GALR2 (Galanin Receptor 2) is a G protein-coupled receptor that mediates the neuroprotective and modulatory effects of the neuropeptide galanin in the central and peripheral nervous systems. Unlike its sibling receptor GALR1, GALR2 couples to both Gq and Gi/o proteins, enabling diverse signaling pathways relevant to neurodegeneration, neuroprotection, and synaptic plasticity. This page covers the gene's normal function, disease associations, expression patterns, and key research findings relevant to neurodegenerative diseases.
| Symbol | GALR2 |
|---|---|
| Full Name | Galanin Receptor 2 |
| Chromosomal Location | 17q25.3 |
| NCBI Gene ID | [9512](https://www.ncbi.nlm.nih.gov/gene/9512) |
| OMIM | [607311](https://www.omim.org/entry/607311) |
| Ensembl ID | ENSG00000141404 |
| UniProt | O43603 |
| Associated Diseases | [Alzheimer's Disease](/diseases/alzheimers-disease), [Parkinson's Disease](/diseases/parkinsons-disease), Neuropathic Pain, Depression, Epilepsy, Stroke |
The GALR2 gene is located on chromosome 17q25.3 and encodes a 369 amino acid GPCR belonging to the galanin receptor family. The gene structure includes 4 exons spanning approximately 25 kb, with multiple transcription start sites and alternative splicing generating variant isoforms.
GALR2 is evolutionarily conserved across vertebrates, sharing structural features with other galanin receptors: seven transmembrane domains, extracellular N-terminus, and intracellular C-terminus with phosphorylation sites.
GALR2 exhibits unique signaling properties compared to GALR1:
Upon galanin binding, GALR2 activates Gq proteins, leading to:
GALR2 can also couple to Gi/o proteins:
GALR2 activation provides robust neuroprotection against excitotoxic insults:
The mechanisms include PKC-mediated anti-apoptotic signaling, PI3K/Akt pathway activation, and mitochondrial protection.
[1] demonstrated the neuroprotective effects of GALR2 activation.
GALR2 neuroprotection extends to oxidative stress models through Nrf2/ARE pathway activation, antioxidant gene expression, and mitochondrial biogenesis.
GALR2 regulates synaptic transmission and plasticity:
GALR2 exhibits widespread but distinct expression:
| Brain Region | Expression Level | Primary Cell Types |
|---|---|---|
| Hippocampus | High | CA1/CA3 pyramidal neurons, dentate gyrus granule cells |
| Hypothalamus | High | Paraventricular nucleus, supraoptic nucleus neurons |
| Amygdala | Moderate-High | Principal neurons, interneurons |
| Spinal Cord | Moderate-High | Dorsal horn neurons, motor neurons |
| Dorsal Root Ganglion | High | Sensory neurons |
In neurons, GALR2 localizes to dendrites and dendritic spines, axon terminals, postsynaptic densities, and soma.
GALR2 plays complex roles in AD pathogenesis:
GALR2 has emerged as a significant neuroprotective target in PD:
[2] demonstrated GALR2 neuroprotection in Parkinson's disease models.
GALR2 is a key mediator of pain modulation:
GALR2 is implicated in depression pathophysiology:
Small molecule and peptide agonists are under development:
| Condition | Therapeutic Approach | Status |
|---|---|---|
| Alzheimer's Disease | GALR2 agonists | Preclinical |
| Parkinson's Disease | GALR2 agonists | Preclinical |
| Neuropathic Pain | GALR2 agonists | Phase I/II |
| Depression | GALR2 agonists | Preclinical |
Galr2 knockout mice exhibit enhanced anxiety-like behavior, deficits in spatial memory, and altered pain threshold. GALR2 overexpression provides enhanced neuroprotection in disease models.
Mitsukawa et al. Galanin receptor 2/3 neuroprotection. J Mol Neurosci. 2010. ↩︎
Holmes et al. GALR2 in Parkinson's disease. J Neurosci. 2011. ↩︎