibition mechanism of the human citrate transporter NaCT. Nature 2021; 591:157-161. [PMID: 33597751 PMCID: PMC7933130 DOI: 10.1038/s41586-021-03230-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 01/12/2021] [Indexed: 11/16/2022]
Abstract
Citrate is most well-known as an intermediate in the TCA cycle of the cell. In addition to this essential role in energy metabolism, the tricarboxylate anion also acts as both a precursor and a regulator of fatty acid synthesis 1–3. Thus, the rate of fatty acid synthesis correlates directly with the cytosolic citrate concentration 4,5. Liver cells import citrate via the sodium-dependent citrate transporter NaCT (SLC13A5), and as a consequence this protein is a potential target for anti-obesity drugs. To understand the structural basis of its inhibition mechanism, we have determined cryo-electron microscopy structures of human NaCT in complex with citrate and with a small molecule inhibitor. These structures reveal how the inhibitor, bound at the same site as citrate, arrests the protein’s transport cycle. The NaCT-inhibitor structure also explains why the compound selectively inhibits NaCT over two homologous human dicarboxylate transporters, and suggests ways to further improve the affinity and selectivity. Finally, the NaCT structures provide a framework for understanding how various mutations abolish NaCT’s transport activity in the brain and thereby cause SLC13A5-Epilepsy in newborns 6–8.
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Affiliation(s)
- David B Sauer
- Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY, USA.,Department of Cell Biology, New York University School of Medicine, New York, NY, USA
| | - Jinmei Song
- Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY, USA.,Department of Cell Biology, New York University School of Medicine, New York, NY, USA
| | - Bing Wang
- Cryo-Electron Microscopy Core, New York University School of Medicine, New York, NY, USA
| | - Jacob K Hilton
- Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Nathan K Karpowich
- Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY, USA.,Department of Cell Biology, New York University School of Medicine, New York, NY, USA.,Janssen Pharmaceuticals, Spring House, PA, USA
| | - Joseph A Mindell
- Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA.
| | - William J Rice
- Department of Cell Biology, New York University School of Medicine, New York, NY, USA. .,Cryo-Electron Microscopy Core, New York University School of Medicine, New York, NY, USA.
| | - Da-Neng Wang
- Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY, USA. .,Department of Cell Biology, New York University School of Medicine, New York, NY, USA.
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22
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Sampson CDD, Stewart MJ, Mindell JA, Mulligan C. Solvent accessibility changes in a Na +-dependent C 4-dicarboxylate transporter suggest differential substrate effects in a multistep mechanism. J Biol Chem 2020; 295:18524-18538. [PMID: 33087444 PMCID: PMC7939474 DOI: 10.1074/jbc.ra120.013894] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 10/06/2020] [Indexed: 11/06/2022] Open
Abstract
The divalent anion sodium symporter (DASS) family (SLC13) plays critical roles in metabolic homeostasis, influencing many processes, including fatty acid synthesis, insulin resistance, and adiposity. DASS transporters catalyze the Na+-driven concentrative uptake of Krebs cycle intermediates and sulfate into cells; disrupting their function can protect against age-related metabolic diseases and can extend lifespan. An inward-facing crystal structure and an outward-facing model of a bacterial DASS family member, VcINDY from Vibrio cholerae, predict an elevator-like transport mechanism involving a large rigid body movement of the substrate-binding site. How substrate binding influences the conformational state of VcINDY is currently unknown. Here, we probe the interaction between substrate binding and protein conformation by monitoring substrate-induced solvent accessibility changes of broadly distributed positions in VcINDY using a site-specific alkylation strategy. Our findings reveal that accessibility to all positions tested is modulated by the presence of substrates, with the majority becoming less accessible in the presence of saturating concentrations of both Na+ and succinate. We also observe separable effects of Na+ and succinate binding at several positions suggesting distinct effects of the two substrates. Furthermore, accessibility changes to a solely succinate-sensitive position suggests that substrate binding is a low-affinity, ordered process. Mapping these accessibility changes onto the structures of VcINDY suggests that Na+ binding drives the transporter into an as-yet-unidentified conformational state, involving rearrangement of the substrate-binding site-associated re-entrant hairpin loops. These findings provide insight into the mechanism of VcINDY, which is currently the only structurally characterized representative of the entire DASS family.
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Affiliation(s)
- Connor D D Sampson
- School of Biosciences, University of Kent, Canterbury, Kent, United Kingdom
| | - Matthew J Stewart
- School of Biosciences, University of Kent, Canterbury, Kent, United Kingdom
| | - Joseph A Mindell
- Membrane Transport Biophysics Section, Porter Neuroscience Research Center, NINDS, National Institutes of Health, Bethesda, Maryland, USA
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23
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Abstract
The mechanisms responsible for the trafficking of carboxylate ions across cell membranes are becoming clearer.
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Affiliation(s)
- Adam W Duster
- Department of Integrative Biology, University of Colorado Denver, Denver, United States
| | - Hai Lin
- Chemistry Department, University of Colorado Denver, Denver, United States
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24
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Jaramillo-Martinez V, Urbatsch IL, Ganapathy V. Functional Distinction between Human and Mouse Sodium-Coupled Citrate Transporters and Its Biologic Significance: An Attempt for Structural Basis Using a Homology Modeling Approach. Chem Rev 2020; 121:5359-5377. [PMID: 33040525 DOI: 10.1021/acs.chemrev.0c00529] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
NaCT (SLC13A5; mINDY), a sodium-coupled citrate transporter, is the mammalian ortholog of Drosophila INDY. Loss-of-function mutations in human NaCT cause severe complications with neonatal epilepsy and encephalopathy (EIEE25). Surprisingly, mice lacking this transporter do not have this detrimental brain phenotype. The marked differences in transport kinetics between mouse and human NaCTs provide at least a partial explanation for this conundrum, but a structural basis for the differences is lacking. Neither human nor mouse NaCT has been crystallized, and any information known on their structures is based entirely on what was inferred from the structure of VcINDY, a related transporter in bacteria. Here, we highlight the functional features of human and mouse NaCTs and provide a plausible molecular basis for the differences based on a full-length homology modeling approach. The transport characteristics of human NaCT markedly differ from those of VcINDY. Therefore, the modeling with VcINDY as the template is flawed, but this is the best available option at this time. With the newly deduced model, we determined the likely locations of the disease-causing mutations and propose a new classification for the mutations based on their location and potential impact on transport function. This new information should pave the way for future design and development of novel therapeutics to restore the lost function of the mutant transporters as a treatment strategy for patients with EIEE25.
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Affiliation(s)
- Valeria Jaramillo-Martinez
- Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, Lubbock, Texas 79430, United States
| | - Ina L Urbatsch
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas 79430, United States.,Center for Membrane Protein Research and Center of Excellence for Translational Neuroscience and Therapeutics, Texas Tech University Health Sciences Center, Lubbock, Texas 79430, United States
| | - Vadivel Ganapathy
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas 79430, United States.,Center for Membrane Protein Research and Center of Excellence for Translational Neuroscience and Therapeutics, Texas Tech University Health Sciences Center, Lubbock, Texas 79430, United States
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25
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Sauer DB, Trebesch N, Marden JJ, Cocco N, Song J, Koide A, Koide S, Tajkhorshid E, Wang DN. Structural basis for the reaction cycle of DASS dicarboxylate transporters. eLife 2020; 9:e61350. [PMID: 32869741 PMCID: PMC7553777 DOI: 10.7554/elife.61350] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 08/31/2020] [Indexed: 01/09/2023] Open
Abstract
Citrate, α-ketoglutarate and succinate are TCA cycle intermediates that also play essential roles in metabolic signaling and cellular regulation. These di- and tricarboxylates are imported into the cell by the divalent anion sodium symporter (DASS) family of plasma membrane transporters, which contains both cotransporters and exchangers. While DASS proteins transport substrates via an elevator mechanism, to date structures are only available for a single DASS cotransporter protein in a substrate-bound, inward-facing state. We report multiple cryo-EM and X-ray structures in four different states, including three hitherto unseen states, along with molecular dynamics simulations, of both a cotransporter and an exchanger. Comparison of these outward- and inward-facing structures reveal how the transport domain translates and rotates within the framework of the scaffold domain through the transport cycle. Additionally, we propose that DASS transporters ensure substrate coupling by a charge-compensation mechanism, and by structural changes upon substrate release.
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Affiliation(s)
- David B Sauer
- Skirball Institute of Biomolecular Medicine, New York University School of MedicineNew YorkUnited States
- Department of Cell Biology, New York University School of MedicineNew YorkUnited States
| | - Noah Trebesch
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, and Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-ChampaignUrbanaUnited States
| | - Jennifer J Marden
- Skirball Institute of Biomolecular Medicine, New York University School of MedicineNew YorkUnited States
- Department of Cell Biology, New York University School of MedicineNew YorkUnited States
| | - Nicolette Cocco
- Skirball Institute of Biomolecular Medicine, New York University School of MedicineNew YorkUnited States
- Department of Cell Biology, New York University School of MedicineNew YorkUnited States
| | - Jinmei Song
- Skirball Institute of Biomolecular Medicine, New York University School of MedicineNew YorkUnited States
- Department of Cell Biology, New York University School of MedicineNew YorkUnited States
| | - Akiko Koide
- Perlmutter Cancer Center, New York University School of MedicineNew YorkUnited States
- Department of Medicine, New York University School of MedicineNew YorkUnited States
| | - Shohei Koide
- Perlmutter Cancer Center, New York University School of MedicineNew YorkUnited States
- Department of Medicine, New York University School of MedicineNew YorkUnited States
- Department of Biochemistry and Molecular Pharmacology, New York University School of MedicineNew YorkUnited States
| | - Emad Tajkhorshid
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, and Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-ChampaignUrbanaUnited States
| | - Da-Neng Wang
- Skirball Institute of Biomolecular Medicine, New York University School of MedicineNew YorkUnited States
- Department of Cell Biology, New York University School of MedicineNew YorkUnited States
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26
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Khamaysi A, Aharon S, Eini-Rider H, Ohana E. A dynamic anchor domain in slc13 transporters controls metabolite transport. J Biol Chem 2020; 295:8155-8163. [PMID: 32152229 DOI: 10.1074/jbc.ra119.010911] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 02/26/2020] [Indexed: 12/11/2022] Open
Abstract
Metabolite transport across cellular membranes is required for bioenergetic processes and metabolic signaling. The solute carrier family 13 (slc13) transporters mediate transport of the metabolites succinate and citrate and hence are of paramount physiological importance. Nevertheless, the mechanisms of slc13 transport and regulation are poorly understood. Here, a dynamic structural slc13 model suggested that an interfacial helix, H4c, which is common to all slc13s, stabilizes the stationary scaffold domain by anchoring it to the membrane, thereby facilitating movement of the SLC13 catalytic domain. Moreover, we found that intracellular determinants interact with the H4c anchor domain to modulate transport. This dual function is achieved by basic residues that alternately face either the membrane phospholipids or the intracellular milieu. This mechanism was supported by several experimental findings obtained using biochemical methods, electrophysiological measurements in Xenopus oocytes, and fluorescent microscopy of mammalian cells. First, a positively charged and highly conserved H4c residue, Arg108, was indispensable and crucial for metabolite transport. Furthermore, neutralization of other H4c basic residues inhibited slc13 transport function, thus mimicking the inhibitory effect of the slc13 inhibitor, slc26a6. Our findings suggest that the positive charge distribution across H4c domain controls slc13 transporter function and is utilized by slc13-interacting proteins in the regulation of metabolite transport.
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Affiliation(s)
- Ahlam Khamaysi
- Department of Clinical Biochemistry and Pharmacology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
| | - Sara Aharon
- Department of Clinical Biochemistry and Pharmacology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
| | - Hadar Eini-Rider
- Department of Clinical Biochemistry and Pharmacology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
| | - Ehud Ohana
- Department of Clinical Biochemistry and Pharmacology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
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27
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Zhou W, Fiorin G, Anselmi C, Karimi-Varzaneh HA, Poblete H, Forrest LR, Faraldo-Gómez JD. Large-scale state-dependent membrane remodeling by a transporter protein. eLife 2019; 8:50576. [PMID: 31855177 PMCID: PMC6957315 DOI: 10.7554/elife.50576] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 12/17/2019] [Indexed: 12/22/2022] Open
Abstract
That channels and transporters can influence the membrane morphology is increasingly recognized. Less appreciated is that the extent and free-energy cost of these deformations likely varies among different functional states of a protein, and thus, that they might contribute significantly to defining its mechanism. We consider the trimeric Na+-aspartate symporter GltPh, a homolog of an important class of neurotransmitter transporters, whose mechanism entails one of the most drastic structural changes known. Molecular simulations indicate that when the protomers become inward-facing, they cause deep, long-ranged, and yet mutually-independent membrane deformations. Using a novel simulation methodology, we estimate that the free-energy cost of this membrane perturbation is in the order of 6–7 kcal/mol per protomer. Compensating free-energy contributions within the protein or its environment must thus stabilize this inward-facing conformation for the transporter to function. We discuss these striking results in the context of existing experimental observations for this and other transporters.
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Affiliation(s)
- Wenchang Zhou
- Theoretical Molecular Biophysics Laboratory, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, United States
| | - Giacomo Fiorin
- Theoretical Molecular Biophysics Laboratory, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, United States
| | - Claudio Anselmi
- Theoretical Molecular Biophysics Laboratory, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, United States
| | - Hossein Ali Karimi-Varzaneh
- Computational Structural Biology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
| | - Horacio Poblete
- Theoretical Molecular Biophysics Laboratory, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, United States.,Computational Structural Biology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
| | - Lucy R Forrest
- Computational Structural Biology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
| | - José D Faraldo-Gómez
- Theoretical Molecular Biophysics Laboratory, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, United States
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28
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Kardos J, Dobolyi Á, Szabó Z, Simon Á, Lourmet G, Palkovits M, Héja L. Molecular Plasticity of the Nucleus Accumbens Revisited-Astrocytic Waves Shall Rise. Mol Neurobiol 2019; 56:7950-7965. [PMID: 31134458 PMCID: PMC6834761 DOI: 10.1007/s12035-019-1641-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 05/06/2019] [Indexed: 12/11/2022]
Abstract
Part of the ventral striatal division, the nucleus accumbens (NAc) drives the circuit activity of an entire macrosystem about reward like a "flagship," signaling and leading diverse conducts. Accordingly, NAc neurons feature complex inhibitory phenotypes that assemble to process circuit inputs and generate outputs by exploiting specific arrays of opposite and/or parallel neurotransmitters, neuromodulatory peptides. The resulting complex combinations enable versatile yet specific forms of accumbal circuit plasticity, including maladaptive behaviors. Although reward signaling and behavior are elaborately linked to neuronal circuit activities, it is plausible to propose whether these neuronal ensembles and synaptic islands can be directly controlled by astrocytes, a powerful modulator of neuronal activity. Pioneering studies showed that astrocytes in the NAc sense citrate cycle metabolites and/or ATP and may induce recurrent activation. We argue that the astrocytic calcium, GABA, and Glu signaling and altered sodium and chloride dynamics fundamentally shape metaplasticity by providing active regulatory roles in the synapse- and network-level flexibility of the NAc.
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Affiliation(s)
- Julianna Kardos
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, Budapest, 1117, Hungary.
| | - Árpád Dobolyi
- Laboratory of Neuromorphology, Department of Anatomy, Histology and Embryology, Semmelweis University, Üllői út 26, Budapest, 1086, Hungary
- MTA-ELTE Laboratory of Molecular and Systems Neurobiology, Department of Physiology and Neurobiology, Eötvös Loránd University and the Hungarian Academy of Sciences, Pázmány Péter sétány 1C, Budapest, 1117, Hungary
| | - Zsolt Szabó
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, Budapest, 1117, Hungary
| | - Ágnes Simon
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, Budapest, 1117, Hungary
| | - Guillaume Lourmet
- Laboratory of Neuromorphology, Department of Anatomy, Histology and Embryology, Semmelweis University, Üllői út 26, Budapest, 1086, Hungary
| | - Miklós Palkovits
- Human Brain Tissue Bank, Semmelweis University, Tűzoltó utca 58, Budapest, H-1094, Hungary
| | - László Héja
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, Budapest, 1117, Hungary
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29
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Dewulf JP, Wiame E, Dorboz I, Elmaleh-Bergès M, Imbard A, Dumitriu D, Rak M, Bourillon A, Helaers R, Malla A, Renaldo F, Boespflug-Tanguy O, Vincent MF, Benoist JF, Wevers RA, Schlessinger A, Van Schaftingen E, Nassogne MC, Schiff M. SLC13A3 variants cause acute reversible leukoencephalopathy and α-ketoglutarate accumulation. Ann Neurol 2019; 85:385-395. [PMID: 30635937 DOI: 10.1002/ana.25412] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 01/08/2019] [Accepted: 01/08/2019] [Indexed: 01/22/2023]
Abstract
OBJECTIVE SLC13A3 encodes the plasma membrane Na+ /dicarboxylate cotransporter 3, which imports inside the cell 4 to 6 carbon dicarboxylates as well as N-acetylaspartate (NAA). SLC13A3 is mainly expressed in kidney, in astrocytes, and in the choroid plexus. We describe two unrelated patients presenting with acute, reversible (and recurrent in one) neurological deterioration during a febrile illness. Both patients exhibited a reversible leukoencephalopathy and a urinary excretion of α-ketoglutarate (αKG) that was markedly increased and persisted over time. In one patient, increased concentrations of cerebrospinal fluid NAA and dicarboxylates (including αKG) were observed. Extensive workup was unsuccessful, and a genetic cause was suspected. METHODS Whole exome sequencing (WES) was performed. Our teams were connected through GeneMatcher. RESULTS WES analysis revealed variants in SLC13A3. A homozygous missense mutation (p.Ala254Asp) was found in the first patient. The second patient was heterozygous for another missense mutation (p.Gly548Ser) and an intronic mutation affecting splicing as demonstrated by reverse transcriptase polymerase chain reaction performed in muscle tissue (c.1016 + 3A > G). Mutations and segregation were confirmed by Sanger sequencing. Functional studies performed on HEK293T cells transiently transfected with wild-type and mutant SLC13A3 indicated that the missense mutations caused a marked reduction in the capacity to transport αKG, succinate, and NAA. INTERPRETATION SLC13A3 deficiency causes acute and reversible leukoencephalopathy with marked accumulation of αKG. Urine organic acids (especially αKG and NAA) and SLC13A3 mutations should be screened in patients presenting with unexplained reversible leukoencephalopathy, for which SLC13A3 deficiency is a novel differential diagnosis. ANN NEUROL 2019;85:385-395.
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Affiliation(s)
- Joseph P Dewulf
- Laboratory of Physiological Chemistry, de Duve Institute, Université catholique de Louvain, Brussels, Belgium.,Walloon Excellence in Life Sciences and Biotechnology (WELBIO), Brussels, Belgium.,Department of Laboratory Medicine, Cliniques universitaires Saint-Luc, Université catholique de Louvain, Brussels, Belgium
| | - Elsa Wiame
- Laboratory of Physiological Chemistry, de Duve Institute, Université catholique de Louvain, Brussels, Belgium.,Walloon Excellence in Life Sciences and Biotechnology (WELBIO), Brussels, Belgium
| | - Imen Dorboz
- UMR1141, PROTECT, INSERM, Paris Diderot University, Sorbonne Paris Cité, Paris, France
| | - Monique Elmaleh-Bergès
- Department of Pediatric Imaging, Robert Debré University Hospital, Public APHP, Paris, France
| | - Apolline Imbard
- Laboratory of Biochemistry, Robert Debré University Hospital, APHP, France.,Paris-Sud University, Châtenay-Malabry, France
| | - Dana Dumitriu
- Department of Pediatric Imaging, Cliniques universitaires Saint-Luc, Université catholique de Louvain, Brussels, Belgium
| | - Malgorzata Rak
- UMR1141, PROTECT, INSERM, Paris Diderot University, Sorbonne Paris Cité, Paris, France
| | - Agnès Bourillon
- Laboratory of Biochemistry, Robert Debré University Hospital, APHP, France.,Paris-Sud University, Châtenay-Malabry, France
| | - Raphaël Helaers
- Human Molecular Genetics, de Duve Institute, Université catholique de Louvain, Brussels, Belgium
| | - Alisha Malla
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Florence Renaldo
- UMR1141, PROTECT, INSERM, Paris Diderot University, Sorbonne Paris Cité, Paris, France.,Department of Pediatric Neurology and Metabolic Diseases, Robert Debré University Hospital, APHP, Paris, France.,Reference Center for Leukodystrophies and Rare Leukoencephalopathies, LEUKOFRANCE, Robert Debré University Hospital, APHP, Paris, France
| | - Odile Boespflug-Tanguy
- UMR1141, PROTECT, INSERM, Paris Diderot University, Sorbonne Paris Cité, Paris, France.,Department of Pediatric Neurology and Metabolic Diseases, Robert Debré University Hospital, APHP, Paris, France.,Reference Center for Leukodystrophies and Rare Leukoencephalopathies, LEUKOFRANCE, Robert Debré University Hospital, APHP, Paris, France
| | - Marie-Françoise Vincent
- Department of Laboratory Medicine, Cliniques universitaires Saint-Luc, Université catholique de Louvain, Brussels, Belgium
| | - Jean-François Benoist
- Laboratory of Biochemistry, Robert Debré University Hospital, APHP, France.,Paris-Sud University, Châtenay-Malabry, France
| | - Ron A Wevers
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Avner Schlessinger
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Emile Van Schaftingen
- Laboratory of Physiological Chemistry, de Duve Institute, Université catholique de Louvain, Brussels, Belgium.,Walloon Excellence in Life Sciences and Biotechnology (WELBIO), Brussels, Belgium
| | - Marie-Cécile Nassogne
- Pediatric Neurology Unit, Cliniques universitaires Saint-Luc, Université catholique de Louvain, Brussels, Belgium
| | - Manuel Schiff
- UMR1141, PROTECT, INSERM, Paris Diderot University, Sorbonne Paris Cité, Paris, France.,Department of Pediatric Neurology and Metabolic Diseases, Robert Debré University Hospital, APHP, Paris, France.,Reference Center for Inborn Errors of Metabolism, Robert Debré University Hospital, APHP, Paris, France
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Structure and Mechanism of the Divalent Anion/Na⁺ Symporter. Int J Mol Sci 2019; 20:ijms20020440. [PMID: 30669552 PMCID: PMC6359215 DOI: 10.3390/ijms20020440] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 01/14/2019] [Accepted: 01/18/2019] [Indexed: 12/22/2022] Open
Abstract
Integral membrane proteins of the divalent anion/Na⁺ symporter (DASS) family are conserved from bacteria to humans. DASS proteins typically mediate the coupled uptake of Na⁺ ions and dicarboxylate, tricarboxylate, or sulfate. Since the substrates for DASS include key intermediates and regulators of energy metabolism, alterations of DASS function profoundly affect fat storage, energy expenditure and life span. Furthermore, loss-of-function mutations in a human DASS have been associated with neonatal epileptic encephalopathy. More recently, human DASS has also been implicated in the development of liver cancers. Therefore, human DASS proteins are potentially promising pharmacological targets for battling obesity, diabetes, kidney stone, fatty liver, as well as other metabolic and neurological disorders. Despite its clinical relevance, the mechanism by which DASS proteins recognize and transport anionic substrates remains unclear. Recently, the crystal structures of a bacterial DASS and its humanized variant have been published. This article reviews the mechanistic implications of these structures and suggests future work to better understand how the function of DASS can be modulated for potential therapeutic benefit.
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Willmes DM, Kurzbach A, Henke C, Schumann T, Zahn G, Heifetz A, Jordan J, Helfand SL, Birkenfeld AL. The longevity gene INDY ( I 'm N ot D ead Y et) in metabolic control: Potential as pharmacological target. Pharmacol Ther 2018; 185:1-11. [DOI: 10.1016/j.pharmthera.2017.10.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Colas C, Schlessinger A, Pajor AM. Mapping Functionally Important Residues in the Na +/Dicarboxylate Cotransporter, NaDC1. Biochemistry 2017; 56:4432-4441. [PMID: 28731330 DOI: 10.1021/acs.biochem.7b00503] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Transporters from the SLC13 family couple the transport of two to four Na+ ions with a di- or tricarboxylate, such as succinate or citrate. We have previously modeled mammalian members of the SLC13 family, including the Na+/dicarboxylate cotransporter NaDC1 (SLC13A2), based on a structure of the bacterial homologue VcINDY in an inward-facing conformation with one sodium ion bound at the Na1 site. In the study presented here, we modeled the outward-facing conformation of rabbit and human NaDC1 (rbNaDC1 and hNaDC1, respectively) using an outward-facing model of VcINDY as a template and identified residues in or near the putative Na2 and Na3 cation binding sites. Guided by the structural models in both conformations, we performed site-directed mutagenesis in rbNaDC1 for residues proposed to be in the Na+ or substrate binding sites. Cysteine substitution of T474 in the predicted Na2 binding site results in an inactive protein. The M539C mutant has a low apparent affinity for both sodium and lithium cations, suggesting that M539 may form part of the putative Na3 binding site. The Y432C and T86C mutants have increased Km values for succinate, supporting their proposed location in the outward-facing substrate binding site. In addition, cysteine labeling by MTSEA-biotin shows that Y432C is accessible from the outside of the cell, and the accessibility changes in the presence or absence of Na+. The results of this study improve our understanding of substrate and ion recognition in the mammalian members of the SLC13 family and provide a framework for developing conformationally specific inhibitors against these transporters.
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Affiliation(s)
- Claire Colas
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai , New York, New York 10029, United States
| | - Avner Schlessinger
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai , New York, New York 10029, United States
| | - Ana M Pajor
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California-San Diego , La Jolla, California 92130-0714, United States
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