Mglur5 Protein — Glutamate Metabotropic Receptor 5 is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
mGluR5 (Metabotropic Glutamate Receptor 5) is a Group I metabotropic glutamate receptor that plays crucial roles in synaptic plasticity, learning, and memory, and is a functional receptor for amyloid-beta oligomers in Alzheimer's disease.
| Attribute | Value |
|-----------|-------|
| Protein Name | Metabotropic Glutamate Receptor 5 |
| Gene | GRM5 |
| UniProt ID | P41594 |
| PDB ID | 6N51, 7LD7 | [^8]
| Molecular Weight | ~143 kDa (1211 aa) |
| Subcellular Localization | Postsynaptic density, dendritic spines |
| Protein Family | Class C GPCR, mGluR family |
mGluR5 has the characteristic Class C GPCR architecture:
- Large VFT Domain: Binds glutamate and related ligands
- Cysteine-Rich Domain: Links extracellular and transmembrane domains
- 7-TM Domain: Seven transmembrane helices (TM1-TM7)
- C-terminal Tail: Long intracellular tail with multiple interaction motifs
- Activates phospholipase Cβ (PLCβ)
- Increases IP3 and DAG production
- Releases calcium from intracellular stores
- Activates PKC
- Critical for both LTP and LTD induction
- Modulates NMDA receptor function
- Regulates AMPA receptor trafficking
¶ Learning and Memory
- Essential for hippocampal-dependent learning
- Involved in extinction learning
- Regulates gene expression via MAPK/mTOR
- Functional receptor for Aβ oligomers: Links amyloid pathology to synaptic dysfunction
- Early dysregulation in AD pathogenesis
- mGluR5 antagonists being investigated
- Modulates dopaminergic signaling
- mGluR5 antagonists reduce dyskinesias
- mGluR5 is overactive
- mGluR5 NAMs in clinical trials
¶ Depression and Anxiety
- mGluR5 antagonists have anxiolytic effects
| Drug |
Mechanism |
Status |
Indication |
| CTEP |
mGluR5 NAM |
Preclinical |
Fragile X |
| Mavoglurant |
mGluR5 NAM |
Clinical trials |
FXS, depression |
| Basimglurant |
mGluR5 NAM |
Clinical trials |
Depression |
- Conn PJ, et al. (2009). Pharmacology and functions of metabotropic glutamate receptors. Annu Rev Pharmacol Toxicol. PMID:18928405
- Huber KM, et al. (2002). Altered mGluR5-dependent signaling in a mouse model of Fragile X. Nat Neurosci. PMID:12368913
- Renner M, et al. (2010). Abeta oligomers act as a pathological signal in the brain. Neurodegener Dis. PMID:20451513
mGluR5 shows region-specific expression:
- Basal ganglia: High expression in striatum and nucleus accumbens
- Hippocampus: CA1-CA3 pyramidal cells, dentate gyrus
- Cortex: Layer V pyramidal neurons
- Thalamus: Relay nuclei
- Olfactory bulb: Mitral cells
Not expressed in cerebellum (unlike mGluR1).
- Gq coupling: Activates PLCβ → DAG/IP3 → Ca²⁺ release
- MAPK pathway:ERK1/2 activation
- mTOR pathway: Protein synthesis regulation
- Ion channel modulation: Inhibition of K⁺ channels
- Predominantly postsynaptic
- Adjacent to NMDA receptors
- Involved in LTD and LTP
- mGluR5 is an Aβ receptor
- Aβ-mGluR5 complex triggers synaptic dysfunction
- Negative allosteric modulators: Neuroprotective
- Cognitive deficits in mGluR5 knockout
- Overactive in basal ganglia
- Contributes to dyskinesias
- mGluR5 antagonists: Anti-parkinsonian effects
- mGluR5 hypothesis: Excessive signaling
- Negative modulators: Therapeutic potential
- Clinical trials ongoing
- Critical for reward learning
- Cocaine and nicotine effects
- mGluR5 antagonists: Reduce craving
- MPEP: First generation mGluR5 NAM
- CTEP: Long-acting, brain-penetrant
- Fenobam: Clinical candidate
- CPPHA: Enhances mGluR5 signaling
- VU0360172: Highly selective
- Alzheimer's disease: Symptomatic and disease-modifying
- Fragile X: Restore synaptic function
- Parkinson's: Reduce dyskinesias
- mGluR5⁻/⁻ mice: Viable but behavioral abnormalities
- Impaired learning and memory
- Reduced anxiety
- Human GRM5 expressing mice: Enhanced phenotypes
- Disease models: Synaptic dysfunction
- Selective compounds: More brain-penetrant NAMs
- PET ligands: Imaging mGluR5 occupancy
- Biomarkers: Receptor availability as marker
- Gene therapy: Modulating expression
The study of Mglur5 Protein — Glutamate Metabotropic Receptor 5 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.