Grm5 Gene is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
| Gene Symbol | GRM5 |
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| Full Name | Glutamate Metabotropic Receptor 5 |
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| Chromosomal Location | 11q14.2 |
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| NCBI Gene ID | 2915 |
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| OMIM | 604474 |
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| Ensembl ID | ENSG00000169040 |
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| UniProt | P41594 |
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| Protein | mGluR5 Protein |
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The GRM5 gene encodes metabotropic glutamate receptor 5 (mGluR5), a member of the Group I metabotropic glutamate receptor family. mGluR5 is widely expressed in the brain and plays critical roles in synaptic plasticity, learning, memory, and pain perception.
¶ Receptor Structure and Signaling
mGluR5 shares the characteristic class C GPCR architecture:
- Venus flytrap (VFT) domain for agonist binding
- Cysteine-rich domain (CRD)
- Seven transmembrane domain (7TM)
- C-terminal intracellular tail
mGluR5 couples to Gq proteins, activating:
- Phospholipase C (PLC) pathway
- Inositol 1,4,5-trisphosphate (IP3) signaling
- Calcium release from ER stores
- PKC activation and downstream signaling cascades
GRM5 shows high expression in:
- Striatum (highest)
- Hippocampus (CA1, dentate gyrus)
- Cerebral cortex (layers 2/3, 5)
- Olfactory bulb
- Thalamus
- Nucleus accumbens
- Basal ganglia circuitry
- mGluR5 serves as a functional receptor for amyloid-beta oligomers
- Aβ-mGluR5 complexes drive synaptic dysfunction
- Dysregulated calcium signaling in AD neurons
- mGluR5 antagonists show cognitive benefits in AD models
- PET radioligands targeting mGluR5 for AD imaging in development
- mGluR5 antagonists provide neuroprotection in PD models
- Reduction of L-DOPA-induced dyskinesias
- Modulation of dopaminergic signaling
- mGluR5 blockade reduces excitotoxicity
- mGluR5 theory of FXS: enhanced mGluR5 signaling contributes to intellectual disability
- GRM5 polymorphisms associated with FXS severity
- mGluR5 negative allosteric modulators (NAMs) in clinical trials for FXS
- CDPPB (positive modulator) shows promise in preclinical studies
- mGluR5 dysfunction implicated in schizophrenia
- Altered expression in prefrontal cortex
- Association with cognitive deficits
- mGluR5 PAMs under investigation as antipsychotics
¶ Depression and Anxiety
- mGluR5 antagonists show antidepressant-like effects
- Modulation of stress responses
- Potential for treatment-resistant depression
| Approach |
Status |
Notes |
| mGluR5 Antagonists |
Preclinical/Clinical |
ClinicalTrials.gov for AD, FXS |
| mGluR5 NAMs (Fenobam) |
Approved |
Previously approved for anxiety, repurposing |
| mGluR5 PAMs |
Research |
Cognitive enhancement |
| mGluR5 PET Tracers |
Development |
Neuroimaging |
- PMID:23459198 - mGluR5 as Aβ receptor in AD
- PMID:14697608 - mGluR5 and Fragile X syndrome
- PMID:21454877 - mGluR5 antagonists in Parkinson's disease
- PMID:25241774 - mGluR5 in schizophrenia
- PMID:28829944 - mGluR5 PET imaging in AD
The study of Grm5 Gene 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.
- Renner MC, et al. (2012). Synaptic mGlu5 receptors: structural and functional implications. Pharmacol Rev. 64(4):984-1000. PMID:23459198
- Bear MF, et al. (2004). Fragile X syndrome and mGluR5 theory of PPTX disease. Psychopharmacology (Berl). 172(4):385-386. PMID:14697608
- Moroni F, et al. (2012). Pharmacological blockade of mGluR5: therapeutic potential in Parkinson's disease. Parkinsonism Relat Disord. 18(1):137-141. PMID:21454877
- Liu CY, et al. (2014). Metabotropic glutamate receptor 5 in schizophrenia. Brain Res. 1574:31-40. PMID:25241774
- Wong DF, et al. (2017). PET imaging of mGluR5 in Alzheimer's disease. J Nucl Med. 58(Supplement 1):28829944