SLC2A3 (Solute Carrier Family 2 Member 3) encodes GLUT3 (Glucose Transporter 3), a high-affinity glucose transporter with the highest uptake capacity among GLUT family members. While GLUT1 (SLC2A1) mediates basal glucose uptake across the blood-brain barrier, GLUT3 provides the high-affinity uptake system essential for neuronal glucose acquisition[1]. The Km for glucose of GLUT3 (~1-2 mM) is substantially lower than plasma glucose concentrations (~5 mM), ensuring efficient glucose uptake even when blood glucose is relatively low.
GLUT3 is predominantly expressed in neurons, particularly in regions with high metabolic demand including the cerebral cortex, hippocampus, and cerebellar Purkinje cells. This neuron-specific expression pattern makes GLUT3 critical for cognitive function and vulnerable in neurodegenerative diseases. In Alzheimer's disease (AD) and Parkinson's disease (PD), GLUT3 expression and function are altered, contributing to metabolic deficits that precede overt neurodegeneration[2]. The brain's dependence on continuous glucose supply, combined with GLUT3's role as the primary neuronal glucose uptake system, positions this transporter as both a diagnostic biomarker candidate and therapeutic target.
| Property | Value |
|---|---|
| Gene Symbol | SLC2A3 |
| Full Name | Solute Carrier Family 2 Member 3 (GLUT3) |
| Chromosomal Location | 12p13.31 |
| NCBI Gene ID | 6503 |
| OMIM | 138170 |
| Ensembl ID | ENSG00000146670 |
| UniProt ID | P11166 |
| Protein Family | Major Facilitator Superfamily (MFS) |
GLUT3 catalyzes facilitative glucose diffusion:
Transport mechanism: Alternating access (rocker-switch model)
Direction: Bidirectional, following concentration gradient
Substrates: D-Glucose, D-Galactose, D-Mannose
Inhibitors: Cytochalasin B, phloretin, forskolin
GLUT3 exhibits distinctive kinetics[3]:
| Parameter | GLUT3 | GLUT1 | GLUT4 |
|---|---|---|---|
| Km (glucose) | 1-2 mM | ~7 mM | ~5 mM |
| Vmax | High | Moderate | High |
| Tissue | Neurons | BBB | Muscle/fat |
The low Km enables efficient glucose uptake at physiological glucose concentrations, providing neurons with autonomous glucose sensing capabilities.
GLUT3 is a polytopic membrane protein with:
GLUT3 serves as the primary glucose uptake system in neurons[1:1]:
| Brain Region | GLUT3 Expression | Functional Significance |
|---|---|---|
| Cerebral Cortex | Very High | Cognitive processing |
| Hippocampus | High | Memory circuits |
| Cerebellum | High | Motor coordination |
| Basal Ganglia | Moderate | Movement control |
| Brain Stem | Moderate | Vital functions |
| Spinal Cord | Moderate | Sensory/motor |
In AD, GLUT3 alterations contribute to metabolic deficits[4]:
1. Reduced Expression: GLUT3 protein and mRNA decreased in AD brain
2. Impaired Trafficking: Reduced dendritic localization
3. Energy Deficits: Precedes clinical symptoms
4. Correlation with Cognition: GLUT3 correlates with MMSE scores
Mechanisms linking GLUT3 to AD:
GLUT3 in PD[5]:
1. Dopaminergic neuron vulnerability: High GLUT3 in vulnerable neurons
2. Mitochondrial dysfunction: Links to metabolic stress
3. Activity changes: Altered regulation in PD brain
4. Therapeutic implications: GLUT3 modulators in development
GLUT3 alterations in:
GLUT3 represents a promising target[6]:
1. Up-regulators: Increase GLUT3 expression
2. Activity enhancers: Improve transport kinetics
3. Trafficking modulators: Improve dendritic targeting
4. Combination approaches: With metabolic therapies
| Strategy | Disease | Status |
|---|---|---|
| GLUT3 upregulators | AD | Research |
| Metabolic therapy | PD | Preclinical |
| Gene therapy | Neurodegeneration | Exploratory |
| Small molecules | HD | Research |
GLUT3 as biomarker:
GLUT3 interacts with:
| Interactor | Interaction Type | Functional Consequence |
|---|---|---|
| GLUT1 | Complementary | BBB uptake |
| GLUT4 | Metabolic link | Activity regulation |
| GLUT2 | Tissue distribution | Liver/brain balance |
| Insulin signaling | Pathway cross-talk | Regulation |
| AMPK | Energy sensing | Activity modulation |
| Mitochondria | Metabolic coupling | Energy production |
| VEGF | Angiogenesis | Blood flow |
SLC2A3 encodes GLUT3, the high-affinity neuronal glucose transporter essential for brain glucose acquisition. With a Km substantially lower than other GLUTs, GLUT3 ensures neurons obtain sufficient glucose even during metabolic stress. GLUT3 is critical for cognitive function, regional brain metabolism, and neuronal survival. In neurodegenerative diseases, GLUT3 alterations contribute to metabolic deficits that precede and drive neurodegenerative processes. The transporter's central role in neuronal metabolism, combined with its disease-associated changes, makes it a promising therapeutic target. Ongoing research aims to develop GLUT3-modulating compounds, gene therapies, and diagnostic approaches for AD, PD, and related disorders.
Zhao F, et al. GLUT3 in neuronal glucose uptake and disease. Journal of Neuroscience Research. 2018. ↩︎ ↩︎
Chen Y, et al. Neuronal glucose transporters in brain metabolism. Neuroscience. 2018. ↩︎
Kandasamy P, et al. SLC transporters as therapeutic targets. European Journal of Pharmaceutical Sciences. 2020. ↩︎
Liu X, et al. Targeting GLUT3 for Alzheimer's disease therapy. Journal of Alzheimer's Disease. 2024. ↩︎
Kim S, et al. GLUT3 in Parkinson's disease models. Neurobiology of Disease. 2023. ↩︎
Dang S, et al. GLUT3 modulators and cerebral metabolism. Pharmacology & Therapeutics. 2023. ↩︎