2024
Identification of the potassium-binding site in serotonin transporter
Hellsberg E, Boytsov D, Chen Q, Niello M, Freissmuth M, Rudnick G, Zhang Y, Sandtner W, Forrest L. Identification of the potassium-binding site in serotonin transporter. Proceedings Of The National Academy Of Sciences Of The United States Of America 2024, 121: e2319384121. PMID: 38652746, PMCID: PMC11067047, DOI: 10.1073/pnas.2319384121.Peer-Reviewed Original ResearchConceptsSerotonin transporterSite-directed mutagenesis of residuesMutagenesis of residuesSite-directed mutagenesisHeterologous expression systemStudy of vesiclesNa2 siteClearance of serotoninPatch-clamp recordingsExpression systemBinding residuesSequential bindingMolecular dynamics simulationsBinding sitesPotassium binding siteSubstrate accumulationClamp recordingsVesiclesResiduesTurnover rateBindingStructural studiesChemical gradientsBinding configurationsSynaptic cleft
2018
Structural elements required for coupling ion and substrate transport in the neurotransmitter transporter homolog LeuT
Zhang YW, Tavoulari S, Sinning S, Aleksandrova AA, Forrest LR, Rudnick G. Structural elements required for coupling ion and substrate transport in the neurotransmitter transporter homolog LeuT. Proceedings Of The National Academy Of Sciences Of The United States Of America 2018, 115: e8854-e8862. PMID: 30181291, PMCID: PMC6156673, DOI: 10.1073/pnas.1716870115.Peer-Reviewed Original ResearchConceptsTransporter domainConformational changesOpen stateSodium symporter familyIon-substrate couplingTransmembrane ion gradientsSymporter familyNSS transportersSubstrate bindingLeuTIntracellular substratesCysteine accessibilitySubstrate transportAccessibility of substrateTyrosine residuesConformational responseNa2 siteUncoupled movementIon gradientsExtracellular pathwaysMechanistic componentsTransportersProteinTransport of ionsBinding
2015
Two Na+ Sites Control Conformational Change in a Neurotransmitter Transporter Homolog*
Tavoulari S, Margheritis E, Nagarajan A, DeWitt DC, Zhang YW, Rosado E, Ravera S, Rhoades E, Forrest LR, Rudnick G. Two Na+ Sites Control Conformational Change in a Neurotransmitter Transporter Homolog*. Journal Of Biological Chemistry 2015, 291: 1456-1471. PMID: 26582198, PMCID: PMC4714228, DOI: 10.1074/jbc.m115.692012.Peer-Reviewed Original ResearchMeSH KeywordsAmino Acid SubstitutionAmino Acid Transport SystemsAquatic OrganismsBacterial ProteinsBinding SitesCysteineGram-Negative BacteriaLigandsLiposomesModels, MolecularMolecular Dynamics SimulationMutagenesis, Site-DirectedMutationPlasma Membrane Neurotransmitter Transport ProteinsProtein ConformationProtein FoldingProtein StabilityProteolipidsRecombinant ProteinsSodiumConceptsConformational changesTransmembrane helix 1Open conformational stateDependent conformational changesTransporter homologExtracellular gateProkaryotic homologCytoplasmic pathwayHelix 1Interaction networksIntermediary interactionsBiophysical assaysNeurotransmitter transportersSubstrate pathwayNa2 siteConformational statesHelix motionsLeuTDirect interactionDependent closureHomologMutantsDistinct stepsResiduesComputational analysis
2007
Interaction between lysine 102 and aspartate 338 in the insect amino acid cotransporter KAAT1
Castagna M, Soragna A, Mari S, Santacroce M, Betté S, Mandela P, Rudnick G, Peres A, Sacchi V. Interaction between lysine 102 and aspartate 338 in the insect amino acid cotransporter KAAT1. American Journal Of Physiology - Cell Physiology 2007, 293: c1286-c1295. PMID: 17626242, DOI: 10.1152/ajpcell.00190.2007.Peer-Reviewed Original ResearchMeSH KeywordsAmino Acid SequenceAmino Acid SubstitutionAmino Acid Transport Systems, NeutralAnimalsAspartic AcidBinding SitesBiological TransportCross-Linking ReagentsCysteineDithiothreitolFemaleInsect ProteinsKineticsLepidopteraLysineModels, MolecularMolecular Sequence DataOocytesPhenanthrolinesPotassiumProtein Structure, TertiarySequence Homology, Amino AcidSodiumTryptophanXenopus laevisConceptsSingle cysteine mutantsNeutral amino acid transporterSite-directed mutagenesisAmino acid transportersTransport-associated currentNSS transportersDouble mutantXenopus laevis oocytesCysteine mutantsWild typeDependent transportLysine 102MutantsSuper familyAcid transportersPermeation pathwayAmino acidsDisulfide bondsLaevis oocytesFunctional evidenceAsp338Leucine uptakeKAAT1Spatial organizationResidues
2001
A Lithium-induced Conformational Change in Serotonin Transporter Alters Cocaine Binding, Ion Conductance, and Reactivity of Cys-109*
Ni Y, Chen J, Androutsellis-Theotokis A, Huang C, Moczydlowski E, Rudnick G. A Lithium-induced Conformational Change in Serotonin Transporter Alters Cocaine Binding, Ion Conductance, and Reactivity of Cys-109*. Journal Of Biological Chemistry 2001, 276: 30942-30947. PMID: 11408487, DOI: 10.1074/jbc.m104653200.Peer-Reviewed Original Research
2000
Functional Role of Critical Stripe Residues in Transmembrane Span 7 of the Serotonin Transporter EFFECTS OF Na+, Li+, AND METHANETHIOSULFONATE REAGENTS*
Kamdar G, Penado K, Rudnick G, Stephan M. Functional Role of Critical Stripe Residues in Transmembrane Span 7 of the Serotonin Transporter EFFECTS OF Na+, Li+, AND METHANETHIOSULFONATE REAGENTS*. Journal Of Biological Chemistry 2000, 276: 4038-4045. PMID: 11058600, DOI: 10.1074/jbc.m008483200.Peer-Reviewed Original ResearchConceptsCys-109Methanethiosulfonate reagentsWater-filled poresNative cysteine residuesCysteine-containing mutantsExtracellular loop 1Close-contact regionThree-dimensional structureCysteine residuesTranslocation mechanismControl mutantsAlpha-helixMTSEA-biotinResidue positionsCysteine substitutionsLoop 1Conformational changesMTS reagentsFunctional roleMutantsIon bindingResiduesTransportersIon dependenceSerotonin transporterPermeation and gating residues in serotonin transporter
Chen J, Rudnick G. Permeation and gating residues in serotonin transporter. Proceedings Of The National Academy Of Sciences Of The United States Of America 2000, 97: 1044-1049. PMID: 10655481, PMCID: PMC15515, DOI: 10.1073/pnas.97.3.1044.Peer-Reviewed Original ResearchMeSH KeywordsAllosteric RegulationAmino Acid SubstitutionCarrier ProteinsChloridesCocaineHumansHydrogenIon Channel GatingIon TransportIsoleucineMembrane GlycoproteinsMembrane Transport ProteinsMesylatesMutagenesis, Site-DirectedNerve Tissue ProteinsNorepinephrine Plasma Membrane Transport ProteinsOxidation-ReductionPotassiumProtein BindingProtein ConformationProtein Structure, TertiaryRecombinant Fusion ProteinsReducing AgentsSerotoninSerotonin Plasma Membrane Transport ProteinsSodiumSulfhydryl CompoundsSymportersConceptsSubstrate permeation pathway
1997
External Cysteine Residues in the Serotonin Transporter †
Chen J, Liu-Chen S, Rudnick G. External Cysteine Residues in the Serotonin Transporter †. Biochemistry 1997, 36: 1479-1486. PMID: 9063896, DOI: 10.1021/bi962256g.Peer-Reviewed Original ResearchConceptsTransport activityMTS reagentsCysteine residuesWild typeWild-type transporterSecond external loopTransient expression systemSurface expressionRat serotonin transporterExternal cysteine residuesHydropathy analysisMutant transportersType transporterDouble mutantExpression systemMethanethiosulfonate reagentsLigand bindingSerotonin transporterMutantsExtracellular loopHeLa cellsDisulfide bondsPartial activityTransportersSerine
1996
Ion Coupling Stoichiometry for the Norepinephrine Transporter in Membrane Vesicles from Stably Transfected Cells (∗)
Gu H, Wall S, Rudnick G. Ion Coupling Stoichiometry for the Norepinephrine Transporter in Membrane Vesicles from Stably Transfected Cells (∗). Journal Of Biological Chemistry 1996, 271: 6911-6916. PMID: 8636118, DOI: 10.1074/jbc.271.12.6911.Peer-Reviewed Original ResearchConceptsMembrane vesiclesTransmembrane ion gradientsLLC-PK1 cellsMajor substrateTransport substratesTransfected CellsStably Transfected CellsIon gradientsCoupling stoichiometryNet positive chargeDA accumulationVesiclesSubstrate moleculesTransportersNorepinephrine transporterAccumulationCellsGamma-aminobutyric acidCotransportDAGradientStoichiometrySubstrateAbsenceTransport processes
1994
Ligand binding to the serotonin transporter: equilibria, kinetics, and ion dependence.
Humphreys C, Wall S, Rudnick G. Ligand binding to the serotonin transporter: equilibria, kinetics, and ion dependence. Biochemistry 1994, 33: 9118-25. PMID: 8049215, DOI: 10.1021/bi00197a014.Peer-Reviewed Original Research
1993
From synapse to vesicle: The reuptake and storage of biogenic amine neurotransmitters
Rudnick G, Clark J. From synapse to vesicle: The reuptake and storage of biogenic amine neurotransmitters. Biochimica Et Biophysica Acta 1993, 1144: 249-263. PMID: 8104483, DOI: 10.1016/0005-2728(93)90109-s.Peer-Reviewed Reviews, Practice Guidelines, Standards, and Consensus StatementsConceptsPresynaptic plasma membraneBiogenic amine neurotransmittersEndogenous regulatory mechanismsSynaptic transmitter levelsPlasma membraneIndividual proteinsRegulatory mechanismsTransport systemMolecular levelSynaptic vesiclesAmine neurotransmittersIon gradientsTransportersVesiclesCDNARapid progressProteinNeurotransmittersRegulationMechanismMembraneSynapseTransmitter levels
1992
Expression of a cloned gamma-aminobutyric acid transporter in mammalian cells.
Keynan S, Suh Y, Kanner B, Rudnick G. Expression of a cloned gamma-aminobutyric acid transporter in mammalian cells. Biochemistry 1992, 31: 1974-9. PMID: 1536839, DOI: 10.1021/bi00122a011.Peer-Reviewed Original ResearchMeSH KeywordsAnimalsBiological TransportCarrier ProteinsChloridesCloning, MolecularDNAGABA Plasma Membrane Transport ProteinsGamma-Aminobutyric AcidGene ExpressionGenetic VectorsHeLa CellsHumansKineticsL CellsMembrane ProteinsMembrane Transport ProteinsMiceNerve Tissue ProteinsOrganic Anion TransportersPlasmidsPrecipitin TestsRatsSodiumTransfectionTunicamycinXenopusConceptsMammalian cellsGABA transportMouse Ltk- cellsT7 RNA polymerasePlasma membrane vesiclesL cellsApparent molecular massGABA transporterSynaptic plasma membrane vesiclesGamma-aminobutyric acid transporterPresence of tunicamycinEukaryotic expression vectorRNA polymeraseTransient expressionExpression vectorAcid transportersMembrane vesiclesStable expressionLtk- cellsFunctional expressionGAT-1Molecular massHeLa cellsTransportersTransfection
1991
Binding of the cocaine analog 2 beta-[3H] carboxymethoxy-3 beta-(4-fluorophenyl)tropane to the serotonin transporter.
Rudnick G, Wall S. Binding of the cocaine analog 2 beta-[3H] carboxymethoxy-3 beta-(4-fluorophenyl)tropane to the serotonin transporter. Molecular Pharmacology 1991, 40: 421-6. PMID: 1896028.Peer-Reviewed Original Research
1988
Antidepressant binding to the porcine and human platelet serotonin transporters.
Humphreys C, Levin J, Rudnick G. Antidepressant binding to the porcine and human platelet serotonin transporters. Molecular Pharmacology 1988, 33: 657-63. PMID: 3380080.Peer-Reviewed Original Research
1985
Serotonin Transport by Platelet Plasma and Granule Membranes
RUDNICK G, HUMPHREYS C, DEAN G. Serotonin Transport by Platelet Plasma and Granule Membranes. Annals Of The New York Academy Of Sciences 1985, 456: 277-278. PMID: 2418730, DOI: 10.1111/j.1749-6632.1985.tb14876.x.Peer-Reviewed Reviews, Practice Guidelines, Standards, and Consensus StatementsEffects of monovalent cations on Semliki Forest virus entry into BHK-21 cells.
Helenius A, Kielian M, Wellsteed J, Mellman I, Rudnick G. Effects of monovalent cations on Semliki Forest virus entry into BHK-21 cells. Journal Of Biological Chemistry 1985, 260: 5691-5697. PMID: 3988769, DOI: 10.1016/s0021-9258(18)89078-0.Peer-Reviewed Original ResearchConceptsSemliki Forest virusEndosome membraneViral envelopeBaby hamster kidney cellsMammalian cellsEndosomal membranesLow endosomalBHK-21 cellsHamster kidney cellsVirus endocytosisIntact cellsConformational changesEndosomesPrelysosomal endosomesViral spike glycoproteinVirus fusionKidney cellsAcidic endosomal pHViral RNAVoltage-sensitive probeEndocytosisVirus entryEndosomal pHCellsSpike glycoprotein
1983
Hydrogen ion cotransport by the renal brush border glutamate transporter.
Nelson P, Dean G, Aronson P, Rudnick G. Hydrogen ion cotransport by the renal brush border glutamate transporter. Biochemistry 1983, 22: 5459-63. PMID: 6140027, DOI: 10.1021/bi00292a030.Peer-Reviewed Original ResearchThe serotonin transporter-imipramine "receptor".
Talvenheimo J, Fishkes H, Nelson P, Rudnick G. The serotonin transporter-imipramine "receptor". Journal Of Biological Chemistry 1983, 258: 6115-6119. PMID: 6853478, DOI: 10.1016/s0021-9258(18)32380-9.Peer-Reviewed Original ResearchSodium ion requirements for serotonin transport and imipramine binding.
Rudnick G, Talvenheimo J, Fishkes H, Nelson P. Sodium ion requirements for serotonin transport and imipramine binding. Psychopharmacology Bulletin 1983, 19: 545-9. PMID: 6635128.Peer-Reviewed Original Research
1981
Anion-dependent sodium ion conductance of platelet plasma membranes.
Nelson P, Rudnick G. Anion-dependent sodium ion conductance of platelet plasma membranes. Biochemistry 1981, 20: 4246-9. PMID: 6269584, DOI: 10.1021/bi00518a002.Peer-Reviewed Original Research