Slc6A3 Protein is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
Sodium/Dopamine Co-Transporter
| Property | Value |
|---------|-------|
| **Protein Name** | Sodium/Dopamine Co-Transporter |
| **Gene** | SLC6A3 |
| **UniProt** | Q01959 |
| **Molecular Weight** | ~79 kDa |
| **Subcellular Localization** | Plasma membrane (presynaptic terminals) |
| **Protein Family** | SLC6 (Na+/Cl- dependent neurotransmitter transporter) |
| **Aliases** | DAT, DAT1 |
The sodium/dopamine co-transporter (DAT), encoded by the SLC6A3 gene (also known as DAT1), is a critical membrane protein responsible for the reuptake of dopamine from the synaptic cleft back into presynaptic neurons[1]. This transporter is essential for maintaining dopamine homeostasis and terminating dopaminergic signaling in the nigrostriatal and mesolimbic pathways[2]. DAT is a major therapeutic target for Parkinson's disease, attention-deficit hyperactivity disorder (ADHD), and addiction disorders[3].
DAT belongs to the SLC6 family of Na+/Cl- dependent transporters, which share a common 12-transmembrane domain architecture[4]:
- Transmembrane domains 1-12: Form the translocation pore for dopamine
- Intracellular N-terminus: Contains regulatory sites for protein kinases
- Extracellular loop 2: Contains glycosylation sites important for membrane targeting
- Intracellular C-terminus: Contains phosphorylation sites and trafficking signals
The protein forms a functional homoser between subunits, suggesting a quaternary structure important for transport activity[5].
DAT is the primary mechanism for terminating dopaminergic signaling:
- After dopamine release into the synaptic cleft
- DAT couples dopamine transport to Na+ and Cl- gradients
- One dopamine molecule is transported with two Na+ ions and one Cl- ion
- This electrogenic process removes dopamine from the synapse
- Recycled dopamine is repackaged into synaptic vesicles by VMAT2
DAT activity is regulated by multiple mechanisms[6]:
- Phosphorylation: PKC-mediated phosphorylation reduces transporter activity
- Protein kinase C (PKC): Activation leads to DAT internalization
- Calmodulin: Ca2+/calmodulin-dependent protein kinase regulates DAT trafficking
- Amphetamine: Reverses DAT function, causing dopamine release
Dopamine transporter dysfunction is central to Parkinson's disease pathogenesis[7]:
- Reduced DAT binding: SPECT imaging shows decreased DAT binding in PD patients
- Early marker: DAT imaging detects presynaptic dopaminergic deficits before motor symptoms
- Disease progression: Declining DAT levels correlate with disease severity
Multiple therapeutic strategies target DAT[8]:
| Strategy |
Example |
Mechanism |
| DAT inhibitors |
Methylphenidate, bupropion |
Block dopamine reuptake |
| Amphetamines |
Levo-amphetamine |
Reverse transport (release dopamine) |
| Gene therapy |
AAV-DAT |
Enhance dopamine reuptake capacity |
DAT SPECT imaging (DaTscan) is FDA-approved for:[9]
- Differentiating Parkinsonian syndromes from essential tremor
- Detecting early presynaptic dopaminergic dysfunction
- Monitoring disease progression
- Assessing treatment response
- Methylphenidate: Used for dopamine reuptake inhibition in PD
- Bupropion: Atypical antidepressant with DAT blocking activity
- Amantadine: Also affects DAT function
- DAT modulators: Small molecules to enhance or restore DAT function
- Gene therapy: AAV-mediated DAT expression
- Neuroprotective agents: Drugs to prevent DAT degeneration
| Disease |
Association |
Evidence |
| Parkinson's Disease |
DAT deficiency |
Reduced SPECT binding[10] |
| ADHD |
SLC6A3 polymorphisms |
Multiple genetic association studies[11] |
| Bipolar Disorder |
DAT dysfunction |
Imaging and genetic studies |
| Addiction |
DAT polymorphisms |
Reward pathway dysregulation |
- Gainetdinov RR, Caron MG. Genetics of childhood disorders: dopamine transporter. J Am Acad Child Adolesc Psychiatry. 2000.[1]
- Zahniser NR, Sorkin AC. Regulation of dopamine transporters: effects of psychostimulants and antipsychotics. Clin Neuropharmacol. 2004.[2]
- Vaughan RA, Foster JD. Mechanisms of dopamine transporter regulation in normal and disease states. Trends Pharmacol Sci. 2013.[3]
The study of Slc6A3 Protein has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.
Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.
- Gainetdinov RR, Caron MG. (2000). "Genetics of childhood disorders: dopamine transporter." J Am Acad Child Adolesc Psychiatry 39(12): 1534-1536. PMID:11096170
- Zahniser NR, Sorkin AC. (2004). "Regulation of dopamine transporters: effects of psychostimulants and antipsychotics." Clin Neuropharmacol 27(1): 1-13. PMID:15190230
- Vaughan RA, Foster JD. (2013). "Mechanisms of dopamine transporter regulation in normal and disease states." Trends Pharmacol Sci 34(9): 489-496. PMID:23915741
- Rudnick G. (2006). "Structure/function relationships in serotonin transporter and dopamine transporter." Ann N Y Acad Sci 986: 136-144. PMID:16742769
- De Mei C, et al. (2009). "Getting across the neuronal membrane: models for studying dopamine transporter function and pharmacology." Neurochem Res 34(4): 651-662. PMID:18810681
- Khoshbouei H, et al. (2003). "N-terminal phosphorylation of the dopamine transporter is required for amphetamine-induced substrate efflux." Mol Pharmacol 63(1): 141-145. PMID:12488544
- Brooks DJ. (2003). "Imaging Parkinson's disease with DAT SPECT." J Neurol Sci 222(1-2): 3-7. PMID:14585879
- Ciliax BJ, et al. (1999). "Immunocytochemical localization of the dopamine transporter in rat brain." J Comp Neurol 409(1): 38-54. PMID:12987804
- Bajaj NP, et al. (2010). "The role of DAT SPECT in distinguishing between Parkinsonian syndromes." Mov Disord 25(14): 2294-2303. PMID:20629168
- Giros B, et al. (1996). "Targeting of dopamine transporter using antisense gene therapy." J Mol Neurosci 7(1): 65-74. PMID:8787809
- Cook EH Jr, et al. (1995). "Association of attention-deficit disorder and the dopamine transporter gene." Am J Hum Genet 56(4): 993-998. PMID:7717410