A C-terminal PDZ domain-binding sequence is required for striatal distribution of the dopamine transporter

• Published in: Nature communications Vol. 4; no. 1; p. 1580
• Main Authors: Rickhag, Mattias, Hansen, Freja Herborg, Sørensen, Gunnar, Strandfelt, Kristine Nørgaard, Andresen, Bjørn, Gotfryd, Kamil, Madsen, Kenneth L., Vestergaard Klewe, Ib, Ammendrup-Johnsen, Ina, Eriksen, Jacob, Newman, Amy H., Füchtbauer, Ernst-Martin, Gomeza, Jesus, Woldbye, David P.D., Wörtwein, Gitta, Gether, Ulrik
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 2013; Nature Publishing Group
• Subjects: 631/378/1697; 631/378/548/1964; Amino Acid Sequence; Amphetamine - pharmacology; Animals; Behavior, Animal - drug effects; Binding Sites; Biological Transport - drug effects; Carrier Proteins - metabolism; Dopamine - metabolism; Dopamine Plasma Membrane Transport Proteins - chemistry; Dopamine Plasma Membrane Transport Proteins - metabolism; Dopaminergic Neurons - drug effects; Dopaminergic Neurons - metabolism; Endocytosis - drug effects; Endoplasmic Reticulum - drug effects; Endoplasmic Reticulum - metabolism; Humanities and Social Sciences; Immunohistochemistry; Locomotion - drug effects; Mice; Mice, Knockout; multidisciplinary; Mutation - genetics; Neostriatum - drug effects; Neostriatum - metabolism; Nuclear Proteins - metabolism; PDZ Domains; Phenotype; Presynaptic Terminals - drug effects; Presynaptic Terminals - metabolism; Protein Binding - drug effects; Science; Science (multidisciplinary); Structure-Activity Relationship
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms2568

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. The mechanisms controlling dopamine transporter (DAT) levels in the striatum are poorly understood. Rickhag and colleagues generate DAT knock-in mice with disrupted PDZ-binding motifs and find that PDZ-domain interactions are necessary for distribution of DAT to striatal nerve terminals.