GRM6 (Glutamate Metabotropic Receptor 6)
A key G protein-coupled receptor for retinal ON-bipolar cell signaling and congenital stationary night blindness
Gene Information Card
| Symbol | GRM6 |
|---|---|
| Full Name | Glutamate Metabotropic Receptor 6 |
| Gene Type | protein-coding |
| Chromosomal Location | 5q35.3 |
| NCBI Gene ID | 2916 ncbi.nlm.nih.gov/gene/2916 |
| Ensembl ID | ENSG00000113262 |
| UniProt ID | O15303 |
| OMIM ID | 604096 |
| HGNC ID | 4598 |
| Aliases | mGluR6, GPRC1F, MGLUR6 |
Description
GRM6 encodes the metabotropic glutamate receptor 6 (mGluR6), a G protein-coupled receptor (GPCR) predominantly expressed in retinal ON-bipolar cells. It mediates synaptic transmission from photoreceptors to bipolar cells by responding to glutamate release in the dark, leading to closure of cation channels and hyperpolarization. Loss-of-function mutations in GRM6 cause autosomal recessive congenital stationary night blindness type 1B (CSNB1B).
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Congenital stationary night blindness 1B (CSNB1B) | Loss-of-function mutations impair mGluR6 signaling in ON-bipolar cells, disrupting light adaptation | ClinVar, OMIM |
| Night blindness, congenital stationary, autosomal recessive | Same mechanism as CSNB1B; biallelic GRM6 variants | OMIM #604096 |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Retina | 12.5 | High |
| Brain (cerebellum) | 0.3 | Low |
| Testis | 0.1 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| ARPE-19 (retinal pigment epithelium) | 0.0 | Not expressed |
| Y79 (retinoblastoma) | 0.0 | Not expressed |
| HEK293 | 0.0 | Not expressed |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.154C>T (p.Arg52*) | Nonsense | Rare (CSNB1B) | Loss of function; premature stop codon |
| c.2005C>T (p.Arg669Cys) | Missense | Rare (CSNB1B) | Loss of function; impaired receptor activation |
| c.2335G>A (p.Gly779Arg) | Missense | Rare (CSNB1B) | Loss of function; disrupted G protein coupling |
Mutation functional classification
Loss of Function (LOF)
Most GRM6 mutations in CSNB1B are loss-of-function, leading to absent or non-functional mGluR6.
Gain of Function (GOF)
Not reported.
Dominant Negative (DN)
Not reported.
View complete mutation data：
Gene Ontology (GO)
| • G protein-coupled receptor activity (GO:0004930) | • glutamate binding (GO:0016595) |
| • metabotropic glutamate receptor activity (GO:0008067) | • plasma membrane (GO:0005886) |
| • synaptic transmission (GO:0007268) | • phototransduction (GO:0007602) |
Pathways
• Glutamatergic synapse (KEGG hsa04724)
• Phototransduction (KEGG hsa04744)
• GPCR downstream signaling (Reactome R-HSA-388396)
Protein Summary
mGluR6 is a 877-amino acid GPCR with a large extracellular N-terminal domain (Venus flytrap domain) for glutamate binding, seven transmembrane helices, and a cytoplasmic C-terminal tail. It couples to Gi/o proteins to inhibit adenylyl cyclase and modulate ion channels. In retinal ON-bipolar cells, mGluR6 activation closes TRPM1 channels, generating the light response. The protein is highly conserved across vertebrates.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| GRM6 Knockout HEK293 Cell Line | EDJ-KQ1719 | Human | 2916 | Details Get a Quote |
| GRM6 Knockout HeLa Cell Line | EDJ-KQ53440 | Human | 2916 | Details Get a Quote |
| GRM6 Knockout A-549 Cell Line | EDJ-KQ61914 | Human | 2916 | Details Get a Quote |
| GRM6 Knockout HCT 116 Cell Line | EDJ-KQ70394 | Human | 2916 | Details Get a Quote |
Displaying Records 1 To 4 Of 4 Records
