title: A C-terminal PDZ domain-binding sequence is required for striatal distribution of the dopamine transporter.
abstract: The dopamine transporter mediates reuptake of dopamine from the synaptic cleft. The cellular mechanisms controlling dopamine transporter levels in striatal nerve terminals remain poorly understood. The dopamine transporters contain a C-terminal PDZ (PSD-95/Discs-large/ZO-1) domain-binding sequence believed to bind synaptic scaffolding proteins, but its functional significance is uncertain. Here we demonstrate that two different dopamine transporter knock-in mice with disrupted PDZ-binding motifs (dopamine transporter-AAA and dopamine transporter+Ala) are characterized by dramatic loss of dopamine transporter expression in the striatum, causing hyperlocomotion and attenuated response to amphetamine. In cultured dopaminergic neurons and striatal slices from dopamine transporter-AAA mice, we find markedly reduced dopamine transporter surface levels and evidence for enhanced constitutive internalization. In dopamine transporter-AAA neurons, but not in wild-type neurons, surface levels are rescued in part by expression of a dominant-negative dynamin mutation (K44A). Our findings suggest that PDZ-domain interactions are critical for synaptic distribution of dopamine transporter in vivo and thereby for proper maintenance of dopamine homoeostasis.
authors.affiliation: Molecular Neuropharmacology Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Mattias
authors.initials: M
authors.lastname: Rickhag
authors.forename: Freja Herborg
authors.initials: FH
authors.lastname: Hansen
authors.forename: Gunnar
authors.initials: G
authors.lastname: Sørensen
authors.forename: Kristine Nørgaard
authors.initials: KN
authors.lastname: Strandfelt
authors.forename: Bjørn
authors.initials: B
authors.lastname: Andresen
authors.forename: Kamil
authors.initials: K
authors.lastname: Gotfryd
authors.forename: Kenneth L
authors.initials: KL
authors.lastname: Madsen
authors.forename: Ib
authors.initials: I
authors.lastname: Vestergaard-Klewe
authors.forename: Ina
authors.initials: I
authors.lastname: Ammendrup-Johnsen
authors.forename: Jacob
authors.initials: J
authors.lastname: Eriksen
authors.forename: Amy H
authors.initials: AH
authors.lastname: Newman
authors.forename: Ernst-Martin
authors.initials: EM
authors.lastname: Füchtbauer
authors.forename: Jesus
authors.initials: J
authors.lastname: Gomeza
authors.forename: David P D
authors.initials: DP
authors.lastname: Woldbye
authors.forename: Gitta
authors.initials: G
authors.lastname: Wörtwein
authors.forename: Ulrik
authors.initials: U
authors.lastname: Gether
mesh_terms: D000595:Amino Acid Sequence; D000661:Amphetamine / Q000494:pharmacology; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D001665:Binding Sites; D001692:Biological Transport / Q000187:drug effects; D002352:Carrier Proteins / Q000378:metabolism; D018797:Cell Cycle Proteins; D004298:Dopamine / Q000378:metabolism; D050483:Dopamine Plasma Membrane Transport Proteins / Q000737:chemistry* / Q000378:metabolism*; D059290:Dopaminergic Neurons / Q000187:drug effects / Q000378:metabolism; D004705:Endocytosis / Q000187:drug effects; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism; D007150:Immunohistochemistry; D008124:Locomotion / Q000187:drug effects; D051379:Mice; D018345:Mice, Knockout; D009154:Mutation / Q000235:genetics; D017072:Neostriatum / Q000187:drug effects / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism; D054731:PDZ Domains; D010641:Phenotype; D017729:Presynaptic Terminals / Q000187:drug effects / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D013329:Structure-Activity Relationship
chemical_list: D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D050483:Dopamine Plasma Membrane Transport Proteins; D009687:Nuclear Proteins; C091822:Prkcabp protein, mouse; C493215:Slc6a3 protein, mouse; D000661:Amphetamine; D004298:Dopamine