2.A.22.1.3
Dopamine:Na⁺ symporter, DAT (also takes up amphetamines in symport with Na⁺ which promotes intracellular Na⁺-dependent dopamine efflux (Khoshbouei et al., 2003)). It is inhibited by cocaine, amphetamines, neurotoxins, antidepressants and ethanol (Chen et al., 2004)]. Zn²⁺ potentiates uncoupled Cl^- conductance (Meinild et al., 2004).  A conserved salt bridge between TMSs 1 and 10 constitutes an extracellular gate (Pedersen et al. 2014). The 3-D structure of DAT is known (PDB 4M48; 4XPA).  P101 of DAT plays an essential role in DA translocation (Lin and Uhl 2005). DAT is regulated by D3 dopamine receptors (Zapata et al., 2007). P25α (tubulin polymerization-promoting protein, TPPP (UniProt acc # O94811) increases dopamine transporter localization to the plasma membrane (Fjorback et al., 2011). DAT mediates paraquat (an herbicide) neurotoxicity (Rappold et al., 2011).  Membrane cholesterol modulates the outward facing conformation and alters cocaine binding (Hong and Amara 2010).  Threonine-53 phosphorylation in the rat orthologue (P23977) (Serine 53 in the human transporter) regulates substrate reuptake and amphetamine-stimulated efflux (Foster et al. 2012).  DAT is enriched in filopodia and induces filopodia formation (Caltagarone et al. 2015).  Dasotraline is an inhibitor of dopamine and norepinephrine reuptake, used for the treatment of attention-deficit/hyperactivity disorder (ADHD) (Hopkins et al. 2015). When in complex with 1-(1-benzofuran-5-yl)-N-methylpropan-2-amine (5-MAPB), a psychoactive adictive agonists, DAT can exhibit conformational transitions that spontaneously isomerize the transporter into the inward-facing state, similarly to that observed in dopamine-bound DAT (Sahai et al. 2016).  The cytoplasmic N- and C-terminal domains contribute to substrate and inhibitor binding (Sweeney et al. 2016). DAT can exist as a monomer, a cooperative dimer subject to allosteric regulation (Cheng et al. 2017) or an oligomer involving the scaffold domain but not the bundle domain (Jayaraman et al. 2018). Cocaine binds in the S1 site to stabilize an inactive form of DAT (Krout et al. 2017). Dopamine efflux is caused by 3,4-methylenedioxypyrovalerone (MDPV) (Shekar et al. 2017). The cholesterol binding sites observed in the DAT crystal structures may be preserved in all human monoamine transporters (dopamine, serotonin and norepinephrine) and when cholesterol is bound, transport is inhibited (Zeppelin et al. 2018).  The cell permeable furopyrimidine, AIM-100, augments DAT oligomerization through an allosteric mechanism associated with the DAT conformational state, and oligomerization-triggered clustering leads to a coat-independent endocytosis and subsequent endosomal retention of DAT (Sorkina et al. 2018). Dysfunction of this transporter leads to disease states, such as Parkinson's disease, bipolar disorder and/or depression (Jayaraman et al. 2018). DAT dysfunction is linked to neuropsychiatric disorders including attention-deficit/hyperactivity disorder (ADHD), bipolar disorder (BPD), and autism spectrum disorder (ASD). The DAT Val559 mutation changes the transporter localization and lateral mobility that contributes to ADE and alterations in dopamine signaling underlying multiple neuropsychiatric disorders (Thal et al. 2018). A  tight spatial and functional relationship between the DAT/GLT-1 transporters and the Kv7.2/7.3 potassium channel immediately readjusts the membrane potential of the neuron, probably to limit the neurotransmitter-mediated neuronal depolarization (Bartolomé-Martín et al. 2019). Evidence for the association of polymorphisms of DAT1 (SLC6A3) with heroin dependence has been presented (Koijam et al. 2020). A direct coupling between conformational dynamics of DAT, functional activity of the transporter and its oligomerization leading to endocytosis has been documented (Sorkina et al. 2021). Association of the sigma-1 receptor with the dopamine transporter attenuates the binding of methamphetamine via helix-helix interactions (Xu and Chen 2021). Potential partners for DAT, include the transmembrane chaperone 4F2hc (TC# 8.A.9.2.2), the proteolipid M6a (TC# 9.B.38.1.1) and a potential membrane receptor for progesterone (PGRMC2) (TC# 9.B.433.1.1) (Piniella et al. 2021). Two cytoplasmic proteins: a component of the Cullin1-dependent ubiquitination machinery termed F-box/LRR-repeat protein 2 (FBXL2; Q9UKC9), and the enzyme inositol 5-phosphatase 2 (SHIP2; O15357) were also associated. M6a, SHIP2 and Cullin1 were shown to increase DAT activity in coexpression experiments. M6a, enriched in neuronal protrusions (filopodia or dendritic spines), colocalized with DAT in these structures. In addition, the product of SHIP2 enzymatic activity (phosphatidylinositol 3,4-bisphosphate [PI(3,4)P2]) was tightly associated with DAT. PI(3,4)P2 strongly stimulated transport activity in electrophysiological recordings, and conversely, inhibition of SHIP2 reduced DA uptake (Piniella et al. 2021). There are weak associations between DAT mRNA expression and DAT availability in human brains (Pak et al. 2022). Gender differences in cocaine-induced hyperactivity and dopamine transporter trafficking to the plasma membrane have been reported (Deng et al. 2022). The dopamine transporter and synaptic vesicle sorting defects underlie auxilin-associated Parkinson's disease (Vidyadhara et al. 2023). DAT may play a role in Parkinson's disease (Zhou et al. 2023). Dopamine transporter (DAT) deficient rodents have been characterized suggesting perspectives and limitations for neuroscience (Savchenko et al. 2023). Epigenetic analyses of the dopamine transporter gene DAT1 through methylation have reveaed the basis for certain personality traits in athletes (Humińska-Lisowska et al. 2023). Interactions of calmodulin kinase II with the dopamine transporter facilitate cocaine-induced enhancement of evoked dopamine release (Keighron et al. 2023). Known data on the consequences of changes in DAT expression in experimental animals, and results of pharmacological studies in these animals have been reviewed (Savchenko et al. 2023). DAT knockout rats display epigenetic alterations in response to cocaine exposure, and targeting epigenetic modulators, Lysine Demethylase 6B (KDM6B) and Bromodomain-containing protein 4 (BRD4)may be therapeutic in treating addiction-related behaviors in aBartolomé-Martín et al. 2019). Evidence for the association of polymorphisms of DAT1 (SLC6A3) with heroin dependence has been presented (Koijam et al. 2020). A direct coupling between conformational dynamics of DAT, functional activity of the transporter and its oligomerization leading to endocytosis has been documented (Sorkina et al. 2021). Association of the sigma-1 receptor with the dopamine transporter attenuates the binding of methamphetamine via helix-helix interactions (Xu and Chen 2021). Potential partners for DAT, include the transmembrane chaperone 4F2hc (TC# 8.A.9.2.2), the proteolipid M6a (TC# 9.B.38.1.1) and a potential membrane receptor for progesterone (PGRMC2) (TC# 9.B.433.1.1) (Piniella et al. 2021). Two cytoplasmic proteins: a component of the Cullin1-dependent ubiquitination machinery termed F-box/LRR-repeat protein 2 (FBXL2; Q9UKC9), and the enzyme inositol 5-phosphatase 2 (SHIP2; O15357) were also associated. M6a, SHIP2 and Cullin1 were shown to increase DAT activity in coexpression experiments. M6a, enriched in neuronal protrusions (filopodia or dendritic spines), colocalized with DAT in these structures. In addition, the product of SHIP2 enzymatic activity (phosphatidylinositol 3,4-bisphosphate [PI(3,4)P2]) was tightly associated with DAT. PI(3,4)P2 strongly stimulated transport activity in electrophysiological recordings, and conversely, inhibition of SHIP2 reduced DA uptake (Piniella et al. 2021). There are weak associations between DAT mRNA expression and DAT availability in human brains (Pak et al. 2022). Gender differences in cocaine-induced hyperactivity and dopamine transporter trafficking to the plasma membrane have been reported (Deng et al. 2022). The dopamine transporter and synaptic vesicle sorting defects underlie auxilin-associated Parkinson's disease (Vidyadhara et al. 2023). DAT may play a role in Parkinson's disease (Zhou et al. 2023). Dopamine transporter (DAT) deficient rodents have been characterized suggesting perspectives and limitations for neuroscience (Savchenko et al. 2023). Epigenetic analyses of the dopamine transporter gene DAT1 through methylation have reveaed the basis for certain personality traits in athletes (Humińska-Lisowska et al. 2023). Interactions of calmodulin kinase II with the dopamine transporter facilitate cocaine-induced enhancement of evoked dopamine release (Keighron et al. 2023). Known data on the consequences of changes in DAT expression in experimental animals, and results of pharmacological studies in these animals have been reviewed (Savchenko et al. 2023). DAT knockout rats display epigenetic alterations in response to cocaine exposure, and targeting epigenetic modulators, Lysine Demethylase 6B (KDM6B) and Bromodomain-containing protein 4 (BRD4)may be therapeutic in treating addiction-related behaviors in a sex-dependent manner (Vilca et al. 2023).