1
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Srivastava DK, Navratna V, Tosh DK, Chinn A, Sk MF, Tajkhorshid E, Jacobson KA, Gouaux E. Structure of the human dopamine transporter and mechanisms of inhibition. Nature 2024; 632:672-677. [PMID: 39112705 PMCID: PMC11324517 DOI: 10.1038/s41586-024-07739-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 06/19/2024] [Indexed: 08/16/2024]
Abstract
The neurotransmitter dopamine has central roles in mood, appetite, arousal and movement1. Despite its importance in brain physiology and function, and as a target for illicit and therapeutic drugs, the human dopamine transporter (hDAT) and mechanisms by which it is inhibited by small molecules and Zn2+ are without a high-resolution structural context. Here we determine the structure of hDAT in a tripartite complex with the competitive inhibitor and cocaine analogue, (-)-2-β-carbomethoxy-3-β-(4-fluorophenyl)tropane2 (β-CFT), the non-competitive inhibitor MRS72923 and Zn2+ (ref. 4). We show how β-CFT occupies the central site, approximately halfway across the membrane, stabilizing the transporter in an outward-open conformation. MRS7292 binds to a structurally uncharacterized allosteric site, adjacent to the extracellular vestibule, sequestered underneath the extracellular loop 4 (EL4) and adjacent to transmembrane helix 1b (TM1b), acting as a wedge, precluding movement of TM1b and closure of the extracellular gate. A Zn2+ ion further stabilizes the outward-facing conformation by coupling EL4 to EL2, TM7 and TM8, thus providing specific insights into how Zn2+ restrains the movement of EL4 relative to EL2 and inhibits transport activity.
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Affiliation(s)
| | - Vikas Navratna
- Vollum Institute, Oregon Health and Science University, Portland, OR, USA
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Dilip K Tosh
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Audrey Chinn
- Vollum Institute, Oregon Health and Science University, Portland, OR, USA
| | - Md Fulbabu Sk
- Theoretical and Computational Biophysics Group, NIH Center for Macromolecular Modeling and Visualization, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Department of Biochemistry University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Emad Tajkhorshid
- Theoretical and Computational Biophysics Group, NIH Center for Macromolecular Modeling and Visualization, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Department of Biochemistry University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Kenneth A Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA.
| | - Eric Gouaux
- Vollum Institute, Oregon Health and Science University, Portland, OR, USA.
- Howard Hughes Medical Institute, Oregon Health and Science University, Portland, OR, USA.
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2
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de Carvalho GA, Tambwe PM, Nascimento LRC, Campos BKP, Chiareli RA, Junior GPN, Menegatti R, Gomez RS, Pinto MCX. In silico evidence of bitopertin's broad interactions within the SLC6 transporter family. J Pharm Pharmacol 2024:rgae051. [PMID: 38982944 DOI: 10.1093/jpp/rgae051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Accepted: 04/16/2024] [Indexed: 07/11/2024]
Abstract
The Glycine Transporter Type 1 (GlyT1) significantly impacts central nervous system functions, influencing glycinergic and glutamatergic neurotransmission. Bitopertin, the first GlyT1 inhibitor in clinical trials, was developed for schizophrenia treatment but showed limited efficacy. Despite this, bitopertin's repositioning could advance treating various pathologies. This study aims to understand bitopertin's mechanism of action using computational methods, exploring off-target effects, and providing a comprehensive pharmacological profile. Similarity Ensemble Approach (SEA) and SwissTargetPrediction initially predicted targets, followed by molecular modeling on SWISS-MODEL and GalaxyWeb servers. Binding sites were identified using PrankWeb, and molecular docking was performed with DockThor and GOLD software. Molecular dynamics analyses were conducted on the Visual Dynamics platform. Reverse screening on SEA and SwissTargetPrediction identified GlyT1 (SLC6A9), GlyT2 (SLC6A5), PROT (SLC6A7), and DAT (SLC6A3) as potential bitopertin targets. Homology modeling on SwissModel generated high-resolution models, optimized further on GalaxyWeb. PrankWeb identified similar binding sites in GlyT1, GlyT2, PROT, and DAT, indicating potential interaction. Docking studies suggested bitopertin's interaction with GlyT1 and proximity to GlyT2 and PROT. Molecular dynamics confirmed docking results, highlighting bitopertin's target stability beyond GlyT1. The study concludes that bitopertin potentially interacts with multiple SLC6 family targets, indicating a broader pharmacological property.
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Affiliation(s)
- Gustavo Almeida de Carvalho
- Departamento de Farmacologia, Instituto de Ciências Biológicas, Universidade Federal de Goiás, CEP 74690-900, Goiânia-GO, Brazil
| | - Paul Magogo Tambwe
- Departamento de Farmacologia, Instituto de Ciências Biológicas, Universidade Federal de Goiás, CEP 74690-900, Goiânia-GO, Brazil
| | - Lucas Rodrigues Couto Nascimento
- Departamento de Farmacologia, Instituto de Ciências Biológicas, Universidade Federal de Goiás, CEP 74690-900, Goiânia-GO, Brazil
| | - Bruna Kelly Pedrosa Campos
- Departamento de Farmacologia, Instituto de Ciências Biológicas, Universidade Federal de Goiás, CEP 74690-900, Goiânia-GO, Brazil
| | - Raphaela Almeida Chiareli
- Departamento de Farmacologia, Instituto de Ciências Biológicas, Universidade Federal de Goiás, CEP 74690-900, Goiânia-GO, Brazil
| | - Guilhermino Pereira Nunes Junior
- Departamento de Farmacologia, Instituto de Ciências Biológicas, Universidade Federal de Goiás, CEP 74690-900, Goiânia-GO, Brazil
| | - Ricardo Menegatti
- Faculdade de Farmácia, Universidade Federal de Goiás, Rua 240, Setor Leste Universitário, 74605170 - Goiânia, GO, Brazil
| | - Renato Santiago Gomez
- Departamento de Cirurgia, Faculdade de Medicina, Universidade Federal de Minas Gerais, Av. Alfredo Balena, 190, 30130-100, Belo Horizonte-MG, Brazil
| | - Mauro Cunha Xavier Pinto
- Departamento de Farmacologia, Instituto de Ciências Biológicas, Universidade Federal de Goiás, CEP 74690-900, Goiânia-GO, Brazil
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3
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Zhekova HR, Ramirez Echemendía DP, Sejdiu BI, Pushkin A, Tieleman DP, Kurtz I. Molecular dynamics simulations of lipid-protein interactions in SLC4 proteins. Biophys J 2024; 123:1705-1721. [PMID: 38760929 PMCID: PMC11214021 DOI: 10.1016/j.bpj.2024.05.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 04/09/2024] [Accepted: 05/14/2024] [Indexed: 05/20/2024] Open
Abstract
The SLC4 family of secondary bicarbonate transporters is responsible for the transport of HCO3-, CO32-, Cl-, Na+, K+, NH3, and H+, which are necessary for regulation of pH and ion homeostasis. They are widely expressed in numerous tissues throughout the body and function in different cell types with different membrane properties. Potential lipid roles in SLC4 function have been reported in experimental studies, focusing mostly on two members of the family: AE1 (Cl-/HCO3- exchanger) and NBCe1 (Na+-CO32-cotransporter). Previous computational studies of the outward-facing state of AE1 with model lipid membranes revealed enhanced protein-lipid interactions between cholesterol (CHOL) and phosphatidylinositol bisphosphate (PIP2). However, the protein-lipid interactions in other members of the family and other conformation states are still poorly understood and this precludes the detailed studies of a potential regulatory role for lipids in the SLC4 family. In this work, we performed coarse-grained and atomistic molecular dynamics simulations on three members of the SLC4 family with different transport modes: AE1, NBCe1, and NDCBE (an Na+-CO32-/Cl- exchanger), in model HEK293 membranes consisting of CHOL, PIP2, phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, and sphingomyelin. The recently resolved inward-facing state of AE1 was also included in the simulations. Lipid-protein contact analysis of the simulated trajectories was performed with the ProLint server, which provides a multitude of visualization tools for illustration of areas of enhanced lipid-protein contact and identification of putative lipid binding sites within the protein matrix. We observed enrichment of CHOL and PIP2 around all proteins with subtle differences in their distribution depending on the protein type and conformation state. Putative binding sites were identified for CHOL, PIP2, phosphatidylcholine, and sphingomyelin in the three studied proteins, and their potential roles in the SLC4 transport function, conformational transition, and protein dimerization are discussed.
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Affiliation(s)
- Hristina R Zhekova
- Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Daniel P Ramirez Echemendía
- Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Besian I Sejdiu
- Department of Structural Biology and Center of Excellence for Data Driven Discovery, St Jude Children's Research Hospital, Memphis, Tennessee
| | - Alexander Pushkin
- Department of Medicine, Division of Nephrology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
| | - D Peter Tieleman
- Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada.
| | - Ira Kurtz
- Department of Medicine, Division of Nephrology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California; Brain Research Institute, University of California, Los Angeles, Los Angeles, California.
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4
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Ni C, Hong M. Oligomerization of drug transporters: Forms, functions, and mechanisms. Acta Pharm Sin B 2024; 14:1924-1938. [PMID: 38799641 PMCID: PMC11119549 DOI: 10.1016/j.apsb.2024.01.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 12/07/2023] [Accepted: 01/05/2024] [Indexed: 05/29/2024] Open
Abstract
Drug transporters are essential players in the transmembrane transport of a wide variety of clinical drugs. The broad substrate spectra and versatile distribution pattern of these membrane proteins infer their pharmacological and clinical significance. With our accumulating knowledge on the three-dimensional structure of drug transporters, their oligomerization status has become a topic of intense study due to the possible functional roles carried out by such kind of post-translational modification (PTM). In-depth studies of oligomeric complexes formed among drug transporters as well as their interactions with other regulatory proteins can help us better understand the regulatory mechanisms of these membrane proteins, provide clues for the development of novel drugs, and improve the therapeutic efficacy. In this review, we describe different oligomerization forms as well as their structural basis of major drug transporters in the ATP-binding cassette and solute carrier superfamilies, summarize our current knowledge on the influence of oligomerization for protein expression level and transport function of these membrane proteins, and discuss the regulatory mechanisms of oligomerization. Finally, we highlight the challenges associated with the current oligomerization studies and propose some thoughts on the pharmaceutical application of this important drug transporter PTM.
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Affiliation(s)
- Chunxu Ni
- College of Life Sciences, South China Agricultural University, Guangzhou 510642, China
| | - Mei Hong
- College of Life Sciences, South China Agricultural University, Guangzhou 510642, China
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, South China Agricultural University, Guangzhou 510642, China
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5
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Chen S, Huang X, Zhang X, Li C, Zhang YW. A Conserved Intramolecular Ion-Pair Plays a Critical but Divergent Role in Regulation of Dimerization and Transport Function among the Monoamine Transporters. Int J Mol Sci 2024; 25:4032. [PMID: 38612840 PMCID: PMC11011927 DOI: 10.3390/ijms25074032] [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: 01/30/2024] [Revised: 03/26/2024] [Accepted: 04/02/2024] [Indexed: 04/14/2024] Open
Abstract
The monoamine transporters, including the serotonin transporter (SERT), dopamine transporter (DAT), and norepinephrine transporter (NET), are the therapeutic targets for the treatment of many neuropsychiatric disorders. Despite significant progress in characterizing the structures and transport mechanisms of these transporters, the regulation of their transport functions through dimerization or oligomerization remains to be understood. In the present study, we identified a conserved intramolecular ion-pair at the third extracellular loop (EL3) connecting TM5 and TM6 that plays a critical but divergent role in the modulation of dimerization and transport functions among the monoamine transporters. The disruption of the ion-pair interactions by mutations induced a significant spontaneous cross-linking of a cysteine mutant of SERT and an increase in cell surface expression but with an impaired specific transport activity. On the other hand, similar mutations of the corresponding ion-pair residues in both DAT and NET resulted in an opposite effect on their oxidation-induced dimerization, cell surface expression, and transport function. Reversible biotinylation experiments indicated that the ion-pair mutations slowed down the internalization of SERT but stimulated the internalization of DAT. In addition, cysteine accessibility measurements for monitoring SERT conformational changes indicated that substitution of the ion-pair residues resulted in profound effects on the rate constants for cysteine modification in both the extracellular and cytoplasmatic substrate permeation pathways. Furthermore, molecular dynamics simulations showed that the ion-pair mutations increased the interfacial interactions in a SERT dimer but decreased it in a DAT dimer. Taken together, we propose that the transport function is modulated by the equilibrium between monomers and dimers on the cell surface, which is regulated by a potential compensatory mechanism but with different molecular solutions among the monoamine transporters. The present study provided new insights into the structural elements regulating the transport function of the monoamine transporters through their dimerization.
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Affiliation(s)
| | | | | | | | - Yuan-Wei Zhang
- School of Life Sciences, Guangzhou University, Guangzhou 510006, China; (S.C.); (X.H.); (X.Z.); (C.L.)
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6
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Kalinichenko L, Kornhuber J, Sinning S, Haase J, Müller CP. Serotonin Signaling through Lipid Membranes. ACS Chem Neurosci 2024; 15:1298-1320. [PMID: 38499042 PMCID: PMC10995955 DOI: 10.1021/acschemneuro.3c00823] [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: 12/20/2023] [Revised: 02/22/2024] [Accepted: 02/27/2024] [Indexed: 03/20/2024] Open
Abstract
Serotonin (5-HT) is a vital modulatory neurotransmitter responsible for regulating most behaviors in the brain. An inefficient 5-HT synaptic function is often linked to various mental disorders. Primarily, membrane proteins controlling the expression and activity of 5-HT synthesis, storage, release, receptor activation, and inactivation are critical to 5-HT signaling in synaptic and extra-synaptic sites. Moreover, these signals represent information transmission across membranes. Although the lipid membrane environment is often viewed as fairly stable, emerging research suggests significant functional lipid-protein interactions with many synaptic 5-HT proteins. These protein-lipid interactions extend to almost all the primary lipid classes that form the plasma membrane. Collectively, these lipid classes and lipid-protein interactions affect 5-HT synaptic efficacy at the synapse. The highly dynamic lipid composition of synaptic membranes suggests that these lipids and their interactions with proteins may contribute to the plasticity of the 5-HT synapse. Therefore, this broader protein-lipid model of the 5-HT synapse necessitates a reconsideration of 5-HT's role in various associated mental disorders.
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Affiliation(s)
- Liubov
S. Kalinichenko
- Department
of Psychiatry and Psychotherapy, University
Clinic, Friedrich-Alexander-University of Erlangen-Nürnberg, Schwabachanlage 6, 91054, Erlangen, Germany
| | - Johannes Kornhuber
- Department
of Psychiatry and Psychotherapy, University
Clinic, Friedrich-Alexander-University of Erlangen-Nürnberg, Schwabachanlage 6, 91054, Erlangen, Germany
| | - Steffen Sinning
- Department
of Forensic Medicine, Aarhus University, Palle Juul-Jensens Boulevard 99, 8200 Aarhus N, Denmark
| | - Jana Haase
- School
of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, Dublin, Ireland
| | - Christian P. Müller
- Department
of Psychiatry and Psychotherapy, University
Clinic, Friedrich-Alexander-University of Erlangen-Nürnberg, Schwabachanlage 6, 91054, Erlangen, Germany
- Institute
of Psychopharmacology, Central Institute of Mental Health, Medical
Faculty Mannheim, Heidelberg University, 69047, Mannheim, Germany
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7
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Vaughan RA, Henry LK, Foster JD, Brown CR. Post-translational mechanisms in psychostimulant-induced neurotransmitter efflux. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2024; 99:1-33. [PMID: 38467478 DOI: 10.1016/bs.apha.2023.10.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/13/2024]
Abstract
The availability of monoamine neurotransmitters in the brain is under the control of dopamine, norepinephrine, and serotonin transporters expressed on the plasma membrane of monoaminergic neurons. By regulating transmitter levels these proteins mediate crucial functions including cognition, attention, and reward, and dysregulation of their activity is linked to mood and psychiatric disorders of these systems. Amphetamine-based transporter substrates stimulate non-exocytotic transmitter efflux that induces psychomotor stimulation, addiction, altered mood, hallucinations, and psychosis, thus constituting a major component of drug neurochemical and behavioral outcomes. Efflux is under the control of transporter post-translational modifications that synergize with other regulatory events, and this review will summarize our knowledge of these processes and their role in drug mechanisms.
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Affiliation(s)
- Roxanne A Vaughan
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, United States.
| | - L Keith Henry
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, United States
| | - James D Foster
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, United States
| | - Christopher R Brown
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, United States
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8
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Paul A, Shukla D. Oligomerization of Monoamine Transporters. Subcell Biochem 2024; 104:119-137. [PMID: 38963486 DOI: 10.1007/978-3-031-58843-3_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/05/2024]
Abstract
Transporters of the monoamine transporter (MAT) family regulate the uptake of important neurotransmitters like dopamine, serotonin, and norepinephrine. The MAT family functions using the electrochemical gradient of ions across the membrane and comprises three transporters, dopamine transporter (DAT), serotonin transporter (SERT), and norepinephrine transporter (NET). MAT transporters have been observed to exist in monomeric states to higher-order oligomeric states. Structural features, allosteric modulation, and lipid environment regulate the oligomerization of MAT transporters. NET and SERT oligomerization are regulated by levels of PIP2 present in the membrane. The kink present in TM12 in the MAT family is crucial for dimer interface formation. Allosteric modulation in the dimer interface hinders dimer formation. Oligomerization also influences the transporters' function, trafficking, and regulation. This chapter will focus on recent studies on monoamine transporters and discuss the factors affecting their oligomerization and its impact on their function.
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Affiliation(s)
- Arnav Paul
- Department of Chemistry, University of Illinois Urbana-Champaign, Urbana, IL, USA
| | - Diwakar Shukla
- Department of Chemical and Biomolecular Engineering, Department of Bioengineering, Center for Biophysics and Quantitative Biology, Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
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9
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Huang T, Zhou J, Wang B, Wang X, Xiao W, Yang M, Liu Y, Wang Q, Xiang Y, Lan X. Integrated Amino Acids and Transcriptome Analysis Reveals Arginine Transporter SLC7A2 Is a Novel Regulator of Myogenic Differentiation. Int J Mol Sci 2023; 25:95. [PMID: 38203268 PMCID: PMC10778648 DOI: 10.3390/ijms25010095] [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: 10/20/2023] [Revised: 12/12/2023] [Accepted: 12/16/2023] [Indexed: 01/12/2024] Open
Abstract
Skeletal muscle differentiation is a precisely coordinated process. While many of the molecular details of myogenesis have been investigated extensively, the dynamic changes and functions of amino acids and related transporters remain unknown. In this study, we conducted a comprehensive analysis of amino acid levels during different time points of C2C12 myoblast differentiation using high-performance liquid chromatography (HPLC). Our findings revealed that the levels of most amino acids exhibited an initial increase at the onset of differentiation, reaching their peak typically on the fourth or sixth day, followed by a decline on the eighth day. Particularly, arginine and branched-chain amino acids showed a prominent increase during this period. Furthermore, we used RNA-seq analysis to show that the gene encoding the arginine transporter, Slc7a2, is significantly upregulated during differentiation. Knockdown of Slc7a2 gene expression resulted in a significant decrease in myoblast proliferation and led to a reduction in the expression levels of crucial myogenic regulatory factors, hindering the process of myoblast differentiation, fusion, and subsequent myotube formation. Lastly, we assessed the expression level of Slc7a2 during aging in humans and mice and found an upregulation of Slc7a2 expression during the aging process. These findings collectively suggest that the arginine transporter SLC7A2 plays a critical role in facilitating skeletal muscle differentiation and may hold potential as a therapeutic target for sarcopenia.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Yang Xiang
- Metabolic Control and Aging—Jiangxi Key Laboratory of Human Aging, Human Aging Research Institute (HARI), School of Life Science, Nanchang University, Nanchang 330031, China (Q.W.)
| | - Xinqiang Lan
- Metabolic Control and Aging—Jiangxi Key Laboratory of Human Aging, Human Aging Research Institute (HARI), School of Life Science, Nanchang University, Nanchang 330031, China (Q.W.)
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10
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Nguyen VT, Harris AC, Eltit JM. Structural and functional perspectives on interactions between synthetic cathinones and monoamine transporters. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2023; 99:83-124. [PMID: 38467490 DOI: 10.1016/bs.apha.2023.09.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/13/2024]
Abstract
Synthetic cathinone derivatives comprise a family of psychoactive compounds structurally related to amphetamine. Over the last decade, clandestine chemists have synthesized a consistent stream of innovative cathinone derivatives to outpace governmental regulatory restrictions. Many of these unregulated substances are produced and distributed as designer drugs. Two of the principal chemical scaffolds exploited to expand the synthetic cathinone family are methcathinone and α-pyrrolidinopentiophenone (or α-pyrrolidinovalerophenone, α-PVP). These compounds' main physiological targets are monoamine transporters, where they promote addiction by potentiating dopaminergic neurotransmission. This chapter describes techniques used to study the pharmacodynamic properties of cathinones at monoamine transporters in vitro. Biochemical techniques described include uptake inhibition and release assays in rat brain synaptosomes and in mammalian expression systems. Electrophysiological techniques include current measurements using the voltage clamp technique. We describe a Ca2+ mobilization assay wherein voltage-gated Ca2+ channels function as reporters to study the action of synthetic cathinones at monoamine transporters. We discuss results from systematic structure-activity relationship studies on simple and complex cathinones at monoamine transporters with an emphasis on identifying structural moieties that modulate potency and selectivity at these transporters. Moreover, different profiles of selectivity at monoamine transporters directly predict compounds associated with behavioral and subjective effects within animals and humans. In conclusion, clarification of the structural aspects of compounds which modulate potency and selectivity at monoamine transporters is critical to identify and predict potential addictive drugs. This knowledge may allow prompt allocation of resources toward drugs that represent the greatest threats after drugs are identified by forensic laboratories.
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Affiliation(s)
- Vy T Nguyen
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA, United States
| | - Alan C Harris
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA, United States
| | - Jose M Eltit
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA, United States.
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11
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Yang D, Zhao Z, Tajkhorshid E, Gouaux E. Structures and membrane interactions of native serotonin transporter in complexes with psychostimulants. Proc Natl Acad Sci U S A 2023; 120:e2304602120. [PMID: 37436958 PMCID: PMC10629533 DOI: 10.1073/pnas.2304602120] [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: 03/20/2023] [Accepted: 05/03/2023] [Indexed: 07/14/2023] Open
Abstract
The serotonin transporter (SERT) is a member of the SLC6 neurotransmitter transporter family that mediates serotonin reuptake at presynaptic nerve terminals. SERT is the target of both therapeutic antidepressant drugs and psychostimulant substances such as cocaine and methamphetamines, which are small molecules that perturb normal serotonergic transmission by interfering with serotonin transport. Despite decades of studies, important functional aspects of SERT such as the oligomerization state of native SERT and its interactions with potential proteins remain unresolved. Here, we develop methods to isolate SERT from porcine brain (pSERT) using a mild, nonionic detergent, utilize fluorescence-detection size-exclusion chromatography to investigate its oligomerization state and interactions with other proteins, and employ single-particle cryo-electron microscopy to elucidate the structures of pSERT in complexes with methamphetamine or cocaine, providing structural insights into psychostimulant recognition and accompanying pSERT conformations. Methamphetamine and cocaine both bind to the central site, stabilizing the transporter in an outward open conformation. We also identify densities attributable to multiple cholesterol or cholesteryl hemisuccinate (CHS) molecules, as well as to a detergent molecule bound to the pSERT allosteric site. Under our conditions of isolation, we find that pSERT is best described as a monomeric entity, isolated without interacting proteins, and is ensconced by multiple cholesterol or CHS molecules.
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Affiliation(s)
- Dongxue Yang
- Vollum Institute, Oregon Health and Science University, Portland, OR97239
| | - Zhiyu Zhao
- Department of Biochemistry, NIH Center for Macromolecular Modeling and Visualization, Beckman Institute for Advanced Science and Technology, and Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL61801
| | - Emad Tajkhorshid
- Department of Biochemistry, NIH Center for Macromolecular Modeling and Visualization, Beckman Institute for Advanced Science and Technology, and Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL61801
| | - Eric Gouaux
- Vollum Institute, Oregon Health and Science University, Portland, OR97239
- HHMI, Oregon Health and Science University, Portland, OR97239
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12
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Zhekova HR, Ramirez-Echemendía DP, Sejdiu BI, Pushkin A, Tieleman DP, Kurtz I. Coarse-grained molecular dynamics simulations of lipid-protein interactions in SLC4 proteins. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.26.546592. [PMID: 37425774 PMCID: PMC10327080 DOI: 10.1101/2023.06.26.546592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
The SLC4 family of secondary bicarbonate transporters is responsible for the transport of HCO 3 -, CO 3 2- , Cl - , Na + , K + , NH 3 and H + necessary for regulation of pH and ion homeostasis. They are widely expressed in numerous tissues throughout the body and function in different cell types with different membrane properties. Potential lipid roles in SLC4 function have been reported in experimental studies, focusing mostly on two members of the family: AE1 (Cl - /HCO 3 - exchanger) and NBCe1 (Na + -CO 3 2- cotransporter). Previous computational studies of the outward facing (OF) state of AE1 with model lipid membranes revealed enhanced protein-lipid interactions between cholesterol (CHOL) and phosphatidylinositol bisphosphate (PIP2). However, the protein-lipid interactions in other members of the family and other conformation states are still poorly understood and this precludes the detailed studies of a potential regulatory role for lipids in the SLC4 family. In this work, we performed multiple 50 µs coarse-grained molecular dynamics simulations on three members of the SLC4 family with different transport modes: AE1, NBCe1 and NDCBE (a Na + -CO 3 2- /Cl - exchanger), in model HEK293 membranes consisting of CHOL, PIP2, phosphatidylcholine (POPC), phosphatidylethanolamine (POPE), phosphatidylserine (POPS), and sphingomyelin (POSM). The recently resolved inward-facing (IF) state of AE1 was also included in the simulations. Lipid-protein contact analysis of the simulated trajectories was performed with the ProLint server, which provides a multitude of visualization tools for illustration of areas of enhanced lipid-protein contact and identification of putative lipid binding sites within the protein matrix. We observed enrichment of CHOL and PIP2 around all proteins with subtle differences in their distribution depending on the protein type and conformation state. Putative binding sites were identified for CHOL, PIP2, POPC, and POSM in the three studied proteins and their potential roles in the SLC4 transport function, conformational transition and protein dimerization were discussed. Statement of significance The SLC4 protein family is involved in critical physiological processes like pH and blood pressure regulation and maintenance of ion homeostasis. Its members can be found in various tissues. A number of studies suggest possible lipid regulation of the SLC4 function. However, the protein-lipid interactions in the SLC4 family are still poorly understood. Here we make use of long coarse-grained molecular dynamics simulations to assess the protein-lipid interactions in three SLC4 proteins with different transport modes, AE1, NBCe1, and NDCBE. We identify putative lipid binding sites for several lipid types of potential mechanistic importance, discuss them in the framework of the known experimental data and provide a necessary basis for further studies on lipid regulation of SLC4 function.
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Wu RX, Miao BB, Han FY, Niu SF, Liang YS, Liang ZB, Wang QH. Chromosome-Level Genome Assembly Provides Insights into the Evolution of the Special Morphology and Behaviour of Lepturacanthus savala. Genes (Basel) 2023; 14:1268. [PMID: 37372448 DOI: 10.3390/genes14061268] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 06/13/2023] [Accepted: 06/13/2023] [Indexed: 06/29/2023] Open
Abstract
Savalani hairtail Lepturacanthus savala is a widely distributed fish along the Indo-Western Pacific coast, and contributes substantially to trichiurid fishery resources worldwide. In this study, the first chromosome-level genome assembly of L. savala was obtained by PacBio SMRT-Seq, Illumina HiSeq, and Hi-C technologies. The final assembled L. savala genome was 790.02 Mb with contig N50 and scaffold N50 values of 19.01 Mb and 32.77 Mb, respectively. The assembled sequences were anchored to 24 chromosomes by using Hi-C data. Combined with RNA sequencing data, 23,625 protein-coding genes were predicted, of which 96.0% were successfully annotated. In total, 67 gene family expansions and 93 gene family contractions were detected in the L. savala genome. Additionally, 1825 positively selected genes were identified. Based on a comparative genomic analysis, we screened a number of candidate genes associated with the specific morphology, behaviour-related immune system, and DNA repair mechanisms in L. savala. Our results preliminarily revealed mechanisms underlying the special morphological and behavioural characteristics of L. savala from a genomic perspective. Furthermore, this study provides valuable reference data for subsequent molecular ecology studies of L. savala and whole-genome analyses of other trichiurid fishes.
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Affiliation(s)
- Ren-Xie Wu
- College of Fisheries, Guangdong Ocean University, Zhanjiang 524088, China
| | - Ben-Ben Miao
- College of Fisheries, Guangdong Ocean University, Zhanjiang 524088, China
| | - Fang-Yuan Han
- College of Fisheries, Guangdong Ocean University, Zhanjiang 524088, China
| | - Su-Fang Niu
- College of Fisheries, Guangdong Ocean University, Zhanjiang 524088, China
| | - Yan-Shan Liang
- College of Fisheries, Guangdong Ocean University, Zhanjiang 524088, China
| | - Zhen-Bang Liang
- College of Fisheries, Guangdong Ocean University, Zhanjiang 524088, China
| | - Qing-Hua Wang
- College of Fisheries, Guangdong Ocean University, Zhanjiang 524088, China
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14
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Kearney PJ, Bolden NC, Kahuno E, Conklin TL, Martin GE, Lubec G, Melikian HE. Presynaptic Gq-coupled receptors drive biphasic dopamine transporter trafficking that modulates dopamine clearance and motor function. J Biol Chem 2023; 299:102900. [PMID: 36640864 PMCID: PMC9943899 DOI: 10.1016/j.jbc.2023.102900] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Revised: 12/23/2022] [Accepted: 01/03/2023] [Indexed: 01/13/2023] Open
Abstract
Extracellular dopamine (DA) levels are constrained by the presynaptic DA transporter (DAT), a major psychostimulant target. Despite its necessity for DA neurotransmission, DAT regulation in situ is poorly understood, and it is unknown whether regulated DAT trafficking impacts dopaminergic signaling and/or behaviors. Leveraging chemogenetics and conditional gene silencing, we found that activating presynaptic Gq-coupled receptors, either hM3Dq or mGlu5, drove rapid biphasic DAT membrane trafficking in ex vivo striatal slices, with region-specific differences between ventral and dorsal striata. DAT insertion required D2 DA autoreceptors and intact retromer, whereas DAT retrieval required PKC activation and Rit2. Ex vivo voltammetric studies revealed that DAT trafficking impacts DA clearance. Furthermore, dopaminergic mGlu5 silencing elevated DAT surface expression and abolished motor learning, which was rescued by inhibiting DAT with a subthreshold CE-158 dose. We discovered that presynaptic DAT trafficking is complex, multimodal, and region specific, and for the first time, we identified cell autonomous mechanisms that govern presynaptic DAT tone. Importantly, the findings are consistent with a role for regulated DAT trafficking in DA clearance and motor function.
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Affiliation(s)
- Patrick J. Kearney
- Brudnick Neuropsychiatric Research Institute, Department of Neurobiology, UMASS Chan Medical School, Worcester, Massachusetts, USA,Morningside Graduate School of Biomedical Sciences, UMASS Chan Medical School, Worcester, Massachusetts, USA
| | - Nicholas C. Bolden
- Brudnick Neuropsychiatric Research Institute, Department of Neurobiology, UMASS Chan Medical School, Worcester, Massachusetts, USA,Morningside Graduate School of Biomedical Sciences, UMASS Chan Medical School, Worcester, Massachusetts, USA
| | - Elizabeth Kahuno
- Brudnick Neuropsychiatric Research Institute, Department of Neurobiology, UMASS Chan Medical School, Worcester, Massachusetts, USA
| | - Tucker L. Conklin
- Brudnick Neuropsychiatric Research Institute, Department of Neurobiology, UMASS Chan Medical School, Worcester, Massachusetts, USA
| | - Gilles E. Martin
- Brudnick Neuropsychiatric Research Institute, Department of Neurobiology, UMASS Chan Medical School, Worcester, Massachusetts, USA
| | - Gert Lubec
- Department of Neuroproteomics, Paracelsus Private Medical University, Salzburg, Austria
| | - Haley E. Melikian
- Brudnick Neuropsychiatric Research Institute, Department of Neurobiology, UMASS Chan Medical School, Worcester, Massachusetts, USA,For correspondence: Haley E. Melikian
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15
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Bhatt M, Gauthier-Manuel L, Lazzarin E, Zerlotti R, Ziegler C, Bazzone A, Stockner T, Bossi E. A comparative review on the well-studied GAT1 and the understudied BGT-1 in the brain. Front Physiol 2023; 14:1145973. [PMID: 37123280 PMCID: PMC10137170 DOI: 10.3389/fphys.2023.1145973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 03/30/2023] [Indexed: 05/02/2023] Open
Abstract
γ-aminobutyric acid (GABA) is the primary inhibitory neurotransmitter in the central nervous system (CNS). Its homeostasis is maintained by neuronal and glial GABA transporters (GATs). The four GATs identified in humans are GAT1 (SLC6A1), GAT2 (SLC6A13), GAT3 (SLC6A11), and betaine/GABA transporter-1 BGT-1 (SLC6A12) which are all members of the solute carrier 6 (SLC6) family of sodium-dependent transporters. While GAT1 has been investigated extensively, the other GABA transporters are less studied and their role in CNS is not clearly defined. Altered GABAergic neurotransmission is involved in different diseases, but the importance of the different transporters remained understudied and limits drug targeting. In this review, the well-studied GABA transporter GAT1 is compared with the less-studied BGT-1 with the aim to leverage the knowledge on GAT1 to shed new light on the open questions concerning BGT-1. The most recent knowledge on transporter structure, functions, expression, and localization is discussed along with their specific role as drug targets for neurological and neurodegenerative disorders. We review and discuss data on the binding sites for Na+, Cl-, substrates, and inhibitors by building on the recent cryo-EM structure of GAT1 to highlight specific molecular determinants of transporter functions. The role of the two proteins in GABA homeostasis is investigated by looking at the transport coupling mechanism, as well as structural and kinetic transport models. Furthermore, we review information on selective inhibitors together with the pharmacophore hypothesis of transporter substrates.
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Affiliation(s)
- Manan Bhatt
- Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
- Centre for Neuroscience—University of Insubria, Varese, Italy
| | - Laure Gauthier-Manuel
- Department of Biophysics II/Structural Biology, University of Regensburg, Regensburg, Germany
| | - Erika Lazzarin
- Center for Physiology and Pharmacology, Institute of Pharmacology, Medical University of Vienna, Waehringerstr, Vienna
| | - Rocco Zerlotti
- Department of Biophysics II/Structural Biology, University of Regensburg, Regensburg, Germany
- Nanion Technologies GmbH, Munich, Germany
| | - Christine Ziegler
- Department of Biophysics II/Structural Biology, University of Regensburg, Regensburg, Germany
| | | | - Thomas Stockner
- Center for Physiology and Pharmacology, Institute of Pharmacology, Medical University of Vienna, Waehringerstr, Vienna
- *Correspondence: Thomas Stockner, ; Elena Bossi,
| | - Elena Bossi
- Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
- Centre for Neuroscience—University of Insubria, Varese, Italy
- *Correspondence: Thomas Stockner, ; Elena Bossi,
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16
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Nepal B, Das S, Reith ME, Kortagere S. Overview of the structure and function of the dopamine transporter and its protein interactions. Front Physiol 2023; 14:1150355. [PMID: 36935752 PMCID: PMC10020207 DOI: 10.3389/fphys.2023.1150355] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 02/21/2023] [Indexed: 03/06/2023] Open
Abstract
The dopamine transporter (DAT) plays an integral role in dopamine neurotransmission through the clearance of dopamine from the extracellular space. Dysregulation of DAT is central to the pathophysiology of numerous neuropsychiatric disorders and as such is an attractive therapeutic target. DAT belongs to the solute carrier family 6 (SLC6) class of Na+/Cl- dependent transporters that move various cargo into neurons against their concentration gradient. This review focuses on DAT (SCL6A3 protein) while extending the narrative to the closely related transporters for serotonin and norepinephrine where needed for comparison or functional relevance. Cloning and site-directed mutagenesis experiments provided early structural knowledge of DAT but our contemporary understanding was achieved through a combination of crystallization of the related bacterial transporter LeuT, homology modeling, and subsequently the crystallization of drosophila DAT. These seminal findings enabled a better understanding of the conformational states involved in the transport of substrate, subsequently aiding state-specific drug design. Post-translational modifications to DAT such as phosphorylation, palmitoylation, ubiquitination also influence the plasma membrane localization and kinetics. Substrates and drugs can interact with multiple sites within DAT including the primary S1 and S2 sites involved in dopamine binding and novel allosteric sites. Major research has centered around the question what determines the substrate and inhibitor selectivity of DAT in comparison to serotonin and norepinephrine transporters. DAT has been implicated in many neurological disorders and may play a role in the pathology of HIV and Parkinson's disease via direct physical interaction with HIV-1 Tat and α-synuclein proteins respectively.
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Affiliation(s)
- Binod Nepal
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, United States
| | - Sanjay Das
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, United States
| | - Maarten E. Reith
- Department of Psychiatry, New York University School of Medicine, New York City, NY, United States
| | - Sandhya Kortagere
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, United States
- *Correspondence: Sandhya Kortagere,
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17
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Cross-Linking and Functional Analyses for Dimerization of a Cysteine Mutant of Glycine Transporter 1. Int J Mol Sci 2022; 23:ijms232416157. [PMID: 36555800 PMCID: PMC9781295 DOI: 10.3390/ijms232416157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Revised: 12/10/2022] [Accepted: 12/15/2022] [Indexed: 12/23/2022] Open
Abstract
Glycine transporter 1 (GlyT1) is responsible for the reuptake of glycine, which regulates glutamate signaling as a co-agonist with N-methyl-D-aspartic acid (NMDA) receptors in the excitatory synapse and has been proposed to be a potential target in the development of therapies for a broad range of disorders of the central nervous system. Despite significant progress in characterizing structure and transport mechanism of the transporter, the regulation of transport function through oligomerization remains to be understood. In the present work, association of two forms of GlyT1 into dimers and higher order oligomers was detected by coimmunoprecipitation. To investigate functional properties of dimers of a GlyT1 cysteine mutant L288C, we performed oxidative cross-linking of the positioned cysteine residues in extracellular loop 3 (EL3) near the extracellular end of TM6. By analyzing the effect of copper phenanthroline (CuP)-induced dimerization on transport function, cross-linking of L288C was found to inhibit transport activity. In addition, an intramolecular ion pair Lys286-Glu289 was revealed to be critical for stabilizing EL3 in a conformation that modulates CuP-induced dimerization and transport function of the GlyT1 L288C mutant. Furthermore, the influence of transporter conformation on GlyT1 L288C dimerization was investigated. The substrate glycine, in the presence of both Na+ and Cl-, significantly reduced oxidative cross-linking, suggesting a large-scale rotation of the bundle domain during substrate transport impairs interfacial interactions between L288C protomers. The present study provides new insights into structural and functional elements regulating GlyT1 transport activity through its dimerization or oligomerization.
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18
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Luethi D, Maier J, Rudin D, Szöllősi D, Angenoorth TJF, Stankovic S, Schittmayer M, Burger I, Yang JW, Jaentsch K, Holy M, Das AK, Brameshuber M, Camacho-Hernandez GA, Casiraghi A, Newman AH, Kudlacek O, Birner-Gruenberger R, Stockner T, Schütz GJ, Sitte HH. Phosphatidylinositol 4,5-bisphosphate (PIP 2) facilitates norepinephrine transporter dimerization and modulates substrate efflux. Commun Biol 2022; 5:1259. [PMID: 36396757 PMCID: PMC9672106 DOI: 10.1038/s42003-022-04210-1] [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: 05/03/2022] [Accepted: 11/01/2022] [Indexed: 11/19/2022] Open
Abstract
The plasmalemmal norepinephrine transporter (NET) regulates cardiovascular sympathetic activity by clearing extracellular norepinephrine in the synaptic cleft. Here, we investigate the subunit stoichiometry and function of NET using single-molecule fluorescence microscopy and flux assays. In particular, we show the effect of phosphatidylinositol 4,5-bisphosphate (PIP2) on NET oligomerization and efflux. NET forms monomers (~60%) and dimers (~40%) at the plasma membrane. PIP2 depletion results in a decrease in the average oligomeric state and decreases NET-mediated substrate efflux while not affecting substrate uptake. Mutation of the putative PIP2 binding residues R121, K334, and R440 to alanines does not affect NET dimerization but results in decreased substrate efflux that is not altered upon PIP2 depletion; this indicates that PIP2 interactions with these residues affect NET-mediated efflux. A dysregulation of norepinephrine and PIP2 signaling have both been implicated in neuropsychiatric and cardiovascular diseases. This study provides evidence that PIP2 directly regulates NET organization and function.
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Affiliation(s)
- Dino Luethi
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringer Strasse 13A, 1090, Vienna, Austria
- Institute of Applied Physics, TU Wien, Lehargasse 6, 1060, Vienna, Austria
| | - Julian Maier
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringer Strasse 13A, 1090, Vienna, Austria
| | - Deborah Rudin
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringer Strasse 13A, 1090, Vienna, Austria
| | - Dániel Szöllősi
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringer Strasse 13A, 1090, Vienna, Austria
| | - Thomas J F Angenoorth
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringer Strasse 13A, 1090, Vienna, Austria
| | - Stevan Stankovic
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringer Strasse 13A, 1090, Vienna, Austria
| | - Matthias Schittmayer
- Institute of Chemical Technologies and Analytics, TU Wien, Getreidemarkt 9, 1060, Vienna, Austria
| | - Isabella Burger
- Institute of Chemical Technologies and Analytics, TU Wien, Getreidemarkt 9, 1060, Vienna, Austria
| | - Jae-Won Yang
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringer Strasse 13A, 1090, Vienna, Austria
| | - Kathrin Jaentsch
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringer Strasse 13A, 1090, Vienna, Austria
| | - Marion Holy
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringer Strasse 13A, 1090, Vienna, Austria
| | - Anand Kant Das
- Institute of Applied Physics, TU Wien, Lehargasse 6, 1060, Vienna, Austria
- Physics Program, New York University Abu Dhabi, Saadiyat Island, 129188, Abu Dhabi, United Arab Emirates
| | - Mario Brameshuber
- Institute of Applied Physics, TU Wien, Lehargasse 6, 1060, Vienna, Austria
| | - Gisela Andrea Camacho-Hernandez
- Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse - Intramural Research Program, Baltimore, MD, 21224, USA
| | - Andrea Casiraghi
- Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse - Intramural Research Program, Baltimore, MD, 21224, USA
- Department of Pharmaceutical Sciences, University of Milan, Via Luigi Mangiagalli 25, 20133, Milan, Italy
| | - Amy Hauck Newman
- Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse - Intramural Research Program, Baltimore, MD, 21224, USA
| | - Oliver Kudlacek
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringer Strasse 13A, 1090, Vienna, Austria
| | - Ruth Birner-Gruenberger
- Institute of Chemical Technologies and Analytics, TU Wien, Getreidemarkt 9, 1060, Vienna, Austria
- Diagnostic and Research Institute of Pathology, Medical University of Graz, Neue Stiftingtalstrasse 6, 8010, Graz, Austria
| | - Thomas Stockner
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringer Strasse 13A, 1090, Vienna, Austria
| | - Gerhard J Schütz
- Institute of Applied Physics, TU Wien, Lehargasse 6, 1060, Vienna, Austria.
| | - Harald H Sitte
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringer Strasse 13A, 1090, Vienna, Austria.
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Determining Ligand and Ion-Induced Conformational Changes in Serotonin Transporter with Its Fluorescent Substrates. Int J Mol Sci 2022; 23:ijms231810919. [PMID: 36142837 PMCID: PMC9503009 DOI: 10.3390/ijms231810919] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 09/14/2022] [Accepted: 09/16/2022] [Indexed: 01/22/2023] Open
Abstract
Conformational changes are fundamental events in the transport mechanism. The serotonin transporter (SERT) catalyzes reuptake of the neurotransmitter serotonin after its release by serotonergic neurons and is the molecular target for antidepressant drugs and psychostimulants. Despite significant progress in characterizing the structure-function relationship of SERT, its conformational mechanism has not been fully understood. We present here a cell-based method for determining conformational changes in SERT with its fluorescent substrates by fluorescence imaging analysis. This method fluorometrically measures accessibility of strategically positioned cysteine residues in the substrate permeation pathway to calculate the rate constants of reactivity with MTS reagents in live or permeabilized cells. We validated this method by investigating ligand and ion-induced conformational changes in both the extracellular and cytoplasmic pathways of SERT. Furthermore, we applied this method for examining the influence of Cl- binding and vilazodone inhibition on SERT conformation. Our results showed that Cl- ion, in the presence of Na+, facilitates the conformational conversion from outward to inward open states, and that vilazodone binding stabilizes SERT in an outward open and inward-closed conformation. The present work provided insights into the conformational mechanism of SERT and also indicated that the cell-based fluorometric method is robust, straightforward to perform, and potentially applicable to any monoamine transporters in exploring the transport mechanism and mechanism of action of therapeutic agents for the treatment of several psychiatric disorders.
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Danbolt NC, López-Corcuera B, Zhou Y. Reconstitution of GABA, Glycine and Glutamate Transporters. Neurochem Res 2022; 47:85-110. [PMID: 33905037 PMCID: PMC8763731 DOI: 10.1007/s11064-021-03331-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 04/13/2021] [Accepted: 04/15/2021] [Indexed: 10/25/2022]
Abstract
In contrast to water soluble enzymes which can be purified and studied while in solution, studies of solute carrier (transporter) proteins require both that the protein of interest is situated in a phospholipid membrane and that this membrane forms a closed compartment. An additional challenge to the study of transporter proteins has been that the transport depends on the transmembrane electrochemical gradients. Baruch I. Kanner understood this early on and first developed techniques for studying plasma membrane vesicles. This advanced the field in that the experimenter could control the electrochemical gradients. Kanner, however, did not stop there, but started to solubilize the membranes so that the transporter proteins were taken out of their natural environment. In order to study them, Kanner then had to find a way to reconstitute them (reinsert them into phospholipid membranes). The scope of the present review is both to describe the reconstitution method in full detail as that has never been done, and also to reveal the scientific impact that this method has had. Kanner's later work is not reviewed here although that also deserves a review because it too has had a huge impact.
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Affiliation(s)
- Niels Christian Danbolt
- Neurotransporter Group, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, 0317, Oslo, Norway.
| | - Beatriz López-Corcuera
- Departamento de Biología Molecular, Universidad Autónoma de Madrid, Madrid, Spain
- Centro de Biología Molecular "Severo Ochoa" Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Madrid, Spain
- IdiPAZ, Hospital Universitario La Paz, Madrid, Spain
| | - Yun Zhou
- Neurotransporter Group, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, 0317, Oslo, Norway
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Sahai M, Opacka-Juffry J. Molecular mechanisms of action of stimulant novel psychoactive substances that target the high-affinity transporter for dopamine. Neuronal Signal 2021; 5:NS20210006. [PMID: 34888062 PMCID: PMC8630395 DOI: 10.1042/ns20210006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 10/28/2021] [Accepted: 11/01/2021] [Indexed: 11/17/2022] Open
Abstract
Drug misuse is a significant social and public health problem worldwide. Misused substances exert their neurobehavioural effects through changing neural signalling within the brain, many of them leading to substance dependence and addiction in the longer term. Among drugs with addictive liability, there are illicit classical stimulants such as cocaine and amphetamine, and their more recently available counterparts known as novel psychoactive substances (NPS). Stimulants normally increase dopamine availability in the brain, including the pathway implicated in reward-related behaviour. This pattern is observed in both animal and human brain. The main biological target of stimulants, both classical and NPS, is the dopamine transporter (DAT) implicated in the dopamine-enhancing effects of these drugs. This article aims at reviewing research on the molecular mechanisms underpinning the interactions between stimulant NPS, such as benzofurans, cathinones or piperidine derivatives and DAT, to achieve a greater understanding of the core phenomena that decide about the addictive potential of stimulant NPS. As the methodology is essential in the process of experimental research in this area, we review the applications of in vitro, in vivo and in silico approaches. The latter, including molecular dynamics, attracts the focus of the present review as the method of choice in molecular and atomistic investigations of the mechanisms of addiction of stimulant NPS. Research of this kind is of interest to not only scientists but also health professionals as updated knowledge of NPS, their modes of action and health risks, is needed to tackle the challenges posed by NPS misuse.
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Affiliation(s)
- Michelle A. Sahai
- School of Life and Health Sciences, University of Roehampton, London SW15 4JD, U.K
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22
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ZnT1 is a neuronal Zn 2+/Ca 2+ exchanger. Cell Calcium 2021; 101:102505. [PMID: 34871934 DOI: 10.1016/j.ceca.2021.102505] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Revised: 10/31/2021] [Accepted: 11/22/2021] [Indexed: 01/22/2023]
Abstract
Zinc transporter 1 (ZnT1; SLC30A1) is present in the neuronal plasma membrane, critically modulating NMDA receptor function and Zn2+ neurotoxicity. The mechanism mediating Zn2+ transport by ZnT1, however, has remained elusive. Here, we investigated ZnT1-dependent Zn2+ transport by measuring intracellular changes of this ion using the fluorescent indicator FluoZin-3. In primary mouse cortical neurons, which express ZnT1, transient addition of extracellular Zn2+ triggered a rise in cytosolic Zn2+, followed by its removal. Knockdown of ZnT1 by adeno associated viral (AAV)-short hairpin RNA (shZnT1) markedly increased rates of Zn2+ rise, and decreased rates of its removal, suggesting that ZnT1 is a primary route for Zn2+ efflux in neurons. Although Zn2+ transport by other members of the SLC30A family is dependent on pH gradients across cellular membranes, altered H+ gradients were not coupled to ZnT1-dependent transport. Removal of cytoplasmic Zn2+, against a large inward gradient during the initial loading phase, suggests that Zn2+ efflux requires a large driving force. We therefore asked if Ca2+ gradients across the membrane can facilitate Zn2+ efflux. Elimination of extracellular Ca2+ abolished Zn2+ efflux, while increased extracellular Ca2+ levels enhanced Zn2+ efflux. Intracellular Ca2+ rises, measured in GCaMP6 expressing neurons, closely paralleled cytoplasmic Zn2+ removal. Taken together, these results strongly suggest that ZnT1 functions as a Zn2+/Ca2+ exchanger, thereby regulating the transport of two ions of fundamental importance in neuronal signaling.
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Miller DR, Bu AM, Gopinath A, Martinez LR, Khoshbouei H. Methamphetamine dysregulation of the central nervous system and peripheral immunity. J Pharmacol Exp Ther 2021; 379:372-385. [PMID: 34535563 DOI: 10.1124/jpet.121.000767] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 09/16/2021] [Indexed: 11/22/2022] Open
Abstract
Methamphetamine (METH) is a potent psychostimulant that increases extracellular monoamines such as dopamine and norepinephrine and affects multiple tissue and cell types. The reinforcing properties of METH underlie its significant abuse potential and dysregulation of peripheral immunity and central nervous system functions. Together, the constellation of METH's effects on cellular targets and regulatory processes have shown to lead to immune suppression and neurodegeneration in METH addicts and animal models of METH exposure. Here we extensively review many of the cell types and mechanisms of METH-induced dysregulation of the central nervous system and peripheral immune system. Significance Statement Emerging research has begun to show that methamphetamine not only regulates dopaminergic neuronal activity, it also affects non-neuronal brain cells, such as microglia and astrocytes as well immunological cells of the periphery. The bi-directional communication between dopaminergic neurons in the CNS and peripheral immune cells becomes dysregulated by a constellation of dysfunctional neuronal and cell types revealing multiple targets that must be considered at the interface between basic and clinical neuroscience.
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Affiliation(s)
| | | | - Adithya Gopinath
- Department of Neuroscience, University of Florida, United States
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24
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Castagna M, Cinquetti R, Verri T, Vacca F, Giovanola M, Barca A, Romanazzi T, Roseti C, Galli A, Bossi E. The Lepidopteran KAAT1 and CAATCH1: Orthologs to Understand Structure-Function Relationships in Mammalian SLC6 Transporters. Neurochem Res 2021; 47:111-126. [PMID: 34304372 PMCID: PMC8310414 DOI: 10.1007/s11064-021-03410-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Revised: 04/18/2021] [Accepted: 07/20/2021] [Indexed: 11/16/2022]
Abstract
To the SLC6 family belong 20 human transporters that utilize the sodium electrochemical gradient to move biogenic amines, osmolytes, amino acids and related compounds into cells. They are classified into two functional groups, the Neurotransmitter transporters (NTT) and Nutrient amino acid transporters (NAT). Here we summarize how since their first cloning in 1998, the insect (Lepidopteran) Orthologs of the SLC6 family transporters have represented very important tools for investigating functional–structural relationships, mechanism of transport, ion and pH dependence and substate interaction of the mammalian (and human) counterparts.
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Affiliation(s)
- Michela Castagna
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, Via Trentacoste 2, 20134, Milan, Italy
| | - Raffaella Cinquetti
- Laboratory of Cellular and Molecular Physiology, Department of Biotechnology and Life Sciences, University of Insubria, via Dunant 3, 21100, Varese, Italy
| | - Tiziano Verri
- Laboratory of Applied Physiology, Department of Biological and Environmental Sciences and Technologies, University of Salento, Via Provinciale Lecce-Monteroni, 73100, Lecce, Italy
| | - Francesca Vacca
- Laboratory of Cellular and Molecular Physiology, Department of Biotechnology and Life Sciences, University of Insubria, via Dunant 3, 21100, Varese, Italy
| | - Matteo Giovanola
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, Via Trentacoste 2, 20134, Milan, Italy
| | - Amilcare Barca
- Laboratory of Applied Physiology, Department of Biological and Environmental Sciences and Technologies, University of Salento, Via Provinciale Lecce-Monteroni, 73100, Lecce, Italy
| | - Tiziana Romanazzi
- Laboratory of Cellular and Molecular Physiology, Department of Biotechnology and Life Sciences, University of Insubria, via Dunant 3, 21100, Varese, Italy
| | - Cristina Roseti
- Laboratory of Cellular and Molecular Physiology, Department of Biotechnology and Life Sciences, University of Insubria, via Dunant 3, 21100, Varese, Italy.,Research Centre for Neuroscience, University of Insubria, Varese, Italy
| | - Alessandra Galli
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, Via Trentacoste 2, 20134, Milan, Italy
| | - Elena Bossi
- Laboratory of Cellular and Molecular Physiology, Department of Biotechnology and Life Sciences, University of Insubria, via Dunant 3, 21100, Varese, Italy. .,Research Centre for Neuroscience, University of Insubria, Varese, Italy.
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25
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Gether U, Sitte HH. It takes two-or more-to tango: Revisiting the role of dopamine transporter oligomerization. J Biol Chem 2021; 296:100629. [PMID: 34237901 PMCID: PMC8100069 DOI: 10.1016/j.jbc.2021.100629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The dopamine transporter utilizes the transmembrane sodium gradient to mediate reuptake of dopamine from the extracellular space. The dopamine transporter can form dimers and possibly also higher order structures in the plasma membrane, and this oligomerization has been implicated in both trafficking and transport. However, we still do not fully understand its biological importance. A study by Sorkina et al. now describes a series of small molecules that link transporter conformation to oligomerization and endocytosis, providing an interesting step forward in an intricate dance.
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Affiliation(s)
- Ulrik Gether
- Department of Neuroscience, Faculty of Health and Medical Sciences, Maersk Tower 7.5, University of Copenhagen, Copenhagen, Denmark.
| | - Harald H Sitte
- Center for Physiology and Pharmacology, Institute of Pharmacology, Medical University Vienna, Vienna, Austria
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26
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Dynamic control of the dopamine transporter in neurotransmission and homeostasis. NPJ Parkinsons Dis 2021; 7:22. [PMID: 33674612 PMCID: PMC7935902 DOI: 10.1038/s41531-021-00161-2] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 01/08/2021] [Indexed: 01/31/2023] Open
Abstract
The dopamine transporter (DAT) transports extracellular dopamine into the intracellular space contributing to the regulation of dopamine neurotransmission. A reduction of DAT density is implicated in Parkinson's disease (PD) by neuroimaging; dopamine turnover is dopamine turnover is elevated in early symptomatic PD and in presymptomatic individuals with monogenic mutations causal for parkinsonism. As an integral plasma membrane protein, DAT surface expression is dynamically regulated through endocytic trafficking, enabling flexible control of dopamine signaling in time and space, which in turn critically modulates movement, motivation and learning behavior. Yet the cellular machinery and functional implications of DAT trafficking remain enigmatic. In this review we summarize mechanisms governing DAT trafficking under normal physiological conditions and discuss how PD-linked mutations may disturb DAT homeostasis. We highlight the complexity of DAT trafficking and reveal DAT dysregulation as a common theme in genetic models of parkinsonism.
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27
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Julku UH, Jäntti M, Svarcbahs R, Myöhänen TT. Prolyl Oligopeptidase Regulates Dopamine Transporter Oligomerization and Phosphorylation in a PKC- and ERK-Independent Manner. Int J Mol Sci 2021; 22:1777. [PMID: 33579026 PMCID: PMC7916783 DOI: 10.3390/ijms22041777] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 02/04/2021] [Accepted: 02/05/2021] [Indexed: 12/18/2022] Open
Abstract
Prolyl oligopeptidase (PREP) is a serine protease that binds to alpha-synuclein (aSyn) and induces its aggregation. PREP inhibitors have been shown to have beneficial effects in Parkinson's disease models by enhancing the clearance of aSyn aggregates and modulating striatal dopamine. Additionally, we have shown that PREP regulates phosphorylation and internalization of dopamine transporter (DAT) in mice. In this study, we clarified the mechanism behind this by using HEK-293 and PREP knock-out HEK-293 cells with DAT transfection. We tested the effects of PREP, PREP inhibition, and alpha-synuclein on PREP-related DAT regulation by using Western blot analysis and a dopamine uptake assay, and characterized the impact of PREP on protein kinase C (PKC) and extracellular signal-regulated kinase (ERK) by using PKC assay and Western blot, respectively, as these kinases regulate DAT phosphorylation. Our results confirmed our previous findings that a lack of PREP can increase phosphorylation and internalization of DAT and decrease uptake of dopamine. PREP inhibition had a variable impact on phosphorylation of ERK dependent on the metabolic state of cells, but did not have an effect on phosphorylation or function of DAT. PREP modifications did not affect PKC activity either. Additionally, a lack of PREP elevated a DAT oligomerization that is associated with intracellular trafficking of DAT. Our results suggest that PREP-mediated phosphorylation, oligomerization, and internalization of DAT is not dependent on PKC or ERK.
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Affiliation(s)
- Ulrika H. Julku
- Division of Pharmacology and Pharmacotherapy/Drug Research Program, Faculty of Pharmacy, University of Helsinki, Viikinkaari 5E (P.O. Box 56), FI-00014 Helsinki, Finland; (U.H.J.); (M.J.); (R.S.)
| | - Maria Jäntti
- Division of Pharmacology and Pharmacotherapy/Drug Research Program, Faculty of Pharmacy, University of Helsinki, Viikinkaari 5E (P.O. Box 56), FI-00014 Helsinki, Finland; (U.H.J.); (M.J.); (R.S.)
| | - Reinis Svarcbahs
- Division of Pharmacology and Pharmacotherapy/Drug Research Program, Faculty of Pharmacy, University of Helsinki, Viikinkaari 5E (P.O. Box 56), FI-00014 Helsinki, Finland; (U.H.J.); (M.J.); (R.S.)
| | - Timo T. Myöhänen
- Division of Pharmacology and Pharmacotherapy/Drug Research Program, Faculty of Pharmacy, University of Helsinki, Viikinkaari 5E (P.O. Box 56), FI-00014 Helsinki, Finland; (U.H.J.); (M.J.); (R.S.)
- Integrative Physiology and Pharmacology Unit/Institute of Biomedicine, Faculty of Medicine, University of Turku, FI-20520 Turku, Finland
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28
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Jayaraman K, Das AK, Luethi D, Szöllősi D, Schütz GJ, Reith MEA, Sitte HH, Stockner T. SLC6 transporter oligomerization. J Neurochem 2020; 157:919-929. [PMID: 32767560 PMCID: PMC8247324 DOI: 10.1111/jnc.15145] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 07/31/2020] [Accepted: 07/31/2020] [Indexed: 12/18/2022]
Abstract
Transporters of the solute carrier 6 (SLC6) family mediate the reuptake of neurotransmitters such as dopamine, norepinephrine, serotonin, GABA, and glycine. SLC6 family members are 12 transmembrane helix‐spanning proteins that operate using the transmembrane sodium gradient for transport. These transporters assume various quaternary arrangements ranging from monomers to complex stoichiometries with multiple subunits. Dopamine and serotonin transporter oligomerization has been implicated in trafficking of newly formed proteins from the endoplasmic reticulum to the plasma membrane with a pre‐fixed assembly. Once at the plasma membrane, oligomers are kept fixed in their quaternary assembly by interaction with phosphoinositides. While it remains unclear how oligomer formation precisely affects physiological transporter function, it has been shown that oligomerization supports the activity of release‐type psychostimulants. Most recently, single molecule microscopy experiments unveiled that the stoichiometry differs between individual members of the SLC6 family. The present overview summarizes our understanding of the influence of plasma membrane constituents on transporter oligomerization, describes the known interfaces between protomers and discusses open questions. ![]()
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Affiliation(s)
- Kumaresan Jayaraman
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Anand K Das
- Institute of Applied Physics, Vienna University of Technology, Vienna, Austria
| | - Dino Luethi
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria.,Institute of Applied Physics, Vienna University of Technology, Vienna, Austria
| | - Dániel Szöllősi
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Gerhard J Schütz
- Institute of Applied Physics, Vienna University of Technology, Vienna, Austria
| | - Maarten E A Reith
- Department of Psychiatry, New York University School of Medicine, New York City, NY, USA
| | - Harald H Sitte
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Thomas Stockner
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
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